U.S. patent application number 16/457510 was filed with the patent office on 2019-10-24 for methods for treating or preventing fibrosis at a site of a medical implant.
The applicant listed for this patent is TEMPO THERAPEUTICS, INC.. Invention is credited to Stephanie DESHAYES, Samuel TIMKO, Westbrook WEAVER.
Application Number | 20190321519 16/457510 |
Document ID | / |
Family ID | 62908788 |
Filed Date | 2019-10-24 |
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United States Patent
Application |
20190321519 |
Kind Code |
A1 |
WEAVER; Westbrook ; et
al. |
October 24, 2019 |
METHODS FOR TREATING OR PREVENTING FIBROSIS AT A SITE OF A MEDICAL
IMPLANT
Abstract
Provided are methods for the treatment and prevention of
fibrosis at a medical implant site in a subject, by administering a
microporous gel to the medical implant site. Also provided are
methods of preventing or treating an infection at the medical
implant site in a subject. Also disclosed herein are methods for
promoting healing of a wound or surgical incision at a medical
implant site in a subject, by administering a microporous gel to
the medical implant site. The microporous gel may be fluidic during
application and annealed or crosslinked after application. The
microporous gels may contain various therapeutic agents, including
antibiotics and analgesics, throughout the gel.
Inventors: |
WEAVER; Westbrook; (San
Diego, CA) ; DESHAYES; Stephanie; (San Diego, CA)
; TIMKO; Samuel; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TEMPO THERAPEUTICS, INC. |
San Diego |
CA |
US |
|
|
Family ID: |
62908788 |
Appl. No.: |
16/457510 |
Filed: |
June 28, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/US2017/068243 |
Dec 22, 2017 |
|
|
|
16457510 |
|
|
|
|
62440370 |
Dec 29, 2016 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61L 2400/12 20130101;
A61L 2430/30 20130101; A61L 27/56 20130101; A61L 27/50 20130101;
A61L 27/18 20130101; A61L 2300/802 20130101; A61L 27/52 20130101;
A61L 2400/06 20130101; B01J 13/0065 20130101; A61L 27/58 20130101;
A61L 27/14 20130101; A61L 27/54 20130101; B01J 13/0069 20130101;
A61L 27/16 20130101; B01J 19/0093 20130101 |
International
Class: |
A61L 27/52 20060101
A61L027/52; A61L 27/54 20060101 A61L027/54; A61L 27/56 20060101
A61L027/56 |
Claims
1. A method of reducing or preventing fibrosis at a site of a
medical device in a tissue of a subject, the method comprising
administering to a tissue of a subject: a. an injectable
macromolecular polymer gel comprising microgel particles, each
microgel particle having an average diameter of about 10
micrometers (.mu.m) to 500 .mu.m and comprising: 1. a backbone
polymer; and 2. an annealing component; and b. a medical
device.
2. The method of claim 1, further comprising administering to the
tissue of the subject an annealing agent, thereby linking annealing
components attached to the microgel particles to form a stabilized
macromolecular polymer gel, the stabilized macromolecular polymer
gel comprising pores having a median diameter of about 10 .mu.m to
about 100 .mu.m.
3. The method claim 1, wherein the administering the injectable
macromolecular polymer gel is performed before administering the
medical device to the tissue.
4. The method of claim 1, wherein the administering the injectable
macromolecular polymer gel is performed after administering the
medical device to the tissue.
5. The method of claim 1, wherein the administering to the tissue
the injectable macromolecular polymer gel and administering to the
tissue the medical device are performed simultaneously.
6. The methods of claim 2, wherein administering to the tissue the
annealing agent is performed before the administering to the tissue
the injectable macromolecular polymer gel.
7. The method of claim 2, wherein the administering to the tissue
the annealing agent is performed after the administering to the
tissue the injectable macromolecular polymer gel.
8. The method of claim 2, wherein the administering to the tissue
the annealing agent is performed simultaneously with the
administering to the tissue the injectable macromolecular polymer
gel.
9. The method of claim 1, wherein the medical device is a cardiac
implantable electronic device.
10. The method of claim 1, wherein the medical device is a neural
implantable electronic device.
11. The method of claim 2, further comprising stabilizing the
placement of the medical device in the tissue of the subject with
the stabilized macromolecular polymer gel.
12. The method of claim 2, wherein linking the annealing components
to form the stabilized macromolecular polymer gel is performed by
forming covalent bonds between the annealing components of the
microgel particles.
13. The method of claim 1, wherein administering the injectable
macromolecular polymer gel and administering the medical device are
performed separately.
14. The method of claim 1, further comprising purifying the
injectable macromolecular polymer gel by a process of: a.
transferring the microgel particles from a first solvent to a
second solvent by controlled addition of a third solvent to the
first solvent, wherein the second solvent is immiscible with the
first solvent; b. maintaining a single miscible phase containing
the microgel particles; and c. applying the single miscible phase
containing the microgel particles to a membrane of a membrane
filtration system; and d. removing an impurity from the microgel
particles using size exclusion filtration by the membrane
filtration system, thereby producing purified microgel
particles.
15. The method of claim 14, wherein transferring of step (a),
maintaining of step (b), and removing of step (d) are
simultaneous.
16. The method of claim 14, wherein maintaining the single miscible
phase is required for the membrane filtration system to remove the
impurity from the microgel particles.
17. The method of claim 14, wherein the membrane filtration system
is selected from the group consisting of tangential flow filtration
(TFF), ultrafiltration-diafiltration (UFDF),
microfiltration-diafiltration (MFDF), and
hollow-fiber-diafiltration (HFDF).
18. The method of claim 14, wherein the first solvent is a
non-polar oil and the second solvent is water.
19. The method of claim 14, wherein the third solvent is an alcohol
solution.
20. The method of claim 14, wherein the impurity is a surfactant.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International
Application No. PCT/US17/068243, filed on Dec. 22, 2017, which
claims the benefit of U.S. Provisional Application No. 62/440,370,
filed Dec. 29, 2016, both of which are incorporated by reference
herein in their entirety.
BACKGROUND OF THE DISCLOSURE
[0002] Current porous synthetic hydrogels used as such healing
agents are produced by methods that require toxic removal of
porogens to form pores, or degradation of encapsulated
microparticles, which requires these constructs to be either cast
ex vivo, preventing them from seamlessly integrating with the
surrounding tissue like an injectable biomaterial or requires
long-term in vivo development to resolve the porous structure.
SUMMARY OF THE DISCLOSURE
[0003] Cell migration to a site of injury or surgery is essential
for healing. Therefore, wound healing agents used at these sites
ideally do not impede cellular migration. Implantation of medical
devices, such as biomaterials, prosthetics and cardiac pacemakers,
is common practice in modern medicine. However, tissues that are
subjected to medical device implantation produce a complex set of
immune responses, including for example, to the device and the
implantation procedure, including but not limited to inflammation,
wound healing, foreign body reactions and fibrous encapsulation of
the device. These responses do not always result in a desirable
outcome for the patient. For instance, the site of implantation may
develop scar tissue or fibrotic tissue that is deleterious to the
function of the surrounding tissue and the subject.
[0004] The systems and methods disclosed herein aim to improve the
tissue-device interface through the use of microporous gel systems.
These microporous gel systems, in certain embodiments, are applied
to a surgical void, such as a medical device implantation site, and
around the medical device. A stimulus such as light is then applied
to the microporous gel system to create a microporous scaffold (see
e.g., FIG. 1). The microporous gel system disclosed herein can act
as a buffer between the tissue and the device, promoting healing of
the tissue and incorporation of the device into the tissue, while
mitigating or avoiding fibrous encapsulation of the device,
inflammation or infection. The presence of the interconnected pores
between the medical implant and the surrounding tissue (see, e.g.,
FIG. 2), provided by the microporous gel system, create a unique
environment that does not lead to a chronic inflammatory response
or fibrous tissue formation. The ability of tissue (or cells
thereof) to migrate into the material without the need for
degradation is an important aspect to the invention in the context
of implanted medical devices.
[0005] In some instances, microporous gel systems disclosed herein
provide for prevention and treatment of infections via
antimicrobial activity. In some instances, microporous gel systems
disclosed herein provide for mitigation of other negative
characteristics of surgical implant sites such as pain and chronic
inflammation. In some instances, microporous gel systems disclosed
herein provide for stable shelf products that release a tissue site
treatment (e.g., an antimicrobial treatment) when placed in a
surgical/implant site. Tissue site treatments may provide for
minimal/absent fibrosis around a surgical site pocket via
anti-fibrotic capability of microporous scaffold Tissue site
treatments may provide for minimal/absent inflammation at a
surgical site pocket via anti-inflammatory capability of
microporous scaffolds.
[0006] In some instances, microporous gel systems disclosed herein
provide for physically stabilizing medical devices in an implant or
surgical site. In some instances, microporous gel systems disclosed
herein provide for holding a medical device in place by a
microporous scaffold. In some instances, medical device of one size
can be applied to surgical/implant sites of different shapes and
sizes, with extra space in the surgical/implant site and around the
medical device filled by a microporous gel system disclosed herein
during/after implantation. Using a microporous gel system disclosed
herein, medical devices and implants of many sizes and shapes can
be interfaced with surgical pockets (in a tissue) of varying sizes
and shapes because excess surgical site space is filled by the
microporous gel system.
[0007] Features and characteristics of microporous gel systems
disclosed herein provide for applying the microporous gel systems
in a manner that is custom to a subject and the features of the
subject's surgical site or implant site. In some instances, methods
disclosed herein comprise applying a microporous gel system during
implantation of a medical device. In some instances, methods
disclosed herein comprise applying a microporous gel system during
implantation of a medical device. In some instances, methods
disclosed herein comprise applying a microporous gel system after
implantation of a medical device. In some instances, methods
disclosed herein comprise filling an implantation site or surgical
site with a microporous gel system during at least one of before,
during, and after implant positioning in the surgical site.
[0008] As one of skill in the art will understand from the
description and examples presented herein, medical device
manufacturing (size, shape, etc.) is not dependent upon
manufacturing of microporous scaffolds disclosed herein, or vice
versa. Advantageously, the adaptable, customizable microporous
scaffolds disclosed herein may be applied immediately to medical
devices of any shape, size, etc., and/or surgical pockets of any
shape, size, etc.
[0009] Disclosed herein, in some aspects, are systems comprising: a
collection of flowable microgel particles, wherein the flowable
microgel particles comprise a backbone polymer; at least one
annealing component; and a medical device, wherein the flowable
microgel particles are capable of being linked together via the at
least one annealing component to form a stabilized scaffold having
interstitial spaces therein. Also disclosed herein, in some
aspects, are systems comprising: a collection of flowable microgel
particles, wherein the flowable microgel particles comprise a
backbone polymer; at least one annealing component; and a medical
device, wherein the flowable microgel particles are linked together
via the at least one annealing component to form a stabilized
scaffold having interstitial spaces therein. The systems may
comprise an intercrosslinker that links the flowable microgel
particles together via the at least one annealing component. The
systems may comprise an annealing agent that links the flowable
microgel particles together via the at least one annealing
component. The annealing agent may be an intercrosslinking agent.
The systems may comprise a first annealing component and a second
annealing component. The first annealing component and the second
annealing component may be the same. The first annealing component
and the second annealing component may be different. The at least
one annealing component may be a substrate for an enzyme of a
mammalian subject. In some instances, a first annealing component
and a second annealing component are linked together when exposed
to a condition in a mammalian subject. The medical device may be a
medical implant. The medical device may comprise an electrode. The
medical device may comprise an electrical component. The medical
device may comprise a coating, wherein the coating comprises at
least one of the annealing component and an annealing agent. The
medical implant may be a cardiac implantable electronic device. The
cardiac implantable electronic device may be a pacemaker. The
cardiac implantable electronic device may be a defibrillator. The
medical implant may be a neural implantable electronic device. The
stabilized scaffold may maintain placement of the medical device in
a surgical void of a subject. The stabilized scaffold may have a
custom form determined by the medical device and the surgical void.
In some instances, the stabilized scaffold comprises non-covalent
bonds between the flowable microgel particles. In some instances,
the stabilized scaffold comprises covalent bonds between the
flowable microgel particles. In some instances, systems comprise a
therapeutic agent. In some instances, the therapeutic agent is an
anti-inflammatory agent, an antimicrobial agent, or an analgesic.
In some instances, the therapeutic agent is incorporated in the
stabilized scaffold. In some instances, systems comprise a
therapeutic agent, wherein the stabilized scaffold releases the
therapeutic agent from the stabilized scaffold when the stabilized
scaffold is present in a mammalian subject. In some instances, the
stabilized scaffold releases at least a portion of the therapeutic
agent from the stabilized scaffold in less than one day from its
initial presence in the mammalian subject. In some instances, the
stabilized scaffold releases the therapeutic agent from the
stabilized scaffold over a period of less than 1 day to 100 days.
In some instances, systems comprise a therapeutic agent releasing
agent that releases the therapeutic agent from the stabilized
scaffold. In some instances, the therapeutic agent is released by
tissue mediated hydrolysis. In some instances, the therapeutic
agent is released by passive hydrolysis. In some instances, the
therapeutic agent is released by a temperature change. In some
instances, systems comprise a nanoparticle. In some instances, the
therapeutic agent is connected to or contained within the
nanoparticle. In some instances, the nanoparticle is a mesoporous
silica nanoparticle. In some instances, the nanoparticle comprises
poly(lactic-co-glycolic acid). In some instances, the nanoparticle
comprises chitosan. In some instances, the nanoparticle comprises
hyaluronic acid. In some instances, the nanoparticle comprises a
poly(anhydride), a poly(amide), a poly(ortho ester), a
polycaprolactone, or a combination thereof. In some instances, the
nanoparticle comprises a polymer with a lower critical solution
temperature (LCST). In some instances, the polymer is
poly(N-isopropylacrylamide) or a co-polymer thereof. In some
instances, the nanoparticle comprises a polymer with an upper
critical solution temperature (UCST). In some instances, the
polymer is poly(hydroxyethylmethacrylate), polyethylene oxide, or
poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide). In
some instances, the nanoparticle comprises a self-immolating
polymer. In some instances, the polymer is poly(p-aminobenzyl
oxycarbonyl). In some instances, the polymer is capped with a cage
that can be released upon a stimulus. In some instances, the system
comprises a core-shell nanoparticle system. In some instances, a
first portion of the flowable microgel particles comprises the
core-shell nanoparticle system and wherein the second portion of
flowable microgel particles comprises a shell-dissolving agent,
wherein the shell-dissolving agent is capable of releasing the
therapeutic agent when the first portion of the flowable microgel
particles is in contact with the second portion of flowable
microgel particles. In some instances, systems comprise a first
container containing the first portion and a second container
containing the second portion. In some instances, the
intercrosslinker is degradable in a mammalian subject. In some
instances, systems comprise a cell adhesive peptide. In some
instances, the annealing agent comprises a light source. In some
instances, the collection of flowable microgel particles and
annealing agent are stored or administered from a single container.
In some instances, at least two of the flowable microgel particles
are present in separate containers. In some instances, the first
annealing component and the second annealing component are present
in separate containers. In some instances, systems comprise an
application device, wherein the application device is configured to
apply the flowable microgel particles and the at least one
annealing component to a tissue of a subject. In some instances,
the application device comprises a syringe, a spatula, a squeezable
tube or a cannula. In some instances, the application device
comprises a multi-barrel syringe, and wherein at least a first
portion of the flowable microgel particles or a first portion of
the annealing component is in a first barrel, and a second portion
of the flowable microgel particles or a second portion of the
annealing component is in a second barrel. In some instances, the
microporous gel system has a shelf life of at least about one year
at room temperature.
[0010] Disclosed herein, in some aspects, are systems comprising: a
collection of flowable microgel particles, wherein the flowable
microgel particles comprise a backbone polymer; at least one
annealing component; and a medical device, wherein the flowable
microgel particles are capable of being linked together via the at
least one annealing component to form a stabilized scaffold having
interstitial spaces therein, for use in the treatment of a wound or
surgical site.
[0011] Disclosed herein, in some aspects are methods of treating a
site of a medical device in a tissue of a subject comprising
administering to the site: a collection of flowable microgel
particles, wherein the flowable microgel particles comprise a
backbone polymer; at least one annealing component; and a medical
device, wherein the flowable microgel particles are capable of
being linked together via the at least one annealing component to
form a stabilized scaffold having interstitial spaces therein.
[0012] Disclosed herein, in some aspects, are methods of reducing
or preventing fibrosis at a site of a medical device in a tissue of
a subject comprising administering to the site: a collection of
flowable microgel particles, wherein the flowable microgel
particles comprise a backbone polymer; at least one annealing
component; and a medical device, wherein the flowable microgel
particles are capable of being linked together via the at least one
annealing component to form a stabilized scaffold having
interstitial spaces therein.
[0013] Disclosed herein, in some aspects, are methods of reducing
or preventing inflammation at a site of a medical device in a
tissue of a subject comprising administering to the site: a
collection of flowable microgel particles, wherein the flowable
microgel particles comprise a backbone polymer; at least one
annealing component; and a medical device, wherein the flowable
microgel particles are capable of being linked together via the at
least one annealing component to form a stabilized scaffold having
interstitial spaces therein. In some instances, the medical device
is a surgical device. In some instances, the medical device is a
medical implant. In some instances, methods comprise administering
at least one of the annealing component and the flowable microgel
particles to the site before administering the medical device to
the site. In some instances, methods comprise administering at
least one of the annealing component and the flowable microgel
particles to the site after administering the medical device to the
site. In some instances, methods comprise co-administering at least
one of the annealing component and the flowable microgel particles,
and the medical device to the site. In some instances, methods
comprise administering at least one of the annealing component and
the flowable microgel particles with a syringe, cannula, squeezable
tube or spatula. In some instances, methods comprise administering
an annealing agent. In some instances, methods comprise
administering the annealing agent before administering at least one
of the annealing component and the flowable microgel particles. In
some instances, methods comprise administering the annealing agent
after administering at least one of the annealing component and the
flowable microgel particles. In some instances, methods comprise
co-administering the annealing agent and at least one of the
annealing component and the flowable microgel particles. In some
instances, methods comprise administering a therapeutic agent to
the site. In some instances, methods comprise administering a
therapeutic agent releasing agent to the site, wherein the
therapeutic agent releasing agent releases the therapeutic agent
from the stabilized scaffold to the site or tissue. In some
instances, methods comprise incorporating the therapeutic agent
into the stabilized scaffold. In some instances, the stabilized
scaffold comprises a core-shell nanoparticle system wherein the
therapeutic agent is connected to or contained within the
core-shell nanoparticle system, comprising applying an external
stimulus to the stabilized scaffold to release the therapeutic
agent to the site or tissue. In some instances, the external
stimulus selected from light, electromagnetic radiation, or
temperature change. In some instances, methods comprise changing a
condition of the site after formation of the stabilized scaffold.
In some instances, methods comprise changing a condition of the
site before formation of the stabilized scaffold. In some
instances, changing the condition comprises at least one of
changing temperature of the site, changing pH of the site, changing
chemistry of the site, applying an exogenous enzyme, activating an
endogenous enzyme, applying a magnetic field, applying a form of
radiation, applying light, and applying ultrasound.
[0014] Disclosed herein, in some aspects, are methods of treating a
heart condition comprising administering to a subject in need
thereof: a collection of flowable microgel particles, wherein the
flowable microgel particles comprise a backbone polymer; at least
one annealing component; and a cardiac implantable electronic
device, wherein the flowable microgel particles are capable of
being linked together via the at least one annealing component to
form a stabilized scaffold having interstitial spaces therein. In
some instances, the heart condition is a heart arrhythmia. In some
instances, the heart condition is a sustained ventricular
tachycardia. In some instances, the heart condition is a
ventricular fibrillation.
[0015] Disclosed herein, in some aspects are methods of treating a
neurological condition comprising administering to a subject in
need thereof: a collection of flowable microgel particles, wherein
the flowable microgel particles comprise a backbone polymer; at
least one annealing component; and a neural implantable electronic
device, wherein the flowable microgel particles are capable of
being linked together via the at least one annealing component to
form a stabilized scaffold having interstitial spaces therein.
[0016] Disclosed herein, in some aspects, are methods of producing
a microporous scaffold, comprising: synthesizing a first portion of
flowable microgel particle in the presence of a first annealing
component and a second annealing component, wherein there is more
of the first annealing component than the second annealing
component to produce a first functionalized microgel particle;
synthesizing a second portion of flowable microgel particle in the
presence of the first annealing component and the second annealing
component, wherein there is more of the second annealing component
than the first annealing component to produce a second
functionalized microgel particle; combining the first
functionalized microgel particle and the second functionalized
microgel particle such that the first functionalized microgel
particle and the second functionalized microgel particle connect,
thereby producing a microporous scaffold of microgel particles
having interstitial spaces therebetween. In some instances, there
is at least 1% more of the first annealing component than the
second annealing component in step (a). In some instances, there is
at least 1% more of the second annealing component than the first
annealing component in step (b). In some instances, at least one of
the first annealing component and the second annealing component
comprise a functional group selected from a vinyl sulfone, thiol,
amine, imidazole, aldehyde, ketone, hydroxyl, azide, alkyne, vinyl,
alkene, maleimide, carboxyl, N-hydroxysuccinimide (NHS) ester,
isocyanate, isothiocyanate, hydroxylamine, and thione. In some
instances, the first functionalized microgel particle and the
second functionalized microgel particle connect through a reaction
selected from Michael addition, amide bond coupling, Diels-Alder
cycloaddition, Huisgen 1,3-dipolar cycloaddition, reductive
amination, carbamate linkage, ester linkage, thioether linkage,
disulfide bonding, hydrazone bonding, oxime coupling, and thiourea
coupling. In some instances, the first functionalized microgel
particle and the second functionalized microgel particle connect to
produce a covalent bond. In some instances, the first
functionalized microgel particle and the second functionalized
microgel particle connect to produce a non-covalent bond. In some
instances, the first functionalized microgel particle and the
second functionalized microgel particle connect to produce a
connection selected from a C--C bond, an amide bond, an amine bond,
a carbamate linkage, an ester linkage, a thioether linkage, a
disulfide bond, a hydrazine bond, an oxime coupling and a thiourea
coupling. In some instances, at least one step of the method is
performed in situ.
[0017] Disclosed herein, in some aspects, are methods of producing
a microporous scaffold, comprising: synthesizing flowable microgel
particles; contacting a first portion of the flowable microgel
particles with a first annealing component to produce a first
functionalized microgel particle; contacting a second portion of
the flowable microgel particles with a second annealing component
to produce a second functionalized microgel particle; combining the
first functionalized microgel particle and the second
functionalized microgel particle such that the first functionalized
microgel particle and the second functionalized microgel particle
connect, thereby producing a microporous scaffold of microgel
particles having interstitial spaces therebetween. In some
instances, at least one of the first annealing component and the
second annealing component comprise a reactive moiety selected from
a catechol, a sialic acid, a boronic acid, a molecular cage,
adamantane, biotin, and streptavidin. In some instances, the
molecular cage is selected from a cyclodextrin, a cucurbituril, a
calixarene, a pillararene, a crown ether, a cavitand, a cryptand,
and a carcerand. In some instances, the first functionalized
microgel particle and the second functionalized microgel particle
connect through a covalent bond. In some instances, the covalent
bond is selected from an amide, ester, C--C bond, carbamate,
disulfide bond, oxime, thiourea, hydrazone, and imine. In some
instances, the first functionalized microgel particle and the
second functionalized microgel particle connect through a
non-covalent bond. In some instances, the non-covalent bond is
selected from an electrostatic interaction, a hydrogen bond, a
cation-.pi., .pi.-.pi. stack, a metal-ligand bond, a van der Waals
interaction, and a non-covalent host-guest inclusion complex. In
some instances, at least one step of the method is performed in
situ. In some instances, methods comprise contacting the first
functionalized microgel particle and the second functionalized
microgel particle with an intercrosslinker in order to connect the
first functionalized microgel particle and the second
functionalized microgel particle. In some instances, contacting
occurs in situ. In some instances, contacting occurs after
synthesizing the flowable microgel particles. In some instances,
the intercrosslinker comprises at least one functional group. In
some instances, the intercrosslinker comprises at least two
functional groups. In some instances, at least one functional group
is selected from a vinyl sulfone, a thiol, an amine, an imidazole,
an aldehyde, a ketone, a hydroxyl, an azide, an alkyne, a vinyl, an
alkene, a maleimide, a carboxyl, a N-Hydroxysuccinimide (NHS)
ester, an isocyanate, an isothiocyanate, ahydroxylamine, and a
thione. In some instances, connecting the first functionalized
microgel particle and the second functionalized microgel particle
comprises a reaction selected from Michael addition, amide bond
coupling, Diels-Alder cycloaddition, Huisgen 1,3-dipolar
cycloaddition, reductive amination, carbamate linkage, ester
linkage, thioether linkage, disulfide bond, hydrazone bond, oxime
coupling, and thiourea coupling. In some instances, methods
comprise contacting the first functionalized microgel particle and
the second functionalized microgel particle with an
intercrosslinking agent. In some instances, the intercrosslinking
agent comprises a reducing agent. In some instances, the reducing
agent comprises at least one of dithiothreitol, dithioerythritol,
L-glutathione, and tris (2-carboxyethyl) phosphine hydrochloride.
In some instances, the intercrosslinking agent comprises an
oxidizing agent. In some instances, the oxidizing agent comprises
at least one of horseradish peroxidase (HRP), sodium periodate, and
silver nitrate. In some instances, the intercrosslinking agent
induces self-crosslinking of functional groups present on at least
one of the annealing component flowable microgel particles or
annealing components to produce a crosslinkage. In some instances,
the crosslinkage comprises at least one of a covalent bond, a
coordination complex, a hydrogen bond, an electrostatic
interaction, a cation-.pi. interaction, a .pi.-.pi. stack, and a
van der Waals interaction. In some instances, methods comprise
contacting the first functionalized microgel particle and the
second functionalized microgel particle with the intercrosslinking
agent in situ. In some instances, methods comprise applying an
external stimulus to the microporous scaffold to release the
intercrosslinker. In some instances, applying an external stimulus
to the microporous scaffold occurs indirectly by applying the
external stimulus to tissue around the microporous scaffold. In
some instances, the external stimulus is selected from light, an
electromagnetic field, ultrasound, heat, cooling, and a combination
thereof. In some instances, methods comprise incorporating a
therapeutic agent into the stabilized scaffold. In some instances,
incorporating comprises at least one of diffusing the therapeutic
agent into the collection of flowable microgel particles;
covalently linking the therapeutic agent to the flowable microgel
particles; and photo-caging the therapeutic agent to the microgel
particles. In some instances, incorporating comprises encapsulating
the therapeutic agent in a nanoparticle, and mixing the therapeutic
agent and the nanoparticle with the flowable microgel particles. In
some instances, the nanoparticle and the therapeutic agent are
lyophilized, comprising dissolving the nanoparticle and the
therapeutic agent in aqueous buffer prior to mixing the
nanoparticle and the therapeutic agent with the flowable microgel
particles. In some instances, transferring and removing occur
substantially simultaneously.
[0018] Disclosed herein, in some aspects, are methods of purifying
flowable microgel particles comprising: obtaining a membrane
filtration system; transferring flowable microgel particles from a
first solvent to a second solvent, wherein the second solvent is
immiscible with the first solvent, by controlled addition of a
third solvent to the first solvent such that a single miscible
phase containing the flowable microgel particles is maintained; and
removing an impurity from the flowable microgel particles. In some
instances, transferring and removing occur substantially
simultaneously. In some instances, the membrane filtration system
requires a single miscible phase for function. In some instances,
the membrane filtration system is selected from tangential flow
filtration (TFF), ultrafiltration-diafiltration (UFDF),
microfiltration-diafiltration (MFDF), or hollow-fiber-diafiltration
(HFDF). In some instances, the first solvent is a non-polar oil and
the second solvent is water. In some instances, the third solvent
is an alcohol solution. In some instances, the impurity is a
surfactant.
[0019] Disclosed herein, in some aspects, are methods of
concentrating flowable microgel particles in a solution or
suspension comprising: pumping the flowable microgel particles
through a membrane filtration system while a continuous phase
volume is removed; continually concentrating the flowable microgel
particles at a controlled membrane flux; and maintaining a wall
shear stress inside the membrane filtration system. In some
instances, the membrane filtration system is selected from
tangential flow filtration (TFF), ultrafiltration-diafiltration
(UFDF), microfiltration-diafiltration (MFDF), or
hollow-fiber-diafiltration (HFDF). In some instances, the membrane
flux is controlled between 100 and 1000 L/m.sup.2h. In some
instances, the wall shear stress is maintained between 100 s.sup.-1
and 10,000 s.sup.-1.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Various aspects of the disclosure are set forth with
particularity in the appended claims. A better understanding of the
features and advantages of the present disclosure will be obtained
by reference to the following detailed description that sets forth
illustrative embodiments, in which the principles of the disclosure
are utilized, and the accompanying drawings of which:
[0021] FIG. 1 shows an exemplary application of a microporous gel
disclosed herein to a wound void with a medical device implant. A
syringe applicator of a solution of free flowing microgel particles
is applied to the wound void. Microgel particles are annealed using
light energy to form a porous network. The porous network allows
cells to migrate through the gel, with the result of improving the
health of the wound-device interface.
[0022] FIG. 2 shows an exemplary wound, wherein a microporous
scaffold has been formed between the medical implant and the
surrounding tissue. The presence of interconnected pores, with or
without cells that have migrated into the microporous scaffold, are
represented by the black color between the silver spherical shapes,
the latter of which represent the microgel particles.
[0023] FIG. 3 shows an exemplary method of controlling the release
of diffusible molecules (active pharmaceutical ingredients) into
the microporous gel. By combining multiple diffusion rates,
dependent upon diffusion rates only (gel) and multiple mechanisms
including enzymatic, hydrolytic, photonic, and thermal
(nanoparticles), the microporous gel can achieve highly complex
release profiles DIRECTLY to the cells growing through it (unlike
any other scaffolding systems).
[0024] FIG. 4 shows an exemplary schematic representation of
pre-functionalization of flowable microgel particles.
[0025] FIG. 5 shows an exemplary schematic representation of
post-functionalization of flowable microgel particles.
[0026] FIG. 6 shows an exemplary schematic representation of in
situ addition of a crosslinking agent.
[0027] FIG. 7 shows an exemplary schematic representation of in
situ addition of a crosslinking agent.
[0028] FIG. 8 shows an exemplary schematic diagram of flowable
microgel particle synthesis by a water-in-oil emulsion and
purification by tangential flow filtration.
[0029] FIG. 9 shows an exemplary workflow of purifying flowable
microgel particles, aiming to maintain one miscible continuous
phase with isopropanol, which is miscible with both oil and water,
as an intermediate solvent to transfer the particles, initially
dispersed in oil, into water, and finally to an aqueous buffer.
[0030] FIG. 10A-10C show characterization of wounds in pigs treated
with a flowable microgel particle system disclosed herein five days
after treatment. FIG. 10A shows multinucleated giant cell (MNGC)
formation. FIG. 10B shows acute inflammation. FIG. 10C shows wound
atrophy was reduced the microporous scaffold.
[0031] FIG. 11A-11B show characterization of wounds in pigs treated
with a flowable microgel particle system disclosed herein fourteen
days after treatment. FIG. 11A shows re-epithelialization. FIG. 11B
shows quantification of fibrosis.
[0032] FIG. 12A-12C show augmentation of wound healing
vascularization with a flowable microgel particle system disclosed
herein five days after treatment. FIG. 12A shows quantification of
vessel ingrowth. FIG. 12B shows sizes of vessels formed. FIG. 12C
shows the percentage of vessels larger than 10 .mu.m.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0033] Medical devices, such as implants and surgical instruments,
are used for a wide variety of applications. Use of these tools can
be complicated by inflammation, infection, pain, scarring, and
inability of an implant site or surgical site to heal or repair.
The microporous gel systems disclosed herein may initially exist in
a fluidic state, as a composition of flowable microgel particles in
a solution. For example, in certain application, this solution is
applied to the implant or surgical site in a subject before, after
and/or concurrently with application of the medical device to
improve the health and healing of the site. Due to its fluidic
nature, the microporous gel system completely fills any space that
may remain in the site surrounding the medical device. Once the
solution and medical device are applied, an annealing agent is
added or activated to anneal the microgel particles, creating a
microporous scaffold. The microporous gel systems disclosed herein,
unlike other porous gel systems, do not require porogens to produce
the micropores of the scaffold. Instead, the microporous gel
systems disclosed herein comprise microgel particles that are
annealed and/or crosslinked together while allowing for micropores
to form between the microgel particles. Cells of the subject can,
in certain applications, migrate through the micropores of the
scaffold aiding in healing the site. By way of non-limiting
example, healing the site may comprise vascularizing, depositing
extracellular matrix, and producing proteins and enzymes that aid
in healing. In addition to aiding healing, the annealed scaffold
may act as a functional glue to maintain the medical device
placement in the site. The nature of the fluid-to-scaffold property
in vivo provides a custom fit for the device; for example, a
one-size-fits-all for the medical device. The microporous gel
systems may also comprise therapeutic agents to treat the site for
inflammation, pain or infection. The therapeutic agents include,
but are not limited to, anti-inflammatory agents, analgesics, and
antimicrobials. Therapeutic agents specific to the site may also be
used. For example, the medical implant may be a cardiac pacemaker,
and a therapeutic agent specific to the implantation site may be an
antimicrobial agent.
Certain Terminologies
[0034] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as is commonly understood by one
of skill in the art to which the claimed subject matter belongs. It
is to be understood that the foregoing general description and the
following examples are exemplary and explanatory only and are not
restrictive of any subject matter claimed. In this application, the
use of the singular includes the plural unless specifically stated
otherwise. It must be noted that, as used in the specification and
the appended claims, the singular forms "a," "an" and "the" include
plural referents unless the context clearly dictates otherwise. In
this application, the use of "or" means "and/or" unless stated
otherwise. Furthermore, use of the term "including" as well as
other forms, such as "include", "includes," and "included," is not
limiting.
[0035] As used herein, ranges and amounts can be expressed as
"about" a particular value or range. About also includes the exact
amount. For example, "about 5 .mu.L" means "about 5 .mu.L" and also
"5 .mu.L." Generally, the term "about" includes an amount that
would be expected to be within experimental error. The term "about"
includes values that are within 10% less to 10% greater of the
value provided. For example, "about 50%" means "between 45% and
55%." Also, by way of example, "about 30" means "between 27 and
33."
[0036] The section headings used herein are for organizational
purposes only and are not to be construed as limiting the subject
matter described.
[0037] As used herein, the terms "individual(s)", "subject(s)" and
"patient(s)" mean any mammal. In some embodiments, the mammal is a
human. In some embodiments, the mammal is a non-human.
[0038] The term "statistically significant" or "significantly"
refers to statistical significance and generally means a two
standard deviation (2 SD) below normal, or lower, concentration of
the marker. The term refers to statistical evidence that there is a
difference. It is defined as the probability of making a decision
to reject the null hypothesis when the null hypothesis is actually
true. The decision is often made using the p-value. A p-value of
less than 0.05 is considered statistically significant.
[0039] As used herein, the term "treating" and "treatment" refers
to administering to a subject an effective amount of a composition
so that the subject as a reduction in at least one symptom of the
disease or an improvement in the disease, for example, beneficial
or desired clinical results. For purposes of this invention,
beneficial or desired clinical results include, but are not limited
to, alleviation of one or more symptoms, diminishment of extent of
disease, stabilized (e.g., not worsening) state of disease, delay
or slowing of disease progression, amelioration or palliation of
the disease state, and remission (whether partial or total),
whether detectable or undetectable. Alternatively, treatment is
"effective" if the progression of a disease is reduced or halted.
Those in need of treatment include those already diagnosed with a
disease or condition, as well as those likely to develop a disease
or condition due to genetic susceptibility or other factors which
contribute to the disease or condition, such as a non-limiting
example, weight, diet and health of a subject are factors which may
contribute to a subject likely to develop diabetes mellitus. Those
in need of treatment also include subjects in need of medical or
surgical attention, care, or management.
[0040] Without further elaboration, it is believed that one skilled
in the art, using the preceding description, can utilize the
present invention to the fullest extent. The following examples are
illustrative only, and not limiting of the remainder of the
disclosure in any way whatsoever.
Systems
[0041] Provided herein are systems comprising a microporous gel
system disclosed herein and a medical device disclosed herein.
Microporous gel systems disclosed herein generally comprise a
collection of flowable microgel particles and at least one
annealing component. Microporous gel systems disclosed herein may
comprise an annealing agent that links the flowable microgel
particles together via the annealing component to form a stabilized
scaffold. The microporous gel system may also simply be referred to
herein as a "gel" or "hydrogel." Alternatively, or additionally,
microporous gel systems disclosed herein may comprise a crosslinker
that links the flowable microgel particles together via the
annealing component. In general, resulting stabilized scaffolds
comprise interstitial spaces therein. By way of non-limiting
example, medical devices include cardiac implantable electronic
devices and neural implantable electronic devices.
[0042] Systems disclosed herein may comprise a container to contain
the microporous gel system, e.g., a bottle, tube, syringe, syringe
barrel, or plastic bag. Systems disclosed herein may comprise an
application device for applying the microporous gel system to a
tissue defect. The container may be the application device, may be
used with the application device, or may be used instead of the
application device.
[0043] The collection of flowable microgel particles and an
annealing agent may be stored in a single container. The collection
of flowable microgel particles and annealing agent may be
administered from a single container. Additional components of the
systems, such as crosslinkers, therapeutic agents, therapeutic
agent releasing agents, nanoparticles, and cell adhesive peptides,
including all those disclosed herein, may be stored or administered
from the single container or a separate container.
[0044] The collection of flowable microgel particles may be stored
in a first container and the annealing agent may be stored in a
second container. The collection of flowable microgel particles may
be administered from a first container and the annealing agent may
be administered from a second container.
[0045] In some instances, a first portion of the flowable microgel
particles is administered from a first container and a second
portion of the flowable microgel particles is administered from a
second container. Contents of first and second containers may be
administered sequentially. Contents of first and second containers
may be administered simultaneously.
[0046] Any one of the systems disclosed herein may comprise an
application device to apply the microporous gel system to a tissue
of a subject. By way of non-limiting example, the application
device may comprise a syringe, a spatula, a squeezable tube, a
cannula, or any combination thereof. The application device may
comprise a needle. The needle may be blunt so as to avoid damaging
or piercing a tissue. The microporous gel may have a viscosity low
enough before annealing to be sprayed on the tissue of the subject.
Thus, the application device may comprise a spray mechanism.
[0047] Containers and application devices disclosed herein
encompass a wide range of volumes that are suitable for application
to a wound, surgical or implant site receiving a medical device.
Volumes include, but are not limited to, about 0.1 mL to about 0.5
L, about 0.1 mL to about 0.2 L, about 0.1 mL to about 0.1 L, about
0.1 mL to about 75 mL, about 0.1 mL to about 60 mL, about 0.1 mL to
about 50 mL, about 0.1 mL to about 25 mL, about 0.1 mL to about 20
mL, about 0.1 mL to about 10 mL, about 1 mL to about 0.5 L, about 1
mL to about 0.2 L, about 1 mL to about 1 L, about 1 mL to about 75
mL, about 1 mL to about 60 mL, about 1 mL to about 50 mL, about 1
mL to about 25 mL, about 1 mL to about 20 mL, or about 1 mL to
about 10 mL.
Microporous Gel Systems
[0048] Provided herein are methods and systems for treating a
condition in a subject in need thereof, comprising administering to
the subject a microporous gel system disclosed herein. Microporous
gel systems may also simply be referred to herein as a "gel" or
"hydrogel." The microporous gel systems disclosed herein may take
different forms, and, unless otherwise specified, the various terms
that are used to reference these forms, such as microporous gel
scaffold, stabilized scaffold, collection of flowable microgel
particles, and microporous gel, may be used interchangeably herein.
The microporous gel system may be administered to a site in the
subject before, after or simultaneously with application of an
implant or surgical device disclosed herein to the site. The
microporous gel systems disclosed herein may comprise a collection
of flowable microgel particles comprising a backbone polymer and an
annealing component. Flowable microgel particles may also be
referred to herein simply as "microgel particles." Methods of
synthesizing flowable microgel particles are disclosed herein.
Flowable Microgel Particles
[0049] The flowable microgel particles may be spherical particles
or roughly spherical particles. The flowable microgel particles may
be irregular shaped or polygonal shaped. The flowable microgel
particles may have a diameter or dimension (e.g., length, width,
height, axis). The flowable microgel particles may have an average
diameter or dimension of about 10 micrometers. The flowable
microgel particles may have an average diameter or dimension of
about 15 micrometers. The flowable microgel particles may have an
average diameter or dimension of about 25 micrometers. The flowable
microgel particles may have a diameter or dimension of about 50
micrometers. The flowable microgel particles may have an average
diameter or dimension of about 100 micrometers. The flowable
microgel particles may have an average diameter or dimension of
about 150 micrometers. The flowable microgel particles may have an
average diameter or dimension of about 200 micrometers. The
flowable microgel particles may have a diameter or dimension within
the range of about 10 micrometers to about 500 micrometers. The
flowable microgel particles may have a diameter or dimension within
the range of about 10 micrometers to about 200 micrometers. The
flowable microgel particles may have a diameter or dimension within
the range of about 15 micrometers to about 200 micrometers. The
flowable microgel particles may have a diameter or dimension within
the range of about 15 micrometers to about 150 micrometers. The
flowable microgel particles may have a diameter or dimension within
the range of about 30 micrometers to about 100 micrometers.
[0050] The flowable microgel particles may have an average diameter
or dimension of 10 micrometers. The flowable microgel particles may
have an average diameter or dimension of 15 micrometers. The
flowable microgel particles may have an average diameter or
dimension of 25 micrometers. The flowable microgel particles may
have a diameter or dimension of 50 micrometers. The flowable
microgel particles may have an average diameter or dimension of 100
micrometers. The flowable microgel particles may have an average
diameter or dimension of 150 micrometers. The flowable microgel
particles may have an average diameter or dimension of 200
micrometers. The flowable microgel particles may have a diameter or
dimension within the range of 10 micrometers to 500 micrometers.
The flowable microgel particles may have a diameter or dimension
within the range of 10 micrometers to 200 micrometers. The flowable
microgel particles may have a diameter or dimension within the
range of 15 micrometers to 200 micrometers. The flowable microgel
particles may have a diameter or dimension within the range of 15
micrometers to 150 micrometers. The flowable microgel particles may
have a diameter or dimension within the range of 30 micrometers to
100 micrometers. The diameter or dimension of the flowable microgel
particles may depend on a component or property of a solvent in
which they are dispersed before the microporous gel system becomes
a stabilized scaffold. The solvent may be water. The solvent may be
isotonic with blood of the subject. The solvent may be a saline
solution. The solvent may be a buffered saline solution. In certain
embodiments, the solvent is acidic. The solvent may have a pH of
about 4 to about 7. The solvent may have a pH of about 3, about 4,
about 5, about 6, or about 7. In certain embodiments, the solvent
is alkaline. The solvent may have a pH greater than 7. The solvent
may have a pH of about 8, about 9 or about 10.
Backbone Polymers
[0051] Flowable microgel particles disclosed herein comprise at
least one backbone polymer. By way of non-limiting example, the
backbone polymer may comprise a polymer selected from poly(ethylene
glycol), hyaluronic acid, polyacrylamide, or polymethacrylate. The
backbone polymer of the flowable microgel particles disclosed
herein may comprise a hydrophilic polymer, amphiphilic polymer,
synthetic or natural polymer (e.g., poly(ethylene glycol) (PEG),
poly(propylene glycol), poly(hydroxyethylmethacrylate), hyaluronic
acid (HA), gelatin, fibrin, chitosan, heparin, heparan, and
synthetic versions of HA, gelatin, fibrin, chitosan, heparin, or
heparan). The backbone polymer of the flowable microgel particles
disclosed herein may be made from any natural (e.g., modified HA)
or synthetic polymer (e.g., PEG) capable of forming a hydrogel. The
backbone polymer may comprise a natural polymer containing
nitrogen, such as proteins and derivatives, including crosslinked
or modified gelatins, and keratins. The backbone polymer may
comprise a vinyl polymer such as poly(ethyleneglycol) acrylate,
poly(ethyleneglycol) methacrylate, poly(ethyleneglycol) vinyl
sulfone, poly(ethyleneglycol) maleimide, poly(ethyleneglycol)
norbornene, poly(ethyleneglycol) allyl. The backbone polymer may
comprise a polyacrylamide or a polymethacrylates. The backbone
polymer may comprise a polyester, a polyamide, a polyurethane, and
a mixture or copolymer thereof. The backbone polymer may comprise a
graft copolymer obtained by initializing polymerization of a
synthetic polymer on a preexisting natural polymer.
[0052] The flowable microgel particles disclosed herein may,
alternatively or additionally to the backbone polymer, comprise a
suitable support material. The support material may be suitable for
most tissue engineering/regenerative medicine applications. The
support material is generally biocompatible and preferably
biodegradable. Examples of suitable support material include, but
are not limited to, natural polymeric carbohydrates and their
synthetically modified, crosslinked, or substituted derivatives,
such as gelatin, agar, agarose, crosslinked alginic acid, chitin,
substituted and crosslinked guar gums, cellulose esters, especially
with nitrous acids and carboxylic acids, mixed cellulose esters,
and cellulose ethers; natural polymers containing nitrogen, such as
proteins and derivatives, including crosslinked or modified
gelatins, and keratins; vinyl polymers such as
poly(ethyleneglycol)acrylate/methacrylate/vinyl
sulfone/maleimide/norbornene/allyl, polyacrylamides,
polymethacrylates, copolymers and terpolymers of the above
polycondensates, such as polyesters, polyamides, and other
polymers, such as polyurethanes; and mixtures or copolymers of the
above classes, such as graft copolymers obtained by initializing
polymerization of synthetic polymers on a preexisting natural
polymer. A variety of biocompatible and biodegradable polymers are
available for use in therapeutic applications; examples include:
polycaprolactone, polyglycolide, polylactide,
poly(lactic-co-glycolic acid) (PLGA), and
poly-3-hydroxybutyrate.
[0053] The backbone polymer may be present at a concentration of
about 1% w/v to about 15% w/v of the microporous gel. The backbone
polymer may be present at a concentration of 1% w/v to 15% w/v of
the microporous gel. The backbone polymer may be present at a
concentration of about 2% w/v to about 10% w/v of the microporous
gel. The backbone polymer may be present at a concentration of 2%
w/v to 10% w/v of the microporous gel. The backbone polymer may be
present at a concentration of about 1% w/v of the microporous gel.
The backbone polymer may be present at a concentration of about 2%
w/v of the microporous gel. The backbone polymer may be present at
a concentration of about 3% w/v of the microporous gel. The
backbone polymer may be present at a concentration of about 4% w/v
of the microporous gel. The backbone polymer may be present at a
concentration of about 5% w/v of the microporous gel. The backbone
polymer may be present at a concentration of about 6% w/v of the
microporous gel. The backbone polymer may be present at a
concentration of about 7% w/v of the microporous gel. The backbone
polymer may be present at a concentration of about 8% w/v of the
microporous gel. The backbone polymer may be present at a
concentration of about 9% w/v of the microporous gel. The backbone
polymer may be present at a concentration of about 10% w/v of the
microporous gel. The backbone polymer may be present at a
concentration of about 11% w/v of the microporous gel. The backbone
polymer may be present at a concentration of 12% w/v of the
microporous gel.
Annealing Components
[0054] Microporous gel systems disclosed herein generally comprise
at least one annealing component. In many cases, annealing
components are merely functional groups comprising a reactive
moiety. By way of non-limiting example, the reactive moiety may
comprise at least one functional group selected from a vinyl
sulfone, thiol, amine, imidazole, aldehyde, ketone, hydroxyl,
azide, alkyne, vinyl, alkene, maleimide, carboxyl,
N-hydroxysuccinimide (NHS) ester, isocyanate, isothiocyanate,
hydroxylamine, and thione. The annealing component may comprise a
vinyl group. The annealing component may comprise a free cysteine.
The annealing component may comprise a thiol. The annealing
component may comprise an amine. The annealing component may
comprise a reactive moiety. The reactive moiety may comprise a
catechol (e.g., L-DOPA, dopamine). The reactive moiety may comprise
sialic acid (e.g. neuraminic acid). The reactive moiety may
comprise boronic acid (e.g., 3-aminophenylboronic acid). The
reactive moiety may comprise a molecular cage (e.g., cyclodextrin,
cucurbituril, calixarene, pillararene, crown ether, cavitand,
cryptands carcerand). The reactive moiety may comprise adamantane.
The reactive moiety may comprise biotin. The reactive moiety may
comprise streptavidin.
[0055] Annealing components disclosed herein may include large
biological molecules. The annealing component may comprise a
peptide. The annealing component may consist essentially of a
peptide. In some instances, the annealing component comprises a
nucleic acid. The annealing component may consist essentially of a
nucleic acid. The annealing component may comprise a protein. The
annealing component may comprise an antibody or antigen binding
antibody fragment. The annealing component may comprise an epitope.
The annealing component may comprise an enzymatic substrate. The
annealing component may be provided by the subject. By way of
non-limiting example, the annealing component may comprise a
transglutaminase substrate (e.g., fibrin). A non-limiting example
of a transglutaminase is enzyme Factor XIII. In this case,
endogenous Factor XIII acts as an annealing agent on fibrin to form
.gamma.-glutamyl- -lysyl amide cross links between fibrin
molecules. Another non-limiting example of an annealing component
is a collagen peptide. The collagen peptide may be a K peptide
(K-peptide: Ac-FKGGERCG-NH2). The collagen peptide may be a Q
peptide (Q peptide: Ac-NQEQVSPLGGERCG-NH2). In some instances, K
peptide and Q peptide serve as annealing components as well as cell
adhesive peptides.
Crosslinkers
[0056] Microporous gel systems disclosed herein may comprise at
least one crosslinker. In some instances, at least a portion of the
flowable microgel particles comprise a crosslinker. In some
instances, at least a portion of the flowable microgel particles
are interlinked by a crosslinker. The crosslinker may be an
intracrosslinker, providing intracrosslinking (intracrosslinks)
within the flowable microgel particles. The crosslinker may be an
intercrosslinker, providing intercrosslinking (intercrosslinks)
between flowable microgel particles. The crosslinker may be an
extracrosslinker, providing extracrosslinking (extracrosslinks)
between the flowable microgel particles and a substrate. The
substrate may be tissue. The substrate may be a medical device.
[0057] Generally, crosslinkers disclosed herein comprise at least
two functional groups. The crosslinker may comprise a first
functional group and a second functional group. The first
functional group and the second functional group may be the same.
The first functional group and the second functional group may be
different. Crosslinkers disclosed herein may also be referred to as
multifunctionalized crosslinkers.
[0058] Crosslinkers may be degradable. Crosslinkers disclosed
herein may comprise a peptide. Crosslinkers disclosed herein may
comprise an amino acid. Crosslinkers may comprise a non-peptide
polymer. Degradable crosslinkers may also be random sequences, Omi
target sequences, Heat-Shock Protein target sequences. The
crosslinker may comprise an amino acid having D chirality. The
crosslinker may comprise an amino acid having L chirality.
Crosslinkers may comprise hydrolytically degradable natural and
synthetic polymers consisting of the same backbones listed above
(e.g., heparin, alginate, poly(ethyleneglycol), polyacrylamides,
polymethacrylates, copolymers and terpolymers of the listed
polycondensates, such as polyesters, polyamides, and other
polymers, such as polyurethanes). The crosslinker may be
synthetically manufactured or naturally isolated. The crosslinker
may comprise DNA oligonucleotides with sequences corresponding to:
restriction enzyme recognition sequences, CpG motifs, Zinc finger
motifs, CRISPR or Cas-9 sequences, Talon recognition sequences, and
transcription factor-binding domains. The crosslinker may be
activated on at least two ends by a reactive group, defined as a
chemical group allowing the crosslinker to participate in the
crosslinking reaction to form a polymer network or gel
(intracrosslinking within particles) or to anneal particles
together (intercrosslinking between particles) or to anneal the
particles to a substrate (extracrosslinking between particles and a
substrate), where these functionalities can include: cysteine amino
acids, synthetic and naturally occurring thiol-containing
molecules, carbene-containing groups, vinyl-containing groups,
activated esters, acrylates, norborenes, primary amines,
hydrazides, phosphenes, azides, epoxy-containing groups, SANPAH
containing groups, and diazirine containing groups. In some
instances, flowable microgel particles themselves may act as
crosslinkers.
Intracrosslinkers
[0059] In some instances, intracrosslinkers disclosed herein are
crosslinkers that participate in the crosslinking reaction to form
a polymer network or gel or microgel. In some instances,
intracrosslinkers disclosed herein are crosslinkers that
participate in the crosslinking reaction to form microgel
particles. Often, the intracrosslinker is functionalized with two
or more functional groups. By way of non-limiting example, the
functional groups of the intracrosslinker may be selected from a
vinyl sulfone, a thiol, an amine, an imidazole, an aldehyde, a
ketone, a hydroxyl, an azide, an alkyne, a vinyl, an alkene, a
maleimide, a carboxyl, a N-Hydroxysuccinimide (NHS) ester, an
isocyanate, an isothiocyanate, ahydroxylamine, and a thione. The
intracrosslinker may be homofunctional (same functional groups) or
heterofunctional (different functional groups). Examples of
crosslinking reactions carried out by intracrosslinker include, but
are not limited to, Michael addition, amide bond coupling, "click"
chemistry (e.g. Diels-Alder cycloaddition, Huisgen 1,3-dipolar
cycloaddition), reductive amination, carbamate linkage, ester
linkage, thioether linkage, disulfide bond, hydrazone bond, oxime
coupling, thiourea coupling. By way of non-limiting example, an
intracrosslinker may be a matrix metalloprotease (MMP)-degradable
crosslinker. Examples of MMP-degradable crosslinkers are
synthetically manufactured or naturally isolated peptides with
sequences corresponding to MMP-1 target substrate, MMP-2 target
substrate, MMP-9 target substrates. An intracrosslinker may be a
dithiol-poly(ethylene glycol). An intracrosslinker may be a
diamine-poly(ethylene glycol). An intracrosslinker may be a
diamine-poly(ethylene glycol). An intracrosslinker may be a
4-ARM-poly(ethylene glycol)-thiol. An intracrosslinker may be a
4-ARM-poly(ethylene glycol)-vinyl sulfone. An intracrosslinker may
be a 8-ARM-poly(ethylene glycol)-thiol. An intracrosslinker may be
a 8-ARM-poly(ethylene glycol)-vinyl sulfone.
Intercrosslinkers
[0060] In some instances, intercrosslinkers disclosed herein that
participate in the crosslinking reaction between particles to
anneal particles together. Often, the intercrosslinker is
functionalized with two or more functional groups. By way of
non-limiting example, the functional groups of the intercrosslinker
may be selected from a vinyl sulfone, a thiol, an amine, an
imidazole, an aldehyde, a ketone, a hydroxyl, an azide, an alkyne,
a vinyl, an alkene, a maleimide, a carboxyl, a N-Hydroxysuccinimide
(NHS) ester, an isocyanate, an isothiocyanate, ahydroxylamine, and
a thione. The multifunctionalized crosslinker may be homofunctional
(combination of same functional groups) or heterofunctional
(combination of different functional groups). Examples of
crosslinking reactions carried out by intercrosslinker include, but
are not limited to, Michael addition, amide bond coupling, "click"
chemistry (e.g. Diels-Alder cycloaddition, Huisgen 1,3-dipolar
cycloaddition), reductive amination, carbamate linkage, ester
linkage, thioether linkage, disulfide bond, hydrazone bond, oxime
coupling, thiourea coupling. An intercrosslinker may be a
dithiol-poly(ethylene glycol). An intercrosslinker may be a
diamine-poly(ethylene glycol). An intercrosslinker may be a
dithiol-oligo(ethylene glycol). An intercrosslinker may be a
diamine-oligo(ethylene glycol). An intercrosslinker may be an
ethylenediamine. An intercrosslinker may be a butylenediamine.
Extracrosslinkers
[0061] In some instances, extracrosslinkers disclosed herein
participate in the crosslinking reaction between particles and a
substrate (particle-substrate annealing). By way of non-limiting
example, the functional groups of the extracrosslinker may be
selected from a vinyl sulfone, a thiol, an amine, an imidazole, an
aldehyde, a ketone, a hydroxyl, an azide, an alkyne, a vinyl, an
alkene, a maleimide, a carboxyl, a N-Hydroxysuccinimide (NHS)
ester, an isocyanate, an isothiocyanate, ahydroxylamine, and a
thione. The extracrosslinker may be homofunctional (same functional
groups) or heterofunctional (different functional groups). Examples
of crosslinking reactions carried out by extracrosslinkers
disclosed herein include, but are not limited to, Michael addition,
amide bond coupling, "click" chemistry (e.g. Diels-Alder
cycloaddition, Huisgen 1,3-dipolar cycloaddition), reductive
amination, carbamate linkage, ester linkage, thioether linkage,
disulfide bond, hydrazone bond, oxime coupling, thiourea coupling.
By way of non-limiting example, an extracrosslinker may be a matrix
metalloprotease (MMP)-degradable crosslinker. Examples of
MMP-degradable crosslinkers are synthetically manufactured or
naturally isolated peptides with sequences corresponding to MMP-1
target substrate, MMP-2 target substrate, MMP-9 target substrates.
An extracrosslinker may be a dithiol-poly(ethylene glycol). An
extracrosslinker may be a diamine-poly(ethylene glycol). An
extracrosslinker may be a diamine-poly(ethylene glycol). An
extracrosslinker may be a 4-ARM-poly(ethylene glycol)-thiol. An
extracrosslinker may be a 4-ARM-poly(ethylene glycol)-vinyl
sulfone. An intracrosslinker may be a 8-ARM-poly(ethylene
glycol)-thiol. An extracrosslinker may be a 8-ARM-poly(ethylene
glycol)-vinyl sulfone.
Annealing Agents
[0062] Provided herein are microporous gel systems comprising at
least one annealing agent disclosed herein. The annealing agent may
be a crosslinking agent disclosed herein. The annealing agent may
comprise a photoinitiator. By way of non-limiting example, the
photoinitiator may be Eosin Y. The annealing agent may be
triethanolamine. The annealing agent may be a transglutaminase
enzyme. The annealing agent may be enzyme Factor XIII. The
annealing agent may comprise a free radical transfer agent. The
annealing agent may comprise an electron transfer agent. Examples
of additional and alternative annealing agents, by way of
non-limiting example, include active esters and nucleophiles,
catechols that crosslink upon oxidation, and other redox sensitive
molecules.
Crosslinking Agents
[0063] Microporous gel systems may comprise a crosslinking agent.
The crosslinking agent may be an intracrosslinking agent for
providing intracrosslinks within flowable microgel particles. In
general, intracrosslinking agents do not form crosslinks (e.g.,
they are not part of the bonds), but instead initiate
intracrosslinking reactions between intracrosslinkers. The
crosslinking agent may be an intercrosslinking agent for providing
intercrosslinks between flowable microgel particles. The
crosslinking agent may be an extracrosslinking agent for providing
extracrosslinks between flowable microgel particles and a
substrate. A crosslinking agent may comprise a reducing agent.
Non-limiting examples of reducing agents are dithiothreitol,
dithioerythritol, L-glutathione, and tris (2-carboxyethyl)
phosphine hydrochloride. Crosslinking agents disclosed herein may
comprise an oxidizing agent. Non-limiting examples of oxidizing
agents are horseradish peroxidase (HRP), sodium periodate, and
silver nitrate. Crosslinking agents disclosed herein may comprise a
metal complexing agent. Crosslinking agents disclosed herein may
comprise a catalyst. The crosslinking agent may be a base.
Non-limiting examples of bases are triethylamine, triethanolamine,
4-dimethylaminopyridine, triphenylphosphine. The crosslinking agent
may induce self-crosslinking of the annealing components present on
the flowable microgel particles. Resulting crosslinkages, by way of
non-limiting example, may comprise at least one of a covalent bond,
a coordination complex, a hydrogen bond, an electrostatic
interaction, a cation-.pi. interaction, a .pi.-.pi. stacking, and a
van der Waals interaction.
Cell Adhesive Peptides
[0064] Microporous gel systems may comprise a cell adhesive peptide
disclosed herein. The flowable microgel particles may comprise a
cell adhesive peptide. The cell adhesive peptide may be any peptide
that promotes adherence of a cell to the microgel particles. The
cell adhesive peptide may be at least a portion of an extracellular
matrix protein. The cell adhesive peptide may be at least a portion
of a collagen. The cell adhesive peptide may be at least a portion
of a fibronectin. The cell adhesive peptide may be an integrin. The
cell adhesive peptide may be a ligand to a receptor expressed on
the cell. The cell adhesive peptide may be a cluster of
differentiation (CD) protein. The cell adhesive peptide may be a
naturally-occurring peptide. The cell adhesive peptide may be a
synthetic peptide. The cell adhesive peptide may be homologous to
the naturally-occurring peptide. The cell adhesive peptide may be
at least about 70% homologous to a naturally-occurring peptide. The
cell adhesive peptide may be at least about 80% homologous to a
naturally-occurring peptide. The cell adhesive peptide may be at
least about 90% homologous to a naturally-occurring peptide. The
cell adhesive peptide may be at least 70% homologous to a
naturally-occurring peptide. The cell adhesive peptide may be at
least 80% homologous to a naturally-occurring peptide. The cell
adhesive peptide may be at least 90% homologous to a
naturally-occurring peptide. The cell adhesive peptide may be on a
surface of the microgel particle. By way of non-limiting example,
the cell adhesive peptide may comprise tripeptide
Arginine-Glycine-Aspartate (RGD). The cell adhesive peptide may
comprise K peptide (K peptide: Ac-FKGGERCG-NH2). The cell adhesive
peptide may comprise Q peptide (Q peptide:
Ac-NQEQVSPLGGERCG-NH2).
Microporous Scaffolds
[0065] As one of skill in the art would understand from the instant
disclosure, microporous gel systems, or components thereof, as
disclosed herein, may be initially fluidic in nature and eventually
become a non-fluidic, microporous scaffold that provide a buffer
between a medical device and a tissue. The non-fluidic, microporous
scaffold may be referred to herein simply as a "microporous
scaffold." The microporous scaffold may be flexible or
compressible, with a foam or sponge-like quality. The microporous
scaffold may be more rigid than a foam or sponge, in order to
provide more support to an implanted medical device. The gel before
annealing may have a compressive modulus (mechanical stiffness) of
about 200-1000 Pa. The gel before annealing may have a compressive
modulus (mechanical stiffness) of about 200-500 Pa. The gel before
annealing may have a compressive modulus (mechanical stiffness) of
about 500-1000 Pa. Once annealed, the gel may have a compressive
modulus of about 1,500 Pa to about 200,000 Pa. Once annealed, the
gel may have a compressive modulus of about 1,500 Pa to about
10,000 Pa. Once annealed, the gel may have a compressive modulus of
about 10,000 Pa to about 50,000 Pa. Once annealed, the gel may have
a compressive modulus of about 50,000 Pa to about 125,000 Pa. Once
annealed, the gel may have a compressive modulus of about 125,000
Pa to about 200,000 Pa.
[0066] The microporous scaffold may be non-fluidic due to reactions
that take place during or after the application of the microporous
gel system components. The reactions may result in production of a
covalent bond between two or more flowable microgel particles. The
reactions may result in production of a covalent bond between two
or more annealing components disclosed herein. Such a microporous
scaffold may be referred to herein as a "stabilized scaffold." By
way of non-limiting example, reactions that may result in a
covalent bond include Michael addition, amide bond coupling,
"click" chemistry reactions (e.g. Diels-Alder cycloaddition,
Huisgen 1,3-dipolar cycloaddition), reductive amination, carbamate
linkage, ester linkage, thioether linkage, oxime coupling, and
thiourea coupling. Alternatively or additionally, reactions may
result in production of a non-covalent bond between two or more
flowable microgel particles. By way of non-limiting example,
reactions that may result in a non-covalent bond include
electrostatic interactions, hydrogen bonding, cation-.pi.,
.pi.-.pi. stacking, metal-ligand binding, and van der Waals
interactions.
[0067] Microporous scaffolds disclosed herein may comprise at least
one of a bond, a linkage, an interaction, a coupling and a
connection between flowable microgel particles. In some instances,
the bond, linkage, interaction, coupling or connection is between
two annealing components. In some instances, the bond, linkage,
interaction or connection is between an annealing component and a
functional group on a backbone polymer of a flowable microgel
particle. In some instances, the bond, linkage, interaction,
coupling or connection is between two functional groups on the
backbone polymers two flowable microgel particles. In some
instances, the bond, linkage, interaction, coupling or connection
is between a crosslinker and a functional group on a backbone
polymer of a flowable microgel particle. In some instances, the
bond, linkage, interaction, coupling or connection is between a
crosslinker and an annealing component. In some instances, the bond
is a covalent bond. In some instances, the bond is a non-covalent
bond. In some instances, the bond is selected from an amide bond,
an imine bond, an ester bond, a C--C bond through Michael addition,
a disulfide bond, a hydrazone bond, a hydrogen bond, and a metal
ligand bond. In some instances, the ester bond comprises a cyclic
boronate ester. In some instances, the linkage is selected from a
carbamate linkage, an ester linkage, and a thioether linkage. In
some instances, the coupling is selected from an oxime coupling,
and a thiourea coupling. In some instances, the interaction is
selected from an electrostatic interaction and a van der Waals
interaction. In some instances, the bond, linkage, interaction,
coupling or connection is a result of a reaction between two
functional groups. Non-limiting examples of such functional groups
include a vinyl sulfone, a thiol, an amine, an imidazole, an
aldehyde, a ketone, a hydroxyl, an azide, an alkyne, a vinyl, an
alkene, a maleimide, a carboxyl, a N-Hydroxysuccinimide (NHS)
ester, an isocyanate, an isothiocyanate, a hydroxylamine, a
thione.
[0068] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy about 10% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy about 20% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy about 30%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy about 40% of the total volume of the stabilized scaffold.
The interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 50% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy about 60% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy about 70%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy 10% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy 20% of the total volume of the stabilized
scaffold. The interstitial spaces within the stabilized scaffold of
microgel particles may occupy 30% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy 40% of the total volume
of the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy 50% of the
total volume of the stabilized scaffold. The interstitial spaces
within the stabilized scaffold of microgel particles may occupy 60%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy 70% of the total volume of the stabilized scaffold.
[0069] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy about 80% to about 70% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy about 75%
to about 70% of the total volume of the stabilized scaffold.
[0070] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy about 5% to about 70% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy about 5%
to about 65% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 5% to about 55% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 5% to
about 50% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 5% to about 45% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 5% to
about 40% of the total volume of the stabilized scaffold.
[0071] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy 5% to 70% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy 5% to 65% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy 5% to 55%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy 5% to 50% of the total volume of the stabilized scaffold.
The interstitial spaces within the stabilized scaffold of microgel
particles may occupy 5% to 45% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy 5% to 40% of the total
volume of the stabilized scaffold.
[0072] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy about 10% to about 80% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy about 10%
to about 75% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 10% to about 70% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 10% to
about 65% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 10% to about 55% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 10% to
about 50% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 10% to about 45% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 10% to
about 40% of the total volume of the stabilized scaffold.
[0073] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy 10% to 80% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy 10% to 75% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy 10% to 70%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy 10% to 65% of the total volume of the stabilized scaffold.
The interstitial spaces within the stabilized scaffold of microgel
particles may occupy 10% to 55% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy 10% to 50% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy 10% to 45%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy 10% to 40% of the total volume of the stabilized
scaffold.
[0074] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy about 15% to about 80% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy about 15%
to about 75% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 15% to about 70% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 15% to
about 65% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 15% to about 55% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 15% to
about 50% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 15% to about 45% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 15% to
about 40% of the total volume of the stabilized scaffold.
[0075] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy 15% to 80% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy 15% to 75% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy 15% to 70%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy 15% to 65% of the total volume of the stabilized scaffold.
The interstitial spaces within the stabilized scaffold of microgel
particles may occupy 15% to 55% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy 15% to 50% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy 15% to 45%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy 15% to 40% of the total volume of the stabilized
scaffold.
[0076] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy about 20% to about 80% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy about 20%
to about 75% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 20% to about 70% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 20% to
about 65% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 20% to about 55% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 20% to
about 50% of the total volume of the stabilized scaffold. The
interstitial spaces within the stabilized scaffold of microgel
particles may occupy about 20% to about 45% of the total volume of
the stabilized scaffold. The interstitial spaces within the
stabilized scaffold of microgel particles may occupy about 20% to
about 40% of the total volume of the stabilized scaffold.
[0077] The interstitial spaces within the stabilized scaffold of
microgel particles may occupy 20% to 80% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy 20% to 75% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy 20% to 70%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy 20% to 65% of the total volume of the stabilized scaffold.
The interstitial spaces within the stabilized scaffold of microgel
particles may occupy 20% to 55% of the total volume of the
stabilized scaffold. The interstitial spaces within the stabilized
scaffold of microgel particles may occupy 20% to 50% of the total
volume of the stabilized scaffold. The interstitial spaces within
the stabilized scaffold of microgel particles may occupy 20% to 45%
of the total volume of the stabilized scaffold. The interstitial
spaces within the stabilized scaffold of microgel particles may
occupy 20% to 40% of the total volume of the stabilized
scaffold.
Microporous Gel System Stability
[0078] The microporous gel systems disclosed herein may have a
shelf life of at least about six months. The microporous gel
systems disclosed herein may have a shelf life of at least about
seven months. The microporous gel systems disclosed herein may have
a shelf life of at least about eight months. The microporous gel
systems disclosed herein may have a shelf life of at least about
nine months. The microporous gel systems disclosed herein may have
a shelf life of at least about ten months. The microporous gel
systems disclosed herein may have a shelf life of at least about
eleven months. The microporous gel systems disclosed herein may
have a shelf life of at least about one year. The microporous gel
systems disclosed herein may have a shelf life of at least about
fourteen months. The microporous gel systems disclosed herein may
have a shelf life of at least about sixteen months. The microporous
gel systems disclosed herein may have a shelf life of at least
about eighteen months. The microporous gel systems disclosed herein
may have a shelf life of at least about twenty months. The
microporous gel systems disclosed herein may have a shelf life of
at least about twenty-two months. The microporous gel systems
disclosed herein may have a shelf life of at least about two years.
The microporous gel systems disclosed herein may have a shelf life
of at least about three years. The microporous gel systems
disclosed herein may have a shelf life of at least about four
years. The microporous gel systems disclosed herein may have a
shelf life of at least about five years. The microporous gel
systems disclosed herein may have a shelf life of at least six
months. The microporous gel systems disclosed herein may have a
shelf life of at least seven months. The microporous gel systems
disclosed herein may have a shelf life of at least eight months.
The microporous gel systems disclosed herein may have a shelf life
of at least nine months. The microporous gel systems disclosed
herein may have a shelf life of at least ten months. The
microporous gel systems disclosed herein may have a shelf life of
at least eleven months. The microporous gel systems disclosed
herein may have a shelf life of at least one year. The microporous
gel systems disclosed herein may have a shelf life of at least
fourteen months. The microporous gel systems disclosed herein may
have a shelf life of at least sixteen months. The microporous gel
systems disclosed herein may have a shelf life of at least eighteen
months. The microporous gel systems disclosed herein may have a
shelf life of at least twenty months. The microporous gel systems
disclosed herein may have a shelf life of at least twenty-two
months. The microporous gel systems disclosed herein may have a
shelf life of at least two years. The microporous gel systems
disclosed herein may have a shelf life of at least three years. The
microporous gel systems disclosed herein may have a shelf life of
at least four years. The microporous gel systems disclosed herein
may have a shelf life of at least five years.
[0079] The microporous gel systems disclosed herein, or components
thereof, may be stable (e.g., have a shelf life) up to a
temperature disclosed herein. The microporous gel systems disclosed
herein, or components thereof, may be stable at up to a temperature
when in a dissolved state, a fluidic state, a lyophilized state, or
a dehydrated state. The microporous gel systems, or components
thereof, may be stable at room temperature (about 25.degree. C.).
The microporous gel systems, or components thereof, may be stable
at 25.degree. C. The microporous gel systems, or components
thereof, may be stable at about 25.degree. C. to about 35.degree.
C. The microporous gel systems, or components thereof, may be
stable at 25.degree. C. to 35.degree. C. The microporous gel
systems, or components thereof, may be stable up to about
35.degree. C., up to about 40.degree. C., up to about 45.degree.
C., up to about 50.degree. C., up to about 55.degree. C., up to
about 60.degree. C., up to about 65.degree. C., up to about
70.degree. C., up to about 75.degree. C., up to about 80.degree.
C., up to about 85.degree. C., up to about 90.degree. C., up to
about 95.degree. C., up to about 100.degree. C., up to about
105.degree. C., up to about 110.degree. C., up to about 115.degree.
C., up to about 120.degree. C., up to about 125.degree. C., up to
about 130.degree. C., up to about 135.degree. C., up to about
140.degree. C., up to about 145.degree. C., or up to about
150.degree. C. The microporous gel systems, or components thereof,
may be stable up to 35.degree. C., up to 40.degree. C., up to
45.degree. C., up to 50.degree. C., up to 55.degree. C., up to
60.degree. C., up to 65.degree. C., up to 70.degree. C., up to
75.degree. C., up to 80.degree. C., up to 85.degree. C., up to
90.degree. C., up to 95.degree. C., up to 100.degree. C., up to
105.degree. C., up to 110.degree. C., up to 115.degree. C., up to
120.degree. C., up to 125.degree. C., up to 130.degree. C., up to
135.degree. C., up to 140.degree. C., up to 145.degree. C., or up
to 150.degree. C.
[0080] In some instances the stability or shelf life of the
microporous gel system is increased by storing the microporous gel
system, or a component thereof, below room temperature. Below room
temperature may be about 20.degree. C. to about -80.degree. C.,
about 20.degree. C. to about -20.degree. C., about 20.degree. C. to
about 0.degree. C., or about 20.degree. C. to about 4.degree. C.
Below room temperature may be 20.degree. C. to -80.degree. C.,
20.degree. C. to -20.degree. C., 20.degree. C. to 0.degree. C., or
20.degree. C. to 4.degree. C.
[0081] The microporous gel systems disclosed herein may have a
shelf life of at least about one year at about 25.degree. C. The
microporous gel systems disclosed herein may have a shelf life of
at least about one year at about 4.degree. C. The microporous gel
systems disclosed herein may have a shelf life of at least about
one year at about 25.degree. C. to about 35.degree. C. The
microporous gel systems disclosed herein may have a shelf life of
at least about one year at about 4.degree. C. to about 35.degree.
C. The microporous gel systems disclosed herein may have a shelf
life of at least one year at 25.degree. C. The microporous gel
systems disclosed herein may have a shelf life of at least one year
at 4.degree. C. The microporous gel systems disclosed herein may
have a shelf life of at least one year at 25.degree. C. to
35.degree. C. The microporous gel systems disclosed herein may have
a shelf life of at least one year at 4.degree. C. to 35.degree.
C.
Medical Devices
[0082] Provided herein are methods and systems for treating a
condition in a subject in need thereof, comprising administering to
the subject a medical device disclosed herein. The medical device
may be administered to a site in the subject before, after or
simultaneously with application of a microporous gel system
disclosed herein. The medical device may at least partially contain
the microporous gel system. The medical device may be coated with
the microporous gel system. Medical devices of many different
shapes and sizes will be compatible with the microporous gel
systems and stabilized scaffolds disclosed herein. Due to the
initial fluidic nature of the microporous gel systems disclosed
herein, the microporous gel system can coat portions or shapes of
various medical devices before it becomes a stabilized scaffold. In
some aspects, the stabilized scaffold is conformed to the shape and
size of the device. In some aspects, the stabilized scaffold is
adapted to the shape and size of the device. For the same reason
that the microporous gel system is compatible with medical devices
of many shapes and sizes (e.g., its fluidic nature), it is also
compatible with implant sites of various shapes and sizes. Thus,
the microporous gel system can adapt to, conform to, or custom fill
various implant sites before it becomes the stabilized
scaffold.
[0083] The medical device may be an implant. The implant may be a
temporary implant. A temporary implant may be an implant that
remains in the subject for more than one day, but not more than one
week. A temporary implant may be an implant that remains in the
subject for more than one week, but not more than one month. The
implant may be a permanent implant. The implant may be an organ,
artificial or donor. The implant may be a biomaterial, such as a
mesh or fabric. The implant may be a printed device or tissue. As
used herein, an implant is a medical device that is administered to
a subject that remains in the subject after administration. The
implant may be functional due to its physical structure. The
implant may be functional due to an active function that it
performs. The implant may comprise a glucose sensor. The implant
may comprise a glucose dispenser. The implant may comprise a
cell-based therapy delivered in a device (e.g., an islet cell
transplantation).
[0084] The medical device may be a surgical device. As used herein,
a surgical device is a structure that is used in the subject during
a procedure, and that does not remain in the subject after the
procedure. By way of non-limiting example, the surgical device may
be a laser, scalpel or needle. The procedure may be a surgical
procedure. The surgical procedure may comprise a modification of a
tissue of the subject. The modification may comprise cutting the
tissue. The procedure may be a non-surgical procedure. By way of
non-limiting example, the non-surgical procedure may comprise
insertion of a catheter or application of an ostomy device.
[0085] The medical device may be a vascular stent. The medical
device may be a prosthetic device. The medical device may be an
orthopedic implant, such as an artificial knee, meniscus, hip,
elbow or portion thereof. The medical device may be a dental
implant. The medical device may be a breast implant. The medical
device may be a spinal implant, such as a screw, rod or artificial
disc. The medical device may be an intra-uterine device. The
medical device may be an ear tube. The medical device may be an
artificial eye lens.
[0086] Provided herein are methods and systems for treating a heart
arrhythmia in a subject in need thereof, comprising administering
to the subject a Cardiac Implantable Electronic Device (CIED) and a
microporous gel system disclosed herein. The CIED may be a device
that is capable of correcting or improving an abnormal heart
rhythm. CIEDs may include, but are not limited to, cardiac
pacemakers and implantable cardioverter defibrillators.
[0087] Provided herein are methods and systems for treating a
condition in a subject in need thereof, comprising administering to
the subject a Neural Implantable Electronic Device (NIED), and a
microporous gel system disclosed herein. NIEDs include, but are not
limited to, a neural implant, a brain implant, and a spinal
implant. The implant may also be referred to as neural stimulator
or prosthetic. The microporous scaffolds disclosed herein may
provide an interface between the NIED and a neuron or a brain. The
microporous scaffolds disclosed herein may provide an interface
between the NIED and subcutaneous or connective tissue. The NIED
may comprise an electrode. NIEDs may include, but are not limited
to computer chips, an electro echocardiogram array, a spinal cord
stimulator. The NIED may be a device that produces a deep brain
stimulation. The NIED may be a device that produces a vagus nerve
stimulation. The NIED may be a neuroimaging device or a
neurological activity recording device. The NIED may be a brainstem
implant. The NIED may be a device that is placed in or on a brain.
The NIED may be placed in a sensory organ (e.g., ear, eye, nose,
brain, skin). The NIED may be placed in a spine or brain stem of a
subject. The NIED may be a device that is placed in or on an eye.
The NIED may be a device that is placed in or on an ear, such as a
cochlear implant, by way of non-limiting example. The NIED may
comprise a computer chip. The microporous scaffolds disclosed
herein may provide an interface between the computer chip and a
neuron or a brain (brain-computer interface). The NIED may be a
device that stimulates, blocks or records signals from neurons. The
NIED may be a device that re-wires the brain or re-wires neurons in
the subject. Re-wiring may comprise forming or blocking a neural
synapse.
[0088] The medical devices disclosed herein may be connected to a
computer or in communication with a computer. The medical devices
disclosed herein may be battery operated. The medical devices
disclosed herein may be connected or in communication with a
recording device, a stimulating device, an electrical device, a
power source, a computer, a controller, or any combination
thereof.
[0089] Medical devices disclosed herein may comprise a coating. In
some instances, medical devices disclosed herein do not comprise a
coating. In some instances, medical devices disclosed herein are
pre-coated with a coating. In some instances, the coating comprises
a coating functional group that acts as an annealing component. In
some instances, the coating comprises a coating functional group
that is capable of binding a flowable microgel particle disclosed
herein. In some instances, some instances, the coating comprises a
coating functional group that is capable of reacting with a
flowable microgel particle disclosed herein. In some instances, the
coating comprises a coating functional group that is capable of
binding an annealing component disclosed herein. In some instances,
the coating comprises a coating functional group that is capable of
reacting with an annealing component disclosed herein. In some
instances, the coating comprises a coating functional group that is
capable of binding a crosslinker disclosed herein. In some
instances, the coating comprises a coating functional group that is
capable of reacting with a crosslinker disclosed herein. In some
instances, the coating functional group is an annealing component.
The functional group may become a part of an extracrosslink between
the medical device and the flowable microgel particle.
[0090] Systems disclosed herein may comprise a device coating
agent, wherein the device coating agent enables coating of the
microporous gel system to the medical device. The systems disclosed
herein may comprise a device coating agent, wherein the device
coating agent promotes coating of the microporous gel system to the
medical device. The systems disclosed herein may comprise a device
coating agent, wherein the device coating agent enables adhesion of
the microporous gel system to the medical device. The systems
disclosed herein may comprise a device coating agent, wherein the
device coating agent promotes adhesion of the microporous gel
system scaffold to the medical device.
[0091] Systems disclosed herein may comprise a device coating
agent, wherein the device coating agent enables adhesion of the
stabilized scaffold to the medical device. The systems disclosed
herein may comprise a device coating agent, wherein the device
coating agent promotes adhesion of the stabilized scaffold to the
medical device. The device coating agent may be applied to the
medical device. The device coating agent may be a component of the
microporous gel system. The device coating agent may be mixed with
the microporous gel system or component thereof, prior to use. The
device coating agent may comprise a ceramic, also referred to in
the art as a bioceramic or a bioglass. The device coating agent may
comprise a polymer. The polymer may comprise polyethylene glycol.
The polymer may comprise a polyvinyl group. The polymer may
comprise a parylene. The polymer may comprise a
poly-N-vinylpyrrolidone) (PNP). The polymer may comprise a
polyurethane. The polymer may comprise hyaluronan or hyaluronic
acid.
Therapeutic Agents
[0092] Provided herein are systems comprising a therapeutic agent
disclosed herein. Non-limiting examples of therapeutic agents are
anti-inflammatory agents, antimicrobial agents, and analgesics. The
therapeutic agent may be incorporated in the flowable microgel
particles. The therapeutic agent may be incorporated in the
flowable microgel particles before forming the stabilized scaffold.
The therapeutic agent may be mixed with the flowable microgel
particles and/or annealing agent before forming the stabilized
scaffold. The therapeutic agent may be incorporated in the
stabilized scaffold after forming the stabilized scaffold. The
therapeutic agent may be released from the stabilized scaffold into
or on to the site or tissue of the subject. For example, the
therapeutic agent may be incorporated in the stabilized scaffold
and released as the stabilized scaffold is degraded in the tissue
or as the stabilized scaffold is infiltrated by cells of the tissue
or subject. The therapeutic agent may be released either by an
internal trigger such as tissue mediated and/or enzyme mediated
hydrolysis, hydrolysis not mediated by tissue or enzymes,
enzymolysis, redox change, temperature change or by an external
trigger such as light, electromagnetic field, ultrasound.
Alternatively or additionally, the system may comprise a
therapeutic agent. The therapeutic agent may be released from the
stabilized scaffold by addition of therapeutic agent-releasing
agent. The therapeutic agent may be connected to or contained
within a nanoparticle or nanoparticle system disclosed herein. In
some instances, the medical device comprises a therapeutic agent
disclosed herein. Systems disclosed herein may comprise a single
therapeutic agent or a combination of a plurality of therapeutic
agents.
[0093] Provided herein are systems comprising a therapeutic agent,
wherein the therapeutic agent is incorporated in the stabilized
scaffold and released from the stabilized scaffold. In certain
embodiments, the therapeutic agent is released from the stabilized
scaffold at more than one rate, see, e.g., FIG. 3. In certain
embodiments, the therapeutic agent is actively released. In some
embodiments, the therapeutic agent is passively released, also
referred to as "diffused." The therapeutic agent may be released in
less than about one day. The therapeutic agent may be released in
less than about a week. The therapeutic agent may be released in
less than about one month. The therapeutic agent may be released in
less than one day. The therapeutic agent may be released in less
than a week. The therapeutic agent may be released in less than one
month. At least a portion of the therapeutic agent may be released
in less than about one day. A least a portion of the therapeutic
agent may be released in less than about one week. At least a
portion of the therapeutic agent may be released in less than about
one month. At least a portion of the therapeutic agent may be
released in less than one day. At least a portion of the
therapeutic agent may be released in less than one week. At least a
portion of the therapeutic agent may be released in less than one
month. The therapeutic agent may be released from the stabilized
scaffold over a period of about 1 day to about 1 week. The
therapeutic agent may be released from the stabilized scaffold over
a period of about 1 day to about 2 weeks. The therapeutic agent may
be released from the stabilized scaffold over a period of about 1
day to about 3 weeks. The therapeutic agent may be released from
the stabilized scaffold over a period of about 1 day to about 100
days. At least a portion of the therapeutic agent may be released
over a period of about 1 day to about 100 days. The therapeutic
agent may be released from the stabilized scaffold over a period of
1 day to 1 week. The therapeutic agent may be released from the
stabilized scaffold over a period of 1 day to 2 weeks. The
therapeutic agent may be released from the stabilized scaffold over
a period of 1 day to 3 weeks. The therapeutic agent may be released
from the stabilized scaffold over a period of 1 day to 100 days. At
least a portion of the therapeutic agent may be released over a
period of 1 day to 100 days. The portion of the therapeutic agent
may be about 1% to about 50% of the therapeutic agent. The portion
of the therapeutic agent may be about 10% to about 50% of the
therapeutic agent. The portion of the therapeutic agent may be
about 10% to about 80% of the therapeutic agent. The portion of the
therapeutic agent may be about 1% to about 10%. The portion of the
therapeutic agent may be 1% to 50% of the therapeutic agent. The
portion of the therapeutic agent may be 10% to 50% of the
therapeutic agent. The portion of the therapeutic agent may be 10%
to 80% of the therapeutic agent. The portion of the therapeutic
agent may be 1% to 10%.
[0094] The therapeutic agent may be present in the microporous gel
system at a concentration of about 1 .mu.g/mL to about 1 mg/mL. The
therapeutic agent may be present in the microporous gel system at a
concentration of about 1 .mu.g/mL, about 5 .mu.g/mL, about 10
.mu.g/mL, about 20 .mu.g/mL, about 30 .mu.g/mL, about 40 .mu.g/mL,
about 50 .mu.g/mL, about 60 .mu.g/mL, about 70 .mu.g/mL, about 80
.mu.g/mL, about 90 .mu.g/mL, or about 100 .mu.g/mL. The therapeutic
agent may be present in the microporous gel system at a
concentration of about 100 .mu.g/mL, about 200 .mu.g/mL, about 300
.mu.g/mL, about 400 .mu.g/mL, about 500 .mu.g/mL, about 600
.mu.g/mL, about 700 .mu.g/mL, about 800 .mu.g/mL, about 900
.mu.g/mL, or about 1 mg/mL. The therapeutic agent may be present in
the microporous gel system at a concentration of about 1 mg/mL to
about 10 mg/mL. The therapeutic agent may be present in the
microporous gel system at a concentration of about 10 mg/mL to
about 350 mg/mL. The therapeutic agent may be present in the
microporous gel system at a concentration of about 50 mg/mL to
about 300 mg/mL. The therapeutic agent may be present in the
microporous gel system at a concentration of about 5 mg/mL, about
10 mg/mL, about 20 mg/mL, about 40 mg/mL, about 60 mg/mL, about 80
mg/mL, about 100 mg/mL, about 150 mg/mL, about 200 mg/mL, about 250
mg/mL, about 300 mg/mL, about 350 mg/mL, or about 400 mg/mL. The
therapeutic agent may be present in the microporous gel system at a
concentration of 1 .mu.g/mL to 1 mg/mL. The therapeutic agent may
be present in the microporous gel system at a concentration of 1
.mu.g/mL, 5 .mu.g/mL, 10 .mu.g/mL, 20 .mu.g/mL, 30 .mu.g/mL, 40
.mu.g/mL, 50 .mu.g/mL, 60 .mu.g/mL, 70 .mu.g/mL, 80 .mu.g/mL, 90
.mu.g/mL, or 100 .mu.g/mL. The therapeutic agent may be present in
the microporous gel system at a concentration of 100 .mu.g/mL, 200
.mu.g/mL, 300 .mu.g/mL, 400 .mu.g/mL, 500 .mu.g/mL, 600 .mu.g/mL,
700 .mu.g/mL, 800 .mu.g/mL, 900 .mu.g/mL, or 1 mg/mL. The
therapeutic agent may be present in the microporous gel system at a
concentration of 1 mg/mL to 10 mg/mL. The therapeutic agent may be
present in the microporous gel system at a concentration of 10
mg/mL to 350 mg/mL. The therapeutic agent may be present in the
microporous gel system at a concentration of 50 mg/mL to 300 mg/mL.
The therapeutic agent may be present in the microporous gel system
at a concentration of 5 mg/mL, 10 mg/mL, 20 mg/mL, 40 mg/mL, 60
mg/mL, 80 mg/mL, 100 mg/mL, 150 mg/mL, 200 mg/mL, 250 mg/mL, 300
mg/mL, 350 mg/mL, or 400 mg/mL.
[0095] Provided herein are systems and methods that comprise
anti-inflammatory agents, combinations thereof, and uses thereof.
The anti-inflammatory agent may be a steroidal or hormonal agent.
The anti-inflammatory agent may be a non-steroidal
anti-inflammatory agent. The anti-inflammatory agent may be
synthetic or non-naturally-occurring. The anti-inflammatory agent
may be naturally-occurring. By way of non-limiting example, the
anti-inflammatory agent may be ibuprofen, aspirin, natural or
synthetic corticosteriods, an anti-inflammatory neuropeptide
.alpha.-melanocyte stimulating hormone (.alpha.-MSH),
dexamethasone, or meloxicam, or combinations thereof.
[0096] Provided herein are systems and methods that comprise
antimicrobial agents, combinations thereof, and uses thereof. The
antimicrobial agent may be an antibacterial agent, also referred to
as an antibiotic. The antimicrobial agent may be selected from an
antibacterial agent, an antifungal agent, an antimycotic agent, an
antiparasitic agent, or an antiseptic agent. By way of non-limiting
example, the antibiotic may be al-lactam (e.g., penam, cephem,
monobactam, carbapenem, penicillin, ceftriaxone), a macrolide
(e.g., erythromycin), an aminoglycoside (e.g., tobramycin,
neomycin, ampicillin, aminopenicillin, amoxicillin, kanamycin), a
glycopeptide antibiotic (e.g., vancomycin), a quinolone (e.g.,
ciprofloxacin levofloxacin, moxifloxacin), a tetracycline, a
phenicol or a sulfonamide.
[0097] Provided herein are systems comprising a combination of
antimicrobial agents. The combination of antimicrobial agents may
comprise a combination of antibiotics. The combination of
antibiotics may be selected from a combination of a .beta.-lactam,
a macrolide, an aminoglycoside, a glycopeptide antibiotic, a
quinolone, a tetracycline, a phenicol, a sulfonamide. The
antibiotic may be present in the microporous gel system or the
stabilized scaffold at a minimal inhibitory concentration. The
antibiotic may be present in the microporous gel system or the
stabilized scaffold at a concentration that is bactericidal at the
implant site or surgical site. The antibiotic may be present in the
microporous gel system or the stabilized scaffold at a
concentration that is bacteriostatic at the implant site or
surgical site.
[0098] Provided herein are systems comprising an antimicrobial
agent, wherein the antimicrobial agent is incorporated in the
stabilized scaffold and released from the stabilized scaffold. The
antimicrobial agent may be released from the stabilized scaffold at
a rate. In certain embodiments, the antimicrobial agent is released
from the stabilized scaffold at more than one rate, see, e.g., FIG.
3. In certain embodiments, the antimicrobial agent is actively
released. In some embodiments, the antimicrobial agent is passively
released, also referred to as "diffused." The antimicrobial agent
may be an antibiotic. The antimicrobial agent may be released over
the period of at least about one week. The antimicrobial agent may
be released over the period of at least about ten days. The
antimicrobial agent may be released over the period of at least
about two weeks. The antimicrobial agent may be released over the
period of at least about three weeks. The antimicrobial agent may
be released over the period of at least about four weeks. The
antimicrobial agent may be released over the period of one week.
The antimicrobial agent may be released over the period of ten
days. The antimicrobial agent may be released over the period of
two weeks. The antimicrobial agent may be released over the period
of three weeks. The antimicrobial agent may be released over the
period of four weeks. The antimicrobial agent may be released at a
rate that reduces or kills microbes at the implant site or surgical
site. The amount of antimicrobial agent, and the rate at which it
is released at the implant site or surgical site, may be considered
bactericidal. The antimicrobial agent may be released at a rate
that maintains microbe presence at the implant site or surgical
site, but prevents growth of microbes at the implant site or
surgical site. The amount of antimicrobial agent, and the rate at
which it is released at the implant site or surgical site, may be
considered bacteriostatic.
[0099] Provided herein are systems that comprise an agent that
prevents, alleviates or reduces pain or discomfort at the implant
site or surgical site. Provided herein are systems and methods that
comprise at least one analgesic, combinations of analgesics, or a
use thereof. By way of non-limiting example, the analgesic may be
paracetamol (also known as acetaminophen), an opioid, a
non-steroidal anti-inflammatory drug (NSAID), a cyclooxygenase
inhibitor, a cannabinoid, a ketamine, and a combination thereof.
Alternatively, or additionally, the systems and methods may
comprise a local anesthetic or a use thereof. By way of
non-limiting example, the local anesthetic may be benzocaine,
chloroprocaine, cyclomethycaine, dimethocaine/larocaine,
piperocaine, propoxycaine, procaine/novocaine, proparacaine,
tetracaine/amethocaine, chloroprocaine, saxitoxin, neosaxitoxin,
tetrodotoxin, menthol, or eugenol, or a combination thereof. In
certain embodiments, the system to method comprises a combination
of the local anesthetic with a vasoconstrictor, or a used thereof.
A non-limiting example of a vasoconstrictor is epinephrine.
Provided herein are therapeutic agents disclosed herein and methods
of incorporating the therapeutic agents into the microporous gel
systems disclosed herein. The therapeutic agent may be directly
incorporated in the microporous gel system disclosed herein. For
example, the therapeutic agent may be loaded into or on to the
microgel particles of the microporous gel system. The therapeutic
agent may be passively loaded into the microporous gel via
diffusion. The therapeutic agent may be passively loaded into the
microporous gel via entrapment. The therapeutic agent may be
directly incorporated in the microporous gel system by a covalent
linkage between the therapeutic agent and a polymer or crosslinker
of the microporous gel system. The therapeutic agent may be
directly incorporated in the microporous gel system by
immobilization of the therapeutic agent via a photo-caging method.
The therapeutic agent may be loaded in a nanoparticle (a
therapeutic agent-loaded nanoparticle). The microporous gel systems
disclosed herein may comprise a mixture of therapeutic agent-loaded
microparticles and therapeutic agent-loaded nanoparticles embedded
into the microgel particles. Methods for incorporating therapeutic
agent-loaded nanoparticles into the microporous gel system may
comprise dissolving lyophilized therapeutic agent-loaded
nanoparticles in an aqueous buffer prior to mixing the therapeutic
agent-loaded nanoparticles with the microporous gel system. Methods
for incorporating therapeutic agent-loaded nanoparticles into the
microporous gel system may comprise directly embedding the
therapeutic agent-loaded nanoparticles into the microgel particles
during the microgel fabrication. The microporous gel systems
disclosed herein may comprise a mixture of therapeutic agent-loaded
microparticles and therapeutic agent-loaded nanoparticles embedded
into the microgel particles.
[0100] Provided herein are systems that comprise a microporous gel
system disclosed herein, wherein the microporous gel system
releases a therapeutic agent disclosed herein into a tissue or
biological fluid of a subject. Release of therapeutic agents may
occur via passive diffusion from the microgel particles and/or
nanoparticles (see, e.g., FIG. 3). Release of therapeutic agents
may occur via an active release. The active release may be
initiated by an external stimulus. The external stimulus, by way of
non-limiting example, may be light (e.g., UV or NIR), a change of
temperature, ultrasound, or a magnetic field. The active release
may be initiated by an internal stimulus. The internal stimulus may
be produced by the subject. The internal stimulus, by way of
non-limiting example, may be a pH change, a redox reaction,
enzymatic activity, or chemical activity.
[0101] Therapeutic agents disclosed herein may be delivered in
nanoparticles. By way of non-limiting example, nanoparticles may
comprise a polymer selected from poly(lactic-co-glycolic acid)
(PLGA) or a copolymer thereof, a poly(anhydride), a poly(amide), a
poly(ortho ester), a polycaprolactone. The nanoparticle may
comprise hyaluronic acid. The nanoparticle may comprise chitosan.
The nanoparticle may be a mesoporous silica nanoparticle. The
nanoparticle may comprise a polymer with a lower critical solution
temperature (LCST), such as poly(N-isopropylacrylamide) (PNIPAm) or
co-polymer of PNIPAm, by way of non-limiting example. The
nanoparticle may comprise a polymer with an upper critical solution
temperature (UCST) such as poly(hydroxyethylmethacrylate) (PHEMA)
or polyethylene oxide (PEO) or
poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide)
(PEO-PPO-PEO). The nanoparticle may comprise a self-immolating
polymer such as poly(p-aminobenzyl oxycarbonyl) (poly(PABC)) that
is capped with a cage that can be released upon a stimulus (e.g.,
light, temperature, pH, redox, enzyme). In self-immolating systems,
a single cleavage event of an end-cap can trigger an entire chain
to degrade into small molecules, allowing the entrapped drug to be
released. For instance, silver nitrate (used as an oxidizing agent)
can be encapsulated into thermosensitive liposomes (made of 90 mol
% dipalmitoyl phosphatidylcholine and 10 mol % of 1-palmitoyl
lysophosphatidylcholine). The silver nitrate-loaded liposomes are
entrapped in DOPA-functionalized microgel particles and are stable
at room temperature. By way of non-limiting example, nanoparticles
may comprise liposomes or lipid vesicles. At body temperature, the
lipid bilayer of the liposomes is more permeable allowing silver
nitrate to be released and oxidize the catechol of the DOPA
moieties into reactive quinones that can further react with another
DOPA group leading to the crosslinking of the DOPA-functionalized
microgel particles.
[0102] Provided herein are systems that comprise a core-shell
nanoparticle system in which the shell responds to a stimulus. The
core or shell may comprise any combination of the materials that
are components of the nanoparticles disclosed herein. This core
shell system may enable the nanoparticles to retain a cargo, such
as a therapeutic agent disclosed herein, while being stored in an
aqueous environment (e.g., inside the microgel solution in a
syringe). The cargo may be released by applying an external
stimulus to the tissue site (e.g., light, electromagnetic
radiation). The cargo may be released by an internal stimulus,
present in a tissue of the subject, (e.g., enzymes, redox
potential, pH, temperature). The microporous gel system may
comprise a first portion of microgel particles and a second portion
of microgel particles, wherein the first portion of microgel
particles comprises the core-shell nanoparticle system, and wherein
the second portion of microgel particles comprises an agent that
dissolves the shell and initiates release of the cargo from the
first portion of microgel particles. The methods disclosed herein
may comprise delivering the first portion and the second portion of
microgel particles simultaneously or sequentially, through a single
or multiple syringes or multi-barrel syringe/cannula/tube
systems.
Methods and Systems for Producing Microporous Gel Systems
[0103] Provided herein are methods and systems for producing
microporous gel systems. One of skill in the art understands that
methods for producing microporous gel systems described herein may
be performed with manufacturing systems comprising reagents and
materials employed by the methods. In some instances, the methods
comprise synthesizing flowable microgel particles. The term
"flowable microgel particle," as described herein, includes a
hydrogel particle. Generally, flowable microgel particles disclosed
herein comprise a high water content and "intra-crosslinks"
(crosslinks within the particles). In general, a high water content
is a water content greater than 50% to up to about 99.9% water. In
some instances, the water content is about 60% to about 99.9%. In
some instances, the water content is about 70% to about 99.9%. The
intra-crosslinks may be physical, chemical, or a combination
thereof.
Synthesis of Flowable Microgel Particles
[0104] The microgel particles may be synthesized using a
microfluidic device (one particle at a time per channel). The
microgel particles may be synthesized by water-in-oil emulsion as
described in greater detail herein. The microgel particles may be
synthesized by water-in-oil emulsion with mechanical stirring. The
microgel particles may be synthesized by water-in-oil emulsion
using a static mixer. The microgel particles may be synthesized
using in-line flow-through synthesis. The microgel particles may be
synthesized using a parallel production method (multiple particles
at a time per channel). Methods of synthesizing flowable microgel
particles disclosed herein are described in further detail
throughout the instant disclosure.
[0105] Methods disclosed herein may comprise synthesizing microgel
particles by a water-in-oil emulsion process. In some instances,
the methods being with obtaining an oil or an oil mixture. By way
of non-limiting example, the oil may be a light mineral oil (LMO)
or a heavy mineral oil (HMO). In some instances, oil mixtures
comprise a surfactant. Different surfactants can be employed. The
surfactant may be a nonionic surfactant. Non-limiting examples of
nonionic surfactants are Span80, Span20, Tween20, Tween40, Tween60,
Tween80, and tocopheryl polyethylene glycol 1000 succinate (TPGS).
The surfactant may be an anionic surfactant. Non-limiting examples
of anionic surfactants are sodium dodecyl sulfate (SDS), sodium
lauryl ether sulfate (SLES), and perfluorooctanesulfonate. The
surfactant may be a cationic surfactant. Non-limiting examples of
cationic surfactants are cetyltrimethylammonium bromide (CTAB), and
hexadecylpyridium bromide. The surfactant may be an amphoteric
surfactant. Non-limiting examples of amphoteric surfactants are
betaine citrate, lauryl betaine, sodium, and (carboxymethyl)
dimethyloleyl ammonium hydroxide. The concentration of the
surfactant may vary from 0.01 to 5% v/v.
[0106] In some instances, methods comprise adding the surfactant to
the oil. In some instances, methods comprise adding the surfactant
to the oil prior to the addition of an aqueous solution/mixture to
the oil. In some instances, methods comprise adding the surfactant
to an aqueous solution/mixture described herein. In some instances,
having a surfactant in the aqueous phase is beneficial because if
the surfactant has a high-water solubility it is easy to remove
during purification.
[0107] The oil or oil mixture may be added to a bioreactor vessel
through a micron filter and stirred. In some instances, the
bioreactor vessel contains a volume from about 100 milliliters to
about 1 liter. In some instances, the bioreactor vessel contains a
volume from about 1 liter to about 10 liters. In some instances,
the bioreactor vessel contains a volume from about 10 liters to
about 100 liters. In some instances, the bioreactor vessel contains
a volume from about 100 liters to about 1000 liters. In some
instances, the bioreactor vessel contains a volume from about 100
liters to about 10,000 liters. In some instances, the bioreactor
vessel contains a volume from about 10 liters to about 1000 liters.
In some instances, the bioreactor vessel contains a volume from
about 1000 liters to about 10,000 liters. In some instances, the
micron filter has a pore size of about 0.1 .mu.m to about 1 .mu.m.
In some instances, the micron filter has a pore size of about 0.2
.mu.m.
[0108] In some instances, methods of synthesizing microgel
particles comprise modifying a backbone polymer. In some instances,
methods comprise attaching one or more functional groups to the
backbone polymer. In some instances, only one functional group is
attached, and the resulting backbone polymer is referred to as a
polymerization monomer. In some instances, two or more functional
groups are attached, and the resulting backbone polymer is referred
to as an intracrosslinking component. The term, "intracrosslinking
component," as used herein, generally refers to molecules that
participate in the formation of the intracrosslinks (they form the
crosslink bonds). In some instances, an intracrosslinking component
is also an intracrosslinker.
[0109] In some instances, methods of synthesizing microgel
particles comprise mixing two or more types of intracrosslinking
components. In some instances, methods of synthesizing microgel
particles comprise mixing two or more types of intracrosslinking
components and an intracrosslinking agent. In some instances,
methods of synthesizing microgel particles comprise mixing an
intracrosslinking component and an intracrosslinking agent. In some
instances, methods of synthesizing microgel particles comprise
mixing a polymerizing agent and a polymerization monomer.
[0110] In some instances, methods comprise obtaining a solution of
at least one of an intracrosslinking component. In some instances,
methods comprise preparing a solution of at least one of an
intracrosslinking component. In some instances, methods comprise
including an intracrosslinking agent in the solution. In other
instances, an intracrosslinking agent is not required because the
intracrosslinking component(s) self-crosslink without a
crosslinking agent. Methods may comprise filtering the solution.
The solution may comprise a backbone polymer. The solution may
comprise a peptide. The solution may comprise a buffer or buffering
agent. The solution may comprise a base catalyst.
[0111] By way of non-limiting example, a solution comprising
backbone polymer: 4-arm poly(ethylene glycol) functionalized with
four vinyl sulfone groups (PEG-VS) and limiting amounts of
K-peptide (Ac-FKGGERCG-NH2), Q-peptide (Ac-NQEQVSPLGGERCG-NH2), and
RGD (Ac-RGDSPGERCG-NH2); may be mixed with MMP-degradable peptide
with thiol-containing cysteines on the N and C termini. Both the
functionalized PEG-VS and MMP-degradable peptide provide
intracrosslinking components; PEG-VS provides four vinyl sulfone
groups and MMP-degradable peptide provides two thiol groups. Upon
mixing of the PEG-VS and MMP-degradable peptide (both
intracrosslinking components) in the presence of triethanolamine, a
base catalyst and intracrosslinking agent, intracrosslinking takes
place and particles are formed. K-peptide (Ac-FKGGERCG-NH2),
Q-peptide (Ac-NQEQVSPLGGERCG-NH2), and RGD (Ac-RGDSPGERCG-NH2);
intracrosslinker; and base catalyst: triethanolamine.
[0112] The concentration of 4-arm poly(ethylene glycol) vinyl
sulfone (PEG-VS) (20 kDa) may be about 5% w/v to about 15% w/v. The
concentration of 4-arm poly(ethylene glycol) vinyl sulfone (PEG-VS)
may be about 10% w/v. The PEG-VS may be PEG-VS (20 kDa). The
concentration of K-peptide may be about 100 .mu.M to about 1 mM.
The concentration of K-peptide may be about 500 .mu.M. The
concentration of Q-peptide may be about 100 .mu.M to about 1 mM.
The concentration of Q-peptide may be about 500 .mu.M. The
concentration of RGD may be about 0.1 mM to about 10 mM. The
concentration of RGD may be about 1 mM. The concentration of
triethanolamine may be about 50 mM to about 500 mM. The
concentration of triethanolamine may be about 300 mM. The pH of
triethanolamine may be about 7 to about 9. The pH of
triethanolamine may be about 7.75.
[0113] In some instances, methods comprise obtaining an
intracrosslinker solution. In some instances, methods comprise
preparing an intracrosslinker solution. The intracrosslinker
solution may comprise a degradable peptide. The intracrosslinker
solution may comprise di-cysteine MMP-sensitive peptide. The
concentration of the intracrosslinker in the intracrosslinker
solution may be about 1 mM to about 50 mM. The concentration of the
intracrosslinker in the intracrosslinker solution may be about 5 mM
to about 15 mM. The method may comprise filtering the
intracrosslinker solution.
[0114] Methods of producing may comprise mixing the
intracrosslinking agent with the crosslinker solution to produce an
aqueous mixture. In some instances, methods comprise adding the
aqueous mixture to the oil in an oil container. In some instances,
methods comprise adding an aqueous mixture to oil at a volume
fraction of the aqueous phase into the oil phase. The volume
fraction may be about 1% to about 10% v/v/w/o. In some instances,
methods comprise injecting the aqueous mixture into the oil.
Injecting may comprise the use of a peristaltic pump. In some
instances, the peristatic pump is operated at about 100 mL/min to
about 200 mL/min. In some instances, the peristatic pump is
operated at about 150 mL/min. In some instances, the peristatic
pump is operated at about 135 mL/min. In some instances injecting
is performed immediately after mixing. The methods may comprise
stirring the oil as the aqueous mixture is added. The speed of
stirring (agitation) may vary from 100-20,000 rpm, depending upon
the size of the reaction vessel and the size of particles needed.
Different impeller types may be used for the agitation (turbine
overhead stirrer, paddle overhead stirrer, blade stirrer, dissolver
stirrer, spiral stirrer, propeller stirrer, double impeller).
Stirring may occur for at least 1 hour. Stirring may occur for at
least 2 hours. Stirring may occur for about 1 hour to about 24
hours. When stirring stops, flowable microgel particles settle to
the bottom of the oil container. The final size of the flowable
microgel particles may be dependent upon the concentrations of the
materials, the speed of stirring, volume fraction, and speed of
injection of the aqueous phase to the oil phase.
[0115] In some instances, the methods may comprise a base-catalyzed
Michael addition. The base may be an amine (e.g. triethanolamine,
trimethylamine), an amidine (e.g. 1,8-diazabicycloundec-7-ene
(DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN)), an imidazole, a
pyridine (e.g. 4-dimethylaminopyridine (DMAP)), an amine (e.g.,
n-pentylamine), a phosphine (e.g. tri-n-propylphosphine,
dimethylphenylphosphine, methyldiphenylphosphine,
triphenylphosphine). In some instances, the base is added to the
oil prior to addition of an aqueous phase to oil. In some
instances, the base is added to a solution disclosed herein prior
to formation of an aqueous mixture. In some instances, it is
beneficial to add the base to the oil because it ensures initiation
of the gelation occurs only when the aqueous mixture is added to
the oil.
[0116] In some instances, methods comprise synthesizing flowable
microgel particles by pumping the aqueous mixture into the oil and
mixing the resulting emulsion with a static mixer connected to a
reaction vessel. The flowable microgel particles that are generated
by the static mixer are collected in the reaction vessel and kept
under gentle agitation until the reaction is complete. In this
method, a base catalyst may be added to the oil to prevent a
gelation reaction from occurring in the aqueous mixture before
particle dispersion in the static mixer. Benefits of using a static
mixer include, but are not limited to the following: gelation may
occur when both phases are in contact in the static mixer; less oil
is required; and a greater particle concentration is obtained.
Thus, large manufacturing scales are achievable.
Purifying Flowable Microgel Particles
[0117] Methods disclosed herein may comprise purifying flowable
microgel particles. In some instances, methods comprise
synthesizing and purifying flowable microgel particles
simultaneously. In some instances, methods comprise purifying
flowable microgel particles after synthesizing the flowable
microgel particles. In some instances, purifying flowable microgel
particles comprises performing membrane separation of the flowable
microgel particles from unwanted components. Different types of
filtration membranes may be used (e.g., hollow fiber membranes with
different pore sizes, different lumen IDs or flat sheet membrane).
In some instances, membrane separation comprises tangential flow
filtration (TFF). In some instances, membrane separation comprises
ultrafiltration-diafiltration (UFDF). In some instances, membrane
separation comprises microfiltration-diafiltration (MFDF).). In
some instances, membrane separation comprises
hollow-fiber-diafiltration (HFDF). TFF generally comprises a
membrane filtration and separation technique. TFF may be used
herein to purify and concentrate flowable microgel particles. TFF
may comprise generating a feed stream of a solution of flowable
microgel particles that passes parallel to a membrane face. One
portion of the solution may pass through the membrane (permeate)
while the remainder (retentate) is recirculated back to the feed
reservoir. This system may be referred to as diafiltration. This
system may allow molecules (in the permeate) smaller than the
membrane pores to move toward and through the membrane while the
larger molecules, such as the flowable microgel particles, remain
in the retentate. In some instances, the flow in the filtration
system may be controlled by a peristaltic pump. In some instances,
the flow in the filtration system may be controlled by a
Quattroflow pump or any positive displacement pump. In some
instances, the filtration system may be closed to surrounding
environment. In some instances, the filtration system may be open
to surrounding environment.
[0118] Methods of purifying may comprise removing excess oil from
the flowable microgel particles. Methods of purifying may comprise
dispersing the particles in an alcohol solution. Methods of
purifying may comprise removing excess oil and surfactant that are
not miscible in water while keeping the particles (mainly composed
of water) dispersed and sufficiently swollen and ensuring no
particle aggregation. Methods of purifying may comprise slowly
transferring the particles into an aqueous buffer while preventing
the surfactant from precipitating. Transferring rate may be linked
to the flux of filtrate passing through the membrane, and occur at
a rate of about 1 to about 1000 LMH (liters/m.sup.2h). Transferring
may occur at a rate of about 100 to about 500 LMH. Transferring may
occur at a rate of about 200 to about 300 LMH. This transition rate
may be particularly important to ensure that a surfactant does not
precipitate on to (and within) the flowable microgel particles,
rendering the particles unsuitable for a microporous scaffold. The
transition rate may achieve at least one of (i) particle hydrogel
mesh swelling, which is a product of the affinity for certain
solvents for a given hydrogel polymer backbone/crosslinker system,
and (ii) solubility of the surfactant in the continuous phase
outside of the particle.
[0119] Methods may comprise ensuring that there is only one
miscible continuous phase to allow TFF to proceed by using an
intermediate solvent (e.g. isopropanol (IPA)) which is miscible
with both mineral oil and water, and capable of substantially
swelling the particle mesh when mixed with either the mineral oil
or the water. This can enable the transfer of the oil-dispersed
particles from the oil into water, while removing surfactant and
finally to an aqueous buffer, while never creating more than one
miscible continuous phase. See, e.g., FIG. 9.
[0120] In some instances, methods comprise performing membrane
filtration or membrane separation to concentrate the flowable
microgel particles to a particle concentration in a solution,
fluid, or solvent described herein. The shear rate occurring on the
inside face of the membrane filter as solution passes by may affect
the capability of concentrated particle suspensions to flow, and
become increasingly difficult to maintain flow at high
concentrations. In some instances, the shear rate may be between 1
s.sup.-1 and 100 s.sup.-1. In some instances, the shear rate may be
between 100 s.sup.-1 and 500 s.sup.-1. In some instances, the shear
rate may be between 500 s.sup.-1 and 1,000 s.sup.-1. In some
instances, the shear rate may be between 1,000 s.sup.-1 and 5,000
s.sup.-1. In some instances, the shear rate may be between 5,000
s.sup.-1 and 10,000 s.sup.-1. The concentration may be about 1% v/v
to about 100% v/v. The concentration may be about 1% v/v to about
10% v/v. The concentration may be about 10% v/v to about 20% v/v.
The concentration may be about 20% v/v to about 30% v/v. The
concentration may be about 30% v/v to about 40% v/v. The
concentration may be about 40% v/v to about 50% v/v. The
concentration may be about 50% v/v to about 60% v/v. The
concentration may be about 60% v/v to about 70% v/v. The
concentration may be about 70% v/v to about 80% v/v. The
concentration may be about 80% v/v to about 90% v/v. The
concentration may be about 90% v/v to about 99% v/v. The
concentration may be about 90% v/v to about 100% v/v. Additionally
or alternatively, flowable microgel particles are concentrated by
centrifugation.
[0121] In some instances, methods comprise contacting the flowable
microgel particles with at least one solvent to purify the
particles. In some instances, methods comprise contacting the
flowable microgel particles with a gradient of solvents. In some
instances, the solvent is selected from an alcohol solution, water,
and an aqueous buffer. In some instances, the solvent is an organic
solvent (including alcohol solutions). Organic solvents may be
suitable for transitioning flowable microgel particles from an oil
phase to an aqueous phase. Organic solvents include, but are not
limited to, isopropyl alcohol (IPA), methanol, ethanol, glycerol,
acetone, acetonitrile, hexane, tetrahydrofuran, and 1,4-dioxane. In
some instances, a combination of various organic solvents can be
used. By way of non-limiting example, a combination of organic
solvents may comprise hexane and IPA. In some instances, the
alcohol solution comprises IPA, also referred to as isopropanol. In
some instances, the alcohol solution consists of IPA and water. In
some instances, the alcohol solution is about 30%, about 35%, about
40%, about 45%, about 50%, about 55%, about 60%, about 65%, about
70%, about 75%, about 80%, about 85%, or about 90% alcohol. In some
instances, the alcohol solution is about 90%, about 92%, about 95%,
about 98%, or about 99% alcohol. In some instances, methods
comprise performing diafiltration with a 95% IPA solution. In some
instances, methods comprise performing diafiltration with a 50% IPA
solution. In some instances, methods comprise performing
diafiltration with 100% pure water. Non-limiting examples of
aqueous buffers include phosphate buffers, HEPES buffers, MES
buffers, Tris buffers, Tricine buffers, PIPES buffers, borate
buffers, MOPS buffers, and combinations thereof. In some instances,
the aqueous buffer has a pH of about 6.6, about 6.0, about 6.2,
about 6.4, about 6.6, about 6.8, about 7.0, about 7.2, about 7.4,
about 7.6, about 7.8, about 8.0, about 8.2, about 8.4, about 8.6,
about 8.8, or about 9.0. By way of non-limiting example, the
aqueous buffer may comprise 10 mM phosphate buffer, 100 mM NaCl,
and 5 .mu.M Eosin Y, with a pH of 7.4.
[0122] In some instances, methods do not comprise initially adding
only water to oil in which the flowable microgel particles are
present. Adding water directly to oil would likely create two
immiscible phases, in which the particles stick at an interface
(along with precipitated surfactant), and foul separation
membranes. In some instances, methods comprise initially adding an
organic solvent and gradually transitioning to water through a
gradient of solutions comprising decreasing amounts of organic
solvent in water. In this way, a single miscible phase is
maintained.
[0123] In some instances, methods of producing microgel particles
comprise producing a mesh of polymers, peptides, or a combination
thereof within the microgel particles. The mesh may be described as
a three dimensional network formed by intracrosslinks within the
microgel particle. The mesh is porous, resulting in pores within
the particles. Pores within the microgel particles are generally
nanoscopic pores, as opposed to the microscopic pores between the
particles. Nanoscopic may be considered to be less than one micron
in its greatest dimension. Microgel particles may swell in size
when they are transitioning from organic solvent into water. Since
the microparticles grow in size when they swell, polymer chains
that make up the microgel particle may unfold in the water, thereby
increasing the spacing within the 3D network (the mesh) and
increasing the space between each neighboring polymer in the mesh
(the pore size).
Annealing Flowable Microgel Particles
[0124] In some instances, the methods comprise annealing two or
more flowable microgel particles together. This may be referred to
as particle-particle annealing. Particle-particle annealing
includes intercrosslinking. In some instances, annealing results in
formation of at least one bond. In some instances, the bond is a
covalent bond. Non-limiting examples of a covalent bond are bonds
found in an amide, ester, C--C bond through Michael addition,
carbamate, disulfide bond, oxime, thiourea, hydrazone, and imine.
In some instances, the bond is a non-covalent bond. Non-limiting
examples of non-covalent bonds are those found in an interaction
such as, electrostatic interactions, hydrogen bonding, cation-.pi.,
.pi.-.pi. stacking, metal-ligand binding, and van der Waals
interactions. In some instances, the methods comprise linking two
or more flowable microgel particles together. Non-limiting examples
of linking reactions include Michael addition, amide bond coupling,
"click" chemistry (e.g. Diels-Alder cycloaddition, Huisgen
1,3-dipolar cycloaddition), reductive amination, carbamate linkage,
ester linkage, thioether linkage, disulfide bonding, hydrazone
bonding, oxime coupling, and thiourea coupling.
[0125] In some instances, methods disclosed herein comprise mixing
flowable microgel particles that contain at least one annealing
component. In general, annealing components comprise a reactive
moiety. Non-limiting examples of annealing components include
catechol (e.g., L-DOPA, dopamine), sialic acid (e.g., neuraminic
acid), boronic acid (e.g., 3-aminophenylboronic acid), a molecular
cage (e.g., cyclodextrins, cucurbiturils, calixarenes,
pillararenes, crown ethers, cavitands, cryptands, carcerands),
adamantane, biotin, and streptavidin. Additional examples of
annealing components are described herein. In some instances, the
at least one annealing component is part of a backbone polymer of a
microgel particle. In some instances, the at least one annealing
component is initially separate from the backbone polymer. In some
instances, the at least one annealing component is part of the
intracrosslinker of a microgel particle. In some instances, methods
comprise adding the at least one annealing component to the
flowable microgel particle, which may be referred to herein as
"functionalizing" the flowable microgel particle or producing a
"functionalized microgel particle." In some instances, mixing may
occur in vitro. In some instances, mixing may occur ex vivo. In
some instances, mixing may occur in vitro immediately before being
applied to a subject or medical device. In some instances, mixing
may occur ex vivo immediately before being applied to a subject or
medical device. In some instances, mixing may occur in situ. In
some instances, methods comprise applying multiple flowable
microgel particles, annealing components, and additional system
components described herein (e.g., therapeutic agents, annealing
agents, etc.) with a multi-compartment applicator (e.g.,
multi-barrel syringe) to keep these components separate until
application or immediately there before.
[0126] Methods disclosed herein may comprise annealing a first
flowable microgel particle to a second flowable microgel particle,
wherein the first flowable microgel particle and the second
flowable microgel particle are the same. This may be referred to as
"homo-annealing." An advantage to homo-annealing is that only one
type of flowable microgel particle needs to be synthesized,
simplifying the overall manufacturing process. Furthermore,
homo-annealing does not require a two-compartment container to keep
the flowable microgel particles separate until use, again
simplifying the overall manufacturing process, as well as storage
conditions. The first flowable microgel particle and the second
flowable microgel particle may be connected by an annealing agent.
In some instances, the annealing agent is a crosslinking agent. In
some instances, the annealing agent initiates annealing between the
first flowable microgel particle and the second flowable microgel
particle but does not participate in the linkage or become a part
of a resulting connection or linkage between the first flowable
microgel particle and the second flowable microgel particle. The
linkage may be covalent. The linkage may be non-covalent. A
non-limiting example of an annealing agent may be a combination of
thrombin and factor XIII. Another non-limiting example of an
annealing agent may be a combination of eosin Y and light. Yet
another non-limiting example of an annealing agent is an oxidizing
agent (e.g., silver nitrate). Additional annealing agents are
described herein. Alternatively, or additionally, the first
flowable microgel particle and the second flowable microgel
particle may be connected by a crosslinker. The crosslinker may
participate in the linkage between microgel particles and become
part of the resultant linkage. The crosslinker may be described as
a molecule that contains two or more reactive ends capable of
chemically attaching to the flowable microgel particles. In
general, the linkage is covalent.
[0127] Methods disclosed herein may comprise annealing a first
flowable microgel particle to a second flowable microgel particle,
wherein the first flowable microgel particle has a first functional
group (first annealing component) and the second flowable microgel
particle has a second functional group (second annealing
component), wherein the first functional group and the second
functional group are different. Methods may comprise mixing the
first flowable microgel particle and the second flowable microgel
particle such that the first functional group reacts with the
second functional group to form a bond. This may be referred to as
"hetero-annealing." One advantage to hetero-annealing is that an
external annealing agent or crosslinker is not required.
[0128] In some instances, the annealing component is part of the
intracrosslinking component. In some instances, the annealing
component is part of the intracrosslinker of a microgel particle.
In some instances, the second annealing component is part of the
backbone polymer of a microgel particle. In some instances, the
intracrosslinking component is part of the annealing component. In
some instances, the intracrosslinker of a microgel particle is part
of the annealing component. In some instances, the backbone polymer
of a microgel particle is part of the second annealing
component.
[0129] In some instances, methods disclosed herein comprise
synthesizing flowable microgel particles in the presence of at
least one annealing component. This may be referred to as
pre-functionalization of the flowable microgel particles. The
annealing component may be part of the intracrosslinking component.
The first annealing component may be part of the intracrosslinker
of a microgel particle. The second annealing component may be part
of the backbone polymer of a microgel particle. In some instances,
the methods comprise incorporating the first annealing component on
to a first flowable microgel particle and incorporating the second
annealing component on to a second flowable microgel particle. In
some instances, the methods comprise mixing the first annealing
component with the second annealing component, such that there is
an excess of the first annealing component (e.g., ratio of first
annealing component to second annealing component is greater than
1). In some instances, the methods comprise mixing the first
annealing component with the second annealing component, such that
there is an excess of the second annealing component (e.g., ratio
of first annealing component to second annealing component is less
than 1). The ratio of first annealing component to second annealing
component may be about 0.1, about 0.2, about 0.3, about 0.5, about
0.8, about 1, about 1.2, about 1.5, about 1.8, or about 2. In some
instances, there is a difference between an amount of the first
annealing component and the second annealing component. In some
instances, the difference is at least about 1%. In some instances,
the difference is at least about 5%. In some instances, the
difference is at least about 10%. In some instances, the difference
is at least about 20%. In some instances, the difference is at
least about 50%. In some instances, the difference is at least
about 100%. In some instances, the methods further comprise
annealing the first flowable microgel particle and the second
flowable microgel particle via the first annealing component and
second annealing component. In some instances, annealing occurs in
situ. In some instances, annealing occurs in vitro. A schematic
diagram is presented in FIG. 4 to depict an example of
pre-functionalization of flowable microgel particles. Non-limiting
examples of annealing components used for pre-functionalization
include functional groups such as vinyl sulfone, thiol, amine,
imidazole, aldehyde, ketone, hydroxyl, azide, alkyne, vinyl,
alkene, maleimide, carboxyl, N-hydroxysuccinimide (NHS) ester,
isocyanate, isothiocyanate, hydroxylamine, thione. By way of
non-limiting example, microgel particles containing an excess of
vinyl sulfone groups can covalently react with microgel particles
containing an excess of thiol groups by Michael addition to create
a microporous scaffold. Additional examples of annealing components
are described herein. In some instances, pre-functionalization is
desirable because it does not require further modification of
particles after synthesis.
[0130] In some instances, methods disclosed herein comprise
synthesizing a flowable microgel particle and subsequently
connecting an annealing component on to the microgel particle. This
may be referred to as post-functionalization of the flowable
microgel particles. A schematic diagram is presented in FIG. 5 to
depict an example of post-functionalization of flowable microgel
particles. In some instances, the methods comprise adding a first
annealing component (A in FIG. 5) to a first flowable microgel
particle and adding a second annealing component (B in FIG. 5) on
to a second flowable microgel particle. Subsequently, the first
flowable microgel particle (e.g., first functionalized
microparticle) is mixed with the second flowable microgel particle
(e.g., second functionalized microparticle) to anneal the first
flowable microgel particle and the second flowable microgel
particle via the first annealing component and second annealing
component. Non-limiting examples of connections that can be formed
between a first annealing component and a second annealing
component include a covalent bond (e.g., amide, ester, C--C bond
through Michael addition, carbamate, disulfide bond, oxime,
thiourea, hydrazone, imine), a non-covalent bond through
interaction such as (e.g., electrostatic interactions, hydrogen
bonding, cation-.pi., .pi.-.pi. stacking, metal-ligand binding, van
der Waals interactions). Another non-limiting example of an
interaction that links or connects a first annealing component and
a second annealing component is a non-covalent host-guest inclusion
complex (driven by electrostatic interactions, hydrogen bonding,
cation-.pi., .pi.-.pi. stacking, metal-ligand binding, or van der
Waals interactions). In some instances, the first flowable microgel
particle and the second flowable microgel particle are mixed
immediately before microgel application (e.g., in a subject). In
some instances, the first flowable microgel particle and the second
flowable microgel particle are mixed during microgel application
(e.g., from a multi-barrel syringe applied directly to a subject).
In some instances, annealing occurs in situ. In some instances, the
mixture anneals in situ to form a porous network. In some
instances, annealing occurs in vitro.
[0131] A non-limiting example of post-functionalization, as
described herein, is flowable microgel particles functionalized
with DOPA reacting with flowable microgel particles functionalized
with phenylboronic acid. Complexation of these flowable microgel
particles form cyclic boronate esters, thereby creating a
microporous scaffold. Another non-limiting example is flowable
microgel particles functionalized with beta-cyclodextrin
interacting with flowable microgel particles functionalized with
adamantane. Complexation of these flowable microgel particles form
a host-guest inclusion complex, thereby creating a microporous
scaffold. In some instances, post-functionalization is advantageous
because it allows more functionality options than
pre-functionalization. Post-functionalization may not be as simple
and easy as pre-functionalization as it may require an extra step
after particle synthesis. However, some annealing components cannot
be added with the pre-functionalization method. For instance, some
annealing components are unstable during particle synthesis and
cannot be used to pre-functionalize, but can be added after
particle synthesis (post-functionalization). So the
post-functionalization may allow one to functionalize flowable
microgel particles with a wider array of annealing components.
[0132] In some instances, methods disclosed herein comprise
annealing a first functionalized microgel particle to a second
functionalized microgel particle using a crosslinker. At least one
of the first functionalized microgel particle and the second
functionalized microgel particle may be a pre-functionalized
microgel particle, as described herein. At least one of the first
functionalized microgel particle and the second functionalized
microgel particle may be a post-functionalized microgel particle,
as described herein. In some instances, the first functionalized
microgel particle and the second functionalized microgel particle
are the same. In some instances, the first functionalized microgel
particle and the second functionalized microgel particle are
different. A schematic diagram is presented in FIG. 6 to depict an
example of annealing flowable microgel particles with the use of a
crosslinker. In some instances, methods disclosed herein comprise
crosslinking the first functionalized microgel particle to the
second functionalized microgel particle, wherein the crosslinking
comprises linking at least one of the first functionalized microgel
particle and the second functionalized microgel particle with a
crosslinker (B in FIG. 6). In some instances, the methods comprise
contacting at least one of the first functionalized microgel
particle and the second functionalized microgel particle with a
crosslinker after synthesizing the flowable microgel particles. In
some instances, the contacting occurs in situ. In some instances,
the contacting occurs in situ when the flowable microgel particles
are being applied to tissue of a subject. The crosslinker may be
functionalized with two or more functional groups. Non-limiting
examples of crosslinker functional groups are vinyl sulfone, thiol,
amine, imidazole, aldehyde, ketone, hydroxyl, azide, alkyne, vinyl,
alkene, maleimide, carboxyl, N-Hydroxysuccinimide (NHS) ester,
isocyanate, isothiocyanate, hydroxylamine, and thione. The
crosslinker can be homofunctional (same functional groups) or
heterofunctional (different functional groups). Examples of
crosslinking reactions using crosslinkers, include, but are not
limited to, Michael addition, amide bond coupling, "click"
chemistry (e.g. Diels-Alder cycloaddition, Huisgen 1,3-dipolar
cycloaddition), reductive amination, carbamate linkage, ester
linkage, thioether linkage, disulfide bond, hydrazone bond, oxime
coupling, and thiourea coupling.
[0133] In some instances, methods disclosed herein comprise
annealing a first functionalized microgel particle to a second
functionalized microgel particle, using a crosslinking agent. See,
e.g., FIG. 7. At least one of the first functionalized microgel
particle and the second functionalized microgel particle may be a
pre-functionalized microgel particle, as described herein. At least
one of the first functionalized microgel particle and the second
functionalized microgel particle may be a post-functionalized
microgel particle, as described herein. In some instances, the
first functionalized microgel particle and the second
functionalized microgel particle are the same. In some instances,
the first functionalized microgel particle and the second
functionalized microgel particle are different. In some instances,
the crosslinking agent is added after synthesizing the
functionalized microgel particles. In some instances, the
crosslinking agent is added during in situ application of the
microgel particles to the tissue. In some instances, the
crosslinking agent is a reducing agent. Non-limiting examples of
reducing agents are dithiothreitol, dithioerythritol,
L-glutathione, and tris (2-carboxyethyl) phosphine hydrochloride).
In some instances, the crosslinking agent is an oxidizing agent.
The oxidizing agent may be a metal complexing agent. The oxidizing
agent may be a catalyst. Non-limiting examples of oxidizing agents
are horseradish peroxidase (HRP), sodium periodate, and silver
nitrate. In some instances, the crosslinking agent induces
self-crosslinking of the annealing components present on the
flowable microgel particles. The resulting crosslinkage may
comprise at least one of a covalent bond, a coordination complex, a
hydrogen bonding, an electrostatic interaction, a cation-.pi.
interaction, a .pi.-.pi. stacking, and a van der Waals interaction.
By way of non-limiting example, DOPA-functionalized microgel
particles may be crosslinked using silver nitrate as an oxidizing
agent, wherein silver nitrate oxidizes the catechol of the DOPA
moieties into reactive quinones that can further react with another
DOPA group.
[0134] In some instances, methods comprise in situ triggered
release of a crosslinker. In some instances, methods comprise in
situ triggered release of an annealing agent. Functionalized
microgel particles, as described herein, may be annealed using a
crosslinker, annealing agent, or a crosslinking agent described
herein that is released upon a trigger during in situ application
of the flowable microgel particles to the tissue. Functionalized
microgel particles, as described herein, may be annealed using a
crosslinker, annealing agent or crosslinking agent described herein
that is released upon a trigger after in situ application of the
flowable microgel particles to the tissue. In some instances, a
crosslinker, annealing agent or crosslinking agent is entrapped in
a nanoparticle which is embedded in a microgel particle during
microparticle synthesis. In some instances, the annealing agent,
crosslinker or crosslinking agent is released by an internal
trigger. Non-limiting examples of internal triggers are tissue
mediated hydrolysis, enzyme mediated hydrolysis, hydrolysis not
mediated by tissue or enzymes, enzymolysis, redox change (e.g.
oxidative stress), pH change, and temperature change. In some
instances, the annealing agent, crosslinker or crosslinking agent
is released by an external trigger. Non-limiting examples of
external triggers are temperature, light, electromagnetic field,
and ultrasound.
[0135] Methods of producing microporous gel systems disclosed
herein may comprise incorporating a therapeutic agent into a
scaffold. Incorporating the therapeutic agent may comprise
diffusing the therapeutic agent into a collection of flowable
microgel particles. Incorporating the therapeutic agent may
comprise attaching the therapeutic agent to the flowable microgel
particles. The therapeutic agent may be attached to a flowable
microgel particle via a covalent bond. The therapeutic agent may be
attached to a flowable microgel particle via a non-covalent bond.
Incorporating the therapeutic agent may comprise photo-caging the
therapeutic agent to the microparticles.
[0136] Further provided herein are methods of producing a
microporous gel system disclosed herein, comprising encapsulating a
therapeutic agent in a nanoparticle, and mixing the therapeutic
agent and the nanoparticle with flowable microgel particles. The
nanoparticle and the therapeutic agent may be lyophilized. Methods
may comprise dissolving the nanoparticle and the therapeutic agent
(e.g., in an aqueous buffer) prior to mixing the nanoparticle and
the therapeutic agent with the flowable microgel particles.
Methods of Treatment and Uses
[0137] Provided herein are methods of treating a site of a medical
device in a tissue of a subject comprising administering to the
site: a collection of flowable microgel particles comprising a
backbone polymer and an annealing component; an annealing agent
that links the flowable microgel particles together via the
annealing component to form a stabilized scaffold of microgel
particles having interstitial spaces therein. The medical device
may be any medical device disclosed herein. The medical device may
be a surgical device, a medical implant or a biomaterial disclosed
herein.
[0138] Provided herein are methods of treating a cardiac arrhythmia
comprising administering to a chest region of a subject in need
thereof a medical device, wherein the medical device is a cardiac
implantable electronic device; a collection of flowable microgel
particles comprising a backbone polymer and an annealing component;
and an annealing agent that links the flowable microgel particles
together via the annealing component to form a stabilized scaffold
of microgel particles having interstitial spaces therein.
[0139] Provided herein are methods of treating a neurological
condition, comprising administering to a spinal region or a brain
region of a subject in need thereof, a medical device, wherein the
medical device is a neural implantable electronic device; a
collection of flowable microgel particles comprising a backbone
polymer and an annealing component; and an annealing agent that
links the flowable microgel particles together via the annealing
component to form a stabilized scaffold of microgel particles
having interstitial spaces therein.
[0140] The methods comprise administering the medical device to a
tissue of the subject. The tissue may be skin. The tissue may be
muscle. The tissue may be fascia. The tissue may be brain tissue.
The tissue may be intestinal tissue. The tissue may be adipose
tissue. The tissue may also be characterized as a tissue at a
location of the subject. The location may a brain, a skull, a
spine, an ear, an eye, a nasal sinus, a neck, a chest, an abdomen,
a stomach, a shoulder, a hip, a pelvis, a leg, an arm, a knee, an
elbow, a hand, a foot, a heart, an organ.
[0141] The methods may comprise administering the collection of
flowable microgel particles to the site before the medical device
contacts the site. The methods may comprise administering the
collection of flowable microgel particles to the site after the
medical device contacts the site. The methods may comprise
co-administering the collection of flowable microgel particles and
the medical device to the site. The methods may comprise
administering the annealing agent to the site before administering
the flowable microgel particles to the site. The methods may
comprise administering the annealing agent to the site after
administering the flowable microgel particles to the site. The
methods may comprise co-administering the collection of flowable
microgel particles and the annealing agent to the site. The
collection of flowable microgel particles and the annealing agent
may be coating the device or contained in and/or on the medical
device before the medical device is implanted.
[0142] The methods may comprise administering a therapeutic agent
disclosed herein, a backbone polymer disclosed herein, a degradable
crosslinker disclosed herein, a cell adhesive peptide, or any
combination thereof, to the site. The methods may comprise
administering the therapeutic agent, the degradable crosslinker,
the cell adhesive peptide, or any combination thereof, to the site
after, before or concurrently with the medical device, flowable
microgel particles or annealing agent. The methods may comprise
applying the therapeutic agent, the degradable crosslinker, the
cell adhesive peptide, or any combination thereof, to the medical
device.
[0143] The methods may comprise applying a stimulus to the site,
wherein the stimulus forms the stabilized scaffold. By way of
non-limiting example, the stimulus may be a chemical, an enzyme, an
agent that alters the pH of the site or the microporous gel system,
a redox stress, heat, cold, magnetic field, light, ultrasound,
electrical field, radiation, and combinations thereof. Although the
effects of the stimulus may last longer, the stimulus may be
applied for about 1 second, about 2 seconds, about 3 seconds, about
4 seconds, about 5 seconds, about 10 seconds, about 30 seconds,
about 1 minute, about 2 minutes, about 5 minutes, about 10 minutes,
about 15 minutes, about 20 minutes, about 30 minutes, about 1 hour,
about 2 hours, about 8 hours, about 12 hours, or about 1 day. The
stimulus may be applied for 1 second, 2 seconds, 3 seconds, 4
seconds, 5 seconds, 10 seconds, 30 seconds, 1 minute, 2 minutes, 5
minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 1 hour, 2
hours, 8 hours, 12 hours, or 1 day. In some cases, the stimulus is
applied for more than one day. The stimulus may be applied for
about 1 second to about 1 day. The stimulus may be applied for
about 5 seconds to about 1 day. The stimulus may be applied for
about 10 seconds to about 1 day. The stimulus may be applied for
about 30 seconds to about 1 day. The stimulus may be applied for
about 1 minute to about 1 day. The stimulus may be applied for
about 5 minutes to about 1 day. The stimulus may be applied for
about 15 minutes to about 1 day. The stimulus may be applied for
about 30 minutes to about 1 day. The stimulus may be applied for
about 1 hour to about 1 day. The stimulus may be applied for 1
second to 1 day. The stimulus may be applied for 5 seconds to 1
day. The stimulus may be applied for 10 seconds to 1 day. The
stimulus may be applied for 30 seconds to 1 day. The stimulus may
be applied for 1 minute to 1 day. The stimulus may be applied for 5
minutes to 1 day. The stimulus may be applied for 15 minutes to 1
day. The stimulus may be applied for 30 minutes to 1 day. The
stimulus may be applied for 1 hour to 1 day. The stimulus may be
applied for about 1 second to about 12 hours. The stimulus may be
applied for about 5 seconds to about 12 hours. The stimulus may be
applied for about 10 seconds to about 12 hours. The stimulus may be
applied for about 30 seconds to about 12 hours. The stimulus may be
applied for about 1 minute to about 12 hours. The stimulus may be
applied for about 5 minutes to about 12 hours. The stimulus may be
applied for about 15 minutes to about 12 hours. The stimulus may be
applied for about 30 minutes to about 12 hours. The stimulus may be
applied for about 1 hour to about 12 hours. The stimulus may be
applied for 1 second to 12 hours. The stimulus may be applied for 5
seconds to 12 hours. The stimulus may be applied for 10 seconds to
12 hours. The stimulus may be applied for 30 seconds to 12 hours.
The stimulus may be applied for 1 minute to 12 hours. The stimulus
may be applied for 5 minutes to 12 hours. The stimulus may be
applied for 15 minutes to 12 hours. The stimulus may be applied for
30 minutes to 12 hours. The stimulus may be applied for 1 hour to
12 hours. The stimulus may be applied for about 1 second to about 1
hour. The stimulus may be applied for about 5 seconds to about 1
hour. The stimulus may be applied for about 10 seconds to about 1
hour. The stimulus may be applied for about 30 seconds to about 1
hour. The stimulus may be applied for about 1 minute to about 1
hour. The stimulus may be applied for about 5 minutes to about 1
hour. The stimulus may be applied for about 15 minutes to about 1
hour. The stimulus may be applied for about 30 minutes to about 1
hour. The stimulus may be applied for about 1 hour to about 1 hour.
The stimulus may be applied for 1 second to 1 hour. The stimulus
may be applied for 5 seconds to 1 hour. The stimulus may be applied
for 10 seconds to 1 hour. The stimulus may be applied for 30
seconds to 1 hour. The stimulus may be applied for 1 minute to 1
hour. The stimulus may be applied for 5 minutes to 1 hour. The
stimulus may be applied for 15 minutes to 1 hour. The stimulus may
be applied for 30 minutes to 1 hour.
[0144] Methods of treatment and uses described herein may result in
a tissue remodeling or cellular effect in the subject. In some
instances, use of microporous gel system to microporous scaffold
disclosed herein results in eliminating inflammation at a wound or
surgical site. Elimination of inflammation may be evidenced by an
absence of MNGC at the wound or surgical site. Elimination of
inflammation may be evidenced by a similar number of MNGC at the
wound or surgical site as compared to a non-wound site (e.g.,
healthy, non-damaged tissue). Elimination of inflammation may be
evidenced by a reduction or absence of neutrophils or macrophages
at the wound or surgical site. Elimination of inflammation may be
evidenced by a similar number of neutrophils or macrophages at the
wound or surgical site as compared to a non-wound site (e.g.,
healthy, non-damaged tissue). In some instances, tissue of the
subject integrates with the microporous scaffold. In some
instances, at least a portion of the microporous scaffold degrades
in situ. In some instances, at least about 10% of the microporous
scaffold degrades in situ. In some instances, at least about 30% of
the microporous scaffold degrades in situ. In some instances, at
least about 60% of the microporous scaffold degrades. In some
instances, at least about 90% of the microporous scaffold degrades
in situ. In some instances, the microporous scaffold completely
degrades in situ. In some instances, at least one of a wound site
and a microporous scaffold is vascularized after administration of
a gel disclosed herein. Vascularization may result in the presence
of large vessels with intimal walls. Large vessels may be vessels,
wherein at least a portion of the blood vessel has a diameter
greater than about 10 .mu.m. In some instances, the wound site
develops a web-like dermal tissue, which indicates non-fibrous
tissue formation. In some instances, the wound site does not
develop fibrous tissue.
[0145] The extent of any tissue remodeling or cellular effect
described herein, (e.g., elimination of inflammation, integration
of tissue, degradation of the microporous scaffold, and
vascularization of the microporous scaffold), may occur within a
time range from the time the gel was administered. The time range
may depend upon the tissue to which the microporous scaffold is
administered. The time range may be about 5 days to about 10 days.
The time range maybe about 10 days to about 20 days. The time range
may be about 20 days to about 30 days. The time range may be about
30 days to about 40 days. The time range may be about 40 days to
about 50 days. The time range may be about 50 days to about 100
days.
[0146] Methods of administering a microporous gel system and device
to a subject may result in microgel particle--substrate annealing,
wherein a bond forms between a flowable microgel particle and a
substrate (medical device or tissue of the subject). The bond can
be covalent. The bond can be non-covalent. In some instances, the
bond forms between a flowable microgel particle and a device
coating. In some instances, the medical device is pre-coated with a
functional group that is capable of binding to at least one
flowable microgel particle of a collection of flowable microgel
particles. In some instances, the substrate binds to a first layer
of flowable microgel particles, the latter of which binds to a
second layer of microgel particles. The first layer of flowable
microgel particles may comprise the same type of flowable microgel
particles as the second layer of flowable microgel particles. The
first layer of flowable microgel particles may comprise a different
type of flowable microgel particles as the second layer of flowable
microgel particles. In some instances, microgel particle-substrate
annealing occurs simultaneously with particle-particle annealing.
In some instances, microgel particle-substrate annealing occurs
before particle-particle annealing. In some instances, microgel
particle-substrate annealing occurs after particle-particle
annealing.
Diseases and Conditions
[0147] Provided herein are methods and systems for the treatment of
a condition or disease in a subject, comprising administering any
combination of microporous gel systems, medical devices and
therapeutic agents disclosed herein. The condition or disease may
be an acute condition or disease. By way of non-limiting example,
the acute condition or disease may be a dermal wound, a deep
surgical wound, an amputation, or a stroke. The condition or
disease may be a chronic condition or disease. By way of
non-limiting example, the chronic condition or disease may be a
non-healing wound, heart arrhythmia, epilepsy, or osteoarthritis.
The condition or disease may be a degenerative disease. By way of
non-limiting example, the degenerative disease may be a
neurodegenerative disease (e.g., Alzheimer's, Parkinson's or
multiple sclerosis) or a cancer. The condition or disease may be a
metabolic condition or disease (e.g., diabetes). By way of
non-limiting example, the metabolic condition or disease may be
diabetes or obesity. The condition or disease may be an orthopedic
disorder (e.g., musculoskeletal trauma, arthritis, fractures,
infections, osteoporosis, ligament injuries).
[0148] Provided herein are methods and systems for the treatment of
a cardiovascular condition, a cardiovascular disease, a heart
condition or a heart disease disclosed herein. A cardiovascular
condition or cardiovascular disease is a condition or disease
wherein vasculature of the subject is affected. The heart condition
or heart disease may be a condition or disease that affects the
function of the heart, such as the electrical function, pumping
function or valve function, without affecting the health of the
vasculature of the heart or cardiovascular system. The methods and
systems disclosed herein provide for treatment of both heart and
cardiovascular diseases and conditions, and combinations thereof.
However, these terms may be used interchangeably herein, unless
otherwise specified. Heart conditions include, but are not limited
to atrial fibrillation, ventricular fibrillation, chronic heart
failure, coronary artery disease, myocarditis, peripheral arterial
occlusive disease, cardiomyopathy, pericarditis, myocarditis,
endocarditis, a congenital heart defect, atherosclerosis, and
combinations thereof. Heart conditions include cardiac arrhythmias.
The cardiac arrhythmia may be acute. The cardiac arrhythmia may be
chronic. The cardiac arrhythmia may be environmentally induced. The
cardiac arrhythmia may be exercise induced. The cardiac arrhythmia
may be caused by a genetic mutation. The cardiac arrhythmia may be
caused by an infection.
[0149] Provided herein are methods and systems for the treatment of
a neurological disease or a neurological condition disclosed
herein. The neurological condition may be chronic. The neurological
condition may be acute. The neurological condition may be due to an
injury. By way of non-limiting example, the neurological disease or
neurological condition may be Parkinson's Disease, Alzheimer's
Disease, tremor, dystonia, chronic pain, major depression,
obsessive compulsive disorder, schizophrenia, epilepsy, addictions,
stroke, multiple sclerosis, traumatic brain injury, spinal cord
injury, encephalitis, cerebral ischemia, or an intestinal
condition. The neurological condition may be speech defect, hearing
defect, paralysis, or partial-paralysis.
[0150] Various embodiments contemplated herein may include, but
need not be limited to, one or more of the following, and
combinations thereof:
[0151] Embodiment 1: A system comprising: a collection of flowable
microgel particles, wherein the flowable microgel particles
comprise a backbone polymer; at least one annealing component; and
a medical device, wherein the flowable microgel particles are
capable of being linked together via the at least one annealing
component to form a stabilized scaffold having interstitial spaces
therein.
[0152] Embodiment 2: A system comprising: a collection of flowable
microgel particles, wherein the flowable microgel particles
comprise a backbone polymer; at least one annealing component; and
a medical device, wherein the flowable microgel particles are
linked together via the at least one annealing component to form a
stabilized scaffold having interstitial spaces therein.
[0153] Embodiment 3: The system of embodiment 1 or 2, comprising an
intercrosslinker that links the flowable microgel particles
together via the at least one annealing component.
[0154] Embodiment 4: The system of embodiment 1 or 2, comprising an
annealing agent that links the flowable microgel particles together
via the at least one annealing component.
[0155] Embodiment 5: The system of embodiment 4, wherein the
annealing agent is an intercrosslinking agent.
[0156] Embodiment 6: The system of embodiment 1 or 2, comprising a
first annealing component and a second annealing component.
[0157] Embodiment 7: The system of embodiment 6, wherein the first
annealing component and the second annealing component are the
same.
[0158] Embodiment 8: The system of embodiment 6, wherein the first
annealing component and the second annealing component are
different.
[0159] Embodiment 9: The system of embodiment 1 or 2, wherein the
at least one annealing component is a substrate for an enzyme of a
mammalian subject.
[0160] Embodiment 10: The system of embodiment 1 or 2, a first
annealing component and a second annealing component are linked
together when exposed to a condition in a mammalian subject.
[0161] Embodiment 11: The system of any one of embodiments 1-10,
wherein the medical device is a medical implant.
[0162] Embodiment 12: The system of any one of embodiments 1-10,
wherein the medical device comprises an electrode.
[0163] Embodiment 13: The system of any one of embodiments 1-10,
wherein the medical device comprises an electrical component.
[0164] Embodiment 14: The system of any one of embodiments 1-10,
wherein the medical device comprises a coating, wherein the coating
comprises at least one of the annealing component and an annealing
agent.
[0165] Embodiment 15: The system embodiment 11, wherein the medical
implant is a cardiac implantable electronic device.
[0166] Embodiment 16: The system of embodiment 15, wherein the
cardiac implantable electronic device is a pacemaker.
[0167] Embodiment 17: The system of embodiment 15, wherein the
cardiac implantable electronic device is a defibrillator.
[0168] Embodiment 18: The system of embodiment 11, wherein the
medical implant is a neural implantable electronic device.
[0169] Embodiment 19: The system of embodiment 1 or 2, wherein the
stabilized scaffold maintains placement of the medical device in a
surgical void of a subject.
[0170] Embodiment 20: The system of embodiment 2, wherein the
stabilized scaffold has a custom form determined by the medical
device and the surgical void.
[0171] Embodiment 21: The system of embodiment 2, wherein the
stabilized scaffold comprises non-covalent bonds between the
flowable microgel particles.
[0172] Embodiment 22: The system of embodiment 2, wherein the
stabilized scaffold comprises covalent bonds between the flowable
microgel particles.
[0173] Embodiment 23: The system of any preceding embodiment,
comprising a therapeutic agent.
[0174] Embodiment 24: The system of embodiment 23, wherein the
therapeutic agent is an anti-inflammatory agent, an antimicrobial
agent, or an analgesic.
[0175] Embodiment 25: The system of embodiment 23, wherein the
therapeutic agent is incorporated in the stabilized scaffold.
[0176] Embodiment 26: The system of embodiment 2, comprising a
therapeutic agent, wherein the stabilized scaffold releases the
therapeutic agent from the stabilized scaffold when the stabilized
scaffold is present in a mammalian subject.
[0177] Embodiment 27: The system of embodiment 26, wherein the
stabilized scaffold releases at least a portion of the therapeutic
agent from the stabilized scaffold in less than one day from its
initial presence in the mammalian subject.
[0178] Embodiment 28: The system of embodiment 26, wherein the
stabilized scaffold releases the therapeutic agent from the
stabilized scaffold over a period of less than 1 day to 100
days.
[0179] Embodiment 29: The system of embodiment 25, comprising a
therapeutic agent releasing agent that releases the therapeutic
agent from the stabilized scaffold.
[0180] Embodiment 30: The system of embodiment 25, wherein the
therapeutic agent is released by tissue mediated hydrolysis.
[0181] Embodiment 31: The system of embodiment 25, wherein the
therapeutic agent is released by passive hydrolysis.
[0182] Embodiment 32: The system of embodiment 25, wherein the
therapeutic agent is released by a temperature change.
[0183] Embodiment 33: The system of any preceding embodiment,
comprising a nanoparticle.
[0184] Embodiment 34: The system of embodiment 33, wherein the
therapeutic agent is connected to or contained within the
nanoparticle.
[0185] Embodiment 35: The system of embodiment 33, wherein the
nanoparticle is a mesoporous silica nanoparticle.
[0186] Embodiment 36: The system of embodiment 33, wherein the
nanoparticle comprises poly(lactic-co-glycolic acid).
[0187] Embodiment 37: The system of embodiment 33, wherein the
nanoparticle comprises chitosan.
[0188] Embodiment 38: The system of embodiment 33, wherein the
nanoparticle comprises hyaluronic acid.
[0189] Embodiment 39: The system of embodiment 33, wherein the
nanoparticle comprises a poly(anhydride), a poly(amide), a
poly(ortho ester), a polycaprolactone, or a combination
thereof.
[0190] Embodiment 40: The system of embodiment 33, wherein the
nanoparticle comprises a polymer with a lower critical solution
temperature (LCST).
[0191] Embodiment 41: The system of embodiment 40, wherein the
polymer is poly(N-isopropylacrylamide) or a co-polymer thereof.
[0192] Embodiment 42: The system of embodiment 33, wherein the
nanoparticle comprises a polymer with an upper critical solution
temperature (UCST).
[0193] Embodiment 43: The system of embodiment 42, wherein the
polymer is poly(hydroxyethylmethacrylate), polyethylene oxide, or
poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide).
[0194] Embodiment 44: The system of embodiment 33, wherein the
nanoparticle comprises a self-immolating polymer.
[0195] Embodiment 45: The system of embodiment 44, wherein the
polymer is poly(p-aminobenzyl oxycarbonyl).
[0196] Embodiment 46: The system of embodiment 44, wherein the
polymer is capped with a cage that can be released upon a
stimulus.
[0197] Embodiment 47: The system of embodiment 33, wherein the
system comprises a core-shell nanoparticle system.
[0198] Embodiment 48: The system of embodiment 47, wherein a first
portion of the flowable microgel particles comprises the core-shell
nanoparticle system and wherein the second portion of flowable
microgel particles comprises a shell-dissolving agent, wherein the
shell-dissolving agent is capable of releasing the therapeutic
agent when the first portion of the flowable microgel particles is
in contact with the second portion of flowable microgel
particles.
[0199] Embodiment 49: The system of embodiment 48, comprising a
first container containing the first portion and a second container
containing the second portion.
[0200] Embodiment 50: The system of embodiment 3, wherein the
intercrosslinker is degradable in a mammalian subject.
[0201] Embodiment 51: The system of any preceding embodiment,
comprising a cell adhesive peptide.
[0202] Embodiment 52: The system of embodiment 4, wherein the
annealing agent comprises a light source.
[0203] Embodiment 53: The system of embodiment 1, wherein the
collection of flowable microgel particles and annealing agent are
stored or administered from a single container.
[0204] Embodiment 54: The system of embodiment 1, wherein at least
two of the flowable microgel particles are present in separate
containers.
[0205] Embodiment 55: The system of embodiment 8, wherein the first
annealing component and the second annealing component are present
in separate containers.
[0206] Embodiment 56: The system of embodiment 1, comprising an
application device, wherein the application device is configured to
apply the flowable microgel particles and the at least one
annealing component to a tissue of a subject.
[0207] Embodiment 57: The system of embodiment 56, wherein the
application device comprises a syringe, a spatula, a squeezable
tube or a cannula.
[0208] Embodiment 58: The system of embodiment 56, wherein the
application device comprises a multi-barrel syringe, and wherein at
least a first portion of the flowable microgel particles or a first
portion of the annealing component is in a first barrel, and a
second portion of the flowable microgel particles or a second
portion of the annealing component is in a second barrel.
[0209] Embodiment 59: The system of embodiment 1, wherein the
microporous gel system has a shelf life of at least about one year
at room temperature.
[0210] Embodiment 60: A system according to any one of embodiments
1-59 for use in the treatment of a wound or surgical site.
[0211] Embodiment 61: A method of treating a site of a medical
device in a tissue of a subject comprising administering to the
site: a collection of flowable microgel particles, wherein the
flowable microgel particles comprise a backbone polymer; at least
one annealing component; and a medical device, wherein the flowable
microgel particles are capable of being linked together via the at
least one annealing component to form a stabilized scaffold having
interstitial spaces therein.
[0212] Embodiment 62: A method of reducing or preventing fibrosis
at a site of a medical device in a tissue of a subject comprising
administering to the site: a collection of flowable microgel
particles, wherein the flowable microgel particles comprise a
backbone polymer; at least one annealing component; and a medical
device, wherein the flowable microgel particles are capable of
being linked together via the at least one annealing component to
form a stabilized scaffold having interstitial spaces therein.
[0213] Embodiment 63: A method of reducing or preventing
inflammation at a site of a medical device in a tissue of a subject
comprising administering to the site: a collection of flowable
microgel particles, wherein the flowable microgel particles
comprise a backbone polymer; at least one annealing component; and
a medical device, wherein the flowable microgel particles are
capable of being linked together via the at least one annealing
component to form a stabilized scaffold having interstitial spaces
therein.
[0214] Embodiment 64: The method of any one of embodiments 61 to
63, wherein the medical device is a surgical device.
[0215] Embodiment 65: The method of any one of embodiments 61 to
63, wherein the medical device is a medical implant.
[0216] Embodiment 66: The method of any one of embodiments 61 to
63, comprising administering at least one of the annealing
component and the flowable microgel particles to the site before
administering the medical device to the site.
[0217] Embodiment 67: The method of any one of embodiments 61 to
63, comprising administering at least one of the annealing
component and the flowable microgel particles to the site after
administering the medical device to the site.
[0218] Embodiment 68: The method of any one of embodiments 61 to
63, comprising co-administering at least one of the annealing
component and the flowable microgel particles, and the medical
device to the site.
[0219] Embodiment 69: The method of any one of embodiments 61 to
63, comprising administering at least one of the annealing
component and the flowable microgel particles with a syringe,
cannula, squeezable tube or spatula.
[0220] Embodiment 70: The method any one of embodiments 61 to 69,
comprising administering an annealing agent.
[0221] Embodiment 71: The methods of embodiment 70, comprising
administering the annealing agent before administering at least one
of the annealing component and the flowable microgel particles.
[0222] Embodiment 72: The method of embodiment 70, comprising
administering the annealing agent after administering at least one
of the annealing component and the flowable microgel particles.
[0223] Embodiment 73: The method of embodiment 70, comprising
co-administering the annealing agent and at least one of the
annealing component and the flowable microgel particles.
[0224] Embodiment 74: The method of any one of embodiments 61-73,
comprising administering a therapeutic agent to the site.
[0225] Embodiment 75: The method of embodiment 74, comprising
administering a therapeutic agent releasing agent to the site,
wherein the therapeutic agent releasing agent releases the
therapeutic agent from the stabilized scaffold to the site or
tissue.
[0226] Embodiment 76: The method of embodiment 74, comprising
incorporating the therapeutic agent into the stabilized
scaffold.
[0227] Embodiment 77: The method of embodiment 74, wherein the
stabilized scaffold comprises a core-shell nanoparticle system
wherein the therapeutic agent is connected to or contained within
the core-shell nanoparticle system, comprising applying an external
stimulus to the stabilized scaffold to release the therapeutic
agent to the site or tissue.
[0228] Embodiment 78: The method of embodiment 77, wherein the
external stimulus selected from light, electromagnetic radiation,
or temperature change.
[0229] Embodiment 79: The method of embodiment 61, comprising
changing a condition of the site after formation of the stabilized
scaffold.
[0230] Embodiment 80: The method of embodiment 61, comprising
changing a condition of the site before formation of the stabilized
scaffold.
[0231] Embodiment 81: The method of embodiment 79 or 80, wherein
changing the condition comprises at least one of changing
temperature of the site, changing pH of the site, changing
chemistry of the site, applying an exogenous enzyme, activating an
endogenous enzyme, applying a magnetic field, applying a form of
radiation, applying light, and applying ultrasound.
[0232] Embodiment 82: A method of treating a heart condition
comprising administering to a subject in need thereof: a collection
of flowable microgel particles, wherein the flowable microgel
particles comprise a backbone polymer; at least one annealing
component; and a cardiac implantable electronic device, wherein the
flowable microgel particles are capable of being linked together
via the at least one annealing component to form a stabilized
scaffold having interstitial spaces therein.
[0233] Embodiment 83: The method of embodiment 82, wherein the
heart condition is a heart arrhythmia.
[0234] Embodiment 84: The method of embodiment 82, wherein the
heart condition is a sustained ventricular tachycardia.
[0235] Embodiment 85: The method of embodiment 82, wherein the
heart condition is a ventricular fibrillation.
[0236] Embodiment 86: A method of treating a neurological condition
comprising administering to a subject in need thereof: a collection
of flowable microgel particles, wherein the flowable microgel
particles comprise a backbone polymer; at least one annealing
component; and a neural implantable electronic device, wherein the
flowable microgel particles are capable of being linked together
via the at least one annealing component to form a stabilized
scaffold having interstitial spaces therein.
[0237] Embodiment 87: A method of producing a microporous scaffold,
comprising: synthesizing a first portion of flowable microgel
particle in the presence of a first annealing component and a
second annealing component, wherein there is more of the first
annealing component than the second annealing component to produce
a first functionalized microgel particle; synthesizing a second
portion of flowable microgel particle in the presence of the first
annealing component and the second annealing component, wherein
there is more of the second annealing component than the first
annealing component to produce a second functionalized microgel
particle; combining the first functionalized microgel particle and
the second functionalized microgel particle such that the first
functionalized microgel particle and the second functionalized
microgel particle connect, thereby producing a microporous scaffold
of microgel particles having interstitial spaces therebetween.
[0238] Embodiment 88: The method of embodiment 87, wherein there is
at least 1% more of the first annealing component than the second
annealing component in step (a).
[0239] Embodiment 89: The method of embodiment 87, wherein there is
at least 1% more of the second annealing component than the first
annealing component in step (b).
[0240] Embodiment 90: The method of embodiment 87, wherein at least
one of the first annealing component and the second annealing
component comprise a functional group selected from a vinyl
sulfone, thiol, amine, imidazole, aldehyde, ketone, hydroxyl,
azide, alkyne, vinyl, alkene, maleimide, carboxyl,
N-hydroxysuccinimide (NHS) ester, isocyanate, isothiocyanate,
hydroxylamine, and thione.
[0241] Embodiment 91: The method of embodiment 87, wherein the
first functionalized microgel particle and the second
functionalized microgel particle connect through a reaction
selected from Michael addition, amide bond coupling, Diels-Alder
cycloaddition, Huisgen 1,3-dipolar cycloaddition, reductive
amination, carbamate linkage, ester linkage, thioether linkage,
disulfide bonding, hydrazone bonding, oxime coupling, and thiourea
coupling.
[0242] Embodiment 92: The method of embodiment 87, wherein the
first functionalized microgel particle and the second
functionalized microgel particle connect to produce a covalent
bond.
[0243] Embodiment 93: The method of embodiment 87, wherein the
first functionalized microgel particle and the second
functionalized microgel particle connect to produce a non-covalent
bond.
[0244] Embodiment 94: The method of embodiment 87, wherein the
first functionalized microgel particle and the second
functionalized microgel particle connect to produce a connection
selected from a C--C bond, an amide bond, an amine bond, a
carbamate linkage, an ester linkage, a thioether linkage, a
disulfide bond, a hydrazine bond, an oxime coupling and a thiourea
coupling.
[0245] Embodiment 95: The method of embodiment 87, wherein at least
one step of the method is performed in situ.
[0246] Embodiment 96: A method of producing a microporous scaffold,
comprising: synthesizing flowable microgel particles; contacting a
first portion of the flowable microgel particles with a first
annealing component to produce a first functionalized microgel
particle; contacting a second portion of the flowable microgel
particles with a second annealing component to produce a second
functionalized microgel particle; combining the first
functionalized microgel particle and the second functionalized
microgel particle such that the first functionalized microgel
particle and the second functionalized microgel particle connect,
thereby producing a microporous scaffold of microgel particles
having interstitial spaces therebetween.
[0247] Embodiment 97: The method of embodiment 96, wherein at least
one of the first annealing component and the second annealing
component comprise a reactive moiety selected from a catechol, a
sialic acid, a boronic acid, a molecular cage, adamantane, biotin,
and streptavidin.
[0248] Embodiment 98: The method of embodiment 97, wherein the
molecular cage is selected from a cyclodextrin, a cucurbituril, a
calixarene, a pillararene, a crown ether, a cavitand, a cryptand,
and a carcerand.
[0249] Embodiment 99: The method of embodiment 96, wherein the
first functionalized microgel particle and the second
functionalized microgel particle connect through a covalent
bond.
[0250] Embodiment 100: The method of embodiment 99, wherein the
covalent bond is selected from an amide, ester, C--C bond,
carbamate, disulfide bond, oxime, thiourea, hydrazone, and
imine.
[0251] Embodiment 101: The method of embodiment 96, wherein the
first functionalized microgel particle and the second
functionalized microgel particle connect through a non-covalent
bond.
[0252] Embodiment 102: The method of embodiment 101, wherein the
non-covalent bond is selected from an electrostatic interaction, a
hydrogen bond, a cation-.pi., .pi.-.pi. stack, a metal-ligand bond,
a van der Waals interaction, and a non-covalent host-guest
inclusion complex.
[0253] Embodiment 103: The method of embodiment 96, wherein at
least one step of the method is performed in situ.
[0254] Embodiment 104: The method of any one of embodiments 87-103,
comprising contacting the first functionalized microgel particle
and the second functionalized microgel particle with an
intercrosslinker in order to connect the first functionalized
microgel particle and the second functionalized microgel
particle.
[0255] Embodiment 105: The method of embodiment 104, wherein the
contacting occurs in situ.
[0256] Embodiment 106: The method of embodiment 104, wherein the
contacting occurs after synthesizing the flowable microgel
particles.
[0257] Embodiment 107: The method of embodiment 104, wherein the
intercrosslinker comprises at least one functional group.
[0258] Embodiment 108: The method of embodiment 104, wherein the
intercrosslinker comprises at least two functional groups.
[0259] Embodiment 109: The method of embodiment 107 or 108, wherein
at least one functional group is selected from a vinyl sulfone, a
thiol, an amine, an imidazole, an aldehyde, a ketone, a hydroxyl,
an azide, an alkyne, a vinyl, an alkene, a maleimide, a carboxyl, a
N-Hydroxysuccinimide (NHS) ester, an isocyanate, an isothiocyanate,
ahydroxylamine, and a thione.
[0260] Embodiment 110: The method of embodiment 104, wherein the
connecting the first functionalized microgel particle and the
second functionalized microgel particle comprises a reaction
selected from Michael addition, amide bond coupling, Diels-Alder
cycloaddition, Huisgen 1,3-dipolar cycloaddition, reductive
amination, carbamate linkage, ester linkage, thioether linkage,
disulfide bond, hydrazone bond, oxime coupling, and thiourea
coupling.
[0261] Embodiment 111: The method of any one of embodiments 87-110,
comprising contacting the first functionalized microgel particle
and the second functionalized microgel particle with an
intercrosslinking agent.
[0262] Embodiment 112: The method of embodiment 111, wherein the
intercrosslinking agent comprises a reducing agent.
[0263] Embodiment 113: The method of embodiment 112, wherein the
reducing agent comprises at least one of dithiothreitol,
dithioerythritol, L-glutathione, and tris (2-carboxyethyl)
phosphine hydrochloride.
[0264] Embodiment 114: The method of embodiment 110, wherein the
intercrosslinking agent comprises an oxidizing agent.
[0265] Embodiment 115: The method of embodiment 114, wherein the
oxidizing agent comprises at least one of horseradish peroxidase
(HRP), sodium periodate, and silver nitrate.
[0266] Embodiment 116: The method of embodiment 111, wherein the
intercrosslinking agent induces self-crosslinking of functional
groups present on at least one of the annealing component flowable
microgel particles or annealing components to produce a
crosslinkage.
[0267] Embodiment 117: The method of embodiment 116, wherein the
crosslinkage comprises at least one of a covalent bond, a
coordination complex, a hydrogen bond, an electrostatic
interaction, a cation-.pi. interaction, a .pi.-.pi. stack, and a
van der Waals interaction.
[0268] Embodiment 118: The method of embodiment 111, comprising
contacting the first functionalized microgel particle and the
second functionalized microgel particle with the intercrosslinking
agent in situ.
[0269] Embodiment 119: The method of any one of embodiments
104-118, comprising applying an external stimulus to the
microporous scaffold to release the intercrosslinker.
[0270] Embodiment 120: The method of embodiment 119, wherein
applying an external stimulus to the microporous scaffold occurs
indirectly by applying the external stimulus to tissue around the
microporous scaffold.
[0271] Embodiment 121: The method of embodiment 119, wherein the
external stimulus is selected from light, an electromagnetic field,
ultrasound, heat, cooling, and a combination thereof.
[0272] Embodiment 122: The method of anyone of embodiments 87-121,
comprising incorporating a therapeutic agent into the stabilized
scaffold.
[0273] Embodiment 123: The method of embodiment 122, wherein
incorporating comprises at least one of diffusing the therapeutic
agent into the collection of flowable microgel particles;
covalently linking the therapeutic agent to the flowable microgel
particles; and photo-caging the therapeutic agent to the microgel
particles.
[0274] Embodiment 124: The method of embodiment 122, wherein
incorporating comprises encapsulating the therapeutic agent in a
nanoparticle, and mixing the therapeutic agent and the nanoparticle
with the flowable microgel particles.
[0275] Embodiment 125: The method of embodiment 124, wherein the
nanoparticle and the therapeutic agent are lyophilized, comprising
dissolving the nanoparticle and the therapeutic agent in aqueous
buffer prior to mixing the nanoparticle and the therapeutic agent
with the flowable microgel particles.
[0276] Embodiment 126: The method of embodiment 112, wherein
transferring and removing occur substantially simultaneously.
[0277] Embodiment 127: A method of purifying flowable microgel
particles comprising: obtaining a membrane filtration system;
transferring flowable microgel particles from a first solvent to a
second solvent, wherein the second solvent is immiscible with the
first solvent, by controlled addition of a third solvent to the
first solvent such that a single miscible phase containing the
flowable microgel particles is maintained; and removing an impurity
from the flowable microgel particles.
[0278] Embodiment 128: The method of embodiment 127, wherein
transferring and removing occur substantially simultaneously.
[0279] Embodiment 129: The method of embodiment 127, wherein the
membrane filtration system requires a single miscible phase for
function.
[0280] Embodiment 130: The method of embodiment 127, wherein the
membrane filtration system is selected from tangential flow
filtration (TFF), ultrafiltration-diafiltration (UFDF),
microfiltration-diafiltration (MFDF), or hollow-fiber-diafiltration
(HFDF).
[0281] Embodiment 131: The method of embodiment 127, wherein the
first solvent is a non-polar oil and the second solvent is
water.
[0282] Embodiment 132: The method of embodiment 127, wherein the
third solvent is an alcohol solution.
[0283] Embodiment 133: The method of embodiment 127, wherein the
impurity is a surfactant.
[0284] Embodiment 134: A method of concentrating flowable microgel
particles in a solution or suspension comprising: pumping the
flowable microgel particles through a membrane filtration system
while a continuous phase volume is removed; continually
concentrating the flowable microgel particles at a controlled
membrane flux; and maintaining a wall shear stress inside the
membrane filtration system.
[0285] Embodiment 135: The method of embodiment 134, wherein the
membrane filtration system is selected from tangential flow
filtration (TFF), ultrafiltration-diafiltration (UFDF),
microfiltration-diafiltration (MFDF), or hollow-fiber-diafiltration
(HFDF).
[0286] Embodiment 136: The method of embodiment 134, wherein the
membrane flux is controlled between 100 and 1000 L/m2h.
[0287] Embodiment 137: The method of embodiment 134, wherein the
wall shear stress is maintained between 100 s.sup.-1 and 10,000
s.sup.-1.
EXAMPLES
[0288] The examples and embodiments described herein are for
illustrative purposes only and are not intended to limit the scope
of the claims provided herein. Various modifications or changes
suggested to persons skilled in the art are to be included within
the spirit and purview of this application and scope of the
appended claims.
Example 1
Synthesis of Flowable Microgel Particles
[0289] Flowable microgel particles were synthesized by a
water-in-oil emulsion and purified by tangential flow filtration
(TFF) (see FIG. 8). The manufacturing process was performed
aseptically. The reaction vessel, glassware, connectors, fittings,
filters, tubing and TFF system were depyrogenated and then
sterilized using a sterilization technique (e.g., gamma radiation
or moist heat (autoclave)). All the prepared solutions were
filtered prior to the addition to the reaction vessel. Buffers and
solvents used for purification were added to a sterile bag through
a 0.2 .mu.m filter.
[0290] Oil phase preparation: 7 L of light mineral oil (LMO) with
70 mL of span80 (1%v/v) was prepared. 5.7 L of the LMO+span80
mixture was added to a 6-L bioreactor vessel through a 0.2 .mu.m
filter and stirred with a 70-mm impeller rod at 800 rpm.
[0291] PEG intracrosslinker solution preparation: an aqueous
solution containing 10% w/v 4-arm poly(ethylene glycol) vinyl
sulfone (PEG-VS) (20 kDa), 500 .mu.M K-peptide (Ac-FKGGERCG-NH2),
500 .mu.M Q-peptide (Ac-NQEQVSPLGGERCG-NH2) and 1 mM RGD
(Ac-RGDSPGERCG-NH2) was prepared in 300 mM triethanolamine (pH
7.75). The PEG solution was filtered using a 0.22 .mu.m Stericup
PES filter.
[0292] Peptide Intracrosslinker solution preparation: an 8 mM
di-cysteine MMP-sensitive peptide (Ac-GCRDGPQGIWGQDRCG-NH2) aqueous
solution was prepared. The crosslinker solution was filtered using
a 0.22 .mu.m Stericup PES filter.
[0293] Water-in-oil (w/o) emulsion: 150 mL of the PEG solution was
mixed 1:1 to 150 mL of the crosslinker solution. Immediately after
mixing, the aqueous mixture (300 mL, 5%v/v w/o) was injected using
a peristaltic pump (135 mL/min) to the stirring oil phase. After 2
h of stirring, the particles were allowed to settle down overnight
and accumulated at the bottom of the reaction vessel. Because the
particles are denser that LMO, they settled and accumulated at the
bottom of the 6-L reaction vessel.
[0294] Approximately 80% (-4.8 L) of the oil phase was removed
using a peristaltic pump and dip tubes of the vessel.
[0295] The particles were redispersed in 4.8 L of 95%
isopropanol/5% water (referred to as 95% IPA solution) and stirred
for at least 5 min at 450 rpm.
[0296] The particles were harvested in a 50 L sterile bag: at the
same rate liquid is removed from the 6-L vessel, 95% IPA solution
was added to the vessel to keep the volume constant (6 L) during
particle harvest until 50 L of 95% IPA solution has been
transferred through the 6-L vessel into the harvest bag.
Example 2
Purification of Flowable Microgel Particles
[0297] Tangential flow filtration was used to purify and
concentrate flowable microgel particles produced as described in
Example 1.
[0298] The membrane used in this system was a Spectrum hollow fiber
mPES membrane (P/N N02-E65U-07-N, pore rating=0.65 .mu.m, lumen
ID=0.75 mm, surface area 1,800 cm.sup.2).
[0299] The TFF system was gamma irradiated for sterilization.
[0300] The TFF system was plumbed to a lab stand with a Master Flex
pump installed onto the retentate loop (see FIG. 8). Spectrum Labs
luer lock pressure transducers were placed on the filter inlet,
outlet, and permeate in order to monitor the flows. The 50-L bag
containing the harvested microparticles dispersed in 95% IPA
solution was connected to the TFF inlet manifold.
[0301] The particles were transferred from the bag into the TFF
reservoir (V=3.5 L) and circulated through the retentate loop at 5
L/min (permeate valve close).
[0302] The particles were slowly concentrated (permeate valve
open): the volume in the reservoir (3.5 L) was kept constant by
pumping in microparticles as volume is removed through the
permeate. The permeate flow was adjusted to target a filtrate flux
rate between 200 and 300 LMH.
[0303] A gradient of solvents (from 95% isopropanol to 100% water
and finally buffer) was used to purify the particles. All the
solvents and buffers were stored in a sterile bag. A constant
volume diafiltration was performed with 20 L of each of the
following solutions: 95% IPA solution, 50% IPA solution, 100% pure
water, and final formulation buffer (10 mM phosphate buffer+100 mM
NaCl+5 .mu.M Eosin Y, pH 7.4). The permeate flow was adjusted to
target a filtrate flux rate between 200 and 300 LMH.
[0304] The particles were concentrated by TFF until the material
reached the targeted concentration.
[0305] The particles were harvested in sterile bags and eventually
concentrated further by centrifugation if necessary.
Example 3
Wound Healing in Pigs Using Microporous Gel Systems
[0306] Wound beds in pigs were completely filled by a microporous
gel that stabilized into a microporous scaffold. The microporous
gel was produced as described in Example 1. Briefly, the
microporous gel was made of the backbone polymer
4-ARM-PEG-VS+MMP-degradable peptide+RGD+K+Q peptides in final
formulation buffer (PBS+5 uM Eosin Y). The gel was annealed by
light with eosin Y as an annealing agent. As controls, pigs with
similar defects were treated with an Oasis.RTM. SIS matrix and
Aquaphor.RTM.. Cross-sections of the wounds were examined after
five days. Granulation tissue was stimulated in all test cases, as
measured by tissue staining (data not shown, but available).
Oasis.RTM. SIS matrix and the microporous gel show similar, low
acute multinucleated giant cell (MNGC) formation (while
Aquaphor.RTM. shows none), see FIG. 10A. Acute inflammation was
reduced in the wound beds receiving the microporous gel when
compared to Oasis.RTM. SIS matrix to Aquaphor.RTM., see FIG. 10B.
After 14 days of healing, wound atrophy was reduced by both the
Oasis.RTM. SIS matrix and the microporous scaffold, see FIG. 10C.
Cross-section histology showed the wound beds were completely
filled by all the microporous gel 5 days after treating, while
defects remain for both the Oasis.RTM. SIS matrix and the
Aquaphor.RTM. treated wounds.
[0307] Wound re-epithelialization and tissue fibrosis were examined
in tissue after 14 days of healing. Complete re-epithelialization
was seen for all wounds treated with Oasis.RTM. SIS matrix,
Aquaphor.RTM., or the microporous gel, see FIG. 11A. When examining
the reformed tissue after 14 days, pathologic scoring indicated
that tissue replacing the microporous scaffold exhibited less
alignment in the collagen fiber bundles, and less dense bundling,
indicative of tissue architecture different than that of fibrous
scar tissue, as compared to the other cohorts (Oasis.RTM. SIS
matrix, Aquaphor.RTM.). Quantification of fibrosis scoring is
presented in FIG. 11B.
[0308] Augmentation of wound healing vascularization by the MAP gel
was observed. Measurements of vessel ingrowth 5 days after healing
showed that both Oasis.RTM. SIS matrix and the microporous scaffold
promoted increased depth of vascular penetration into the wound
site (or scaffold), compared to Aquaphor.RTM. standard care, (data
not shown, but available). Vessel ingrowth quantification shows
statistically significant augmentation of vascularization by
Oasis.RTM. SIS matrix and the microporous scaffold, see FIG. 12A.
High magnification images showed ingrowing vessels in the
Oasis.RTM. SIS matrix and microporous scaffold cohorts, (data not
shown, but available). Both the Oasis.RTM. SIS matrix and
microporous scaffold microporous scaffold led to larger caliber
vessel formation in healed tissue after 14 days, compared to
Aquaphor.RTM. treatment, (data not shown, but available).
Aquaphor.RTM. forms typical scar-like small vessels, averaging 5-10
.mu.m in diameter (.about.capillary size). Both Oasis.RTM. SIS
matrix and the microporous scaffold promote larger vessel
formation, see FIG. 12B, and while these tissues also contain
capillaries, the percentage of vessels larger than 10 .mu.m in
diameter significantly increases compared to Aquaphor.RTM. treated
wounds. See FIG. 12C.
[0309] Both microporous gel injections and bilateral non-porous
hydrogel injections (chemically identical but no microporous
structure) were collected after 38 days in vivo and qualitatively
assessed for tissue integration. The non-porous flowable hydrogel
(Oasis.RTM. SIS matrix) exhibited virtually no tissue ingrowth,
with consistent MNGCs surrounding the material edge, typical of the
Foreign Body Response. Microporous gel injections showed no
detectable inflammation or MNGC presence around the injection
periphery, almost complete tissue integration, and significant
material degradation. The presence of large vessels with intimal
walls, and web-like dermal tissue indicated non-fibrous tissue
formation de novo within the injection site (data not shown, but
available).
Example 4
Administration of a Microporous Gel to a Site of a Cardiac
Pacemaker
[0310] A physician performs surgery on a patient to place a
pacemaker in the chest of the patient. The physician inserts the
pacemaker in the left shoulder area where an incision is made below
the collar bone creating a small pocket where the pacemaker battery
pack and part of the leads are actually housed in the patient's
body. The lead is fed into the heart through a large vein. Either:
(i) After the pacemaker is inserted, a solution containing microgel
particles and an annealing agent are applied to the incision site
or (ii) a solution containing microgel particles and an annealing
agent are applied to the incision site, followed by inserting the
pacemaker. In either condition (i) or (ii), the solution flows
around the pacemaker and fills any void between the pacemaker and
surrounding tissue. The solution also contains an antibiotic, an
analgesic, an anti-inflammatory agent and an anti-fibrotic agent.
The surgical site is exposed to light and the microgel particles
anneal to form a microporous scaffold. Alternatively,
heteroannealing takes place, and light is unnecessary. The surgical
site is sewn up. The patient heals quickly, experiences little pain
or discomfort, and does not develop any infection at the surgical
site. Eight years later, the physician creates another incision in
the chest to replace the battery in the pacemaker. The physician
notices that the pacemaker is integrated with the surrounding
tissue better than a pacemaker in a patient that does not receive
the microporous gel system. The physician also notices that there
is less scar tissue around the pacemaker relative to a pacemaker in
a patient that does not receive the microporous gel system. It is
easier for the physician to remove or replace the pacemaker battery
pack or leads, and the surgery time is reduced for this
procedure--reducing the risk of infection during the procedure.
Example 5
Spinal Cord Stimulation Implant for Spastic Cerebral Palsy
[0311] A surgical implant of electrodes for lateral cord
stimulation is employed in patients with spastic cerebral palsy
with the aim to improve tonus, motor function and speech. A
unilateral hemilaminectomy is performed at C3-C4 level, starting
from 4th cervical spinous process. A multicontact electrode is
placed on the lateral surface of the spinal cord. The multicontact
electrode is connected to a subcutaneously implanted pulse
generator (IPG). In order to implant the IPG, a surgical void is
created in the torsos of each patient. The IPG is placed within the
surgical void. However, there is remaining space in the surgical
void that is not filled by the IPG. A solution containing microgel
particles and an annealing agent are applied to the incision site.
The solution flows around the IPG and fills any void between the
IPG and surrounding tissue. Less solution is used in patients where
there is less remaining space as compared to more solution used in
patients where there is more remaining space. In this way, the
microporous gel system adapts the same device (e.g., size, shape)
to all patients. Alternatively, a solution containing microgel
particles and an annealing agent are applied to the incision site
prior to the placement of the IPG, and excess microgel particles
are easily removed after IPG placement. The solution also contains
an antibiotic, an analgesic, an anti-inflammatory agent and an
anti-fibrotic agent. The surgical site is exposed to light and the
microgel particles anneal to form a microporous scaffold.
Alternatively, heteroannealing takes place, and light is
unnecessary. The surgical site is sewn up. A post-operative
evaluation is performed every 30 days for the next six months. The
patients heal quickly, experience little pain or discomfort, and do
not develop any infection at the surgical site. The devices work
well, improving tonus, motor function and speech. If the device
requires any re-intervention, the physician is able to access the
device more easily than a patient that did not receive the
microporous system, reducing surgical times and risks associated
with that surgery.
Example 6
Cardioverter-Defibrillator Implant for Heart Arrhythmia
[0312] A cardioverter-defibrillator is implanted under the skin in
the left upper chest of a patient with a ventricular arrhythmia.
Either: (i) After the cardioverter-defibrillator is inserted, a
solution containing microgel particles and an annealing agent are
applied to the incision site or (ii) a solution containing microgel
particles and an annealing agent are applied to the incision site,
followed by inserting the cardioverter-defibrillator. In either
condition (i) or (ii), the solution flows around the
cardioverter-defibrillator and fills any void between the
cardioverter-defibrillator and surrounding tissue. Risk of a venous
obstruction such as upper extremity deep venous thrombosis and
pulmonary embolism is historically high in patients receiving these
devices. Thus, the solution contains an antithrombotic agent. The
surgical site is exposed to light and the microgel particles anneal
to form a microporous scaffold. Alternatively, heteroannealing
takes place, and light is unnecessary. The surgical site is sewn
up. The antithrombotic agent is released from the microporous
scaffold over the next few weeks as the patient recovers. The
patient does not develop or experience a vascular occlusion.
Example 7
Testing Shelf-Life Stability of a Microporous Gel System
[0313] The shelf life and stability of the microporous scaffold is
tested and validated using real-time and elevated temperature
methods. Shelf life at 25.degree. C., 50.degree. C., and
100.degree. C. are determined by exposing the scaffold to these
temperatures followed by undergoing the annealing process and
measuring the increase in compressive modulus of the scaffold after
annealing (compared to material that has not been exposed to
elevated temperature and has been freshly prepared (no time passing
since manufacture and measurement). Analytical methods (such as
HPLC/DAD to measure peptide and light absorbing chemical components
and GPC to measure polymeric chemical components) are also used to
quantitate the shelf-life stability of the scaffold. After
real-time and elevated temperature treatments, the scaffold is
rinsed in aqueous buffer to extract degraded components, and that
buffer is tested using the analytical methods to detect degradation
products. Elevated temperatures (100.degree. C.) can be used to
accelerate the stability process, where stability over short times
at 100.degree. C. indicate stability over longer times at
25.degree. C.
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