U.S. patent application number 15/442911 was filed with the patent office on 2017-11-16 for advanced functional biocompatible polymeric matrix containing nano-compartments.
The applicant listed for this patent is University of Maryland, College Park. Invention is credited to Matthew B. Dowling, Gregory F. Payne, Srinivasa R. Raghavan, Chao Zhu.
Application Number | 20170326169 15/442911 |
Document ID | / |
Family ID | 39853934 |
Filed Date | 2017-11-16 |
United States Patent
Application |
20170326169 |
Kind Code |
A1 |
Dowling; Matthew B. ; et
al. |
November 16, 2017 |
Advanced functional biocompatible polymeric matrix containing
nano-compartments
Abstract
The present invention provides a novel biomaterial which is a
hybrid, self-assembling biopolymeric networked film that is
functionalized through hydrophobic interactions with vesicles
loaded with bioactive agents. The biomaterial compound is a
polymeric network of hydrophobically modified chitosan scaffolds
that is taken from solution and formed as a solid film. This solid
state film is capable of hydrophobic interactions with the
functionalized vesicles. The vesicles include one or more lamellar
structures forming one or more nano-compartments that are capable
of containing similar or alternative active moieties within. Use of
the film results in a degradation of the chitosan scaffold thereby
releasing the active moieties within the vesicles from the
scaffold. Application of the current invention occurs through
various delivery mechanisms and routes of administration as will be
described herein.
Inventors: |
Dowling; Matthew B.;
(Washington, DC) ; Raghavan; Srinivasa R.; (Silver
Spring, MD) ; Payne; Gregory F.; (Cockeysville,
MD) ; Zhu; Chao; (McLean, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
University of Maryland, College Park |
College Park |
MD |
US |
|
|
Family ID: |
39853934 |
Appl. No.: |
15/442911 |
Filed: |
February 27, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14754600 |
Jun 29, 2015 |
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15442911 |
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12077173 |
Mar 17, 2008 |
9066885 |
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14754600 |
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60895221 |
Mar 16, 2007 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61L 26/0023 20130101;
A61K 9/127 20130101; A61K 47/543 20170801; A61L 27/20 20130101;
A61L 2300/216 20130101; A61L 2300/418 20130101; A61K 47/61
20170801; A61P 17/02 20180101; A61K 31/722 20130101; A61K 9/1271
20130101; A61K 47/56 20170801; A61K 47/69 20170801; A61L 2300/626
20130101; A61L 2300/232 20130101; A61L 2400/12 20130101; C08L 5/08
20130101; C08L 5/08 20130101; A61L 27/20 20130101; A61L 2400/04
20130101; A61K 9/7007 20130101; A61L 26/0023 20130101 |
International
Class: |
A61K 31/722 20060101
A61K031/722; A61K 47/69 20060101 A61K047/69; A61K 47/56 20060101
A61K047/56; A61L 26/00 20060101 A61L026/00; A61K 9/127 20060101
A61K009/127; A61K 9/70 20060101 A61K009/70; A61K 47/61 20060101
A61K047/61; A61L 27/20 20060101 A61L027/20; A61K 9/127 20060101
A61K009/127 |
Claims
1. A solution, comprising: a chitosan derivative with one or more
hydrophobic moieties covalently attached to the chitosan, wherein
said moieties are organic compounds with a backbone of at least six
and no more than thirty six carbon atoms.
2. The solution of claim 1 is in the form of one of a lotion, a
creams, and a gels.
3. The solution of claim 1, wherein <10% of available amines in
the chitosan are occupied by the one or more hydrophobic
moieties.
4. The solution of claim 1, is used to treat chronic wounds and
burns.
5. The solution of claim 1, in the form of a liquid drink for oral
ingestion.
6. The solution of claim 5, wherein <10% of available amines in
the chitosan are occupied by the one or more hydrophobic
moieties.
7. A method for the treatment of wounds comprising applying a
solution directly to a wounded or inflamed area; wherein the
solution comprises a chitosan derivative with one or more
hydrophobic moieties covalently attached to the chitosan, said
moieties are organic compounds with a backbone of at least six and
no more than thirty six carbon atoms.
8. The method of claim 7, wherein the solution is in the form of
one of a lotion, a cream, and a gel.
9. The method of claim 7, wherein the hydrophobic moieties occupy
<10% of available amines in the chitosan.
10. The method of claim 7, wherein the wounded or inflamed area is
hemorrhaging.
11. The method of claim 7, the wounded or inflamed area is a
chronic wound.
12. The method of claim 7, wherein the wounded or inflamed area is
a burn.
13. The method of claim 7, wherein the solution self-assembles to
treat the wounded or inflamed area.
14. The method of claim 7, wherein the solution uses strong
bioadhesion to treat the wounded or inflamed area.
15. The method of claim 7, wherein the solution readily binds to
negatively charged surfaces.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority under 35 U.S.C.
.sctn.119 to the U.S. Provisional Application Ser. No. 60/895,221,
filed on Mar. 16, 2007, which is herein incorporated by reference
in its entirety.
FIELD OF THE INVENTION
[0002] The present invention generally relates to the field of
biopolymers and particularly to hydrophobic modification of
biopolymers for solid state film formation and the association of
these biopolymers with vesicles (liposomes).
BACKGROUND OF THE INVENTION
[0003] A derivative of glucose found throughout the natural world,
Chitin (C.sub.8H.sub.13O.sub.5N).sub.n, nature's second most
abundant compound next to cellulose, is naturally found as a
polysaccharide or long-chain polymer composed of repeating
monomeric units of N-acetylglucosamine in beta-1,4 linkage.
##STR00001##
[0004] Chitin Structure Showing Two of the Repeating
N-Acetylglucosamine Units
[0005] Chitin is a non-toxic, biocompatible and biodegradable
polymer that serves a structural function and contributes strength
to those structures of which it is a component feature. For
instance, chitin is a main component found in the shells
(exoskeletons) of various animals like crab, lobster, and shrimp
(crustaceans); ants, beetles, and butterflies (insects); the beaks
of squid and octopi (cephalopods); and the cell walls of fungi, to
name a few. Chitin has been used for industrial, medicinal,
agricultural, cosmetic, and numerous other purposes providing
advantageous characteristics in these various settings.
[0006] Chitosan is a deacetylated derivative of chitin that retains
the non-toxic, biocompatible and biodegradable characteristics of
its parent. Chitosan is a linear polysaccharide composed of
repeating .beta.-(1-4)-linked D-glucosamine monomeric units.
Chitosan and its derivatives have been widely studied for their
potential applications in various fields, such as industry,
medicine, biotechnology, cosmetics and agriculture due to their
generally acidic characteristics and their readily reactive
nature.
[0007] Nanotechnology is the name most often associated with the
field of applied science and technology that aims to control matter
on the atomic and molecular scale. Thus, typical size ranges for
the components being worked with and "devices" being constructed
range from 1 to 100 nanometers. The "devices" may be anything from
mechanical, to chemical, to biological constructs. Nano-robots that
can perform tasks through physical movement and manipulation of
their surrounding environment and nano-therapeutics that are
synthesized within biomaterial constructs to provide biologically
active molecular components/active moieties and thus provide
chemical/biological interaction with their surrounding environment
are just a couple of the numerous and varied examples of the
current application of nanotechnology. Today many such
"nano-constructs" are known and being employed in numerous fields
to accomplish various tasks.
[0008] Vesicles are hollow spherical structures, that may be
nano-scale in size, formed by the self-assembly of surfactants,
lipids, or block copolymers in aqueous solution. They have long
been a scientific curiosity because of their structural resemblance
to primitive biological cells. More importantly, vesicles are of
technological interest for application ranging from drug delivery
and controlled release to bioseparations and sensing. Many of these
applications rely upon the ability of vesicles to entrap desired
chemicals (i.e., functionalization) in their interior and
thereafter release these chemicals to the external medium in a
controlled manner. Thus, vesicles, (e.g. liposomes, in the case of
lipids being the substituent molecules), as defined by their
membrane structures, play many roles in the world of chemical and
organic reactions.
[0009] Currently, the use of various biopolymer backbones, such as
chitosan lattices/networks or other polysaccharide/polypeptide
networks, in combination with functionalized vesicle/liposomes are
known to be useful bioactive complexes for numerous applications
which may be contained/loaded in vesicle/liposome structures.
Therefore, it would be desirable to provide novel bioactive
complexes that were able to promote increased ease of these
bioactive complexes formation and increased functionality of such
complexes.
SUMMARY OF THE INVENTION
[0010] The current invention is a novel hybrid composition of
matter. In preferred exemplary embodiments, the composition of
matter is networked film matrix of hydrophobically modified
biopolymer (chitosan) backbone that hydrophobically interacts, in a
self assembling manner, with vesicles (liposomes or micelles) that
may be functionalized. In other preferred exemplary embodiments,
the current invention provides a system and kit that utilize the
novel film matrix. In still further preferred exemplary
embodiments, novel methods of constructing and using the film
matrix of the current invention are provided.
[0011] In a first preferred exemplary embodiment, the film is a
solid-state matrix of hydrophobically modified chitosan (the
"hm-Chitosan film"). This readily reactive matrix, in a second
preferred exemplary embodiment of the current invention, is capable
of being functionalized, through the attachment of vesicles
(liposomes and/or micelles) to form a solid-state, functionalized
biopolymer networked film (the "functionalized film"). The vesicles
may be empty "sacs" or may be functionalized in various manners,
including containing various bioactive agents or moieties either as
part of the membrane layer or stored within an interior cavities or
environments. The size of these vesicles and/or the storage
locations for the bioactive agents within may be on a nano-scale or
larger.
[0012] The exemplary systems may include either the hm-Chitosan
film or functionalized film being employed within a particular
environment. For instance, the system may be a wound healing system
where the functionalized film is provided as an elastic, flexible
"wrap" that may be placed in direct contact with the wounded area
or location. The novel films and systems have many important
features, for example: 1. the readily reactive hydrophobically
modified biopolymeric network film that provides a wide range of
functionalization options and capabilities when functionalized by
interaction with vesicles, such as liposomes; and 2. the diverse
variety of bioactive agents (molecules) of interest that may be
loaded into the nano-compartments of the liposomes for packaging
and release into a determined environment.
[0013] It is also another preferred exemplary embodiment of the
current invention to provide a method of forming or fabricating a
biopolymer film that includes complexing a biopolymer with an
amphiphilic compound (hydrophilic heads and hydrophobic tails), and
then dehydrating the hydrophobically modified biopolymer into a
solid state film. The solid state is preferably a film matrix of
amphiphilic biopolymers (hm-Chitosan). The current invention may be
further exemplified by the preferred embodiment wherein the solid
state matrix is functionalized by interaction with functional
vesicles or liposomes including bioactive agents or moieties. The
functionalization of the solid state matrix with the biologically
active liposomes may preferably occur by hydrophobic interaction
between the hydrophobic tail of the hm-Chitosan film matrix and
vesicles/liposomes. Another exemplary functional result may be that
the liposomes serve to cross-link the hm-Chitosan matrix that
constitute the film.
[0014] In another exemplary preferred embodiment of the current
invention, a method of using a hm-Chitosan film is provided. The
hm-Chitosan film for use in this method includes a matrix of
hydrophobically modified chitosan biopolymers that are presented in
a solid state film. The method of using this solid state
hm-Chitosan film matrix includes, in an exemplary preferred
embodiment, interacting the hm-Chitosan film with a liposome
(vesicle) containing solution, whereby hydrophobic interaction
allows for the self-assembly of a functionalized film. Another
exemplary method of use may include the application of the
functionalized film to an area whereby active ingredients stored by
or contained within the liposomes may be released to perform their
function.
[0015] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the invention as
claimed. The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate an embodiment of
the invention and together with the general description, serve to
explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The numerous advantages of the present invention may be
better understood by those skilled in the art by reference to the
accompanying figures in which:
[0017] FIGS. 1A and 1B are structural and graphical representations
of a hydrophobically modified chitosan (hm-Chitosan) biopolymer
film in accordance with an exemplary embodiment of the current
invention;
[0018] FIG. 2 is an illustration representing a readily reactive,
dehydrated, solid state hm-Chitosan film matrix, wherein the
hm-chitosan "backbone" or "scaffold" is capable of being cast into
a film and the amphiphilic compounds allow for hydrophobic
interaction with vesicles or liposomes to provide a functionalized
film in accordance with an exemplary embodiment of the present
invention;
[0019] FIG. 3 is an illustration representing an hm-Chitosan film
matrix wherein a plurality of liposomes (vesicle) cross-link the
hm-Chitosan scaffolds;
[0020] FIG. 4 is an illustration providing a representation of
hydrophobic interaction between the hm-Chitosan and liposome
(vesicle) bi-layer;
[0021] FIG. 5 is an illustration representing a solid-state
functionalized film, including the hm-Chitosan bound with the
vesicles based upon hydrophobic interaction of the hm-Chitosan
scaffolds with the functionalized liposomes (vesicles), wherein the
liposomes contain bioactive agents and/or moieties, and further
illustrating the cross-linking of the numerous hm-Chitosan
scaffolds by the liposomes;
[0022] FIG. 6 is an illustration of the two phases of formation of
the novel composition of matter of the current invention. PHASE I:
a formation or fabrication process of the solid-state, hm-Chitosan
film matrix; PHASE II: a formation or fabrication process of a
functionalized film of the current invention, wherein the
hm-Chitosan film matrix from PHASE I is used to form this secondary
composition of matter;
[0023] FIG. 7 is an illustration of another exemplary process of
forming a functionalized film matrix, wherein the solid-state, dry
film matrix of hm-chitosan has functionalized liposomes introduced
to it, wherein the liposome may include nothing or various moieties
or therapeutics or other biologically (pharmacologically) active
agents, and through hydrophobic interactions form a complex that
provides the functionalized film matrix is formed;
[0024] FIG. 8 is an illustration of another exemplary process of
forming a functionalized film matrix in accordance with an
exemplary embodiment of the current invention;
[0025] FIG. 9 provides an illustrative representation of an
exemplary use of the functionalized film matrix of the current
invention wherein an "injured" area has the solid-state,
functionalized biopolymeric film matrix applied directly to the
"injured" area, whereupon such direct application the active
ingredients contained in the liposomes are released into the
"injured" area to promote healing as shown in FIG. 10;
[0026] FIG. 10 is an illustration of the process of releasing the
functionalized vesicles from the hm-Chitosan film matrices via
enzymatic degradation in order to release the vesicles into an
environment;
[0027] FIG. 11 is an illustration of another exemplary use of the
functionalized film matrix of the current invention;
[0028] FIG. 12 is a graphical representation of a method of
fabricating or forming a hm-Chitosan film matrix in accordance with
an exemplary embodiment of the current invention; and
[0029] FIG. 13 is a graphical representation of a method of
fabricating or forming a functionalized film in accordance with an
exemplary embodiment of the current invention.
[0030] FIG. 14 is a diagram of a liposome.
[0031] FIG. 15 is a diagram of a lipid bilayer in a liposome.
[0032] FIG. 16 is a schematic showing anchoring of vesicles to
hm-chitosan.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Reference will now be made in detail to the presently
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings.
[0034] Referring generally now to FIGS. 1 through 11, exemplary
embodiments of the present invention are shown. In preferred
embodiments, a novel solid-state, hm-Chitosan film matrix including
numerous hydrophobically modified chitosan compounds, is shown in
FIGS. 1A, 1B, and 2. These novel compounds consist of a biopolymer
(e.g., chitosan) backbone that includes a hydrophilically reactive
functional group (e.g., amino groups) that binds with the
hydrophilically reactive head groups (e.g., carbonyl functional
group) of an amphiphilic compound (e.g., aldehyde). The head group
is further associated with a hydrophobic tail group. In the current
embodiment, the hydrophobic tail may be for example a hydrocarbon.
Thus, a hydrophobic tail is associated with the biopolymer's
chitsan backbone providing the hydrophobic modification to the
molecule that extends from the backbone and may interact with the
surrounding environment in numerous ways, such as through
hydrophobic interaction with other hydrophobic tails on the
backbone or through hydrophobic interaction with other molecules
and/or structures. Typically, and for the purposes of the preferred
embodiments of the instant application, these hydrophobically
modified polymers (biopolymers) are referenced as being composed of
a chitosan "backbone", "scaffold", and/or "lattice". Thus, the
backbone of the hydrophobically modified biopolymer film matrix of
the preferred embodiments of the current invention is the
biopolymer chitosan. Other biopolymers which include similar
characteristics of the chitosan backbone may be employed with
departing from the scope and spirit of the instant invention.
[0035] Chitosan is a deacetylated derivative of chitin, wherein the
degree of deacetylation (% DA) may range from 60-100% and
determines the charge density. Chitosan is a linear polysaccharide
composed of repeating .beta.-(1-4)-linked D-glucosamine monomeric
units.
##STR00002##
Chitosan Structure Showing Three of the Repeating Beta-(1-4)-Linked
D-Glucosamine Units (Deacetylated)
[0036] These repeating monomeric units include a free amino group
(functional group) and may make molecules or compounds containing
chitosan or its derivatives readily reactive. The hydrophic
modification of the chitosan backbone is through the association of
an amphiphilic compound with the amino group, such that the
hydrophobic tail of the amphiphilic compound is bound with the
hydrophilic backbone structure. As seen in FIGS. 1B and 2, this
hydrophobically modified chitosan backbone (hm-Chitosan) may then
be cast into a film. In the preferred embodiment of FIG. 2,
numerous hm-Chitosan backbones may fill a solution which may then
be cast into a film forming the novel hm-Chitosan film of the
current invention. This film matrix is a solid-state or dried film
of the hm-Chitosan.
[0037] In a preferred embodiment shown in FIG. 6 (PHASE I) the
formation or fabrication of this novel solid-state, hm-Chitosan
film matrix is graphically represented. Thus, a first novel,
preferred embodiment of the current invention is a dried,
hm-Chitosan film or composition of matter which may be readily
reactive with additional molecules and/or compounds. It is
preferred that this composition of matter be prepared as a readily
reactive, solid-state film matrix for application and use in
various environments. However, various other implementation states
of the current invention as may be contemplated by those of
ordinary skill in the art are hereby assumed to fall within the
scope of the current invention.
[0038] In another preferred, alternative embodiment of a
composition of matter for the current invention, an hm-Chitosan
film matrix is bound with vesicles or liposomes through hydrophobic
interactions. FIGS. 3, 4, and 5 provide exemplary, graphic
illustrations representing a functionalized film of the current
invention which includes the hm-Chitosan bound with the liposomes.
Various exemplary, preferred embodiments of formation processes of
the functionalized film are shown in FIGS. 6 (PHASE II), 7, and 8.
Similar to the solid-state, hm-Chitosan film matrix identified
above, the functionalized networked film of the current invention
is a solid-state, dry networked functionalized film. The formation
processes, the cross-linking stabilizing effect that the vesicles
or liposomes have on the matrix of numerous hm-Chitosan based
films, and the "functionalization" or biological activity (e.g.,
pharmacological activity) of the vesicles or liposomes bound to the
hm-Chitosan backbone may provide significant advantages to the
current invention and such various component features are
understood to fall within the scope of the current invention. In
addition, FIG. 10 (described herein below) provides an exemplary
graphical representation of the degradative release of the
liposomes from the hm-Chitosan backbones, thus illustrating some of
the in situ activity that is made possible by the current
invention.
[0039] In alternative preferred embodiments, showing exemplary
functional applications and uses of the functionalized film of the
current invention, FIGS. 9 and 11 illustrate the current invention
as it can be constructed and/or embodied within as a patch,
bandage, and "wrap". As will be further described below herein,
these illustrative representations of application and use of the
current invention should not be read as limiting or exclusive and
that those of skill in the art will understand that the embodiments
within which the current invention may be employed may vary from
encapsulated therapeutics, to various composition of matter
formulations, to various "film" forms, to incorporation within
various types of devices and/or mechanical forms, without departing
from the scope and spirit of the current invention.
[0040] As used herein, functional group(s) (moiety or moieties) are
specific groups of atoms attached to a carbon backbone of organic
molecules that characterize the molecule and are responsible for
the molecule's chemical reactivity such that the same functional
group of atoms will generally undergo the same or similar chemical
reactions(s) regardless of the size of the molecule it is a part
of. The characteristics of chitosan and its derivatives typically
give them an overall pKa value of .about.6.5 and pH .about.6, thus
they are positively charged and soluble in acidic to neutral
solution. Further, these types of reactive characteristics are
often typical of strong bioadhesives, thus, chitosan and its
derivatives may be readily able to bind to negatively charged
surfaces, such as membranes (mucosal or otherwise), or molecules,
such as various functional groups or moieties.
[0041] Generally, and in preferred embodiments of the current
invention, the amino group or functional group for the chitosan
backbone is where the positive charge of the molecule is "located".
It is to be further understood that the chitsan scaffold may
include numerous functional groups in various locations about its
molecular structure. The amino functional group is typically where
the amphiphilic compound will bind thereby presenting its
hydrophobic tail to the outer environment and brining hydrophobic
modification to the chitosan backbone. Due to the cyclic nature of
the chitosan molecular structure the addition of the amphilic
compound may generally occur vai a process of nucleophilic
addition. This is opposed to linear or "straight" chain
hydrocarbons or aliphatic hydrocarbons, wherein the addition of
molecules or compounds to the backbone is generally referred to as
branching and the newly added organics as side-chains. It is to be
understood that the general principles and characteristics of
chemical bonding, such as those intra- and inter-molecular bonding
forces that are applicable for such chemical and/or electromagnetic
reactions and known to those skilled in the art, apply herein. Any
description regarding or reference to chemical or electromagnetic
bonding characteristics, such as anything related to orbitals,
valency, charge dispersion (location), electronegativities,
hydrophobic interactions, shall be understood to comply with the
generally accepted wisdom in the field as known by those of
ordinary skill in the art.
[0042] In a preferred embodiment of the current invention, and from
the PHASE I reaction process, as shown in FIG. 6, the chitosan
backbone is hydrophobically modified by an amphiphilic compound.
The amphiphilic compound, in a preferred embodiment, includes an
aldehyde functional group associated with a saturated hydrocarbon.
The formation process is graphically represented in FIG. 12, which
illustrates a first step 1205 as obtaining chitosan compound or
scaffold. This may be a solution containing numerous chitosan
scaffolds that are readily reactive through their amine functional
group. As shown, the chitosan may be formed or accomplished by the
deacetylation of a chitin compound. After obtaining the chitosan
compound of interest or a solution containing numerous such
compounds, in step 1210, an amphiphilic compound is bound to the
chitosan scaffold. In practical application, the amphiphilic
compounds may be contained within a solution which is then mixed
with the chitosan solution. The amphiphilic compounds bind through
their functional groups, preferably the aldehyde functional group,
with the amino functional group of the chitosan scaffolds. It is
noted that typically .ltoreq..about.10% of available amines will
react and bond with the amphiphilic compounds. In preferred
embodiments of the current invention, the percentage of amines that
react and bond with the amphiphilic compounds is in the range of
.about.1.5% to 4.5%. This may be largely influenced by problems
with solubility once the percentage of reacted amines goes over 5%.
Once this binding has occurred the hydrophobically modified
chitosan scaffold or backbone (hm-Chitosan) has been formed and now
in step 1215 the hm-Chitosan is cast into film. In the final step
1220, the hm-Chitosan film is dehydrated or dried providing a novel
solid-state, dry hm-Chitosan film matrix.
[0043] In current embodiments of the instant invention the
amphiphilic compound is a C.sub.12 aldehyde compound and it
hydrophobically modifies the chitosan backbone through hydrophilic,
covalent interaction with one of the available amino groups. This
type of amphiphilic group may be commonly referred to as a short
chain hydrophobe. It is understood that the C.sub.12 aldehyde
compound is an amphiphilic compound, having both a hydrophilic
(carbonyl) group (the "Head") and a hydrophobic (hydrocarbon) group
(the "Tail"). In the current embodiment, the basic formula for the
aldehyde compound bound to the chitosan backbone is shown in the
FIGS. 1A and 6 to be C.sub.12H.sub.25. Thus, the aldehyde
functional group includes a hydrophilic, reactive C--O type
(carbonyl group) bond at the Head and a hydrophobic, hydrocarbon
Tail.
[0044] The binding of the amphiphilic compound with the chitosan
scaffold occurs through a hydrophilic interaction, wherein the
hydrophilic, aldehyde Head group interacts with the hydrophilic
amino functional group of the chitosan scaffold. In a preferred
embodiment, the reaction process between these two functional
groups is a nucleophilic addition reaction process known as an
alkylimino-de-oxo-bisubstitution organic reaction wherein a
carbonyl compound interacts with an amine to form an imine, as
follows:
##STR00003##
The imine may then be converted to a stable secondary amine by the
addition of a mild reducing agent such as sodium cyanoborohydride
(NaBH.sub.3(CN)).
[0045] This is a two step reaction process that is acid catalyzed
wherein the first step is an addition reaction forming an
hemiaminal intermediate which transfers a proton from the nitrogen
to the oxygen and then in the second step a dehydration or
condensation reaction takes place and a water molecule is removed
from the intermediate. Overall, the current invention proceeds to
establish two new covalent bonds between the nitrogen of the amino
group and the carbon of the carbonyl group. This reaction process
promotes increased stability of the hm-Chitosan molecule as a lower
energy state is reached as compared to a molecule where both amine
and aldehyde functional groups are present.
[0046] In the current embodiment the association of the Head group
with the amino group occurs through the formation of a new covalent
bond, forming a strong double bond between the nitrogen atom of the
amine and the carbon atom of the aldehyde. It is contemplated that
other types of associations may be structured between the chitosan
scaffold amino group and the aldehyde as may be desired, thus, the
current exemplary embodiment should not be read as limiting or
exclusive.
[0047] The amphiphilic compound, because of the C--O bond contained
therein, is generally described and classified together with other
types of functional groups that contain a carbon-oxygen bond
(C--O). Further, it is known that the activity of the aldehyde
functional group comes from the carbon atom double-bonded to an
oxygen atom C.dbd.O, which is generally described and classified as
a carbonyl group or carbonyl functional group. The carbonyl group
classification is a characterization that applies to many different
types of compounds, including the following:
TABLE-US-00001 Carbonyl Carboxylic Compounds Aldehyde Ketone acid
Ester Structure ##STR00004## ##STR00005## ##STR00006## ##STR00007##
General RCHO RCOR' RCOOH RCOOR' Forumla Carbonyl Acyl Acid
Compounds Amide Enone chloride anhydride Structure ##STR00008##
##STR00009## ##STR00010## ##STR00011## General RCONR'R''
RC(O)C(R')CR''R''' RCOCL (RCO).sub.2O Formula
[0048] It is contemplated that those of ordinary skill in the art
may utilize alternative carbonyl functional groups as the
hydrophilic Head group of an amphiphilic compound to react with the
amino group of the chitosan backbone to provide the association of
the amphiphilic compound with the chitosan backbone in a manner
similar to that provided by the aldehyde compound. Thus, it is
contemplated that the chitosan backbone may be hydrophobically
modified through interaction with various, alternative organic
compounds which may include alternative carbonyl functional
groups.
[0049] In the current embodiment, the amphiphilic compound is
described as further including a hydrocarbon Tail group associated
with the reactive aldehyde (C.dbd.O) Head group. This hydrocarbon
chain has a defining and useful characteristic in that it is
hydrophobic in nature and therefore insoluble in water and capable
of hydrophobic interaction. Hydrophobicity refers to a physical
property of a molecule (i.e., hydrophobe) that is repelled from
water because of its non-polar (no electric charge) nature. Thus,
hydrophobes are "driven" together because they are unable to form
polar (electrically charged) bonds with other molecules. For
example, water molecules are electrically polarized and in a
solution of hydrophobes and water, the water molecules will form
hydrogen bonds with other water molecules and repel the
nonpolarized hydrophobes. It is this repulsive, thermodynamic force
and effect that is commonly referred to as the hydrophobic
interaction, even though the energy is coming from the hydrophilic
molecules.
[0050] The hydrophobic interaction is also a noncovalent type of
chemical bond where the atoms and/or molecule(s) involved do not
share pairs of electrons as the driving force of the bonding
interaction, instead they use a more dispersed variation of
electromagnetic interaction to hold the molecules or parts of
molecules together, commonly referred to as a thermodynamic
effect.
[0051] As described previously, the hydrocarbon chain is commonly
referred to as a short chain hydrophobe. This generic reference is
not intended to provide a particular limit on the length of the
hydrophobic Tail group that may be employed with the current
invention as any length hydrocarbon chain may fall within the scope
and spirit of the current invention. It is to be understood that in
the preferred embodiments of the invention the number of carbon
atoms contained in the short chain hydrophobic Tail group of the
amphiphilic compound may range from a minimum number of two (2) to
a maximum number of fifty (50). In preferred embodiments of the
current invention the number of carbon atoms in the hydrophobic
Tail group may range from six (6) to thirty-six (36) and that more
preferably the number of carbon atoms included in the hydrophobic
Tail group is twelve (12). As will be described below, the number
of carbon atoms, which define the length of the hydrophobic Tail
group, may be dependent on the size of the hydrophobic cavity
within the liposome (vesicle) bi-layer membrane.
[0052] Generally, the hydrophobic cavity is defined by the length
of the hydrophobic chains extending from the hydrophilic heads of
the lipids that form the bi-layer membrane. In the preferred
embodiments, the hydrophobic chains of these lipids include
eighteen (18) carbon atoms each. Therefore, the overall size (i.e.,
width) of the hydrophobic cavity is thirty-six carbon atoms long.
Thus, it is generally preferred that the length (i.e., carbon
backbone) of the hydrophobic Tail group of the amphiphilic compound
that hydrophobically modifies the chitosan scaffold not exceed
thirty-six (36) carbon atoms.
[0053] As used herein, hydrocarbon(s) are any organic molecule(s)
or compound(s) with a "backbone" or "skeleton" consisting entirely
of hydrogen and carbon atoms and which lack a functional group.
Thus, these types of compounds are hydrophobic in nature, unable to
react hydrophilically, and therefore provide an opportunity for
hydrophobic interaction. The hydrophobic interaction capability of
the amphiphilic compound bound to the chitosan backbone may provide
significant advantage to the current invention when compared to the
prior art in that the interaction of the hm-Chitosan with the
liposomes or vesicles is a self-driven, thermodynamic process
requiring less energy input. Thus, regardless of any particular
form of the Tail group of the amphiphilic compound, so long as it
provides the opportunity for hydrophobic interaction with the
vesicles or liposomes it falls within the scope and spirit of the
current invention.
[0054] Hydrocarbons, which are hydrophobic, may form into various
types of compounds/molecules, such as gases (e.g. methane and
propane), liquids (e.g., hexane and benzene), waxes or low melting
solids (e.g., paraffin was and naphthalene), polymers (e.g.,
polyethylene, polypropylene and polystyrene), or biopolymers.
Currently, hydrocarbons may be classified as follows: [0055] 1.
Saturated Hydrocarbons (alkanes) are composed entirely of single
bonds between the carbon and hydrogen atoms and are denoted by
(assuming non-cyclic structures) the general formula
C.sub.nH.sub.2n+2. These types of compounds are the most simple of
the hydrocarbons and are either found as linear or branched species
of unlimited number. [0056] 2. Unsaturated Hydrocarbons include one
or more multiple bonds between carbon atoms of the compound, such
as double bonds (alkenes-C.sub.nH.sub.2n) or triple bonds
(alkynes-C.sub.nH.sub.2n+2). These multiple bonds create carbon
atoms which are also commonly referred to as hydrogenated in that
they are in need of the addition of further hydrogen atoms. [0057]
3. Cycloalkanes consist of only carbon and hydrogen atoms are
cyclic or "ring-shaped" alkane hydrocarbons denoted by the general
formula C.sub.nH.sub.2(n+1-g) where n=number of C atoms and
g=number of rings in the molecule. Cycloalkanes are saturated
because there are no multiple (double or triple) C--C bonds to
hydrogenate (add more hydrogen to). [0058] 4. Aromatic
Hydrocarbons, also known as arenes, are hydrocarbons that contain
at least one aromatic ring and may be denoted by the formula
C.sub.nH.sub.n, wherein at a minimum n=6. Arenes (e.g.,
Benzene-C.sub.6H.sub.6) or Aromatic Hydrocarbons include a
molecular structure which incorporates one or more planar sets of
six carbon atoms connected by delocalized electrons numbering the
same as if they consisted of alternating single and double covalent
bonds. From this basic classification system there exist many
derivatives and further types of compounds that build therefrom.
For example, numerous and varied compounds include more than one
aromatic ring and are generally referred to as polyaromatic
hydrocarbons (PAH); they are also called polycyclic aromatic
hydrocarbons and polynuclear aromatic hydrocarbons. Various
alternative/derivative forms of the saturated or unsaturated
cycloalkanes, and aromatic hydrocarbons as are known and
contemplated by those skilled in the art may be employed with the
current invention and should be read as falling within the
contemplated scope of the current invention.
[0059] Various types of other hydrophobic, organic compounds may
generally include hydrocarbon backbones but may also include other
types of atoms and/or incorporate/bind to other compounds/molecular
structures that incorporate other types of atoms than just carbon
and hydrogen. Thus, another classification system has developed by
which organic compounds with generally hydrocarbon backbones but
bound with other types of molecules may be separated, wherein such
compounds may be designated either aromatic or aliphatic. Thus,
compounds composed mainly, substantially or at least partially, but
not exclusively of carbon and hydrogen may be divided into two
classes: [0060] 1. aromatic compounds, which contain benzene and
other similar compounds, and [0061] 2. aliphatic compounds (G.
aleiphar, fat, oil), which do not. In aliphatic compounds, carbon
atoms can be joined together in straight chains, branched chains,
or rings (in which case they are called alicyclic). They can be
joined by single bonds (alkanes), double bonds (alkenes), or triple
bonds (alkynes). Besides hydrogen, other elements can be bound to
the carbon chain, the most common being oxygen, nitrogen, sulfur,
and chlorine. Those of ordinary skill in the art will recognize
that other molecules may also be bound to the carbon chains and
that compounds of such heteroatomic structure are contemplated as
falling within the scope of the current invention.
[0062] The hydrophobic Tail group of the amphiphilic compound bound
to the chitosan backbone of the current invention is capable of
branching and/or allowing the inclusion of side chains onto its
carbon backbone. This may promote the hydrophobic interaction
between the hm-Chitosan and liposomes, as will be discussed further
below. It may be understood that the strength of the hydrophobic
interaction is based upon the available amount of "hydrophobes"
that may interact amongst themselves or one another. Thus, it may
further promote the hydrophobic effect by increasing the amount of
and/or "hydrophobic" nature of the hydrophobic Tail group that is
interacting. For instance, a hydrophobic Tail group, which in its
original form may include a hydrocarbon chain, may promote an
increase in its hydrophobicity (ability to hydrophobically bond and
strength of hydrophic interaction) by having a hydrophobic side
chain attach to one of the carbons of its carbon backbone. In a
preferred embodiment of the current invention, this may include the
attachment of various polycyclic compounds, which may include for
instance various steroidal compounds and/or their derivatives such
as sterol type compounds, more particularly cholesterol.
[0063] In alternative embodiments, the current invention
contemplates the use of various molecules and/or compounds that may
increase the hydrophobic interaction allowed between the Tail of
the amphiphilic compound and the bi-layer membrane of the
liposomes. The side chains may be linear chains, aromatic,
aliphatic, cyclic, polycyclic, or any various other types of
hydrophobic side chains as contemplated by those skilled in the
art. Some of the contemplated hydrophobic side chains may include
the following:
I. Linear Alkanes
TABLE-US-00002 [0064] Number of C atoms Formula Common name
Synonyms 1 CH.sub.4 Methane marsh gas; methyl hydride; natural gas
2 C.sub.2H.sub.6 Ethane dimethyl; ethyl hydride; methyl methane 3
C.sub.3H.sub.8 Propane dimethyl methane; propyl hydride 4
C.sub.4H.sub.10 n-Butane butyl hydride; methylethyl methane 5
C.sub.5H.sub.12 n-Pentane amyl hydride; Skellysolve A 6
C.sub.6H.sub.14 n-Hexane dipropyl; Gettysolve-B; hexyl hydride;
Skellysolve B 7 C.sub.7H.sub.16 n-Heptane dipropyl methane;
Gettysolve-C; heptyl hydride; Skellysolve C 8 C.sub.8H.sub.18
n-Octane dibutyl; octyl hydride 9 C.sub.9H.sub.20 n-Nonane nonyl
hydride; Shellsol 140 10 C.sub.10H.sub.22 n-Decane decyl hydride 11
C.sub.11H.sub.24 n-Undecane hendecane 12 C.sub.12H.sub.26
n-Dodecane adakane 12; bihexyl; dihexyl; duodecane 13
C.sub.13H.sub.28 n-Tridecane 14 C.sub.14H.sub.30 n-Tetradecane 15
C.sub.15H.sub.32 n-Pentadecane 16 C.sub.16H.sub.34 n-Hexadecane
cetane 17 C.sub.17H.sub.36 n-Heptadecane 18 C.sub.18H.sub.38
n-Octadecane 19 C.sub.19H.sub.40 n-Nonadecane 20 C.sub.20H.sub.42
n-Eicosane didecyl 21 C.sub.21H.sub.44 n-Heneicosane 22
C.sub.22H.sub.46 n-Docosane 23 C.sub.23H.sub.48 n-Tricosane 24
C.sub.24H.sub.50 n-Tetracosane tetrakosane 25 C.sub.25H.sub.52
n-Pentacosane 26 C.sub.26H.sub.54 n-Hexacosane cerane; hexeikosane
27 C.sub.27H.sub.56 n-Heptacosane 28 C.sub.28H.sub.58 n-Octacosane
29 C.sub.29H.sub.60 n-Nonacosane 30 C.sub.30H.sub.62 n-Triacontane
31 C.sub.31H.sub.64 n-Hentraiacontane untriacontane 32
C.sub.32H.sub.66 n-Dotriacontane dicetyl 33 C.sub.33H.sub.68
n-Tritriacontane 34 C.sub.34H.sub.70 n-Tetratriacontane 35
C.sub.35H.sub.72 n-Pentatriacontane 36 C.sub.36H.sub.74
n-Hexatriacontane 37 C.sub.37H.sub.76 n-Heptatriacontane 38
C.sub.38H.sub.78 n-Octatriacontane 39 C.sub.39H.sub.80
n-Nonatriacontane 40 C.sub.40H.sub.82 n-Tetracontane 41
C.sub.41H.sub.84 n-Hentetracontane 42 C.sub.42H.sub.86
n-Dotetracontane 43 C.sub.43H.sub.88 n-Tritetracontane 44
C.sub.44H.sub.90 n-Tetratetracontane 45 C.sub.45H.sub.92
n-Pentatetracontane 46 C.sub.46H.sub.94 n-Hexatetracontane 47
C.sub.47H.sub.96 n-Heptatetracontane 48 C.sub.48H.sub.98
n-Octatetracontane 49 C.sub.49H.sub.100 n-Nonatetracontane 50
C.sub.50H.sub.102 n-Pentacontane 51 C.sub.51H.sub.104
n-Henpentacontane 52 C.sub.52H.sub.106 n-Dopentacontane 53
C.sub.53H.sub.108 n-Tripentacontane 54 C.sub.54H.sub.110
n-Tetrapentacontane 55 C.sub.55H.sub.112 n- Pentapentacontane 56
C.sub.56H.sub.114 n-Hexapentacontane 57 C.sub.57H.sub.116 n-
Heptapentacontane 58 C.sub.58H.sub.118 n-Octapentacontane 59
C.sub.59H.sub.120 n- Nonapentacontane 60 C.sub.60H.sub.122
n-Hexacontane 61 C.sub.61H.sub.124 n-Henhexacontane 62
C.sub.62H.sub.126 n-Dohexacontane 63 C.sub.63H.sub.128
n-Trihexacontane 64 C.sub.64H.sub.130 n-Tetrahexacontane 65
C.sub.65H.sub.132 n-Pentahexacontane 66 C.sub.66H.sub.134
n-Hexahexacontane 67 C.sub.67H.sub.136 n-Heptahexacontane 68
C.sub.68H.sub.138 n-Octahexacontane 69 C.sub.69H.sub.140
n-Nonahexacontane 70 C.sub.70H.sub.142 n-Heptacontane 71
C.sub.71H.sub.144 n-Henheptacontane 72 C.sub.72H.sub.146
n-Doheptacontane 73 C.sub.73H.sub.148 n-Triheptacontane 74
C.sub.74H.sub.150 n-Tetraheptacontane 75 C.sub.75H.sub.152 n-
Pentaheptacontane 76 C.sub.76H.sub.154 n-Hexaheptacontane 77
C.sub.77H.sub.156 n- Heptaheptacontane 78 C.sub.78H.sub.158
n-Octaheptacontane 79 C.sub.79H.sub.160 n- Nonaheptacontane 80
C.sub.80H.sub.162 n-Octacontane 81 C.sub.81H.sub.164
n-Henoctacontane 82 C.sub.82H.sub.166 n-Dooctacontane 83
C.sub.83H.sub.168 n-Trioctacontane 84 C.sub.84H.sub.170
n-Tetraoctacontane 85 C.sub.85H.sub.172 n-Pentaoctacontane 86
C.sub.86H.sub.174 n-Hexaoctacontane 87 C.sub.87H.sub.176
n-Heptaoctacontane 88 C.sub.88H.sub.178 n-Octaoctacontane 89
C.sub.89H.sub.180 n-Nonaoctacontane 90 C.sub.90H.sub.182
n-Nonacontane 91 C.sub.91H.sub.184 n-Hennonacontane 92
C.sub.92H.sub.186 n-Dononacontane 93 C.sub.93H.sub.188
n-Trinonacontane 94 C.sub.94H.sub.190 n-Tetranonacontane 95
C.sub.95H.sub.192 n-Pentanonacontane 96 C.sub.96H.sub.194
n-Hexanonacontane 97 C.sub.97H.sub.196 n- Heptanonacontane 98
C.sub.98H.sub.198 n-Octanonacontane 99 C.sub.99H.sub.200
n-Nonanonacontane 100 C.sub.100H.sub.202 n-Hectane 101
C.sub.101H.sub.204 n-Henihectane 102 C.sub.102H.sub.206 n-Dohectane
103 C.sub.103H.sub.208 n-Trihectane 104 C.sub.104H.sub.210
n-Tetrahectane 105 C.sub.105H.sub.212 n-Pentahectane 106
C.sub.106H.sub.214 n-Hexahectane 107 C.sub.107H.sub.216
n-Heptahectane 108 C.sub.108H.sub.218 n-Octahectane 109
C.sub.109H.sub.220 n-Nonahectane 110 C.sub.110H.sub.222
n-Decahectane 111 C.sub.111H.sub.224 n-Undecahectane
II. Cyclic Compounds
[0065] Cyclic compounds can be categorized:
TABLE-US-00003 Alicyclic Compound An organic compound that is both
aliphatic Cycloalkane and cyclic with or without side chains
Cycloalkene attached. Typically include one or more all- carbon
rings (may be saturated or unsaturated), but NO aromatic character.
Aromatic hydrocarbon See above and below Polycyclic aromatic
hydrocarbon Heterocyclic compound Organic compounds with a ring
structure containing atoms in addition to carbon, such as nitrogen,
oxygen, sulfur, chloride as part of the ring. May be simple
aromatic rings or non-aromatic rings. Some examples are Pyridine
(C5H5N), Pyrimidine (C4H4N2) and Dioxane (C4H8O2). Macrocycle See
below.
III. Polycyclic Compounds--polycyclic compound is a cyclic compound
with more than one hydrocarbon loop or ring structures (Benzene
rings). The term generally includes all polycyclic aromatic
compounds, including the polycyclic aromatic hydrocarbons, the
heterocyclic aromatic compounds containing sulfur, nitrogen,
oxygen, or another non-carbon atoms, and substituted derivatives of
these. The following is a list of some known polycyclic
compounds.
TABLE-US-00004 Example Polycyclic Compounds Sub-Types Compounds
Bridged Compound -- Bicyclo compound adamantane compounds which
contain amantadine interlocking rings biperiden memantine
methenamine rimantadine Macrocyclic Compounds -- Calixarene any
molecule containing a Crown Compounds ring of seven, fifteen, or
any Cyclodextrins arbitrarily large number of Cycloparaffins atoms
Ethers, cyclic Lactams, macrocyclic Macrolides Peptides, cyclic
Tetrapyrroles Trichothecenes Polycyclic Hydrocarbons, Acenaphthenes
Aromatic Anthracenes Azulenes Benz(a)anthracenes Benzocycloheptenes
Fluorenes Indenes Naphthalenes Phenalenes Phenanthrenes Pyrenes
Spiro Compounds Steroids Androstanes Bile Acids and Salts
Bufanolides Cardanolides Cholanes Choestanes Cyclosteroids Estranes
Gonanes Homosteroids Hydroxysteroids Ketosteroids Norsteroids
Prenanes Secosteroids Spirostans Steroids, Brominated Steroids,
Chlorinated Steroids, Fluorinated Steroids, Heterocyclic
[0066] The addition of the side chains may increase the stability
and strength of the hydrophobic interaction between the Tail group
and hydrophobic cavity of the liposomes. This increase in strength
and stability may provide further advantages in the ability of the
hm-Chitosan film and functionalized film to self-assemble, such as
providing increased or stabilized rates of reaction in the
formation of the network film. The ability to adjust the side chain
hydrophobicity may directly impact upon various characteristics of
the complexed proteins contained within the films, such as the
tertiary and quaternary structures of the hm-Chitosan backbone,
either as a reactive, solid-state hm-Chitosan film matrix or as a
networked, functionalized film including bound liposomes.
[0067] As is generally known, vesicles are relatively small
membrane enclosed "sacs" that are able to store, transport, or
digest cellular products and waste (various cellular substances)
within an intracellular environment. While the overall size of
these "sacs" may vary it is known that they may range from
nano-scale sizes to larger sizes. Two standard types of vesicles
may be distinguished by their membrane layer. Where the enclosed
"sacs" of the vesicles are separated from an exterior environment,
such as a cytosolic environment, by a membrane composed of a
hydrophilic "head" region in contact with the surrounding
environment and sequestering the hydrophobic "tail" regions in the
center, they are commonly referred to as micelles. Where the
membrane of the vesicle is composed of at least one lipid bilayer
(unilamellar vesicles) that encloses or forms about an interior
cavity or intravesicular environment they are typically referred to
as liposomes. While it is common that the intraliposomal
(intravesicular) environment be a hydrophilic one, alternative
environments may be found or created within these interior cavities
of the vesicle or liposome.
[0068] Generally, the liposomes otherwise known as phospholipid
vesicles, are biocompatible nano-scale structures which have been
shown to have numerous applications as will be discussed. The
liposomes are generally spheroid structures and typically contain a
hydrophilic (water-filled) core or interliposomal cavity that is
capable of storing and/or transporting water soluble substances
within and an oily (hydrophobic) shell made up of hydrophobic
(water-fearing or repelling) substances which may store and/or
transport hydrophobically soluble compounds which may include
various bioactive agents or moieties and/or may include various
biomarkers for detection, as will be discussed. The various types
of agents, moieties, markers and/or otherwise may be included
within the membrane bi-layer and may interact across one or more of
the bi-layers without departing from the scope and spirit of the
present invention. The hydrophobic cavity exists between the "head"
groups of the surfactant molecules that form the bi-layer membrane
of the liposome. The size of these cavities may also vary from
nano-scale to larger sizes.
[0069] Vesicles and particularly liposome structures have been of
particular interest because of their ability to entrap desired
chemicals in their interior and thereafter release these chemicals
to the external environment in a controlled manner. Some of the
various types of substances contained within the various cavities
have been known to provide functional components that may range in
operation and application from therapeutics
(pharmaceuticals/biologics/medicines), to drug delivery and
controlled release, to bioseparations and sensing, to cosmetics, to
herbicides, pesticides or other agricultural applications, to
nutraceutical, to pain relief, to various structural applications.
The size of these constructed compounds may also vary from
nano-scale to larger than nano-scale sizes and be contained within
the cavities vesicle or liposome.
[0070] The functionality of the chitosan scaffold may be
significantly enhanced by first packaging various bioactive
agents/reactive agents into the vesicles (liposomes), and
subsequently anchoring them to the chitosan scaffold. Generally,
and as will be described as the formation processes herein below,
this enhanced functionality may be achieved by either passing a
solution of vesicles over a dry chitosan film, or by detaching the
chitosan scaffold from a surface substrate and subsequently dipping
it into a vesicle solution. The resulting functionalized
biopolymeric networked film or functionalized film, may be capable
of such activity as delivering drugs or bioactive proteins, such as
platelet-derived growth factor (PDGF), epidermal growth factor
(EGF) and basic fibroblast growth factor (bFGF) to significantly
accelerate the regeneration of damaged tissue, as well as vascular
endothelial growth factor (VEGF) to promote growth of new blood
vessels within the new tissue. Furthermore, by tailoring vesicle
(liposome) composition, the release time and dose of drugs,
proteins or other bioactive agents administered to the wounds or
other appropriate environments can be controlled. In addition,
since chitosan is an amino polysaccharide, different chemicals
(e.g., anchoring molecules, such as the RGD peptides) can be
chemically attached to the scaffold. Again, it is this "readily
reactive" characteristic of chitosan that is often lacking in other
biopolymers and allows the current invention to be tailored to
address the needs of various, numerous, and particular types of
applications.
[0071] As previously identified, liposomes are generally, spherical
vesicles with at least one lipid bilayer membrane typically
composed of phospholipids (lipids containing phosphate) and
cholesterol (steroidal derivative polymer). It is common for
liposome composition to include naturally-derived phospholipids
with mixed lipid chains or pure surfactant components like
dioleoylphosphatidylethanolamine (DOPE). Surfactants are
amphiphilic (hydrophilic and hydrophobic) compounds or wetting
agents that lower the surface tension of a liquid or the
interfacial tension between two liquids. Thus, the bilayer
membrane(s) of liposomes (vesicles) are composed of surfactant
(amphiphilic) compounds that form about or around the
intraliposomal environment (aqueous, hydrophilic, or otherwise)
contained and enclosed within the liposome.
[0072] As previously mentioned, it is known to have multi-layered
liposomes (vesicles) which are actually liposomes within liposomes
or vesicles.
(See, Jae-Ho Lee, Vivek Agarwal, Arijit Bose, Gregory F. Payne, and
Srinivasa R. Raghavan, Transition from Unilamellar to Bilamellar
Vesicles Indusced by an Amphiphilic Biopolymer, APS, Physical
Review Letters 2006, 96, 048102-1-4, which is herein incorporated
by reference in its entirety.)
[0073] These multilamellar structures may be of various sizes and
numbers of structural components and may include no or various
biologically/pharmacologically active agents, ingredients,
moieties, reactive elements, and the like as contemplated by those
skilled in the art. These bioactive agents typically come in the
form of functional groups or moieties, as discussed previously. For
instance, the overall size of the liposome as defined by the outer
bi-layer may range from below to above 100 nanometers while one or
more secondary liposomal structures such as an inner bi-layer,
which may be contained within the outer bi-layer of the liposomal
structure, may range from below to above 100 nanometers.
Multilamellar structures may include one or more secondary
liposomal structure(s) or inner bi-layers contained within the
outer bi-layer liposomal structure.
[0074] The bioactive agents contained within either or both the
outer bi-layer and/or inner bi-layer may be homologous or
heterologous with one another and capable of providing various
desired functional characteristics. The scope of the bioactive
capabilities of the liposomal or vesicular structures is only
limited by the needs of the creator of the structure. Thus, the
current invention may find practical application across various
technology, industrial, medicinal, cosmetic, agricultural and other
fields as have been identified and those other fields that may be
contemplated by those of ordinary skill in various fields of
art.
[0075] As discussed and shown throughout the drawing figures, the
liposomes of the preferred embodiments of the current invention are
attached to the hm-Chitosan film matrix through hydrophobic
interaction. As shown in FIGS. 3 and 4, the hydrophobic interaction
between the hm-Chitosan and the liposomes occurs via the "insertion
and anchoring" of the hydrophobic Tail group of the amphiphilic
compound into the lipid (i.e., phospholipid) bi-layer membrane of
the liposome. The insertion process is driven by the generally
understood hydrophobic interaction and those forces that are at
work which tend to group like molecules when they exist in a
heterogenous environment. Thus, the hydrophobic effect or
interaction is evidenced by the tendency of hydrophobic components
to group together versus interacting or bonding with other
molecules.
[0076] The anchoring of the hydrophobic molecules is also a result
of the hydrophobic interaction and these hydrophobic molecules will
tend to stay grouped together as they form multiple bonds between
different parts of the same molecule or between different
molecules. Using these hydrophobic interactions the liposomes are
anchored to the hm-Chitosan matrix by means of self-assembly. The
self-assembly method for formation of the current invention's
biopolymeric networked film is a thermodynamically driven process
requiring little energy to drive the reaction/bonding process and
resulting in complexed molecules with reduced energy states.
[0077] The liposomes, as shown in FIG. 3 and as may be seen
throughout the other drawing figures of the instant application,
act as physical cross-links between the numerous hm-Chitosan
scaffolds within the biopolymeric networked film. As used herein,
"cross-links", "cross-linkers" or "cross-linking" are descriptive
of the use of molecules to form bonds that link one polymer chain
to another and are typically employed to promote a difference in
the polymer's physical properties. Numerous and varied
cross-linkers are typically used to analyze subunit structure of
proteins, protein interactions, and various parameters of protein
function.
[0078] In a preferred embodiment of the current invention, the
employing of liposomes or vesicle structures for cross-linking the
hm-Chitosan scaffolds provided the 3-dimensional network from which
the biomaterial compositions of matter, specifically the
solid-state, dry hm-Chitosan and functionalized films of the
current invention were formed. (See, Jae-Ho Lee, John P. Gustin,
Tianhong Chen, Gregory F. Payne, and Srinivasa R. Raghavan,
Vesicle--Biopolymer Gels: Networks of Surfactant Vesicles Connected
by Associating Biopolymers, ACS, Langmuir 2005, 21, 26-33; and Chao
Zhu, Jae-Ho Lee, Srinivasa R. Raghavan, and Gregory F. Payne,
Bioinspired Vesicle Restraint and Mobilization Using a Biopolymer
Scaffold, ACS, Langmuir 2006, 22, 2951-2955, both publications are
herein incorporated by reference in their entireties.)
[0079] As stated previously, the Liposomes may be loaded with
various bioactive/chemically reactive agents. When the liposomes
are so formed they may be commonly referred to as "functionalized"
and thus, when these functionalized liposomes are attached, via
hydrophobic interaction(s), to the novel, solid-state hm-Chitosan
film matrix then a preferred embodiment of the current invention is
a functionalized biopolymeric networked film or functionalized
film, as stated previously.
[0080] A preferred embodiment of a formation process of the
functionalized film of the current invention is shown in FIG. 6
(PHASE II). In this process the novel, solid-state, dry hm-Chitosan
film matrix is interacted with a vesicle solution which is dropped
onto the film and allowed to soak for a specified period of time.
That period of time may range from seconds, to minutes, to hours,
to days, depending on the reaction conditions, composition of the
vesicle (liposome) solution, condition of the hm-Chitosan film, and
various other factors as contemplated by those skilled in the art.
After soaking has been allowed for the specified period of time,
the film is rinsed off with a buffer solution to remove any excess
and unbound liposomes. The binding of the vesicles is via the
hydrophobic interaction and the bonds that are formed are
non-covalent. This is a significant advantage over the prior art,
which typically "mixed" the vesicle and polymer and did not utilize
hydrophobic interactions as is used by the current invention, in
that the non-covalent bonds are formed through a self-assembly
process that is thermodynamically driven and therefore requires
less energy and promotes the formation of more stable, lower energy
states for the complexed molecules.
[0081] A novel method for formation or fabrication of the
functionalized film of the current invention is shown in FIG. 13.
In this formation process the first step 1305 is to select or
obtain a solid-state, dried hm-Chitosan film matrix in accordance
with the composition of matter described previously in the instant
specification. Then in step 1310, a vesicle solution is dropped
onto the film. The process may also include a step of specifying a
period of time for which the vesicle solution may be allowed to
soak onto the hm-Chitosan film matrix. Then in step 1315, the
soaking vesicle solution is rinsed off the hm-Chitosan film matrix
using some type of buffer solution. Upon completion of the rinsing
step, step 1320 is a dehydrating process, wherein the complexed,
film including liposomes bound to the hm-Chitosan scaffold matrix
is allowed to dry. The final composition of matter obtained from
this process is a solid-state, dry functionalized film.
[0082] By way of example and without intending to limit the scope
and spirit of the present invention, the following are two
alternative, exemplary approaches to the fabrication of the current
invention. In the first fabrication process, the first step is to
dissolve hydrophobically-modified chitosan in an aqueous acidic
solution such as 0.2 M acetic acid, lactic acid or formic acid.
Optimal concentrations of hm-chitosan in these initial solutions
are 0.5 to 1.5 (w/v) %. Once the hm-chitosan is completely
dissolved in solution, the resulting liquid is cast into a film by
pouring it onto a glass plate followed by drying in a vacuum oven
for 48 h at 37.degree. C. After drying, the film can be peeled off
the glass surface and stored in an air-tight container at ambient
conditions for further and/or later use.
[0083] Another method of drying the liquid hm-chitosan solution is
lyophilization. In this case the liquid cast onto the glass plate
can be frozen by placing it at -20.degree. C. for 2 hours. The
resulting frozen film can be placed in a freeze-drying chamber
under high vacuum for 24 hours. Once all solvent is removed from
the biopolymer, the `sponge-like` film can again be carefully
peeled off of the glass and stored for further use.
[0084] The difference between the two methods of drying as it
relates to the film properties is that the biopolymer chains have
much less space between each other after drying in a vacuum oven.
In the case of lyophilized films, the biopolymer chains cannot
rearrange themselves as water molecules are being removed from the
system. Hence the lyophilized films have a much higher degree of
flexibility, but yet a significantly lower degree of tensile
strength as compared to the vacuum-oven-dried films. Also, the
vacuum-oven-dried films are transparent, whereas the lyophilized
films are opaque.
[0085] As shown in FIGS. 7 and 8 differences in the processes
through which the vesicle or liposomes are interacted with the
hm-Chitosan film matrix are contemplated. FIG. 7 shows that the
vesicle solution is passed over the hm-Chitosan film and allowed to
dry, without the rinsing with a buffer step. FIG. 8 shows that the
process can be achieved with both the vesicle/liposomes and
hm-Chitosan components in a solution state which is then mixed and
dried to form the functionalized film. As previously stated, in a
further alternative, preferred embodiment, the chitosan scaffold
may be detached from the surface substrate upon which it was cast
(e.g., glass) to form the film and then it may be subsequently
dipped or immersed into a vesicle solution. The length of time or
number of times this "dipping" or "immersion" process occurs may be
varied as contemplated by those of skill in the art.
[0086] A practical application of the current functionalized film,
as shown in FIGS. 7 and 11, and as represented in FIG. 9, is in the
arena of wound dressings for the healing of wounds, chronic or
otherwise. Each year 71 million people around the world physically
experience the pain and horror of hospitalization due to serious
wound or burn injuries. The 39 million suffering from chronic
wounds (e.g. diabetic ulcers, venous ulcers and pressure sores) and
burns unfortunately must also bear the financial strain of an
estimated $3000-$5000 per day in inpatient care during recovery
periods of up to 20 weeks. The guiding vision for this project
stems from the motivation to vastly improve the lives of such
chronic wound and burn patients, both in their medical treatment
and in their finances. Conventional treatments of patients with
non-healing wounds include extended stays within hyperbaric oxygen
chambers as well as daily cleaning and disinfection of the damaged
tissue between wound dressing changes. Biomedical engineers seeking
to improve this dismal regimen of therapy have exploited the
crucial role of growth factors in accelerating wound healing; this
has already led to the development and regulatory approval of one
topically applied platelet-derived growth factor (PDGF), the active
component of the commercially available Regranex.TM. Gel. Although
this gel represents an advancement in wound treatment, it has not
achieved clinical results that outpace its cost (.about.$300 per
daily dose). Also, Regranex.TM. Gel does not inherently prevent
infection, nor does it control moisture and oxygen transfer to the
wound, both of which are essential for proper wound healing.
[0087] The currently and commonly available wound dressings may be
categorized into two major groups: (1) chitosan dressings (Hemcon,
Chitoskin) and (2) all other dressings including foam, film,
hydrocolloid and alginate dressings (CarePro, Inc., Brennan and
Integra Lifesciences, Corp.). The advantages of chitosan use as
wound dressing are that chitosan and its derivatives have been
found to promote fibroblast growth and affect macrophage activity,
both of which accelerate the wound healing process; Chitosan
derivatives also exhibit good homeostatic properties as well as
broad spectrum antimicrobial capabilities, for example, chitosan
acetate has been shown to be superior to both currently available
alginate bandages and silver sulfadiazine in killoing bacterial. As
a result, a commercial wound dressing product made of chitosan (The
HemCon.RTM. Bandage) appeared in the market in 2004 and is
currently employed in treating wounds suffered by American soldiers
in both Iraq and Afghanistan.
[0088] However, both types of wound dressing have their limited
abilities to cover multiple types of wounds or different stages of
treatment. For example, currently all HemCon products are for the
sole purpose of stopping hemorrhage. The usefulness of such
products is limited to the first stage of severe wound treatment
and is not favorable for use on burn injuries. In the preferred
embodiments of the current invention, which incorporates the
enhanced functionality and controlled release, the functionalized
biopolymeric networked film may promote increased healing
performance during the initial stages of wound and burn injury but
also may provide increased wound healing performance during the
later and more critical stages of recovery, such as tissue
regeneration. Also, the current invention may promote significantly
more useful treatment of wounds in patients with compromised
healing ability, such as is found with the elderly, the very young,
and diabetics.
[0089] Therefore, a continued need exists for multi-functional
biomaterials that are able to accelerate the healing of damaged
tissue, prevent microbial infection, and maintain adequate transfer
of oxygen and moisture, all while keeping treatment costs at a
commercially feasible level. In a preferred embodiment of the
current invention, the functionalized film is incorporated into
bandages for chronic wound and burn patients that aim to fill these
largely unmet clinical needs. The functionalized film has packaged
protein growth factors into lipid nano-containers ("liposomes") and
subsequently anchored these containers to the biopolymeric film
matrix by means of a self-assembly process. The beauty of the
self-assembly method for fabrication is that the process is
thermodynamically driven. The resulting bandage may promote the
ease with which various bioactive proteins are incorporated and
delivered to damaged tissue at a controlled and biologically
relevant rate. The novel functionalized film of the current
invention, the formation of which is driven by hydrophobic
interactions, may assist in providing several advantages over
traditional products due to one or more of the following noted
characteristic features of the functionalized film: 1)
incorporation of multiple healing functions within one device; 2)
optimization of the healing process by providing a platform from
which to deliver a wide range of therapeutic agents at a specific
rate dictated by specific patient needs; 3) freedom from costly
requirements for sophisticated device production techniques; 4)
packaging of protein therapeutics within liposomal nano-containers,
which allows for retention of molecular bioactivity during storage;
5) usage of the device matrix material, chitosan, a cheap and
biocompatible material that demonstrates optimal characteristics
for wound healing due to its excellent hemostatic (ability to stop
bleeding) and anti-microbial properties.
[0090] The acceleration of chronic wound healing by sustained
release of growth factors into wounded tissue has been studied for
over 20 years, but is still not thoroughly understood. When growth
factors are delivered as a bolus (e.g. administration of
Regranex.TM. Gel), rapid clearance from the wound site occurs,
making it difficult to maintain therapeutic concentrations over
prolonged periods of time. Bolus administration thus necessitates
large amounts of growth factors that may have dangerous side
effects, such as vascularization of non-target tissues. For growth
factors to promote wound healing, they should therefore be
delivered in a sustained manner. The use of a sustained release
vehicle, such as the novel polymer matrix of the current invention,
to deliver the growth factors ensures an increased cell response
while minimizing the total dose required.
[0091] In addition to the release kinetics, the stability of growth
factors is equally crucial for eliciting cell responses. Polymer
matrices have been widely used as depots for sustained drug
delivery. However, in contrast to synthetic, low molecular weight
drugs, proteins have limited chemical and physical stability which
becomes evident in their susceptibility to proteolysis, chemical
modification and denaturation, even within a polymer matrix
environment. The solution provided by the current invention to the
stability issue is "encapsulation" within liposomes. The
attractiveness of liposomes as protein delivery systems can be
assigned to the fact that the encapsulated proteins may remain in
their preferred aqueous environment within the vesicles while the
liposomal membrane protects them against proteolysis and other
destabilizing factors. However, the liposomes themselves are
unstable in biological environments and are rapidly uptaken by
macrophages of the reticuloendothelial system in vivo.
[0092] The value of combining the advantages of polymers and
liposomes for wound healing by embedding protein-containing
liposomes within a fibrin mesh has been previously validated by
various studies. In one particular study, the release rate of the
protein (horseradish peroxidase, HRP) was entirely dictated by the
degradation rate of the fibrin, and the activity of the HRP was
largely retained upon release. However, these studies have not
addressed the novel compositions of matter, systems, kits and
fabrication processes, utilized by the current invention which is
employing a novel liposome-embedded polymer matrix, wherein in the
preferred embodiments, the matrix consists of a inexpensive
biodegradable material, chitosan. By mixing a
hydrophobically-modified (hm)-chitosan (C.sub.12-hydrophobes
covalently attached to the hydrophilic backbone) in solution with
liposomes and then casting it into a film, an elastic composition
of matter or medical device is formed by the current invention.
FIGS. 7 and 11 illustrate such a flexible, elastic wound healing
medical device.
[0093] In a preferred embodiment, the film results from mixing
solutions of 0.5 wt % hm-chitosan and 1.2 wt % liposomes and then
drying the complexed solution in a vacuum. It is known that
individual solutions of hm-chitosan and liposomes at the same
respective concentrations are both thin fluids of low viscosity.
However, their mixture forms an elastic composition of matter due
to the insertion of hydrophobes from the polymer backbone into the
hydrophobic bilayers of the liposomes, resulting in a 3-dimensional
network in which the liposomes act as physical cross-links.
[0094] The current invention, utilizes this novel, solid-state
hm-Chitosan film, which has physical attributes suitable for
dressing a wound (flexibility, adhesiveness, transparency for
monitoring). Then via fabrication steps and processes, the film has
growth factor-containing liposomes attached, for example, simply by
soaking the film in a solution of liposomes. FIG. 7 shows a
schematic of the fabrication process for creating such an
Inn-chitosan/liposome wound dressing by self-assembly. Note that
the anchoring of liposomes occurs simply by hydrophobic,
non-covalent interactions between the hydrophobes and the liposomal
bi-layers.
[0095] The hm-Chitosan film anchors liposomes by means of simple,
non-covalent interactions. Results of the novel films capabilities
with regards to anchoring liposomes are shown below in Schematic 1.
The novel functionalized film material was made simply by soaking
an hm-Chitosan film in a solution of fluorescently-tagged liposomes
at physiological pH. The fluorescence microscopy images clearly
show bright fluorescence from the hm-Chitosan film, indicating that
a large number of liposomes are anchored. In comparison, liposome
anchoring (and thereby, fluorescence) is negligible for the
unmodified chitosan controls. Also, this spontaneous anchoring of
the liposomes onto hm-Chitosan may be a time-dependent process, as
the fluorescence intensity appears to have increased significantly
during the 20 minute interval. Thus, these results demonstrate that
hm-chitosan films can be therapeutically functionalized with
liposomes for biomedical applications. The ease of this fabrication
process may provide cost and time advantages and it should be
readily apparent to those skilled in the art that this novel
formation process allows the current invention to be utilized in a
broad range of fields of application.
[0096] In an alternative, preferred embodiment of the current
invention, a functionalized film is employed as part of an
implantable material or is formulated for drug delivery. The
scaffolds are biocompatible and biodegradable, thus, they may be
loaded with drugs either inside the bulk matrix or within the
liposomes themselves. This may allow for the possibility of having
two or more drugs, or other bioactive agents, loaded within the
device employing the functional film, and the device may have two
or more distinct sets, of release kinetics as a result. Also, the
matrix of the functionalized film will swell upon the transition
from physiological pH 7.4, to lower pH values of 6 or below, as
often observed in cancerous tissue. Therefore, the matrix may act
as a "smart" biomaterial which may promote the release drugs) or
other bioactive agent(s) with increased speed or expediency in
response to a drop in pH. Capsules may be formed from the film
through various processes known to those skilled in the art and/or
by dropping a mixture of liposomes and hm-Chitosan into a solution
of negatively charged surfactant or biopolymer. These
container-within-container structures may similarly be used as
multiple drug/bioactive agent release devices in addition to
providing targeted release by conjugating moieties such as
antibodies or RGD peptides to the surface of the capsule. The types
of antibodies or other "ligand" structures that may be conjugated
with the current invention may vary as contemplated by those of
skill in the art, wherein the conjugative process is commonly known
and easily performed, such that the reactivity of the free amine
groups which are present on the capsule surface may be
utilized.
[0097] The delivery mechanisms employed by the current invention
may vary significantly. Delivery of the functionalized biopolymer
may preferably occur through ingestion, formulated as a capsule. It
is contemplated that the functionalized biopolymer compound may be
formulated as an aqueous solution, such as a liquid drink, and
allow for oral ingestion. Further, the functionalized biopolymer
compound may be formulated as an organic compound including all
solid oral formulations, such as granules, a tablet, a capsule, and
the like, for ingestion. Alternatively, a food supplement, such as
a sports bar, nutraceutical, and the like, may be employed for
delivery of the functionalized biopolymer compound.
[0098] The solid oral formulation, and other dosage forms as
described herein, of the functionalized biopolymer compound may
further include various controlled release formulations, as
discussed previously. This may enhance its capabilities by enabling
a "response" over a prolonged period of time. Thus, the
functionalized biopolymer compound may be useful during activities
(i.e., athletic events) which may initiate the inflammatory
response in cells.
[0099] Other formulations, such as an emulsion, suspension, and the
like, may be employed and allow delivery of the present invention
to a desired location. The formulations may allow application
through a variety of methods, such as a topical application,
parenteral application, and the like. For example, topical
functionalized biopolymer compounds may include lotions, creams,
gels, and the like, and may be applied directly to a wounded or
inflamed area. These organic compounds may further comprise
penetrating agents, which may be employed to increase the
bio-availability of the bioactive agent across a membrane,
enhancing the topical functionalized biopolymer compound
lipophilicity. Parenteral methods of delivering the functionalized
biopolymer compound may include injections (subcutaneous or
intravenous), suppositories (rectal or vaginal), and the like.
Injections may comprise sterile solutions containing the
functionalized biopolymer compound and may be delivered directly to
the bloodstream or deposited in the inflamed tissue itself. The
suppositories may contain suspensions, solids, or liquid
formulations of the functionalized biopolymer.
[0100] For the delivery of drugs, the route of administration is
dependent on the dosage form of a given drug. Thus, various dosage
forms are known and contemplated for use by the current invention.
For example, (1) Inhaled dosage forms: Aerosol, Gas, Inhaler &
Metered dose inhaler, Solution for nebulizer; (2) Ophthalmic dosage
forms: Eye drop (solution or suspension), Ophthalmic gel,
Ophthalmic ointment; (3) Oral dosage forms: Capsule, Powerder,
Solution, Suspension, Tablet, Buccal or sublingual tablet; (4) Otic
dosage forms: Ear drop (solution or suspension); (5) Parenteral
dosage form: Solution or suspension for injection; (6) Rectal
dosage form: Enema, Suppository; (7) Topical dosage forms: Creams,
Gel, Liniment, Lotion, Ointment, Paste, Transdermal Patch; (8)
Vaginal dosage forms: Douche, Intrauterine device, Pessary (vaginal
suppository), Vaginal ring, Vaginal tablet. There are also various
types of Pharmaceutical forms which cover the way drugs are
delivered to a patient and include, Ampules, Capsules, Creams,
Elixirs, Emulsions, Fluids, Grains, Drops, Injections, Solutions,
Lotions, Sprays, Powders, Suspensions, Syrups, Tablets, Tinctures,
and Ointments. While some of these forms may be repetitive it is
important to note that all the various dosage forms and delivery
mechanisms are contemplated for use by the current invention.
[0101] As discussed previously, the functionalized biopolymeric
matrix of the current invention may be employed to deliver
bioactive agents, including bioactive proteins, such as
platelet-derived growth factor (PDGF), epidermal growth factor
(EGF) and basic fibroblast growth factor (bFGF) that may
significantly accelerate the regeneration of damaged tissue, as
well as vascular endothelial growth factor (VEGF) to promote growth
of new blood vessels within the new tissue. These bioactive agents
may be delivered by the current invention either alone or in
combination with various other factors, drugs, biologics, cosmetics
and otherwise. The mechanisms employed for delivery may be any of
those previously discussed or alternative methods as contemplated
by those skilled in the art.
[0102] In a still further preferred embodiment, the current
invention may be employed for the detection of bacteria, viruses
and other dangerous substances in various environments, such as
hospitals, airplanes, and other commonly contaminated places. This
sensing application may be realized by incorporating a
functionalized film of the current invention into various devices,
such as napkins, wet wipes, paper towels and the like as may be
contemplated. Their use may be as simple as wiping any one of the
various products incorporating the technology of the current
invention across a surface. In a particularly preferred embodiment,
antibodies may be loaded to the liposomes surface and chemicals are
loaded either inside of the liposomes, onto the liposome surface,
or, in the case of polydiacetlyene vesicles, the vesicle
substituents themselves. The liposomes are anchored to the surface
of the hm-Chitosan matrix, which makes the functional liposomes
accessible by the contaminants. When the antibodies attach to their
target they may trigger the chemical signal by changing color or
through another detection/indication affect. Where biohazards are
detected by the product of the current invention, the surface may
be disinfected and retested with another "wipe" to insure no
further contaminates exist.
[0103] The current invention further provides two novel systems. In
a first system, the hm-Chitosan film matrix is presented for use.
The use of this scaffold structure may be to functionalize it by
loading vesicles whether or not including bioactive agents. The
second exemplary, preferred embodiment of a system of the current
invention may include the functionalized biopolymeric networked
film being presented for use, such as within the fibrin mesh of a
bandage or patch, in various environments as contemplated by those
of ordinary skill in the art.
[0104] It is to be understood that the bioactive agents of the
vesicles, for all of the exemplary, preferred embodiments described
and those that are contemplated, may be any type of bioactive agent
as contemplated. For instance, the agent may be various
medications. Medications could be for: (1) the gastrointestinal
tract or digestive system, (2) the cardiovascular system, (3) the
central nervous system, (4) pain & consciousness (analgesic
drugs), (5) musculo-skeletal disorders, (6) the eye, (7), the ear,
nose and oropharynx, (8) the respiratory systems, (9) endocrine
problems, (10) the reproductive system or urinary system, (11)
contraception, (12) obstetrics and gynecology, (13) the skin, (14)
infections and infestations, (15) immunology, (16) allergic
disorders, (17) nutrition, (18) neoplastic disorders, (19)
diagnostics, (20) euthanasia.
[0105] In the diagnosis arena, similar to the detection of bacteria
and viruses, the current invention may employ various constructs
such as antibodies to provide diagnostic capabilities. Various
different types of therapies may be promoted through the use of the
current invention, such as hormone therapy whether amine-derived,
peptide(s), and/or lipid and phospholipid-derived.
[0106] Still further, the current invention may be employed to
store and deliver various proteins, such as enzymes which may
include any of the (1) Oxidoreductases: catalyze
oxidation/reduction reactions, (2) Transferases: transfer a
function group (e.g., a methyl or phosphate group), (3) Hydrolases:
catalyze the hydrolysis of various bonds, (4) Lyases: cleave
various bonds by means other than hydrolysis and oxidation, (5)
Isomerases: catalyze isomerization changes within a single
molecule, or (6) Ligases: join two molecules with covalent
bonds.
[0107] In the agricultural and/or botanical fields, the current
invention may be employed for the delivery of various agents for
various products, including insecticides, fertilizer, and the like.
Insecticides may vary from agricultural (e.g., organochlorides,
organophosphates, pyrethroids, biological insecticides) to
individual insecticides (e.g., chlorinated hydrocarbons,
organophosphorus, carbamates, phenothizine, pyrethroids, plant
toxin derived). The current invention may be employed for use with
various herbicides (organic or inorganic) which may be classified
either by activity (e.g., Contact or Systemic), use (e.g.,
Soil-applied, Pre-plant incorporated, Preemergent herbicides,
Post-emergent herbicides), or mechanism of action (e.g., ACCase
inhibitors, ALS inhibitors, EPSPS inhibitors, Synthetic auxin,
Photosystem II inhibitors). Another field of application of the
current invention may be Fertilizers and/or Manure whether they are
classified as organic or inorganic fertilizers or green manures or
animal manures.
[0108] The current invention also provides a preferred embodiment,
wherein the novel hm-Chitosan and/or functionalized film may be
deployed in a kit. For example, the kit may be a
detection/diagnostic kit and include a collection of "wipes"
(described previously) and an instruction manual for the proper use
of the wipes for the determination of whether or not a contaminate,
disease, virus, or otherwise is present. Various other types of
products employing the technology of the current invention may be
included within a kit as is contemplated by those of ordinary skill
in the art. For example, a diagnostic kit may include a solution
containing various antibodies to antigens presented by certain
diseases or viruses. By collecting a sample and placing it in
contact with the solution of the kit, and preferably in accordance
with an instruction manual provided with the kit, a user may be
able to detect or identify the presence of a disease or virus.
Other examples of kits, such as prognostic indicator kits, assaying
kits, and the like, employing the novel invention of the instant
application are contemplated and fall within the scope and spirit
of the present invention.
[0109] In the exemplary embodiments, it is understood that the
specific order or hierarchy of steps in the methods disclosed are
examples of exemplary approaches. Based upon preferences, it is
understood that the specific order or hierarchy of steps in the
method can be rearranged while remaining within the scope and
spirit of the present invention. The accompanying method claims
present elements of the various steps in a sample order, and are
not necessarily meant to be limited to the specific order or
hierarchy presented.
[0110] It is to be understood that the functional capabilities of
the current invention, including those provided within the methods
described, may be implemented in various manners. It is
contemplated that various functional features may be individually
provided to the system of the present invention. Further, the
specific order or hierarchy of functional capabilities described
herein are merely exemplary approaches and based upon design
preferences may be rearranged while remaining with the scope and
spirit of the present invention. The methods may employ the above
described functional capabilities in various ways, enabling one or
many of the features without regard to any specific hierarchical
order.
[0111] It is believed that the present invention and many of its
attendant advantages will be understood by the forgoing
description. It is also believed that it will be apparent that
various changes may be made in the form, construction and
arrangement of the components thereof without departing from the
scope and spirit of the invention or without sacrificing all of its
material advantages. The form herein before described being merely
an explanatory embodiment thereof. It is the intention of the
following claims to encompass and include such changes.
* * * * *