U.S. patent application number 16/571402 was filed with the patent office on 2020-03-12 for antifungal compositions and methods of use thereof.
The applicant listed for this patent is North Carolina Agricultural and Technical State University, The University of North Carolina at Greensboro. Invention is credited to Dennis R. LaJeunesse, Nafisa Sirelkhatim, Lifeng Zhang.
Application Number | 20200077652 16/571402 |
Document ID | / |
Family ID | 58720094 |
Filed Date | 2020-03-12 |
United States Patent
Application |
20200077652 |
Kind Code |
A1 |
Zhang; Lifeng ; et
al. |
March 12, 2020 |
ANTIFUNGAL COMPOSITIONS AND METHODS OF USE THEREOF
Abstract
The presently disclosed subject matter relates generally to
antifungal nanofibrous materials and the use of such materials.
Inventors: |
Zhang; Lifeng; (Oak Ridge,
NC) ; LaJeunesse; Dennis R.; (Greensboro, NC)
; Sirelkhatim; Nafisa; (Greensboro, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
North Carolina Agricultural and Technical State University
The University of North Carolina at Greensboro |
Greensboro
Greensboro |
NC
NC |
US
US |
|
|
Family ID: |
58720094 |
Appl. No.: |
16/571402 |
Filed: |
September 16, 2019 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15360068 |
Nov 23, 2016 |
10412962 |
|
|
16571402 |
|
|
|
|
62259900 |
Nov 25, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08L 1/12 20130101; C09D
101/12 20130101; C08L 33/20 20130101; A01N 43/16 20130101; C08K
7/02 20130101; C09D 7/70 20180101; C09D 7/65 20180101; A01N 37/34
20130101; C09D 5/1637 20130101; A01N 43/16 20130101; A01N 25/14
20130101; A01N 25/34 20130101; A01N 37/34 20130101; A01N 25/10
20130101; A01N 25/14 20130101; A01N 25/34 20130101 |
International
Class: |
A01N 43/16 20060101
A01N043/16; A01N 37/34 20060101 A01N037/34; C09D 101/12 20060101
C09D101/12; C09D 5/16 20060101 C09D005/16; C09D 7/40 20060101
C09D007/40 |
Claims
1. A method for the antifungal treatment of a surface comprising:
(a) providing a surface exposed to a fungus or contaminated with a
fungus; and (b) applying a composition comprising an antifungal
effective amount of nanofibers of cellulose acetate to the surface,
wherein the antifungal effective amount is an amount sufficient to
inhibit growth of the fungus on the surface.
2. The method of claim 1, wherein the antifungal effective amount
is an amount selected from the group consisting of an amount
sufficient to reduce optical density at 600 nanometers (OD.sub.600)
of a solution of the fungus exposed to the nanofibers of cellulose
acetate of the composition to less than about 75% of the OD.sub.600
of a solution of the fungus not exposed to the nanofibers of
cellulose acetate of the composition, an amount sufficient to
reduce a normalized Colony Forming Unit ratio (CFU) of the fungus
exposed to the nanofibers of cellulose acetate of the composition
to no more than about 60% of the CFU of the fungus not exposed to
the nanofibers of cellulose acetate of the composition, and an
amount sufficient to reduce MTT absorbance of a solution of the
fungus exposed to the nanofibers of cellulose acetate of the
composition to less than about 50% of the MTT absorbance of a
solution of the fungus not exposed to the nanofibers of cellulose
acetate of the composition.
3. The method of claim 1, wherein the nanofibers of cellulose
acetate are the only components of the composition that have the
antifungal activity.
4. The method of claim 1, wherein the antifungal treatment
comprises inhibiting or preventing fungal growth on the
surface.
5. The method of claim 4, wherein the nanofibers are electrospun
cellulose acetate nanofibers.
6. The method of claim 1, herein the surface is porous,
semi-porous, or non-porous.
7. The method of claim 1, wherein the surface is metal, wall board,
ceiling tile, paper, textile, concrete, stone, brick, wood,
plastic, ceramic, or leather.
8. The method of claim 7, wherein the nanofibers are electrospun
cellulose acetate nanofibers.
9. The method of claim 1, wherein the surface is a textile.
10. The method of claim 9, wherein the nanofibers are electrospun
cellulose acetate nanofibers.
11. The method of claim 1, wherein the surface is a garment,
bedding, or a part of a shoe.
12. The method of claim 11, wherein the surface is a fibrous
material and the nanofibers are electrospun cellulose acetate
nanofibers.
13. The method of claim 1, wherein the fungus is Saccharomyces
cerevisiae and/or Candida albicans.
14. The method of claim 1, the nanofibers of cellulose acetate have
an average diameter of between about 100 nm and 1000 nm, optionally
between about 300 nm and about 700 nm, further optionally between
about 400 nm and about 600 nm.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 15/360,068, filed Nov. 23, 2016, which claims priority
pursuant to 35 U.S.C. .sctn. 119(e) to U.S. Provisional Patent
Application Ser. No. 62/259,900, filed on Nov. 25, 2015, which is
hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The presently disclosed subject matter relates generally to
antifungal materials comprising nanofibers, such as
polyacrylonitrile nanofibers and/or cellulose acetate nanofibers,
and the use of such materials.
BACKGROUND
[0003] Fungi are abundant in the world and play a major role in
decomposing organic matter. While some fungi species are valuable,
e.g. Saccharomyces cerevisiae (S. cerevisiae) which is widely used
in fermentation, many species of fungi including molds and mildews
can spoil and/or damage indoor and outdoor surfaces. Many fungi
produce allergens and toxins that can harm humans, animals and
plants. Candida albicans (C. albicans) can lead to infection,
candidiasis (e.g. thrush, yeast infections, and onychomycosis), in
humans. The Centers for Disease Control and Prevention has reported
that Candida is the "most common cause of healthcare-associated
bloodstream infections in the United States"
(cdc.gov/fungal/antifungal-resistance.html, citing to Magill, S.
S., Edwards J. R., Bamberg, W., et al. "Multistate point-prevalence
survey of health care-associated infections." The New England
Journal of Medicine 2014; 370:1198-208). Uncontrolled fungal growth
is both an environmental concern and a health concern. In
particular, it is important to address the potential growth and
transfer of fungi in textiles, such as those found in hospitals,
hotels, offices, homes, retirement communities, and military
settings.
[0004] To fight fungi, a variety of antifungal reagents have been
developed, however most are non-specific. A number of chemical
agents have been shown to have antifungal activity, but can be
detrimental to the environment--toxic to plants, animals and
humans. Additionally, use of antifungal drugs may take long time
and side-effects can be an issue. Fungi have also been known to
develop resistance to antifungal drugs, such as fluconazole and
echinocandins. A straightforward and effective alternative to
conventional antifungal reagents is needed to limit the spread and
impact of fungi.
SUMMARY
[0005] The nanofibers of the presently disclosed subject matter
have been shown to have antifungal activity.
[0006] In some aspects, the presently disclosed subject matter
provides a surface coating composition comprising nanofibers of
polyacrylonitrile (PAN and/or cellulose acetate (CA) in an amount
sufficient to inhibit or prevent the growth of a fungus on a
surface coated with said surface coating composition. In some
embodiments, the presently disclosed subject matter provides an
antifungal surface treated with PAN nanofibers and/or CA
nanofibers. In some embodiments, the antifungal surface is treated
with an antifungal effective amount of nanofibers of
polyacrylonitrile and/or cellulose acetate.
[0007] In some aspects, the presently disclosed subject matter
provides a method for the antifungal treatment of a surface
comprising applying an antifungal effective amount of a composition
comprising nanofibers of polyacrylonitrile and/or cellulose acetate
to a surface in need of such antifungal treatment. In some
embodiments, the presently disclosed subject matter provides for
the use of polyacrylonitrile nanofibers and/or cellulose acetate
nanofibers on a surface, including but not limited to an indoor or
outdoor surface: textiles, shoes, furniture, building, plants or
any surface on which fungi can grow.
[0008] These and other embodiments are described in greater detail
in the detailed description which follows.
[0009] Accordingly, it is an object of the presently disclosed
subject matter to provide nanofibers having antifungal
activity.
[0010] An object of the presently disclosed subject matter having
been stated hereinabove, and which is achieved in whole or in part
by the presently disclosed subject matter, other objects will
become evident as the description proceeds when taken in connection
with the accompanying drawings as best described herein below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1A illustrates a scanning electron microscope (SEM)
image of yeast cells cultured on a PAN substrate after 30 min
incubation wherein the PAN substrate is a PAN solid film.
[0012] FIG. 1B illustrates an SEM image of yeast cells cultured on
a PAN substrate after 30 min incubation wherein the PAN substrate
is a microfibrous mat.
[0013] FIG. 1C illustrates an SEM image of yeast cells cultured on
a PAN substrate after 30 min incubation wherein the PAN substrate
is a nanofibrous mat.
[0014] FIG. 2 is a bar graph showing the effect of different PAN
substrates on SK1 cell growth as represented by colony forming
units (CFUs) starting at OD.sub.600=0.05 after incubation. The
measured CFU of each sample was normalized according to the CFU of
SK1 culture without substrate (left bar) and the data are shown as
a CFU ratio.
[0015] FIG. 3A illustrates an SEM image of images of SK1 yeast
cells cultured on PAN nanofibrous mat after 30 min contact.
[0016] FIG. 3B illustrates an SEM image of images of W303 yeast
cells cultured on PAN nanofibrous mat after 30 min contact.
[0017] FIG. 4 is a graph showing the effect different PAN
substrates (nanofibrous mat, solid film, microfibrous mat and
control without a PAN substrate) on SK1 cell growth after an eight
hour incubation, as represented by the optical density
(OD.sub.600).
[0018] FIG. 5 is a graph showing the effect of different PAN
substrates (no substrate, PAN microfibrous mat and PAN nanofibrous
mat) on the growth of SK1 cells after incubation, as represented by
MTT absorbance.
[0019] FIG. 6 is a graph of variation in fluorescence intensity of
MitoTracker Red stained SK1 cells compared to control after 0 and
10 minutes exposure to a PAN nanofibrous mat (ESPAN).
[0020] FIG. 7A is a graph showing the effect of different masses of
substrates: CA nanofibrous mat, CA film, cellulose nanofibrous mat,
cellulose film, PAN nanofibrous mat, PAN film and control on the
growth of SK1 cell cultures after 16 hour incubation, as
represented by optical density (OD.sub.600).
[0021] FIG. 7B is a graph showing the effect of different masses of
substrates: CA nanofibrous mat, CA film, cellulose nanofibrous mat,
cellulose film, PAN nanofibrous mat, PAN film and control on the
growth of C. albicans cell cultures after 16 hour incubation, as
represented by optical density (OD.sub.600).
DETAILED DESCRIPTION
[0022] The presently disclosed subject matter will now be described
more fully. The presently disclosed subject matter can, however, be
embodied in different forms and should not be construed as limited
to the embodiments set forth herein below and in the accompanying
Examples. Rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the
scope of the embodiments to those skilled in the art.
[0023] All references listed herein, including but not limited to
all patents, patent applications and publications thereof, and
scientific journal articles, are incorporated herein by reference
in their entireties to the extent that they supplement, explain,
provide a background for, or teach methodology, techniques, and/or
compositions employed herein.
I. Definitions
[0024] While the following terms are believed to be well understood
by one of ordinary skill in the art, the following definitions are
set forth to facilitate explanation of the presently disclosed
subject matter.
[0025] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood to one of
ordinary skill in the art to which the presently disclosed subject
matter belongs.
[0026] Following long-standing patent law convention, the terms
"a", "an", and "the" refer to "one or more" when used in this
application, including the claims.
[0027] The term "and/or" when used in describing two or more items
or conditions, refers to situations where all named items or
conditions are present or applicable, or to situations wherein only
one (or less than all) of the items or conditions is present or
applicable.
[0028] The use of the term "or" in the claims is used to mean
"and/or" unless explicitly indicated to refer to alternatives only
or the alternatives are mutually exclusive, although the disclosure
supports a definition that refers to only alternatives and
"and/or."
[0029] As used herein "another" can mean at least a second or
more.
[0030] The term "comprising", which is synonymous with "including,"
"containing," or "characterized by" is inclusive or open-ended and
does not exclude additional, unrecited elements or method steps.
"Comprising" is a term of art used in claim language which means
that the named elements are essential, but other elements can be
added and still form a construct within the scope of the claim.
[0031] As used herein, the phrase "consisting of" excludes any
element, step, or ingredient not specified in the claim. When the
phrase "consists of" appears in a clause of the body of a claim,
rather than immediately following the preamble, it limits only the
element set forth in that clause; other elements are not excluded
from the claim as a whole.
[0032] As used herein, the phrase "consisting essentially of"
limits the scope of a claim to the specified materials or steps,
plus those that do not materially affect the basic and novel
characteristic(s) of the claimed subject matter.
[0033] With respect to the terms "comprising", "consisting of", and
"consisting essentially of", where one of these three terms is used
herein, the presently disclosed subject matter can include the use
of either of the other two terms.
[0034] As used herein, the term "about", when referring to a value
is meant to encompass variations of in one example .+-.20% or
.+-.10%, in another example .+-.5%, in another example .+-.1%, and
in still another example .+-.0.1% from the specified amount, as
such variations are appropriate to perform the disclosed
methods.
[0035] In addition, all ranges disclosed herein are to be
understood to encompass any and all subranges subsumed therein. For
example, a stated range of "1.0 to 10.0" should be considered to
include any and all subranges beginning with a minimum value of 1.0
or more and ending with a maximum value of 10.0 or less, e.g., 1.0
to 5.3, or 4.7 to 10.0, or 3.6 to 7.9.
[0036] All ranges disclosed herein are also to be considered to
include the end points of the range, unless expressly stated
otherwise. For example, a range of "between 5 and 10", "from 5 to
10" or "5-10" should generally be considered to include the end
points 5 and 10.
[0037] Further, when the phrase "up to" is used in connection with
an amount or quantity, it is to be understood that the amount is at
least a detectable amount or quantity. For example, a material
present in an amount "up to" a specified amount can be present from
a detectable amount and up to and including the specified
amount.
[0038] As used herein, "nanofibers" or "nanofibrous" refers to
fibers with diameters from about 100 nm to about 1000 nm. The
nanofibers described herein generally are typically prepared by
electrospinning of spin dope comprising polyacrylonitrile (PAN) or
cellulose acetate (CA). Alternate methods of preparation of
nanofibers are known in the art. In some embodiments, the
nanofibers are characterized by average diameters of no more than
about 750 nm, no more than about 500 nm, no more than about 250 nm.
In other embodiments, the nanofibers are characterized by average
diameters of between about 100 nm to about 250 nm, or between about
100 nm to about 500 nm, or between about 100 nm to about 750 nm, or
between about 250 nm and about 750 nm or between about 300 nm and
700 nm or between about 400 nm and about 600 nm.
[0039] As used herein an "antifungal effective amount" of an
antifungal composition refers to a composition comprising an amount
of nanofibers of polyacrylonitrile and/or nanofibers of cellulose
acetate sufficient to inhibit growth of fungus.
[0040] As used herein, "inhibit growth of fungus" means that the
growth of fungus in the presence of the nanofibers disclosed herein
is slower than the growth of fungus not in the presence of the
nanofibers. In one variation, inhibition of growth reflects that
the presence of nanofibers kills fungal cells, thereby reducing its
growth. In one aspect, the growth of fungus is slowed in the
presence of the nanofibers disclosed herein, where fungal cell
growth is measured by a typical approach, such as OD.sub.600 of
cell culture, where a lower OD.sub.600 corresponds to the presence
of fewer cells and correspondingly a higher cell inhibition effect.
Alternately, fungal cell growth is halted, wherein no additional
growth of fungus is observed after the application of the
nanofibers disclosed herein, e.g. no additional cell growth is
measured. In another alternative, the growth of fungus is reversed,
such that existing or applied fungal cells are killed due to or die
in the presence of the nanofibers disclosed herein.
[0041] In some embodiments, the growth of fungi in the presence of
the nanofibers of the present application is demonstrably slowed
and/or fungi are killed when the fungal cell viability, as
represented by the OD.sub.600 of the solution of fungi exposed to
nanofibers of the present application is no more than about 75% of
the OD.sub.600 of the (control) solution of fungi not exposed to
nanofibers of the present application. Alternately, the OD.sub.600
of the exposed fungi solution is no more than about 60%, no more
than about 50%, no more than about 40%, no more than about 30%, no
more than about 20% or no more than about 10% of the OD.sub.600 of
the exposed fungi solution. In some embodiments, the growth of
fungi in the presence of the nanofibers of the present application
is demonstrably slowed and/or fungi are killed when the normalized
Colony Forming Unit ratio (CFU) of fungi exposed to nanofibers of
the present application is no more than about 60% of the CFU of
(control) fungi not exposed to nanofibers of the present
application. Alternately, the CFU of the exposed fungi is no more
than about 50%, no more than about 40%, no more than about 30%, no
more than about 25%, no more than about 20%, no more than about
15%, or no more than about 10% the CFU of unexposed fungi. In other
embodiments, the growth of fungi in the presence of the nanofibers
of the present application is demonstrably slowed and/or fungi are
killed when the metabolic activity, as represented by MTT
absorbance in an MTT assay, of the fungi exposed to nanofibers of
the present application is no more than about 50% of the MTT
absorbance of (control) fungi not exposed to nanofibers of the
present application. Alternately, the MTT absorbance of the exposed
fungi is no more than about 40%, no more than about 35%, no more
than about 30%, no more than about 25%, no more than about 20%, no
more than about 15%, or no more than about 10% the MTT absorbance
of unexposed fungi.
[0042] As used herein, "exposed to fungus" means that fungal cells
come in physical contact with the presently disclosed nanofibers.
In some variations, fungal cells are in a solution that comes in
contact with a composition comprising the nanofibers of the present
application. In another variation, the fungi
[0043] As disclosed herein, the interactions between each of PAN
nanofibers and CA nanofibers with baker's yeast, Saccharomyces
cerevisiae, and with Candida albicans were investigated. S.
cerevisiae is a model genetic microorganism and type of fungus
central to the fermentation industry; C. albicans is a dimorphic
fungus responsible for candidiasis in humans. As disclosed herein,
nanofibrous PAN and nanofibrous CA adversely affected the growth,
morphology, and viability of these representative fungi. The
demonstrated antifungal activity of PAN nanofibrous mats was in
contrast to both PAN film and PAN microfibrous mats, neither of
which demonstrated the same antifungal activity. Similarly, CA
nanofibers demonstrated antifungal activity, while a CA cast film
did not lead to decreased cell viability. As reported herein,
antifungal activity of other nanofibrous mats prepared from a
variety of starting materials, including amidoxime surface modified
PAN, carbon, cellulose, cellulose with embedded TiO.sub.2
(Cellulose_TiO.sub.2), and cellulose acetate with embedded
TiO.sub.2 (CA_TiO.sub.2) were also investigated. Each of PAN
nanofibers and CA nanofibers demonstrated notable antifungal
activity. Further, nanofibrous PAN and nanofibrous CA demonstrated
antifungal activity without the addition of separate agents, such
as amidoxime, or metal centers, including but not limited to
TiO.sub.2. Notably, nanofibrous CA demonstrated increased
antifungal activity compared to CA with embedded TiO.sub.2
(CA_TiO.sub.2).
[0044] In some aspects, the presently disclosed subject matter
provides a surface coating composition comprising nanofibers of
polyacrylonitrile and/or cellulose acetate in an amount sufficient
to inhibit or prevent the growth of a fungus on a surface coated
with said surface coating composition. In one embodiment, the
nanofibers are electrospun polyacrylonitrile nanofibers; in another
embodiment, the nanofibers are electrospun cellulose acetate
nanofibers. In another embodiment, the composition does not contain
an antifungal agent selected from the group consisting of silver
nanoparticles, polyene antifungals, azole antifungals, allylamine
antifungals, or echinocandin antifungals.
[0045] In some aspects, the presently disclosed subject matter
provides a method for the antifungal treatment of a surface
comprising applying an antifungal effective amount of a composition
comprising nanofibers of polyacrylonitrile and/or cellulose acetate
to a surface in need of antifungal treatment. In one embodiment,
the surface is contaminated with a fungus or was exposed to a
fungus. In another embodiment, the antifungal treatment comprises
slowing or preventing fungal growth on the surface. In one
embodiment, the nanofibers are electrospun polyacrylonitrile
nanofibers; in another embodiment, the nanofibers are electrospun
cellulose acetate nanofibers. In another embodiment, the
composition does not contain an antifungal agent selected from the
group consisting of silver nanoparticles, polyene antifungals,
azole antifungals, allylamine antifungals, or echinocandin
antifungals.
[0046] In some aspects, the presently disclosed subject matter
provides an antifungal surface treated with an antifungal effective
amount of nanofibers of polyacrylonitrile and/or cellulose acetate.
In one embodiment, the surface is porous, semi-porous or
non-porous. In another embodiment, the surface is metal, wall
board, ceiling tile, paper, textile, concrete, stone, brick, wood,
plastic, ceramic, or leather. In another embodiment, the surface is
a textile; in one variation, the surface is a garment, bedding or
part of a shoe. In one embodiment, the nanofibers are electrospun
polyacrylonitrile nanofibers; in another embodiment, the nanofibers
are electrospun cellulose acetate nanofibers. In yet another
embodiment, the surface is a fibrous material and the nanofibers
are electrospun polyacrylonitrile nanofibers and/or electrospun
cellulose acetate nanofibers. In another embodiment, the
composition does not contain an antifungal agent selected from the
group consisting of silver nanoparticles, polyene antifungals,
azole antifungals, allylamine antifungals, or echinocandin
antifungals.
[0047] In some aspects, the presently disclosed subject matter
provides a surface coating composition comprising nanofibers of
polyacrylonitrile or nanofibers of cellulose acetate. In one
embodiment, the surface coating composition comprises nanofibers of
polyacrylonitrile or nanofibers of cellulose acetate in an amount
sufficient to inhibit or prevent the growth of a fungus on a
surface coated with said surface coating composition. In another
embodiment, the nanofibers are electrospun polyacrylonitrile
nanofibers; in yet another embodiment, the nanofibers are
electrospun cellulose acetate nanofibers.
[0048] In other aspects, the presently disclosed subject matter
provides a method for the antifungal treatment of a surface
comprising applying an antifungal effective amount of a composition
comprising nanofibers of polyacrylonitrile or nanofibers of
cellulose acetate to a surface in need of antifungal treatment. In
one embodiment, the surface is contaminated with a fungus; in
another embodiment, the surface was exposed to a fungus; in yet
another embodiment, the surface will be exposed to a fungus; in a
further embodiment, the surface is at risk of being exposed to a
fungus. In one embodiment, the nanofibers are electrospun
polyacrylonitrile nanofibers; in another embodiment, the nanofibers
are electrospun cellulose acetate nanofibers.
[0049] In still other aspects, the presently disclosed subject
matter provides a method for slowing or preventing fungal growth on
a surface comprising applying to the surface a composition
comprising nanofibers of polyacrylonitrile or nanofibers of
cellulose acetate. In one embodiment, the composition comprises an
antifungal effective amount of electrospun polyacrylonitrile
nanofibers; in another embodiment, the composition comprises an
antifungal effective amount of electrospun cellulose acetate. In
one embodiment, the surface is contaminated with a fungus; in
another embodiment, the surface was exposed to a fungus; in yet
another embodiment, the surface will be exposed to a fungus; in a
further embodiment, the surface is at risk of being exposed to a
fungus.
[0050] In one variation of any of the disclosed aspects or
embodiments, the composition comprising nanofibers of
polyacrylonitrile or nanofibers of cellulose acetate is a solution
or a film. In one such variation, the composition is a paint
comprising electrospun polyacrylonitrile nanofibers or electrospun
cellulose acetate nanofibers.
[0051] In some embodiments, the presently disclosed subject matter
provides an antifungal surface treated with an antifungal effective
amount of nanofibers of polyacrylonitrile or cellulose acetate. In
some embodiments, the nanofibers are electrospun polyacrylonitrile
nanofibers; in other embodiments, the nanofibers are electrospun
cellulose acetate nanofibers.
[0052] In one variation of any of the disclosed aspects or
embodiments, electrospun polyacrylonitrile nanofibers and/or
electrospun cellulose acetate nanofibers are the only antifungal
components of the antifungal composition. In yet another
embodiment, electrospun polyacrylonitrile nanofibers are the only
antifungal component of the antifungal composition; in an alternate
embodiment, electrospun cellulose acetate nanofibers are the only
antifungal component of the antifungal composition.
[0053] In one variation of any of the disclosed aspects or
embodiments, the disclosed composition comprising nanofibers of
polyacrylonitrile and/or nanofibers of cellulose acetate does not
include any other agent with antifungal activity. Such known
antifungal agents include silver nanoparticles, as well as chemical
agents, including but not limited to polyene antifungals (e.g.
amphotericin B), azole (e.g. imidazole, triazole or thiazole)
antifungals, allylamine antifungals, or echinocandin antifungals.
In other embodiments, the composition includes another antifungal
agent disclosed herein. In still other embodiments, the composition
includes a chemical antifungal agent, such as an azole antifungal
or an echinocandin antifungal.
[0054] In one variation of any of the disclosed aspects or
embodiments, the surface is porous, semi-porous or non-porous. In
yet another variation, the surface is an indoor or outdoor surface.
In another variation, the surface includes, but is not limited to
metal, wall board, ceiling tile, paper, textile, concrete, stone,
brick, wood, plastic, ceramic, and leather. In some embodiments,
the surface is a garment, bedding, part of a shoe or a shoe insole.
In some variations, the surface is a shoe insole, which is
replaceable or is permanently attached to the shoe. In another
variation, the surface is a textile, including, but not limited to
a non-woven textile or a woven textile or a natural or synthetic
textile. In yet another variation, the surface is a garment, such
as medical scrubs, socks, hosiery, a mask, a lab coat or a glove.
In another variation, the surface is a type of bedding, such as,
but not limited to, pillow, pillowcase, sham, comforter, quilt,
duvet cover, throw, mattress pad, sheet, blanket, mattress topper,
or mattress protector. In another variation, the surface is a
floor, a wall, a sink, a table, a bucket, or a countertop.
[0055] As disclosed herein, application to a surface can include
incorporation of the nanofibers disclosed herein into the material
comprising the surface, such as, for example, a porous or
semi-porous surface or woven textile. In each material, the
nanofiber-containing composition can occupy void space in the
material, thus providing nanofiber antifungal functionality to
otherwise unused space. Such `internal` as well as `external`
distribution of the nanofibers can increase the capacity to control
fungal cell growth by increasing the total amount of nanofibers in
the product, yielding nanofibers distributed not only on the
surface, but also within the material.
[0056] In one variation of any of the disclosed aspects or
embodiments, the nanofibers have an average diameter of between
about 100 nm and 1000 nm or between about 300 nm and about 700 nm
or between about 400 nm and about 600 nm. In another embodiment,
the nanofibers have an average diameter of no more than about 1000
nm, of no more than about 750 nm, of no more than about 500 nm.
[0057] In one variation of any of the disclosed aspects or
embodiments, the nanofibers of polyacrylonitrile or cellulose
acetate can be combined with one or more other antifungal agents,
such as a chemical agent, including but not limited to polyene
antifungals (e.g. amphotericin B), azole (e.g. imidazole, triazole
or thiazole) antifungals, allylamine antifungals, or echinocandin
antifungals or antifungal agents such as silver nanoparticles.
[0058] As described further hereinbelow, nanofibers described
herein can be made in any manner not inconsistent with the
objectives of the present disclosure. The nanofibers may especially
advantageously be made by electrospinning as disclosed herein.
EXAMPLES
[0059] The following Examples have been included to provide
guidance to one of ordinary skill in the art for practicing
representative embodiments of the presently disclosed subject
matter. In light of the present disclosure and the general level of
skill in the art, those of skill can appreciate that the following
Examples are intended to be exemplary only and that numerous
changes, modifications, and alterations can be employed without
departing from the scope of the presently disclosed subject
matter.
1. Materials
[0060] Polyacrylonitrile (PAN), Cellulose acetate (CA),
N,N-Dimethylformamide (DMF), sodium phosphate dibasic
(Na.sub.2HPO.sub.4) and sodium phosphate monobasic
(NaH.sub.2PO.sub.4) were purchased from Sigma-Aldrich (St. Louis,
Mo., USA). PAN microfibers, having an average fiber diameter of
about 10 .mu.m, were purchased from Xi'an Zhongrun Architectural
Technology Corporation (China). S. cerevisiae yeast strain SK1
(ATCC stock number: 204722; genotype: MATalMATalpha HO can1(r) gal2
cup (s)), S. cerevisiae yeast strain W303 (ATCC stock number:
208352; genotype: MATaade2-1ura3-1
his3-11trp1-1leu2-31eu2-112can1-100) were obtained from American
Type Culture Collection), and C. albicans yeast strain, (ATCC stock
number 10231) were obtained from American Type Culture Collection.
Paraformaldehyde was purchased from Ted Pella, Inc. (Redding,
Calif., USA). Phosphate buffered saline (PBS) is prepared by mixing
1 M NaH.sub.2PO.sub.4 and 1 M Na.sub.2HPO.sub.4 aqueous solutions
at pH=7.4.
2. Substrate Preparation
[0061] Polyacrylonitrile (PAN) nanofibers with an average diameter
of about 500 nm were obtained by electrospinning 10 wt % PAN
solution in dimethylformamide at a voltage of 15 KV and feeding
rate of 1.0 ml/hr. PAN solid films were obtained by casting the PAN
spinning solution onto a TEFLON.RTM. plate and drying at room
temperature. PAN microfibers were rinsed with acetone and then were
randomly stuck together with a small amount of DMF to make a
nonwoven microfibrous mat.
[0062] Cellulose acetate (CA) nanofibers were obtained by
electrospinning a solution comprising 20 wt. % cellulose acetate in
a mixture solvent of 1:1 tetrahydrofuran and dimethyl sulfoxide
plus trace amount of sodium citrate at a rate of 1.2 ml/hr and a
voltage of 22 KV. The electrospun nanofibers were collected over
rotating drum collector and good homogenous fibers were obtained.
Cellulose acetate solid films were obtained by casting the CA
spinning solution onto a TEFLON.RTM. plate and drying at room
temperature.
[0063] Cellulose nanofibers were prepared by treating cellulose
acetate nanofibers with 0.05 M NaOH overnight and rinsing the
resulting cellulose nanofibers and then drying. Cellulose films
were obtained by treating a cellulose acetate film with 0.05 M NaOH
overnight and rinsing the resulting cellulose film and drying at
room temperature.
3. Cell Culture
[0064] 3.1 SK1 Cell Growth
[0065] SK1 cells were grown overnight in 20 ml Yeast extract,
Peptone, and Dextrose medium (YPD, which provides the source of
amino acids, nucleotide precursors, vitamins, and metabolites for
cell growth) in a shaking incubator at 200 r.p.m at room
temperature for 18 hours. The culture was diluted in the next day
to OD.sub.600=0.1-0.16 then left to grow at 28.degree. C. in a
shaking incubator at 200 r.p.m to mid log phase of growth
(OD.sub.600=0.4-0.6).
[0066] 3.2 W303 Cell Growth
[0067] W303 cells were grown overnight in 5 ml yeast extract,
peptone, and dextrose medium (YPD, the source of amino acids,
nucleotide precursors, vitamins, and metabolites that are needed
for cell growth) in a shaking incubator at room temperature for 24
hours. The culture was diluted with 45 ml YPD the next day. The
culture medium was maintained in the incubator until the yeast
strains grew to mid log phase (OD.sub.600=.about.0.4).
[0068] 3.3 C. albicans Cell Growth
[0069] C. albicans cells were cultured on Sabouraud Dextrose Agar
(SBD) solid agar plate for 48 hrs in an incubator at 30.degree. C.
and stored in a refrigerator for 3 days before use, as disclosed
herein.
4. Characterization
[0070] 4.1. Cell and Substrate Morphology
[0071] PAN solid film, PAN microfibrous mat, and PAN nanofibrous
mat were cut into 6 mm.times.4 mm pieces and glued to glass chips
respectively. The glass chips were further individually glued onto
petri dishes. Culture of SK1 strains or W303 strains was then
transferred to corresponding petri dishes. After 30 min contact,
the substrates were rinsed softly with DI water and placed in
paraformaldehyde fixing solution. These samples were taken out of
fixing solution after overnight immersion and left to dry at room
temperature with the aid of DRIERITE.TM. desiccant. Morphology of
SK1 cells, W303 cells, and substrates were examined by a Carl Zeiss
Auriga-BU FIB field emission scanning electron microscope. Before
SEM imaging, all surfaces were sputter-coated with gold to avoid
charge accumulation.
[0072] 4.2. Colony Forming Units (CFU)
[0073] Population of cell in SK1 culture was characterized by
measuring light absorption of the culture at wavelength of 600 nm
(OD.sub.600). SK1 cells were cultured overnight to
OD.sub.600=.about.1.8 and then diluted to OD.sub.600=0.1 and
OD.sub.600=0.05, respectively. PAN solid film, microfibrous mat,
and nanofibrous mat were cut into approximately 3.5 cm.times.2.2 cm
pieces and placed individually in a well on a six-well culture
plate. 6 ml SK1 cell culture at OD.sub.600=0.1 or OD.sub.600=0.05
were then transferred respectively into corresponding wells
including one empty well for control purpose. CFU experiments were
conducted with the two respective SK1 cultures under mechanical
shaking. Mechanical shaking was done after the cell culture plate
was placed in a shaker that was set at 150 r.p.m. Mechanical
shaking was performed in order to avoid large cell deposition on
substrates. After 1 hour incubation, cell cultures were removed
from respective well and underwent a series of dilutions. 100 .mu.l
of respective final cell culture dilution were taken out and spread
onto a petri dish with solid agar. Corresponding agar petri dish
was incubated at 26.degree. C. for 48 hours before cell colonies
were counted manually. CFU assays were repeated three times for
each substrate and the results were analyzed statistically by using
t test calculator from GRAPHPAD.TM. software.
[0074] 4.3. Optical Density Test
[0075] In optical density test, SK1 cells were cultured overnight
and then diluted to one tenth and one hundredth, respectively. Two
pieces of PAN nanofibrous mats (10 mg) were cut from the
electrospun product and placed in a 70 ml flask, respectively. 20
ml YBD media plus 20 .mu.l of respective diluted cell culture were
then poured into each flask. The same amount of YBD media and
respective diluted cell cultures without PAN nanofibrous mats were
placed in another two flasks and served as control samples. These
flasks were then placed in a shaking incubator at 26.degree. C. for
18 hours before OD test. OD.sub.600 of all these SK1 cell cultures
was characterized through a Thermo Scientific NANODROP.TM. 2000C
spectrophotometer. The above-described optical density test was
repeated three times with fresh PAN nanofibrous mats for each
diluted cell culture and average OD data were reported.
[0076] 4.4. Live/Dead Cells Viability (In Vitro) Assays
[0077] SK1 cells were cultured overnight and 10 ml of the culture
was taken out for test and then 10 .mu.l acridine orange (10 mg/ml)
was added into the cell culture. The culture was then diluted to
OD.sub.600=0.1 by using mixture of propidium iodide (5 mg/ml) and
YPD media at volume ratio 1:1000. PAN nanofibrous mat
(approximately 6 mm.times.4 mm) was introduced to the culture
mixture and the whole system was incubated for 10 minutes prior to
confocal imaging of the PAN nanofibrous mat by Zeiss Axiom Plan
spinning disc confocal microscope. Fluorescent images from the
confocal microscope were processed by Image J software for cell
counting.
Example 1
Effect of Different PAN Materials on Growth of Fungal Cells,
SK1
[0078] To investigate the interaction between yeast cells and
electrospun PAN nanofibrous mat, S. cerevisiae yeast strain SK1 was
cultured and applied to each of a PAN nanofibrous mat, a PAN film
and a PAN microfibrous mat. The PAN nanofibrous mat was prepared by
electrospinning PAN fibers with average diameter of .about.500 nm,
while the PAN microfibrous mat was comprised of fibers having an
average diameter of about 10 .mu.m. The PAN film was prepared via
solution casting and the resultant films showed a solid but
somewhat crimpled surface. SK1 cells grew normally upon 30 min
contact with the PAN film and PAN microfibrous mat and generally
grew bigger as they aged (FIGS. 1A and 1B). On these control
surfaces, mid-log phase growth SK1 cells exhibited an ellipsoidal
shape with varied sizes in the range of 3-4 micrometers,
characteristic of normal healthy cells. However, SK1 yeast cells
exhibited a distinctly flattened, abnormal, morphology after only
30 minutes incubation exposure to the electrospun PAN nanofibrous
mat (FIG. 1C). Cell morphology studies suggest that the PAN
nanofibrous mat inhibit yeast cell growth without needing any
external aid such as antifungal agents, indicating a valuable
antifungal functionality of electrospun PAN nanofibrous mats.
[0079] To determine whether (a) malformed SK1 cells were bound to
the electrospun PAN nanofibrous mat and exhibited reduced viability
or (b) SK1 cells' membrane became compromised due to contact with
electrospun PAN nanofibrous mat, two additional experiments were
performed--a colony forming assay (CFU) and a mitochondrial
morphology/membrane potential assay.
[0080] CFU is a standard biological assay that measures the number
of live microbes in a unit volume (colony units per milliliter). To
assess the viability of yeast on electrospun nanofibrous mat, a CFU
experiment was performed with SK1 strain culture at OD.sub.600=0.05
(.about.1.5.times.10.sup.6 cells/ml). Optical Density of all SK1
cell cultures was characterized using a NANODROP.TM. 2000C
spectrophotometer (ThermoFischer Scientific, Waltham, Mass. USA).
OD.sub.600 is commonly used to characterize cell population per
culture volume by measuring light absorption of cell culture at
wavelength of 600 nm. After 1 hour contact and incubation, a
significant (66%) reduction in the number of cells incubated with
the electrospun PAN nanofibrous mat was observed compared to (a)
control including no substrate, (b) incubated with a PAN film, and
(c) incubated with a PAN microfibrous mat (FIG. 2). As shown, PAN
nanofibrous mat was capable of significantly inhibiting yeast cell
survival and growth.
[0081] OD.sub.600 of the SK1 cell cultures was examined with and
without an electrospun PAN nanofibrous mat during incubation. To
perform these experiments, starting SK1 cultures (OD.sub.600=1.83)
were diluted to a high cell concentration (OD.sub.600=0.37) and low
cell concentration (OD.sub.600=0.04) in YPD nutrient solution, with
or without 10 mg nanofibrous PAN and incubated for 18 hours.
Optical densities of the cell cultures were measured. (Table 1) In
control cultures (without nanofibrous PAN), OD.sub.600 of both the
high cell concentration and the low cell concentration grew
robustly. In the high cell concentration control culture OD.sub.600
increased from 0.37 to 2.2. In the presence of nanofibrous PAN,
however, OD.sub.600 dropped from 2.2 to 0.5. In the culture started
with fewer cells, OD.sub.600 reduction was even more pronounced. In
the presence of nanofibrous PAN, zero optical density
(OD.sub.600=0) was recorded, compared to 0.3 for the corresponding
low cell concentration control. (Table 1)
TABLE-US-00001 TABLE 1 OD.sub.600 of SK1 cell cultures incubated
with or without electrospun PAN nanofibrous mat After incubation
Before incubation Culture with electrospun Starting culture Control
culture PAN nanofibrous mat 0.37 2.2 0.5 0.04 0.3 0.0
[0082] The CFU and OD.sub.600 results were consistent with changes
in cell morphology. To investigate the effect of nanofibrous PAN on
the integrity of the yeast cell, mitochondrial morphology/membrane
potential assay (commonly known as live/dead cell assay) was
conducted by using a mixture of two nucleic acid fluorescent
stains, propidium iodide (PI) and acridine orange (AO). PI has
maximum excitation at 535 nm and maximum emission at 617 nm. PI is
the basis of cell viability through this standard live/dead essay.
PI is a cell impermeable dye, but enters cell through ruptured cell
membranes and binds with DNA, emitting red radiation. AO has
maximum excitation at 488 nm and maximum emission at 518 nm. AO can
permeate into nucleated cells, bind with DNA and emit green
radiation. Confocal laser scanning microscopy (CLSM) is a
fluorescence microscopy used to view emitted radiations from
live/dead cells, in which red spots indicate dead cells and green
spots indicate live cells. In the live/dead cell assay, a PAN
nanofibrous mat was introduced to SK1 cell culture with AO and PI
and the whole system was incubated for 10 min. Based on an analysis
of the fluorescent images of PAN nanofibrous mat after incubation,
74% SK1 cells emitted red radiation, indicating loss of viability.
Thus nanofibrous PAN hindered cell viability within 10 min of
contact. SK1 cells were all alive (100%) on PAN film after the same
time contact. The live/dead cell assay confirmed that most of yeast
cells on the surface of PAN nanofibrous mat were dead, consistent
with the CFU and OD.sub.600 measurements.
[0083] S. cerevisiae SK1 cell growth in cultures with a PAN
nanofibrous mat during first 8 hours was investigated. Normally the
number of cells in a culture solution continues to increase with
incubation time when enough nutrient is present. The blank control
of SK1 culture as well as SK1 cultures with PAN film and PAN
microfibrous mat showed a similar optical density growth profile
versus time (FIG. 4). The growth profile of the SK1 culture with a
PAN nanofibrous mat significantly deviated from that of the blank
control. A much lower optical density was observed for the cell
culture with PAN nanofibrous mat. The cell number drop at the
beginning of the 8th hour was notable. The lower SK1 cell growth
profile with PAN nanofibrous mat, as well as the cell number drop,
is consistent with the immediate inhibition of yeast cell growth
upon contact with the PAN nanofibrous mat. Without being bound by
theory, if cell retention by the PAN nanofibrous mat had been
observed, there would have been a large cell number increase after
first couple of hours due to cells entering the culture solution
due to mechanical shaking and the `freed` cells would be expected
to thereafter grow robustly.
[0084] The CFU and optical density results were consistent with
observed changes in cell morphology and growth inhibition of yeast
cells by the PAN nanofibrous mat. To explore cell viability
directly on a PAN nanofibrous mat, a colorimetric assay for
assessing SK1 cell metabolic activity was performed using a
tetrazolium dye
(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT
assay). Reduction of tetrazoium salts is widely accepted as a
reliable way to examine cell proliferation. MTT is reduced by
metabolically active cells and the purple formazan product can be
quantified by spectrophotometry. SK1 cells exposed to a PAN
nanofibrous mat showed much lower MTT absorbance (FIG. 5) compared
to SK1 cells exposed to a PAN microfibrous mat or to no substrate.
Based on the MTT results, SK1 cells with a PAN nanofibrous mat
showed much lower metabolic activity as well as a lowered
proliferation rate, consistent with the inhibiting role of PAN
nanofibrous mat when in contact with fungal cells.
[0085] A red-fluorescent dye, MitoTracker Red FM, was used to
characterize SK1 cells viability. When cells are incubated with the
cell-permeable MitoTracker Red, the dye passively diffuses across
live cells' plasma membrane and accumulates in active mitochondria.
Low intensity of fluorescence emission observed therefrom is an
indication of low mitochondrial membrane potential and low
mitochondrial membrane potential correspondingly indicates
apoptosis induction in cells. Compared to a blank control sample, a
significant fluorescence intensity reduction of MitoTracker Red
stained SK1 cells on PAN nanofibrous mat was observed after 10 min
contact (FIG. 6). Thus, without being bound by theory, it is
presumed that SK1 cells became much less metabolically active or
severely stressed on PAN nanofibrous mat. It was noteworthy that
PAN nanofibrous mat could significantly inhibit cell's viability as
soon as 10 min contact.
[0086] The combined experimental results demonstrated that
nanofibrous PAN has an intrinsic antifungal activity. Compared to
PAN film and PAN microfibrous mat, each of which provide solid
support to yeast cells, it was observed that nanofibrous PAN
provided limited and asymmetrical contact to the yeast cells.
Without being bound by theory, yeast cells may experience
differentiated adhesion between different parts of the cell and
adjacent PAN nanofibers, thereby inducing internal tension.
Interaction of yeast cells with the PAN nanofibrous mat resulted in
lower cell metabolic activity, lower proliferation and eventually
cell rupture and/or cell death.
Example 2
Effect of Different Nanofibrous Mats on SK1 Cell Growth Via Optical
Density Test
[0087] To evaluate whether the effect of nanofibrous PAN was due
solely to the size of the electrospun fibers, different nanofibrous
mats were prepared and the growth of SK1 cells on the different
nanofibers were evaluated.
[0088] In this study, SK1 cells were cultured overnight and then
diluted to one tenth (OD.sub.600=0.37) and one hundredth
(OD.sub.600=0.04)), respectively. Samples of electrospun
nanofibrous mats (10 mg) of each of: PAN, amidoxime surface
modified PAN, carbon, cellulose, cellulose acetate, cellulose with
embedded TiO.sub.2 (Cellulose_TiO.sub.2), and cellulose acetate
with embedded TiO.sub.2 (CA_TiO.sub.2) mats were placed in a 70 ml
flasks, respectively. YBD media (20 mL) plus 20 .mu.l of diluted
SK1 cell cultures were poured into each flask. The control sample
was prepared with 20 mL YBD media and 20 .mu.l of diluted SK1 cell
culture without nanofibrous mats in another flask. The flasks were
then placed in a shaking incubator at 26.degree. C. for 18 hours
before conducting an Optical Density test at 600 nm (`OD.sub.600`).
OD.sub.600 of all SK1 cell cultures was characterized using a
NANODROP.TM. 2000C spectrophotometer (ThermoFischer Scientific,
Waltham, Mass. USA). The optical density test was repeated three
times with fresh nanofibrous mats for each diluted cell culture and
average OD data calculated. (Table 2 and Table 3) As shown,
nanofibrous cellulose acetate demonstrated notable antifungal
activity compared to control.
TABLE-US-00002 TABLE 2 OD.sub.600 of SK1 strain after 18 hr contact
with electrospun nanofibrous mats (starting OD.sub.600 = 0.37) PAN
ASFPAN Cellulose Cellulose_TiO.sub.2 CA CA_TiO.sub.2 Carbon Control
0.50 1.54 1.4 1.61 0.91 1.98 2.0 2.2
TABLE-US-00003 TABLE 3 OD.sub.600 of SK1 strain after 18 hr contact
with electrospun nanofibrous mats (starting OD.sub.600 = 0.04) PAN
ASFPAN Cellulose Cellulose_TiO.sub.2 CA CA_TiO.sub.2 Carbon Control
0 0.12 0.2 0.36 0.026 0.14 0.44 0.30
Example 3
Effect of Nanofiber Mat on SK1 and W303 Cell Growth Via SEM
[0089] To confirm that the antifungal activity of nanofibrous PAN
was not unique to SK1, but instead representative of a broader
class of fungal cells, the growth of SK1 and W303, a S. cerevisiae
yeast strain, was compared via scanning electron microscopy.
[0090] Nanofibrous PAN mats were cut into 6 mm.times.4 mm pieces
and glued individually to glass chips. The glass chips were then
glued onto petri dishes. Cultures of SK1 and W303 strains were
transferred into corresponding petri dishes. After 30 minutes of
contact, the nanofibrous samples were rinsed softly with DI water
and immersed in a fixing solution. The samples were then removed
from solution after overnight immersion and left to dry. The
samples were evaluated using SEM imaging. Both SK1 and W303 cells
flattened and lost their vitality after 30 min contact with the
surface of nanofibrous PAN (FIGS. 3A and 3B).
Example 4
[0091] Effect of PAN and CA Nanofibers on the Growth of Fungal
Cells, SK1 and C. albicans
[0092] Fungal cells, SK1 and C. albicans, were cultured on YPD and
SBD solid agar plates, respectively, for 48 hrs in an incubator at
30.degree. C. and stored in a refrigerator for 3 days. Different
mass of substrates including 25 mg, 20 mg, 15 mg, 10 mg and 5 mg of
each of CA nanofibrous mat, PAN nanofibrous mat, cellulose
nanofibrous mat, CA film, PAN film, cellulose film were added to
individual 50 mL glass flasks. 10 ml YPD and SBD liquid media were
added to the corresponding 50 mL glass flasks for SK1 and C.
albicans, respectively. One 5-day-old single colony of either SK1
and C. albicans was selected from the relevant solid agar plate and
added to the respective flasks. The flasks were then placed in a
shaking incubator (130 rpm) at 25.degree. C. for 16 hours. Optical
densities (OD.sub.600) were measured afterwards by a Thermo
Scientific NANODROP.TM. 2000C spectrophotometer.
[0093] The OD.sub.600 results (FIG. 7) clearly showed that
electrospun nanofiber mats including CA, cellulose and PAN have
differing inhibition effects on the growth of SK1 and C. albicans.
Particularly PAN and CA nanofibrous mats showed much stronger
inhibition effect than cellulose nanofibrous mat. For SK1 cells,
the CA nanofibrous mat had a more significant inhibition effect
than that of the PAN nanofibrous mat. For C. albicans, the PAN
nanofibrous mat had a more significant inhibition effect than the
CA nanofibrous mat. The control substrates, and cast films of CA,
cellulose and PAN didn't show an inhibition effect. Instead, the
films appeared to promote fungal cell growth. As the mass of the
nanofibrous mat increased, its inhibition affect generally
increased correspondingly.
[0094] It will be understood that various details of the presently
disclosed subject matter may be changed without departing from the
scope of the presently disclosed subject matter. Furthermore, the
foregoing description is for the purpose of illustration only, and
not for the purpose of limitation.
* * * * *