Page 301 - Biodegradable Polyesters

11.2 Simply Blended Drug/Biopolymer Nanofibers 279

of 100% and riboflavin to an extent of 40% within 60 s) from PVA nanofibrous
matrices [27]. Hydrogels are of interest in the biomedical field owing to their
potential application in drug delivery devices as well as in wound dressing. Fogaca
et al. described the production of a novel poly(N-vinyl-2-pyrrolidone) (PVP)
hydrogel membrane produced by electrospinning with a gel fraction up to 90%
and a high swelling degree. Electrospun PVP nanofibers, cross-linking with UV-C
radiation, and Fenton reactions were used to obtain a highly porous membrane.
Collagenase release behavior and its enzymatic activity were evaluated in order
to estimate the ability of this biomaterial to be used as an enzymatic debriding
wound dressing [28].

11.2.2
Drug-Loaded Multicomponent Biopolymer Nanofibers

As summarized above, electrospun nanofiber membranes of drug-loaded
single-component biopolymers, especially natural biopolymers such as chitosan,
collagen, and gelatin, usually show poor mechanical property for long-time drug
release durations, supporting cell cultures, and wound dressings [29]. Therefore,
composites of synthetic polymer/natural biopolymers such as poly(ethylene
oxide) (PEO)/chitosan [30, 31] and PVA/gelatin [32, 33] were consecutively
developed. However, water-soluble polymers, such as PEO and PVA, always
suffer from problems of easy dissolving and gel forming in the aqueous solution,
which not only sharply decreases the mechanical properties but also leads to
large initial burst release of drugs. Hence, aliphatic polyesters with hydrophobic
property, such as PCL, PLA, and poly(glycolic acid) (PGA), were introduced
into water-soluble polymers to form composite nanofibers with both excellent
biocompatibility and mechanical property [34, 35].
In Meng’s study, both aligned and randomly oriented PLGA/chitosan nanofi-
brous scaffold with smooth surface have been prepared by electrospinning.
The drug release rate increased with the increase of chitosan content because
the addition of chitosan enhanced the hydrophilicity of the PLGA/chitosan
composite scaffold. Moreover, the drug release rate from aligned PLGA/
chitosan nanofibrous scaffold was lower than that from randomly oriented
PLGA/chitosan nanofibrous scaffold, which was influenced by the nanofiber
arrangement. In addition, cross-linking in glutaraldehyde vapor effectively
decreased the burst release of fenbufen (FBF), making PLGA/chitosan composite
scaffold promising for future applications in biomedicine [36]. Similarly, they
reported FBF-loaded PLGA/gelatin nanofibrous scaffolds fabricated via electro-
spinning technique, which can easily realize controlled drug release by tuning
gelatin content, fiber arrangement, cross-linking time, and pH value of the buffer
solution, as shown in Figure 11.3 [37]. Park et al. [38] also electrospun PGA/chitin
composite nanofibers with 1,1,1,3,3,3-hexafluoro-2-propanol as solvent. Their
study showed that PGA/chitin (25/75) with BSA coating has an excellent cell
attachment and spreading for normal human fibroblasts, which would be a good
candidate for tissue engineering scaffold.