Page 303 - Biodegradable Polyesters

11.2 Simply Blended Drug/Biopolymer Nanofibers 281
3+
bioactive europium-doped hydroxyapatite (HAp:Eu ) nanofibers and microbelts
have been prepared by combination of sol–gel and electrospinning processes
with a cationic surfactant as template. The red luminescence emission intensity
of Eu 3+ in the drug carrier system varies with the released amount of ibuprofen
(IBU), thus the drug release process can be easily tracked and monitored by the
change in luminescence intensity [42]. Similarly, up-conversion luminescent and
3+ 3+
porous NaYF :Yb ,Er @SiO nanocomposite fibers are prepared by electro-
2
4
spinning process with doxorubicin hydrochloride (DOX) as a typical anticancer
drug. The biocompatibility test on L929 fibroblast cells reveals low cytotoxicity of
3+
3+
the fibers. The release of DOX from NaYF :Yb ,Er @SiO exhibits sustained,
4 2
pH-sensitive release patterns with similar cytotoxicity as the free DOX on HeLa
cells. Furthermore, the fibers show near-infrared Up-conversion luminescence
and are successfully applied in bioimaging of HeLa cells [43].
Co-delivery of several drugs has been regarded as an alternative strategy
for achieving enhanced therapeutic effect. Mesoporous silica nanoparticles
(MSNs) were chosen to load a hydrophobic model drug fluorescein (FLU) and
hydrophilic model drug rhodamine B (RHB), respectively. Then, a co-delivery
system based on electrospun PLGA/MSNs composite membrane was carried out
for co-encapsulation and simultaneously prolonged release of the hydrophilic
and hydrophobic drugs. The results showed that both model drugs of RHB and
FLU maintained a sustained delivery with controllable release kinetics during
the releasing period, which may be used for wound dressings that requires the
combined therapy of several kinds of drugs [44].
With the development of materials and nanotechnology, polymeric nanocom-
posite drug delivery systems (or targeted nanocarriers) are widely studied because
of their unique advantages in tumor diagnostics and therapeutics. In particular,
magnetic micro- and nanoparticles are currently recognized as one of the most
promising modalities of such carriers. Magnetic polymer nanofibers of two cel-
lulose derivatives, dehydroxypropyl methyl cellulose phthalate and CA incorpo-
rated with magnetite (Fe O ) nanoparticles, have been designed and fabricated
3 4
by electrospinning for drug delivery. The feasibility of controlled drug release to
a target area of treatment under the guidance of an external magnetic field has
been demonstrated, showing the viability of the concept of magnetic drug-loaded
polymeric composite nanofibres for magneto-chemotherapy [45].
An electro-sensitive transdermal drug delivery system containing multiwalled
carbon nanotubes (MWCNTs) was prepared by electrospinning method to con-
trol drug release. A semi-interpenetrating polymer nanofiber network consisting
of PEO and pentaerythritol triacrylate was prepared as the matrix, with MWCNTs
used as an additive to increase the electrical sensitivity. Attributed to the excellent
electrical conductivity of MWCNTs, the amount of released drug was effectively
increased with higher applied electric voltages (Figure 11.4) [46]. PCL/MWCNTs
composite nanofibers with various contents of green tea polyphenols (GTPs) were
successfully fabricated via an electrospinning technology to maintain the chemical