Illustration showing the fabrication process and test contents of electrospun gelatin nanofibers loaded with vitamins A and E as wound dressing materials in this paper.

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To obtain wound dressings which could be removed easily without secondary injuries, we prepared thermoresponsive electrospun fiber mats containing poly(di(ethylene glycol) methyl ether methacrylate) (PDEGMA). Blend fibers of PDEGMA and poly(l-lactic acid-co-ε-caprolactone) (P(LLA-CL) were fabricated via electrospinning, and analogous fibers containing the antibiotic ciprofloxacin (CIF) were also prepared. Smooth cylindrical fibers were obtained, albeit with a small amount of beading visible for the ciprofloxacin-loaded fibers. X-ray diffraction showed the drug to exist in the amorphous physical form post-electrospinning. The composite fibers showed distinct thermosensitive properties and gave sustained release of CIF over more than 160h in vitro. The fibers could promote the proliferation of fibroblasts, and by varying the temperature cells could easily be attached to and detached from the fibers. Antibacterial tests demonstrated that fibers loaded with ciprofloxacin were effective in inhibiting the growth of E. coli and S. aureus. In vivo investigations on rats indicated that the composite PDEGMA/P(LLA-CL) fibers loaded with CIF had much more potent wound healing properties than a commercial gauze and CIF-loaded fibers made solely of P(LLA-CL). These results demonstrate the potential of PDEGMA/P(LLA-CL)/ciprofloxacin fibers as advanced wound dressing materials.

In this work, we aimed to develop new materials to reduce the secondary injuries which can be imparted when replacing wound dressings. Electrospun fibers based on the thermoresponsive polymer poly(N-isopropylacrylamide) (PNIPAAm), poly(l-lactic acid-co-ɛ-caprolactone) (PLCL), and the antibiotic ciprofloxacin (CIF) were prepared. The water contact angle of fibers made from a blend of PNIPAAm and PLCL changed dramatically when the temperature was increased above 32°C. Sustained release of CIF from the formulations was observed over >200h. Moreover, L929 fibroblasts could proliferate on the fibers, indicating their biocompatibility. The CIF-loaded fibers were found to have potent antibacterial activity against E. coli and S. aureus. In vivo tests on rats indicated that CIF-loaded thermosensitive fibers have enhanced healing performance compared to CIF-loaded PLCL fibers or a commercial gauze. Electrospun PNIPAAm/PLCL fibers loaded with CIF thus have great promise in the development of new wound dressing materials.

Poly N-vinylcaprolactam-co-acrylamidophenylboronic acid p(NVCL-co-AAPBA) was prepared from N-vinylcaprolactam (NVCL) and 3-acrylamidophenylboronic acid (AAPBA), using 2,2-azobisisobutyronitrile (AIBN) as initiator. The synthesis and structure of the polymer were examined by Fourier Transform infrared spectroscopy (FT-IR) and (1)H-NMR. Dynamic light scattering (DLS), lower critical solution temperature (LCST) and transmission electron microscopy (TEM) were utilized to characterize the nanoparticles, CD spectroscopy was used to determine if there were any changes to the conformation of the insulin, and cell and animal toxicity were also investigated. The prepared nanoparticles were found to be monodisperse submicron particles and were glucose- and temperature-sensitive. In addition, the nanoparticles have good insulin-loading characteristics, do not affect the conformation of the insulin and show low-toxicity to cells and animals. These p(NVCL-co-AAPBA) nanoparticles may have some value for insulin or other hypoglycemic protein delivery.

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Thioridazine (TDZ), originally an anti-psychotic drug, suppresses several types of cancer and has specificity for leukemia stem cells. The present study was performed to assess its effect on lung cancer stem-like cells, as its effect remains unknown. TDZ was utilized to treat lung cancer stem-like cells (A549 sphere cells) and its cytotoxic effect and mechanism were evaluated in vitro and in vivo. TDZ elicited cytotoxicity in A549 sphere cells and inhibited their proliferation in a dose-dependent pattern. A549 sphere cells treated with TDZ showed nuclear fragmentation, increased G0/G1 phase distribution, positive Annexin V staining, and a change in the expression of caspase family and cell cycle-associated proteins. These results suggest the induction of caspase-dependent apoptosis and cell cycle arrest. In addition, TDZ treatment resulted in significant inhibitory effect on mice xenografts established by A549 sphere cells. TDZ repressed growth of lung cancer stem-like cells in vitro and in vivo, indicating its potential application in targeting lung cancer stem-like cells.

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