| Wound healing is the recovery process of the broken or defected skin tissue plagued by external force. Using wound healing materials can accelerate the process, which can be applied in a wide range, such as trauma, burns and skin ulcers. The wound healing materials not only can cover the wound surface to prevent bleeding and infection, but also can promote wound healing, create "clean cut area" steadily, absorb the bacteria and fluid. It could provide a moist wound microenvironment system in order to accelerate the wound healing process. The electrospun drug-loaded composite nanofibers have the characteristics of nanometer fiber structure, pore structure and versatility, which makes it become a hot spot of wound healing materials in recent years.In this paper, good biocompatible polymer poly (vinyl alcohol, PVA)-Stilbazole Quaternized (SbQ) and natural protein zein were chosen as the backing materials. PVA-SbQ/zein composite nanofibers blend with different mass ratios were fabricated by electrospinning. The surface morphologies and diameter distributions, structures and mechanical properties of the nanofibers were characterized to select the superior composite nanofibers as the base drug-loaded material. Results showed that the proportion of 1:1 composite nanofiber had smooth surface without the bead and had an optimal tensile strength. FTIR showed that hydrogen bonding was formed betweent PVA-SbQ and zein, which could verify the successful blending. The ratio of PVA-SbQ/zein (1:1) was selected as the optimized one after comprehensive consideration.On the basis of PVA-SbQ/zein composite nanofibers, hydrophilic tetracycline hydrochloride (TCH) drug and hydrophobic vaccarin drug were loaded in the nanofibers using co-electrospun method. And TCH-loaded nanofibers were also prepared using coaxial electrospinning. The drug release of two TCH-loaded nanofiers was compared and the surface morphologies and thermal properties were characterized. Results showed that vaccarin-loaded nanofibers appeared swelling phenomenon with an average diameter of 378±71 nm. TCH-loaded nanofibers had a smooth structure with an average diameter of 765±21nm. The coaxial electrospun TCH-loaded nanofibers showed a clear core-sheath structure.FTIR analysis showed the good compatibility among PVA-SbQ, zein and drug, and the molecular inter-atomic forces, such as electrostatic adsorption, hydrogen bonding and hydrophobic interaction could increase the compatibility between them, which is beneficial to be as wound dressing materials. XRD test showed that PVA-SbQ, zein and TCH had a good dispersion performance in the core-sheath nanofibers. Mechanic tests showed that the tensile strength of coaxial electrospun nanofibers was better than the co-electrospun nanofibers. Drug release results showed that the release behavior of coaxial drug-loaded nanofibers followed the Fickian diffusion mechanism, but the co-electrospun nanofibers did not follow.Finally, biocompatibility of PVA-SbQ/zein nanofibers with drug and without drug was evaluated. Vaccarrin-loaded PVA-SbQ/zein nanofibers as the backing material, combined with comfortable cotton as the wound healing material. The wound healing performance was examined in vivo by rat skin models and histological observations. Results showed that PVA-SbQ/zein nanofibers with drug and without drug showed non-toxic to L929 cells. Wound treated with nanofibers combined with cotton showed better wound healing performance than gauze group. |
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