Preparation Of OSA-ZnO Composite Nanofibers Loaded With Zinc Oxide And Its Application In Rat Skin Wound Healing

For the increasingly complex wounds in modern society,a variety of new medical dressings continue to emerge,and the requirements for dressings are getting higher and higher.For example,dressings should have the ability to guide or regulate cell migration and tissue regeneration,have good biocompatibility and excellent antibacterial properties,so that dressings can play an important role in the early and late repair of wounds.The structure of nanofibers prepared by electrospinning technology can mimic the extracellular matrix(ECM)well,and it also has the characteristics of high specific surface area,controllable morphology and high drug loading rate,which is conducive to cell migration and growth Proliferation and promote wound healing.Therefore,electrospinning technology is chosen to prepare new medical dressings.In this topic,we choose Sodium Alginate(SA)in the commercialized alginic acid dressing as the base material,and perform oxidative ring-opening reaction to prepare Oxidized Sodium Alginate(OSA).Zinc oxide nanoparticles(Zn O-NPs)were loaded on OSA nanofibers by blending electrospinning technology to prepare OSA-Zn O composite nanofiber membranes with different zinc oxide content.We have carried out basic physical and chemical analysis of OSA through Fourier Infrared Spectroscopy(FTIR),~1H-NMR,Thermo Gravimetric Analyzer(TGA)and Oxidation Titration,using Scanning Electron Microscope(SEM),mechanical properties test,nanofiber membrane degradation test,Energy Dispersive Spectroscopy(EDS),X-ray Diffraction(XRD),TGA and other experiments to characterize the physical and chemical properties of composite nanofiber membranes such as morphology,composition,thermal stability,and mechanical properties.The results of oxidation titration showed that there was a linear relationship between the degree of oxidation of OSA and the amount of oxidant;SEM observed that the surface of the prepared nanofibers was smooth,and there was a certain relationship between the average fiber diameter,the degree of oxidation of OSA and the crosslinking concentration;Degradation experiments show that the degradation rate of OSA nanofiber membranes can be adjusted by adjusting the concentration of crosslinking agent;SEM,EDS and XRD experiment results show that OSA-Zn O composite nanofiber membranes have been successfully prepared,and the addition of zinc oxide has no effect on the surface morphology of the fiber membranes;TGA results show that nano-zinc oxide has no significant effect on the thermal stability of the composite fiber membrane;The addition of a certain amount of Zn O-NPs on the mechanical test surface can significantly enhance the mechanical properties of the OSA-Zn O composite nanofiber membrane.The biological performance of the composite nanofiber membrane was comprehensively evaluated by studying the in vitro biocompatibility,antibacterial performance and in vivo wound repair experiments of the OSA-Zn O composite nanofiber membrane.The mouse fibroblasts(NIH-3T3)and Human Umbilical Vein Endothelial Cells(HUVECs)were co-cultured with the material,and the proliferation and adhesion of the cells were observed and analyzed.It was found that the sensitivity of different cells to the material was different,and with the membrane with the increase of Zn O-NPs content,the cell activity showed a decrease behavior.The results show that high concentrations of zinc oxide have certain cytotoxicity;The antibacterial effect of the OSA-Zn O composite nanofiber membrane was evaluated for the antibacterial experiment in vitro,and the fiber membrane showed strong antibacterial ability.Bacterial SEM showed that high concentration of Zn O-NPs had a greater influence on the morphology of bacteria;Finally,the wound healing ability of OSA-Zn O composite nanofiber membrane was studied by constructing a rat skin wound repair model,and the results showed that composite nanofiber membrane can obviously promote wound healing in rats.The results of immunohistochemistry and immunofluorescence found that the composite nanofiber membrane can accelerate angiogenesis and induce the polarization of macrophages to the M2 direction,and promote the regeneration of wound granulation tissue and the deposition of collagen,so as to accelerate wound healing.In summary,the OSA-Zn O composite nanofiber membrane prepared in this experiment has both good biocompatibility and excellent antibacterial properties.At the same time,the elemental zinc and nanofiber structure have a common effect on cells,growth factors and tissues.The regulating effect achieves the purpose of accelerating wound healing.Therefore,we believe that the OSA-Zn O composite nanofiber membrane as a new type of medical dressing has greater application value in the field of accelerating wound healing and guiding skin tissue regeneration.