Synthesis And Characterization Of Electrospun Nanofiber Membranes For Wound Dressing

Open wounds are easily invaded by bacteria.Bacterial infections are the main cause of inhibiting wound healing.The huge demand of wound care markets creates opportunities for the development of antibacterial wound dressings.Based on the aim of developing biomedical wound dressings,we successfully farbricated a series of single-layer and bilayer electrospun membranes using biodegradable polymer polycaprolactone,polyvinyl alcohol and gelatin as matrix materials,dimethyl octadecyltrimethoxysilyl propyl ammonium chloride(QAS)as an antibacterial agent.Electrospun PG-Q membranes with different QAS contents were fabricated.We systematically investigated the properties of the PG-Q membranes.The uniform beads-free continuous nanofiber morphology was observed by SEM and TEM.Hydrophilic test demonstrated that the PCL-gelatin/QAS(PG-Q)nanofiber membranes showed hydrophobic surface property and sufficient water absorption.The physical and chemical cross-linking between QAS/PCL and QAS/gelatin were characterized by FTIR and XPS,which is beneficial for the long-term antibacterial property.Furthermore,the PG-Q nanofiber membranes,especially PG-Q15 and PG-Q20,showed a considerable increase in the bacteriostatic rate towards S.aureus(Gram-positive)and P.aeruginosa(Gram-negative),demonstrating their broad-spectrum bactericidal effect.Additionally,the PG-Q membranes with different QAS content showed no cytotoxicity to mouse fibroblast cells(L929 cells).Therefore,electrospun PG-Q 15 and PG-Q20 membranes have the best comprehensive performances as antibacterial wound dressing.In order to resist the invasion of wounds by pathogens and/or dust,a kind of bilayer PCL/PVA-Q electrospun membranes with isolation and antibacterial function were prepared.The outer layer was highly oriented PCL nanofibers and the inner layer was random PVA-Q nanofibers.The dense hydrophobic outer surface and porous hydrophilicity inner layer were confirmed by SEM and WCA.The biocompatibility and bacteriostasis of PCL/PVA-Q membranes were investigated.The results showed that L929 cells proliferated well on PVA-Q.When QAS content reached 12%,PVA-Q membrane could rapidly kill 90%of Staphylococcus aureus,and the hydrophobic dense outer layer can effectively isolate pathogens and other foreign body as a barrier material.By taking the advantage of biological non-toxic and broad-spectrum antibacterial,bilayer PCL/PVA-Q electrospun membranes are potential candidates for advanced wound dressings.In short,the thesis was aimed at the phenomenon of unhealed wound caused by bacterial infection and carried out research.The basic properties of these new materials were systematically studied.The biocompatibility and antibacterial properties were emphatically investigated.Therefore,electrospinning non-leaching antibacterial nanofiber membranes could be an optimal choice for antibacterial wound.