Study On The Healing Effect Of ZnO/Ag/PVP/PCL Bimetallic Nanofibers On Wound Healing

Wound healing is a complex process including hemostasis,antimicrobial,anti-inflammatory,tissue remodeling and the other processes.Due to the advantages of antibacterial activity,anti-inflammatory and anti-wrinkle properties,promotion of tissue regeneration and so on,ZnONPs had become an ideal nano-material for wound healing.However,a lower concentration of ZnONPs shows the ability to inhibit but does not kill microbes and therefore may develop resistance when exposed to dr ug frequently.It is a contradiction that high concentrations of zinc oxide nanoparticles used would induce intolerance in the body.Therefore,a reliable drug delivery technology that can maintain the superiority of Zn ONPs for wound healing and reduce the dose of administration for drug while not reducing its efficacy on killing bacteria is highly desired.Silver nanoparticle(Ag NPs),another metal materials investigated for a long time,are an alternative antibacterial agent to inhibit/kill bacteria and show a significantly better antibacterial capacity than many antibiotics.Similarly to Zn O,high amount of Ag used would result in serious side effects.More importantly,high amount of Ag nanoparticles used trend to aggregate resulting in decreased stability,which in turn reduce the antibacterial efficacy.Theoretically,in combination therapy based Zn O and Ag,both amount of Zn O and Ag could be reduced without reducing the therapeutic efficacy.Furthermore,the Zn O/Ag bimetallic nanomaterials would centralize all advantages of both drugs and provide a general means to maximize therapeutic efficacy,overcome treatment resistance and reduce adverse effects.In the study,Staphylococcus aureus and Escherichia coli were used as test strains to investigate the antibacterial effect of the single metal nanofibers(including Zn O and Ag nanofibers)and Zn O/Ag bimetallic nanofibers.Human skin fibroblasts were used as test cells to investigate the cytotoxicity of the single metal nanofibers and Zn O/Ag bimetallic nanofibers.The effect of single metal nanofibers and ZnO/Ag bimetallic nanofibers on wound healing was studied by using SD rats as model animals.The research is as follows:The first part of this study mainly describes the status quo of electrospinning nanofibers as wound dressings and the research status of metal nanomaterials on wound healing,and provides theoretical support for this research.In the second part of the study,Zn ONPs were prepared by solution-gel method.And ZnO nanofibers were prepared by electrostatic spinning technology and cross-linked by glutaraldehyde.The prepared nanoparticles and nanofibers were characterized by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The permeability and swelling degree of Zn O nanofibers were investigated.The antibacterial effect on Staphylococcus aureus and the healing ability on wound of Zn O nanofibers were investigated.The results showed that the prepared Zn ONPs were uniformly dispersed in the nanofibers.The nanofibers had a good cross-linking effect and a smooth surface.Zn O nanofibers had better permeability and swelling degree than nonwovens.The results showed that ZnO nanofibers can inhibit Staphylococcus aureus and promote wound healing.The above results show that Zn O nanofibers can combine the advantages of nanoparticles and nanofibers to promote wound healing.In the third part of this study,ZnONPs and AgNPs were prepared respectively.And then Zn O/Ag bimetallic nanofibers were prepared by electrospinning.The prepared nanofibers were characterized by SEM,TEM,IR and differential scanning calorimetry(DSC).The physical and chemical properties of permeability,swelling degree,weight loss rate and release degree of Zn O/Ag bimetallic nanofibers were investigated.The cytotoxicity to human skin fibroblasts and antibacterial effect on Staphylococcus aureus and Escherichia coli of ZnO/Ag bimetallic nanofibers were investigated.The healing effect of ZnO/Ag bimetallic nanofibers on wound healing in SD rats was investigated.The results showed that the particle sizes of Zn ONPs and AgNPs were(40.07±9.70)nm and(37.46±12.02)nm,respectively.The morphology of the prepared nanofibers is relatively smooth.Zn ONPs and AgNPs are physically embedded in the nanofibers.The cytotoxicity of ZnO/Ag bimetallic nanofibers was lower than that of single metal nanofibers at a lower dose.The antibacterial effect of ZnO/Ag bimetallic nanofibers on Staphylococcus aureus and Escherichia coli is superior to that of single metal nanofibers.In vivo test showed that ZnO/Ag bimetallic nanofibers could synergistically promote wound healing.The above results indicated that Zn O/Ag bimetallic nanofibers had synergistic effects on wound healing.The study first confirmed that Zn O nanofibers have the ability to inhibit the growth of microorganism and promote wound healing.Next,in order to improve the antibacterial activity and the healing ability of the prepared nanofibers,AgNPs and Zn ONPs were combined to form ZnO/Ag bimetallic nanometer preparation by electrospinning.And the antibacterial effect and healing ability of the bimetallic nanofibers and single metal nanofibers were compared.The results demonstrated that ZnO/Ag bimetallic nanofibers had better antibacterial and wound healing ability,and had the ability to develop new wound healing agent.