Characterization Of Electro-active And Antibacterial Dressing Prepared By Megnetron Sputtering

Medical dressings are protective materials used to promote wound healing.Studies have shown that bacterial infection is the main cause of healing delay and even death.Therefore,it is necessary to functionalize materials against bacteria.In addition,polymer materials with special structure and properties have attracted many views in the field of medical dressings.They not only have appropriate antibacterial activity,but also are more suitable for medical dressing after special processing technology.Although several dressings have been developed to accelerate wound healing,these dressings still lack the ability to actively stimulate the migration of skin cells(epithelial cells,fibroblasts,stem cells,and other skin-related cells)to accelerate wound healing.Therefore,it is of great significance to study an electroactive antibacterial dressing that combines electrical stimulation with wound dressing to promote the wound healing.This paper focuses on constructing the Ag/Zn microbattery on the surface of micron-and nano-scale fibers by magnetron sputtering technology to develop an electroactive antibacterial dressing.(1)Three kinds of functional wound dressings(Zn@Cotton,Ag@Cotton and Ag/Zn@Cotton)were prepared by template-assisted magnetron sputtering of cotton nonwovens.SEM and EDS revealed a very thin,uniform silver oxides and zinc coating on the cotton cellulose microfibers,which was further confirmed by XRD,XPS,and TGA.The physical characteristics such as high swelling ability,moderate air and water vapor permeabilities,good mechanical properties,and excellent flexibility support the suitability of magnetron sputtering cotton nonwovens for wound dressing applications.Moreover,the Ag/Zn@Cotton showed effective antibacterial activities against Escherichia coli and Staphylococcus aureus,which was mainly attributed to the synergistic effect of electrical stimulation and continuous release of Ag⁺/Zn²⁺.Meanwhile,benefiting from the low proportion of metal electrodes(only 17.54%of the whole dressing),the Ag/Zn@Cotton had no effect on the proliferation and differentiation of human embryonic fibroblasts and exhibited good cytocompatibility.The in vitro and in vivo test showed that Ag/Zn@Cotton can remarkably accelerate the wound healing rate,which can be attributed to the enhanced cellular migration by electrical stimulation,strong antibacterial activity,good cytocompatibility,and excellent physical-chemical properties.(2)Three kinds of functional wound dressings(Zn@Cotton,Ag@Cotton and Ag/Zn@Cotton)were prepared by template-assisted magnetron sputtering of PCL/Gel nanofiber films by electrospinning technique.It was found that Ag/Zn@PCL/Gel dressing showed good swelling and air permeability.And the dressing could produce continuous current and voltage(voltage up to 851 m V,current up to 37?A)in saline solution.At the same time,with the help of numerical simulation software COMSOL MULTIPHYSICS,we found that these electrode units can produce an electric field of 1 k V/m,so it can promote wound healing rate by promoting the proliferation and migration of fibroblasts.Qualitative/quantitative antibacterial experiment and intracellular reactive oxygen species(ROS)levels expounded that the excellent antimicrobial properties of the dressing is due to,on the one hand,a rapid release of metal ions,on the other hand,electrical stimulation to promote intracellular reactive oxygen species(ROS)levels increased,which accelerates oxidative stress reaction in the cell,and then destroys the membrane structure and protein.Therefore,the synergistic antibacterial effect of ROS and metal ions makes it have excellent antibacterial properties.In addition,pathological analysis showed that the electroactive antibacterial dressing with nano-fibers could effectively promote wound healing rate,and no structural damage or tissue lesions were observed in the main organs of mice(heart,liver,spleen,lung and kidney)after 13 days surgery,which confirmed the good biological safety of the functional dressing.In summary,we prepared two kinds of electroactive antibacterial dressings and studied their role in promoting wound healing.The experimental results showed that both the Ag/Zn@Cotton dressing and Ag/Zn@PCL/Gel dressing have a good effect on promoting wound healing,which have good application potential in wound healing.