Fabrication And Characterization Of Electrospun Peuu Elastomer And Gelatin Composites

The 30 s of the last century after the discovery of penicillin,a large number of antibiotics and antibacterial agent by scientists invented successfully and widely used soon.However,with the abuse of broad-spectrum antibiotics,the drug resistance of bacteria arose.The resistance can be related to the intrinsic characteristics of the strains,or induced by drug through mutation or gene transfer.Microorganism are constantly evolution and mutation with resistance,so researchers need to constantly develop high efficiency,low toxicity antimicrobial agent in order to deal with increasingly serious bacterial and fungal infections.In previous work,we designed a novel chlorinating reagent,N-chloro-N-fluorobenzenesulfonylamide（CFBSA）,which had characteristics such as simple structure,high reactivity,easy availability,wide substrate range and stable storage and exhibited potential antibacterial activity.Different from chloramine B,CFBSA has N-F bond on molecular,which may contribute to decrease cytotoxicity and improve antimicrobial activity.On this basis,the properties of CFBSA such as antimicrobial activity,cytotoxicity and mechanisms were studied further.A better understanding of antibacterial mechanisms contributes to make better understanding of the drug before using this new antibiotic.In this study,we discussed the antimicrobial activity,cytotoxicity and mechanism of CFBSA against different strains.Firstly,κ-B disk diffusion test was used to test the bacteriostatic effect of different nitrogen-fluoride compounds and positive control drugs on different strains,and the bacteriostatic rates were calculated to preliminarily analyze the antimicrobial activity of nitrogen-fluoride compounds.Then,the MIC₈₀values of different nitrogen-fluoride compounds and control drugs for different strains were examined by micro broth dilution method.Then MBC values of different nitrogen fluoride compounds and positive control drugs were detected by broth dilution method and spread plate method,and the bactericidal efficacy was analyzed and compared.Compared with commonly used antimicrobial agents（sulfadiazine and fluconazole）,CFBSA has better antimicrobial effect because of its strong broad-spectrum bactericidal effect.In vitro cytotoxicity test showed that CFBSA had low cytotoxicity,IC₅₀was 514.3±33.6 ug/m L.Then the oxidative stress level of CFBSA in bacteria and fungi was observed and detected by morphology.It was found that CFBSA mainly acted on the cell membrane of bacteria and fungi,and could cause oxidative damage to bacteria/fungi to achieve bacteriostasis and bactericidal effect.Because CFBSA has good bacteriostasis and bactericidal effect,a kind of antimicrobial dressing was prepared by loading CFBSA on P（LLA-CL）/SF fibrous membranes by blend electronspinning.TEM images showed that CFBSA was evenly distributed in P（LLA-CL）/SF fibers and could be kept stable.The diameter distribution of P（LLA-CL）/SF nanofibers loaded with CFBSA at different concentrations were different.The water contact angle of drug-loaded nanofibrous mats changed with the increase of CFBSA content.It was found that CFBSA dramatically increased the hydrophilicity of drug-loaded nanofibers.When the proportion of CFBSA in the spinning solution was high enough,the CFBSA-loaded nanofibers（SP-10）showed hydrophobic again.In vitro antimicrobial tests showed that all CFBSA-loaded P（LLA-CL）/SF fibrous membranes had good antimicrobial activity.Drug-loaded nanofibrous membranes SP-2.5,SP-5 and SP-10 had significant antimicrobial activities against Staphylococcus aureus,Escherichia coli and Candida albicans.When the proportion of CFBSA-loaded P（LLA-CL）/SF nanofibers in the spinning solution was less than 2.5%（v/v）,there was no significant cytotoxicity to L929 cells.In order to balance the biocompatibility and antimicrobial effect,SP-2.5 can be chosen as the ideal loading concentration when CFBSA is further applied in wound dressing.