Study On Antibacterial Wound Dressing Of Nanofiber Based On Electrospinning Technology

In the course of clinical treatment,the management of acute and chronic infectious wounds is a very challenging problem.The main factors hindering wound healing include malnutrition,diseases(such as arteriosclerosis,diabetes,lymphedema)and bacterial infection.bacterial infection is an important factor among many factors hindering wound healing,and with the abuse of antibiotics and the continuous emergence of drug-resistant bacteria,the development of a topical wound dressing with broad spectrum sterilization is an urgent problem to be solved in clinical medical work.Compared with commonly used gauze dressings,nanofiber dressings have the advantages of smaller size and less secondary wound damage,but the nanofibers obtained by self-assembly and template synthesis have the disadvantages of complicated process and expensive price,so they are not suitable for widespread promotion in clinical treatment.electrospinning is an effective method to prepare continuous nanofibers,and the resulting nanofiber membranes have high porosity,high specific surface area,good gas exchange,good liquid absorption and other properties,which is expected to be applied in the field of wound dressings.In this paper,on the basis of analyzing the bactericidal mechanism of commonly used clinical antibacterial disinfectants Polyvinylpyrrolidone iodine(PVP-I)and benzalkonium bromide,three kinds of nano-fiber antibacterial wound dressings with excellent antibacterial effect,good biocompatibility and low price were prepared by electrospinning technology,and good results were obtained.It provides an effective method to solve the problems of acute infectious wounds and chronic infectious wounds,which has certain clinical application value.This paper mainly includes the following three parts:1.Aiming at the problems such as strong water solubility,many complications and easy wound residue after long-term use of benzalkonium bromide,a quaternary ammonium poly(4-vinylpyridine)(P4VP)antibacterial nanofiber dressing was prepared by electrospinning and fiber surface modification technology.Firstly,P4VP nanofiber membrane was prepared by electrospinning.After optimizing spinning conditions,the diameter of nanofiber was optimized to 330nm.Then 1,4-p-dichlorobenyl was added to induce P4VP crosslinking,and some quaternary ammonium salts were introduced.The crosslinked nanofiber film was then subjected to quaternary ammonium reaction with benzyl bromide,bromoethane,bromobutane,bromohexane,bromooctane,bromodecane,bromododecane,bromotetradecane and bromohexadecane respectively,and finally the quaternized P4VP nanofiber dressing was obtained.The results showed that P4VP nanofibers had the best antibacterial performance.The absorbance of the supernatant of Escherichia coli and Staphylococcus aureus treated with P4VP nanofibers was 20.41 times and 188.71 times that of the gauze group,respectively,showing excellent broad-spectrum antibacterial performance.Biocompatibility results showed that the cytotoxicity of this type of fiber was relatively high,and the statistical difference was significant(P<0.0001).Although it is difficult to be used as antibacterial disinfection materials for open wounds,it has potential application value in medical devices and other fields.In order to solve the problem of poor biocompatibility of quaternary ammonium nanofibers,we designed and manufactured a new nanofiber antibacterial wound dressing based on the bactericidal mechanism of PVP-I,another commonly used disinfectant in clinical practice.2.In order to solve the problem that polyvinylpyrrolidone iodine is highly water-soluble and difficult to form antibacterial fibers,a non-water-soluble,thermally-crosslinked polyvinylpyrrolidone/iodine(PVP-I)nanofiber antibacterial dressing was prepared by electrospinning,thermal crosslinking and fiber modification techniques.Firstly,PVP nanofiber membrane was prepared by electrospinning technology from PVP,and the shortcomings of PVP nanofiber membrane dissolved in water were solved by thermal crosslinking treatment.Then,by reacting with I2,Iodide-loaded crosslinked PVP nanofiber(PVP-I)antibacterial material was obtained,and the complexation equilibrium reaction conditions of I2 and PVP nanofiber were investigated.Through the optimization experiment,it was determined that the crosslinking condition of PVP nanofibers was heated at 170℃ for 6h.When PVP reacted with iodine,the molar ratio of iodine to PVP chain was 7:1.The bacterial and biocompatibility tests showed that the nanofiber dressing had excellent antibacterial properties,and the bactericidal rates against Escherichia coli and Staphylococcus aureus were 34%and 53%,respectively.In addition,the nanofiber dressing has good biocompatibility,and the survival rate of NIH/3T3 cells is as high as 99.1%,and the hemolysis rate of mouse red blood cells is as low as 6.6%.The nanofiber dressing is simple and inexpensive,and is expected to be used as a new alternative to ordinary gauze in clinical treatment.In this work,although the shortcomings of PVP nanofiber membrane dissolved in water were solved by thermal crosslinking method,it was found that the method also had some problems such as fiber brittle and complicated operation caused by thermal crosslinking process.3.In order to solve the problems of decreasing material properties and complex operation of thermal crosslinked PVP-I nanofibers,the water-insoluble poly(methyl methacrylate-vinylpyrrolidone)/iodine nanofiber antibacterial dressing,Poly(MMA-co-NVP)-I nanofibers,was directly prepared by using free radical polymerization,polymer modification and electrospinning techniques.Firstly,insoluble polymer Poly(MMA-co-NVP)was obtained from N-vinylpyrrolidone(NVP)and methyl methacrylate(MMA)through free radical copolymerization,and then reacted with I2 to obtain iodine-modified Poly(MMA-co-NVP)solution,which was used as raw material for spinning.Poly(MMA-co-NVP)-I nanofiber antibacterial material was prepared by electrospinning.It was found that the Poly(MMA-co-NVP)-I nanofibers had a low fiber diameter(average diameter 169.84nm),strong liquid absorption capacity and stability,and the liquid absorption capacity of Poly(MMA-co-NVP)-I nanofibers was 8 times its own weight,and the weight of the Poly(MMA-co-NVP)nanofibers remained 97.33%after 72h of liquid immersion under simulated body fluid conditions.Bacterial and biocompatibility experiments showed that the nanofiber dressing had excellent antibacterial properties,and the bactericidal rates against Escherichia coli and Staphylococcus aureus were 50%and 70%,respectively.The nanofiber dressing has good biocompatibility.When the fiber concentration is 2mg/mL,the cell survival rate is 89.88%,and the hemolysis rate of mouse red blood cells is as low as 2.26%.Through in vivo evaluation,it was found that Poly(MMA-co-NVP)-I nanofibers could significantly reduce the bacterial concentration at the wound site and promote the healing of infected wounds,and the healing rate of wounds in the experimental group was as high as 99.09%on the 15th day.The results of histological and immunohistochemical staining showed that the skin of the wound bandaged by Poly(MMA-co-NVP)-I nanofibers had faster repair,more collagen regeneration,fewer macrophages and weaker inflaMMAtory reaction.The nanofiber dressing has the advantages of simple manufacturing method,strong stability and low price,and is expected to be a new choice to replace ordinary gauze in clinical treatment.In suMMAry,in the work of this paper,we prepared three kinds of antibacterial nanofiber materials based on PVP and P4VP based on electrospinning technology,combined with fiber modification and polymer modification methods,studied their structure and properties,and found that the three kinds of nanofiber dressings have excellent antibacterial properties.In particular,Poly(MMA-co-NVP)-I nanofibers have good properties and simple preparation methods,and are expected to be applied in the field of medical wound dressings.The results of this study provide a new method and a new idea for the development of medical antibacterial wound dressings,and provide a new direction for the management and treatment of acute infectious wounds and chronic infectious wounds.