Preparation Of Polysaccharide-?-polylysine Nanofiber Mats And Their Performance As Antibacterial Wound Dressings

With the aging of the global population and the increase of chronic diseases,the incidence of chronic skin trauma has increased significantly.Chronic skin wounds cannot heal for a long time and are extremely vulnerable to bacterial infection.Therefore,the use of antibacterial wound dressings to prevent and control bacterial infections has become an important aspect of wound management.At present,the antibacterial dressings mainly use highly toxic silver ions as antibacterial active ingredients,which are likely to cause various adverse reactions such as silver poisoning,silver allergy,and liver damage.The purpose of this study is to develop an antimicrobial wound dressing with higher safety by covalently loading the antimicrobial peptide?-polylysine from natural organisms with good antimicrobial performance and biocompatibility on the electrospinning polysaccharide nanofiber mats.The detailed work and results are as follows:The first part of the work is to prepare starch-?-polylysine nanofiber(Starch-EPL)by the method of"periodate oxidation-electrospinning-?-polylysine crosslinking",characterize its physical and chemical structure,evaluate its properties of absorbency,permeability,mechanical strength,water resistance,compatibility and other properties related to medical dressings.It was found that Starch-EPL nanofiber mat has a smooth and porous surface with an average diameter of 390 nm,which can load 19.2%of?-polylysine.Its ultimate tensile strength is 0.34 MPa and the elongation is 62.0%.The inner fiber can absorb 2.7 times of its own weight in simulated wound exudate,the antibacterial activity against Escherichia coli is 92.5%and the survival rate of L929 fibroblasts in their extracts is above 82%.While the ultimate tensile strength of the silver-containing dressing is 0.14 MPa and the elongation is27.4%.The inner fiber can absorb 1.7 times of its own weight in simulated wound exudate,the antibacterial activity is 83.7%and the survival rate of L929 fibroblasts is only 65%.Both nanofiber mats have equivalent permeability[0.24 g/(cm~2·24h),0.23 g/(cm~2·24h)],absorbency(12.4 times,14.1 times),broad-spectrum antibacterial property and long-lasting(14 days)antibacterial activity.Therefore,Starch-EPL nanofiber mat is a kind of wound dressing with excellent antibacterial properties and better biocompatibility.In the second part,we prepared polysaccharide?-polylysine nanofiber mats by using hyaluronic acid instead of starch(OHA-EPL)in the same way,characterized its physical and chemical structure,evaluate its properties of absorbency,permeability,mechanical strength,water resistance,compatibility and other properties.Results show that compared with Starch-EPL nanofibers,OHA-EPL nanofiber mats have similar excellent permeability,antibacterial property and biocompatibility,while the content of EPL increases to 27.9%,the tensile strength of mats rises to 0.59 MPa,the elongation grows to 130%and OHA-EPL nanofiber mats can absorb up to 26.3-times exudate.Combined with the excellent biological activity of hyaluronic acid,OHA-EPL nanofiber mats may achieve better therapeutic effects.In summary,we prepared polysaccharide-?-polylysine nanofiber mats by the method of"periodate oxidation-electrospinning-?-polylysine crosslinking",which not only achieved excellent antibacterial properties,but also obtained better biocompatibility than traditional silver-containing dressings,thus solving the biotoxicity problem of antibacterial dressings.Through material optimization,the performance of permeability,absorbency,mechanical properties and wettability were further improved,which laid a foundation for the application of polysaccharide-?-polylysine nanofiber mats in wound dressing.