Research On Preparation And Performance Of Chitosan Wound Dressing

Medical wound dressing is a kind of medical material which covers the wound to both promote wound healing and protect the wound.The traditional gause dressings have shortcomings of serious adhesion,bacterial infection and single performance.Thus,novel wound dressings are evolved considering materials choice and morphology design.Chitosan not only has outstanding pharmacological properties,such as biocompatibility,antibacterial activity,and anti-adhesion property,but also can form a variety of morphologies(membrane,sponge,hydrogel)by physical or chemical crosslinking due to its physical and chemical properties.Therefore,chitosan has a good application prospect in the field of biological materials.However,mebranes,sponges and hydrogels made from chitosan still have some defects.For example,during the preparation of membranes and sponges,acetic acid is used as solvent,thus alkali washing and a second drying are needed to prevent dissolution of chitosan.This process will lengthen preparation period,cause the loss of the additive and even lead to the collapse of products.During the preparation of sponges and hydrogel,the use of common crosslinker like glutaraldehyde will lead to certain cytotoxicity.Therefore,the aim of this study is to prepare three dressings with different morphologies using chitosan as raw materials and evaluate their properties,so as to provide references for clinical application.The preparation parts are as follows:(1)Preparation of precursors:Chitosan flocculence was obtained by acid-base titration;Oxide carboxymethyl cellulose(OCMC)was obtained by redox of carboxymethyl cellulose using sodium periodate.(2)Preparation of chitosan membranes:Chitosan membrane was prepared by casting-evaporation method using chitosan flocculence.(3)Preparation of chitosan hydrogel/Loofah sponge compound:By immersing loofah sponge in a mixed solution of carboxymethyl chitosan and OCMC,a compound was formed with a nested network structure.Effects of additive on the properties of dressings were investigated.Antibacterial and cytotoxicity properties were evaluated based on the optimum parameters.The results are as follows:(1)For chitosan membrane,after adding 0.5%glycerol,the membrae has an increased elongation at break indicating good plasticity.It has good hydrophilicity,permeability and water absorption ability.Slow degradation makes good structural stability.(2)For chitosan sponge,by adding 3%glycerol,we can get a flexible sponge with uniform pore distribution(diameter around 200 ?m).The porosity of the sponge is 94.9%.It has excellent elastic deformation.It also has excellent water vapor permeability and fast imbibition ability.Low degradation rate is a guarantee of stability.(3)For hydrogel/Luffa sponge compound,SEM shows good combination of hydrogel with loofah sponge.Hydrogel can both cover the fiber bundle and fulfill the hole of loofah sponge.Compound has good swelling properties with swelling rate of 280%and proper degradation rate.The hydrogel completely degraded after 7-days' culture.(4)The drug release and inhibition zone test stated that the release rate of drug from all three dressings is fast and all three dressings have certain antibacterial properties.Cytotoxicity test revealed the good biocompatibility of chitosan membrane.