Study On Preparation And Performance Of Chitosan-based Fuctional Composite For Post-operative Anti-adhesion Wound Dressing

Adhesion is one of the most common post-operative complications,which occurs during the healing process of damaged tissues.Sometimes it induces to some symptoms like inflammation,pain and even movement disorders.Therefore,tissue adhesion may severely affect daily life of patients.Nowadays,the most effective clinical tool to prevent post-operative tissue adhesion is the use of polymer antiadhesion materials to physically separate the affected tissue,which is becoming a hot research topic.These materials can not only meet the requirements of easily handle in clinical application,biocompatibility,biodegradability,but also can provide a reliable barrier to prevent the target site from tissue adhesion.In recent years,few polymer barrier materials have been able to fully meet these requirements.Therefore,in this paper,we applied N,O-carboxymethyl chitosan as a matrix material for various post-operative anti-adhesion materials and studied its properties.N,O-CS/ORC composite gauze is compound of N,O-CS and ORC,which surface has good water solubility,a great cell compatibility,hemocompatibility,and degradability in vivo.Post-operative trauma,bleeding,inflammation and pathogen infection in the course of surgery,etc are the main causes of post-operative adhesion.Therefore,the excellent hemostatic effect and antibacterial properties of N,O-CS/ORC composite gauze are helpful to implant the composite gauze into the rat cecum abrasion-sidewall defect model,preventing post-operative adhesion within 14 days.TEMPO was used to oxidize cellulose nanocrystals and obtain TOCN,compounded with N,O-CS to obtain N,O-CS/TOCN composite sponge.As a natural antibacterial polymer,EPL exhibits innate antibacterial properties without the assistance of other exogenous antibiotics.The prepared EPL/N,O-CS/TOCN composite sponge performs excellent antibacterial properties,and the bacteriostasis rate of sponge reaches 90%.SEM images showed that the sponge had a regular massive pore structure,and TOCN was evenly distributed in N,O-CS.Besides,the cytotoxicity tests showed that the materials have a good cell compatibility.The results of blood cell and platelet adhesion experiments illustrated that EPL/N,O-CS/TOCN could achieve fast clotting.Due to its high porosity,the material can absorb a large amount of blood to accelerate the coagulation and activate platelets through the carboxyl group to further blood clotting.The composite sponge has a good degradation effect and can be completely degraded after 21 days of implantation.After 14 days of implantation,the composite sponge could be degrading completely and the inflammatory response disappears,at the same time the wound is completely repaired.NaIO4 was used to epoxide dextran in order to obtain ODA.The amino group in N,O-CS and aldehyde group in ODA were cross-linked by Schiff's base to form a flexible hydrogel.This hydrogel represents an excellent skin adhesion,which makes it suitable for sealing bleeding wound surface as well as obtain rapid hemostasis.In addition,N,O-CS/ODA hydrogel formed in situ,which perfectly integrates with the wound tissue to accelerate wound healing and tissue regeneration.In vitro cell experiments showed that N,O-CS/Ohydrogel showed a good cytocompatibility and could effectively inhibit the fibroblasts adhesion.It can be completely degraded after 21 days of implantation with great antibacterial performance and biocompatibility,which prevents wound infection and inflammation.Then we implanted the hydrogel into rats with an abdominal wall-cecum defect.After 14 days,the wound was entirely repaired,effectively reducing the probability of abdominal tissue adhesion on wound repair without side effects.The anti-adheison effects of N,O-CS/ORC composite gauze,EPL/N,O-CS/TOCN antibacterial composite sponge and N,O-CS/Ohydrogel were studied by the model of abdominal wall injury-cecum defect in SD rats.N,O-CS/ORC composite gauze,EPL/N,O-CS/TOCN antibacterial composite sponge and N,O-CS/ODA hydrogels have the inherent hemostatic effect of chitosan,and there were unreacted carboxyl groups.It firstly activated platelets to adhere the red blood cells and then accelerated the formation of thrombus.After that,the unreacted carboxyl groups would combine with Fe3+to improve the hemostatic effect of wound,preventing postoperative adhesion.The massive pore structure of the EPL/N,O-CS/TOCN composite sponge accelerates the rate of hemostatic.The antibacterial effect of N,O-CS/TOCN composite sponge was enhanced by the introduction of EPL,with the bacteriostatic rate reached 90%,thus effectively preventing the post-operative adhesion effect.N,OCS/ODA hydrogel has injectable,self-healing,antibacterial,skin applicability and adhesion properties,which enables the hydrogel to achieve rapid hemostasis,healing and tissue regeneration,making post-operative anti-adhesion rate reached above 90%.