Preparation Of ?-cyclodextrin Composite Hydrogel And Its Performance In Promoting Wound Repair

With the aging of the population and the increase of traffic accidents,there are more and more cases of skin wound injury,the wounds provide convenient conditions for bacterial invasion which will lead to wound infection and even life-threatening.?-Cyclodextrin(?-CD)hydrogels are widely used in biomedical fields such as wound repair and cancer treatment due to their good biocompatibility,stability,and modifiability.However,the lack of antibacterial properties and poor mechanical properties limit its further clinical application.Therefore,it is highly desirable to construct a?-CD composite hydrogel with good physicochemical properties and biological properties,which has important scientific research significance and clinical application prospects.Polyethyleneimine(PEI),as a typical cationic compound,is considered to be an effective antibacterial material,which can effectively improve the antibacterial properties of?-CD.In recent years,polyvinyl alcohol(PVA)hydrogels with excellent adhesion and biocompatibility have been widely used in the field of wound dressings.In this work,?-CD/PEI/PVA(BPP)composite hydrogel was designed and constructed by physical and chemical modification.It mainly explores the effects of different components on the physicochemical properties and biological properties of the composite hydrogel.The role of hydrogel components on wound repair is explored through a rat skin total injury infectivity model,and it is clarified the mechanism of BPP hydrogel to promote wound healing.The main results of this study are:1.We explored the influence of different components of hydrogel on the physical and chemical properties and biological properties of the material,and prepared?-CD/PEI(BP),PVA and BPP hydrogels respectively.The results show that the physical cross-linking network of PVA in BPP improves the reversible deformability of the material,and the chemically cross-linked network of BP greatly improves the modulus and strength of the material.Through the construction of a dual network(including BP chemical network and PVA physical cross-linking network),the BPP hydrogel has excellent deformability and self-healing properties,which is beneficial to the protection of wounds.In addition,the damaged BPP hydrogel can be healed into a whole,and the healed BPP hydrogel can withstand a certain amount of stretching,and the elongation at break can reach 150%.Bacterial experiments show that BP and BPP hydrogels have excellent antibacterial properties against both Gram-positive S.aureus and Gram-negative E.coli.For the bacterial solution with a concentration of 10⁷ CFU/m L,the antibacterial rate of BPP can reach100%.The main source of its antibacterial properties is the cationic polymer PEI,PEI is chemically modified into tertiary aminated polyethyleneimine TPEI,TPEI can effectively act on the membrane structure of bacteria through contact sterilization,lead to bacterial breakdown and death.In addition,BPP hydrogel has good biocompatibility with mouse fibroblasts L929,mouse embryonic fibroblasts NIH3T3,and human umbilical vein endothelial cells HUVECs,and also maintains good blood compatibility.2.The antibacterial properties of the hydrogel in vivo and its wound healing ability were studied by constructing an infectious model of SD rat skin with total damage.The in vivo antibacterial properties of the hydrogels were evaluated by bacterial coating experiments on the wound surfaces.The in vivo antibacterial rate of BPP hydrogels against Staphylococcus aureus at 10⁷ CFU/m L was 100%.We observed and photographed the morphological state of the wound through different days and used Image J software to simulate the healing process to evaluate the effect of hydrogel on wound healing.The results show that the BPP hydrogel has an obvious effect of promoting healing:the healing rate of BPP group can reach 76.24±2.34%on the 7^th day after operation,which is significantly better than the control group(Medical sterile patch group)(58.30±2.33%).Besides,the healing rate of BPP hydrogel on the 14^th day almost reached 100%.Finally,the inflammation,collagen deposition and micro-angiogenesis of wound tissue were evaluated by immunohistochemical staining(such as H&E,Masson and VEGF staining).The results show that the BPP hydrogel can effectively slow down the inflammation caused by bacterial infection and promote the orderly deposition of collagen and the expression of VEGF to accelerate the process of wound healing.