Research On Preparation And Application Of Antibacterial And Anti-drug Resistant Carbon Quantum Dot Double Network Hydrogel

Bacterial infections at wounds are a serious threat to human health and have become a major clinical challenge.The misuse of antibiotics has led to the development of bacterial resistance,and it is important to develop novel antibacterial substances for bacterial infections.Carbon quantum dots（CQD）are carbon particles with a particle size of less than 10 nm and have excellent biocompatibility.Studies have shown that carbon quantum dots prepared from some drugs still exhibit excellent antibacterial activity and can effectively avoid the production of drug-resistant bacteria,which has potential applications in improving the efficiency of treatment of bacterial infectious diseases.In this project,a double network hydrogel based on carbon quantum dot doping with wound healing promotion function was constructed by chemical-physical double cross-linking method for the treatment of infected wounds.In this study,carbon quantum dots(CQD_KN)of kanamycin sulfate were prepared by hydrothermal method using kanamycin sulfate as raw material,the CQD_KN double network hydrogel was prepared by forming the first layer of the hydrogel from CQD_KN,recombinant collagen（HLC）and oxidized dextran（ODex）by Schiff base reaction,and the second layer of the hydrogel from polyvinyl alcohol（PVA）by repeated freeze-thaw method,and the physicochemical properties,antibacterial properties,cytocompatibility and pro-wound repair properties of this CQD_KN hydrogel were characterized and evaluated.The physicochemical properties,in vitro biocompatibility,antibacterial properties and wound healing promotion properties of CQD_KN hydrogels were characterized and evaluated.The specific experimental results are as follows:（1）Preparation and characterization of CQD_KN:CQD_KN was characterized by transmission electron microscopy,X-ray powder diffractometer,Malvern particle size meter,UV spectrophotometer and fluorescence spectrophotometer.The results showed that CQD_KN with fluorescent properties was successfully prepared by hydrothermal method.（2）CQD_KN hydrogels with different carbon quantum dot contents were prepared to investigate the effects of carbon quantum dot contents on the pore structure,swelling rate and water retention properties of hydrogels.The results showed that the higher the content of CQD_KN,the smaller the pores of CQD_KN hydrogel,the smaller the swelling rate,and the better the water retention performance.（3）In vitro biological performance evaluation of CQD_KN double network hydrogel:The cytocompatibility of the hydrogel was investigated by blood compatibility assay,live-dead cell staining assay,cell scratching assay and cytotoxicity assay;the results showed that CQDKN double network hydrogel has good blood compatibility,no cytotoxicity and can promote cell proliferation and migration.（4）Evaluation of antibacterial performance of CQD_KN dual network hydrogel:The antibacterial resistance of kanamycin sulfate and CQD_KN to bacteria was investigated by the minimum inhibitory concentration（MIC）test,and the antibacterial performance of CQD_KN hydrogel was investigated by bacterial co-culture experiments.The results showed that compared with kanamycin sulfate,CQD_KN was less resistant to bacteria and CQD_KN hydrogel had certain inhibition effect on both E.coli and S.aureus.（5）Evaluation of CQD_KN double network hydrogel for promoting infected wound healing performance:A rat infected wound model was established,and the pro-wound healing performance of CQD_KN double network hydrogel was evaluated by Gram staining assay,hematoxylin-eosin staining assay,Masson staining,immunohistochemical assay and immunofluorescence assay.The results showed that CQD_KN double network hydrogel reduces wound inflammation,promotes collagen deposition and accelerates infected wound healing.In summary,the CQD_KN dual network hydrogel not only has antibacterial and drug resistance properties,but also has good biocompatibility to promote infected wound healing,and has broad application prospects in the field of wound dressings.