Preparation And Performance Research Of Double Cross-linked Antibacterial Hydrogel For The Repair Of Infected Burn Wounds

The need for treatment of burn wounds is increasing due to the predominance of tissue damage and infected wounds due to burns,which kill many people every year.Hydrogel is a highly hydrophilic substance with a three-dimensional network that can significantly improve wound healing rates when used as a wound dressing and has been widely used in the biomedical field.However,hydrogel dressings applied to burn infected wounds usually do not have long-term antibacterial effects,and the small cross-linkage of some dressings and the excessive addition of antimicrobial agents can cause excessive toxicity and sudden release on the wounds,increasing the burden on the wounds,which is not conducive to wound repair.Therefore,the development of a drug delivery gel that allows a sustained or slower time-dependent controlled release is of interest for the treatment of burn wounds.In this paper,recombinant collagen grafted with 3-aminophenylboric acid hydrochloride and sodium alginate was used as the main raw materials.The metal organic framework material loaded with polyhexamethylene biguanide(PHMB)was added to the system.A double-crosslinked bacteriostatic hydrogel with a stable spatial structure was formed by interleaving the phenyl borate ester bond and the amide bond.The selected HLC has good biocompatibility and degradability,and the selected SA has good hemostatic properties and biocompatibility.The main findings are as follows:(1)ZIF-8 loaded with PHMB was synthesized as P-ZIF nanoparticles.The nanoparticles were synthesized by the solvothermal method.The loading rate of PHMB nanoparticles was changed by adding different amounts of PHMB into the reaction system.The nanoparticles were characterized by scanning electron microscopy and XRD.(2)Preparation and characterization of hydrogels: Firstly,recombinant collagen(HLC),one of the raw materials,was modified.The carboxyl group on HLC was activated by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide.Then3-Aminophenylboronic acid hydrochloride(APBA)was grafted onto HLC with an amide bond to form the HLC-APBA compound.Then,a double-crosslinked bacteriostatic hydrogel(HA/S/0.05% P-ZIF)with a stable spatial structure was formed through an amide bond and a phenyl borate ester bond.The swelling property,water retention property,ion release pattern,and degradation rate of hydrogel were also investigated.The results show that H-A/SA/0.05%P-ZIF hydrogel has better performance.(3)Biological evaluation of hydrogels: Bacterial inhibition performance of hydrogels against Escherichia coli and Staphylococcus aureus was evaluated by a bacterial agar plate assay.The biocompatibility of the hydrogel was investigated by a cytotoxicity assay and a live/dead cell staining assay.The ability of hydrogels to promote cell migration was investigated by cell scratching experiments.In this study,we established a deep Ⅱ degree scald infection model in rats to evaluate the potential of hydrogel as a biomedical material.In addition,histological evaluation of regenerated tissues at different healing stages was performed to reveal the healing process of these groups.The results show that hydrogel can reduce the rate of wound infection by inhibiting the growth of bacteria,reduce the level of inflammation,and accelerate wound repair by promoting collagen deposition and neovascularization.In summary,the hydrogel prepared in this study has good biocompatibility,degradability,can effectively inhibit the growth of bacteria and reduce the level of wound inflammation,and can accelerate the wound repair process by promoting collagen deposition and promoting neovascularization.Therefore,it has great potential for application in the field of biomedical materials.