The Preparation And Characterization Of Light-crosslinkable Antibacterial Hydrogels For Tissue Engineering

The repair of damaged human tissues and organs has entered a new stage with the promotion of tissue engineering and 3D printing technology.Now,progress has been made in the construction of bone,cartilage,skin and other tissues and organs,and the tissue repair has gradually entered the stage of clinical transformation.However,in the process of transplantation and postoperative recovery,engineered tissues are often exposed to the risk of microbial infection,which may lead to a second operation,amputation or even death in severe cases.Therefore,in this paper,EPL/modified gelatin(GelMA)hydrogel(EPL/GelMA)and modified EPL(EPLGMA)bioink were prepared based on natural antibacterial peptide ε-polylysine(EPL),and the possibility of their application in tissue engineering antibacterial field was explored.The main research contents and results are as follows:(1)Injectable photocurable antibacterial EPL/GelMA hydrogels with different EPL contents used in tissue engineering were prepared by combining EPL and GelMA.GelMA hydrogels containing EPL concentrations of 0,1,5,10,15 and 20 mg/m L,respectively named EPL0/GelMA,EPL1/GelMA,EPL5/GelMA,EPL10/GelMA,EPL15/GelMA and EPL20/GelMA hydrogels.EPL5/GelMA,EPL10/GelMA,EPL15/GelMA and EPL20/GelMA hydrogels showed antibacterial activity against Escherichia coli and Staphylococcus aureus,and the size of antibacterial ring was positively correlated with the concentration of EPL.Among the hydrogels,EPL5/GelMA hydrogel has good cell proliferation and cell adhesion,and has good cytocompatibility,which can be used in tissue engineering antibacterial field.(2)EPLGMA-1,EPLGMA-2 and EPLGMA-3 bioinks were obtained by grafting with glycidyl methacrylate(GMA)on EPL.The degree of carbon-carbon double bond grafting was 1.63 mmol/g,2.21 mmol/g and 3.01 mmol/g,respectively.The hydrogels EPLGMA-1H,EPLGMA-2H and EPLGMA-3H were obtained successively.The three hydrogels have good biocompatibility and have excellent antibacterial effect against Escherichia coli and Staphylococcus aureus.The inhibitory rates of EPLGMA-1H,EPLGMA-2H and EPLGMA-3H against Escherichia coli were 97.12±0.32%,95.53±0.34% and 95.51±0.35%,respectively.The inhibitory rates against Staphylococcus aureus were 99.97±0.04%,95.66±0.36% and 90.87±0.84%,respectively.The EPLGMA-3 bioink with the best in vitro construction ability of cartilage tissue was selected for 3D bioprinting and the printed hydrogels showed high fidelity of printing structure,uniform cell distribution and high survival rate,and excellent ectopic chondrogenesis performance.In conclusion,EPL/GelMA,the antibacterial hydrogel,and EPLGMA,the antibacterial bioink,prepared in this paper have good biocompatibility and excellent antibacterial performance,and are expected to play an important role in clinical transformation of tissue engineering.