Preparation And Properties Of Biomimetic Mussel Polyglutamic Acid Based Photocurable Adhesive Hydrogels

Rapid and effective wound closure is an important clinical problem.Traditional suture treatment is time-consuming,causes secondary trauma to the wound and requires subsequent removal.In order to improve the efficiency of wound treatment,tissue adhesive has been developed as an alternative treatment method.Among current commercial tissue adhesives,biological adhesives are difficult to balance the mechanical properties of the material and the bonding effect,while chemical adhesives are often difficult to degrade.Mussel proteins have excellent biocompatibility and tissue adhesion ability,and the catechol group is the main source of their adhesion properties.As a gel system based on non-covalent bond self-assembly,the host-guest hydrogel has many advantages such as simple preparation,reversible self-assembly and degradability,which can effectively regulate the mechanical strength and degradation rate of the material when combined with the photocrosslinking system.Based on the good water absorption and biocompatibility of polyglutamic acid,this thesis prepares tissue adhesion hydrogels with adjustable degradability by introducing cyclodextrin-cholic acid molecule pairs as side groups to construct host-guest gels and introducing catechol groups containing double bonds to participate in photocrosslinking,which is divided into two main parts.(1)By activating carboxyl groups on polyglutamic acid side groups and grafting bile acid and cyclodextrin molecules respectively as precursors,a host-guest cross-linked self-healing hydrogel system with certain mechanical strength was constructed.A reasonable balance of mechanical strength and adhesion capacity was achieved by introducing double bonds to the polyglutamic acid side groups and participating in light curing with dopamine methacrylamide containing double bonds.The experimental results show that polyglutamic acid hydrogels have stable mechanical properties and self-healing properties,and have excellent adhesion properties to a variety of matrix materials including skin and liver with a adhesive stress of 5 k Pa.Moreover,polyglutamic acid hydrogels exhibited low cytotoxicity to3T3.In addition,in vivo evaluation further confirmed that polyglutamic acid hydrogels have good wound closure,thus promoting healing of body surface wounds,and good biocompatibility.(2)In view of the clinical demand for antimicrobial wound dressings and the many different demands on the degradation rate of wound closure materials,polyvinyl alcohol side groups were quaternized with the introduction of double bonds,and the antimicrobial composite hydrogels were prepared using light-cured cross-linking and polyglutamic acid with side groups containing double bonds.The experimental results showed that the addition of polyvinyl alcohol could significantly reduce the degradation rate of the gel system and significantly improve the stability.In vitro antibacterial experiments showed that the hydrogel precursors had good bactericidal properties against both Gram-positive and negative bacteria,where the killing rate of bacteria was more than 96% when material concentration reaches10μ g / m L.The activity experiments on 3T3 cells also demonstrated that the composite antibacterial hydrogels have good biocompatibility and have great potential for application in the biomedical field,especially as antibacterial wound closure dressings.