Study On The Self-assembly Of Snail Pedal Mucus And Silk Fibroin/snail Mucus Protein Composite Adhesive

The research on artificial imitation of natural protein is one of hot spots in the field of materials.In recent years,some progress has been made in the study of gene synthesis protein,biomimetic processing technology,and the relationship between structure and performance of protein.Snail mucus(SM)has been applied in biomedical research for a long time in foreign countries due to its unique viscoelastic properties and treatment effects on respiratory and skin diseases.Silk fibroin(SF)as a natural protein has also been applied widely in biomedical field due to its impressive biocompatibility,biodegradability,and mechanical properties.Therefore,through the study on the relationship between structure and properties of SM,we can imitate its unique composition and structural features.The combination of SM and SF to obtain the medical adhesives with high performance and added value will be the opening and innovation in the field of biomaterials.In this paper,we firstly presented an intriguing example that the white jade snail could ingeniously employ various structures of secreted SM from the nanoparticles to the viscous silks for crawling on different angles of smooth planes.This structural transformation process was mainly attributed to the unique combination of amino acid composition and chemistry in secreted glycoprotein coupled with the calcium regulation in pedal gland.The viscosity of corresponding SM was increasing which facilitated the snail crawling higher angle plates.On the basis of the composition and structure of SM,we systematically studied the effects of allantoin and glucuronic acid on the morphology,structure and properties of silk fibroin solution.Furthermore,we revealed the mechanism of these two compounds in regulating the structure of silk fibroin and promoting the gelation transformation.Then snail mucus protein(SMP)as a glycoprotein was allowed to blend with SF solution forming a composite adhesive.We found that SMP could promote the formation of more stable ?-sheet of SF molecules in the water.Then the gelation of SF solution was accelerated resulting in the rapid increase of macro-viscosity.SF /SMP composite adhesive had better adhesion strength and shorter effective curing time compared with single component.Its adhesive strength could reach near 20 k Pa after 72 hours in the pig skin bonding model.The parameters as different SF/SMP ratio,concentration,smear volume,adhesion time,temperature and humidity have obvious influence on the adhesive strength.Finally,in vitro cell culture test results showed SF/SMP composite adhesive had good biocompatibility which could support the adhesion,differentiation and proliferation of human skin fibroblasts(HS865)and mouse embryonic fibroblasts(NIH3T3).In summary,SF/SMP composite adhesive has the potential to be applied as a soft tissue adhesive in bonding and repairing of skin wounds.In this paper,we clarified the preparation and gluing mechanism of SF/SMP composite adhesive,which showed high adhesion strength to skin tissue and good biocompatibility.In summary,SF/SMP composite adhesive has the potential to be applied as a soft tissue adhesive in bonding and repairing of skin wounds.