Study On Novel Lysine Based Nanogel Grafting Silk Sutures Against Pathogents

On the basis of the characteristics of easy operation and stabilization, natural silk protein fiber woven medical silk sutures have become one of the widely used sutures in society. But as general unabsorbed sutures, silk sutures have no inhibitory effect on bacterias, viruses and other similar organisms. Weave structure gaps between single fibers inside the thread could provide hiding places for organisms which increased the probability of surgical site infection(SSIs). In consideration of antibacterial and biocompatibility features, devolping sutures containing antimicrobial substances to prevent bacterial adsorption and block bacteria contact with incision are necessary to reduce the probability of SSIs. Therefore, the research about antibacterial properties of medicinal silk suture has important clinical value.In this work, a novel biodegradable L-lysine based nanogels was applied as the antibacterial agent carrier. Triclosan was chosen as the antibacterial agent after investigate of the usage of colleges and universities. The nanogel was grafted on the surface of the silk suture according to the chemical graft copolymerization. The results had shown that the grafting silk sutures have a long-term efficacy against pathogens such as S. aureus and E. coli. Particularly, and these grafting sutures have a stable size of inhibition zones on agar plates in the first four days of antibacterial efficacy assay. The antimicrobial results could be sufficient evidence in the wound area to prevent potential early wound infection. In the meanwhile, mechanical strength tests indicated negligible distinction between grafting silk sutures and commercial sutures. This technique demostrates a novel biocompatible and biodegradable lysine based nanogel grafting silk sutures, and provides a new, effective, and universal approach for the treatment of bacterial infections.The drug loaded hydrogel were synthesized by pre-loading a chemical synthesis method. The triclosan loaded nanogels(NGTL) were synthesized by a convenient enzymatic degradation of macrogels, namely, trypsin triggered triclosan loaded macrogel degradation into NGTL. Through to the drug antibacterial function evaluation of hydrogel nanoparticles, confirmed none antibacterial function of the nanogels and the antibacterial effectiveness of triclosan. Future more, we studied the antibacterial durability of the chemical grafting silk sutures and a comparative antimicrobial persistence research with clinical antibacterial suture products abroad. Two kind hydrogels were selected to study the antibacterial function influence to sutures of the crosslinking density(hydrogels 4-Lys-4(1.5:1) and 4-Lys-4(2:1)). These triclosan loading nanogels were grafted to the silk sutures to complete the antibacterial treatment of sutures. Drug slow release analysis was applied to the two kind triclosan loaded nanogels. SEM analysis and antibacterial slow-release performance test were applied to the graft sutures. Relevant evaluations of physical and mechanical properties were used to analysis the difference after chemical treatment.The main conclusions are as follows: After 7 days biodegradation in the enzyme solution, the diameter of hydrogels 4-Lys-4(1.5:1) and 4-Lys-4(2:1) were measured about 60 nm and 90 nm. Two kind nanogels both had narrow diameter distribution make for the stability of slow release rate of triclosan. Higher crosslinking density nanogels 4-Lys-4(2:1) were obtained with higher drug-loading rate; Drug-loading nanogels for staphylococcus aureus and escherichia coli have excellent antibacterial function, nanogels have no antibacterial function about e. coli and s. aureus; After the chemical treatment, mechanical properties, diameters and weave structure of the chemical grafting silk sutures basically have no changed, conform to the government standard; The two grafted antimicrobial silk sutures have long-term efficacy against pathogens such as S. aureus and E. coli. Compared to abroad clinical used antibacterial suture Vicryl Plus, grafted sutures have longer antibacterial aging. And the higher cross linking density antibacterial nanogels grafted silk sutures, have the better sustained release antibacterial function.