Analysis Of The Influence Of Nano SiO₂ Silver Composite Antibacterial Agent On The Antibacterial And Mechanical Properties Of Silicone Rubber

Objective:Construction of antibacterial silicon rubber based on silica nanosilver composite modified antibacterial agents to study their physicochemical properties,antibacterial properties,biosafety and mechanical properties,so as to provide a strong technical support and theoretical basis for preparing biomedical silicon rubber with high efficiency,long-lasting and safe antibacterial effects.Methods:1.Preparation and characterization of silica nano silver antibacterial agent.Using silver nitrate（Ag NO₃）and nano-silica（SiO₂）,a silver loaded nano-silica composite antibacterial agent was obtained through a series of chemical reactions.Its related characterization was tested,its thermal decomposition characteristics were evaluated,and the antibacterial performance of the silver loaded nano-silica composite antibacterial agent was tested by bacteriostatic ring method and bacteriostatic plate counting method.2.Preparation and performance testing of antibacterial silicone rubber.Respectively weigh a certain amount of silver loaded nano SiO₂composite antibacterial agent and fully physically mix it with natural silicone rubber,and use a vulcanizing machine to conduct high-temperature vulcanization and pressing molding to prepare antibacterial silicone rubber sheets.The macroscopic morphology of silver loaded nano SiO₂composite antibacterial silicone rubber was observed,and its antibacterial properties were tested using bacteriostatic plate method.Its mechanical properties were evaluated by testing tensile strength,tear strength,elongation at break,and Shore hardness.Its biocompatibility was evaluated by CCK-8 test and hemolysis test.Results:1.Observation by scanning electron microscopy（SEM）and transmission electron microscopy（TEM）showed that the average particle size of silver nanoparticles was about 20nm,and the morphology of Ag NPs was relatively uniform and roughly spherical.Nm SiO₂loaded on the surface of Ag NPs formed SiO₂@Ag NPs The particle size of the composite antibacterial agent was around 25-35 nm.Fourier infrared（FT-IR）spectroscopy was used SiO₂@Ag NPs Characterization of the surface functional groups it is known that nano-SiO₂effectively combines with Ag NPs.The novel antibacterial agents overcome the disadvantage of easy oxidation of Ag NPs and have better antioxidant properties and stability.The antibacterial activity of the novel antibacterial agent against E.coli and S.aureus was superior to that of single Ag NPs due to the synergistic antibacterial effect.2.A new antibacterial silicone rubber sheet was prepared by combining a new antibacterial agent and silicon rubber（SR）by sulfurization blending method.The mechanical properties showed that the addition of the antibacterial agent component of nano-sio2-silver composite increased the tensile and tear strength of SR film by 30%,and the hardness did not change significantly,but the elongation at break decreased by 20%compared with before,as evident by SiO₂@Ag NPs The mechanical properties of the films were significantly higher than those of natural silicone rubber.Nm was tested by means of an antibacterial loop SiO₂@Ag NPs Antibacterial properties of antibacterial silicone rubber the results showed its good antibacterial effect,and calculated that,when the content of added antibacterial agent was 25mg/ml,the minimum inhibitory concentration was reached.Nm was tested by the CCK-8 assay SiO₂@Ag NPs Toxicity of antibacterial silicone rubber on normal cells,the RGR of antibacterial silicone rubber in each group was more than 75%,according to the evaluation criteria of RGR cytotoxicity grading:the RGR value was≥75%,and the cytotoxicity grade was 0 or 1,which was qualified.The number of cells in each group increased with time,and the normal cell morphology was maintained.It can be seen that all groups of antibacterial silicone rubber have good biosafety.Conclusion:In this study,SiO₂was selected to load on Ag NPs and then to construct a novel composite antibacterial agent,which overcame the problems of suboptimal antibacterial resistance,low sustained release and insufficient durable antibacterial ability caused by the easy oxidation and easy agglomeration of Ag NPs;Finally,the nanocomposite antibacterial agent was blended with natural liquid silicone rubber by physical blending method SiO₂@Ag NPs Antibacterial silicone rubber sheets.On the basis of overcoming Ag NPs agglomeration and oxidation,we can achieve its good compatibility and dispersibility in silicone rubber by surface modification of antibacterial agents,and optimize its antibacterial effect while improving the physicochemical properties of antibacterial silicone rubber,so that the antibacterial properties and mechanical properties of antibacterial silicone rubber can be at the optimal level without the interaction between each other,so that it can produce antibacterial persistent and inexpensive nano SiO₂@Ag NPs Antibacterial silicone rubber provides a strong theoretical basis.