Study On Properties And Preparation Of Gas-filled Prostheses Made By Silicone Rubber With Silver-loaded Nano-TiO₂

Objective: To evaluate the antibacterial activity and biocompatibility of silicone rubber with silver-loaded nano-TiO₂ (SRSNT) in vitro. To evaluate the feasibility of SRSNT applied to repair early maxillary defects after maxillectomy, and found the method of repairing.Material and Method: The antibacterial activity property of silver-loaded nano-TiO₂ was examined by the antibacterial circle test. The antibacterial agent of silver- loaded nano-TiO₂ was added to medical silicone rubber materials by the weight rate of 0 0.5,1,1.5,2,2.5 agent/material respectively, then the mixtures were formed into 1.5mm thick sheet and vulcanized under 140℃for 1.5h. The antibacterial effect of the silicone rubber was examined by in vitro bacteria culture. MTT assay method was used to evaluate the cytotoxicity of SRSNT to the rat fibroblast cells L929.Cell culture method was used to assesse the influence of SRSNT on adhesion of L929. Hydrophilicity was evaluated by measuring the contact angle formed between water drops and the surface of the samples using Optical Contact Angle Measuring Device. The silastic prosthesis was fabricated by modification silicone rubber.Result: According to《Technical Standard For disinfection》, silver-loaded nano-TiO₂ has outstanding antibacterial property. With the increasing of silver- loaded nano-TiO₂ content, the inhibition rates of the samples increased. The inhibition rate of 2wt% and 2.5wt% samples was 100%. The MTT test showed the leaching liquor with 100%. 50%, 10% concentrations of modification silicone rubber was nontoxic to L929. SEM showed that L929 cells adhered to 2wt% sample surfaces were more than that of 0wt% samples. L929 cells were flat and extended to long spindle shapes on the surface of 2wt% samples, while most L929 cells of the surface of 0wt% samples rolled up. The contact angle between water drops and the surface of 0wt % SRSNT was 105.4°,while the contact angle between water drops and the surface of 2wt% SRSNT was 97.7°Conclusion: SRSNT has outstanding antibacterial property and is nontoxic to L929. Hydrophilicity and cell adhesion of silicone rubber can be improved by adding silver-loaded nano-TiO₂. Gas-filled silastic prostheses that are fabricated by SRSNT can be used for repairing early maxillary defects after maxillectomy.