In vitro evaluation of cytocompatibility of silicone used in plastic implants

There are many methods for screening implant materials including in vitro cell compatibility tests. In this study a few in vitro cytotoxicity systems have been applied to test the behaviour of clinically used silicone, in order to detect possible unrecognized toxic effects. The methods described include: 1) plating efficiency test, which employs established line fibroblasts to measure the residual capability of cells treated with biomaterials to adhere to the substrate and to spread; 2) MTT test, which verifies the integrity of mitochondria in peripheral blood lymphocytes exposed to silicone; 3) the lymphocytes transformation test, which measures the mitogen-driven proliferation of peripheral blood lymphocytes, always after exposure to silicone. The results obtained using these methods, which require a 24-72 h period of contact between silicone extract and cells, show that both silicone gel and silicone elastomer used in plastic implants do not cause acute cytotoxicity effects in cultured cells. Moreover, they do not seem to induce activation in cells.