In vitro cytotoxicity of nitric oxide-releasing sol-gel derived materials.

Abstract

The cytotoxicity of bare and PU-coated nitric oxide (NO)-releasing sol-gel derived materials (sol-gels) was investigated using L929 mouse fibroblasts in both direct and indirect contact models to differentiate between the biological impact of the sol-gel matrix and NO release. The flux of NO was varied up to 150 pmol cm(-2) s(-1) using N-(6-aminohexyl)-aminopropyltrimethoxysilane (balance iso-butyltrimethoxysilane) diazeniumdiolate (NO donor)-modified sol-gels. The addition of a polyurethane (PU) outer membrane greatly improved the stability of the sol-gel matrix without significantly suppressing the NO flux. Direct contact studies demonstrated a cytotoxic effect that was dependent on the aminosilane content of the sol-gel. The use of the thin PU overcoat eliminated this effect. A direct cytotoxicity dependence of NO release for L929 fibroblasts was discovered from indirect contact studies, where 24 h exposure to NO fluxes in excess of 50 pmol cm(-2) s(-1) was cytotoxic.