The cytotoxicity evaluation of Kevlar and silicon carbide by MTT assay

The MTT test has been widely used as a rapid and sensitive method for screening anticancer drugs. In this paper, we used this method to assess the cytocompatibility of three materials: Keviar 29, silicon carbide and polyvinyl chloride (PVC) in both a quantitative and a qualitative manner. The materials were prepared by cleaning in 70% ethanol, autoclaved or gamma-sterilized. Extracts were prepared at four time periods (1, 2, 3 and 4 weeks) and two temperatures (37°C and 80°C). The extracts were used in the MTT assay and the data were collected and analysed with ONEWAY and DUNCAN procedures using the statistical computer package SPSS^x. The MTT staining procedure was also used in direct contact with the materials. The result from the MTT assay demonstrated that Kevlar, SiC and PVC extracted at 37°C were not cytotoxic while PVC extracted at 80°C did show some cytotoxicity, especially the material that had been gamma-sterilized. In the direct contact test the Kevlar showed no cytotoxicity. The SiC did show some localized toxicity when the material had been autoclaved, however, SiC subject to prior cleaning with ethanol showed no cytotoxicity. The PVC that had been autoclaved caused a cytotoxic response whereas the material that had been gamma-sterilized or cleaned in ethanol showed good cytocompatibility. This paper demonstrates that the MTT staining procedure is a useful technique to study the cytocompatibility of materials in both a quantitative and a qualitative manner. It is also shown that the cellular response to the materials tested is dependent on the method of preparation.