Cytocompatibility of high strength non-oxide ceramics

Oxide ceramic materials like alumina (Al2O3) and zirconia (ZrO2) are frequently used for medical applications like implants and prostheses because of their excellent biocompatibility and high wear resistance. Unfortunately, oxide ceramics cannot be used for minimal invasive thin-walled implants like resurfacing hip prostheses because of their limited strength. The hypothesis Of this study is that non-oxide ceramics like silicon nitride (Si3N4) and silicon carbide (SiC)-not previously used in the medical field-are not only high strength and mechanically reliable ceramic materials due to their high amount of covalent bonds, but also exhibit a suitable biocompatibility for Use as medical implants and prostheses. Mechanical investigations and cell culture tests with mouse fibroblast cells (L929) and human mesenchymal stern cells (hMSC) were performed on the ceramics. An excellent cytocompatibility was demonstrated by live/dead stainings for both L929 cells and hMSC. HMSC were able to differentiate towards osteoblasts on all tested ceramics. The determined strength of silicon nitride and silicon cat-bide was shown as significantly higher than that of oxide ceramics. Our results indicate that the high strength non-oxide ceramics are material candidates in the future especially, for highly loaded, thin-walled implants like ceramic resurfacing hip prostheses. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res 93A: 67-76, 2010