Effect of surface chemical modification of bioceramic on phenotype of human bone-derived cells

In the search for methods to improve the biocompatibility of prosthetic mat erials, attention has recently been directed toward the potential use of su rface chemical modification and its influence on cellular behavior. This in vitro study investigates the effect of surface chemistry modification of b ioceramics on human bone-derived cells (HBDCs) grown on biomaterial surface s for 2 weeks. Cells were cultured on either alumina (Al2O3), alumina doped with magnesium ions ([Mg]-Al2O3), or hydroxyapatite (HAP), as well as tiss ue culture polystyrene (TCPS). Expression of alkaline phosphatase (ALP), th rombospondin (Tsp), osteopontin (OP), osteocalcin (OC), osteonectin (ON/SPA RC), type I collagen (Col I), and bone sialoprotein (BSP) were determined i n terms of mRNAs and proteins, Protein levels for ALP, OF, OC, and BSP were significantly (p < 0.05) greater at day 5 in HBDCs cultured on [Mg]-Al2O3 compared to those cells grown on Al2O3. At day 14 the levels of ALP, Tsp, C ol I, OF, ON/SPARC, and BSP rose significantly (p < 0.09) above those occur ring in HBDCs grown on Al2O3, HAP, and TCPS. This suggests that HBDCs from the same patient respond to differences in the surface chemical groups. Thi s study confirms that the chemistry of a substratum, which facilitates cell ular adhesion, will enhance cellular differentiation. (C) 1999 John Wiley & Sons, Inc.