Surface modification of bioceramics affect osteoblastic cells response

Poor cell adhesion to orthopaedic and dental implants may result in implant failure. Cellular adhesion to biomaterial surfaces is primarily mediated by integrins, which act as signal transduction and adhesion proteins. Since integrin function depends on divalent cations, we investigated the effect of magnesium ions modified bioceramic substrata (Al₂O₃-Mg²⁺) on human bone-derived cell (HBDC) adhesion, integrin expression and activation of intracellular signalling molecules. Our findings demonstrated that adhesion, spreading and expression of extracellular matrix proteins was increased when HBDC were cultured on Al₂O₃-Mg²⁺ compared to the Mg²⁺-free Al₂O₃. Moreover, these cells grown on Al₂O₃-Mg²⁺ expressed significantly enhanced levels of β1-, α5β1- and α3β1-integrins receptors. Tyrosine phosphorylation of intracellular integrin-dependent signalling proteins and She isoforms (p46, p52, p66) were significantly enhanced when HBDC were grown on Al₂O₃-Mg²⁺ compared to Al₂O₃. We demonstrated that Mg²⁺-promoted cell adhesion depends on α5β1- and β1-integrins associated signal transduction pathways involving the key signalling protein. Since Mg²⁺-modified substrata enhanced osteoblastic proliferation and differentiation, their potency to enhance osteogenesis is hereby suggested. Mg²⁺ supplementation of bioceramic substrata may be a promising way to improve integration of implants in orthopaedic and dental surgery.