Role of wettability and nanoroughness on interactions between osteoblast and modified silicon surfaces

Development of new biomaterials is a constant in regenerative medicine. A biomaterial's surface properties, such as wettability, roughness, surface energy, surface charge, chemical functionalities and composition, are determinants of cell adhesion and subsequent tissue behavior. Thus, the main aim of this study was to analyze the correlation between changes in wettability without topographical variation and the response of osteoblast-like cells. For this purpose oxidized silicon surfaces were methylated to different degrees. Additionally, the influence of nanoroughness, and the subsequent effect of hysteresis on cell behavior, was also analyzed. In this case oxidized silicon pieces were etched with caustic solutions to produce different degrees of nanoroughness. Axisymmetric drop-shape analysis and atomic force microscopy confirmed that the proposed surface treatments increased the nanometer roughness and/or the water contact angles. MG-63 osteoblast-like cells were cultured on the altered surfaces to study proliferation, and for ultrastructural analysis and immunocytochemical characterization. Increasing the nanometer surface roughness or water contact angle enhanced osteoblast behavior in terms of cell morphology, proliferation and immunophenotype, the effect provoked by methylation being more significant than that caused by nanoroughness. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.