The influence of surface energy on early adherent events of osteoblast on titanium substrates.

Surface energy of implant material is one of the important factors in the process of osseointegration. How surface energy regulates the signaling pathway of osteoblasts, however, is not well understood. Cell adhesion is one of the first steps essential to subsequent proliferation and differentiation of bone cells before tissue formation. Our present study was designed to investigate how surface energy may influence the early adhesion of human alveolar osteoblasts (AOBs). Substrates applied were two groups of titanium disks: (1) hydrophobic sandblasted and acid-etched (SLA) surfaces; (2) chemically modified hydrophilic SLA (modSLA) ones. Cell morphology and cell attachment were examined by scanning electron microscopy (SEM). Defined cytoskeletal actin organization was immunohistochemically examined using confocal laser scanning microscopy. RT-PCR was applied to detect and to compare the expression of focal adhesion kinase (FAK) of osteoblasts cultured on the two groups of substrates. The attachment rates of AOBs cultured on modSLA substrates were significantly higher than the cells on SLA ones within 3 h. AOBs on modSLA developed more defined actin stress fibers after 6 h of attachment. FAK expression was comparably higher on modSLA after 6 h. Within the limitation of the current study, higher surface energy of titanium surfaces enhanced the cell adhesion in the early stage of cell response and may work through influencing the expression of adhesion-associated molecules.