Effects of roughness, fibronectin and vitronectin on attachment, spreading, and proliferation of human osteoblast-like cells (Saos-2) on titanium surfaces

The influence of surface roughness and the presence of adhesion molecules i n the culture medium were studied regarding cell adhesion, shape, and proli feration of osteoblast-like cells grown on two types of titanium disk. Type I disks were acid etched and type II disks were sandblasted and acid etche d. Surface roughness was determined by contact profilometry and scanning el ectron microscopy. Chemical composition and oxide thickness of the superfic ial titanium layer were established with energy dispersive Xray spectrometr y, electron spectroscopy for chemical analysis and auger electron spectrosc opy. Titanium release in the culture medium was assessed by inductively cou pled plasma-optical emission spectrometry. Osteoblast-like cells (Saos-2) w ere cultured on both types of titanium disks (1) in standard conditions (DM EM culture medium supplemented with fetal calf serum), (FCS), (2) with the culture medium alone (DMEM alone), (3) in the presence of fibronectin or vi tronectin (DMEM supplemented with fibronectin or vitronectin). Cultures wer e also performed in the presence of monoclonal anti-integrin (beta(1), alph a(v)) to test the cell adhesion molecules involved in the cell binding to t he titanium surface. We found that sandblasting does not modify the chemica l surface composition and that titanium represents only 5-6% (in the atom p ercentage) of surface elements. Release of titanium in the culture medium w as found to increase from 24 to 72 hours. In the absence of FCS, fibronecti n, or vitronectin, cells appeared scanty and packed in clusters. On the con trary, cells cultured in the presence of FCS, fibronectin, or vitronectin w ere flattened with large and thin cytoplasmic expansions. The addition of a nti beta(1) or alpha(v) integrin subunit monoclonal antibody in the culture medium decreased adhesion and spreading of cells, particularly in the pres ence of fibronectin. Cell proliferation was significantly higher on culture plastic than on both types of disks, but was increased on rough but not on smooth surfaces. These results indicate that a high surface roughness and presence of fibronectin or vitronectin are critical elements for adhesion, spreading, and proliferation of cells on titanium surfaces.