The effect of substrate topography on hFOB cell behavior and initial cell adhesion evaluated by a cytodetacher

Abstract

This study examined human fetal osteoblast (hFOB) cell morphology, adhesion force, and proliferation on a titanium-coated grooved surface. V-shaped grooves with a depth of 2.4 μm (T1) or 4.8 μm (T2) were produced in silicon wafers using photolithography and wet etching techniques. The grooved substrates were coated with a 200-nm-thick layer of titanium using a sputtering system. Smooth Ti-coated Si wafers were used as control surfaces. Analysis of the scanning electron microscopy observations shows that the cells responded to the micropattern by spreading out and becoming elongated. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay indicated that the grooved specimens had a significantly larger number of cells than did the control group after 5- and 15-day cultures. The cytocompatibility of specimens was quantitatively evaluated by a cytodetacher, which directly measures the detachment shear force of an individual cell to the substrate. After 30-min culture, the cell adhesion forces were 48.4, 136.6, and 103.3 nN for the smooth specimen, the T1 specimen, and the T2 specimen, respectively. The cell adhesion strengths were 294, 501, and 590 Pa for the smooth specimen, the T1 specimen, and the T2 specimen, respectively. The cell adhesion force and cell adhesion strength indicate the quality of cell adhesion, explaining the largest number of cells on grooved specimens. The experimental results suggest that the grooved patterns affect the cell shape and cytoskeletal structure, and thus influence the cell proliferation and cell adhesion force. The cytodetachment test with nanonewton resolution is a sensitive method for studying cell-biomaterial interaction.