Systematic variation in osteoblast adhesion and phenotype with substratum surface characteristics

Time-varying interactions of human fetal osteoblastic cells (hFOB 1.19) with materials of diverse chemical composition and surface energy, including biodegradable lactide/glycolide-based polymers, were assessed using a combination of assays sensitive to different phases of cell-substratum compatibility. Short-term (minutes to hours) cell-attachment-rate assays were used to measure the earliest stages of cell-surface interactions leading to adhesion. Proliferation-rate assays quantifying viability of attached cells were applied as a measure of medium-term (hours to days) cytocompatibility. Both attachment- and proliferation-rate assays were found to strongly correlate with material surface energy, with the exception of a reproducible and significant adhesion preference for fully water-wettable quartz over glass. No such adhesion/proliferation preference was observed for hydrophobized counterparts, and attachment to water-wettable glass was significantly less than that to control tissue culture polystyrene. These results suggest that the amorphous SiO(x) surface was inhibitory to hFOB 1.19 growth whereas putatively crystalline quartz stimulated bioadhesion. Alkaline phosphatase activity was evaluated as a marker for long-term (days) differentiation of hFOB 1.19 cells and did not strongly correlate with surface energy or, in the case of biodegradable polymers, chemical composition.