| Summary: | The effects of alkaline pH on the initial adhesion of osteoblasts to titanium surfaces was analyzed by single cell force microscopy (SCFM). In the SCFM measurements, the same cells were used to compare their unspecific adhesion to uncoated titanium with their specific adhesion to collagen coated titanium. When the maximum detachment forces (MDFs) were compared at pH 7.4 and 8.0, only slight differences were found on pure titanium, while the MDFs were significantly increased at collagen coated surfaces at pH 8.0. Effects on the subsequent proliferation and gene expression were investigated in an in vitro model system consisting of an alkalizing polyvinyl alcohol (PVA) matrix and a perforated titanium disc. The sodium hydroxide releasing matrix maintained the medium pH between pH 7.6 and pH 8.4 during the entire experiment. Under these conditions, cell counts were significantly increased with respect to the control system after 7 days in culture. These results were supported by gene expression analyses, which showed an upregulation of proliferation-controlling genes of the EGFR1 and PI3K/AKT pathways after 14 days in culture. The SCFM data were complemented by findings of an intensive regulation of genes known to be associated with focal adhesion such as Itga8 and Tnn.
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