Integrin-mediated osteoblastic adhesion on a porous manganese-incorporated TiO2 coating prepared by plasma electrolytic oxidation

This study was conducted to evaluate the bioactivity of manganese-incorporated TiO2 (Mn-TiO2) coating prepared on titanium (Ti) plate by plasma electrolytic oxidation (PEO) technique in Ca-, P- and Mn-containing electrolytes. The surface topography, phase and element compositions of the coatings were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS), respectively. The adhesion of osteoblast-like MG63 cells onto Ti, TiO2 and Mn-TiO2 surfaces was evaluated, and the signal transduction pathway involved was confirmed by the sequential expression of the genes for integrins β1, β3, α1 and α3, focal adhesion kinase (FAK), and the extracellular regulated kinases (ERKs), including ERK1 and ERK2. The results obtained indicated that Mn was successfully incorporated into the porous nanostructured TiO2 coating, and did not alter the surface topography or the phase composition of the coating. The adhesion of the MG63 cells onto the Mn-incorporated TiO2 coating was significantly enhanced compared with that on the Mn-free TiO2 coating and the pure Ti plates. In addition, the enhanced cell adhesion on the Mn-TiO2 coatings may have been mediated by the binding of the integrin subunits, β1 and α1, and the subsequent signal transduction pathway, involving FAK and ERK2. The study indicated that the novel Mn-TiO2 coating has potential for orthopedic implant applications, and that further investigations are required.