The enhanced integrin-mediated cell attachment and osteogenic gene expression on atmospheric pressure plasma jet treated micro-structured titanium surfaces

The previous study has shown that the treatment of nitrogen-based non-thermal atmospheric pressure plasma jet (NTAPPJ) on titanium (Ti) surface resulted in promoted cell attachment. Nonetheless, essential understanding on enhanced cell-material interaction with NTAPPJ-treated surface and consequent differentiation of cell on the biomaterial is insufficient. Therefore in this study, effects of NTAPPJ on integrins, that play a fundamental role in regulating the activation of signaling pathways as well as adhesion of cell-material interactions, have been investigated. The Ti samples were exposed to NTAPPJ, where control samples were unexposed to NTAPPJ. The formations of chemical function groups on surface of Ti samples were investigated with X-ray photoelectron spectroscopy. Human plasma fibronectin (FN) adsorption was analyzed by protein assay kit and spectrophotometer. Also, for the investigation of specific gene expression of integrin subunits and osteoblast phenotype genes expression of MC3T3-E1 cells, quantitative PCR was carried out. The results showed that FN adsorption and gene expression levels of integrin subunits α₅, β₁ and β₃, and osteocalcin were significantly higher with cells cultured on NTAPPJ-treated samples. Therefore it was concluded that the cell differentiation along with the adhesion between cells and Ti biomaterials were promoted with NTAPPJ due to the improved integrin activation following the improved protein adsorption. Such results are expected to provide better understanding in application of NTAPPJ on biomaterials.