Cytompatibility assessment of the surface of titanium after phosphorylation

In this study, orthophosphoric acid (H3PO4) in the treatment of porous titanium (Ti) is investigated and the ability of rat bone marrow stromal cells (BMSCs) is assessed to proliferate and differentiate on these modified surfaces in vitro. To improve the cytocompatibility of Ti surfaces, pure Ti was activated commercially by simple chemical pretreatment in H3PO4 with different densities. Next, the phosphorylated specimens were soaked in simulated body fluid (SBF) to study the effect of biomineralization. The3-[4,5-dimethylthiazol-2-y1]-2, 5-diphenytetrazolium bromide (MTT) assay and the measurement of alkaline phosphatase (ALP) activity utilized to assess proliferation and differentiation of BMSCs on exposure to modified Ti surfaces. Scanning electron microscopic (SEM) images showed that the surfaces of the pre-treated samples were characterized by a complex structure which consisted of a mesh-like morphological matrix and an uniform surface with different morphic crystals of titanium dihydrogen orthophosphate (Ti(H2PO4)3). These crystals contained hydroxyl with phosphate residues that resulted in biomineralization of cells. Therefore, BMSCs reveales a well-dispersed morphology on these modified and functionalized Ti surfaces. The viability and ALP activity of BMSCs on these altered biomimetic surfaces are found to be greater than those of the controls. It is concluded that the treatment of Ti by acid etching in orthophosphoric acid is a suitable method to enhance the in vitro proliferation and differentiation of BMSCs.