The enhanced effect of surface microstructured porous titanium on adhesion and osteoblastic differentiation of mesenchymal stem cells

Porous titanium with appropriate surface treatments can be osteoinductive. To investigate the effect of surface treatments of porous titanium on the attachment and differentiation of mesenchymal stem cells (MSCs), two kinds of surface microstructured porous titaniums, H2O2/TaCl5 treated one (HTPT), and H2O2/TaCl5 and subsequent simulated body fluid (SBF) treated one (STPT) were fabricated, and non-treated one (NTPT) was used as control. The morphology, specific surface area (SSA), pore distribution and mechanical strength of these materials were characterized respectively, and the results showed that H2O2/TaCl5 treatment led to a significant increase in both SSA and micropores of HTPT, and the further SBF immersion resulted in the formation of a layer of bone-like apatite on the surface of STPT. Although the surface treatments had a little negative impact on the compressive strength and elasticity modulus of porous titanium, the mechanical strength of HTPT or STPT was enough for the bone defect repair of the load-bearing sites. The protein adsorption and cell adhesion experiments confirmed that the microstructured surface notably enhanced porous titanium's protein binding capacity and promoted MSCs adhesion on the surface. More importantly, cell differentiation experiments proved that the microstructured surface evidently elevated the osteoblastic gene expressions of MSCs compared to NTPT. The enhanced biological effect by the surface treatments was more robust on STPT. Therefore, our results suggest that the microstructured surface has great potential for promoting MSCs differentiation towards osteoblasts, giving excellent support for the osteoinduction of porous titanium with appropriate surface treatments.