Enhanced osteogenic differentiation of bone mesenchymal stem cells on magnesium-incorporated titania nanotube arrays.

Although titanium and its alloys have been widely used as implants in orthopaedics and dentals, it is still a challenge to realize excellent bioactivity of titanium surface. In this report, magnesium ion incorporated titania nanotube arrays (MgNT) was fabricated on Ti surface through electrochemical anodization and hydrothermal treatment. The magnesium loading capacity and release kinetics were controlled by modulating the conditions in the hydrothermal treatment process. The surface morphology and composition characterized by SEM, TEM, and XPS indicated that magnesium was incorporated into nanotube in the form of MgTiO3. Bone mesenchymal stem cells (BMSCs) showed accelerated proliferation rate on MgNT surfaces and extended more microfilaments than that on Ti surface. The mRNA expressions of osteogenic related genes (ALP, Col-І, OCN, and RUNX2) and angiogenic related genes (HIF-2α and VEGF), and the OCN protein expression were all significantly up-regulated on MgNT surfaces. Moreover, the ERK1/2 signaling pathway was activated on MgNT surface. All the results demonstrated that MgNT surfaces enhanced the osteoinductive activity of Ti implants through ERK signaling pathway. This strategy is promising for improving the bioactivity of Ti implants and facilitating its clinic application.