Enhanced Performance of Osteoblasts by Silicon Incorporated Porous TiO2 Coating

Silicon (Si) incorporated porous TiO2 coating (Si-TiO2) prepared on titanium (Ti) by micro-arc oxidation (MAO) technique was demonstrated to be cytocompatible in previous studies. In view of the potential clinical applications, a detailed in vitro study of the biological activity of Si-TiO2 coating, in terms of osteoblast (MC3T3-E1 cells) morphology, proliferation, differentiation and mineralization was performed. Immunofluo-rescent staining indicated that cells seeded on the Si-TiO2 coating showed improved adhesion with developing mature cytoskeletons, which contained numerous distinct and well-defined actin stress fibers in the cell mem-branes compared with those on the TiO2 coating and Ti plate. Results from proliferation assay showed that the proliferation rate of cells seeded on the Si-TiO2coating was significantly faster than that on the TiO2 coating and Ti plate. Furthermore, the analysis of osteogenic gene expression demonstrated that the Si-TiO2 coating stimulated the expression of osteoblast-related genes and promoted differentiation and mineraliza-tion of MC3T3-E1 cells. In addition, the Si-TiO2 coating differentially regulated Wnt signaling pathway by up-regulating the expression of low-density lipoprotein (LDL) receptor-related protein 5 (Lrp5), and down-regulating the expression of Dickkopf-1 (Dkk1). All together, these results indicate that the investigated titanium with Si-TiO2 coating is biocompatible and a good candidate material used as implants