Enhanced osteogenic differentiation of MC3T3-E1 on rhBMP-2-immobilized titanium via click reaction

•Click chemistry is a good method to conjugate BMP-2 on Ti surface.•BMP-2 well-controllably released for 28 days.•Ti-6 was a useful tool to enhance the osteogenesis of MC3T3-E1. In the present study, we report about the efficacy of titanium surface-immobilized with bone morphogenetic protein-2 (BMP-2) via click reaction on enhanced osteogenic differentiation of MC3T3-E1 cells. The surface was characterized by static contact angles and XPS measurements, which indicated that pristine titanium (Ti-1) was successfully surface-modified via click chemistry (aminated titanium, Ti-4). By quantitative analysis of heparin immobilized on aminated titanium (Ti-4), we found that the Ti-4 can be used as a good candidate to immobilize biomolecules such as heparin. BMP-2 from titanium immobilized with BMP-2 (Ti-6) was released for a period of 28 days in a sustained manner. The highest proliferation rate of MC3T3-E1 cells was observed on Ti-6. Through in vitro tests including alkaline phosphatase (ALP) activity, calcium deposition and real-time polymerase chain reaction (real-time PCR), we found that Ti-6 can be used as a good implant to enhance the osteogenic differentiation of MC3T3-E1 cells.