Recombinant Human Bone Morphogenic Protein-2 (Rhbmp-2) Immobilization onto the Surface of Apatite-Coated Titanium Significantly Promotes Osteoblast Function and Mineralization

Abstract

Titanium (Ti) has been widely used in the dental field owing to its good biocompatibility, superior mechanical properties, and excellent corrosion resistance. However, Ti lacks the osteoconductivity and osteoinductivity required to promote mineralization. In the present study, the authors investigated whether apatite-coated Ti and rhBMP-2 treated apatite-coated Ti promote more mineralization than pristine Ti. Characterizations of pristine Ti, apatite-coated Ti, or rhBMP-2/apatite-coated Ti were analyzed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). In addition, the release profile of rhBMP-2 from rhBMP-2/apatite-coated Ti was monitored for 28 days, and the biocompatibility of pristine Ti, apatite-coated Ti, and rhBMP-2/apatite-coated Ti was evaluated by measuring cell proliferation, alkaline phosphatase (ALP) activity, calcium deposition, and real-time PCR using MG-63 cells. SEM, EDS, and ATR-FTIR showed that the apatite on apatite-coated Ti surfaces was similar to that of natural bone. Furthermore, rhBMP-2 appeared to be released steadily over 28 days from rhBMP-2/apatite-coated Ti, and MG-63 cells grown on rhBMP-2/apatite-coated Ti showed significantly higher proliferation activity, ALP activity, and calcium deposition compared to MG-63 cells grown on pristine Ti or apatite-coated Ti. Furthermore, osteocalcin and osteopontin gene expression in MG-63 cells grown on rhBMP-2/apatite-coated Ti was significantly greater than that in MG-63 cells grown on pristine Ti or apatite-coated Ti by real-time PCR. Taken together, rhBMP-2/apatite-coated Ti substrate has enhanced osteoblast function and mineralization. Thus, rhBMP-2/apatite-coated Ti may be a more effective substrate than pristine Ti used in the dental field.