Enhanced osteoblast functions on RGD immobilized surface.

Many methods are currently under investigation to improve the integration of dental implants to surrounding bones. Among these methods, peptide-modified surfaces have been highlighted as one of the most promising. Our study, aimed at the cellular response to RGD-immobilized surface in vitro, investigated the basis for designing a bone-active surface coating with RGD-containing peptide. Gold-coated titanium surfaces were used as indicative control surfaces for peptide immobilization. Using self-assembly monolayer techniques, 2 types of peptides, RGDC (Arg-Gly-Asp-Cys) and RDGC (Arg-Asp-Gly-Cys), were immobilized onto the gold surfaces. Surface justification was realized through X-ray photoelectron spectroscopy and Fourier transform infrared spectra. Primary calvarial osteoblasts were cultured on RGDC, RDGC, and non-peptide-coated surfaces. Cell attachment, morphology, proliferation, and expression of osteocalcin (OC) messenger RNA (mRNA) were assessed using cell counting, immunolabeling fluorescence microscopy, and Northern blot assay. Four and 8 hours after culture, cell attachment was enhanced on RGDC surfaces. Correspondingly, increased cell spreading and significantly greater cell proliferation were also observed in cells grown on the RGDC-coated surfaces. More importantly, osteoblasts on RGDC surfaces showed earlier and significant OC mRNA expression at day 15 compared with controls having the similar expression at day 21. These results provided evidence of the enhanced functions of osteoblasts cultured on the RGDC-modified surfaces, which might be effective in improving osseointegration for dental implants.