INTRODUCTION: Surface modification of titanium by coating with natural bioactive polymers, has been suggested as a means to improve osseointegration in dental implantology applications. Wool‐derived keratin, due to its demonstrated ability to promote bone formation, has been suggested as such a potential bioactive material. As limited knowledge is available on the biological effects of keratin on osteoblasts, the aim of this study was to assess the effects of two novel methodologies used to coat titanium surfaces with keratin, on osteoblast function.

METHODS: Titanium was silanized with APTES and crosslinked with glutaraldehyde to facilitate covalent binding with keratin. Two keratin‐coated titanium surfaces were fabricated via solvent casting (Ti‐KC) and functionalization (Ti‐KF) respectively. The attachment, proliferation, viability and cellular morphology of MG‐63 osteoblast cells cultured on these modified surfaces were determined by semi‐automated quantitative microscopy. The osteogenic effect of the modified surfaces on osteocalcin (OCN), osteopontin (OPN), alkaline phosphatase (ALP), runt‐related transcription factor 2 (RUNX2), Collagen Type I (COL1) and bone morphogenetic protein‐2 (BMP2) gene expression was investigated by quantitative PCR.

RESULTS: MG‐63 proliferation over 14 days on the Ti‐KF surface was the same as on uncoated titanium. On the Ti‐KC surface, proliferation initially lower at days 1 and 7 was similar to control levels by day 14. No significant differences in cell viability were seen. Elongated spindle‐shaped cells were seen on functionalized and untreated titanium on day 1, whereas oval‐shaped cells were noted on the coated surface. Over time in culture however, MG‐63 cells on all surfaces became spindle shaped with no statistical difference in morphological measurements. Osteogenic gene expression on the modified surfaces was higher compared to uncoated titanium at all times. While a similar temporal gene expression over the 14 days was noted on both surfaces, osteocalcin (OCN) expression on the Ti‐KC surface was significantly increased over the first three days compared with that on the Ti‐KF surface. OPN, ALP, RUNX2, COL1 and BMP2 gene expression was similar on either coating.

DISCUSSION & CONCLUSIONS: The surface topography and chemistry of biomaterials is known to influence a wide range of biological responses such as cell migration, adhesion, proliferation, and differentiation in adherent cells. This study showed that covalently bound keratin on titanium surfaces did not have any lasting negative impacts on MG‐63 cell attachment, morphology or subsequent proliferation. Improved osteogenic gene expression in MG‐63 cells as a result of keratin coating suggests this surface may be useful in bone‐implant applications.