(1168-A) Initial osteoblast cell response to keratin-coated titanium.

Abstract:

Introduction: Surface modification of titanium is performed to improve its bioactivity and bone healing in dental applications. Wool-derived keratin has been suggested as a potential bioactive material for implant surfaces, due to its ability to promote bone formation. The surface topography of biomaterials has been found to influence a range of biological responses such as cell migration, adhesion, proliferation, and differentiation. Cell morphology and adhesion provide an insight of the material and cellular interactions at the implant site. The aim of this study was to assess the effects of a novel keratin-coated titanium surface on osteoblasts following attachment.

Methods: For this purpose, titanium was silanized with APTES and crosslinked with glutaraldehyde to facilitate the covalent binding of keratin. Two keratin-coated titanium surfaces were fabricated via either solvent casting or molecular grating. MG-63 osteoblast cells were cultured on these keratin-modified surfaces, with untreated titanium as a control. The nature of the attachment of MG-63 osteoblast cells cultured on untreated titanium and modified surfaces along with their effect on osteogenic gene and protein expression were quantified in vitro. Automated image analysis protocols were used to determine MG-63 cell responses using Cell Profiler.

Results: No significant effect on MG-63 proliferation or viability with culture on keratin-coated titanium was noted. Scanning electron and fluorescence microscopy analyses exhibited poor cell adhesion on the solvent-cast titanium surface at the initial time point. The cells cultured on solvent-cast titanium surface showed more pronounced oval-shaped cells with smaller cell area, diameter, perimeter with larger aspect ratio, and form factor than those cultured on the molecular grafted titanium surface and control. Over time in culture, however, MG-63 cells on all surfaces became spindle-shaped with no statistical difference in morphological measurements. Osteogenic gene expression was similar on both coated surfaces at all timepoints while significantly higher expression of osteogenic proteins osteopontin and osteocalcin were observed on the keratin-coated titanium surfaces.

Conclusions: This study showed that covalently bound keratin on titanium substrates has positive impacts on MG-63 cell attachment, morphology, or subsequent proliferation. Improved osteogenic protein expression in MG-63 cells as a result of culture on keratin-coated titanium suggests these surfaces may be useful in bone-implant applications.