Influence of engineered titania nanotubular surfaces on bone cells

Abstract

A goal of current orthopedic biomaterials research is to design implants that induce controlled, guided, and rapid healing. In addition to acceleration of normal wound healing phenomena, these implants should result in the formation of a characteristic interfacial layer with adequate biomechanical properties. To achieve these goals, however, a better understanding of events at the bone–material interface is needed, as well as the development of new materials and approaches that promote osseointegration. Using anodization, titania interfaces can be fabricated with controlled nanoarchitecture. This study demonstrates the ability of these surfaces to promote osteoblast differentiation and matrix production, and enhance short- and long-term osseointegration in vitro. Titania nanotubular surfaces were fabricated using an anodization technique. Marrow stromal cells (MSCs) were isolated from male Lewis rats and seeded on these surfaces along with control surfaces. The interaction of cells with these surfaces was investigated in terms of their ability to adhere, proliferate and differentiate on them. The experiments were repeated three times with cells from different cultures. All the results were analyzed using analysis of variance (ANOVA). Statistical significance was considered at p<0.05. Furthermore, in vivo biocompatibility was assessed by implanting surfaces subcutaneously in male Lewis rat and performing histological analysis after 4 weeks. Our results indicate that the nanotubular titania surfaces provide a favorable template for the growth and maintainence of bone cells. The cells cultured on nanotubular surfaces showed higher adhesion, proliferation, ALP activity and bone matrix deposition compared to those grown on flat titanium surfaces. In vivo biocompatibility results suggest that nanotubular titania does not cause chronic inflammation or fibrosis. The fabrication routes of titania nano-architectures are flexible and cost-effective, enabling realization of desired platform topologies on existing non-planar orthopedic implants.