BM-MSC Adhesion and Differentiation Increase by Oxidized Nano-Structured Titanium Surfaces

Objectives: to characterize the micro- and nano-texture of a novel oxidized titanium implant surface with respect to a conventional turned one, and to evaluate their ability to affect the response of human bone marrow mesenchymal stem cell (BM-MSC) in terms of adhesion, proliferation and osteogenic differentiation. Methods: 10x10x1 mm turned (control) and oxidized (test) titanium samples (P.H.I. s.r.l., San Vittore Olona, Milano, Italy) were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM) and characterized by different roughness parameters at different dimensional analysis ranges. Primary cultures of BM-MSC were seeded on titanium samples and cell morphology, adhesion, proliferation and osteogenic differentiation, in terms of alkaline phosphatase activity, osteocalcin synthesis and extracellular matrix mineralization, were evaluated. Results: oxidized surfaces showed a more complex micro- and nano-scaled texture with respect to turned ones at both SEM and AFM analyses, with higher values of roughness parameters at different analysis ranges. Also cell adhesion and early and late osteogenic parameters were greater on oxidized (p<0.05 at least) vs turned surfaces, whereas the cell proliferation rate was similar. Conclusions: Both control and test samples were in the “smooth” range of average roughness, but they exhibited significantly different topographic properties, which could be properly characterized only using a multi-range/multi-parameter approach and proper filtering procedures. This different micro- and nanostructure resulted in an enhanced adhesion and differentiation of cells cultured onto the oxidized surfaces.