Enhancement of in vitro osteogenesis on titanium by chemically produced nanotopography

The surface characteristics of biornaterials can influence protein adsorption, cellular functions, and ultimately tissue formation. Controlled chemical oxidation of titanium-based surfaces with a mixture of H2SO4/H2O2 creates a nanopatterned surface that has been shown to affect early osteogenic events. The objective of this study was to evaluate the effect over time of this nanopattern on various key parameters of osteogenesis, and determine whether these effects ultimately translate into more mineralized matrix production. Osteogenic cells were obtained by enzymatic digestion of newborn rat calvaria and grown on treated and untreated titanium discs for periods of up to 14 days. Alkaline phosphatase activity peaked earlier and cell number was higher as of day 7 on the nanopatterned discs. Immunofluorescence showed that the treated surface favored early bone sialoprotein and osteopontin secretion, and fibronectin accumulation. Alizarin red staining revealed that, at days 10 and 14, there were significantly more mineralized nodules on treated than on untreated discs. These results demonstrate that simple chemical treatment of titanium with H2SO4/H2O2 accelerates the in vitro osteogenic potential of calvaria-derived cells. They also suggest that this treatment may represent an advantageous approach for producing "intelligent surfaces" that stimulate bone formation and enhance bone-implant contact. (c) 2006 Wiley Periodicals, Inc.