Nanochannels formed on TiZr alloy improve biological response

In the present work we report the fabrication of non-thickness-limited 1D nanostructures with nanochannelar structure by anodization of Ti50Zr alloy in hot glycerol-phosphate electrolyte. These nanochannelar structures show high and adjustable aspect ratios and provide as-formed already partial crystallinity for nanochannels. In vitro studies were performed to assess the inflammatory response to nanochannel coated surfaces using RAW 264.7 macrophages. The results show that these nanochannels yield a reduced amount of metabolically-active macrophages, low potential to induce macrophage fusion into FBGC, and low concentration of pro-inflammatory cytokines in the culture medium. Moreover, higher hydrophilicity and lower corrosion rates were registered, compared to compact oxide. Collectively, the results indicate a more favorable cellular response on such nanoscale topography as compared to compact oxide control substrate, and suggest that surface architecture design of nanochannel type on implant materials holds promise for biomedical applications.

Statement of significance: The use of titanium and its alloys in biomedical devices has been extensively investigated, especially for alloys possessing inherent antibacterial properties such as TiZr alloys. We report for the first time the growth of mesoporous structures, aligned oxide nanochannels, on Ti50Zr alloy. The advantages of these nanochannelar surfaces are a high surface area, a long range ordered nanoscale topology and already partial crystallinity in the as-grown state. In vitro studies performed on RAW 264.7 macrophages demonstrate the potential of nanochannels to lower the inflammatory response, thus reducing the foreign body reaction against Ti50Zr biomedical implants and promoting the successful integration of the implant.