Enhanced Biocompatibility in Anodic TaO(x) Nanotube Arrays

This study first investigates the biocompatibility of self-organized TaO(x) nanotube arrays with different nanotube diameters fabricated by electrochemical anodization. All as-anodized TaO(x) nanotubes were identified to be an amorphous phase. The transition in surface wettability with TaO(x) nanotube diameters can be explained based on Wenzel’s model in terms of geometric roughness. In vitro biocompatibility evaluation further indicates that fibroblast cells exhibit an obvious wettability-dependent behavior on the TaO(x) nanotubes. The 35-nm-diameter TaO(x) nanotube arrays reveal the highest biocompatibility among all samples. This enhancement could be attributed to highly dense focal points provided by TaO(x) nanotubes due to higher surface hydrophilicity. This work demonstrates that the biocompatibility in Ta can be improved by forming TaO(x) nanotube arrays on the surface with appropriate nanotube diameter and geometric roughness.