Ultrathin TiO₂ Coatings via Atomic Layer Deposition Strongly Improve Cellular Interactions on Planar and Nanotubular Biomedical Ti Substrates

Abstract

This work aims to investigate the chemical and/or structural modification of Ti and Ti-6Al-4V (TiAlV) alloy surfaces to possess even more favorable properties toward cell growth. These modifications were achieved by (i) growing TiO 2 nanotube layers on these substrates by anodization, (ii) surface coating by ultrathin TiO 2 atomic layer deposition (ALD), or (iii) by the combination of both. In particular, an ultrathin TiO 2 coating, achieved by 1 cycle of TiO 2 ALD, was intended to shade the impurities of F-and V-based species in tested materials while preserving the original structure and morphology. The cell growth on TiO 2 -coated and uncoated TiO 2 nanotube layers, Ti foils, and TiAlV alloy foils were compared after incubation for up to 72 h. For evaluation of the biocompatibility of tested materials, cell lines of different tissue origin, including predominantly MG-63 osteoblastic cells, were used. For all tested nanomaterials, adding an ultrathin TiO 2 coating improved the growth of MG-63 cells and other cell lines compared with the non-TiO 2 -coated counterparts. Here, the presented approach of ultrathin TiO 2 coating could be used potentially for improving implants, especially in terms of shading problematic F-and V-based species in TiO 2 nanotube layers.