Effect of TiO2 nanotubes size, heat treatment, and UV irradiation on osteoblast behavior

Titanium implants have been extensively used in orthopedic and dental applications due to their high performance at the biomechanical level and their excellent biocompatibility. Currently, in bone implants, the design of surfaces is used to address a biological behavior that includes the improvement of osseointegration or the immobilization of active molecules. This paper aimed to describe the effect of the nanotube characteristics on the adhesion, proliferation, and mineralization of osteoblasts. To the best of our knowledge, the effect of reduced internal diameters (≈10 nm) with and without UV irradiation and with and without heat treatment on osteoblast adhesion, proliferation, and mineralization has not been reported. All the anodic coatings were biocompatible; however, surface characteristics such as topography, wettability, charge, and phase composition could affect osteoblast adhesion, proliferation, and mineralization. Nanotubular coatings with higher roughness and UV irradiation improved early cell adhesion; however, the nanotubes with a diameter of about 10 nm and composed entirely by rutile or anatase phases negatively affected early cell adhesion. The number of filopodia rises with the reduction in the internal diameter of the porous anodic coating, and the mineralization had the same behavior, namely: a decrease of the internal diameter induced a superior rate of matrix mineralization.