Effects of hydrogenated TiO(2) nanotube arrays on protein adsorption and compatibility with osteoblast-like cells

BACKGROUND: Modified titanium (Ti) substrates with titanium dioxide (TiO(2)) nanotubes have broad usage as implant surface treatments and as drug delivery systems. METHODS: To improve drug-loading capacity and accelerate bone integration with titanium, in this study, we hydrogenated anodized titanium dioxide nanotubes (TNTs) by a thermal treatment. Three groups were examined, namely: hydrogenated TNTs (H(2)-TNTs, test), unmodified TNTs (air-TNTs, control), and Ti substrates (Ti, control). RESULTS: Our results showed that oxygen vacancies were present in all the nanotubes. The quantity of -OH groups greatly increased after hydrogenation. Furthermore, the protein adsorption and loading capacity of the H(2)-TNTs were considerably enhanced as compared with the properties of the air-TNTs (P<0.05). Additionally, time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to investigate the interactions of TNTs with proteins. During the protein-loading process, the H(2)-TNTs not only enabled rapid protein adsorption, but also decreased the rate of protein elution compared with that of the air-TNTs. We found that the H(2)-TNTs exhibited better biocompatibility than the air-TNT and Ti groups. Both cell adhesion activity and alkaline phosphatase activity were significantly improved toward MG-63 human osteoblast-like cells as compared with the control groups (P<0.05). CONCLUSION: We conclude that hydrogenated TNTs could greatly improve the loading capacity of bioactive molecules and MG-63 cell proliferation.