Fabrication, modification, and biomedical applications of anodized TiO2 nanotube arrays

Titanium dioxide (TiO2) nanotubes have attracted increasing attention due to their outstanding properties and potential applications in photocatalysis, dye-sensitized solar cells, and biomedical devices. In this paper, recent research progress on TiO2 nanotube arrays (NTAs) produced by anodic oxidation of Ti in fluoride- containing electrolytes is reviewed with emphasis on the modification methods and biomedical applications. The fabrication protocol and growth mechanism are first discussed and common modification methods used to improve the optical, electronic, and biomedical properties of TiO2 NTAs are reviewed. Photo/electro-chemical biosensors based on TiO2 NTAs dedicated to the detection of glucose, hydrogen peroxide, and other biomolecules are described and recent examples of using TiO2 NTAs to improve the cellular response in vitro and accelerate osseointegration in vivo are provided. The incorporation and delivery of inorganic bioactive agents such as Ag, Sr, and Zn to achieve antibacterial and/or osteogenesis inducing ability are described and finally, the outlook and future development of TiO2 nanotubes pertaining to biomedical devices are briefly discussed.