Self-organized high-aspect-ratio TiO2 nanotubular layers exhibit excellent photocatalytic properties that are significantly enhanced compared to nanoparticulate layers. These tubular layers have showed remarkable photocatalytic activity for the decomposition of organic azo dyes namely, Acid Organge 7 (AO7) and Methylene Blue (MB), which are non-biodegradable dyes used in the textile industry and often considered as standard dyes for testing photocatalytic activity. Crystalline structure of TiO2 tubes, is a critical factor for good catalytic performance of these tubes at the liquid-solid interface. The use of such tubular layers is potentially suitable in applications where the particle separation from the cleaned media is technologically expensive and difficult. For biological uses, the tubes can be grown on biomedical Ti alloys, and can be used as a seed layer for hydroxyapatite formation.