Towards development of chemosensors and biosensors with metal-oxide-based nanowires or nanotubes

The emerging nanotechnology has opened new exciting opportunities to explore analytical applications of the freshly prepared nanostructured materials. Among them, metal-oxide-based nanowires or nanotubes attracted great attention due to their one-dimensional (I D) morphology, extraordinary physical and chemical properties, which offer great promise in the development of chemical sensing or biosensing, facilitating the great improvement of the selectivity and sensitivity of the current methods. In this review, the recent advances in the development of sensors including gas sensors, humidity sensors, and immunosensors using semiconducting metal-oxide-based nanowires or nanotubes are highlighted. Titanate (H2Ti3O7) nanotubes are of multilayered structures with a nanometer-scale inner-core cavity exposed to the outer surface and display different oxidation states with possible redox-activity, which make them attractive for sensing. Therefore, the use of titanate nanotubes for the development of electrochemical sensors is overviewed. Finally, the prospects and challenge in the further exploration of nanoscaled sensors are discussed. (C) 2008 Elsevier B.V. All rights reserved.