Enhancement of electro-chemical properties of TiO2 nanotubes for biological interfacing.

Micro/nano electrodes employing nanotubes has attracted paramount attention in recent years due to their inherent superior mechanical and structural properties. Electrical interfaces with different geometries and sizes have been developed as electrodes for measuring action potentials and investigating neural information processing in neural networks. In this work, we investigated the possibility of using TiO2 nanotube arrays that were grown using electrochemical anodization technique, as a micro/nano electrode for neural interfacing. The morphology of fabricated nanotube arrays were found to be significantly affected by the applied voltage. Annealing and doping of TiO2 nanotube arrays has been performed to improve the structural and electrical properties of the nanotube arrays. It was found that the annealing and doping with nitrogen improve the electrical conductivity of the nanotube arrays. Moreover, the tube diameter and length can be controlled by changing the applied voltage and that can significantly affect the biocompatibility of the nanotube arrays. It was observed that nitrogen doped nanotubes with morphology consisting of 61nm diameter, 25nm wall thickness and tube length of 2.25µm could be good candidate to be used as electrodes for biological interfacing. This is due to the fact that the nitrogen doped nanotubes with aforementioned morphology possess great properties necessary for effective biological interfacing such as low impedance, high capacitance and good biocompatibility.

Anodization parameters influencing the morphology and electrical properties of TiO2 nanotubes for living cell interfacing and investigations.

Nanotube structures have attracted tremendous attention in recent years in many applications. Among such nanotube structures, titania nanotubes (TiO2) have received paramount attention in the medical domain due to their unique properties, represented by high corrosion resistance, good mechanical properties, high specific surface area, as well as great cell proliferation, adhesion and mineralization. Although lot of research has been reported in developing optimized titanium nanotube structures for different medical applications, however there is a lack of unified literature source that could provide information about the key parameters and experimental conditions required to develop such optimized structure. This paper addresses this gap, by focussing on the fabrication of TiO2 nanotubes through anodization process on both pure titanium and titanium alloys substrates to exploit the biocompatibility and electrical conductivity aspects, critical factors for many medical applications from implants to in-vivo and in-vitro living cell studies. It is shown that the morphology of TiO2 directly impacts the biocompatibility aspects of the titanium in terms of cell proliferation, adhesion and mineralization. Similarly, TiO2 nanotube wall thickness of 30-40nm has shown to exhibit improved electrical behaviour, a critical factor in brain mapping and behaviour investigations if such nanotubes are employed as micro-nano-electrodes.