Morphology control in oxygen-rich nanotubular titania for enzyme-free glucose detection

The necessity of research in food and nutrition and the emergence of diabetes mellitus call for fast and efficient glucose detection. Here, series of highly sensitive non-enzymatic photoelectrochemical glucose sensor based on engineered titanium dioxide nanotube arrays has been synthesized using a simple electrochemical approach to tune nanotubes morphology in a way that the highest sensitivity factor (525.5 µAmM⁻¹cm⁻²) and saturation concentrations (0.18 mM) achieved in the photoelectrochemical sensor. The formation of oxygen-rich titanium oxide was confirmed by several techniques. Dependent on the growth condition, nanotube length changed from 1.9 to 8.4 µm while their inner diameter varied from 78 to 156 nm. According to the results, TiO₂ nanotube arrays anodized for 4 h at 60 V presented the highest saturation concentration of 0.18 mM, which can be used for high glucose level demand cases. On the other hand, nanotubes anodized for 6 h at 50 V obtained the highest sensitivity factor of 525.5 µAmM⁻¹cm⁻² with an excellent detection limit and saturation level of 0.1 mM, which is beneficial for purposes involving slight changes in analyte amount. Both optimized sensors presented reasonable selectivity and stability providing optimum tubular TiO₂ nanostructure morphology for developing non-enzymatic photoelectrochemical sensors.