Photoelectrochemical sensing of titanium oxide nanostructures for the detection of glucose: Fabrication methods and signal enhancement strategies

Abstract

The development of ultrasensitive sensors with excellent selectivity is a persistent challenge in the field of sensors and biosensors. Increasing the sensitivity of sensors can allow enhanced detection of crucial analytes such as glucose. Sufficient sensitivities can enable non-invasive methods for glucose detection in biological environments such as saliva, sweat, and tears. In this regard, the integration of electrochemical and optical methods as photoelectrochemical (PEC) (bio)sensors is a beneficial endeavour toward increased sensitivity. The materials that compose PEC sensors including metals, polymers, and metal oxides can confer variable PEC properties. An interesting photoactive material is titanium oxide (TiO2). TiO2 has been prominently supported in the field of PEC (bio)sensors, especially regarding glucose detection. Numerous studies have been conducted based on surface and property modifications of this material to increase its PEC behaviour. The modifications aim to enhance the photo absorbance of TiO2 and thus increasing the efficiency and sensitivity of the semiconductor as a PEC glucose sensor. Various types of TiO2 nanostructures, including nanoparticles, nanorods, nanowires, nanotubes, and nanosheets have recently been used for glucose detection as a PEC (bio)sensor. This review seeks to provide a detailed summary of TiO2 nanostructures, their fabrication methods, and PEC signal enhancement to demonstrate and discuss how to improve PEC glucose sensing. This study represents cutting-edge innovation, focusing on continual development to resolve existing disadvantages in bare TiO2 and strive for optimal PEC glucose detection.