(358g) Copper Functionalized TiO2 Nanotube Sensors for Enhanced Rapid Glutathione Sensing

Oxidative stress is a physiological state characterized by excess levels of strong electron acceptors known as reactive oxygen species (ROS). Oxidative stress is associated with a number of human diseases, and may also result from exposure to hazardous chemicals. Because ROS are potentially damaging to cells, the human body uses endogenous antioxidants to control ROS concentration and maintain homeostasis. One of the most important endogenous antioxidants is a thiolated polypeptide known as glutathione. Glutathione in its reduced form (GSH) readily undergoes redox reactions that consume ROS and oxidize glutathione. Oxidized glutathione molecules thus produced link via covalent disulfide bridges, thereby forming glutathione dimers (GSSG). Hence the ratio of GSSG to GSH in various body fluids may be used as an indicator of oxidative stress. Here, we demonstrate proof-of-concept of a low-cost glutathione sensing platform that uses copper functionalized titanium dioxide nanotubes (Cu-TiO₂-NTs) to bind glutathione, and uses cyclic voltammetry (CV) to detect glutathione adsorption. Glutathione binding (GSH or GSSG) to the nanotubes is detected as a minimum in the current during a CV scan at -300 mV. The amplitude of this current minimum is larger for Cu-TiO₂ NTs than for bare TiO₂-NTs (3.18 times larger for GSH, and 1.71 times larger for GSSG). Our results demonstrate proof-of-concept for the use of copper functionalized TiO₂-NTs in a low-cost glutathione sensor.