Horseradish peroxidase/graphene electrochemical biosensor for glutathione detection

Abstract

Glutathione (GSH) is a tripeptide composed of three amino acids: cysteine, glycine, and glutamate. It is essential to many different living things as an antioxidant. GSH serves as a key biomarker and its detection is crucial for studying its levels in living bodies, providing insights into various diseases. In this work, we present the use of a highly sensitive electrochemical sensor to detect GSH utilizing a graphene oxide (GO)–modified indium tin oxide (ITO) electrode immobilized with the enzyme horseradish peroxidase (HRP). The modified electrode was further characterized by Fourier transform infrared spectroscopy, and the spectrum showed that HRP was successfully immobilized onto GO. The electrochemical behavior of the modified ITO was examined by cyclic voltammetry. Cyclic voltammetry demonstrated HRP/GO/ITO electrode has better electrocatalytic activity than bare ITO in the oxidation of GSH in acetate buffer solution. The electrochemical sensor had a 1 µM detection limit and a linear range of 10 to 50 µM. The HRP/GO/ITO electrode resulted in improved electrocatalytic properties, long-term stability, good repeatability, and high sensitivity, and it has a quick response to detect GSH. In addition, GSH concentration in real sample was measured using the HRP/GO/ITO-modified electrode.