Metal Oxide-based Electrochemical Non-enzymatic Glucose Biosensors: A Mini-Review

Electrochemical glucose-sensing devices have advanced significantly in recent years, driven by the rising prevalence of diabetes mellitus, which is projected to become the seventh leading cause of death by 2030. The surge in the number of diabetes cases has accelerated the development of high-sensitivity and high-selectivity glucose biosensors. Traditional enzy-matic glucose biosensors based on glucose oxidase or glucose dehydrogenase have evolved over multiple generations to over-come challenges, such as oxygen dependence, mediator toxicity, and enzyme instability. The latest fourth-generation glucose biosensors utilize metal-oxide-based catalysts instead of biological enzymes, offering enhanced stability, sensitivity, and cost-effectiveness. Nanoparticles (NPs) of metal oxides such as NiO, CuO, and Co₃O₄ exhibit high electrocatalytic activity and redox stability, making them promising materials for non-enzymatic glucose sensing. This review explores the recent advancements in metal oxide-based non-enzymatic glucose biosensors, particularly those employing NiO, CuO, and Co₃O₄ NPs, with a focus on electrocatalytic mechanisms, material innovations, and sensor fabrication strategies. Additionally, it highlights the current limitations and challenges of metal oxide-based glucose biosensors, while examining their potential applications in continuous glucose monitoring and wearable biosensors.