Enhanced Glucose Sensing through Optimization of Glucose Oxidase and Osmium-Based Redox Polymers on Gold Electrodes

Glucose oxidase (GOx)-based electrodes are widely employed in glucose sensors and present potential as power sources for implantable devices. The osmium-based redox polymer plays a crucial role in improving electron transfer between the enzyme’s active sites and the electrode surface. This study aimed to identify the optimal loading and ratio of GOx to poly (N-vinylimidazole)-[Os(4,4′-dimethyl-2,2′-bipyridine) ₂ Cl]) ^+/2+ (PVI-Os-dme) to enhance the functional performance of GOx electrodes. Increasing both GOx and PVI-Os-dme loadings resulted in enhanced current output, underlining the importance of achieving balance between the catalytic reaction rate and electron transfer efficiency. Enhanced current output was observed with the addition of more composite layers. The highest current, 23.7 ± 1.7 µA at 0.3 V, was obtained in electrodes with six composite layers containing 2 µg GOx, 3.6 µg PVI-Os-dme, and 2.2 µg Poly (ethylene glycol) diglycidyl ether. The apparent K _m ^app and maximum current (I _max ) were measured as 9.1 mM and 29.4 µA, respectively. The electrode maintained stable performance upon repeated application with only a slight decline in efficiency.