Hydrothermally Grown Porous Cobalt Oxide Nanostructures for Enzyme-Less Glucose Detection

Porous transition metal oxide nanostructures are very attractive electrode materials for electrochemical glucose sensing owing to their high surface area and excellent catalytic activity. Development of a low-cost electrode with high sensitivity and selectivity towards glucose sensing is attractive for non-invasive diabetes monitoring. In this work, porous CoO nanostructured electrodes were grown on fluorine doped tin oxide (FTO) coated glass substrates using hydrothermal synthesis for enzyme-less glucose sensing. CoO porous electrodes showed glucose sensitivity ~887.49 µAmM^-1cm^-2, within glucose concentration range ~ 5 µM–0.425 mM. Such porous electrodes demonstrated lower detection limit ~ 1.76 µM with fast response time. To demonstrate non-invasive glucose detection, salivary glucose sensing experiments were also carried out in this study and showed glucose sensitivity ~ 854.30 µAmM^-1cm^-2.