Flower-like CoO nanowire-decorated Ni foam: A non-invasive electrochemical biosensor for glucose detection in human saliva

•CoO nanowires self-assembled into flower-like structures grown on Ni foam.•The catalyst with numerous mesopores possesses high specific surface area.•The catalyst facilitates the glucose diffusion to accelerate reaction kinetics.•The catalyst shows ultrahigh sensitivity, low LOD, and long-term stability. Diabetes is a prevalent disease that necessitates invasive and uncomfortable methods for monitoring glucose levels, posing the risk of infection. Consequently, there is an urgent need for non-invasive glucose biosensors to aid in diabetes diagnosis and management. This study presents a novel non-invasive electrochemical biosensor capable of detecting glucose concentration in human saliva. The biosensor utilizes a nickel foam substrate adorned with needle-like CoO nanowires, which offer an ideal surface area for nanowire growth. These nanowires exhibit a self-assembled flower-like nanostructure with a highly porous configuration, presenting an exceptional BET surface area of 154.3 m2 g−1 and displaying excellent catalytic performance. The combination of the substrate, nanowires, and nanostructures results in remarkable sensitivity (28.22 mA mM−1 cm−2), a low detection limit (0.55 μM), a wide sensing range (0.005-2.525 mM), and satisfactory stability and reproductivity. Experimental results demonstrate a remarkable recovery rate (100.1 %) for glucose detection in real human saliva samples, highlighting the potential of this biosensor for real-time and non-invasive glucose monitoring. This work holds promising implications for the future management of diabetes and the healthcare system dedicated to diabetes patients. [Display omitted]