Glucose oxidase assisted visual detection of glucose using oxygen deficient α-MoO3-x nanoflakes.

An optical method is described for the quantitation of glucose by using oxygen-deficient α-MoO3-x nanoflakes. It is based on the use of glucose oxidase (GOx) which produces hydrogen peroxide on oxidation of glucose. Hydrogen peroxide then oxidizes the α-MoO3-x nanoflakes, and this results in a visible color change from blue to colorless. The color change can be measured photometrically at 740 nm. The method has a 68 nM detection limit. Graphical Abstract Mechanism of glucose detection using blue colored oxygen deficient 2D α-MoO3-x nanoflakes. Hydrogen peroxide (H2O2) is formed as a by-product in the conversion of glucose to glucono-1,5-lactone by glucose oxidase (GOx). In the presence of H2O2, the oxygen vacancies in α-MoO3-x nanoflakes are filled up, and this leads to the loss of blue color of the nanoflakes because they are converted back to colorless bulk α-MoO3.