Synthesis of luminescent CePO₄:Tb/Au composite for glucose detection

The glucose oxidase (GOx) is commonly used as targeting molecule for glucose detection since a specific enzymatic reaction can occur, namely, catalytic oxidation of glucose by GOx. However, the intrinsic denaturation of natural enzyme is a problem in the use that leads to the detection inaccuracy and unstability. Here, we designed and prepared the luminescent CePO₄:Tb/Au composite for glucose sensing, in which small-sized Au nanoparticles possess GOx-mimicking activity for catalytic oxidation of glucose and the in situ generated H₂O₂ quenches the luminescence of CePO₄:Tb, enabling the fluorescent detection of glucose. The quenching of luminescence in dilute solutions can be well described by the Stern-Volmer relationship in a wide analyte concentration range with the Ksv quenching constant of 13070 M⁻¹. A detection limit of 5.25 μM and a good sensing selectivity were achieved. More importantly, the problem of unstability using natural enzyme in the glucose determination can be efficiently solved by using Au as catalyst instead of GOx due to long-term preserved catalytic activity of Au. Therefore, our developed fluorescent system for glucose detection is potential in the biochemical analysis.