A turn-on fluorescent assay for glucose detection based on carbon dots/manganese dioxide assembly

In this work, a turn-on fluorescent assay based on carbon dots/manganese dioxide nanosheet (CDs/MnO 2 ) assembly was developed for the detection of glucose. The fluorescence of CDs was first quenched by the addition of MnO 2 nanosheet to form CDs/MnO 2 assembly, which leads to a fluorescence resonance energy transfer (FRET) process from CDs to MnO 2 nanosheet. When H 2 O 2 was introduced into the quenched CDs solution, the MnO 2 nanosheet was destroyed due to the redox reaction between H 2 O 2 and MnO 2 nanosheet, and the fluorescence of CDs was recovered accordingly. On this basis, by coupling with the oxidation reaction of glucose catalyzed by glucose oxidase, which produces gluconic acid and H 2 O 2 , a fluorescent assay for the quantitative analysis of glucose can be proposed. Under optimal conditions, the fluorescent intensity of CDs increased linearly with increasing concentrations of glucose from 2 to 200 μM, and the detection limit towards glucose was calculated to be 0.83 μM. In addition, the proposed fluorescent assay was successfully applied to the determination of glucose in serum samples with satisfactory results. This proposed fluorescent assay is simple, cost-effective and environmentally friendly, and thereby holding great potential for diabetes management and biosensing applications.