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

Abstract

In this work, a turn-on fluorescent assay based on carbon dots/manganese dioxide nanosheet (CDs/MnO2) assembly was developed for the detection of glucose. The fluorescence of CDs was first quenched by the addition of MnO2 nanosheet to form CDs/MnO2 assembly, which leads to a fluorescence resonance energy transfer (FRET) process from CDs to MnO2 nanosheet. When H2O2 was introduced into the quenched CDs solution, the MnO2 nanosheet was destroyed due to the redox reaction between H2O2 and MnO2 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 H2O2, 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.