Abstract

Background and Methods: Dual-emission fluorescent nanosensor for the detection of glucose has been developed by simply mixing the blue-emission C-dots (CDs) with red-emission glutathione modified CdTe QDs.

Results and Discussion: The ratiometric fluorescence system exhibits dual emission peaks at 442 nm and 600 nm under a single excitation wavelength (365 nm). Due to the strong quenching effect of hydrogen peroxide to the quantum dots, the fluorescence of the QDs in the nanocomposite system could be selectively quenched by H2O2, while the fluorescence of the CDs remained constant, resulting in a distinguishable fluorescence color evolution (from red to blue) of the nanosensor which could be visible through naked eye. When this nanosensor was mixed with glucose oxidase, H2O2 can be produced by the enzyme catalysis reaction, which could quench the fluorescent intensity of QDs. So this system can be used to detect glucose. The limit of detection of this present method was as low as 0.1 μM.

Conclusion: The result for glucose was satisfying, suggesting its potential application for glucose sensing.

Keywords: Ratiometric fluorescence, carbon dots, quantum dots, glucose, diabetes, nanosensor.

Graphical Abstract