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 emissions peak at 442nm 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 observed obviously by the naked eye. When this nanosensor 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.