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