Carbon Nanodots as Dual-Mode Nanosensors for Selective Detection of Hydrogen Peroxide

Hydrogen peroxide (H₂O₂) is an important product of oxidase-based enzymatic reactions, such as glucose/glucose oxidase (GOD) reaction. Therefore, the probing of generated H₂O₂ for achieving the detection of various carbohydrates and their oxidases is very significative. Herein, we report one kind of dual-emission carbon nanodots (CDs) that can serve as novel dual-mode nanosensors with both fluorometric and colorimetric output for the selective detection of H₂O₂. The dual-model nanosensors are established only by the undecorated dual-emission CDs, where significant fluorometric and colorimetric changes are observed with the addition of different concentrations of H₂O₂ in the CD solution, which benefit to the achievement of the naked-eye detection for H₂O₂. The mechanism of the nanosensors can be attributed to the fact that the external chemical stimuli like hydroxyl radicals from H₂O₂ bring about the change of surface properties and the aggregation of CDs, which dominate the emission and absorption of CDs. The constructed dual-mode nanosensors exhibit good biocompatibility and high selectivity toward H₂O₂ with a linear detection range spanning from 0.05 to 0.5 M and allow the detection of H₂O₂ as low as 14 mM.