A Si‐CdTe Composite Quantum Dots Probe with Dual‐Wavelength Emission for Sensitively Monitoring Intracellular H2O2

Abstract Hydrogen peroxide is an important reactive oxygen species (ROS) that acts as a significant marker of oxidative stress in certain diseases. Owing to the autofluorescence of biological samples, H 2 O 2 monitoring remains challenging. Here, Si‐CdTe quantum dots (QDs) are prepared as novel ratiometric fluorescent probes prepared for sensitive detection of H 2 O 2 and glucose, the low detection limit of H 2 O 2 and glucose is 79 and 140 n m , respectively. In this article, CdTe QDs are combined with Si QDs to reduce the cytotoxicity of CdTe. The survival rate of HeLa cells remains at 80% after incubation with the Si‐CdTe QDs at a concentration of 500 µg mL −1 for 24 h. Fluorescence extinguishes based on 488 and 514 nm channels are used as internal references to avoid environmental interference and demonstrate selective H 2 O 2 biosensing. In addition, the probe has an excellent colocalization effect in the lysosome under the 514 nm channel, with a maximum Pearson coefficient of 0.96. The advantages of easy preparation, low toxicity, high resistance to photobleaching, and high specificity of the Si‐CdTe QDs probes provide a new and convenient means to monitor and detect changes in the endogenous intracellular H 2 O 2 concentration and to select 514 nm lysosomal colocalization dyes.