Zinc-doped carbon dots for hypochlorite ultrasensitive determination: from aqueous monitoring to live-cells imaging.

To overcome the limitations of conventional detection methods for Hypochlorite (ClO⁻), bright blue-emitting zinc-doped carbon dots (Zn-CDs) were constructed via a streamlined and rapid hydrothermal method (within 2 h). The Zn-CDs possessed excellent water dispersibility and physicochemical stability with a quantum yield (QY) of 10.05%. Based on the Zn-O coordination structure could provide specific binding sites for ClO⁻, the Zn-CDs as fluorescent probes enabled ultrasensitive and selective detection of ClO⁻ in range of 0.1-50 µM with an exceptionally low limit of detection (LOD) of 8.14 nM. Mechanistic investigations revealed that the fluorescence quenching was attributed to surface oxidation and subsequent electron transfer. Furthermore, the Zn-CDs demonstrated excellent biocompatibility with negligible cytotoxicity and were successfully employed for intracellular fluorescence imaging of both exogenous and endogenous ClO⁻. These finding established the developed Zn-CDs as a powerful and practical analytical platform for environmental water quality monitoring and precision biomedical diagnostics.