Soft-templated fabrication of multifunctional selenium nanozymes using carbon quantum dots for sensing applications

In this study, carbon quantum dots (CQDs) served as functional templates to successfully construct novel CQD-stabilized selenium nanozymes (CQDs-SeNPs) with dual fluorescence and enzyme-like activity response characteristics. The stabilization and functionalization effects of CQDs not only achieved highly dispersed SeNPs (with D_H of 33.76 ± 7.72 nm and Zeta potential of −45.67 mV), but also endowed it with excellent photoluminescence properties and Hg²⁺-triggered oxidase-like activity. A multimodal Hg²⁺ sensing platform was developed by synergistically combining fluorescence quenching and enzyme activity activation. The sensor demonstrates high selectivity, rapid response (<20 min), and dual-mode detection: fluorescence (0.78–12.50 μmol/L, LOD = 0.14 μmol/L) and colorimetric (25.00–50.00 μmol/L, LOD = 6.13 μmol/L), achieving a broad detection range of 0.78–50.00 μmol/L. The results of this study fully underscore the role of CQDs in enhancing nanomaterial performance and highlight the potential of selenium-based nanozymes for rapid Hg²⁺ detection.