All in one: Dual-mode probe for multivariate sensing heavy metal ions and cascade detecting biomarkers

The toxicity of heavy metals not only poses a threat to environment, but also causes oxidative stress in human body by disruption of redox biomarkers. It is crucial for detecting heavy metals and their associated biomarkers efficiently, but is still a great challenge. Herein, aggregation-induced emission (AIE) featured dual-ligand gold nanoclusters (NG-AuNCs) were fabricated and further treated as dual-mode multivariate probe for heavy metals and biomarkers. The NG-AuNCs achieved simultaneous detection silver (Ag⁺) and mercury (Hg²⁺) via fluorometric mode based on AIE enhancement and fluorescence quenching, with detection limits of 0.87 nM and 47.0 nM, respectively. And the cascade colorimetric sensing of biomarkers hydrogen peroxide (H₂O₂) and glutathione (GSH) with limits of 2.9 μM and 0.22 μM was accomplished based on the peroxidase (POD)-mimicking properties of NG-AuNCs. This dual-mode sensing system connects environmental monitoring with biological assessment, addressing the "exposure-effect" chain from heavy metal pollution to oxidative stress. The impressive sensing performance was verified by the recovery in real water and human serum, demonstrating excellent environmental tolerance. This work provides a novel strategy for designing multivariate probe serving as environmental surveillance and health risk assessment.