Luminescent sensing of Hg²⁺ ions using MOF-808 combined with Au25@BSA nanoclusters

• MOF-808/Au 25 @BSA is a selective and sensitive luminescent sensor for Hg²⁺ ions. • Sensor achieves a 4.6 nM detection limit, below WHO and USEPA water safety thresholds. • Hg²⁺ detection relies on d 10 -d 10 metallophilic interactions with Au₂₅@BSA clusters. • Robust luminescence is maintained across pH 6–9 and in complex aqueous environments. • MOF-808 enhances Au 25 @BSA stability, enabling long-term room-temperature sensing. The detection of Hg²⁺ ions in aqueous environments is crucial due to their environmental toxicity and potential health risks. In this study, we present a novel luminescent sensor based on Metal-Organic Framework MOF-808 functionalized with Au 25 @BSA gold nanoclusters (AuNCs) for the highly sensitive detection of trace Hg²⁺ ions. MOF-808, known for its robust structure and versatile chemical environment, provides an ideal platform for incorporating gold nanoclusters that exhibit unique optical properties. The integration of Au 25 @BSA in MOF-808 framework enhances the temporal and thermal stability of the gold nanoclusters while preserving their photoluminescence properties. The MOF-808/Au 25 @BSA composite behaves as a sensor relying on the quenching effect of Hg²⁺ on the luminescence of the gold nanoclusters embedded within the MOF matrix, offering a highly selective and sensitive detection method at concentrations as low as nM levels. Comprehensive characterizations of the MOF-808/Au 25 @BSA composite were conducted. This sensor demonstrates remarkable performance with high sensitivity, selectivity, and stability, making it a promising tool for environmental monitoring and analysis. This work highlights the potential of MOF-based luminescent sensors combined with gold nanoclusters in advancing the field of sensing applications.