Self-Assembly of Gold Nanoclusters into a Metal-Organic Framework with Efficient Electrochemiluminescence and Their Application for Sensitive Detection of Rutin.

Ligand-protected gold nanoclusters (Au NCs) are promising electrochemiluminescence (ECL) emitters because of their striking optical properties and excellent biocompatibility, but free vibration and rotation of their ligand result in low ECL efficiency, dramatically limiting their applications. Herein, using the ligand of Au NCs as one of the building units, a Au NC-based metal-organic framework (Au NC-based MOF) was constructed by the coordination-assisted self-assembly strategy, which not only impedes the ligand rotation-induced energy dissipation but also diminishes the self-quenching effect due to the spatial distribution of Au NCs. As a proof of concept, the prepared GSH-Au NCs@ZIF-8 gives rise to a 10-fold enhanced anodic ECL efficiency compared to that of densely aggregated GSH-Au NCs with triethylamine as the coreactant. Based on high ECL efficiency of GSH-Au NCs@ZIF-8, a "signal off" sensing platform was proposed with rutin as a model analyte, achieving a low detection limit of 10 nM. Therefore, the strategy paves an effective and alternative methodology to enhance ECL efficiency of metal NCs, considerably broadening their potential applications in sensing analysis, clinical diagnosis, and light-emitting devices.