Supraparticle Nanoarchitectonicswith Bright GoldNanoclusters Induced by Host–Guest Recognition for VolatileAmine and Meat Freshness Detection

The aggregation-induced emission enhancement (AIEE) of metal nanoclusters brought about many exciting applications for metal nanoclusters in food safety monitoring. However, it is still challenging to controllably synthesize monodispersed metal nanocluster supraparticles with AIEE properties for food safety monitoring. In this work, we synthesized bright gold nanoclusters (AuNCs) supraparticles (CB[<i>n</i>]/AuNCs) through supramolecular host–guest recognition between cucurbit[<i>n</i>]uril (CB[<i>n</i>] <i>n</i> = 7 and 8) and surface ligands of ATT-AuNCs. The ATT-AuNCs emission was enhanced by 15-fold, and the quantum yield of the synthesized CB[7]/AuNCs reached 52%. The CB[7]/AuNCs can sensitively and reversibly respond to environmental pH variation based on the protonation reaction of ATT ligands. Based on this, we realized a sensitive fluorescence turn-on sensing for ammonia with a limit of detection of as low as 0.2 ppm. Notably, a fluorescence turn-on paper sensor was constructed and successfully applied in meat freshness monitoring through the signal “turn-on” mode. This method provided an easy, controllable, and highly biocompatible strategy for the synthesis of AIEE-based metal nanoclusters, which laid the foundation for improving the performance of metal nanoclusters and expanding their applications.