Encapsulating gold nanoclusters into zinc-glutamate metal organic frameworks for ferric ions detection in zebrafish embryos

Gold nanoclusters (AuNCs), ultrasmall aggregates of gold atoms with unique molecular-like electronic structures and excellent photoluminescent properties, have emerged as promising candidates for fluorescence-based bioanalytical applications. However, the fluorescence intensity of AuNCs is relatively low, which significantly restricts their practical applications in high sensitivity fluorescence detection and imaging. This study successfully designed a fluorescent probe by encapsulating AuNCs in zinc-glutamate metal organic frameworks (ZG-MOF). Notably, the fluorescence intensity of the encapsulated AuNCs was significantly enhanced by nearly one-third owing to the confined pore size of ZG-MOF. This probe exhibits high specificity for ferric ions recognition with a rapid response. Furthermore, it shows an excellent linear correlation with ferric ions concentrations in the range 5.0–1000.0 µM. Moreover, the probe has been successfully applied to real-time fluorescence imaging of ferric ions in zebrafish embryos, and can monitor ferroptosis in zebrafish embryos induced by exogenous agents, achieving in vivo visualization of ferric ions distribution.