J-aggregate fluorescence probe constructed based on AIE units for analysis of Zn2+, Cu2+ ions in food and biological systems

The precise detection of metal ions is crucial in food safety, biomedical diagnostics, and environmental monitoring. Although traditional “on-off” fluorescence probes are frequently utilized, their anti-interference capability remains a limitation. This study synthesized three new copper-based fluorescent probes: PTA, PTP, and PTD. Among them, PTD exhibited unique aggregation-induced emission (AIE) properties. PTD's remarkable selectivity for Zn 2+ was due to the formation of Zn 2+ -induced J-aggregates, which resulted in a concentration-dependent fluorescence redshift from green to yellow and then to red. Additionally, PTD demonstrated a rapid and sensitive response to Cu 2+ , and it was successfully integrated into a smartphone-based platform for the semi-quantitative detection of Zn 2+ and Cu 2+ in real food samples. The effectiveness in biological applications was also validated through live-cell imaging tests. This work contributes to the creation of highly selective and interference-resistant ratiometric fluorescence sensors by leveraging the special process of target metal ion-induced J-aggregate production in AIE-based probes.