Probing Cancer Cells through Intracellular Aggregation-Induced Emission Kinetic Rate of Copper Nanoclusters

pH-responsive luminescent copper nanoclusters (Cu NCs) with aggregation-induced emission (AIE) characteristics have been synthesized. Upon internalization into living cells, the NCs displayed a cellular pH environment-dependent luminescence change with orange-red emission at pH_i 4.5, whereas bright green emission was observed over time at pH_i 7.4, through their AIE attributes. Furthermore, the intracellular AIE kinetics of the NC probe was measured in MCF-7 cells and compared to that of HEK-293 cells. Intriguingly, the intracellular rate constant value derived for AIE kinetics in MCF-7 cells was found to be 3-fold higher than that in HEK-293 cell lines, whereas the value was 2-fold higher than that observed in aqueous medium. This provided a new platform to study different cell lines based on intracellular AIE in living cells, with additional potential for future applications in cellular imaging, diagnostics, and disease detection