Regulator-carrying dual-responsive integrated AuNP composite fluorescence probe for in situ real time monitoring apoptosis progression

Apoptosis is a typical programmed death mode with complex molecular regulation mechanisms. Developing advanced strategies to monitor apoptosis progression is conducive to disease treatment related with apoptosis. Herein, we developed a regulator-carrying dual-responsive integrated AuNP composite fluorescence probe for in situ real time monitoring apoptosis progression. The nanoprobe is constructed by modifying specially designed double-stranded DNA (dsDNA) and caspase 3-specific cleavable peptides (pep) to the surface of AuNP. After uptake by cells, the nanoprobe recognizes miRNA 21 and triggers fluorescence recovery, enabling silencing and imaging of the upstream signaling molecule miRNA 21. Once miRNA 21 is silenced, the downstream signaling molecule caspase 3 is activated and cleaves the substrate peptides, and fluorescence is restored for in situ imaging of caspase 3. The apoptosis induced by silencing miRNA 21 has been successfully implemented in HeLa and A549 cells. The expression level of miRNA 21 and corresponding changes of caspase 3 have also been effectively monitored. These results suggested this nanoprobe will be a potential tool for apoptosis-related biomedical research and clinical application.