A fluorescent turn on nanoprobe for simultaneous visualization of dual-targets involved in cell apoptosis and drug screening in living cells.

Herein, a novel dual-responsive two-color fluorescent nanoprobe has been designed for the fluorescence activation imaging of cell apoptosis in living cells. The nanoprobe consists of a gold nanoparticle core functionalized with a dense layer of DNA aptamers and peptides, which shows high affinity and specific response to cytochrome c (Cyt c) and caspase-3, respectively. The formation of the aptamer-Cyt c complex and the cleavage of the specific peptide by caspase-3 can liberate the dye labelled aptamers and peptides from the surface of gold nanoparticles, and then recover their fluorescence. The turn-on and specific recognition properties of our nanoprobe allow for the sensitive and selective detection of Cyt c concentration and caspase-3 activity both in solutions and in living cells. The here proposed nanoprobe with the abilities of real-time monitoring the cell apoptosis and evaluating the apoptosis-related drug efficacy might serve as a potential interesting tool for studying the molecular mechanisms of apoptosis regulation or screening the apoptosis-based drugs.