Mesoporous carbon nanospheres featured multifunctional fluorescent nanoprobe: Simultaneous activation and tracing of caspase-3 involved cell apoptosis

Caspase-3 is considered to be a key regulator of cell apoptosis. Simultaneous activation and detection of caspase-3 in living cells is therefore highly important for precise cancer therapy and therapeutic efficacy evaluation but it is still a key challenge. Herein, a novel and simple multifunctional peptide-tailored mesoporous carbon nanospheres (MCN) has been developed for simultaneous cancer photothermal therapy (PTT) and real-time imaging of caspase-3 induced cell apoptosis. The nanoprobe was facilely prepared by modifying fluorescein isothiocyanate (FITC)-tagged peptide specific to caspase-3 on the surface of MCN. The signal switch relies on the unique quenching effect of MCN on the fluorescently labeled peptide, cleavage of the peptide by activated caspase-3 will result in a significant fluorescence lighting-up for sensitive caspase-3 analysis. The detection limit of 0.4 pg·mL−1 with a linear range from 10 pg·mL−1 to 1 ng·mL−1 was achieved. Owing to the intrinsic properties of MCN, the nanoprobe not only can be served as photothermal transducer to activate caspase-3, but also can simultaneously real-time monitoring caspase-3 activity in living cells with high specificity. This work demonstrates a smart molecular imaging strategy for cell apoptosis, which also provides a potential new platform for apoptosis-related diagnosis and precise cancer therapeutic applications.