Light-Up Probe for Targeted and Activatable Photodynamic Therapy with Real-Time In Situ Reporting of Sensitizer Activation and Therapeutic Responses

Integrated systems that offer traceable cancer therapy are highly desirable for personalized medicine. Herein, a probe is reported that is composed of a red-emissive photosensitizer (PS) with aggregation-induced emission characteristics and a built-in apoptosis sensor with activatable green emission for targeted cancer cell ablation and real-time monitoring of PS activation and therapeutic response. The probe is nonemissive in aqueous media and can be selectively uptaken by αvβ3 integrin overexpressed cancer cells. Cleavage of the probe by intracellular glutathione leads to release of the apoptosis sensor and red fluorescence turn-on to report the PS activation. Upon light irradiation, the PS can generate reactive oxygen species to induce cell apoptosis and activate caspase-3/-7, which will cleave the apoptosis sensor to yield intense green fluorescence. Both the red and green emission can be obtained through a single wavelength excitation, which makes the probe very convenient for therapeutic protocol development.