A Highly Efficient Chemiluminescence Probe for the Detection of Singlet Oxygen in Living Cells

Singlet oxygen is among the reactive oxygen species (ROS) with the shortest life-times in aqueous media because of its extremely high reactivity. Therefore, designing sensors for detection of O-1(2) is perhaps one of the most challenging tasks in the field of molecular probes. Herein, we report a highly selective and sensitive chemiluminescence probe (SOCL-CPP) for the detection of O-1(2) in living cells. The probe reacts with O-1(2) to form a dioxetane that spontaneously decomposes under physiological conditions through a chemiexcitation pathway to emit green light with extraordinary intensity. SOCL-CPP demonstrated promising ability to detect and image intracellular O-1(2) produced by a photosensitizer in HeLa cells during photodynamic therapy (PDT) mode of action. Our findings make SOCL-CPP the most effective known chemiluminescence probe for the detection of O-1(2). We anticipate that our chemiluminescence probe for O-1(2) imaging would be useful in PDT-related applications and for monitoring O-1(2) endogenously generated by cells in response to different stimuli.