Fig. 3
a Electron paramagnetic resonance (EPR) spectra to detect 1O2 generation. b Fluorescence spectra of 1O2 probes with various concentrations of PTZ-TQ-AIE dots from 0 to 30 μg/mL were recorded (solid line: with laser, dotted line: without laser). c Fluorescence intensities of 1O2 probes with PTZ-TQ-AIE dots under irradiation for different time durations (808-nm NIR laser, 0.25 W/cm2). d Intracellular ROS production by DCFH-DA in HepG2 cells (50 μg/mL; 808 nm, 0.25 W/cm2, 10 min; scale bar: 200 μm). e Fluorescence images of HepG2 cells co-stained by Calcein-AM (green fluorescence for live cells) and PI (red fluorescence for dead cells) (50 μg/mL; 808 nm, 0.25 W/cm2, 10 min; scale bar: 200 μm). f In vitro cytotoxicity of PTZ-TQ-AIE dots against LO2 cells, HepG2 cells with and without 808-nm NIR laser (0.25 W/cm2) after 24-h incubation