Multiple rotor-based photothermal agents for NIR-I/NIR-II fluorescence imaging-guided tumor phototherapy†

Photothermal therapy (PTT) is emerging as a promising alternative therapy for tumor ablation through spatiotemporally controlled hyperthermia. However, designing near-infrared photothermal agents with a high photothermal conversion efficiency (PCE) and high photostability remains considerably challenging. To address this limitation, we engineered optimal molecule 3TPA by employing CF₃-BODIPY as an electron-deficient core and incorporating three electron-donating triphenylamine rotors, which showed an extended absorption wavelength and improved PCE. To optimize the therapeutic performance, 3TPA was further encapsulated into a DSPE-mPEG_5k-based amphiphilic polymer to form 3TPA NPs, which exhibited high PCE (η = 57.2%) and remarkable photostability. In vivo studies revealed that 3TPA NPs selectively accumulated in tumor sites under NIR-I/NIR-II fluorescence imaging guidance, simultaneously enabling effective photo-mediated tumor ablation through a precision PTT effect. This work not only presents a robust NIR-II therapeutic agent but also opens up more possibilities for its application in photothermal therapy in the field of biomedicine.