Utilization of Nonradiative Excited-State Dissipation for Promoted Phototheranostics Based on an AIE-Active Type I ROS Generator
Yifei Wang, Yudong Sun, Jiabing Ran, Huiran Yang, Shuzhang Xiao, Jing Yang, Changying Yang, Huimin Wang, Yi Liu
Abstract
As for effective multimodal phototheranostic AIEgens, it is important to find strategies for manipulating photophysical dissipation to achieve optimized performance. Herein, a “all-in-one” phototheranostic AIEgen, (E)-3-(2-(2-(5-(4-(diphenylamino)phenyl)thiophen-2-yl)vinyl)naphtho[1,2-d]thiazol-1-ium-1-yl)propane-1-sulfonate (NS-STPA) was constructed by a rigid coplanar grafting flexible rotor. NS-STPA nanoparticles (NPs) exhibited NIR fluorescent luminescence (FL) with φFL 2.78%. Upon 660 nm irradiation, the high photothermal conversion efficiency (39.01%) and effective reactive oxygen species (ROS) generation (5.28 times to Ce6) indicated the nonradiative decays are valuable in phototherapy. High •OH outputs showed NS-STPA NPs were outstanding type I ROS generators. The twisted D–A structure induced a large spin–orbit coupling (SOC), and insertion of thiophene decreased the S1–T1 energy gap (ΔEST). The nanoaggregate prolonged the triplet-state lifetime (τT). These all facilitate the intersystem crossing (ISC) for NS-STPA NPs. The photoinduced electron transfer resulted in •O2– and then •OH generation. In vivo evaluation indicated the promising application of NS-STPA NPs in FL and photothermal dual imaging-guided synergistic photodynamic and photothermal therapies.