Triplet Tellurophene-Based Semiconducting Polymer Nanoparticles for Near-Infrared-Mediated Cancer Theranostics

Semiconducting polymer (SP) nanoparticles (NPs) have recently emerged as one of the most promising agents for photoacoustic imaging (PAI)-guided photothermal/photodynamic therapy (PTT/PDT). Herein, a triplet tellurophene-based SP (PNDI-2T) was synthesized with efficient tin-free direct heteroarylation polycondensation. The PNDI-2T NPs display remarkable near-infrared absorption and low cytotoxicity. In addition, PNDI-2T NPs can generate abundant reactive oxygen species (ROS) since tellurophene facilitates the intersystem crossing to generate triplet excited states. Remarkably, PNDI-2T NPs present a high photothermal conversion efficiency (eta = 45%) and a high ROS yield (Phi Delta = 38.7%) under 808 nm laser irradiation. Furthermore, we showed that PNDI-2T NPs could be excellent PAI-guided PTT/PDT agents for cancer theranostics. This study provides a new route to developing highly efficient and low cytotoxic agents for PAI-guided PTT/PDT.