Conjugated D–A Polymers to Integrate the Through‐Bond and Through‐Space Charge Transfers to Boost the One‐For‐All Phototheranostics

A conjugated D–A polymer of PY2V-BDTF is designed to combine the through-bond/through-space charge transfer features in a single molecule. PY2V-BDTF displays efficient absorption and emission in NIR region. Also, ROS generation in both type I and type II pathways as well as excellent photothermal properties can be obtained in their corresponding nanoparticles, finally resulting efficient one-for-all phototheranostics.

Abstract

To achieve the efficient cancer therapy, one-for-all phototheranostics are highly important, but their engineering of agents is still challenging. Particularly, the balancing of emission and reactive oxygen species (ROS) generation is urgently needed in NIR-II region. To address this issue, a conjugated D–A polymer of PY2V-BDTF is designed to combine the through-bond/through-space charge transfer (TBCT/TSCT) features in a single molecule by connecting D and A units with the rotatable vinyl linkers. It is observed that the TBCT feature red-shifts the emission wavelength into NIR-II region with peak at 1015 nm (PLQY = 2.51%) in PY2V-BDTF NPs. On the other hand, the TSCT feature lowers the energy gap of singlet and triplet excited-states to obtain efficient ROS generation in photodynamic therapy (PDT) process (Type I and Type II). In addition, high photothermal conversion efficiency (PCE) of 61.5% are also obtained in PY2V-BDTF NPs, which is also one of the highest values for organic agents in one-for-all phototheranostics. Finally, imaging-guided cancer therapy for both in vitro and in vivo are finally obtained to well achieve the tumor elimination. This work demonstrates that integrating the TBCT and TSCT into one system may be the efficient method to achieve agents for one-for-all phototheranostics in cancer therapy.