Isoindigo-Based Dual-Acceptor Conjugated Polymers Incorporated Conjugation Length and Intramolecular Charge Transfer for High-Efficient Photothermal Conversion.

Photothermal tumor therapy (PTT) and photoacoustic imaging (PA) have emerged as promising noninvasive diagnostic and therapeutic approaches for cancer treatment. However, the development of efficient PTT agents with high photostability and strong near-infrared (NIR) absorption remains challenging. In this study, we synthesized three isoindigo-based dual-acceptor conjugated polymers (P-IIG-TPD, P-IIG-DPP, and P-IIG-EDOT-BT) via a green and non-toxic direct arylation polymerization method and characterized their optical, electrochemical, and NIR photothermal conversion properties. By incorporating two acceptors into the backbone, the resulting polymers exhibited enhanced photothermal conversion efficiency due to improved synergy among conjugation length, planarity, and intramolecular charge transfer. The nanoparticles of P-IIG-EDOT-BT and P-IIG-DPP had a uniform size distribution around 140 nm and exhibited remarkable NIR absorption at 808 nm. In addition, P-IIG-EDOT-BT and P-IIG-DPP nanoparticles exhibited high photothermal conversion efficiencies of 62% and 78%, respectively. This study promotes the molecular design of conjugated polymers as NIR photothermal conversion materials and provides guidance for the development of novel dual-acceptor conjugated polymers for tumor diagnosis and treatment. This article is protected by copyright. All rights reserved.