Engineering a Near-Infrared D-A-A-D BODIPY Dimer for ROS Generation and Photothermal Conversion in Multimodal Synergistic Phototherapy

To address the limitations of traditional single-mode phototherapy, this study developed a novel, symmetrical D-A-A-D structured BODIPY dimer (<b>P-P</b>) via a facile "one-pot" oxidative homocoupling reaction, with triphenylamine as the electron donor (D), BODIPY as the electron acceptor (A), and butadiyne as the conjugated bridge. Compared to its D-A monomer counterpart (<b>P</b>), <b>P-P</b> displayed a red-shifted absorption spectrum (465-725 nm), enhanced charge separation, an extended triplet excited-state lifetime (165 μs vs 104 μs), and significantly improved type I, type II, and total reactive oxygen species (ROS) generation, along with superior photothermal conversion efficiency. These properties enable <b>P-P</b> to achieve multimodal phototherapy with enhanced therapeutic efficacy. As a result, <b>P-P</b> demonstrated efficient cellular uptake, high phototoxicity (with an IC₅₀ of 15.2 μM), and minimal dark toxicity in tumor cells. This work offers a promising strategy for developing high-performance phototherapeutic agents, paving the way for advancing multimodal synergistic phototherapy in clinical applications.