2,6-Pyridinedicarboxylic Acid Covalently Bound Polydopamine for Enhanced Tumor Photothermal Therapy in NIR-I and NIR-II

作者：Xingxing Gao, Jingjing Li, Xiaoxu Li, Xing Yin, Shunze Cao, Ximing Pu, Juan Wang, Xiaoming Liao, Zhongbing Huang, Guangfu Yin · 发表于：ACS Applied Materials & Interfaces · 年份：2025 · DOI：10.1021/acsami.5c05572 · 被引用次数：6 · 研究领域：Nanoplatforms for cancer theranostics、Advanced Nanomaterials in Catalysis、Luminescence and Fluorescent Materials

Polydopamine (PDA) possesses potential as a photothermal agent for tumor treatment owing to its photothermal capacity, chemical modifiability, excellent biocompatibility, and selective biodegradability. However, weak near-infrared (NIR) light absorption seriously hinders its actual utilization, especially in NIR-II. This study presents a novel molecularly modified PDA with remarkably increased NIR absorption and remarkably enhanced photothermal conversion capacity in both NIR-I and NIR-II. Dopamine monomers are covalently bound with elaborately selected 2,6-pyridinedicarboxylic acid (DPA) through an amidation reaction and then undergo an oxidative polymerization to form DPA-doped PDA nanoparticles (DPA-PDA NPs). By constructing donor–acceptor pairs and extending the conjugation length of molecular units, the energy band gap of DPA-PDA between the highest occupied molecular orbital and the lowest unoccupied molecular orbital is diminished from 0.77 to 0.45 eV, facilitating the electron low-energy transition. Meanwhile, the content of carbon-centered free radicals is obviously raised via suppressing their dimerization and quenching by the conjugation effect and steric hindrance effect, where the strengthened electron spin and vibration may promote charge and energy transfers, increasing and accelerating the excited electron nonradiative decay. As a result, the DPA-PDA NPs exhibit the enhanced NIR light absorption (196 and 205% over PDA) and much higher photothermal conversion e...