Intermolecular hydrogen-bonding as a robust tool toward significantly improving the photothermal conversion efficiency of a NIR-II squaraine dye

作     者：Songtao Cai Liuying Wu Yuan Li Soham Samanta Jinying Wang Bing Liu Feihu Wu Kaitao Lai Yingchao Liu Junle Qu Zhigang Yang Songtao Cai;Liuying Wu;Yuan Li;Soham Samanta;Jinying Wang;Bing Liu;Feihu Wu;Kaitao Lai;Yingchao Liu;Junle Qu;Zhigang Yang

作者机构：Center for Biomedical Photonics&Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China 

出 版 物：《Chinese Chemical Letters》 (中国化学快报（英文版）)

年 卷 期：2024年第35卷第4期

页      面：310-315页

核心收录：

学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 07[理学] 070304[理学-物理化学(含∶化学物理)] 0703[理学-化学] 

基　　金：financially supported by the National Natural Science Foundation of China (No.61875131) Shenzhen Key Laboratory of Photonics and Biophotonics (No.ZDSYS20210623092006020)。 

主　　题：Squaraine-based cyanine Hydrogen bonds High PCE Anti-aggregation Photothermal therapy 

摘      要：The photothermal therapy(PTT) has come across as a promising noninvasive therapeutic strategy for tumor treatment. However, low photothermal conversion efficiency(PCE) and hydrophobicity may impede the therapeutic efficacy of organic photothermal agents and an efficient PTT-agent must overcome these two major challenges. In this work, we developed a new strategy to promote higher PCE wherein the intermolecular hydrogen-bonding interaction between the single dye molecule and water facilitated the transformation of the absorbed energy into the heat. A hydrophilic squaraine dye(SCy1) with the second near-infrared region(NIR-II) absorption and extremely low emission were designed to exhibit much higher PCE than that of the analogues of pentamethine-dyes(PCy1, PCy2). The presence of the ‘–O- at middle of squaric cycle enabled the intermolecular H-bonding formation between the SCy1 and water to promote the energy dissipation channel. Moreover, the introduction of long-chain phenylsulfonate groups helped in to improve the water solubility apart from serving as an additional means of further enhancing PCE through fluorescence quenching. Therefore, SCy1 with a squaraine backbone and long-chain sulfonate moieties revealed outstanding photothermal stability and anti-aggregation activity apart from showing exceptionally high PCE(74%) in water. SCy1 demonstrated excellent therapeutic efficacy when applied in the PTT treatment of tumor-bearing mice under a laser irradiation of 915 nm.