Abstract
The photothermal therapy(PTT)has come across as a promising noninvasive therapeutic strategy for tu-mor 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 sec-ond 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.
基金项目
国家自然科学基金(61875131)
Shen-zhen Key Laboratory of Photonics and Biophotonics(ZDSYS20210623092006020)