Enlarging Reservoir: High Absorption Coefficient Dyes Enable Synergetic Near Infrared-II Fluorescence Imaging and Near Infrared-I Photothermal Therapy

Yuanyuan Li, Jianquan Zhang, Shunjie Liu, Chen Zhang, Clarence Chuah, Youhong Tang, Ryan T.K. Kwok, Jacky W.Y. Lam, Hanlin Ou, Dan Ding, Ben Zhong Tang

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Although organic materials with near infrared (NIR)-II fluorescence and a photothermal effect have been widely investigated for the accurate diagnosis and treatment of tumors, optimizing the output signals of both remain challenging. Here, a strategy by “enlarging absorption reservoir” to address this issue, since an increase in photon absorption can naturally enhance output signals, is proposed. As a proof-of-concept, a large π-conjugated diketopyrrolopyrrole (DPP) unit is selected to fabricate strong light-absorbing systems. To enhance solid-state fluorescence, highly twisted alkylthiophene–benzobisthiadiazole–alkylthiophene and triphenylamine rotor are introduced to restrict the strong intermolecular π–π interactions. Moreover, the number of DPP units in molecules is engineered to optimize photophysical properties. Results show that TDADT with two DPP units possesses an exceptionally high molar absorptivity of 2.1 × 105 L mol−1 cm−1 at 808 nm, an acceptable NIR-II quantum yield of 0.1% (emission peak at 1270 nm), and a sizeable photothermal conversion efficiency of 60.4%. The excellent photophysical properties of the TDADT nanoparticles are particularly suitable for in vivo NIR-II imaging-guided cancer surgery and NIR-I photothermal therapy. The presented strategy provides a new approach of designing highly efficient NIR-II phototheranostic agents.

    Original languageEnglish
    Article number2102213
    Number of pages10
    JournalAdvanced Functional Materials
    Early online date7 May 2021
    DOIs
    Publication statusE-pub ahead of print - 7 May 2021

    Keywords

    • aggregation-induced emission
    • imaging-guided surgeries
    • near infrared-II imaging
    • phototheranostics
    • photothermal therapies

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