Small molecular organic optical agents with synergistic effects of photothermal therapy (PTT) and photodynamic therapy (PDT), hold credible promise for anti-tumor therapy by overcoming individual drawbacks and enhancing photon utilization efficiency. However, developing effective dual-function PTT-PDT photosensitizers (PSs) for efficient synergistic phototherapy remains challenging. Here, a benz[c,d]indolium-substituted hemicyanine named Rh-BI, which possesses a high photothermal conversion efficiency of 41.67% by exhaustively suppressing fluorescence emission, is presented. Meanwhile, the rotating phenyl group at meso-site induces charge recombination to enhance the molar extinction coefficient up to 13.58 × 104 M-1cm-1, thereby potentiating the photodynamic effect. Under 808 nm irradiation, Rh-BI exhibits significant phototoxicity in several cancer cell types in vitro with IC50 values as low as ≈0.5 µM. Moreover, treatment of 4T1 tumor-bearing mice with Rh-BI under laser irradiation successfully inhibits tumor growth. In a word, an effective strategy is developed to build PTT-PDT dual-functional optical materials based on hemicyanine backbone for tumor therapy by modulating conjugation system interaction to adjust the energy consumption pathway.
Keywords: Dual‐function; NIR‐absorbing; PTT‐PDT material; Photosensitizer; Photostability.
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