A novel Met-IR-782 near-infrared probe for fluorescent imaging-guided photothermal therapy in breast cancer.

In this work, a novel photothermal agent based on methionine (Met) was synthesized, which shows strong absorbance in the near infrared ray (NIR) region and is available for NIR imaging and in vivo photothermal therapy in a mouse model. Comparing to free IR-782, the obtained Met modified fluorescent dye (Met-IR-782) exhibited excellent fluorescence stability, preferable photothermal conversion efficiency under 780 nm laser irradiation and specific targeting to MCF7 (human breast adenocarcinoma cell line) cells. The fluorescence imaging ability enabled in situ monitoring of the tumor accumulation of Met-IR-782. The photothermal cytotoxicity assays in vitro and photothermal therapy treatments in vivo indicated that Met-IR-782 could efficiently target and suppress the growth of MCF7 xenograft tumors. Hence, Met-IR-782 is a potential fluorescent agent for NIR imaging-guided cancer photothermal therapy in clinical application. This work highlights the prospect of using light absorbing agents for NIR imaging-guided photothermal therapy.