Boosting the AIEgen-based photo-theranostic platform by balancing radiative decay and non-radiative decay

Abstract

It is noted that developing a single-molecule-triggered photo-theranostic platform for precise diagnosis and efficient cancer therapy is of great significance, but it still remains a difficult issue. In particular, it is challenging to balance the radiative decay (fluorescence) and non-radiative decay (photothermal effects) pathways for developed theranostic systems. Hence, the donor–acceptor–donor (D–A–D)-type aggregation-induced emission luminogen (AIEgen) of DTPA-BBTD is designed in this study. This molecule exhibits excellent absorption in the first near infrared (NIR-I) window as well as high brightness in the second near infrared (NIR-II) region, together with the favorable photoluminescence quantum yield (PLQY) of 1.51% compared with the commercial NIR-II fluorescent dye IR 26 used as a reference. In addition, owing to its efficient twisted intramolecular charge transfer effects and loose molecular packing when aggregated, DTPA-BBTD also exhibits an efficient photothermal conversion capability, thus providing the single-molecule-triggered photo-theranostic platform. It is observed that DTPA-BBTD-based AIE dots are successfully applied for NIR-II fluorescence imaging and NIR-I photoacoustic imaging to visualize the vasculature of mice and observe tumors in vivo, respectively. Moreover, photothermal therapy by using the developed AIE dots under irradiation is finally applied to well hinder tumor growth. This result demonstrates that manipulating the molecular backbone in AIEgens to balance the radiative decay and non-radiative decay can be an efficient strategy for constructing high-performance photo-theranostic platforms for precise cancer diagnosis and therapy.