Alkyl Side-chain Engineering Enables Significant Suppression of Conformational Relaxation for Improved Near Infrared-Ⅱ Imaging-guided Uterine Recanalization Surgery and Cancer Phototheranostics

Phototheranostics have recently aroused extreme attention due to its exceptional advantages. Developing a single agent synchronously sharing powerful absorption, high second near-infrared (NIR-II) fluorescence efficiency and photothermal conversion efficiency is urgently demand but extremely scarce. Herein, two kinds of NIR-II phototheranositc agents featuring aggregation-induced emission, NIR-II fluorescence imaging (FLI) and photothermal therapy (PTT) are constructed through constructing electron donor-acceptor (D-A) molecular skeleton with side-chain engineering. Profiting from sufficient molecular rotors, highly twisted configurations, large reorganization energy and high HRf values concentrating stretching/scissoring of alkyl chain, BBT2 is endowed with NIR-II fluorescence property and high photothermal conversion. The nanoparticles (NPs) fabricated with BBT2 exhibit significant NIR-II FLI-guided uterine cavity recanalization surgery and efficient PTT therapy under laser irradiation both in vitro and orthotopic 4T1 mice models. Transvaginal BBT2 NPs are highly effective in assessing uterine cavity patency in mice and the subsequent pregnancy rate with 6 months of follow-up after uterine cavity recanalization surgery is synchronously evaluated.