NIR‐II AIE Liposomes for Boosting Type‐I Photodynamic and Mild‐Temperature Photothermal Therapy in Breast Cancer Treatment

Phototheranositcs has recently aroused extreme attention due to its exceptional advantages. However, the poor photothernostic efficiency, limited penetration depth, strong oxygen-dependence, and inevitable damage to normal tissue of conventional photothernostic materials severely hindered their total theranostic efficacy. Herein, a series of near-infrared second (NIR-II) photosensitizers (PSs) featuring aggregation-induced emission (AIE), NIR-II fluorescence imaging (FLI), type I photodynamic therapy (PDT) and mild-temperature photothermal therapy (PTT) are constructed through dual-strategy methods combining donor group engineering and fluorination engineering. Profiting from sufficient molecular rotors and high electronegativity of fluorine, the developed 2-(2-((5-(4-((4-(diphenylamino)phenyl)(phenyl)amino)phenyl)thiophen-2-yl)methylene)-5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (BTS-2F) and 2-(2-((5-(4-(bis(4-(diphenylamino)phenyl)amino)phenyl)thiophen-2-yl)methylene)-5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (TTS-2F) are endowed with NIR-II AIE property, high radical reactive oxygen species (ROS) generation ability and mild-temperature photothermal conversion. Through thin film hydration method, the prepared BTS-2F and TTS-2F loaded liposomes exhibit significant NIR-II FLI and improved type-I PDT/mild-temperature PTT therapy under laser irradiation both in vitro and orthotopic 4T1 mice models.