Bright Aggregation-Induced Emission Nanoparticles for Two-Photon Imaging and Localized Compound Therapy of Cancers

Photodynamic therapy (PDT) is a non-invasive therapeutic strategy for cancer treatment but it always suffers from low reactive oxygen species (ROS) efficiency generated from traditional organic dyes owing to weak absorption in the optical transparent window of biological tissues and fluorescence quenching at a concentrated solution or in nanoparticles. Herein, we present cationic lipid-encapsulated aggregation-induced emission (AIE) nanoparticles (NPs) that have a high quantum yield (23%) and a maximum two-photon absorption (TPA) cross-section of 560 GM irradiated by near infrared light (800 nm). The AIE NPs can serve as imaging agents for spatiotemporal imaging of tumor tissues with a penetration depth up to 505 µm on mice melanoma model. Noteworthy, the AIE NPs can efficiently generate singlet oxygen ( 1 O 2 ) and highly toxic hydroxyl radicals ( · OH) upon 800 nm-light irradiation for photodynamic tumor ablation. In addition, the AIE NPs can be effectively cleared from the mouse body after the imaging and therapy. This study provides a new strategy to develop theranostic agent for cancer image-guided PDT with high brightness, superior photostability and high biosafety