The Midas Touch by Internal Stimuli: Activatable Luminogens with Near‐Infrared Aggregation‐Induced Emission for Potent Bioimaging and Theranostics

Abstract As a modality of optical imaging, fluorescence imaging of biochemical analytes holds significant potential in the field of disease diagnosis and therapy. However, the non‐responsive fluorophores are not able to selectively and sensitively detect lesions, resulting in a poor signal‐to‐background ratio and compromised accuracy. The utilization of activatable sensors, in contrast, is capable of effectively overcoming these limitations by displaying variations in fluorescence intensity and spectral wavelength in response to physiological parameters. Aggregation‐induced emission luminogens (AIEgens), particularly those emitting fluorescence in the near‐infrared (NIR, 700–1700 nm) window, have practical application prospects in disease theranostics due to their excellent photostability, deeper penetration depth, and enhanced fluorescence intensity in physiological environments. In this review, an overview of the advancements in research on NIR AIEgens for internal stimuli‐activated diagnosis and treatment of diseases is provided. The design principles of responsive NIR AIEgens and their biomedical applications are exemplified with representative examples, categorized based on the type of stimuli. Finally, the review concludes with a brief discussion of the challenges, opportunities, and future prospects of activatable NIR AIEgens in the field of disease photo theranostics.