Nonlight-Driven Aggregation-Induced Emission Luminogens for Bioimaging and Theranostics

Aggregation-induced emission luminogens (AIEgens) have been prosperously developed and applied in the fields of optical imaging and theranostics since its establishment. Nowadays, AIEgens can fulfill nearly all requirements in optical imaging and theranostics with emission spectra ranging from visible to near-infrared wavelengths. Although a variety of AIEgens with varying wavelengths and functionalities have been continuously designed, their performance is heavily dependent on the use of conventional light sources, such as xenon lamps and lasers, which severely hinder further applications due to limited penetration depth and background autofluorescence in biological tissues. To mitigate these limitations and maximize the potential of AIEgens, unconventional excitation sources such as chemical energy, ultrasound, and X-ray offer effective alternatives that circumvent the drawbacks associated with traditional light-based constant excitation. In this Review, we introduce the fundamental principles governing the combination of unconventional excitation sources with AIEgens, highlight recent advancements in using AIEgens excited by these unconventional sources for bioimaging and theranostics, and discuss current challenges and future perspectives aimed at advancing the biomedical applications of AIEgens.