Biomarker-activatable probes based on smart AIEgens for fluorescence and optoacoustic imaging

Fluorophores with aggregation-induced emission (AIE) are characterized by many advantageous features for biomedical applications, including excellent photostability and enhanced fluorescent emission in aqueous milieu with minimal aggregation caused quenching (ACQ) effect. The abnormal levels of biomarkers are closely correlated with various diseases. Hence developing new strategies for detection and imaging of disease biomarkers fluorescently and optoacoustically is of high significance for early diagnosis of diseases. Probes (contrast agents) play essential roles in fluorescent and optoacoustic imaging. They have been extensively explored and applied in recent years, which induce the emergence of a variety of new probes in particular the biomarker-activatable probes based on smart AIEgens for fluorescence and optoacoustic imaging. In this review, we aim to summarize the latest development and progress as well as biomedical applications of the biomarker-activatable probes based on smart AIEgens. We focus on their design strategies and highlight the prospects and challenges in fluorescent and optoacoustic imaging.