A multi-functional fluorescent probe with aggregation-induced emission characteristics: Mitochondrial imaging, photodynamic therapy and visualizing therapeutic process in zebrafish model

The combination of fluorescent (FL) probe and photosensitizer (PS) is a powerful tool for monitoring the changes of specific organelles while studying the photodynamic therapy (PDT) processes at the organelle level. It is very valued for biomedical application but remained challenging due to the lack of ideal FL PDT agent. In this work, an aggregation-induced emission (AIE)-active FL probe (AIE-FR-TPP) by conjugation of a far red/near-infrared (FR/NIR) emitting AIE fluorogen with the mitochondria-targeting group, is reported as a multi-functional fluorophore for mitochondrial imaging and PDT. As for bioimaging, AIE-FR-TPP can selectively light up the cellular mitochondria with low working concentration, short staining time and good biocompatibility. As for PDT, the probe can target mitochondria precisely and generate reactive oxygen species (ROS) efficiently both in living cells and zebrafish embryos. Moreover, AIE-FR-TPP is capable of monitoring the morphological changes of mitochondria based on the AIE effect. These results demonstrate that a real-time visual PDT process at the organelle level in living zebrafish embryos is achieved for the first time by using the AIE PS to induce mitochondrial ROS collapse and report the morphological change on site and in time.