Fluorescent probes for ferroptosis bioimaging: advances, challenges, and prospects

Ferroptosis is a form of regulatory cell death distinct from caspase-dependent apoptosis and plays an important role in life entities. Since ferroptosis involves a variety of complex regulatory factors, the levels of certain biological species and microenvironments would change during this process. Thus, the investigation of the level fluctuation of key target analytes during ferroptosis is of great significance for disease treatment and drug design. Toward this aim, multiple organic fluorescent probes with simple preparation and non-destructive detection have been developed, and research over the past decade has uncovered a vast array of homeostasis and other physiological characteristics of ferroptosis. However, this significant and cutting-edge topic has not yet been reviewed. In this work, we aim to highlight the latest breakthrough results of fluorescent probes for monitoring various bio-related molecules and microenvironments during ferroptosis at the cellular, tissue and in vivo levels. Accordingly, this tutorial review has been organized according to the target molecules identified by the probes including ionic species, reactive sulfur species, reactive oxygen species, biomacromolecules, microenvironment, and others. In addition to providing new insights into the findings of each fluorescent probe in ferroptosis studies, we also discuss the defects and limitations of the probes developed, and highlight the potential challenges and further prospects in this domain. We anticipate that this review will convey profound implications for designing powerful fluorescent probes to decrypt changes in key molecules and microenvironments during ferroptosis.