Unveiling cellular mysteries: Advances in BODIPY dyes for subcellular imaging

Fluorescence imaging has become crucial in cell biology, mainly because of its ability to visualize the cells at the molecular level. Subcellular organs including mitochondria, lysosomes, the endoplasmic reticulum, and the Golgi apparatus play a pivotal role in the physiological and pathological processes in living cells. Among the great number of fluorescent trackers developed so far is 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY), which has the following features: high quantum yields, sharp excitation and emission maxima, high stability, and feasibility to tune chemical, physical, and biological properties. Lately, there has been great progress towards enhancing BODIPY dyes that are water-soluble, cell membrane-permeable, and precisely targeted. Herein, this review article will introduce the BODIPY probes for subcellular imaging with application to various regions of living cells or tissues. Furthermore, we describe the process of functionalizing BODIPY probes to enhance their selectivity and preferential localization in organelles. Moreover, the targeting mechanism is explained to give insights into how different cellular microenvironments dictate the nature of moieties to be attached to the BODIPY scaffold. In addition, confocal microscopy and colocalization studies are reported to verify the desired subcellular distribution of the probes. Importantly, in vitro and in vivo studies are reported to ascertain the safety of the probes for clinical uses. We hope this review will stimulate interest among researchers and students and expedite the development of BODIPY chemistry in biomedical applications.