Development of pH‐Responsive BODIPY Probes for Staining Late Endosome in Live Cells

Abstract Reported is a new fluorescent probe based on boron–dipyrromethene dye (BODIPY) for late endosome staining in live cells. Among the 14 pH‐responsive BODIPY‐based far‐red/near‐infrared dyes used, it was found that a (4‐methyl‐1‐piperazinyl)phenyl‐substituted BODIPY could stain late endosomes in three different cell lines. This BODIPY dye was applicable for measurement of the fusion time of late endosomes and lysosomes, thereby demonstrating the utility of this dye for functional analyses of late endosomes in live cells.