We highlight the representative cases of fluorescent HOCl probes with mitochondria and lysosome-targetable ability. The discussion includes their design strategies, sensing mechanisms, and applications in bio-imaging of HOCl in organelles.

A cancer cell targeted fluorescent viscosity probe has been designed and synthesized to specifically visualise viscosity changes in biotin receptor (BiR) positive cells over biotin negative cells via dual-mode fluorescence imaging: fluorescence intensity mode and fluorescence lifetime mode.

Through rational design, two new mitochondria-targeted fluorescent viscosity probes were developed, which exhibited favorable properties such as large turn on fluorescence signal, good selectivity, low cytotoxicity, and high colocation coefficient (>0.90).