Ratiometric fluorescence detection of cysteine and homocysteine with a BODIPY dye by mimicking the native chemical ligation.

The selective detection of cysteine and homocysteine over glutathione and other amino acids was demonstrated with an 8-MeS-BODIPY probe by mimicking the native chemical ligation approach, which allowed the selective and ratiometric fluorescence sensing of cysteine over other biothiols at physiologically relevant concentrations and in different organs of a zebrafish.