A biotinylated piperazine-rhodol derivative: a 'turn-on' probe for nitroreductase triggered hypoxia imaging.

We developed a nitroreductase responsive theranostic probe 1; it comprises biotinylated rhodol in conjunction with p-nitrobenzyl functionality. The probe 1 showed a remarkable fluorescence 'turn-on' signal in the presence of nitroreductase under physiological conditions. The probe is considerably stable within a wide biological pH range (6-8) and also is very sensitive toward a reducing micro-environment e.g. liver microsome. Further, it enables providing cellular and in vivo nematode images in a reducing microenvironment.