Development of fluorescent mitochondria probe based on 1,2-dihydropyrrolo[3,4-b]indolizine-3-one

Mitochondria are one of the most important organelles in our body. Recent studies showed morphology of polymorphous organelle mitochondria can be used as a relevant biological marker for certain diseases. In this study, we developed new fluorescent mitochondrial probe, 5, for monitoring mitochondrial morphology via rational probe design using 1,2-dihydropyrrolo[3,4-b]indolizine-3-one. To overcome the drawback of triphenylphosphonium incorporation, pyridinium group was introduced as a mitochondria targeting moiety. Additional incorporation of olefin moiety between pyridinium and indolizine core skeleton in 5 induced a bathochromic shift of both absorption and emission wavelength along with increased hydrophobicity. Finally, we found 5 selectively stains the mitochondria under the live-cell condition. This work indicated that a simple change of chemical structure in a certain organic fluorophore can cause a significant transition in staining pattern of bioprobes.