Pro-fluorescent mitochondria-targeted real-time responsive redox probes synthesised from carboxy isoindoline nitroxides: Sensitive probes of mitochondrial redox status in cells

Kok Leong Chong, Benjamin A. Chalmers, Jason K. Cullen, Amandeep Kaur, Jacek L. Kolanowski, Benjamin J. Morrow, Kathryn E. Fairfull-Smith, Martin J. Lavin, Nigel L. Barnett, Elizabeth J. New, Michael P. Murphy, Steven E. Bottle*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

6 Citations (Scopus)

Abstract

Here we describe new fluorescent probes based on fluorescein and rhodamine that provide reversible, real-time insight into cellular redox status. The new probes incorporate bio-imaging relevant fluorophores derived from fluorescein and rhodamine linked with stable nitroxide radicals such that they cannot be cleaved, either spontaneously or enzymatically by cellular processes. Overall fluorescence emission is determined by reversible reduction and oxidation, hence the steady state emission intensity reflects the balance between redox potentials of critical redox couples within the cell. The permanent positive charge on the rhodamine-based probes leads to their rapid localisation within mitochondria in cells. Reduction and oxidation also leads to marked changes in the fluorophore lifetime, enabling monitoring by fluorescence lifetime imaging microscopy. Finally, we demonstrate that administration of a methyl ester version of the rhodamine-based probe can be used at concentrations as low as 5 nM to generate a readily detected response to redox stress within cells as analysed by flow cytometry.

Original languageEnglish
Pages (from-to)97-110
Number of pages14
JournalFree Radical Biology and Medicine
Volume128
Early online date19 Mar 2018
DOIs
Publication statusPublished - 20 Nov 2018
Externally publishedYes

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