A rapid responsive colorimetric and near-infrared fluorescent turn-on probe for imaging exogenous and endogenous peroxynitrite in living cells

Abstract

Rapid, specific and sensitive near-infrared (NIR) fluorescent probes for endogenous peroxynitrite (ONOO−) are valuable tools for the research of ONOO− in living systems. In this paper, we developed a new colorimetric and NIR fluorescent turn-on probe for ONOO− by using a NIR fluorescent chromenylium-cyanine hybrid as the fluorophore and a hydrazide as the reactive site. This probe exhibits prominent features during detecting ONOO− including rapid response (<2 s), high selectivity and sensitivity, long excitation wavelength (640 nm), distinct colorimetric (colorless to blue) and significant NIR fluorescent turn-on signal changes as well as low cytotoxicity. The fluorescence enhancement at 698 nm is more than 100-fold and the detection limit is as low as 25 nM for ONOO−. We also showed that this probe could be used for bioimaging of both exogenous and endogenous peroxynitrite in living cells, indicating it can be used as a powerful tool for the biological research of peroxynitrite in living systems.