Lookup NU author(s): Emeritus Professor Anthony Harriman,
Dr Joshua Karlsson,
Dr Alex Laude,
Dr Michael Hall
This is the authors' accepted manuscript of an article that has been published in its final definitive form by Wiley-VCH Verlag , 2019.
For re-use rights please refer to the publisher's terms and conditions.
Cyanine dyes, as used in super‐resolution fluorescence microscopy, undergo light‐induced “blinking”, enabling localization of fluorophores with spatial resolution beyond the optical diffraction limit. Despite a plethora of studies, the molecular origins of this blinking are not well understood. Here, we examine the photophysical properties of a bio‐conjugate cyanine dye (AF‐647), used extensively in dSTORM imaging. In the absence of a potent sacrificial reductant, light‐induced electron transfer and intermediates formed via the meta‐stable, triplet‐excited state are considered unlikely to play a significant role in the blinking events. Instead, it is found that, under conditions appropriate to dSTORM microscopy, AF‐647 undergoes reversible photo‐induced isomerization to at least two long‐lived dark species. These photo‐isomers are characterized spectroscopically and their interconversion probed by computational means. The first‐formed isomer is light sensitive and transforms to a longer‐lived species in modest yield that could be involved in dSTORM related blinking. Permanent photo‐bleaching of AF‐647 occurs with very low quantum yield and is partially suppressed by the anaerobic redox buffer.
Author(s): Harriman A, Karlsson JKG, Laude A, Hall MJ
Publication type: Article
Publication status: Published
Journal: Chemistry - A European Journal
Print publication date: 22/11/2019
Online publication date: 13/09/2019
Acceptance date: 11/09/2019
Date deposited: 14/09/2019
ISSN (print): 0947-6539
ISSN (electronic): 1521-3765
Publisher: Wiley-VCH Verlag
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