Photo-isomerization of the Cyanine Dye Alexa-Fluor 647 (AF-647) in the Context of dSTORM Super-Resolution Microscopy.
Chemistry
; 25(65): 14983-14998, 2019 Nov 22.
Article
em En
| MEDLINE
| ID: mdl-31515919
ABSTRACT
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 metastable, 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 photobleaching of AF-647 occurs with very low quantum yield and is partially suppressed by the anaerobic redox buffer.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Chemistry
Assunto da revista:
QUIMICA
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Reino Unido