Unifying Mechanism for Thiol-Induced Photoswitching and Photostability of Cyanine Dyes
| Autor: | Yasser Gidi, Liam Payne, Megan S. Michie, Viktorija Glembockyte, Martin J. Schnermann, Gonzalo Cosa |
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| Rok vydání: | 2020 |
| Předmět: |
Molecular Structure
General Chemistry Carbocyanines Photochemical Processes 010402 general chemistry Photochemistry Single-molecule experiment 01 natural sciences Biochemistry Fluorescence Article Catalysis Photoinduced electron transfer 0104 chemical sciences Adduct Electron transfer chemistry.chemical_compound Colloid and Surface Chemistry Intersystem crossing chemistry Excited state Sulfhydryl Compounds Cyanine Density Functional Theory Fluorescent Dyes |
| Zdroj: | J Am Chem Soc |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | Cyanines (Cy3, Cy5, Cy3B) are the most utilized dyes for single-molecule fluorescence and localization-based super-resolution imaging. These modalities exploit cyanines’ versatile photochemical behavior with thiols. A mechanism reconciling seemingly divergent results and enabling control over cyanine photoreactivity is however missing. Utilizing single-molecule fluorescence on Cy5 and Cy5B, transient-absorption spectroscopy, and DFT modeling on a range of cyanine dyes, herein we show that photoinduced electron transfer (PeT) from a thiolate to Cy in their triplet excited state and then triplet-to-singlet intersystem crossing in the nascent geminate radical pair are crucial steps. Next, a bifurcation occurs, yielding either back electron transfer and regeneration of ground state Cy, required for photostabilization, or Cy-thiol adduct formation, necessary for super-resolution microscopy. Cy regeneration via photoinduced thiol elimination is favored by adduct absorption spectra broadening. Elimination is also shown to occur through an acid-catalyzed reaction. Overall, our work provides a roadmap for designing fluorophores, photoswitching agents, and triplet excited state quenchers for single-molecule and super-resolution imaging. |
| Databáze: | OpenAIRE |
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