Cargando…

The transition from single molecule to ensemble revealed by fluorescence polarization.

Fluorescence polarization measurements in the condensed phase provide rich information on rotational dynamics and interactions between macromolecules. An important parameter in these studies is the limiting polarization or p(o) which is the emission polarization in the absence of molecular rotation....

Descripción completa

Detalles Bibliográficos
Autores principales: Bell, Toby D. M., Clayton, Andrew H. A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4313089/
https://www.ncbi.nlm.nih.gov/pubmed/25640875
http://dx.doi.org/10.1038/srep08158
_version_ 1782355204332584960
author Bell, Toby D. M.
Clayton, Andrew H. A.
author_facet Bell, Toby D. M.
Clayton, Andrew H. A.
author_sort Bell, Toby D. M.
collection PubMed
description Fluorescence polarization measurements in the condensed phase provide rich information on rotational dynamics and interactions between macromolecules. An important parameter in these studies is the limiting polarization or p(o) which is the emission polarization in the absence of molecular rotation. Here we explore how molecular number averaging affects the observed value of p(o). Using a simple mathematical model we show that for a collection of fluorescent dipoles (1–50 molecules) the fluorescence polarization (p) increases with the number of molecules (N) due to the progressive onset of photo-selection with a relation of the form p = p(o)(1 − N(−β)). This concept is demonstrated experimentally using single molecule polarization measurements of perylene diimide dye molecules in a rigid polymer matrix where it is shown that the average emission polarization increases significantly when the number of molecules per averaging window is increased from 1 to 10 molecules. These results suggest that the definition of limiting polarization needs to be refined in the quasi-single molecule regime. Moreover, these results pave a new way for measuring clustering of molecules from single cluster polarization histograms.
format Online
Article
Text
id pubmed-4313089
institution National Center for Biotechnology Information
language English
publishDate 2015
publisher Nature Publishing Group
record_format MEDLINE/PubMed
spelling pubmed-43130892015-02-11 The transition from single molecule to ensemble revealed by fluorescence polarization. Bell, Toby D. M. Clayton, Andrew H. A. Sci Rep Article Fluorescence polarization measurements in the condensed phase provide rich information on rotational dynamics and interactions between macromolecules. An important parameter in these studies is the limiting polarization or p(o) which is the emission polarization in the absence of molecular rotation. Here we explore how molecular number averaging affects the observed value of p(o). Using a simple mathematical model we show that for a collection of fluorescent dipoles (1–50 molecules) the fluorescence polarization (p) increases with the number of molecules (N) due to the progressive onset of photo-selection with a relation of the form p = p(o)(1 − N(−β)). This concept is demonstrated experimentally using single molecule polarization measurements of perylene diimide dye molecules in a rigid polymer matrix where it is shown that the average emission polarization increases significantly when the number of molecules per averaging window is increased from 1 to 10 molecules. These results suggest that the definition of limiting polarization needs to be refined in the quasi-single molecule regime. Moreover, these results pave a new way for measuring clustering of molecules from single cluster polarization histograms. Nature Publishing Group 2015-02-02 /pmc/articles/PMC4313089/ /pubmed/25640875 http://dx.doi.org/10.1038/srep08158 Text en Copyright © 2015, Macmillan Publishers Limited. All rights reserved http://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder in order to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/4.0/
spellingShingle Article
Bell, Toby D. M.
Clayton, Andrew H. A.
The transition from single molecule to ensemble revealed by fluorescence polarization.
title The transition from single molecule to ensemble revealed by fluorescence polarization.
title_full The transition from single molecule to ensemble revealed by fluorescence polarization.
title_fullStr The transition from single molecule to ensemble revealed by fluorescence polarization.
title_full_unstemmed The transition from single molecule to ensemble revealed by fluorescence polarization.
title_short The transition from single molecule to ensemble revealed by fluorescence polarization.
title_sort transition from single molecule to ensemble revealed by fluorescence polarization.
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4313089/
https://www.ncbi.nlm.nih.gov/pubmed/25640875
http://dx.doi.org/10.1038/srep08158
work_keys_str_mv AT belltobydm thetransitionfromsinglemoleculetoensemblerevealedbyfluorescencepolarization
AT claytonandrewha thetransitionfromsinglemoleculetoensemblerevealedbyfluorescencepolarization
AT belltobydm transitionfromsinglemoleculetoensemblerevealedbyfluorescencepolarization
AT claytonandrewha transitionfromsinglemoleculetoensemblerevealedbyfluorescencepolarization