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Fluorescence polarization measures energy funneling in single light-harvesting antennas-LH2 vs conjugated polymers.

Camacho Dejay, Rafael LU ; Tubasum, Sumera LU ; Southall, June; Cogdell, Richard J; Sforazzini, Giuseppe; Anderson, Harry L; Pullerits, Tönu LU and Scheblykin, Ivan LU (2015) In Scientific Reports 5.
Abstract
Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ε). We studied individual peripheral antennas of purple bacteria (LH2) and single CP... (More)
Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ε). We studied individual peripheral antennas of purple bacteria (LH2) and single CP chains of 20 nm length. As expected from a perfect antenna, LH2s showed funneling efficiencies close to unity. In contrast, CPs showed lower average funneling efficiencies, greatly varying from molecule to molecule. Cyclodextrin insulation of the conjugated backbone improves EET, increasing the fraction of CPs possessing ε = 1. Comparison between LH2s and CPs shows the importance of the protection systems and the protein scaffold of LH2, which keep the chromophores in functional form and at such geometrical arrangement that ensures excellent EET. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Scientific Reports
volume
5
publisher
Nature Publishing Group
external identifiers
  • pmid:26478272
  • wos:000362986400001
  • scopus:84945218867
ISSN
2045-2322
DOI
10.1038/srep15080
language
English
LU publication?
yes
id
97a8a527-2f6f-425b-bcfc-433bfa6b7e58 (old id 8149009)
date added to LUP
2015-11-16 14:30:12
date last changed
2017-09-24 03:56:57
@article{97a8a527-2f6f-425b-bcfc-433bfa6b7e58,
  abstract     = {Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ε). We studied individual peripheral antennas of purple bacteria (LH2) and single CP chains of 20 nm length. As expected from a perfect antenna, LH2s showed funneling efficiencies close to unity. In contrast, CPs showed lower average funneling efficiencies, greatly varying from molecule to molecule. Cyclodextrin insulation of the conjugated backbone improves EET, increasing the fraction of CPs possessing ε = 1. Comparison between LH2s and CPs shows the importance of the protection systems and the protein scaffold of LH2, which keep the chromophores in functional form and at such geometrical arrangement that ensures excellent EET.},
  articleno    = {15080},
  author       = {Camacho Dejay, Rafael and Tubasum, Sumera and Southall, June and Cogdell, Richard J and Sforazzini, Giuseppe and Anderson, Harry L and Pullerits, Tönu and Scheblykin, Ivan},
  issn         = {2045-2322},
  language     = {eng},
  publisher    = {Nature Publishing Group},
  series       = {Scientific Reports},
  title        = {Fluorescence polarization measures energy funneling in single light-harvesting antennas-LH2 vs conjugated polymers.},
  url          = {http://dx.doi.org/10.1038/srep15080},
  volume       = {5},
  year         = {2015},
}