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Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors

Numerous optodes, with fluorophores as the chemical sensing element and optical fibres for light delivery and collection, have been fabricated for minimally invasive endoscopic measurements of key physiological parameters such as pH. These flexible miniaturised optodes have typically attempted to ma...

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Autores principales: Ehrlich, Katjana, Choudhary, Tushar R., Ucuncu, Muhammed, Megia-Fernandez, Alicia, Harrington, Kerrianne, Wood, Harry A. C., Yu, Fei, Choudhury, Debaditya, Dhaliwal, Kev, Bradley, Mark, Tanner, Michael G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7663438/
https://www.ncbi.nlm.nih.gov/pubmed/33121191
http://dx.doi.org/10.3390/s20216115
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author Ehrlich, Katjana
Choudhary, Tushar R.
Ucuncu, Muhammed
Megia-Fernandez, Alicia
Harrington, Kerrianne
Wood, Harry A. C.
Yu, Fei
Choudhury, Debaditya
Dhaliwal, Kev
Bradley, Mark
Tanner, Michael G.
author_facet Ehrlich, Katjana
Choudhary, Tushar R.
Ucuncu, Muhammed
Megia-Fernandez, Alicia
Harrington, Kerrianne
Wood, Harry A. C.
Yu, Fei
Choudhury, Debaditya
Dhaliwal, Kev
Bradley, Mark
Tanner, Michael G.
author_sort Ehrlich, Katjana
collection PubMed
description Numerous optodes, with fluorophores as the chemical sensing element and optical fibres for light delivery and collection, have been fabricated for minimally invasive endoscopic measurements of key physiological parameters such as pH. These flexible miniaturised optodes have typically attempted to maximize signal-to-noise through the application of high concentrations of fluorophores. We show that high-density attachment of carboxyfluorescein onto silica microspheres, the sensing elements, results in fluorescence energy transfer, manifesting as reduced fluorescence intensity and lifetime in addition to spectral changes. We demonstrate that the change in fluorescence intensity of carboxyfluorescein with pH in this “high-density” regime is opposite to that normally observed, with complex variations in fluorescent lifetime across the emission spectra of coupled fluorophores. Improved understanding of such highly loaded sensor beads is important because it leads to large increases in photostability and will aid the development of compact fibre probes, suitable for clinical applications. The time-resolved spectral measurement techniques presented here can be further applied to similar studies of other optodes.
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spelling pubmed-76634382020-11-14 Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors Ehrlich, Katjana Choudhary, Tushar R. Ucuncu, Muhammed Megia-Fernandez, Alicia Harrington, Kerrianne Wood, Harry A. C. Yu, Fei Choudhury, Debaditya Dhaliwal, Kev Bradley, Mark Tanner, Michael G. Sensors (Basel) Article Numerous optodes, with fluorophores as the chemical sensing element and optical fibres for light delivery and collection, have been fabricated for minimally invasive endoscopic measurements of key physiological parameters such as pH. These flexible miniaturised optodes have typically attempted to maximize signal-to-noise through the application of high concentrations of fluorophores. We show that high-density attachment of carboxyfluorescein onto silica microspheres, the sensing elements, results in fluorescence energy transfer, manifesting as reduced fluorescence intensity and lifetime in addition to spectral changes. We demonstrate that the change in fluorescence intensity of carboxyfluorescein with pH in this “high-density” regime is opposite to that normally observed, with complex variations in fluorescent lifetime across the emission spectra of coupled fluorophores. Improved understanding of such highly loaded sensor beads is important because it leads to large increases in photostability and will aid the development of compact fibre probes, suitable for clinical applications. The time-resolved spectral measurement techniques presented here can be further applied to similar studies of other optodes. MDPI 2020-10-27 /pmc/articles/PMC7663438/ /pubmed/33121191 http://dx.doi.org/10.3390/s20216115 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Ehrlich, Katjana
Choudhary, Tushar R.
Ucuncu, Muhammed
Megia-Fernandez, Alicia
Harrington, Kerrianne
Wood, Harry A. C.
Yu, Fei
Choudhury, Debaditya
Dhaliwal, Kev
Bradley, Mark
Tanner, Michael G.
Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors
title Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors
title_full Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors
title_fullStr Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors
title_full_unstemmed Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors
title_short Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors
title_sort time-resolved spectroscopy of fluorescence quenching in optical fibre-based ph sensors
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7663438/
https://www.ncbi.nlm.nih.gov/pubmed/33121191
http://dx.doi.org/10.3390/s20216115
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