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

Sensors

Fei Yu¹  KerrianneHarringtonHarrington¹  HarryA. C. Wood¹  Kev Dhaliwal²  Mark Bradley²  TusharR. Choudhary²  Alicia Megia-Fernandez³  Muhammed Ucuncu³  Katjana Ehrlich⁴  Debaditya Choudhury⁴  MichaelG. Tanner⁴ 

[1] Centre for Photonics and Photonic Materials, University of Bath, Claverton Down, Bath BA27AY, UK;EPSRC Proteus IRC Hub, Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK;School of Chemistry, EaStChem, University of Edinburgh, Joseph Black Building, West Mains Road, Edinburgh EH9 3FF, UK;Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK;

关键词: fluorescence spectroscopy;    time-resolved spectroscopy;    optical fibre sensing;    biological sensor;   

DOI  :  10.3390/s20216115

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown