Sensors, Vol. 20, Pages 6115: Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors

Sensors, Vol. 20, Pages 6115: Time-Resolved Spectroscopy of Fluorescence Quenching in Optical Fibre-Based pH Sensors Sensors doi: 10.3390/s20216115 Authors: Katjana Ehrlich Tushar R. Choudhary Muhammed Ucuncu Alicia Megia-Fernandez Kerrianne Harrington Harry A. C. Wood Fei Yu Debaditya Choudhury Kev Dhaliwal Mark Bradley Michael G. Tanner 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 ...
Source: Sensors - Category: Biotechnology Authors: Tags: Article Source Type: research