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Proceedings Paper

Endoscopic sensing of pH in the distal lung (Conference Presentation)
Author(s): Debaditya Choudhury; Michael G. Tanner; Sarah McAughtrie; Fei Yu; Bethany Mills; Tushar R. Choudhary; Sohan Seth; Thomas Craven; James M. Stone; Ioulia K. Mati; Colin J. Campbell; Mark Bradley; Christopher K.I. Williams; Kevin Dhaliwal; Timothy A. Birks; Robert R. Thomson
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Paper Abstract

In healthy humans, the physiological state in the distal lung alveolar acinar units is tightly regulated by normal homeostatic mechanisms. Pulmonary abnormalities such as chronic obstructive pulmonary disease, that are characterized by recurrent cycles of inflammation and infection involving dense infiltration by myeloid derived peripheral blood cells, may result in significant perturbation of the homeostatic baselines of physiology in addition to host tissue damage. Therefore, the ability to quantify and monitor physiology (e.g. pH, glucose level, oxygen tension) within the alveolar acinar units would provide a key biomarker of distal lung innate defence. Although in vitro modeling of fundamental biological processes show remarkable sensitivity to physiological aberrations, little is known about the physiological state of the distal lung due to the inability to concurrently access the alveolar sacs and perform real-time sensing. Here we report on previously unobtainable measurements of alveolar pH using a fiber-optic optrode and surface enhanced Raman spectroscopy (SERS) and show that alveolar pH changes in response to ventilation. The endoscope-deployable optrode consisted of para-mercaptobenzoic acid functionalized 150 nm gold nanoshells located at the distal end, and an asymmetric dual-core optical fiber designed for spatially separated optical pump delivery and SERS signal collection in order to circumvent the unwanted Raman signal originating from the fiber itself. We demonstrate a ~ 100-fold increase in SERS signal-to-fiber background ratio and pH sensing at multiple sites in the respiratory acinar units of a whole ex vivo ovine lung model with a measurement accuracy of ± 0.07 pH units.

Paper Details

Date Published:
PDF: 1 pages
Proc. SPIE 10041, Optical Techniques in Pulmonary Medicine II, 100410B; doi: 10.1117/12.2251925
Show Author Affiliations
Debaditya Choudhury, Heriot-Watt Univ. (United Kingdom)
Univ. of Edinburgh (United Kingdom)
Michael G. Tanner, Heriot-Watt Univ. (United Kingdom)
Queen's Medical Research Institute, The Univ. of Edinburgh (United Kingdom)
Sarah McAughtrie, Queen's Medical Research Institute, The Univ. of Edinburgh (United Kingdom)
School of Chemistry, The Univ. of Edinburgh (United Kingdom)
Fei Yu, Univ. of Bath (United Kingdom)
Bethany Mills, Queen's Medical Research Institute, The Univ. of Edinburgh (United Kingdom)
Tushar R. Choudhary, IB3, Heriot-Watt Univ (United Kingdom)
Queen's Medical Research Institute, The Univ. of Edinburgh (United Kingdom)
Sohan Seth, School of Informatics, The Univ. of Edinburgh (United Kingdom)
Thomas Craven, Queen's Medical Research Institute, The Univ. of Edinburgh (United Kingdom)
James M. Stone, Univ. of Bath (United Kingdom)
Ioulia K. Mati, School of Chemistry, University of Edinburgh (United Kingdom)
Colin J. Campbell, School of Chemistry, The Univ. of Edinburgh (United Kingdom)
Mark Bradley, Queen's Medical Research Institute, The Univ. of Edinburgh (United Kingdom)
School of Chemistry, The Univ. of Edinburgh (United Kingdom)
Christopher K.I. Williams, School of Informatics, The Univ. of Edinburgh (United Kingdom)
Kevin Dhaliwal, Queen's Medical Research Institute, The Univ. of Edinburgh (United Kingdom)
Timothy A. Birks, Univ. of Bath (United Kingdom)
Robert R. Thomson, Heriot-Watt Univ. (United Kingdom)
Queen's Medical Research Institute, The Univ. of Edinburgh (United Kingdom)


Published in SPIE Proceedings Vol. 10041:
Optical Techniques in Pulmonary Medicine II
Melissa J. Suter; Stephen Lam; Matthew Brenner, Editor(s)

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Endoscopic-sensing-of-pH-in-the-distal-lung-Conference-Presentation



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