Development of a prototype optical fibre CO2 skin gas sensor
A recent review highlighted the importance of carbon dioxide in predicting early tissue damage and concluded that future research is needed to find technological solutions to measure PCO2 in affected tissue continuously and non-invasively.
The Optics and Photonics Group at the University of Nottingham has developed optical fibre sensors for a number of applications, particularly in monitoring skin and in critical care, and for a range of parameters including gases. To achieve a sensitive and specific sensor response, the optical fibre is coated with a film whose refractive index or colour changes in the presence of an analyte of interest. As optical fibres are lightweight, flexible and compact they offer the potential to address the challenge of continuously and non-invasive monitoring of skin CO2.
For example, we have demonstrated different approaches including using metal organic frameworks as the coating of a long period grating (LPG) for sensing methanol and the application of mesoporous films to detect ammonia.
In this study we aim to demonstrate proof of concept measurements of CO2 emitted by the skin using an optical fibre sensor. Tasks involve
- Coat an optical fibre with a dye compound sensitive to CO2 (e.g. tetrasodium pyrophosphate, TSPP)
- Optimise the configuration of the optical fibre sensor by changing the concentration of the dye compound and through the use of long period grating
- Characterise the sensor response by comparison with a commercial CO2 sensor at different CO2 levels in a sealed chamber linked to gas cylinders (already available at Nottingham).
- Demonstrate preliminary measurements on skin on healthy volunteers, by placing hand inside a bag containing the optical fibre sensor and commercial CO2 sensor.
The main deliverable will be a test report including test data and information about the measurement performance of the sensor.