Towards clinical application of exhaled volatile organic compound biomarkers: optimising breath sampling methods.

Sampling breath volatile organic compounds (VOCs) has the potential for real time detection and monitoring of a wide range of diseases. Over 1000 VOCs have been detected in breath to date and provide a potential non-invasive source of biomarkers and information about the underlying metabolic state of the body.

Whilst increasingly large scale studies have been conducted in the last ten years, a clinically relevant breath VOC test has yet to be widely implemented. One reason for this is the number of confounding factors that must be accounted for during breath collection which makes reproducing published results difficult. Recent work on breath holding, oral versus nasal breathing (Sukul et al. 2014, 2017) and time of day (Wilkinson et al. 2019) has highlighted the need for standardised sampling protocols. Fractional exhaled nitric oxide levels, which are routinely used for asthma diagnosis, are highly affected by these physiological parameters and it is therefore likely that the level of breath VOCs is similarly impacted. These differences are of particular concern in respiratory diseases where the underlying lung physiology for an individual may change dramatically over time. Further, whilst there has been interest in the variability of breath samples collected over a short time frame (Phillips et al. 2014) further work is needed to investigate changes across hours, days and seasonsin orsder to facilitate longer term clinical studies.

This project will build on sampling expertise within the group to assess the impact of clinically relevant changes in lung physiology on exhaled VOCs and investigate the short and long term variation observed in an individual’s breath profile. These results will contribute to the optimisation of an existing lung function model that uniquely incorporates realistic rendering of ventilation heterogeneity and gas washout in order to determine the factors governing exhaled VOC concentrations in health and disease.

Candidates are expected to hold (or be about to obtain) a minimum upper second class honours degree (or equivalent) in a related area / subject. Candidates with experience in analytical methods, especially gas chromatography-mass spectrometry, alongside and interest and aptitude in multivariate data analysis, are encouraged to apply.

For information on how to apply for this project, please visit the Faculty of Biology, Medicine and Health Doctoral Academy website (https://www.bmh.manchester.ac.uk/study/research/apply/). Informal enquiries may be made directly to the primary supervisor.

For international students we also offer a unique 4 year PhD programme that gives you the opportunity to undertake an accredited Teaching Certificate whilst carrying out an independent research project across a range of biological, medical and health sciences. For more information please visit www.internationalphd.manchester.ac.uk