Gas Phase Aldehydes Detection in Exhaled Breath in Screening of Barrett's Esophagus

Abstract

Aldehydes, e.g., acetaldehyde, have been classified as toxic and carcinogenic volatile organic compounds (VOCs) and are recognized as one determinant of upper aerodigestive tract cancer like Barrett's esophagus. Measuring aldehyde levels in breath provides information about the aldehydes released by abnormal cells, the level of aldehyde dehydrogenase (ALDH2) activity, and risks and diseases associated with high levels of acetaldehyde, which include liver disease and lung and upper digestive cancers. Devices currently available for breath analysis are state-of-the-art, high-resolution mass spectrometry instruments. These instruments have some drawbacks such as size, initial cost, and operational expense. Electrochemical sensors are capable of miniaturization and are available as portable and handheld breathalyzers. The non-invasive nature of breath analysis and its easy sampling makes smaller devices a more attractive alternative, particularly for continuous monitoring and point-of-care (POC) testing.1 However, the lack of an exchangeable/disposable sensing element, the resulting memory effect, and the need for frequent recalibration is the main drawback of currently available electrochemical breathalyzers.Herein we examine the feasibility of a POC testing device for aldehyde in exhaled breath to assess the medical application of such a device in noninvasive diagnostic testing for Barrett’s esophagus. To improve the selectivity of the method we harness the unique catalytic activity of the aminoxyl radical/oxoammonium redox couple toward aldehyde oxidation. The highly selective/sensitive device offers the capability for use in the detection of Barrett's esophagus, ideally at early stages, without the need for a high-cost screening test. Our functional sensing element consists of a screen-printed electrode (SPE) in which the graphene oxide-based is the working electrode. Exposing this electrode to simulated breath that contains aldehyde, while applying the required potential for oxidation of the aminoxyl radical (4-acetamido-TEMPO known as ACT), generates an electrocatalytic current proportional to the aldehyde concentration in the breath. These simple, sensitive, durable, and inexpensive electrodes may contribute to the development of a single-use reliable aldehyde sensor for personal or law enforcement applications.1. M. Mayer, M. Rafiee, Electrocatalytic Detection of Ethanol and Acetaldehyde by Aminoxyl Radicals: Utilizing Molecular Catalysis for Breath Analysis. Analyst 147, 2022, 3420 – 3423.