Electronic nose: a non-invasive technology for breath analysis of diabetes and lung cancer patients

Abstract

In human exhaled breath, more than 3000 volatile organic compounds (VOCs) are found, which are directly or indirectly related to internal biochemical processes in the body. Electronic noses (E-noses) could play a potential role in screening/analyzing various respiratory and systemic diseases by studying breath signatures. An E-nose integrates a sensor array and an artificial neural network that responds to specific patterns of VOCs, and thus can act as a non-invasive technology for disease monitoring. The gold standard blood glucose monitoring test for diabetes diagnostics is invasive and highly uncomfortable. This contributes to the massive need for technologies which are non-invasive and can be used as an alternative to blood measurements for glucose detection. While lung cancer is one of the deadliest cancers with the highest death rate and an extremely high yearly global burden, the conventional diagnosis means, such as sputum cytology, chest radiography, or computed tomography, do not support wide-range population screening. A few standard non-invasive techniques, such as mass spectrometry and gas chromatography, are expensive, non-portable, and require skilled personnel for operation and are again not suitable for large-scale screening. Breath contains markers for both diabetes and lung cancer along with markers for several diseases and thus, a non-invasive technique such as the E-nose would greatly improve analysis procedures over existing invasive methods. This review shows the state-of-the-art technologies for VOC detection and machine learning approaches for two clinical models: diabetes and lung cancer detection.

Emerging non‑invasive detection methodologies for lung cancer (Review)

“…Mass spectrometry-based techniques are expensive and require complex instruments. By contrast, sensors/E-noses show great potential for fast, easy and cost-effective diagnosis and screening of LC (67). With the advancement of sensing devices, electronics and signal processing, the sizes of sensors/E-nose systems can be minimized along with fast data processing to provide real-time results (67).…”

A Low-Cost Breath Analyzer Module in Domiciliary Non-Invasive Mechanical Ventilation for Remote COPD Patient Monitoring

“…A lot of efforts are devoted to get technological advances developing novel analytical and sensing platforms. Despite the difficulties in implementing breath-based diagnostics in daily clinical practice, scientific community believe that breath analysis will realize its long-held potential becoming a revolutionary tool in personalized medicine [40][41][42][43]. Breathomics studies applied to COPD showed distinct patterns of exhaled volatiles in COPD patients supporting the potential use of VOCs in discriminating COPD subjects and healthy controls as well as in identifying clinically relevant COPD subgroups [44][45][46].…”

“…Although the various forms of mass spectrometry, mainly gas chromatography-MS (GC-MS), proton transfer reaction-MS (PTR-MS), selected ion flow tube-MS (SIFT-MS) [50], provide information on exhaled substances with molecular identification and quantification, other more flexible, cheap and functional sensing platforms are electronic noses (e-noses). Such devices fingerprint the ensemble of exhaled VOCs (called human exhalome) in terms of gas/VOC sensors response patterns; their challenge is to become a screening non-invasive technique supporting gold mass spectrometric techniques [40,41,[51][52][53][54].…”

The electronic nose: emerging biomarkers in lung cancer diagnostics

“…VOCs were identified in the 1970s [11]. Since then, breath analysis has boomed into a high-throughput breathomics research field with >3000 different VOCs discovered in human breath [12,13]. Most particles in the air are biogenic and emitted through external processes such as the environment and atmospheric pollution [10].…”

“…Most particles in the air are biogenic and emitted through external processes such as the environment and atmospheric pollution [10]. However, due to metabolic processes within the human body, VOCs can be emitted or VOC patterns can be altered [13]. These processes can be physiological but can be also induced by or altered due to disease.…”