Development of a compact, IoT-enabled electronic nose for breath analysis

In this paper, we report on an in-house developed electronic nose (E-nose) for use with breath analysis. The unit consists of an array of 10 micro-electro-mechanical systems (MEMS) metal oxide (MOX) gas sensors produced by seven manufacturers. Breath sampling of end-tidal breath is achieved using a heated sample tube, capable of monitoring sampling-related parameters, such as carbon dioxide (CO2), humidity, and temperature. A simple mobile app was developed to receive real-time data from the device, using Wi-Fi communication. The system has been tested using chemical standards and exhaled breath samples from healthy volunteers, before and after taking a peppermint capsule. Results from chemical testing indicate that we can separate chemical standards (acetone, isopropanol and 1-propanol) and different concentrations of isobutylene. The analysis of exhaled breath samples demonstrate that we can distinguish between pre- and post-consumption of peppermint capsules; area under the curve (AUC): 0.81, sensitivity: 0.83 (0.59–0.96), specificity: 0.72 (0.47–0.90), p-value: <0.001. The functionality of the developed device has been demonstrated with the testing of chemical standards and a simplified breath study using peppermint capsules. It is our intention to deploy this system in a UK hospital in an upcoming breath research study

Review—Non-Invasive Monitoring of Human Health by Exhaled Breath Analysis: A Comprehensive Review

Exhaled human breath analysis is a very promisingfield of research work having great potential for diagnosis of diseases in non-invasive way. Breath analysis has attracted huge attention in thefield of medical diagnosis and disease monitoring in the last twodecades. VOCs/gases (Volatile Organic Compounds) in exhaled breath bear thefinger-prints of metabolic and biophysicalprocesses going on in human body. It’s a non-invasive, fast, non-hazardous, cost effective, and point of care process for diseasestate monitoring and environmental exposure assessment in human beings. Some VOCs/gases in exhaled breath are bio-markers ofdifferent diseases and their presence in excess amount is indicative of un-healthiness. Breath analysis has the potential for earlydetection of diseases. However, it is still underused and commercial device is yet not available owing to multiferrious challenges.This review is intended to provide an overview of major biomarkers (VOCs/gases) present in exhaled breath, importance of theiranalysis towards disease monitoring, analytical techniques involved, promising materials for breath analysis etc. Finally, relatedchallenges and limitations along with future scope will be touched upon.will be touched upon

Using Volatile Organic Compounds In Exhaled Breath As A Biomarker For Early Lung Cancer Detection: A Systematic Review

Lung cancer has become the most commonly diagnosed cancer and the leading cause of cancer deaths globally. The major problem of the high mortality rate is the late diagnosis. Conventional methods utilized for clinical detection of lung cancer have employed expensive and invasive medical procedures that cause stress, discomfort, and pain to patients, and have demonstrated low sensitivity, substantial false negatives, and risk of radiation exposure. The drawbacks obviate their applicability to large-scale, population-wide screening efforts. This paper reviews the applications of using volatile organic compounds (VOCs) in exhaled breath as a potential approach for early lung cancer detection. An electronic search was conducted in PubMed and Scopus. A total of 41 studies were included in this review. The sampling method of exhaled breath employed in most of the included studies were leak-proof Tedlar bags. Mass spectrometry and electronic noses were two main techniques used in breath sample detection. In the recent years, electronic noses gained more popularity due to their portability and cost-effectiveness. In this review, a total of 40 VOCs, originated from both endogenous and exogenous sources, were found to be significant in discriminating between lung cancer patients and healthy controls in two or more of the included studies. The included studies demonstrated substantial sensitivity, specificity, and accuracy of the method. Overall, the results showed that VOCs in exhaled breath is a promising biomarker for early detection of lung cancer. However, the large-scale practice of this method is constrained by the lack of standardized breath collection and analysis system and putative exhaled VOC biomarkers. Further studies with consistent sampling protocols should be used to demonstrate the reproducibility and repeatability of the detection tool before they are applied in clinical practice

Advances in Electronic-Nose Technologies Developed for Biomedical Applications

The research and development of new electronic-nose applications in the biomedical field has accelerated at a phenomenal rate over the past 25 years. Many innovative e-nose technologies have provided solutions and applications to a wide variety of complex biomedical and healthcare problems. The purposes of this review are to present a comprehensive analysis of past and recent biomedical research findings and developments of electronic-nose sensor technologies, and to identify current and future potential e-nose applications that will continue to advance the effectiveness and efficiency of biomedical treatments and healthcare services for many years. An abundance of electronic-nose applications has been developed for a variety of healthcare sectors including diagnostics, immunology, pathology, patient recovery, pharmacology, physical therapy, physiology, preventative medicine, remote healthcare, and wound and graft healing. Specific biomedical e-nose applications range from uses in biochemical testing, blood-compatibility evaluations, disease diagnoses, and drug delivery to monitoring of metabolic levels, organ dysfunctions, and patient conditions through telemedicine. This paper summarizes the major electronic-nose technologies developed for healthcare and biomedical applications since the late 1980s when electronic aroma detection technologies were first recognized to be potentially useful in providing effective solutions to problems in the healthcare industry

Electronic nose for analysis of volatile organic compounds in air and exhaled breath.

Exhaled breath is a complex mixture containing numerous volatile organic compounds (VOCs) at trace levels (ppb to ppt) including hydrocarbons, alcohols, ketones, aldehydes, esters and other non-volatile compounds. Different patterns of VOCs have been correlated with various diseases. The concentration levels of VOCs in exhaled breath depend on an individual subject’s health status. Therefore, breath analysis has great potential for clinical diagnostics, monitoring therapeutic progress and drug metabolic products. Even though up to 3000 compounds may be detected in breath, the matrix of exhaled breath is less complex than that of blood or other body fluids. Breath analysis can be performed on people irrespective of age, gender, lifestyle, or other confounding factors. Breath gas concentration can be related to VOC concentrations in blood via mathematical modeling; for example, as in blood alcohol testing. Since exhaled breath samples are easy to collect and online instruments are commercially available, VOC analysis in exhaled breath appears to be a promising tool for noninvasive detection and monitoring of diseases. Breath analysis has been very successful in identifying cancer, diabetes and other diseases by using a chemiresistor sensor array to detect biomarkers. The objective of this research project is to develop sensor arrays ― or so-called electronic nose ― for analysis of VOCs in air and exhaled breath. In this dissertation, we have investigated both commercial and synthesized thiol functionalized gold nanoparticles (AuNPs) as sensing materials for analysis of VOCs in air and exhaled breath. The advantages of these sensors include very high sensitivity, selectivity for detection of target analytes and operation at ambient temperature. The synthesis and material characterization of new thiols and AuNPs for increasing sensitivity and selectivity have been studied. Selected commercial thiols and in-house synthesized new functional thiols have been used to modify AuNP-based sensors for detection of VOCs in air and exhaled breath. The interdigitated electrodes (IDE) used for the sensors were fabricated by microelectromechanical systems (MEMS) microfabrication technologies. The sensor arrays were characterized by measuring the resistance difference from vacuum and different spiked analyte concentrations in air and breath samples. Air samples and breath samples were collected using Tedlar bags, and analyzed using the thiol functionalized AuNP sensors. The analysis of air samples provides a reference for analysis of exhaled breath samples. The sensors have demonstrated a low detection limit of 0.1 ppbv of acetone and ethanol in dry air and exhaled breath. The concentrations of acetone in air and exhaled breath were determined by a silicon microreactor approach. The measurements of acetone by the microreactor approach were correlated with the sensor signals. The intellectual thrust of this research is the rational design of an electronic nose for analysis of VOCs in exhaled breath, which offers a new frontier in medical diagnostics because of its non-invasive and inexpensive characteristics

Electronic Noses for Biomedical Applications and Environmental Monitoring

This book, titled “Electronic Noses for Biomedical Applications and Environmental Monitoring”, includes original research works and reviews concerning the use of electronic nose technology in two of the more useful and interesting fields related to chemical compounds detection of gases. Authors have explained their latest research work, including different gas sensors and materials based on nanotechnology and novel applications of electronic noses for the detection of diverse diseases. Some reviews related to disease detection through breath analysis, odor monitoring systems standardization, and seawater quality monitoring are also included

Metal Oxide-based Gas Sensor Array for the VOCs Analysis in Complex Mixtures using Machine Learning

Detection of Volatile Organic Compounds (VOCs) from the breath is becoming a viable route for the early detection of diseases non-invasively. This paper presents a sensor array with three metal oxide electrodes that can use machine learning methods to identify four distinct VOCs in a mixture. The metal oxide sensor array was subjected to various VOC concentrations, including ethanol, acetone, toluene and chloroform. The dataset obtained from individual gases and their mixtures were analyzed using multiple machine learning algorithms, such as Random Forest (RF), K-Nearest Neighbor (KNN), Decision Tree, Linear Regression, Logistic Regression, Naive Bayes, Linear Discriminant Analysis, Artificial Neural Network, and Support Vector Machine. KNN and RF have shown more than 99% accuracy in classifying different varying chemicals in the gas mixtures. In regression analysis, KNN has delivered the best results with R2 value of more than 0.99 and LOD of 0.012, 0.015, 0.014 and 0.025 PPM for predicting the concentrations of varying chemicals Acetone, Toluene, Ethanol, and Chloroform, respectively in complex mixtures. Therefore, it is demonstrated that the array utilizing the provided algorithms can classify and predict the concentrations of the four gases simultaneously for disease diagnosis and treatment monitoring

Sensor Technology for Opening New Pathways in Diagnosis and Therapeutics of Breast, Lung, Colorectal and Prostate Cancer

This study analyzes the interaction between sensor research and technology and different types of cancer (breast, lung, colorectal, and prostate) with the goal of detecting new directions for improving diagnosis and therapeutics in medicine. This study develops an approach to computational scientometrics based on data from the Web of Science from the 1991 to 2021 period. The results of this analysis show the vital role of biosensors and electrochemical biosensors applied in breast cancer, lung cancer, and prostate cancer research. Instead, scientific research of optical sensors is developing main technological trajectories in breast, prostate, and colorectal cancer for improving diagnostics. Finally, oxygen sensor research has a main technological development in breast and lung cancer for new applications in breath analysis directed to treatment processes. Preliminary results presented here clearly illustrate the evolutionary paths of sensor research and technologies that have great potential for developing incremental and radical innovations in cancer diagnosis and therapies. These conclusions are, of course, tentative. There is a need for much more detailed research based on other aspects and factors for detecting stable technological trajectories that can foster the technology transfer of new sensor in cancer research for improving diagnosis and therapeutics, reducing, whenever possible, world-wide mortality of cancer in society.JEL Classification: I10, O30, O31, O32; O33. Doi: 10.28991/HIJ-2022-03-03-010 Full Text: PD

Gas sensing technologies -- status, trends, perspectives and novel applications

The strong, continuous progresses in gas sensors and electronic noses resulted in improved performance and enabled an increasing range of applications with large impact on modern societies, such as environmental monitoring, food quality control and diagnostics by breath analysis. Here we review this field with special attention to established and emerging approaches as well as the most recent breakthroughs, challenges and perspectives. In particular, we focus on (1) the transduction principles employed in different architectures of gas sensors, analysing their advantages and limitations; (2) the sensing layers including recent trends toward nanostructured, low-dimensional and composite materials; (3) advances in signal processing methodologies, including the recent advent of artificial neural networks. Finally, we conclude with a summary on the latest achievements and trends in terms of applications.Comment: arXiv admin comment: This version has been removed by arXiv administrators as the submitter did not have the rights to agree to the license at the time of submissio