A Novel Wireless Wearable Volatile Organic Compound (VOC) Monitoring Device with Disposable Sensors

abstract: A novel portable wireless volatile organic compound (VOC) monitoring device with disposable sensors is presented. The device is miniaturized, light, easy-to-use, and cost-effective. Different field tests have been carried out to identify the operational, analytical, and functional performance of the device and its sensors. The device was compared to a commercial photo-ionization detector, gas chromatography-mass spectrometry, and carbon monoxide detector. In addition, environmental operational conditions, such as barometric change, temperature change and wind conditions were also tested to evaluate the device performance. The multiple comparisons and tests indicate that the proposed VOC device is adequate to characterize personal exposure in many real-world scenarios and is applicable for personal daily use

A Novel Mobile Device for Environmental Hydrocarbon Sensing and Its Applications

abstract: The accurate and fast determination of organic air pollutants for many applications and studies is critical. Exposure to volatile organic compounds (VOCs) has become an important public health concern, which may induce a lot of health effects such as respiratory irritation, headaches and dizziness. In order to monitor the personal VOCs exposure level at point-of-care, a wearable real time monitor for VOCs detection is necessary. For it to be useful in real world application, it requires low cost, small size and weight, low power consumption, high sensitivity and selectivity. To meet these requirements, a novel mobile device for personal VOCs exposure monitor has been developed. The key sensing element is a disposable molecularly imprinted polymer based quartz tuning fork resonator. The sensor and fabrication protocol are low cost, reproducible and stable. Characterization on the sensing material and device has been done. Comparisons with gold standards in the field such as GC-MS have been conducted. And the device’s functionality and capability have been validated in field tests, proving that it’s a great tool for VOCs monitoring under different scenarios.Dissertation/ThesisDoctoral Dissertation Chemical Engineering 201

Wearable Devices in Health Monitoring from the Environmental towards Multiple Domains: A Survey

The World Health Organization (WHO) recognizes the environmental, behavioral, physiological, and psychological domains that impact adversely human health, well-being, and quality of life (QoL) in general. The environmental domain has significant interaction with the others. With respect to proactive and personalized medicine and the Internet of medical things (IoMT), wearables are most important for continuous health monitoring. In this work, we analyze wearables in healthcare from a perspective of innovation by categorizing them according to the four domains. Furthermore, we consider the mode of wearability, costs, and prolonged monitoring. We identify features and investigate the wearable devices in the terms of sampling rate, resolution, data usage (propagation), and data transmission. We also investigate applications of wearable devices. Web of Science, Scopus, PubMed, IEEE Xplore, and ACM Library delivered wearables that we require to monitor at least one environmental parameter, e.g., a pollutant. According to the number of domains, from which the wearables record data, we identify groups: G1, environmental parameters only; G2, environmental and behavioral parameters; G3, environmental, behavioral, and physiological parameters; and G4 parameters from all domains. In total, we included 53 devices of which 35, 9, 9, and 0 belong to G1, G2, G3, and G4, respectively. Furthermore, 32, 11, 7, and 5 wearables are applied in general health and well-being monitoring, specific diagnostics, disease management, and non-medical. We further propose customized and quantified output for future wearables from both, the perspectives of users, as well as physicians. Our study shows a shift of wearable devices towards disease management and particular applications. It also indicates the significant role of wearables in proactive healthcare, having capability of creating big data and linking to external healthcare systems for real-time monitoring and care delivery at the point of perception

Nanochips and medical applications

Ο όρος «νανοτσιπ» αναφέρεται σε ένα ολοκληρωμένο κύκλωμα (τσιπ) με νανοϋλικά και δομές στη νανοκλίμακα (1-100nm). Ένα ολοκληρωμένο κύκλωμα είναι μια συλλογή ηλεκτρονικών εξαρτημάτων, όπως τρανζίστορ, δίοδοι, πυκνωτές και αντιστάσεις. Τα σημερινά τρανζίστορ είναι στη νανοκλίμακα, αλλά μπορούν να τροποποιηθούν με νανοδομές για την κατασκευή βιοαισθητήρων που μπορούν να πραγματοποιούν ανίχνευση βιομορίων, όπως ιόντα, μόρια DNA, αντισώματα και αντιγόνα με μεγάλη ευαισθησία. Υλικά και Μέθοδοι: Πραγματοποιήθηκε συστηματική αναζήτηση βιβλιογραφίας με χρήση των ηλεκτρονικών βάσεων δεδομένων PubMed, Google Scholar και Scopus για την ανάπτυξη και χρήση νανοτσίπ σε ιατρικές εφαρμογές. Για τον προσδιορισμό των σχετικών εργασιών, τα κριτήρια συμπερίληψης αναφέρονται σε άρθρα στην αγγλική γλώσσα, άρθρα βιβλιογραφικού περιεχομένου ή/και έρευνών. Τα κριτήρια αποκλεισμού ήταν άρθρα εφημερίδων, περιλήψεις συνεδρίων και επιστολές. Αποτελέσματα: Τεχνικές in-vivo και in-vitro έχουν χρησιμοποιηθεί για την ανίχνευση μορίων DNA, ιόντων, αντισωμάτων, σημαντικών πρωτεϊνών και καρκινικών δεικτών, όχι μόνο από δείγματα αίματος αλλά και από ιδρώτα, σάλιο και άλλα βιολογικά υγρά. Διαγνωστική εφαρμογή των νανοτσίπ αποτελεί και η ανίχνευση πτητικών οργανικών ενώσεων μέσω τεστ εκπνεόμενης αναπνοής. Υπάρχουν και αρκετές θεραπευτικές εφαρμογές αυτών των συσκευών ημιαγωγών όπως τσιπ διασύνδεσης εγκεφάλου-υπολογιστή για παραλυτικές ή επιληπτικές καταστάσεις, κατασκευή «βιονικών» οργάνων όπως τεχνητός αμφιβληστροειδής, τεχνητό δέρμα και ρομποτικά προθετικά άκρα για ακρωτηριασμένους ή ρομποτική χειρουργική. Συμπέρασμα: Η χρήση των νανοτσίπ στην ιατρική είναι ένας αναδυόμενος τομέας με αρκετές θεραπευτικές εφαρμογές όπως η διάγνωση, η παρακολούθηση της υγείας και της φυσικής κατάστασης και η κατασκευή «βιονικών» οργάνων.Background: The term “nanochip” pertains to an integrated circuit (chip) with nanomaterials and components in the nano-dimension (1-100nm). An integrated circuit is essentially a collection of electronic components, like transistors, diodes, capacitors, and resistors. Current transistors are in the nanoscale but can also be modified with nanostructures like nanoribbons and nanowires to manufacture biosensors that can perform label-free, ultrasensitive detection of biomolecules like ions, DNA molecules, antibodies and antigens. Materials and Methods: A systematic literature search was conducted using the electronic databases PubMed, Google Scholar and Scopus for the development and use of nanochips in medical applications. For the identification of relevant papers, the inclusion criteria referred to articles in the English language, review and/or research articles. The exclusion criteria were newspaper articles, conference abstracts and letters. Results: In-vivo and In-vitro techniques have been used for detection of DNA molecules, ions, antibodies, important proteins, and tumor markers, not only from blood samples but also from sweat, saliva and other biological fluids. Another diagnostic application of nanochips is detection of volatile organic compounds via a breath test. There are also several therapeutic applications of these semiconductor devices like brain-computer interface chips for paralytic or epileptic conditions, manufacture of “bionic” organs like artificial retinas, artificial skin and robotic prostheses for amputees or robotic surgery. Conclusion: The use of nanochips in medicine is an emerging field with several therapeutic applications like diagnostics, health and fitness monitoring, and manufacture of “bionic” organs

Wearable Nano-Based Gas Sensors for Environmental Monitoring and Encountered Challenges in Optimization

With a rising emphasis on public safety and quality of life, there is an urgent need to ensure optimal air quality, both indoors and outdoors. Detecting toxic gaseous compounds plays a pivotal role in shaping our sustainable future. This review aims to elucidate the advancements in smart wearable (nano)sensors for monitoring harmful gaseous pollutants, such as ammonia (NH3), nitric oxide (NO), nitrous oxide (N2O), nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxide (CO2), hydrogen sulfide (H2S), sulfur dioxide (SO2), ozone (O3), hydrocarbons (CxHy), and hydrogen fluoride (HF). Differentiating this review from its predecessors, we shed light on the challenges faced in enhancing sensor performance and offer a deep dive into the evolution of sensing materials, wearable substrates, electrodes, and types of sensors. Noteworthy materials for robust detection systems encompass 2D nanostructures, carbon nanomaterials, conducting polymers, nanohybrids, and metal oxide semiconductors. A dedicated section dissects the significance of circuit integration, miniaturization, real-time sensing, repeatability, reusability, power efficiency, gas-sensitive material deposition, selectivity, sensitivity, stability, and response/recovery time, pinpointing gaps in the current knowledge and offering avenues for further research. To conclude, we provide insights and suggestions for the prospective trajectory of smart wearable nanosensors in addressing the extant challenges

Biosensors for Diagnosis and Monitoring

Biosensor technologies have received a great amount of interest in recent decades, and this has especially been the case in recent years due to the health alert caused by the COVID-19 pandemic. The sensor platform market has grown in recent decades, and the COVID-19 outbreak has led to an increase in the demand for home diagnostics and point-of-care systems. With the evolution of biosensor technology towards portable platforms with a lower cost on-site analysis and a rapid selective and sensitive response, a larger market has opened up for this technology. The evolution of biosensor systems has the opportunity to change classic analysis towards real-time and in situ detection systems, with platforms such as point-of-care and wearables as well as implantable sensors to decentralize chemical and biological analysis, thus reducing industrial and medical costs. This book is dedicated to all the research related to biosensor technologies. Reviews, perspective articles, and research articles in different biosensing areas such as wearable sensors, point-of-care platforms, and pathogen detection for biomedical applications as well as environmental monitoring will introduce the reader to these relevant topics. This book is aimed at scientists and professionals working in the field of biosensors and also provides essential knowledge for students who want to enter the field

Development of New Generation Chemoresistive VOC/Gas Sensors for Real-Field Applications

Volatile organic compound (VOC) and gas sensors based on semiconducting metal oxides and metal oxide composites have paid much attention since 1960s due to their sensing capability. Compared to conventional methods (e.g., micro-extraction (SPME) and gas chromatography mass spectrometry (GC–MS)) for detecting VOCs and toxic gases, these fabricated devices are anticipated to play a vital role in personal healthcare, environmental protection, securities and industries. Consequently, in recent years, intensive research has been directed to advance their sensing deeds, predominantly to augment the sensitivity and limit of detection for such sensing devices. Besides, sensing technologies become the heart of the future intelligent system due to the prompt enhancement of the Internet of Things (IoT)-enabled real-field applications and associated automation. Sensor devices that can detect trace amounts of VOC/gas analytes presents the favourable ubiquitous nodes of these sensor platforms. For VOC/gas sensing application case selective, highly sensitive, and portable devises are required by employing the various gas sensing materials including metals, carbon nanotubes, conducting polymers, and two-dimensional (2D) materials for meeting the criteria of real-field application. This thesis aims to develop chemoresistive sensors to address the challenges associated with current conventional sensors for VOC/gas detection by employing different fabrication methods. The specific objectives of this thesis are organized into seven chapters that will be presented in the form of a collection of the published papers which are the outcomes of the research. In addition, a literature review has been provided to establish the background of this research, which is also published in a review article. Overall, the main contributions of this thesis to the VOC/gas sensors field are designing and fabricating new sensing devices, and are summarized in following chapters: Chapter 3: Graphene inks for 3D extrusion micro printing of chemo-resistive sensing devices for VOCs detection (paper 1). Chapter 4: Fractal Design for Advancing the Performance of Chemoresistive Sensors (paper 2). Chapter 5: Extrusion printed CNT-graphene sensor array with embedded MXene/PEDOT: PSS heater for enhanced NO2 sensing at low temperature (paper 3). Chapter 6: Fast response hydrogen gas sensor based on Pd/Cr nanogaps fabricated by a single-step bending deformation (paper 4).Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering and Advanced Materials, 202

Chromatographic and sensor-based analysis of skin volatile emissions

Non-invasive techniques for skin analysis including wearable sensor are continuously being explored for their use in personalised healthcare to track movement, blood pressure and heart rate among many other parameters. Recently, focus has shifted towards the development of such wearable sensors for use in biochemical analysis. Accurately diagnosing or predicting the course of an epidermal disease in an individual is challenging due to the complex nature of the skin. Epidermal sensors are a subclass of wearable sensors that are designed to have intimate contact with the skin and are used to monitor physical changes in the skin barrier and detect skin disease biomarkers that can be related to human health. Challenges associated with epidermal sensors is the difficulty of sampling from the skin and also tuning the sensor for the selective detection of a target biomarker or set of biomarkers. The overall aim of this thesis is to investigate the skin volatile emission profile as a potential matrix for analysis and to obtain bio-diagnostic information related to skin health. Chapter 1 of the thesis reviews the literature related to skin structure, function and the methods used for non-invasive skin surface assessment. Chapter 2 explore the potential of using skin volatile samples collected via solid phase micro extraction in a wearable format as a means to assess skin surface pH. Chapter 3 describes the synthesis of a novel dye and the development of dye into a wearable colorimetric skin sensor for the detection of skin emitted volatiles. Although, this sensor is at its early stages of development it has demonstrated selectivity towards skin volatile amines. The work done highlights the possibility of using skin volatiles as a means of assessing skin properties whereby, the measurement of skin surface pH based on the volatile emissions was demonstrated using a wearable colorimetric sensor. Since, skin pH is an important property to monitor for optimal skin barrier function and cutaneous antimicrobial defence, it is envisaged that this sensor could be deployed for health monitoring in the future

Modular Point-of-Care Breath Analyzer and Shape Taxonomy-Based Machine Learning for Gastric Cancer Detection

Funding Information: The development of the analysis approach and its evaluation and analysis were supported by a postdoctoral grant within the Activity 1.1.1.2 “Post-doctoral Research Aid” co-funded by the European Regional Development Fund (postdoctoral project numbers: 1.1.1.2/VIAA/2/18/270 and 1.1.1.2/VIAA/3/19/495). Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Background: Gastric cancer is one of the deadliest malignant diseases, and the non-invasive screening and diagnostics options for it are limited. In this article, we present a multi-modular device for breath analysis coupled with a machine learning approach for the detection of cancer-specific breath from the shapes of sensor response curves (taxonomies of clusters). Methods: We analyzed the breaths of 54 gastric cancer patients and 85 control group participants. The analysis was carried out using a breath analyzer with gold nanoparticle and metal oxide sensors. The response of the sensors was analyzed on the basis of the curve shapes and other features commonly used for comparison. These features were then used to train machine learning models using Naïve Bayes classifiers, Support Vector Machines and Random Forests. Results: The accuracy of the trained models reached 77.8% (sensitivity: up to 66.54%; specificity: up to 92.39%). The use of the proposed shape-based features improved the accuracy in most cases, especially the overall accuracy and sensitivity. Conclusions: The results show that this point-of-care breath analyzer and data analysis approach constitute a promising combination for the detection of gastric cancer-specific breath. The cluster taxonomy-based sensor reaction curve representation improved the results, and could be used in other similar applications.publishersversionPeer reviewe