More Like this

1. A Comprehensive Review of Biomarker Sensors for a Breathalyzer Platform

   https://doi.org/10.3390/s24227263  

   Sadeghi, Pardis; Alshawabkeh, Rania; Rui, Amie; Sun, Nian Xiang (November 2024, Sensors)

   Detecting volatile organic compounds (VOCs) is increasingly recognized as a pivotal tool in non-invasive disease diagnostics. VOCs are metabolic byproducts, mostly found in human breath, urine, feces, and sweat, whose profiles may shift significantly due to pathological conditions. This paper presents a thorough review of the latest advancements in sensor technologies for VOC detection, with a focus on their healthcare applications. It begins by introducing VOC detection principles, followed by a review of the rapidly evolving technologies in this area. Special emphasis is given to functionalized molecularly imprinted polymer-based biochemical sensors for detecting breath biomarkers, owing to their exceptional selectivity. The discussion examines SWaP-C considerations alongside the respective advantages and disadvantages of VOC sensing technologies. The paper also tackles the principal challenges facing the field and concludes by outlining the current status and proposing directions for future research. 

   more » « less
2. Advancements in miniaturized infrared spectroscopic-based volatile organic compound sensors: A systematic review

   https://doi.org/10.1063/5.0197236  

   Xia, Lipeng; Liu, Yuheng; Chen, Ray T; Weng, Binbin; Zou, Yi (September 2024, Applied Physics Reviews)

   The global trends of urbanization and industrialization have given rise to critical environmental and air pollution issues that often receive insufficient attention. Among the myriad pollution sources, volatile organic compounds (VOCs) stand out as a primary cluster, posing a significant threat to human society. Addressing VOCs emissions requires an effective mitigation action plan, placing technological development, especially in detection, at the forefront. Photonic sensing technologies rooted in the infrared (IR) light and matter interaction mechanism offer nondestructive, fast-response, sensitive, and selective chemical measurements, making them a promising solution for VOC detection. Recent strides in nanofabrication processes have facilitated the development of miniaturized photonic devices and thus sparked growing interest in the creation of low-cost, highly selective, sensitive, and fast-response IR optical sensors for VOC detection. This review work thus serves a timely need to provide the community a comprehensive understanding of the state of the art in this field and illuminate the path forward in addressing the pressing issue of VOC pollution. 

   more » « less
3. Reduced Graphene Oxide-Metalloporphyrin Sensors for Human Breath Screening

   https://doi.org/10.3390/app112311290  

   Lee, Bo Mi; Eetemadi, Ameen; Tagkopoulos, Ilias (December 2021, Applied Sciences)

   The objective of this study is to validate reduced graphene oxide (RGO)-based volatile organic compounds (VOC) sensors, assembled by simple and low-cost manufacturing, for the detection of disease-related VOCs in human breath using machine learning (ML) algorithms. RGO films were functionalized by four different metalloporphryins to assemble cross-sensitive chemiresistive sensors with different sensing properties. This work demonstrated how different ML algorithms affect the discrimination capabilities of RGO–based VOC sensors. In addition, an ML-based disease classifier was derived to discriminate healthy vs. unhealthy individuals based on breath sample data. The results show that our ML models could predict the presence of disease-related VOC compounds of interest with a minimum accuracy and F1-score of 91.7% and 83.3%, respectively, and discriminate chronic kidney disease breath with a high accuracy, 91.7%. 

   more » « less
4. Volatile Organic Compounds Modulate the Biological and Chemical Environment of the Phycosphere

   Padaki, Vaishnavi G (May 2025, ScholarsArchive@OSU)

   The ocean is a vast reservoir of bioavailable dissolved organic compounds (DOCs). Phytoplankton and bacterioplankton are the primary producers and consumers of these organic compounds, respectively, driving DOCs turnover on timescales of minutes to days. Volatile organic compounds (VOCs) make up about a third of DOCs, and their diffusivity and reactivity cause them to be important contributors to plankton carbon cycling and atmospheric chemistry. This research sought to describe plankton interactions mediated by VOCs. A model diatom, Phaeodactylum tricornutum, and five bacterial species known to be associated with the P. tricornutum phycosphere were studied in monocultures and co-cultures. Investigations evaluated the VOCs produced and consumed, temporal dynamics of VOC production and their roles in diatom metabolism, and physiological strategies of bacterial VOC consumers. P. tricornutum produced 78 VOCs during exponential growth. About 60% of these VOCs were hydrocarbons. In co-cultures with P. tricornutum, bacteria consumed different ranges of VOCs. The VOC specialists, Marinobacter and Roseibium, consumed the most, had hydrocarbon oxidation genes, and showed motility and physical attachment to the diatom. Rhodobacter and Stappia consumed fewer VOCs and were non-motile, while Yoonia consumed only acetaldehyde. Diatom gross carbon fixation was 29% higher in the presence of VOC specialists, suggesting rapid VOC consumption in the phycosphere impacts global gross carbon production. Temporal VOC production in P. tricornutum was monitored over a diel cycle. All VOCs were produced in higher concentrations during the day compared to night. Regression spline functions revealed six unique temporal production patterns associated with diel shifts in metabolism and the cell cycle. Physiological strategies for VOC uptake were studied in the VOC specialist Marinobacter. Marinobacter consumed some benzenoids at concentrations ranging from pM to μM and most increased cell densities compared to no VOC added controls and were not chemoattractants. Other VOCs that did not stimulate higher cell densities were strong chemoattractants. Thus, some VOCs are chemoattractants that guide motile cells toward co-emitted growth substrates. VOC discrimination may optimize spatial and temporal positioning in the phycosphere and enhance VOC uptake, sustaining the extremely low VOC concentrations in the surface ocean. This research revealed phytoplankton and ii bacterioplankton physiological processes that underlie the biological cycling of surface ocean VOCs and their potential for air-sea flux. This dissertation on microbiology in the phycosphere provided a foundation for exploring elements of science art that promote audience engagement through an exhibition that used scientific findings from the dissertation. Original art and audience surveys were used iteratively to increase science accessibility to general audiences. 

   more » « less
5. Contextual Attention for Hand Detection in the Wild

   Narasimhaswamy, S. (October 2019, IEEE International Conference on Computer Vision workshops)

   We present Hand-CNN, a novel convolutional network architecture for detecting hand masks and predicting hand orientations in unconstrained images. Hand-CNN extends MaskRCNN with a novel attention mechanism to incorporate contextual cues in the detection process. This attention mechanism can be implemented as an efficient network module that captures non-local dependencies between features. This network module can be inserted at different stages of an object detection network, and the entire detector can be trained end-to-end. We also introduce a large-scale annotated hand dataset containing hands in unconstrained images for training and evaluation. We show that Hand-CNN outperforms existing methods on several datasets, including our hand detection benchmark and the publicly available PASCAL VOC human layout challenge. We also conduct ablation studies on hand detection to show the effectiveness of the proposed contextual attention module. 

   more » « less