Graphene in plastic packages: A low cost construction method for resistive chemical sensors

2012 ◽  
Vol 1407 ◽  
Author(s):  
Silpa Kona ◽  
Cindy K Harnett
Keyword(s):  
Chemical Sensors ◽  
Carbon Materials ◽  
Low Cost ◽  
High Sensitivity ◽  
Cost Effective ◽  
Sensing Element ◽  
Graphene Surface ◽  
Plastic Packages ◽  
Surface Adsorbates ◽  
Gas Molecules

ABSTRACTThe discovery of carbon nanotubes and subsequently graphene has led to an interest in carbon materials as sensing elements due to their unique properties. Graphene is a 2-dimensional material that has a large surface area (~2630 m2g-1) that can be exposed to surface adsorbates from a target gas. This enables studies on the interaction of gas molecules with the graphene surface and resulting changes in its properties, making graphene an excellent sensing element. We present our graphene based sensor with the focus on designing small, cost effective and reliable sensors with high sensitivity towards the target gas, detailing the assembly of graphene/acrylic based devices, their characterization and investigation of their performance as resistive chemical sensors

scholarly journals 60–700 K CTAT and PTAT Temperature Sensors with 4H-SiC Schottky Diodes

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 942
Author(s):  
Razvan Pascu ◽  
Gheorghe Pristavu ◽  
Gheorghe Brezeanu ◽  
Florin Draghici ◽  
Philippe Godignon ◽  
...  
Keyword(s):  
Low Cost ◽  
Schottky Diodes ◽  
Schottky Contact ◽  
High Sensitivity ◽  
Xrd Analysis ◽  
Absolute Temperature ◽  
Lower Sensitivity ◽  
Readout Circuit ◽  
Sensing Element ◽  
High Performing

A SiC Schottky dual-diode temperature-sensing element, suitable for both complementary variation of VF with absolute temperature (CTAT) and differential proportional to absolute temperature (PTAT) sensors, is demonstrated over 60–700 K, currently the widest range reported. The structure’s layout places the two identical diodes in close, symmetrical proximity. A stable and high-barrier Schottky contact based on Ni, annealed at 750 °C, is used. XRD analysis evinced the even distribution of Ni2Si over the entire Schottky contact area. Forward measurements in the 60–700 K range indicate nearly identical characteristics for the dual-diodes, with only minor inhomogeneity. Our parallel diode (p-diode) model is used to parameterize experimental curves and evaluate sensing performances over this far-reaching domain. High sensitivity, upwards of 2.32 mV/K, is obtained, with satisfactory linearity (R2 reaching 99.80%) for the CTAT sensor, even down to 60 K. The PTAT differential version boasts increased linearity, up to 99.95%. The lower sensitivity is, in this case, compensated by using a high-performing, low-cost readout circuit, leading to a peak 14.91 mV/K, without influencing linearity.

scholarly journals Simple, sensitive and cost-effective detection of wAlbB Wolbachia in Aedes mosquitoes, using loop mediated isothermal amplification combined with the electrochemical biosensing method

2021 ◽  
Author(s):  
Pattamaporn Kittayapong ◽  
Parinda Thayanukul ◽  
Benchaporn Lertanantawong ◽  
Worachart Sirawaraporn ◽  
Surat Charasmongkolcharoen ◽  
...  
Keyword(s):  
Low Cost ◽  
High Sensitivity ◽  
Cost Effective ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Control Programs ◽  
Electrochemical Biosensing ◽  
Dna Strand Displacement ◽  
Displacement Based ◽  
Dna Strand

Background Wolbachia is an endosymbiont bacterium generally found in about 40% of insects, including mosquitoes, but it is absent in Aedes aegypti which is an important vector of several arboviral diseasesdengue, chikungunya, Zika, and yellow fever. The evidence that Wolbachia trans-infected Ae. aegypti mosquitoes lost their vectorial competence and became less capable of transmitting arboviruses to human hosts highlights the potential of using Wolbachia - based approaches for prevention and control of arboviral diseases. Recently, release of Wolbachia trans-infected Ae. aegypti has been deployed widely in many countries for the control of mosquito-borne viral diseases. Field surveillance and monitoring of Wolbachia presence in released mosquitoes is important for the success of these control programs. So far, a number of studies have reported the development of loop mediated isothermal amplification (LAMP) assays to detect Wolbachia in mosquitoes, but the methods still have some specificity issues. Methodology/Principal Findings We describe here the development of a LAMP combined with the DNA strand displacement-based electrochemical sensor (BIOSENSOR) method to detect wAlbB Wolbachia in trans-infected Ae . aegypti . Our developed LAMP primers were more specific to wAlbB detection than those of the previous published ones if  the assays were conducted with low-cost and non-specific detecting dyes. The detection capacity of our LAMP technique was 3.8 nM and the detection limit reduced to 2.16 fM when combined with the BIOSENSOR. Our study demonstrates that the BIOSENSOR can also be applied as a stand-alone method for detecting Wolbachia ; and it showed high sensitivity when used with the crude DNA extracts of macerated mosquito samples without DNA purification. Conclusions/Significance Our results suggest that both LAMP and BIOSENSOR, either used in combination or stand-alone, are robust and sensitive. The methods have good potential for routine detection of Wolbachia in mosquitoes during field surveillance and monitoring of Wolbachia -based release programs, especially in countries with limited resources.

scholarly journals Microwave Spoof Surface Plasmon Polariton-Based Sensor for Ultrasensitive Detection of Liquid Analyte Dielectric Constant

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5477
Author(s):  
Ivana Podunavac ◽  
Vasa Radonic ◽  
Vesna Bengin ◽  
Nikolina Jankovic
Keyword(s):  
Dielectric Constant ◽  
Surface Plasmon ◽  
Edible Oils ◽  
Low Cost ◽  
High Sensitivity ◽  
Cost Effective ◽  
Ultrasensitive Detection ◽  
Sensing Platform ◽  
Excellent Candidate ◽  
Plasmon Polaritons

In this paper, a microwave microfluidic sensor based on spoof surface plasmon polaritons (SSPPs) was proposed for ultrasensitive detection of dielectric constant. A novel unit cell for the SSPP structure is proposed and its behaviour and sensing potential analysed in detail. Based on the proposed cell, the SSPP microwave structure with a microfluidic reservoir is designed as a multilayer configuration to serve as a sensing platform for liquid analytes. The sensor is realized using a combination of rapid, cost-effective technologies of xurography, laser micromachining, and cold lamination bonding, and its potential is validated in the experiments with edible oil samples. The results demonstrate high sensitivity (850 MHz/epsilon unit) and excellent linearity (R2 = 0.9802) of the sensor, which, together with its low-cost and simple fabrication, make the proposed sensor an excellent candidate for the detection of small changes in the dielectric constant of edible oils and other liquid analytes.

scholarly journals Carbon Materials in Electroanalysis of Preservatives: A Review

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7630
Author(s):  
Slawomir Michalkiewicz ◽  
Agata Skorupa ◽  
Magdalena Jakubczyk
Keyword(s):  
Carbon Materials ◽  
Electrochemical Sensors ◽  
Low Cost ◽  
Pharmaceutical Preparations ◽  
High Sensitivity ◽  
Potential Range ◽  
Nonaqueous Media ◽  
Voltammetric Analysis ◽  
Materials Used ◽  
Voltammetric Methods

Electrochemical sensors in electroanalysis are a particularly useful and relatively simple way to identify electroactive substances. Among the materials used to design sensors, there is a growing interest in different types of carbon. This is mainly due to its non-toxic properties, low cost, good electrical conductivity, wide potential range, and the possibility of using it in both aqueous and nonaqueous media. The electrodes made of carbon, and especially of carbon modified with different materials, are currently most often used in the voltammetric analysis of various compounds, including preservatives. The objective of this paper is to present the characteristics and suitability of different carbon materials for the construction of working electrodes used in the voltammetric analysis. Various carbon materials were considered and briefly discussed. Their analytical application was presented on the example of the preservatives commonly used in food, cosmetic, and pharmaceutical preparations. It was shown that for the electroanalysis of preservatives, mainly carbon electrodes modified with various modifiers are used. These modifications ensure appropriate selectivity, high sensitivity, low limits of detection and quantification, as well as a wide linearity range of voltammetric methods of their identification and determination.

scholarly journals Detection of Contaminants in Hydrogen Fuel for Fuel Cell Electrical Vehicles with Sensors—Available Technology, Testing Protocols and Implementation Challenges

Processes ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 20
Author(s):  
Karine Arrhenius ◽  
Thomas Bacquart ◽  
Karin Schröter ◽  
Martine Carré ◽  
Bruno Gozlan ◽  
...  
Keyword(s):  
Quality Control ◽  
Standardized Testing ◽  
Chemical Sensors ◽  
Low Cost ◽  
Control Process ◽  
High Sensitivity ◽  
Low Carbon ◽  
Hydrogen Fuel ◽  
Quality Control Process ◽  
Testing Protocols

Europe’s low-carbon energy policy favors a greater use of fuel cells and technologies based on hydrogen used as a fuel. Hydrogen delivered at the hydrogen refueling station must be compliant with requirements stated in different standards. Currently, the quality control process is performed by offline analysis of the hydrogen fuel. It is, however, beneficial to continuously monitor at least some of the contaminants onsite using chemical sensors. For hydrogen quality control with regard to contaminants, high sensitivity, integration parameters, and low cost are the most important requirements. In this study, we have reviewed the existing sensor technologies to detect contaminants in hydrogen, then discussed the implementation of sensors at a hydrogen refueling stations, described the state-of-art in protocols to perform assessment of these sensor technologies, and, finally, identified the gaps and needs in these areas. It was clear that sensors are not yet commercially available for all gaseous contaminants mentioned in ISO14687:2019. The development of standardized testing protocols is required to go hand in hand with the development of chemical sensors for this application following a similar approach to the one undertaken for air sensors.

scholarly journals Deep Learning-Enabled Point-of-Care Sensing Using Multiplexed Paper-Based Sensors

2019 ◽  
Author(s):  
Zachary Ballard ◽  
Hyou-Arm Joung ◽  
Artem Goncharov ◽  
Jesse Liang ◽  
Karina Nugroho ◽  
...  
Keyword(s):  
Machine Learning ◽  
Deep Learning ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
Cost Effective ◽  
Serum Samples ◽  
Cvd Risk ◽  
Medical Test ◽  
Sensing Membrane

ABSTRACTWe present a deep learning-based framework to design and quantify point-of-care sensors. As its proof-of-concept and use-case, we demonstrated a low-cost and rapid paper-based vertical flow assay (VFA) for high sensitivity C-Reactive Protein (hsCRP) testing, a common medical test used for quantifying the degree of inflammation in patients at risk of cardio-vascular disease (CVD). A machine learning-based sensor design framework was developed for two key tasks: (1) to determine an optimal configuration of immunoreaction spots and conditions, spatially-multiplexed on a paper-based sensing membrane, and (2) to accurately infer the target analyte concentration based on the signals of the optimal VFA configuration. Using a custom-designed mobile-phone based VFA reader, a clinical study was performed with 85 human serum samples to characterize the quantification accuracy around the clinically defined cutoffs for CVD risk stratification. Results from blindly-tested VFAs indicate a competitive coefficient of variation of 11.2% with a linearity of R2 = 0.95; in addition to the success in the high-sensitivity CRP range (i.e., 0-10 mg/L), our results further demonstrate a mitigation of the hook-effect at higher CRP concentrations due to the incorporation of antigen capture spots within the multiplexed sensing membrane of the VFA. This paper-based computational VFA that is powered by deep learning could expand access to CVD health screening, and the presented machine learning-enabled sensing framework can be broadly used to design cost-effective and mobile sensors for various point-of-care diagnostics applications.

scholarly journals Reversible Room Temperature H2 Gas Sensing Based on Self-Assembled Cobalt Oxysulfide

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 303
Author(s):  
Hui Zhou ◽  
Kai Xu ◽  
Nam Ha ◽  
Yinfen Cheng ◽  
Rui Ou ◽  
...  
Keyword(s):  
Room Temperature ◽  
Elevated Temperatures ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Cobalt Sulfide ◽  
Bandgap Energy ◽  
Gas Molecules ◽  
Self Assembled ◽  
P Type

Reversible H2 gas sensing at room temperature has been highly desirable given the booming of the Internet of Things (IoT), zero-emission vehicles, and fuel cell technologies. Conventional metal oxide-based semiconducting gas sensors have been considered as suitable candidates given their low-cost, high sensitivity, and long stability. However, the dominant sensing mechanism is based on the chemisorption of gas molecules which requires elevated temperatures to activate the catalytic reaction of target gas molecules with chemisorbed O, leaving the drawbacks of high-power consumption and poor selectivity. In this work, we introduce an alternative candidate of cobalt oxysulfide derived from the calcination of self-assembled cobalt sulfide micro-cages. It is found that the majority of S atoms are replaced by O in cobalt oxysulfide, transforming the crystal structure to tetragonal coordination and slightly expanding the optical bandgap energy. The H2 gas sensing performances of cobalt oxysulfide are fully reversible at room temperature, demonstrating peculiar p-type gas responses with a magnitude of 15% for 1% H2 and a high degree of selectivity over CH4, NO2, and CO2. Such excellent performances are possibly ascribed to the physisorption dominating the gas–matter interaction. This work demonstrates the great potentials of transition metal oxysulfide compounds for room-temperature fully reversible gas sensing.

scholarly journals A new Syber Green real time PCR to detect SARS-CoV-2

2020 ◽  
Author(s):  
D.R. Marinowic ◽  
G. Zanirati ◽  
F.V.F. Rodrigues ◽  
M.V.C. Grahl ◽  
A.M. Alcará ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Large Scale ◽  
Low Cost ◽  
Phylogenetic Analyses ◽  
High Sensitivity ◽  
High Specificity ◽  
Cost Effective ◽  
Etiologic Agent ◽  
Rt Pcr ◽  
Human Respiratory Tract

Abstract Phylogenetic analyses demonstrated that etiologic agent of pandemic outbreak is a betacoronavirus named SARS-CoV-2. For public health interventions, a diagnostic test with high sensitivity and specificity is required. The gold standard protocol for diagnosis by WHO is the RT-PCR. To detect low viral load and large-scale screening a low-cost diagnostic test becomes necessary. Here we develop a cost-effective test capable of to detect the new coronavirues. We validated an auxiliary protocol for molecular diagnosis with RT-PCR SYBR Green methodology to successfully screen negative cases of SARS-CoV-2. Our results demonstrated that a set of primers with high specificity, and no homology with other viruses from Coronovideae family or human respiratory tract pathogenic viruses. Optimization of annealing temperature and polymerization time led to an high specificity in the PCR products. We have developed a more affordable and swift methodology for negative SARS-CoV-2 screening. This methodology can be applied on large scale populational to soften panic and economic burden through guidance for isolation strategies.

scholarly journals A new SYBR Green real-time PCR to detect SARS-CoV-2

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
D. R. Marinowic ◽  
G. Zanirati ◽  
F. V. F. Rodrigues ◽  
M. V. C. Grahl ◽  
A. M. Alcará ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Large Scale ◽  
Low Cost ◽  
High Sensitivity ◽  
High Specificity ◽  
Cost Effective ◽  
Etiologic Agent ◽  
Sybr Green ◽  
Rt Pcr ◽  
Human Respiratory Tract

AbstractPhylogenetic analysis has demonstrated that the etiologic agent of the 2020 pandemic outbreak is a betacoronavirus named SARS-CoV-2. For public health interventions, a diagnostic test with high sensitivity and specificity is required. The gold standard protocol for diagnosis by the Word Health Organization (WHO) is RT-PCR. To detect low viral loads and perform large-scale screening, a low-cost diagnostic test is necessary. Here, we developed a cost-effective test capable of detecting SARS-CoV-2. We validated an auxiliary protocol for molecular diagnosis with the SYBR Green RT-PCR methodology to successfully screen negative cases of SARS-CoV-2. Our results revealed a set of primers with high specificity and no homology with other viruses from the Coronovideae family or human respiratory tract pathogenic viruses, presenting with complementarity only for rhinoviruses/enteroviruses and Legionella spp. Optimization of the annealing temperature and polymerization time led to a high specificity in the PCR products. We have developed a more affordable and swift methodology for negative SARS-CoV-2 screening. This methodology can be applied on a large scale to soften panic and economic burden through guidance for isolation strategies.

scholarly journals An Artificial Intelligence-Assisted Portable Low-Cost Device for the Rapid Detection of SARS-CoV-2

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2065
Author(s):  
Mukunthan Tharmakulasingam ◽  
Nouman S. Chaudhry ◽  
Manoharanehru Branavan ◽  
Wamadeva Balachandran ◽  
Aurore C. Poirier ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Rapid Detection ◽  
Template Matching ◽  
Low Cost ◽  
Lamp Assay ◽  
High Sensitivity ◽  
High Specificity ◽  
Cost Effective ◽  
Mobile App ◽  
Run Time

An artificial intelligence-assisted low-cost portable device for the rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is presented here. This standalone temperature-controlled device houses tubes designed for conducting reverse transcription loop-mediated isothermal amplification (RT-LAMP) assays. Moreover, the device utilises tubes illuminated by LEDs, an in-built camera, and a small onboard computer with automated image acquisition and processing algorithms. This intelligent device significantly reduces the normal assay run time and removes the subjectivity associated with operator interpretation of colourimetric RT-LAMP results. To further improve this device’s usability, a mobile app has been integrated into the system to control the LAMP assay environment and to visually display the assay results by connecting the device to a smartphone via Bluetooth. This study was undertaken using ~5000 images produced from the ~200 LAMP amplification assays using the prototype device. Synthetic RNA and a small panel of positive and negative SARS-CoV-2 patient samples were assayed for this study. State-of-the-art image processing and artificial intelligence algorithms were applied to these images to analyse them and to select the most efficient algorithm. The template matching algorithm for image extraction and MobileNet CNN architecture for classification results provided 98.0% accuracy with an average run time of 20 min to confirm the endpoint result. Two working points were chosen based on the best compromise between sensitivity and specificity. The high sensitivity point has a sensitivity value of 99.12% and specificity value of 70.8%, while at the high specificity point, the sensitivity is 96.05% and specificity 93.59%. Furthermore, this device provides an efficient and cost-effective platform for non-health professionals to detect not only SARS-CoV-2 but also other pathogens in resource-limited laboratories, factories, airports, schools, universities, and homes.

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