scholarly journals Towards Easy-to-Use Bacteria Sensing: Modeling and Simulation of a New Environmental Impedimetric Biosensor in Fluids

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1487
Author(s):  
Christian Pfeffer ◽  
Yue Liang ◽  
Helmut Grothe ◽  
Bernhard Wolf ◽  
Ralf Brederlow
Keyword(s):  
Electric Field ◽  
Pathogenic Bacteria ◽  
Dynamic Range ◽  
Excitation Amplitude ◽  
Mathematical Concept ◽  
Detection Methods ◽  
Spatial Dimensions ◽  
Sensor Models ◽  
Impedimetric Biosensor ◽  
Pathogenic Bacteria Detection

Conventional pathogenic bacteria-detection methods are lab-bound, time-consuming and need trained personnel. Microelectrodes can be used to recognize harmful microorganisms by dielectric impedance spectroscopy. However, crucial for this spectroscopy method are the spatial dimensions and layout of the electrodes, as the corresponding distribution of the electric field defines the sensor system parameters such as sensitivity, SNR, and dynamic range. Therefore, a variety of sensor models are created and evaluated. FEM simulations in 2D and 3D are conducted for this impedimetric sensor. The authors tested differently shaped structures, verified the linear influence of the excitation amplitude and developed a mathematical concept for a quality factor that practically allows us to distinguish arbitrary sensor designs and layouts. The effect of guard electrodes blocking outer influences on the electric field are investigated, and essential configurations are explored. The results lead to optimized electronic sensors in terms of geometrical dimensions. Possible material choices for real sensors as well as design and layout recommendations are presented.

scholarly journals Detectivity optimization to detect of ultraweak light fluxes with an EM-CCD as binary photon counter array

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ibtissame Khaoua ◽  
Guillaume Graciani ◽  
Andrey Kim ◽  
François Amblard
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Detection Methods ◽  
Strong Nonlinearity ◽  
Wide Range ◽  
Depth Analysis ◽  
Spatially Extended ◽  
Extended Sources ◽  
Photon Counting Mode

AbstractFor a wide range of purposes, one faces the challenge to detect light from extremely faint and spatially extended sources. In such cases, detector noises dominate over the photon noise of the source, and quantum detectors in photon counting mode are generally the best option. Here, we combine a statistical model with an in-depth analysis of detector noises and calibration experiments, and we show that visible light can be detected with an electron-multiplying charge-coupled devices (EM-CCD) with a signal-to-noise ratio (SNR) of 3 for fluxes less than $$30\,{\text{photon}}\,{\text{s}}^{ - 1} \,{\text{cm}}^{ - 2}$$ 30 photon s - 1 cm - 2 . For green photons, this corresponds to 12 aW $${\text{cm}}^{ - 2}$$ cm - 2 ≈ $$9{ } \times 10^{ - 11}$$ 9 × 10 - 11 lux, i.e. 15 orders of magnitude less than typical daylight. The strong nonlinearity of the SNR with the sampling time leads to a dynamic range of detection of 4 orders of magnitude. To detect possibly varying light fluxes, we operate in conditions of maximal detectivity $${\mathcal{D}}$$ D rather than maximal SNR. Given the quantum efficiency $$QE\left( \lambda \right)$$ Q E λ of the detector, we find $${ \mathcal{D}} = 0.015\,{\text{photon}}^{ - 1} \,{\text{s}}^{1/2} \,{\text{cm}}$$ D = 0.015 photon - 1 s 1 / 2 cm , and a non-negligible sensitivity to blackbody radiation for T > 50 °C. This work should help design highly sensitive luminescence detection methods and develop experiments to explore dynamic phenomena involving ultra-weak luminescence in biology, chemistry, and material sciences.

AN OCEAN BOTTOM, D COMPONENT MAGNETOMETER

Geophysics ◽  
1967 ◽  
Vol 32 (6) ◽  
pp. 978-987 ◽  
Author(s):  
J. H. Filloux
Keyword(s):  
Electric Field ◽  
Dynamic Range ◽  
North Pacific Ocean ◽  
Mooring Line ◽  
Ocean Bottom ◽  
Magnetic Fluctuations ◽  
Sea Floor ◽  
The North ◽  
Low Profile ◽  
Optical Lever

The distribution of electric conductivity in the crustal and upper mantle materials beneath the ocean may be estimated from measurements of the relationship between the magnetic fluctuations and the induced electric field at the ocean bottom. Techniques for the measurement of the electric field have been available for a few years. The horizontal magnetic fluctuations to the magnetic east, usually called D, can be recorded with a simple instrument placed on the sea floor at any depth. This instrument uses a magnet pair which orients itself among the main horizontal field H. The coupling of the magnets to the mirror of a sensitive optical lever is delayed until the instrument has reached the bottom. There is no need to perform any orientation in situ. The instrument resolves 1 γ or less and has a dynamic range of at least 2500 γ. It is capable of recording for approximately 40 days at the rate of 30 readings per hour on self‐contained dry cells. It is lowered to the sea floor and recovered by means of a mooring line connected to a surface float. The low‐profile supporting tripod is effectively decoupled from the mooring tackle as evidenced by the lack of motion of the magnetometer during 26 days of recording. A sample of the observed fluctuations on the floor of the North Pacific Ocean, 600 km offshore, is given.

scholarly journals Recent Advances in Electrochemical and Optical Biosensors Designed for Detection of Interleukin 6

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 646 ◽  
Author(s):  
Munezza Ata Khan ◽  
Mohammad Mujahid
Keyword(s):  
Interleukin 6 ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
High Specificity ◽  
Detection Methods ◽  
Optical Biosensors ◽  
Integrated Electronics ◽  
Life Threatening ◽  
And Performance ◽  
Commercial Applications

Interleukin 6 (IL-6), being a major component of homeostasis, immunomodulation, and hematopoiesis, manifests multiple pathological conditions when upregulated in response to viral, microbial, carcinogenic, or autoimmune stimuli. High fidelity immunosensors offer real-time monitoring of IL-6 and facilitate early prognosis of life-threatening diseases. Different approaches to augment robustness and enhance overall performance of biosensors have been demonstrated over the past few years. Electrochemical- and fluorescence-based detection methods with integrated electronics have been subjects of intensive research due to their ability to offer a better signal-to-noise ratio, high specificity, ultra-sensitivity, and wide dynamic range. In this review, the pleiotropic role of IL-6 and its clinical significance is discussed in detail, followed by detection schemes devised so far for their quantitative analysis. A critical review on underlying signal amplification strategies and performance of electrochemical and optical biosensors is presented. In conclusion, we discuss the reliability and feasibility of the proposed detection technologies for commercial applications.

scholarly journals Recent Advances in Electrochemiluminescence Sensors for Pathogenic Bacteria Detection

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 532 ◽  
Author(s):  
Jinjin Shen ◽  
Ting Zhou ◽  
Ru Huang
Keyword(s):  
Pathogenic Bacteria ◽  
Early Stage ◽  
Point Of Care ◽  
Health And Safety ◽  
High Sensitivity ◽  
Economic Losses ◽  
Bacteria Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Recent Advances ◽  
Pathogenic Bacteria Detection

Pathogenic bacterial contamination greatly threats human health and safety. Rapidly biosensing pathogens in the early stage of infection would be helpful to choose the correct drug treatment, prevent transmission of pathogens, as well as decrease mortality and economic losses. Traditional techniques, such as polymerase chain reaction and enzyme-linked immunosorbent assay, are accurate and effective, but are greatly limited because they are complex and time-consuming. Electrochemiluminescence (ECL) biosensors combine the advantages of both electrochemical and photoluminescence analysis and are suitable for high sensitivity and simple pathogenic bacteria detection. In this review, we summarize recent advances in ECL sensors for pathogenic bacteria detection and highlight the development of paper-based ECL platforms in point of care diagnosis of pathogens.

RF MEMS-Based Biosensor for Pathogenic Bacteria Detection

2013 ◽  
Vol 3 (3) ◽  
pp. 321-328 ◽  
Author(s):  
Chithra ◽  
Pallavi S. ◽  
A. Amalin Prince
Keyword(s):  
Pathogenic Bacteria ◽  
Rf Mems ◽  
Bacteria Detection ◽  
Pathogenic Bacteria Detection

scholarly journals Spatial dimensions of the electron diffusion region in anti-parallel magnetic reconnection

2016 ◽  
Vol 34 (3) ◽  
pp. 357-367 ◽  
Author(s):  
Takuma Nakamura ◽  
Rumi Nakamura ◽  
Hiroshi Haseagwa
Keyword(s):  
Electric Field ◽  
Magnetic Reconnection ◽  
Real Space ◽  
Diffusion Region ◽  
Electron Mass ◽  
Plasma Parameters ◽  
Electron Diffusion ◽  
Background Density ◽  
Spatial Dimensions ◽  
Inner Region

Abstract. Spatial dimensions of the detailed structures of the electron diffusion region in anti-parallel magnetic reconnection were analyzed based on two-dimensional fully kinetic particle-in-cell simulations. The electron diffusion region in this study is defined as the region where the positive reconnection electric field is sustained by the electron inertial and non-gyrotropic pressure components. Past kinetic studies demonstrated that the dimensions of the whole electron diffusion region and the inner non-gyrotropic region are scaled by the electron inertial length de and the width of the electron meandering motion, respectively. In this study, we successfully obtained more precise scalings of the dimensions of these two regions than the previous studies by performing simulations with sufficiently small grid spacing (1∕16–1∕8 de) and a sufficient number of particles (800 particles cell−1 on average) under different conditions changing the ion-to-electron mass ratio, the background density and the electron βe (temperature). The obtained scalings are adequately supported by some theories considering spatial variations of field and plasma parameters within the diffusion region. In the reconnection inflow direction, the dimensions of both regions are proportional to de based on the background density. Both dimensions also depend on βe based on the background values, but the dependence in the inner region ( ∼ 0.375th power) is larger than the whole region (0.125th power) reflecting the orbits of meandering and accelerated electrons within the inner region. In the outflow direction, almost only the non-gyrotropic component sustains the positive reconnection electric field. The dimension of this single-scale diffusion region is proportional to the ion-electron hybrid inertial length (dide)1∕2 based on the background density and weakly depends on the background βe with the 0.25th power. These firm scalings allow us to predict observable dimensions in real space which are indeed in reasonable agreement with past in situ spacecraft observations in the Earth's magnetotail and have important implications for future observations with higher resolutions such as the NASA Magnetospheric Multiscale (MMS) mission.

Real-Time Nucleic Acid–Based Detection Methods for Pathogenic Bacteria in Food

2004 ◽  
Vol 67 (4) ◽  
pp. 823-832 ◽  
Author(s):  
JOHN L. McKILLIP ◽  
MARYANNE DRAKE
Keyword(s):  
Nucleic Acid ◽  
Real Time ◽  
Real Time Pcr ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Pathogen Detection ◽  
Food Microbiology ◽  
Detection Methods ◽  
Target Sequence ◽  
Bacterial Enumeration

Quality assurance in the food industry in recent years has involved the acceptance and implementation of a variety of nucleic acid–based methods for rapid and sensitive detection of food-associated pathogenic bacteria. Techniques such as polymerase chain reaction have greatly expedited the process of pathogen detection and have in some cases replaced traditional methods for bacterial enumeration in food. Conventional PCR, albeit sensitive and specific under optimized conditions, obligates the user to employ agarose gel electrophoresis as the means for endpoint analysis following sample processing. For the last few years, a variety of real-time PCR chemistries and detection instruments have appeared on the market, and many of these lend themselves to applications in food microbiology. These approaches afford a user the ability to amplify DNA or RNA, as well as detect and confirm target sequence identity in a closed-tube format with the use of a variety of fluorophores, labeled probes, or both, without the need to run gels. Such real-time chemistries also offer greater sensitivity than traditional gel visualization and can be semiquantitative and multiplexed depending on the specific experimental objectives. This review emphasizes the current systems available for real-time PCR–based pathogen detection, the basic mechanisms and requirements for each, and the prospects for development over the next few years in the food industry.

AOTF hyperspectral microscopic imaging for foodborne pathogenic bacteria detection

2011 ◽  
Author(s):  
Bosoon Park ◽  
Sangdae Lee ◽  
Seung-Chul Yoon ◽  
Jaya Sundaram ◽  
William R. Windham ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Bacteria Detection ◽  
Microscopic Imaging ◽  
Foodborne Pathogenic Bacteria ◽  
Pathogenic Bacteria Detection
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