scholarly journals Biosensors Based on Mechanical and Electrical Detection Techniques

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5605
Author(s):  
Thomas Chalklen ◽  
Qingshen Jing ◽  
Sohini Kar-Narayan
Keyword(s):  
Electrochemical Techniques ◽  
Chemical Change ◽  
Medical Diagnostics ◽  
Electrical Signal ◽  
Optical Methods ◽  
Electrical Detection ◽  
Detection Techniques ◽  
Challenges And Opportunities ◽  
Biological Recognition ◽  
Electrical Biosensors

Biosensors are powerful analytical tools for biology and biomedicine, with applications ranging from drug discovery to medical diagnostics, food safety, and agricultural and environmental monitoring. Typically, biological recognition receptors, such as enzymes, antibodies, and nucleic acids, are immobilized on a surface, and used to interact with one or more specific analytes to produce a physical or chemical change, which can be captured and converted to an optical or electrical signal by a transducer. However, many existing biosensing methods rely on chemical, electrochemical and optical methods of identification and detection of specific targets, and are often: complex, expensive, time consuming, suffer from a lack of portability, or may require centralised testing by qualified personnel. Given the general dependence of most optical and electrochemical techniques on labelling molecules, this review will instead focus on mechanical and electrical detection techniques that can provide information on a broad range of species without the requirement of labelling. These techniques are often able to provide data in real time, with good temporal sensitivity. This review will cover the advances in the development of mechanical and electrical biosensors, highlighting the challenges and opportunities therein.

scholarly journals Nanozymes for Environmental Pollutant Monitoring and Remediation

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 408
Author(s):  
Elicia L. S. Wong ◽  
Khuong Q. Vuong ◽  
Edith Chow
Keyword(s):  
Real Time ◽  
Organic Pollutants ◽  
Architectural Design ◽  
Electrochemical Techniques ◽  
Environmental Pollutant ◽  
Field Application ◽  
Optical Methods ◽  
Enzyme Mimicking ◽  
Active Metal ◽  
Recent Developments

Nanozymes are advanced nanomaterials which mimic natural enzymes by exhibiting enzyme-like properties. As nanozymes offer better structural stability over their respective natural enzymes, they are ideal candidates for real-time and/or remote environmental pollutant monitoring and remediation. In this review, we classify nanozymes into four types depending on their enzyme-mimicking behaviour (active metal centre mimic, functional mimic, nanocomposite or 3D structural mimic) and offer mechanistic insights into the nature of their catalytic activity. Following this, we discuss the current environmental translation of nanozymes into a powerful sensing or remediation tool through inventive nano-architectural design of nanozymes and their transduction methodologies. Here, we focus on recent developments in nanozymes for the detection of heavy metal ions, pesticides and other organic pollutants, emphasising optical methods and a few electrochemical techniques. Strategies to remediate persistent organic pollutants such as pesticides, phenols, antibiotics and textile dyes are included. We conclude with a discussion on the practical deployment of these nanozymes in terms of their effectiveness, reusability, real-time in-field application, commercial production and regulatory considerations.

scholarly journals Photonics of human saliva: potential optical methods for the screening of abnormal health conditions and infections

2021 ◽  
Author(s):  
Jijo Lukose ◽  
Sanoop Pavithran M. ◽  
Mithun N. ◽  
Ajaya Kumar Barik ◽  
Keerthilatha M. Pai ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Viral Infections ◽  
Clinical Specimen ◽  
Human Saliva ◽  
Medical Diagnostics ◽  
Optical Methods ◽  
Health Conditions ◽  
Personal Health ◽  
Fast Detection ◽  
Non Invasive

AbstractHuman saliva can be treated as a pool of biological markers able to reflect on the state of personal health. Recent years have witnessed an increase in the use of optical devices for the analysis of body fluids. Several groups have carried out studies investigating the potential of saliva as a non-invasive and reliable clinical specimen for use in medical diagnostics. This brief review aims to highlight the optical technologies, mainly surface plasmon resonance (SPR), Raman, and Fourier transform infrared (FTIR) spectroscopy, which are being used for the probing of saliva for diverse biomedical applications. Advances in bio photonics offer the promise of unambiguous, objective and fast detection of abnormal health conditions and viral infections (such as COVID-19) from the analysis of saliva.

Partial Discharge Detection Using Acoustic and Optical Methods in High Voltage Power Equipments: A Review

2013 ◽  
Vol 845 ◽  
pp. 283-286 ◽  
Author(s):  
Malik Abdul Razzaq Al Saedi ◽  
Mohd Muhridza Yaacob
Keyword(s):  
Acoustic Emission ◽  
High Voltage ◽  
Power Transformer ◽  
Partial Discharge ◽  
Optical Detection ◽  
Detection Threshold ◽  
Optical Methods ◽  
Detection Methods ◽  
Detection Techniques ◽  
Advantages And Disadvantages

There is a high risk of insulation system dielectric instability when partial discharge (PD) occurs. Therefore, measurement and monitoring of PD is an important preventive tool to safeguard high-voltage equipment from wanton damage. PD can be detected using optical method to increase the detection threshold and to improve the performance of on-line measurement of PD in noise environment. The PD emitted energy as acoustic emission. We can use this emitted energy to detect PD signal. The best method to detect PD in power transformer is by using acoustic emission. Optical sensor has some advantages such as; high sensitivity, more accuracy small size. Furthermore, in on-site measurements and laboratory experiments, it isoptical methodthat gives very moderate signal attenuations. This paper reviews the available PD detection methods (involving high voltage equipment) such as; acoustic detection and optical detection. The advantages and disadvantages of each method have been explored and compared. The review suggests that optical detection techniques provide many advantages from the consideration of accuracy and suitability for the applications when compared to other techniques.

Detecting explosives and chemical weapons: a review of recent developments

Sensor Review ◽  
2015 ◽  
Vol 35 (3) ◽  
pp. 237-243 ◽  
Author(s):  
Robert Bogue
Keyword(s):  
New Technologies ◽  
Electrochemical Techniques ◽  
Health And Safety ◽  
Chemical Warfare Agents ◽  
Chemical Warfare ◽  
Optical Methods ◽  
Chemical Weapons ◽  
Content Type ◽  
Recent Developments ◽  
Warfare Agents

Purpose – The purpose of this paper is to provide details of recent developments in sensors for detecting explosives and chemical warfare agents. Design/methodology/approach – Following an introduction, this paper first discusses a selection of new sensing techniques aimed at detecting explosives and explosive devices. It then considers new developments in sensors for detecting chemical warfare agents. Brief concluding comments are drawn. Findings – This paper shows that a diversity of sensor technologies is being investigated, including various advanced optical methods, nanomaterials, microelectromechanical system, electronic noses, biosensors and electrochemical techniques, several of which offer levels of sensitivity in the parts-per-trillion region. These not only have the potential to yield improved devices for detecting explosives and chemical weapons but may also play a role in health care, environmental monitoring, drug detection and industrial health and safety. Originality/value – In an era of escalating terrorism and military conflicts, this provides a timely review of new technologies for detecting explosives and chemical warfare agents.

scholarly journals Molecular Imprinted Polymer for a Purfication Device

2009 ◽  
Vol 3 (2) ◽  
Author(s):  
A. A. Bawazir ◽  
B. D. Moore ◽  
J. D. S. Gaylor
Keyword(s):  
Molecular Imprinting ◽  
Protein Extraction ◽  
Protein Denaturation ◽  
Solid Phase ◽  
Polymer Network ◽  
Medical Diagnostics ◽  
Aprotic Solvents ◽  
Imprinted Polymer ◽  
Nanostructured Particles ◽  
Biological Recognition

Molecular imprinting is a well established technology that mimics biological recognition systems using artificial materials. This involves synthesizing a nanostructured polymeric host in the presence of a target molecule to generate complementary binding sites that are selective for a molecule of interest. The technique offers a platform for developing simple and inexpensive systems with a vast array of applications such as; chromatography, separation, catalysts purification, solid phase extraction, biosensors, medical diagnostics and drug delivery. Elevated levels of some proteins in the blood can lead to a number of medical conditions. Incorporating these polymers into a device for blood purification to remove such molecules can be used as a means to combat these problems. Protein imprinting was studied from a novel perspective using protein coated micro crystals (PCMCs). PCMCs are nanostructured particles made via a rapid 1-step process developed by Moore et al. (2001). The use of a novel PCMCs strategy in molecular imprinting has allowed the retention of selected protein native conformation in organic media and the creation of access pores lined with nanocavities which facilitate protein extraction and re-introduction into the imprinted polymer. This technique has enabled us to overcome many of the challenges faced when using conventional imprinting methodology, such as protein insolubility in aprotic solvents, protein insolubility in aprotic solvents, protein denaturation and aggregation as a result of polymerization conditions and the permanent entrapment of the protein template in the cross linked polymer network.

Damage Evolution and Crack Growth in Nickel-Based Alloys during Ultrasonic Fatigue

2014 ◽  
Vol 783-786 ◽  
pp. 2410-2415 ◽  
Author(s):  
Martina Zimmermann ◽  
A. Kolyshkin ◽  
C. Stöcker ◽  
J.W. Jones ◽  
H.J. Christ
Keyword(s):  
Crack Initiation ◽  
Grain Boundaries ◽  
Crack Growth ◽  
Pure Nickel ◽  
Indirect Detection ◽  
Optical Methods ◽  
Coarse Grained ◽  
Detection Techniques ◽  
Nimonic 80A ◽  
Ultrasonic Fatigue

Experimental results on the fatigue damage of quasi defect-free materials in the VHCF range are presented. For nickel-based superalloys and pure nickel the likelihood of crack initiation at favorable grain morphologies is studied. Slip band and microcrack formation at the surface was observed even in run-out samples. Hence, microcracks were evaluated regarding their propagation capabilities according to grain orientation and barrier function of grain boundaries. In the VHCF regime crack initiation can shift from surface to subsurface, consequently early crack growth has to be studied by means of optical methods and indirect detection techniques or tomographic methods. In the study presented crack initiation and crack growth was monitored through optical observation and quasi 3-D observation by means of synchrotron radiation. For an as-received and a coarse-grained condition of pure nickel Ni201 fatigue crack growth in the VHCF regime occurs at deltaK as low as 3.54 MPam1/2 for a crack growth rate da/dN = 10E-12 m/cycle. The grain size had no effect on the threshold limit but crack growth retardation at grain boundaries and crack path deflection lead to lower crack growth rates for the coarse-grained condition In the nickel-based alloy Nimonic 80A the influence of microstructure on the intercrystalline crack initiation and propagation was confirmed. Here, the combination of the misorientation angle between two adjacent grains and the orientation of their boundary with respect to the external load defines the magnitude of stress concentration at grain boundaries.

scholarly journals A Performance Comparison and Enhancement of Animal Species Detection in Images with Various R-CNN Models

AI ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 552-577
Author(s):  
Mai Ibraheam ◽  
Kin Fun Li ◽  
Fayez Gebali ◽  
Leonard E. Sielecki
Keyword(s):  
Object Detection ◽  
Network Architecture ◽  
Animal Species ◽  
Detection System ◽  
Real Life ◽  
Medical Diagnostics ◽  
Performance Comparison ◽  
Species Detection ◽  
Detection Techniques ◽  
Wide Range

Object detection is one of the vital and challenging tasks of computer vision. It supports a wide range of applications in real life, such as surveillance, shipping, and medical diagnostics. Object detection techniques aim to detect objects of certain target classes in a given image and assign each object to a corresponding class label. These techniques proceed differently in network architecture, training strategy and optimization function. In this paper, we focus on animal species detection as an initial step to mitigate the negative impacts of wildlife–human and wildlife–vehicle encounters in remote wilderness regions and on highways. Our goal is to provide a summary of object detection techniques based on R-CNN models, and to enhance the performance of detecting animal species in accuracy and speed, by using four different R-CNN models and a deformable convolutional neural network. Each model is applied on three wildlife datasets, results are compared and analyzed by using four evaluation metrics. Based on the evaluation, an animal species detection system is proposed.

Biosensors

1989 ◽  
Vol 324 (1224) ◽  
pp. 487-496 ◽  
Keyword(s):  
Electron Transfer ◽  
Environmental Monitoring ◽  
Recent Progress ◽  
Biological Systems ◽  
Recognition System ◽  
Electrical Signal ◽  
Market Place ◽  
Effective Electron ◽  
Biological Recognition ◽  
New Generation

Biosensors are analytical devices that respond selectively to analytes in an appropriate sample and convert their concentration into an electrical signal via a combination of a biological recognition system and an electrochemical, optical or other transducer. Such devices will find application in medicine, agriculture, environmental monitoring and the bioprocessing industries. The last few years have seen great advances in the design of sensor architectures, the marriage of biological systems with monolithic silicon and optical technologies, the development of effective electron-transfer systems and the configuration of direct immunosensors. Recent progress in these areas has already led to the introduction of new-generation biosensors into the competitive diagnostics market place.

scholarly journals Nanomaterials-Based Electrochemical Sensors for In Vitro and In Vivo Analyses of Neurotransmitters

2018 ◽  
Vol 8 (9) ◽  
pp. 1504 ◽  
Author(s):  
Sharmila Durairaj ◽  
Boopathi Sidhureddy ◽  
Joseph Cirone ◽  
Aicheng Chen
Keyword(s):  
Electrochemical Sensors ◽  
Point Of Care ◽  
Electrochemical Techniques ◽  
High Sensitivity ◽  
Electrochemical Analysis ◽  
Detection Techniques ◽  
Efficient Detection ◽  
Sensitivity And Selectivity

Neurotransmitters are molecules that transfer chemical signals between neurons to convey messages for any action conducted by the nervous system. All neurotransmitters are medically important; the detection and analysis of these molecules play vital roles in the diagnosis and treatment of diseases. Among analytical strategies, electrochemical techniques have been identified as simple, inexpensive, and less time-consuming processes. Electrochemical analysis is based on the redox behaviors of neurotransmitters, as well as their metabolites. A variety of electrochemical techniques are available for the detection of biomolecules. However, the development of a sensing platform with high sensitivity and selectivity is challenging, and it has been found to be a bottleneck step in the analysis of neurotransmitters. Nanomaterials-based sensor platforms are fascinating for researchers because of their ability to perform the electrochemical analysis of neurotransmitters due to their improved detection efficacy, and they have been widely reported on for their sensitive detection of epinephrine, dopamine, serotonin, glutamate, acetylcholine, nitric oxide, and purines. The advancement of electroanalytical technologies and the innovation of functional nanomaterials have been assisting greatly in in vivo and in vitro analyses of neurotransmitters, especially for point-of-care clinical applications. In this review, firstly, we focus on the most commonly employed electrochemical analysis techniques, in conjunction with their working principles and abilities for the detection of neurotransmitters. Subsequently, we concentrate on the fabrication and development of nanomaterials-based electrochemical sensors and their advantages over other detection techniques. Finally, we address the challenges and the future outlook in the development of electrochemical sensors for the efficient detection of neurotransmitters.

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