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Biosensors

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https://www.readbyqxmd.com/read/28934106/biosensor-technology-reveals-the-disruption-of-the-endothelial-barrier-function-and-the-subsequent-death-of-blood-brain-barrier-endothelial-cells-to-sodium-azide-and-its-gaseous-products
#1
Dan T Kho, Rebecca H Johnson, Simon J O'Carroll, Catherine E Angel, E Scott Graham
Herein we demonstrate the sensitive nature of human blood-brain barrier (BBB) endothelial cells to sodium azide and its gaseous product. Sodium azide is known to be acutely cytotoxic at low millimolar concentrations, hence its use as a biological preservative (e.g., in antibodies). Loss of barrier integrity was noticed in experiments using Electric Cell-substrate Impedance Sensing (ECIS) biosensor technology, to measure endothelial barrier integrity continuously in real-time. Initially the effect of sodium azide was observed as an artefact where it was present in antibodies being employed in neutralisation experiments...
September 21, 2017: Biosensors
https://www.readbyqxmd.com/read/28930184/use-of-wavelet-transform-to-detect-compensated-and-decompensated-stages-in-the-congestive-heart-failure-patient
#2
Pratibha Sharma, Kimberly Newman, Carlin S Long, A J Gasiewski, Frank Barnes
This research work is aimed at improving health care, reducing cost, and the occurrence of emergency hospitalization in patients with Congestive Heart Failure (CHF) by analyzing heart and lung sounds to distinguish between the compensated and decompensated states. Compensated state defines stable state of the patient but with lack of retention of fluids in lungs, whereas decompensated state leads to unstable state of the patient with lots of fluid retention in the lungs, where the patient needs medication. Acoustic signals from the heart and the lung were analyzed using wavelet transforms to measure changes in the CHF patient's status from the decompensated to compensated and vice versa...
September 20, 2017: Biosensors
https://www.readbyqxmd.com/read/28930183/substituting-sodium-hydrosulfite-with-sodium-metabisulfite-improves-long-term-stability-of-a-distributable-paper-based-test-kit-for-point-of-care-screening-for-sickle-cell-anemia
#3
Kian Torabian, Dalia Lezzar, Nathaniel Z Piety, Alex George, Sergey S Shevkoplyas
Sickle cell anemia (SCA) is a genetic blood disorder that is particularly lethal in early childhood. Universal newborn screening programs and subsequent early treatment are known to drastically reduce under-five SCA mortality. However, in resource-limited settings, cost and infrastructure constraints limit the effectiveness of laboratory-based SCA screening programs. To address this limitation our laboratory previously developed a low-cost, equipment-free, point-of-care, paper-based SCA test. Here, we improved the stability and performance of the test by replacing sodium hydrosulfite (HS), a key reducing agent in the hemoglobin solubility buffer which is not stable in aqueous solutions, with sodium metabisulfite (MS)...
September 20, 2017: Biosensors
https://www.readbyqxmd.com/read/28927005/mediatorless-impedance-studies-with-titanium-dioxide-conjugated-gold-nanoparticles-for-hydrogen-peroxide-detection
#4
Nur Hamidah Abdul Halim, Yook Heng Lee, Radha Swathe Priya Malon Marugan, Uda Hashim
An impedimetric-based biosensor constructed using gold nanoparticles (AuNP) entrapped within titanium dioxide (TiO₂) particles for hydrogen peroxide (H₂O₂) detection is the main feature of this research. The matrix of the biosensor employed the surface of TiO₂, which was previously modified with an amine terminal group using 3-Aminopropyltriethoxysilane (APTS) at a low temperature to create a ready to immobilise surface for the biosensor application. Hemoglobin (Hb), which exhibits peroxidase-like activity, was used as the bioreceptor in the biosensor to detect H₂O₂ in solution...
September 18, 2017: Biosensors
https://www.readbyqxmd.com/read/28906469/silicon-integrated-dual-mode-interferometer-with-differential-outputs
#5
Niklas Hoppe, Pascal Scheck, Rami Sweidan, Philipp Diersing, Lotte Rathgeber, Wolfgang Vogel, Benjamin Riegger, Alexander Southan, Manfred Berroth
The dual-mode interferometer (DMI) is an attractive alternative to Mach-Zehnder interferometers for sensor purposes, achieving sensitivities to refractive index changes close to state-of-the-art. Modern designs on silicon-on-insulator (SOI) platforms offer thermally stable and compact devices with insertion losses of less than 1 dB and high extinction ratios. Compact arrays of multiple DMIs in parallel are easy to fabricate due to the simple structure of the DMI. In this work, the principle of operation of an integrated DMI with differential outputs is presented which allows the unambiguous phase shift detection with a single wavelength measurement, rather than using a wavelength sweep and evaluating the optical output power spectrum...
September 14, 2017: Biosensors
https://www.readbyqxmd.com/read/28878194/a-rationally-designed-reversible-turn-off-sensor-for-glutathione
#6
Sabrina Heng, Xiaozhou Zhang, Jinxin Pei, Andrew D Abell
γ-Glutamyl-cysteinyl-glycine (GSH) plays a critical role in maintaining redox homeostasis in biological systems and a decrease in its cellular levels is associated with diseases. Existing fluorescence-based chemosensors for GSH acts as irreversible reaction-based probes that exhibit a maximum fluorescence ('turn-on') once the reaction is complete, regardless of the actual concentration of GSH. A reversible, reaction-based 'turn-off' probe ( 1 ) is reported here to sense the decreasing levels of GSH, a situation known to occur at the onset of various diseases...
September 6, 2017: Biosensors
https://www.readbyqxmd.com/read/28858219/a-novel-impedance-biosensor-for-measurement-of-trans-epithelial-resistance-in-cells-cultured-on-nanofiber-scaffolds
#7
Robert A Schramm, Matthew H Koslow, Deirdre A Nelson, Melinda Larsen, James Castracane
Nanofibrous scaffolds provide high surface area for cell attachment, and resemble the structure of the collagen fibers which naturally occur in the basement membrane and extracellular matrix. A label free and non-destructive method of assessing the interaction of cell tissue and scaffolds aids in the ability to discern the effective quality and magnitude of any scaffold modifications. Impedance cell spectroscopy is a biosensing method that employs a functional approach to assessing the cell monolayer. The electrical impedance barrier function of a cell monolayer represents the level of restriction to diffusion of charged species between all adjacent cells across an entire contiguous cellular monolayer...
August 31, 2017: Biosensors
https://www.readbyqxmd.com/read/28820461/thermal-response-analysis-of-phospholipid-bilayers-using-ellipsometric-techniques
#8
Carmen M González-Henríquez, Vanessa A Villegas-Opazo, Dallits H Sagredo-Oyarce, Mauricio A Sarabia-Vallejos, Claudio A Terraza
Biomimetic planar artificial membranes have been widely studied due to their multiple applications in several research fields. Their humectation and thermal response are crucial for reaching stability; these characteristics are related to the molecular organization inside the bilayer, which is affected by the aliphatic chain length, saturations, and molecule polarity, among others. Bilayer stability becomes a fundamental factor when technological devices are developed-like biosensors-based on those systems...
August 18, 2017: Biosensors
https://www.readbyqxmd.com/read/28817097/bloch-surface-waves-biosensors-for-high-sensitivity-detection-of-soluble-erbb2-in-a-complex-biological-environment
#9
Alberto Sinibaldi, Camilla Sampaoli, Norbert Danz, Peter Munzert, Frank Sonntag, Fabio Centola, Agostino Occhicone, Elisa Tremante, Patrizio Giacomini, Francesco Michelotti
We report on the use of one-dimensional photonic crystals to detect clinically relevant concentrations of the cancer biomarker ERBB2 in cell lysates. Overexpression of the ERBB2 protein is associated with aggressive breast cancer subtypes. To detect soluble ERBB2, we developed an optical set-up which operates in both label-free and fluorescence modes. The detection approach makes use of a sandwich assay, in which the one-dimensional photonic crystals sustaining Bloch surface waves are modified with monoclonal antibodies, in order to guarantee high specificity during the biological recognition...
August 17, 2017: Biosensors
https://www.readbyqxmd.com/read/28783115/a-novel-surface-plasmon-resonance-biosensor-for-the-rapid-detection-of-botulinum-neurotoxins
#10
Kruti Patel, Shmuel Halevi, Paul Melman, John Schwartz, Shuowei Cai, Bal Ram Singh
Botulinum neurotoxins (BoNTs) are Category A agents on the NIAID (National Institute of Allergy and Infectious Diseases) priority pathogen list owing to their extreme toxicity and the relative ease of production. These deadly toxins, in minute quantities (estimated human i.v. lethal dose LD50 of 1-2 ng/kg body weight), cause fatal flaccid paralysis by blocking neurotransmitter release. The current gold standard detection method, the mouse-bioassay, often takes days to confirm botulism. Furthermore, there are no effective antidotes known to reverse the symptoms of botulism, and as a result, patients with severe botulism often require meticulous care during the prolonged paralytic illness...
August 7, 2017: Biosensors
https://www.readbyqxmd.com/read/28783063/an-affordable-microsphere-based-device-for-visual-assessment-of-water-quality
#11
Azra Rajwani, Brendon Restall, Nathan J Muller, Scott Roebuck, Stephanie M Willerth
This work developed a prototype of an affordable, long-term water quality detection device that provides a visual readout upon detecting bacterial contamination. This device prototype consists of: (1) enzyme-releasing microspheres that lyse bacteria present in a sample, (2) microspheres that release probes that bind the DNA of the lysed bacteria, and (3) a detector region consisting of gold nanoparticles. The probes bind bacterial DNA, forming complexes. These complexes induce aggregation of the gold nanoparticles located in the detector region...
August 5, 2017: Biosensors
https://www.readbyqxmd.com/read/28771209/point-of-care-testing-in-acute-stroke-management-an-unmet-need-ripe-for-technological-harvest
#12
REVIEW
Dorin Harpaz, Evgeni Eltzov, Raymond C S Seet, Robert S Marks, Alfred I Y Tok
Stroke, the second highest leading cause of death, is caused by an abrupt interruption of blood to the brain. Supply of blood needs to be promptly restored to salvage brain tissues from irreversible neuronal death. Existing assessment of stroke patients is based largely on detailed clinical evaluation that is complemented by neuroimaging methods. However, emerging data point to the potential use of blood-derived biomarkers in aiding clinical decision-making especially in the diagnosis of ischemic stroke, triaging patients for acute reperfusion therapies, and in informing stroke mechanisms and prognosis...
August 3, 2017: Biosensors
https://www.readbyqxmd.com/read/28726727/in-vitro-quantified-determination-of-%C3%AE-amyloid-42-peptides-a-biomarker-of-neuro-degenerative-disorders-in-pbs-and-human-serum-using-a-simple-cost-effective-thin-gold-film-biosensor
#13
Yifan Dai, Alireza Molazemhosseini, Chung Chiun Liu
A simple in vitro biosensor for the detection of β-amyloid 42 in phosphate-buffered saline (PBS) and undiluted human serum was fabricated and tested based on our platform sensor technology. The bio-recognition mechanism of this biosensor was based on the effect of the interaction between antibody and antigen of β-amyloid 42 to the redox couple probe of K₄Fe(CN)₆ and K₃Fe(CN)₆. Differential pulse voltammetry (DPV) served as the transduction mechanism measuring the current output derived from the redox coupling reaction...
July 20, 2017: Biosensors
https://www.readbyqxmd.com/read/28718841/development-of-an-immunosensor-for-pfhrp-2-as-a-biomarker-for-malaria-detection
#14
Aver Hemben, Jon Ashley, Ibtisam E Tothill
Plasmodium falciparum histidine-rich protein 2 (PfHRP 2) was selected in this work as the biomarker for the detection and diagnosis of malaria. An enzyme-linked immunosorbent assay (ELISA) was first developed to evaluate the immunoreagent's suitability for the sensor's development. A gold-based sensor with an integrated counter and an Ag/AgCl reference electrode was first selected and characterised and then used to develop the immunosensor for PfHRP 2, which enables a low cost, easy to use, and sensitive biosensor for malaria diagnosis...
July 18, 2017: Biosensors
https://www.readbyqxmd.com/read/28704926/a-label-free-and-ultrasensitive-immunosensor-for-detection-of-human-chorionic-gonadotrophin-based-on-graphene-fets
#15
Kamrul Islam, Ahmed Suhail, Genhua Pan
We report on a label-free immunosensor based on graphene field effect transistors (G-FETs) for the ultrasensitive detection of Human Chorionic Gonadotrophin (hCG), as an indicator of pregnancy and related disorders, such as actopic pregnancy, choriocarcinoma and orchic teratoma. Pyrene based bioactive ester was non-covalently anchored onto the graphene channel in order to retain the sp² lattice. The G-FET transfer characteristics showed repeatable and reliable responses in all surface modifying steps using a direct current (DC) readout system...
July 12, 2017: Biosensors
https://www.readbyqxmd.com/read/28678160/lipid-bilayer-membrane-in-a-silicon-based-micron-sized-cavity-accessed-by-atomic-force-microscopy-and-electrochemical-impedance-spectroscopy
#16
Muhammad Shuja Khan, Noura Sayed Dosoky, Darayas Patel, Jeffrey Weimer, John Dalton Williams
Supported lipid bilayers (SLBs) are widely used in biophysical research to probe the functionality of biological membranes and to provide diagnoses in high throughput drug screening. Formation of SLBs at below phase transition temperature (Tm) has applications in nano-medicine research where low temperature profiles are required. Herein, we report the successful production of SLBs at above-as well as below-the Tm of the lipids in an anisotropically etched, silicon-based micro-cavity. The Si-based cavity walls exhibit controlled temperature which assist in the quick and stable formation of lipid bilayer membranes...
July 5, 2017: Biosensors
https://www.readbyqxmd.com/read/28677660/detection-of-lipid-and-amphiphilic-biomarkers-for-disease-diagnostics
#17
REVIEW
Jessica Z Kubicek-Sutherland, Dung M Vu, Heather M Mendez, Shailja Jakhar, Harshini Mukundan
Rapid diagnosis is crucial to effectively treating any disease. Biological markers, or biomarkers, have been widely used to diagnose a variety of infectious and non-infectious diseases. The detection of biomarkers in patient samples can also provide valuable information regarding progression and prognosis. Interestingly, many such biomarkers are composed of lipids, and are amphiphilic in biochemistry, which leads them to be often sequestered by host carriers. Such sequestration enhances the difficulty of developing sensitive and accurate sensors for these targets...
July 4, 2017: Biosensors
https://www.readbyqxmd.com/read/28644395/optical-tracking-and-digital-quantification-of-beating-behavior-in-bioengineered-human-cardiac-organoids
#18
Mahesh Devarasetty, Steven Forsythe, Thomas D Shupe, Shay Soker, Colin E Bishop, Anthony Atala, Aleksander Skardal
Organoid and organ-on-a-chip technologies are rapidly advancing towards deployment for drug and toxicology screening applications. Liver and cardiac toxicities account for the majority of drug candidate failures in human trials. Liver toxicity generally produces liver cell death, while cardiac toxicity causes adverse changes in heart beat kinetics. In traditional 2D cultures, beating kinetics can be measured by electrode arrays, but in some 3D constructs, quantifying beating kinetics can be more challenging...
June 23, 2017: Biosensors
https://www.readbyqxmd.com/read/28635665/towards-a-uniform-metrological-assessment-of-grating-based-optical-fiber-sensors-from-refractometers-to-biosensors
#19
REVIEW
Francesco Chiavaioli, Carlos A J Gouveia, Pedro A S Jorge, Francesco Baldini
A metrological assessment of grating-based optical fiber sensors is proposed with the aim of providing an objective evaluation of the performance of this sensor category. Attention was focused on the most common parameters, used to describe the performance of both optical refractometers and biosensors, which encompassed sensitivity, with a distinction between volume or bulk sensitivity and surface sensitivity, resolution, response time, limit of detection, specificity (or selectivity), reusability (or regenerability) and some other parameters of generic interest, such as measurement uncertainty, accuracy, precision, stability, drift, repeatability and reproducibility...
June 21, 2017: Biosensors
https://www.readbyqxmd.com/read/28635643/a-multi-wavelength-opto-electronic-patch-sensor-to-effectively-detect-physiological-changes-against-human-skin-types
#20
Liangwen Yan, Sijung Hu, Abdullah Alzahrani, Samah Alharbi, Panagiotis Blanos
Different skin pigments among various ethnic group people have an impact on spectrometric illumination on skin surface. To effectively capture photoplethysmographic (PPG) signals, a multi-wavelength opto-electronic patch sensor (OEPS) together with a schematic architecture of electronics were developed to overcome the drawback of present PPG sensor. To perform a better in vivo physiological measurement against skin pigments, optimal illuminations in OEPS, whose wavelength is compatible with a specific skin type, were optimized to capture a reliable physiological sign of heart rate (HR)...
June 21, 2017: Biosensors
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