scholarly journals Microfluidic-Based Electrochemical Immunosensing of Ferritin

Biosensors ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 91 ◽  
Author(s):  
Mayank Garg ◽  
Martin Christensen ◽  
Alexander Iles ◽  
Amit Sharma ◽  
Suman Singh ◽  
...  
Keyword(s):  
Electrochemical Detection ◽  
Point Of Care ◽  
Current Method ◽  
Fast Response ◽  
Flow Cell ◽  
The Body ◽  
Serum Samples ◽  
Functionalized Graphene Oxide ◽  
Microfluidic Flow ◽  
Sensitivity And Selectivity

Ferritin is a clinically important biomarker which reflects the state of iron in the body and is directly involved with anemia. Current methods available for ferritin estimation are generally not portable or they do not provide a fast response. To combat these issues, an attempt was made for lab-on-a-chip-based electrochemical detection of ferritin, developed with an integrated electrochemically active screen-printed electrode (SPE), combining nanotechnology, microfluidics, and electrochemistry. The SPE surface was modified with amine-functionalized graphene oxide to facilitate the binding of ferritin antibodies on the electrode surface. The functionalized SPE was embedded in the microfluidic flow cell with a simple magnetic clamping mechanism to allow continuous electrochemical detection of ferritin. Ferritin detection was accomplished via cyclic voltammetry with a dynamic linear range from 7.81 to 500 ng·mL−1 and an LOD of 0.413 ng·mL−1. The sensor performance was verified with spiked human serum samples. Furthermore, the sensor was validated by comparing its response with the response of the conventional ELISA method. The current method of microfluidic flow cell-based electrochemical ferritin detection demonstrated promising sensitivity and selectivity. This confirmed the plausibility of using the reported technique in point-of-care testing applications at a much faster rate than conventional techniques.

Ferromagnetic Resonance Biosensor for Homogeneous and Volumetric Detection of DNA

2017 ◽  
Author(s):  
Bo Tian ◽  
Peter Svedlindh ◽  
Mattias Strömberg ◽  
Erik Wetterskog
Keyword(s):  
Magnetic Nanoparticles ◽  
Ferromagnetic Resonance ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Rolling Circle Amplification ◽  
Resonance Field ◽  
Isothermal Amplification ◽  
Detection Sensitivity ◽  
Serum Samples ◽  
Rolling Circle

In this work, we demonstrate for the first time, a ferromagnetic resonance (FMR) based homogeneous and volumetric biosensor for magnetic label detection. Two different isothermal amplification methods, <i>i.e.</i>, rolling circle amplification (RCA) and loop-mediated isothermal amplification (LAMP) are adopted and combined with a standard electron paramagnetic resonance (EPR) spectrometer for FMR biosensing. For RCA-based FMR biosensor, binding of RCA products of a synthetic Vibrio cholerae target DNA sequence gives rise to the formation of aggregates of magnetic nanoparticles. Immobilization of nanoparticles within the aggregates leads to a decrease of the net anisotropy of the system and a concomitant increase of the resonance field. A limit of detection of 1 pM is obtained with an average coefficient of variation of 0.16%, which is superior to the performance of other reported RCA-based magnetic biosensors. For LAMP-based sensing, a synthetic Zika virus target oligonucleotide is amplified and detected in 20% serum samples. Immobilization of magnetic nanoparticles is induced by their co-precipitation with Mg<sub>2</sub>P<sub>2</sub>O<sub>7</sub> (a by-product of LAMP) and provides a detection sensitivity of 100 aM. The fast measurement, high sensitivity and miniaturization potential of the proposed FMR biosensing technology makes it a promising candidate for designing future point-of-care devices.<br>

Open, Microfluidic Flow Cell for Studies of Interfacial Processes at Gas−Liquid Interfaces

2006 ◽  
Vol 78 (5) ◽  
pp. 1657-1664 ◽  
Author(s):  
Khanh C. Hoang ◽  
Dmitry Malakhov ◽  
William E. Momsen ◽  
Howard L. Brockman
Keyword(s):  
Flow Cell ◽  
Liquid Interfaces ◽  
Interfacial Processes ◽  
Microfluidic Flow

scholarly journals DNA tetrahedron-mediated immune-sandwich assay for rapid and sensitive detection of PSA through a microfluidic electrochemical detection system

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Dezhi Feng ◽  
Jing Su ◽  
Yi Xu ◽  
Guifang He ◽  
Chenguang Wang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Reaction Time ◽  
Electrochemical Detection ◽  
Detection System ◽  
Detection Performance ◽  
Pdms Layer ◽  
Microfluidic Chips ◽  
Serum Samples ◽  
Gold Nanoflowers ◽  
Dna Tetrahedron

AbstractProstate-specific antigen (PSA) is the most widely used biomarker for the early diagnosis of prostate cancer. Existing methods for PSA detection are burdened with some limitations and require improvement. Herein, we developed a novel microfluidic–electrochemical (μFEC) detection system for PSA detection. First, we constructed an electrochemical biosensor based on screen-printed electrodes (SPEs) with modification of gold nanoflowers (Au NFs) and DNA tetrahedron structural probes (TSPs), which showed great detection performance. Second, we fabricated microfluidic chips by DNA TSP-Au NF-modified SPEs and a PDMS layer with designed dense meandering microchannels. Finally, the μFEC detection system was achieved based on microfluidic chips integrated with the liquid automatic conveying unit and electrochemical detection platform. The μFEC system we developed acquired great detection performance for PSA detection in PBS solution. For PSA assays in spiked serum samples of the μFEC system, we obtained a linear dynamic range of 1–100 ng/mL with a limit of detection of 0.2 ng/mL and a total reaction time <25 min. Real serum samples of prostate cancer patients presented a strong correlation between the “gold-standard” chemiluminescence assays and the μFEC system. In terms of operation procedure, cost, and reaction time, our method was superior to the current methods for PSA detection and shows great potential for practical clinical application in the future.

scholarly journals A Label and Probe-Free Zika Virus Immunosensor Prussian Blue@carbon Nanotube-Based for Amperometric Detection of the NS2B Protein

Biosensors ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 157
Author(s):  
Bárbara V. M. Silva ◽  
Marli T. Cordeiro ◽  
Marco A. B. Rodrigues ◽  
Ernesto T. A. Marques ◽  
Rosa F. Dutra
Keyword(s):  
Carbon Nanotube ◽  
Prussian Blue ◽  
Zika Virus ◽  
Point Of Care ◽  
Amperometric Detection ◽  
Cross Reactivity ◽  
Structural Protein ◽  
Serum Samples ◽  
Polypyrrole Composite ◽  
Congenital Disabilities

Zika virus (ZIKV) is a mosquito-borne infection, predominant in tropical and subtropical regions causing international concern due to the ZIKV disease having been associated with congenital disabilities, especially microcephaly and other congenital abnormalities in the fetus and newborns. Development of strategies that minimize the devastating impact by monitoring and preventing ZIKV transmission through sexual intercourse, especially in pregnant women, since no vaccine is yet available for the prevention or treatment, is critically important. ZIKV infection is generally asymptomatic and cross-reactivity with dengue virus (DENV) is a global concern. An innovative screen-printed electrode (SPE) was developed for amperometric detection of the non-structural protein (NS2B) of ZIKV by exploring the intrinsic redox catalytic activity of Prussian blue (PB), incorporated into a carbon nanotube–polypyrrole composite. Thus, this immunosensor has the advantage of electrochemical detection without adding any redox-probe solution (probe-less detection), allowing a point-of-care diagnosis. It was responsive to serum samples of only ZIKV positive patients and non-responsive to negative ZIKV patients, even if the sample was DENV positive, indicating a possible differential diagnosis between them by NS2B. All samples used here were confirmed by CDC protocols, and immunosensor responses were also checked in the supernatant of C6/36 and in Vero cell cultures infected with ZIKV.

scholarly journals Fabry Cardiomyopathy: Current Practice and Future Directions

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1532
Author(s):  
Jeffrey Yim ◽  
Olivia Yau ◽  
Darwin F. Yeung ◽  
Teresa S. M. Tsang
Keyword(s):  
Fabry Disease ◽  
Early Stage ◽  
Point Of Care ◽  
Left Ventricular ◽  
The Body ◽  
Cardiac Biomarkers ◽  
Dried Blood Spot ◽  
Point Of Care Ultrasound ◽  
Enzyme Replacement ◽  
Blood Spot

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations in the galactosidase A (GLA) gene that result in deficient galactosidase A enzyme and subsequent accumulation of glycosphingolipids throughout the body. The result is a multi-system disorder characterized by cutaneous, corneal, cardiac, renal, and neurological manifestations. Increased left ventricular wall thickness represents the predominant cardiac manifestation of FD. As the disease progresses, patients may develop arrhythmias, advanced conduction abnormalities, and heart failure. Cardiac biomarkers, point-of-care dried blood spot testing, and advanced imaging modalities including echocardiography with strain imaging and magnetic resonance imaging (MRI) with T1 mapping now allow us to detect Fabry cardiomyopathy much more effectively than in the past. While enzyme replacement therapy (ERT) has been the mainstay of treatment, several promising therapies are now in development, making early diagnosis of FD even more crucial. Ongoing initiatives involving artificial intelligence (AI)-empowered interpretation of echocardiographic images, point-of-care dried blood spot testing in the echocardiography laboratory, and widespread dissemination of point-of-care ultrasound devices to community practices to promote screening may lead to more timely diagnosis of FD. Fabry disease should no longer be considered a rare, untreatable disease, but one that can be effectively identified and treated at an early stage before the development of irreversible end-organ damage.

scholarly journals Low Power Contactless Bioimpedance Sensor for Monitoring Breathing Activity

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2081
Author(s):  
Marko Pavlin ◽  
Franc Novak ◽  
Gregor Papa
Keyword(s):  
Dielectric Properties ◽  
Low Power ◽  
Medical Application ◽  
Fast Response ◽  
The Body ◽  
Frequency Change ◽  
Tissue Composition ◽  
Medical Sector ◽  
Bioimpedance Measurement ◽  
Wide Operating

An electronic circuit for contactless detection of impedance changes in a tissue is presented. It operates on the principle of resonant frequency change of the resonator having the observed tissue as a dielectric. The operating frequency reflects the tissue dielectric properties (i.e., the tissue composition and on the tissue physiological changes). The sensor operation was tested within a medical application by measuring the breathing of a patient, which was an easy detectable physiological process. The advantage over conventional contact bioimpedance measurement methods is that no direct contact between the resonator and the body is required. Furthermore, the sensor’s wide operating range, ability to adapt to a broad range of measured materials, fast response, low power consumption, and small outline dimensions enables applications not only in the medical sector, but also in other domains. This can be extended, for example, to food industry or production maintenance, where the observed phenomena are reflected in dynamic dielectric properties of the observed object or material.

scholarly journals A rapid point-of-care assay accurately measures vitamin D

2021 ◽  
Author(s):  
K. Albrecht ◽  
J. Lotz ◽  
L. Frommer ◽  
K. J. Lackner ◽  
G. J. Kahaly
Keyword(s):  
Vitamin D ◽  
Metabolic Pathways ◽  
Point Of Care ◽  
Immunofluorescence Assay ◽  
Laboratory Method ◽  
Controlled Study ◽  
Mean Deviation ◽  
Serum Samples ◽  
Assay Validation ◽  
Accuracy And Precision

Abstract Purpose Vitamin D (VitD) is a pleiotropic hormone with effects on a multitude of systems and metabolic pathways. Consequently, the relevance of a sufficiently high VitD serum level becomes self-evident. Methods A rapid immunofluorescence assay designed for the point-of-care measurement of serum VitD3 solely was tested. Inter- and intra-assay validation, double testing and result comparison with a standardized laboratory method were performed. Results An overall linear correlation of r = 0.89 (Pearson, 95% CI 0.88–0.92, p < 0.01) between the point of care and the conventional reference assay was registered. Accuracy and precision were of special interest at cut-points (10 ng/ml [mean deviation 1.7 ng/ml, SD 1.98 ng/ml, SE 0.16 ng/ml], 12 ng/ml [MD 0.41, SD 1.89, SE 0.19] and 30 ng/ml [MD − 1.11, SD 3.89, SE 0.35]). Only a slight deviation was detected between the two assays when using fresh (r = 0.91, 95% CI 0.86–0.94, p < 0.01) and frozen serum samples (r = 0.86, 0.82–0.89, p < 0.01). Results remained steady when samples were frozen several times. Inter- and intra-assay validation according to the CLSI protocol as well as multiuser testing showed stable results. Conclusion This novel, innovative, and controlled study indicates that the evaluated rapid point of care VitD assay is reliable, accurate, and suited for clinical practice.

Amine functionalized graphene oxide/CNT nanocomposite for ultrasensitive electrochemical detection of trinitrotoluene

2013 ◽  
Vol 248-249 ◽  
pp. 322-328 ◽  
Author(s):  
Kavita Sablok ◽  
Vijayender Bhalla ◽  
Priyanka Sharma ◽  
Roohi Kaushal ◽  
Shilpa Chaudhary ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Detection ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Amine Functionalized

scholarly journals Colorimetry-Based Detection of Nitric Oxide from Exhaled Breath for Quantification of Oxidative Stress in Human Body

Healthcare ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1055
Author(s):  
Muni Raj Maurya ◽  
Haseena Onthath ◽  
Hagar Morsy ◽  
Najam-US-Sahar Riyaz ◽  
Muna Ibrahim ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Human Body ◽  
Ph Effect ◽  
High Sensitivity ◽  
Fast Response ◽  
The Body ◽  
Bromophenol Blue ◽  
Exhaled Breath ◽  
Vis Spectroscopy

Monitoring exhaled breath is a safe, noninvasive method for determining the health status of the human body. Most of the components in our exhaled breath can act as health biomarkers, and they help in providing information about various diseases. Nitric oxide (NO) is one such important biomarker in exhaled breath that indicates oxidative stress in our body. This work presents a simple and noninvasive quantitative analysis approach for detecting NO from exhaled breath. The sensing is based on the colorimetric assisted detection of NO by m-Cresol Purple, Bromophenol Blue, and Alizaringelb dye. The sensing performance of the dye was analyzed by ultraviolet–visible (UV–Vis) spectroscopy. The study covers various sampling conditions like the pH effect, temperature effect, concentration effect, and selective nature of the dye. The m-Cresol Purple dye exhibited a high sensitivity towards NO with a detection limit of ~0.082 ppm in the linear range of 0.002–0.5 ppm. Moreover, the dye apprehended a high degree of selectivity towards other biocompounds present in the breath, and no possible interfering cross-reaction from these species was observed. The dye offered a high sensitivity, selectivity, fast response, and stability, which benchmark its potential for NO sensing. Further, m-Cresol Purple dye is suitable for NO sensing from the exhaled breath and can assist in quantifying oxidative stress levels in the body for the possible detection of COVID-19.

scholarly journals Point-of-care high-sensitivity assay on PATHFAST as the backup in the emergency room

2021 ◽  
Vol 5 ◽  
pp. 239920262110550
Author(s):  
Joško Osredkar ◽  
Katja Krivic ◽  
Teja Fabjan ◽  
Kristina Kumer ◽  
Jure Tršan ◽  
...  
Keyword(s):  
Blood Serum ◽  
Troponin I ◽  
Point Of Care ◽  
High Sensitivity ◽  
Turnaround Time ◽  
Serum Samples ◽  
Linear Relationships ◽  
Accuracy And Precision ◽  
Laboratory Results ◽  
Key Indicators

Aim: Although the levels of cardiac troponin I (cTnI) have proved to be a useful diagnostic biomarker of acute myocardial infarction, there are a wide variety of point-of-care (POC) analysers, which provide measurements of cTnI. The aim of this study was to compare the results obtained by the ADVIA Centaur ultra-assay cTnI assay (us-cTnI), ADVIA Centaur high-sensitive cTnI assay (hs-cTnI) and a POC high-sensitivity assay using PATHFAST. We also aimed to explore total turnaround time (TAT) for laboratory results using the POC PATHFAST analyser. Methods: Samples from 161 patients were taken. Of these samples, 129 were tested with all three assays (us-cTnI, hs-cTnI and PATHFAST), and 32 samples were tested on PATHFAST for the comparison of whole blood, serum and plasma. Results: Comparison of the POC testing methods in this study demonstrated that there are strong linear relationships between all three cTnI assays (us-cTnI, hs-cTnI and POC on PATHFAST). Furthermore, we also show there are strong linear relationships between the two high-sensitive cTnI assays (hs-cTnI and PATHFAST) for blood serum samples, as determined by Passing–Bablok regression analyses. In our comparison of our new data with our older study, the TAT went down. Conclusion: The timeliness of laboratory results is, in addition to accuracy and precision, one of the key indicators of laboratory performance, and at the same time has a significant impact on the course of the patient’s condition. It is therefore important that the laboratory strives to meet the expectations of clinicians regarding the time from the order to the result of the analysis.

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