Evaluation of In-Flow Magnetoresistive Chip Cell—Counter as a Diagnostic Tool

Inexpensive simple medical devices allowing fast and reliable counting of whole cells are of interest for diagnosis and treatment monitoring. Magnetic-based labs on a chip are one of the possibilities currently studied to address this issue. Giant magnetoresistance (GMR) sensors offer both great sensitivity and device integrability with microfluidics and electronics. When used on a dynamic system, GMR-based biochips are able to detect magnetically labeled individual cells. In this article, a rigorous evaluation of the main characteristics of this magnetic medical device (specificity, sensitivity, time of use and variability) are presented and compared to those of both an ELISA test and a conventional flow cytometer, using an eukaryotic malignant cell line model in physiological conditions (NS1 murine cells in phosphate buffer saline). We describe a proof of specificity of a GMR sensor detection of magnetically labeled cells. The limit of detection of the actual system was shown to be similar to the ELISA one and 10 times higher than the cytometer one.

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A tandem giant magnetoresistance assay for one-shot quantification of clinically relevant concentrations of N-terminal pro-B-type natriuretic peptide in human blood

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-021-03227-5 ◽

2021 ◽

Author(s):

Fanda Meng ◽

Weisong Huo ◽

Jie Lian ◽

Lei Zhang ◽

Xizeng Shi ◽

...

Keyword(s):

Detection Limit ◽

Giant Magnetoresistance ◽

Dynamic Range ◽

Point Of Care ◽

Sample Volume ◽

Small Sample ◽

Broad Dynamic Range ◽

Gmr Sensors ◽

Gmr Sensor ◽

Sample Volume Requirement

AbstractWe report a microfluidic sandwich immunoassay constructed around a dual-giant magnetoresistance (GMR) sensor array to quantify the heart failure biomarker NT-proBNP in human plasma at the clinically relevant concentration levels between 15 pg/mL and 40 ng/mL. The broad dynamic range was achieved by differential coating of two identical GMR sensors operated in tandem, and combining two standard curves. The detection limit was determined as 5 pg/mL. The assay, involving 53 plasma samples from patients with different cardiovascular diseases, was validated against the Roche Cobas e411 analyzer. The salient features of this system are its wide concentration range, low detection limit, small sample volume requirement (50 μL), and the need for a short measurement time of 15 min, making it a prospective candidate for practical use in point of care analysis.

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Biosensor Based on Giant Magnetoresistance Material

International Journal of E-Health and Medical Communications ◽

10.4018/jehmc.2010070101 ◽

2010 ◽

Vol 1 (3) ◽

pp. 1-15 ◽

Cited By ~ 4

Author(s):

Mitra Djamal

Keyword(s):

Giant Magnetoresistance ◽

Large Scale ◽

Single Chip ◽

Biomolecule Detection ◽

Novel Approach ◽

Large Scale Integration ◽

Gmr Sensors ◽

Gmr Sensor ◽

Scale Integration ◽

The Magnetic Field

In recent years, giant magnetoresistance (GMR) sensors have shown a great potential as sensing elements for biomolecule detection. The resistance of a GMR sensor changes with the magnetic field applied to the sensor, so that a magnetically labeled biomolecule can induce a signal. Compared with the traditional optical detection that is widely used in biomedicine, GMR sensors are more sensitive, portable, and give a fully electronic readout. In addition, GMR sensors are inexpensive and the fabrication is compatible with the current VLSI (Very Large Scale Integration) technology. In this regard, GMR sensors can be easily integrated with electronics and microfluidics to detect many different analytes on a single chip. In this article, the authors demonstrate a comprehensive review on a novel approach in biosensors based on GMR material.

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Giant Magnetoresistance Imaging for NDE of Conductive Materials

MRS Proceedings ◽

10.1557/proc-591-151 ◽

1999 ◽

Vol 591 ◽

Cited By ~ 1

Author(s):

E. S. Boltz ◽

S. G. Albanna ◽

A. R. Stallings ◽

Y. H. Spooner ◽

J. P. Abeyta

Keyword(s):

Eddy Current ◽

Giant Magnetoresistance ◽

High Spatial Resolution ◽

Low Frequency ◽

High Sensitivity ◽

Low Noise ◽

Conductive Materials ◽

Gmr Sensors ◽

Current Sensors ◽

Gmr Sensor

ABSTRACTTraditional coil-based eddy-current sensors are severely limited in their ability to detect small buried defects, defects under fasteners and deeply buried cracks and corrosion. TPL has developed eddy-current sensors and arrays based on the use of Giant Magnetoresistance (GMR) sensor elements. GMR offers high sensitivity, very wide bandwidth and low noise from DC to over 1 GHz. Coupled with the ability to fabricate GMR sensors with micron-level dimensions, these new eddy-current sensors offer an ideal technology for inspections requiring high spatial resolution and low-frequency, deeply-penetrating fields.

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Biosensor Based on Giant Magnetoresistance Material

Emerging Communication Technologies for E-Health and Medicine ◽

10.4018/978-1-4666-0909-9.ch008 ◽

2012 ◽

pp. 107-122 ◽

Cited By ~ 1

Author(s):

Mitra Djamal ◽

Ramli ◽

Yulkifli ◽

Suprijadi ◽

Khairurrijal

Keyword(s):

Giant Magnetoresistance ◽

Large Scale ◽

Single Chip ◽

Biomolecule Detection ◽

Novel Approach ◽

Large Scale Integration ◽

Gmr Sensors ◽

Gmr Sensor ◽

Scale Integration ◽

The Magnetic Field

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Construction of a Magnetic Biosensor for Pathogen Detection

Journal of Medical Devices ◽

10.1115/1.2936202 ◽

2008 ◽

Vol 2 (2) ◽

Cited By ~ 2

Author(s):

Yuanpeng Li ◽

Marlene Castro ◽

Hyungsoon Im ◽

Xiaofeng Yao ◽

Sang-Hyun Oh ◽

...

Keyword(s):

Magnetic Nanoparticles ◽

Giant Magnetoresistance ◽

Pathogen Detection ◽

Gold Surface ◽

Thiol Group ◽

Microfluidic System ◽

Microfluidic Channels ◽

Resistance Change ◽

Gmr Sensors ◽

Gmr Sensor

Current methods for pathogen detection require days before a result is available, while biosensors offer the advantage of quick, on the spot results. In this project we present the proof of concept of a biosensor that uses giant magnetoresistance (GMR) sensors and a microfluidic system. The bioprobe consists of a 30 bp oligonucleotide, 5′ functionalized with a thiol group (T-DNA30) immobilized on a gold surface. Hybridization was tested with a 5′-biotinylated oligonucleotide complementary to T-DNA30 to which Streptavidin-R-Phycoerythrin was attached later. The difference in fluorescence between the target sample and control samples was observed using a scanning laser confocal fluorescence microscope. The GMR device consists of an Ir0.8Mn0.2∕Co0.9Fe0.1∕Cu∕Co0.9Fe0.1∕Ni0.82Fe0.12 multilayer structure. Magnetic nanoparticles were deposited directly on the surface of the GMR sensors. An external magnetic field was employed to polarize the nanoparticles, which can then be detected by comparing the resistance change loops of the GMR sensors before and after their deposition. A transparent elastomer, polydimethylsiloxane (PDMS), was used for the microfluidic system. The system comprises two microfluidic channels separated by a 200μm PDMS wall. The channel width is 200μm and its height 100μm. The PDMS channel was permanently bonded to the SiO2 surface of the GMR sensor. The integrated biosensor will immobilize thiolated DNA on the gold surface below which the GMR device is located. For hybridization, biotinylated DNA will be used. Finally, magnetic nanoparticles, coated with streptavidin will be attached to the hybridized DNA and detected by the GMR device.

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Two-step thinning fabrication of giant magnetoresistance sensors for flexible applications

Modern Physics Letters B ◽

10.1142/s021798491450081x ◽

2014 ◽

Vol 28 (10) ◽

pp. 1450081 ◽

Cited By ~ 1

Author(s):

Cong Yin ◽

Dan Xie ◽

Jian-Long Xu ◽

Tian-Ling Ren

Keyword(s):

Inductively Coupled Plasma ◽

Giant Magnetoresistance ◽

Ion Beam ◽

Spin Valve ◽

Mechanical Damage ◽

Inductively Coupled ◽

Icp Etching ◽

Gmr Sensors ◽

Flexible Applications ◽

Gmr Sensor

Spin valve giant magnetoresistance (GMR) sensors were prepared by a two-step thinning method combining grind thinning and inductively coupled plasma (ICP) etching together. The fabrication processes of front GMR sensors and backside ICP etching were described in detail. Magnetoresistance ratio of about 4.24% and coercive field of approximately 11 Oe were obtained in a tested bendable GMR sensor. The variations of the magnetic property in GMR sensors were explained mainly from the temperature, ion beam damage and mechanical damage generated by the fabrication process.

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Heat Inactivation of Different Types of SARS-CoV-2 Samples: What Protocols for Biosafety, Molecular Detection and Serological Diagnostics?

Viruses ◽

10.3390/v12070735 ◽

2020 ◽

Vol 12 (7) ◽

pp. 735 ◽

Cited By ~ 18

Author(s):

Boris Pastorino ◽

Franck Touret ◽

Magali Gilles ◽

Xavier de Lamballerie ◽

Remi N. Charrel

Keyword(s):

Infected Cell ◽

Limit Of Detection ◽

Elisa Test ◽

Cell Culture Supernatant ◽

Heat Inactivation ◽

Standard Precautions ◽

Viral Loads ◽

Human Sera ◽

European Norm ◽

C 30

Standard precautions to minimize the risk of SARS-CoV-2 transmission implies that infected cell cultures and clinical specimens may undergo some sort of inactivation to reduce or abolish infectivity. We evaluated three heat inactivation protocols (56 °C-30 min, 60 °C-60 min and 92 °C-15 min) on SARS-CoV-2 using (i) infected cell culture supernatant, (ii) virus-spiked human sera (iii) and nasopharyngeal samples according to the recommendations of the European norm NF EN 14476-A2. Regardless of the protocol and the type of samples, a 4 Log10 TCID50 reduction was observed. However, samples containing viral loads > 6 Log10 TCID50 were still infectious after 56 °C-30 min and 60 °C-60 min, although infectivity was < 10 TCID50. The protocols 56 °C-30 min and 60 °C-60 min had little influence on the RNA copies detection, whereas 92 °C-15 min drastically reduced the limit of detection, which suggests that this protocol should be avoided for inactivation ahead of molecular diagnostics. Lastly, 56 °C-30 min treatment of serum specimens had a negligible influence on the results of IgG detection using a commercial ELISA test, whereas a drastic decrease in neutralizing titers was observed.

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