GMR sensors: Magnetoresistive behaviour optimization for biological detection by means of superparamagnetic nanoparticles

An immunomagnetic method for the selective and quantitative detection of biological species by means of a magnetoresistive biosensor and superparamagnetic particles has been optimized. In order to achieve this, a giant magnetoresistive [Co (5.10 nm)/Cu (2.47 nm)] 20 multilayer structure has been cho...

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Bibliographic Details
Published in:Biosensors & bioelectronics 2011-04, Vol.26 (8), p.3705-3709
Main Authors: Manteca, A., Mujika, M., Arana, S.
Format: Article
Language:English
Subjects:
Bioelectricity
Biological
Biological and medical sciences
BioMEMS
Biosensing Techniques - instrumentation
Biosensors
Biotechnology
Carriers
Fundamental and applied biological sciences. Psychology
GMR
Magnetic particles
Magnetics - instrumentation
Magnetite Nanoparticles - chemistry
Magnetoresistance
Materials selection
Multilayers
SAM
Self-assembled monolayers
Sensors
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Summary:An immunomagnetic method for the selective and quantitative detection of biological species by means of a magnetoresistive biosensor and superparamagnetic particles has been optimized. In order to achieve this, a giant magnetoresistive [Co (5.10 nm)/Cu (2.47 nm)] 20 multilayer structure has been chosen as the sensitive material, showing a magnetoresistance of 3.60% at 215 Oe and a sensitivity up to 0.19 Ω/Oe between 145 Oe and 350 Oe. The outward gold surface of the sensor is biofunctionalized with a Self-Assembled Monolayer (SAM). In addition, three different types of magnetic labels have been tested. 2 μm diameter magnetic carriers (7.68 pg ferrite/particle) have shown the best response and they have induced a shift in the magnetoresistive hysteresis loops up to 9% at 175 Oe.
ISSN:0956-5663
1873-4235
DOI:10.1016/j.bios.2011.02.013