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On the importance of sensor height variation for detection of magnetic labels by magnetoresistive sensors.

TitleOn the importance of sensor height variation for detection of magnetic labels by magnetoresistive sensors.
Publication TypeJournal Article
Year of Publication2015
AuthorsHenriksen ADahl, Wang SXiang, Hansen MFougt
JournalSci Rep
Volume5
Pagination12282
Date Published2015
ISSN2045-2322
Abstract

Magnetoresistive sensors are widely used for biosensing by detecting the signal from magnetic labels bound to a functionalized area that usually covers the entire sensor structure. Magnetic labels magnetized by a homogeneous applied magnetic field weaken and strengthen the applied field when they are over and outside the sensor area, respectively, and the detailed origin of the sensor signal in experimental studies has not been clarified. We systematically analyze the signal from both a single sensor stripe and an array of sensor stripes as function of the geometrical parameters of the sensor stripes as well as the distribution of magnetic labels over the stripes. We show that the signal from sensor stripes with a uniform protective coating, contrary to conventional wisdom in the field, is usually dominated by the contribution from magnetic labels between the sensor stripes rather than by the labels on top of the sensor stripes because these are at a lower height. We therefore propose a shift of paradigm to maximize the signal due to magnetic labels between sensor stripes. Guidelines for this optimization are provided and illustrated for an experimental case from the literature.

DOI10.1038/srep12282
Alternate JournalSci Rep
PubMed ID26195089
PubMed Central IDPMC4508666
Grant List1U19AI110491 / AI / NIAID NIH HHS / United States
R44 CA165296 / CA / NCI NIH HHS / United States
U01CA152737 / CA / NCI NIH HHS / United States
U54CA143907 / CA / NCI NIH HHS / United States
U54CA151459 / CA / NCI NIH HHS / United States