Magnetoresistive Detection of Magnetic Beads Flowing at High Speed in Microfluidic Channels

Author

Loureiro, J. ; Fermon, C. ; Pannetier-Lecoeur, M. ; Arrias, G. ; Ferreira, R. ; Cardoso, S. ; Freitas, P.P.

Author_Institution

INESC-MN Inst. de Eng. de Sist. e Comput. - Microsistemas e Nanotecnologias, Inst. for Nanosci. & Nanotechnol., Lisbon, Portugal

Volume

45

Issue

10

fYear

2009

Firstpage

4873

Lastpage

4876

Abstract

An integrated device including microfluidic channels and incorporated magnetoresistive spin valve sensors has been developed and used to detect single magnetic bead motion at cm/s velocities. The sensitivity of the system is high enough to determine the magnetic orientation, the flowing height and the speed of each particle for velocities between 10-23 mm/s and the counting capability of the device is fully working for this range of velocities and below this limit. Sensor signals (between 3-100 muVp-p) correspond to bead moments at different directions indicating a physical rotation of the beads, and a slow response (seconds) of the bead moment to magnetizing field changes. Subsequent magnetic characterization of the micron-sized beads indicates that they are composed of strongly interacting magnetic nanoparticles.

Keywords

flow sensors; magnetic particles; magnetic sensors; magnetisation; magnetohydrodynamics; microchannel flow; nanoparticles; spin valves; flowing height; integrated device; magnetic characterization; magnetic nanoparticles; magnetic orientation; magnetizing field; magnetoresistive detection; magnetoresistive spin valve sensors; microfluidic channels; physical rotation; single magnetic bead motion; velocity 10 mm/s to 23 mm/s; Chip-cytometer; magnetic beads; magnetoresistive sensors; microfluidics;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2009.2026287

Filename

5257180