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

作者：Loureiro J^*; Fermon C; Pannetier Lecoeur M; Arrias G; Ferreira R; Cardoso S; Freitas P P

来源：IEEE Transactions on Magnetics, 2009, 45(10): 4873-4876.

DOI：10.1109/TMAG.2009.2026287

• Chip-cytometer
• magnetic beads
• magnetoresistive sensors
• microfluidics

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 mu Vp-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.

• 出版日期2009-10
• 单位中国地震局