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Bead Capture on Magnetic Sensors in a Microfluidic System

2009; IEEE Sensors Council; Volume: 9; Issue: 6 Linguagem: Inglês

10.1109/jsen.2009.2021122

1558-1748

Frederik Westergaard Østerberg, Bjarke Thomas Dalslet, Christian Danvad Damsgaard, Susana Cardoso, P. P. Freitas, Mikkel Fougt Hansen,

Microfluidic and Bio-sensing Technologies

The accumulation of magnetic beads by gravitational sedimentation and magnetic capture on a planar Hall-effect sensor integrated in a microfluidic channel is studied systematically as a function of the bead concentration, the fluid flow rate, and the sensor bias current. It is demonstrated that the sedimentation flux is proportional to the bead concentration and has a power law relation to the fluid flow rate. The mechanisms for the bead accumulation are investigated and it is found that gravitational sedimentation dominates the bead accumulation, whereas the stability of the sedimented beads against the fluid flow is defined by the localized magnetic fields from the sensor.