Controlled counter-flow motion of magnetic bead chains rolling along microchannels

10.11.2010

Karle M, Wöhrle J, Miwa J, Paust N, Roth G, Zengerle R, von Stetten F

Microfluid Nanofluid (2011) 10:935–939

Microfluid Nanofluid      online article

We demonstrate controlled transport of superparamagnetic beads in the opposite direction of a laminar flow. A permanent magnet assembles 200 nm magnetic particles into long bead chains parallel to the magnetic field lines. A rotation of the magnet results in a rotation of the bead chains in the opposite direction, up to a maximum counter-flow velocity of 8 mm s-1. Like this, magnetic beads can be accurately manoeuvred. This counter-flow motion can be efficiently be used in Lab-on-a-Chip systems.