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MA: Fachverband Magnetismus

MA 9: Magnetic Nanoparticles

MA 9.8: Vortrag

Montag, 31. März 2014, 17:00–17:15, HSZ 401

Microfluidic device using anchored one-dimensional, chain-like superstructures of superparamagnetic beads for controllable particle filtering — •Patrick Stohmann, Bernhard Eickenberg, and Andreas Hütten — Department of Physics, Thin Film and Physics of Nanostructures, University of Bielefeld, D-33615 Bielefeld, Germany

Superparamagnetic beads are of interest for microfluidic applications. They can be manipulated via external homogeneous magnetic fields and their functionalized surface allows for the immobilization of various bio-molecules. The presence of an external magnetic field results in an alignment of the particles to chain-like superstructures. When the magnetic field is rotated, the chains follow the movement of the field. Inside a microfluidic channel, the ends of the chains can be anchored on the bottom of the channel. Based on this method, a microfluidic particle filter device was developed that allows for controlling its filter activity by changing the direction of the external field. A regular pattern of anchorbeads was created on the channel bottom by standard lithography. This pattern serves as a substructure for the field-induced agglomeration of magnetic chains. A magnetic field perpendicular to the channel bottom causes the chains to protrude into the liquid flow. Switching the field direction by 90° yields a rapid decrease of the chain-liquid-interaction. The microfluidic particle filter device may enhance the functionality of lab-on-a-chip systems. Chemical interactions of specific dissolved particles with the surface functionalization of the beads may realize on-demand filtering of molecules or cells.