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Dielectrophoretic particle chromatographie (DPC) at preparative scale (SPP 2045)

The dielectrophoretic chromatography (DPC) is a separation process which addresses a wide range of synthetic and biological micro particles. Dielectrophoresis is referred to as the movement of particles caused by inhomogeneous electric fields, whereas chromatography indicates a process, which separates particles (0.2 μm- 10 μm) by retardation. In a microfluidic DPC-device interdigitated electrodes (IDE) induce highly inhomogeneous electrical fields. Their areas of highest field gradients act on the mobile phase, the dispersion, like the stationary phase does in ordinary chromatography.An injected liquid carries a particle suspension through the flow cell. By applying an AC voltage to IDE an inhomogeneous electric field is generated in the flow channel. This leads to polarization of particles and consequently to dieletrophoresis of the microparticles.

  • Image : Electric field below electrodes. In an inhomogeneous electric field a polarizable particle gets influenced by dielectrophoresis.

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  • Image : Principle of dielectrophoretic particle chromatography. The electrical field is pulsed (activated/deactivated).
    Activated electrical field: Particles get accelerated due to dielectrophoretic force. Deactivated electrical Field: Due to gravity and diffusion, particles move back into the fluid. The forces shown depend upon the size of the particles and thus enable a chromatographic separation of the particles.

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  • Schematic diagram of the dielectrophoretic particle chromatography. The separation process is based on different mobilities of the particles in a inhomogeneous electrical field.

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  • Schaubild eines PDMS Kanals auf Mikroelektroden.

    Image: Microfluidic device for dielectrophoretic particle chromatography. A constant fluid flow carries particles through a meandering channel. The bottom of the channel is given by an array of electrodes on top of a transparent substrate.

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Their induced mobility depends on their dielectric properties and thus on their size, shape and material. Particles with a high dielectrophoretic mobility move faster towards the IDE and get immobilized more quickly than those with a low mobility, which leads to a fractionation of the suspended particles.In this project it is intended to shed some light on the grounds for the DPC's potential capability to fractionate particles according to their size, shape and material and in dependence of throughput. This understanding shall pave the way for scaling-up such a separation process and to evaluate its potential as a characterization technology for microparticles.

 

 

Contact:

Giesler, Jasper, M. Sc.
Room UFT 2110
Fon: 0421- 218 - 63495

j.gieslerprotect me ?!uni-bremenprotect me ?!.de

Further information

DFG priority program "MehrDimPart" (SPP 2045).
Project B12.