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Manipulation of cells by dielectrophoresis – the effect of EHD

Manipulation of cells by dielectrophoresis – the effect of EHD. By Lionel Broche With the help of Kai Hoettges Biomedical Engineering Group Supervisors: M.P.Hughes, S.Ogin, G.E.N.Kass. Summary. Principles of experimentation with dielectrophoretic forces

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Manipulation of cells by dielectrophoresis – the effect of EHD

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  1. Manipulation of cells by dielectrophoresis – the effect of EHD By Lionel Broche With the help of Kai Hoettges Biomedical Engineering Group Supervisors: M.P.Hughes, S.Ogin, G.E.N.Kass www.surrey.ac.uk

  2. Summary • Principles of experimentation with dielectrophoretic forces • Observations at low-frequency: the EHD effect • Presentation of the theory of EHD

  3. Manipulation of cells by dielectrophoresis – the effect of EHD Principles of experimentation with dielectrophoretic forces

  4. Principles of experimentation with dielectrophoretic forces Suspension medium em, sm Membrane ed, sd Cytoplasm ec, sc

  5. Principles of experimentation with dielectrophoretic forces E

  6. Principles of experimentation with dielectrophoretic forces E

  7. Principles of experimentation with dielectrophoretic forces E

  8. Principles of experimentation with dielectrophoretic forces E

  9. Principles of experimentation with dielectrophoretic forces E FDEP

  10. Principles of experimentation with dielectrophoretic forces E FDEP

  11. Principles of experimentation with dielectrophoretic forces Suspension medium em, sm Membrane FDEP ed, sd Cytoplasm ec, sc E

  12. Principles of experimentation with dielectrophoretic forces Suspension medium em, sm 2.r -Q Q E

  13. Principles of experimentation with dielectrophoretic forces • DEP theory for spherical particles: FDEP = 4p.r3.em.e0.Re(K(w)).E2 DEP force Dipole-related factor Cell radius

  14. Principles of experimentation with dielectrophoretic forces 1kHz 7kHz 50kHz 350kHz 2MHz 14MHz

  15. Principles of experimentation with dielectrophoretic forces • The DEP spectrum: FDEP Frequency (Hz)

  16. Principles of experimentation with dielectrophoretic forces Electrode 1 Gap Electrode 2

  17. Principles of experimentation with dielectrophoretic forces • The experiments give a measure of the DEP force for different frequencies of the signal • The result can be used in several ways (detection, measure…)

  18. Manipulation of cells by dielectrophoresis – the effect of EHD Observations at low-frequency: the EHD effect

  19. Observations at low-frequency: the EHD effect • Low-frequency is <40kHz • Observation of parasitic flows

  20. Observations at low-frequency: the EHD effect Electrode 1 Gap Electrode 2

  21. Observations at low-frequency: the EHD effect Electrode 1 Gap Electrode 2

  22. Observations at low-frequency: the EHD effect • Electro-HydroDynamics: EHD • Caused by the electronic double-layer

  23. Manipulation of cells by dielectrophoresis – the effect of EHD Presentation of the theory of EHD

  24. Presentation of the theory of EHD • Navier-Stokes equation: Gravitation Visquous forces Negligible since Re<<1 Electric forces Pressure

  25. Presentation of the theory of EHD • The electric force equation: Coulomb forces Dielectric forces

  26. Presentation of the theory of EHD • The electric force equation: Coulomb forces >> Dielectric forces w<< EHD

  27. Presentation of the theory of EHD • The electric force equation: Coulomb forces << Dielectric forces w >> Electro-thermal forces

  28. Presentation of the theory of EHD ~nm Water Electrode Substrate

  29. Presentation of the theory of EHD

  30. Presentation of the theory of EHD

  31. Presentation of the theory of EHD • Enhanced DEP trapping • Fluid pumping • Others…

  32. Presentation of the theory of EHD Thank you for your attention

  33. References • Castellanos, Ramos et al. (2003), “Electrohydrodynamics and dielectrophoresis in microsystems: Scaling laws”, Journal of Physics D: Applied Physics, 36(20): 2584 • Hoettges, McDonnell et al. (2003), “Use of combined dielectrophoresis / electrohydrodynamics forces for biosensor enhancement”, Journal of Physics D: Applied Physics, 36(20): 101-104

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