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Three-Dimensional Dielectrophoresis Device with Integrated Actuating and Impedance Sensing

Explore a groundbreaking lab-on-a-chip technology integrating actuation and impedance sensing for microscale experiments. Discover the application of dielectrophoresis theory, device fabrication methods, and novel impedance sensing techniques. This device is specially designed for biological and medical purposes, offering efficient particle manipulation and concentration.

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Three-Dimensional Dielectrophoresis Device with Integrated Actuating and Impedance Sensing

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  1. Three-Dimensional Dielectrophoresis Device with Integrated Actuating and Impedance Sensing Michael Beltran Robert Lam Bryan Lochman 12/14/07

  2. Lab on a chip • Lab on a chip technology will reduce the size of complex experimental setups. • Eliminate large, bulky equipment. • Move lab experiments to a non-lab environment. • Especially useful in biological and medical fields for local use.

  3. Overview • Device Overview • Theory • Dielectrophoresis (DEP) • DEP cage actuation • Impedance sensing • Device Fabrication • Previous Devices • Results • Parasitic Cages • Particle Concentration • Recommendations • Micro-scale device

  4. Device Overview • 1cm electrode strips • Induced DEP Cages • Top conductive sealing layer • Integrated actuation and sensing Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  5. Theory Dielectrophoresis (DEP) www-dsv.cea.fr/.../Image/Pascal/biopuces_64.jpg

  6. Theory DEP – Governing Equation • r – radius • E – nonuniform electric field • - permittivity of medium • Re[K] – Clasius-Mossotti Factor where

  7. Theory DEP - Permittivity • σ = conductivity of electric field • ω = angular frequency of electric field • Varying these two variables will alter the permittivity of the particle/medium

  8. Theory DEP - Clausius-Mossotti • At low frequences: • At high frequencies: • Polarization Factor (K) can be switched between positive or negative values

  9. Theory DEP – Vertical Forces • Buoyancy Force: • DEP and Buoyancy: Iliescu, C.; Yu, L.; Xu, G.; Tay, F. A Dielectrophoretic Chip With a 3-D Electric Field Gradient, Journal of Microelectromechanical Systems, 2006, 15, 1506-1513

  10. Theory DEP – Ratio between DEP, Viscous forces • FDEP = volume (~r3) • Fviscous = surface (~r2) • Smaller particles will move slower

  11. Theory DEP – Cage Actuation • Progressively alternating electrode signals move particles towards target electrode • Provides better sensing of particles Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  12. Theory DEP – Cage Actuation • The DEP Cages are able to move toward a target electrode by moving the counter phase signal to the next electrode closer to the target Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  13. Theory Impedance Sensing • To measure the concentration of particles impedance sensing is used • All electrodes are switched to ground except the sensing electrode • The sensing electrode is connected to a transimpedance amplifier Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  14. Theory Impedance Sensing – Transfer Function • Transfer function of the transimpedance amplifier: • RM and CM are the resistance and capacitance between the electrode and lid • RF and CF are the feedback resistance and capacitance • There are two sensing frequency ranges, low and high, if the same signal is used for both DEP cage formation and sensing

  15. Theory Impedance Sensing at low frequencies • Low Frequency • When w<<1/(RMCM) and w<<1/(RFCF) the sensing equation is: • The Clausius Mossotti factor at low frequencies, shows that a particle will only be trapped in the DEP cage if its conductivity is lower than the mediums giving rise to : • These two equations show the output voltage will decrease with particles at low frequencies

  16. Theory Impedance Sensing at high frequencies • High Frequency • When w>>1/(RMCM) and w>>1/(RFCF) the sensing equation is: • The Clausius Mossotti factor at high frequencies, shows that a particle will only be trapped in the DEP cage if its permittivity is lower than the mediums giving rise to : • These two equations show the output voltage will decrease with particles at high frequencies

  17. Original Fabrication • No MEMS fabrication methods used • Printed Circuit Board (PCB) techniques used to attach electrodes • Silk screened the electrode pattern on to a gold clad board • etched away the uncovered portion • remove the screened resist Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  18. Similar DEP Devices • CMOS chip for individual cell manipulation • 102,400 actuation electrodes (20μm x 20μm) • Capability of manipulating 10,000 cells in parallel • Lack of integrated sensing technique Manaresi, N.; Romani, A.; Medoro, G.; Altomare, L.; Leonardi, A.; Tartagni, M.; Guerrieri, R. A CMOS Chip for Individual Cell Manipulation and Detection, IEEE Journal of Solid-State Circuits, 2003, 38, 12:2297-2305

  19. Similar DEP Devices • Dielectrophoretic Chip With a 3-D Electric Field Gradient • Asymmetric 3D electric gradient achieved with specially configured electrodes • Thick electrodes integrated into vertical wall structures, thin planar electrodes in bottom substrate • Enhanced vertical DEP force (lower voltages and temperatures) Iliescu, C.; Yu, L.; Xu, G.; Tay, F. A Dielectrophoretic Chip With a 3-D Electric Field Gradient, Journal of Microelectromechanical Systems, 2006, 15, 1506-1513

  20. Similar DEP Devices • MEMS electrostatic particle transportation system • Electrostatic device capable of transporting particles in air • Surface modifications performed to reduce adhesive forces Desai, A.; Lee, S-W.; Tai, Y. A MEMS Electrostatic Particle Transportation System. Sensors and Actuators, 1999, 73, 37-44

  21. Actuate the DEP Cage New parasitic DEP Cage (b) (a) Results Parasitic Cages • Parasitic Cages form between the two in-phase electrodes, electrodes 3 and 4 in Figure (a) • After actuating the DEP cage, a new parasitic cage will form capturing the slow moving particles Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  22. Parasitic Cages Results Parasitic Cages Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  23. (a) (b) (c) Results Parasitic Cages – Minimize effects Add intermediate step: • Creates a smaller chance slow moving particles will be trapped in the attraction basin of the parasitic cage Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  24. Results Parasitic Cages – Minimize effects Reduce space between electrodes: • Space between electrodes is nearly too small for particles to fit • Only possible using MEMS fabrication techniques due to small spacing Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  25. Results Modeling Assumptions • Cage distribution far too complicated to be modeled at the level of individual particles Assumptions • Particle cloud within the DEP cage can be modeled as homogenous • Permittivity and Conductivity depend solely on the ratio between the volume of microbeads and suspending medium in the cylinder (distilled water).

  26. Results Signal Processing Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325 • Fixed pattern noise (FPN) removed by subtracting initial non-cage reading (a) from cage reading, and then addition of average initial reading.

  27. Results Optical observation • Polystyrene microbeads, 3.46 µm diameter in H2O. • 10 Vpp, 100 kHz • 4 Concentration cycles • Raw data on left • Grayscale representation of data on right Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  28. Results Polystyrene Microbeads • Electric field simulation in FEMLAB in a 2-D plane • Simulation performed for initial concentration and 4 successive concentration cycles • Resistance translated to voltage output with known current Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  29. Results S. cerevisia • Experiment repeated with S. cerevisiae yeast cells in 280-mM mannitol. • Mannitol medium used to prevent overheating due to excessive conductivity • S. cerevisiae displays pDEP behavior above 200 kHz, electrolysis occurs at less than 30 kHz • Experiments performed at 100 kHz Medoro, G.; Manaresi, N.; Leonardi, A.; Altomare, L.; Tartagni, M.; Guerrieri, R. A Lab-on-a-Chip for Cell Detection and Manipulation. IEEE Sensors Journal, 2003, 3, 317-325

  30. Recommendations Micro-fabrication • Base layer of SiO2 with photoresist on Silicon

  31. Recommendations Micro-fabrication • Mask pattern, inverted from intended electrode pattern

  32. Recommendations Micro-fabrication • Exposure to light – removal of photoresist.

  33. Recommendations Micro-fabrication • Dry plasma etching – removal of Silicon Oxide

  34. Recommendations Micro-fabrication • Removal of photoresist with acetone

  35. Recommendations Micro-fabrication • Ion implantation of electrode channels

  36. Recommendations Micro-fabrication • Removal of silicon oxide via plasma etching with CF4

  37. Recommendations Micro-fabrication • Lap polish of wafer to 50μm thickness

  38. Recommendations Micro-fabrication • Growth of SiO2 layers, removal from underside.

  39. Recommendations Micro-fabrication • Spin deposition of photoresist and mask placement

  40. Recommendations Micro-fabrication • Exposure to light - removal of photoresist

  41. Recommendations Micro-fabrication • Dry plasma etching – removal of Silicon Oxide

  42. Recommendations Micro-fabrication • Removal of photoresist with acetone

  43. Recommendations Micro-fabrication • <110> wafer KOH through-etching of silicon wafer

  44. Recommendations Micro-fabrication • Removal of silicon oxide via plasma etching with CF4

  45. Recommendations Micro-fabrication • Combination of base electrode layer and reservoir layer

  46. Recommendations Micro-fabrication • Mated with wafer bonding over long electrodes, leaving wire-connection ports exposed

  47. Recommendations Micro-fabrication • Mass production on a silicon wafer • Glass cover with etched microchannel pattern and common reservoir

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