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DEP Force Measurement on Polystyrene Beads and Red Blood Cells Using Optical Tweezers

Sasanpour Yazdi, Mehrzad | 2019

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 52559 (04)
  4. University: Sharif University of Technology
  5. Department: Physics Science
  6. Advisor(s): Seyed Reihani, Nader
  7. Abstract:
  8. In the presence of spatially non-uniform electric field, a dielectric object can experience a translational force which is known as Dielectrophoresis (DEP) force. DEP is one of the most applicable methods in sorting mechanism of different biological cells. Moreover accurately measuring the DEP force in single cell level can lead to a valuable knwoledge about the electrical properties of various cells.In this thesis, first, the other electrokinetic forces in which the Electro-Osmosis (EO) force is the important one, have to be eliminated. Regarding that this effect is strongly dependent on the frequency of external E field, we have applied the external electric field at appropriate frequency to remove this force. So the external applied DEP force on trapped Polystyrene (PS) beads has been measured using Optical Tweezers (OT). OT has the valuable potential in measuring the external force on trapped particles with 0.01fN accuracy. So, the experimental results show the reasonable physical behavior of DEP force on PS beads. Then considering that Red Blood Cells (RBCs) have the flexible and non-spherical structures in which the calibration parameters based on OT could not be accurate, we have introduced the new method for measuring the DEP force on these types of specimens. In fact, an external DEP force has been measured on trapped isolated PS bead and trapped bead in attachment with RBC. By subtracting these two forces, the DEP force on RBC has been estimated. Regarding that our new method shows the expectable DEP behavior on RBC (e.g. the DEP force behavior in terms of external squared voltage, the DEP force dependency on the axial distance from microelectrodes), it can be used on various cells with arbitrary shapes
  9. Keywords:
  10. Optical Tweezer ; Polystyrene ; Microparticles ; Red Blood Cell ; Dielectrophoresis Technique ; Electroosmotic Flow ; Microelectrode Array ; Electric Field External Frequency

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