MEASUREMENT OF DIELECTRIC PROPERTIES OF MICROALGAE WITH DIFFERENT LIPID CONTENT USING ELECTROROTATION AND NEGATIVE DIELECTROPHORESIS CELL TRAP

This paper presents a precise measurement of dielectric properties of cells, especially microalgae having different intracellular lipid content by using a combination of electrorotation (ROT) and negative dielectrophoresis (nDEP) force-based cell trapping method. To achieve this, eight electrode pairs were built within a microchannel, sharing the same geometrical center. A single microalgal cell was trapped and levitated in the center by nDEP force generated from four electrode pairs, while simultaneously ROT torque was generated from the other four pairs to rotate the trapped cell. This method allows conducting ROT measurement at up to similar to 100 MHz on a single trapped cell. As a result, both the cytoplasm conductivity and permittivity that depends on intracellular lipid content differences could be accurately analyzed based on the rotation speed of the cell.