2D dielectrophoretic signature of Coscinodiscus wailesii algae in non-uniform electric fields

This paper investigates the 2D dielectrophoretic signature of a unicellular centric green alga, Coscinodiscus wailesii, in non-uniform electric fields. The electrokinetic response was studied as a function of applied signal frequency and voltage. The effective permittivity of the diatoms was studied through mathematical simulation resulting in analyzing the diatoms' frequency response. Three different types of dielectrophoretic responses were measured and analyzed (i) lateral displacement of cells, movement of diatoms in a particular direction based on their dielectric polarizability, (ii) dielectrophoretic force, the translational force experienced by the diatoms as a result of applied non-uniform electric fields and (iii) translational dielectrophoretic velocity, the speed at which the diatoms move either towards or away from strong electric fields. The approaches discussed in this paper will improve the predictability of the dielectric properties of the diatoms using a combination of these parameters. The calibration of the physical diatom model to the experimental data results in the estimation of their dielectrophoretic behavior depending on the geometric structure of the diatom model. This method offers a practical means of label-free manipulation of diatoms and for rapid screening for environmental effects on the dielectric properties of algal cells.