Effects of Cell Shape On Electrokinetic Immobilization Efficiency In Insulator-Based Dielectrophoretic Devices

Dielectrophoresis (DEP) is defined as the motion of a dielectric particle due to a force as a result from the polarization of the particle in the presence of a non-uniform electric field. DEP has been proven as an efficient electrokinetic technique for the manipulation of particles in microfluidic systems. Early designs of microfluidic devices employed metallic electrodes on the surfaces of the substrate in the device to create the non-uniform electric fields. Metallic electrodes presented several disadvantages considering high costs, complex elaboration, limited life time, etc. An alternative to create non-uniform electric fields is the use of insulating structures along the microdevice between two electrodes in order to bend the electric field between them. This approach is known as insulator-based dielectrophoresis (iDEP). In the present work, the performance of an iDEP microdevice is evaluated employing bioparticles with different geometry shape and size. A computational model is developed to predict and estimate the theoretical trapping zones in the microdevice due to negative DEP response from the particles to evaluate. Saccharomyces cerevisiae cells with a spherical shape and Escherichia coli cells with a prolate ellipsoidal shape are employed in this work. Experimental and theoretical results are compared in the present study.