Bioparticle delivery in physiological conductivity solution using AC electrokinetic micropump with castellated electrodes

Alternating current (AC) electrokinetics have many applications in engineering fields, among which the efficient delivery of bioparticles in a continuous flow is significant for further biomedical manipulations. To avoid the cell lyse caused by low electrical conductivity environment, the AC electrothermal (ACET) phenomenon which effectively drives the physiological fluid with high electrical conductivity becomes attractive. In addition, negative dielectrophoresis (nDEP) is usually induced on the polarized bioparticles immersed in physiological fluid with a non-uniform electric field. In the current work, a novel AC electrokinetic micro-device with castellated electrodes is designed for delivering bioparticles in high electrical conductivity fluid without the use of a mechanical micropump. The ACET flow vortex could be eliminated by replacing the interdigitated electrodes with the castellated electrodes. Besides, by appropriately choosing the phases of AC voltages, a nDEP force is induced to repel the bioparticles from the electrode edges and the microchannel surfaces. Under this circumstance, the bioparticle transport efficiency is highly improved, and the cell adhension on the micropump surfaces is also reduced. The effects of AC voltage magnitudes, electrical conductivities of solution and bioparticles, bioparticle size, and bioparticle initial position on the multi-physical bioparticle transport process are investigated by immersed boundary-lattice Boltzmann method. The results demonstrate that the hybrid AC electrokinetics using castellated electrodes is an efficient technique of delivering bioparticles in a lab-on-a-chip device.