Numerical simulation of long-range cell manipulation with AC electrokinetics by immersed boundary-lattice Boltzmann method

Alternating current (AC) electrokinetics have been widely used to manipulate bioparticles such as mammalian cell, bacteria, DNA, and protein among which the efficient cell patterning is essential for several biomedical and tissue engineering applications. Dielectrophoresis (DEP) is a well-known phenomenon that a force acts on the polarized particle in the non-uniform electric field, and it has been demonstrated as an effective, noninvasive, and non-destructive technique for cell trapping and separation. However, DEP force reduces dramatically with the decrease of electric field gradients which makes it ineffective for controlling the motion of cell in the region far away from the electrode edges. Fortunately, AC electrothermal (ACET) flow occurs when there exists electric field and temperature gradient caused by Joule heating or other external heat sources. The driving mechanism of ACET flow makes it important for pumping the physiological media of high conductivity under which circumstance the AC electroosmosis flow is weak. The drag force induced by ACET flow on the cell could transport it into the region near the electrode where the negative DEP force is significant. By balancing the DEP force, the drag force, and the gravitational force, the cell could be successfully suspended in the solution which is useful for cell patterning or other biomedical operations. In the current work, the immersed boundary-lattice Boltzmann method (IB-LBM) with GPU acceleration on a CUDA computational platform is used to accurately simulate the motion of cell under hybrid AC electrokinetic phenomena. The results indicate that a single cell could be successfully suspended at an equilibrium position due to the balanced ACET electrohydrodynamic force, negative DEP force, and gravitational force. However, the double cells confront a periodic motion around each other when the DEP force is not sufficient to overcome the effects of ACET flow and cell-cell interaction.