An equivalent electrical model for numerical analyses of ODEP manipulation

Abstract

Abstract-Opticaldielectrophoresis(ODEP)has been explored experimentally with success in manipulating microscale objects in the last 5 years. However, not much theoretical analyses have been performed to understand its operating principles in depth and also determine its limitations as a tool to manipulate micro-and nano-scale objects. In this paper, we present our work on establishing an equivalent electrical model to analyze the important physical interactions when optically induced dielectrophoretic force is used to manipulate micron-sized polystyrene beads. Simulation results show that the ODEP manipulation of microbeads is frequency-dependent and that the electrothermal effect is negligible. Furthermore, the relationship between the frequency of the applied voltage and the maximum manipulation velocity of the microbeads obtained from simulation is consistent with our experimental measurements. In addition, simulation results also show that the minimum radius of a bead that can be manipulated exponentially decreases with respect to the size of the illuminated spot. For instance, when the illuminated spot size is -indicating that ODEP can be extended to manipulate nano-scale objects if the illuminated spot size can be significantly reduced.

Simultaneous separation and concentration of micro- and nano-particles by optically induced electrokinetics

“…7(f). We note that some 1 m beads far from the optical pattern cannot be attracted and concentrated during the separation process, the reason of which is that the DEP force is proportional to the square of the gradient of the norm of the electric field and then sharply decreased for the 1 m beads existing far from the illuminated areas, as explained in our prior simulation work [28].…”

“…Furthermore, the calculated slip velocity was used as the boundary condition to solve the incompressible N-S equations for the ACEO flow distribution in liquid chamber. The simulation method for an ET flow is the same as those presented in our prior work as described in [28]. In addition, as noted in our prior work [28], the temperature increase due to the ET effect is ∼3 K, which is negligible.…”

“…The simulation method for an ET flow is the same as those presented in our prior work as described in [28]. In addition, as noted in our prior work [28], the temperature increase due to the ET effect is ∼3 K, which is negligible. Thus, we can use the average room temperature (i.e., T = 300 K) to calculate the Brownian motion.…”

“…The corresponding boundary conditions are the same as those discussed in our previous work [28]. Fig.…”

Optical Spectrum and Electric Field Waveform Dependent Optically-Induced Dielectrophoretic (ODEP) Micro-Manipulation

“…The time-harmonic analysis module, assuming Quasi-static current field with 2D axial symmetry, in Comsol was used to solve Maxwell's equations in the sub-domain of the liquid chamber of the ODEP chip. The simulation geometry and its corresponding boundary settings are the same as those discussed in our prior work in [27]. Figure 3 shows the simulation results for the purple, green, and red incident lights of a "ring" shape geometer.…”