Holding Forces of Single-Particle Dielectrophoretic Traps

Abstract

We present experimental results and modeling on the efficacy of dielectrophoresis-based single-particle traps. Dielectrophoretic forces, caused by the interaction of nonuniform electric fields with objects, have been used to make planar quadrupole traps that can trap single beads. A simple experimental protocol was then used to measure how well the traps could hold beads against destabilizing fluid flows. These were compared with predictions from modeling and found to be in close agreement, allowing the determination of sub-piconewton forces. This not only validates our ability to model dielectrophoretic forces in these traps but also gives insight into the physical behavior of particles in dielectrophoresis-based traps. Anomalous frequency effects, not explainable by dielectrophoretic forces alone, were also encountered and attributed to electrohydrodynamic flows. Such knowledge can now be used to design traps for cell-based applications.

Microfluidic electromanipulation with capacitive detection for the mechanical analysis of cells

“…22 The values of these parameters for polystyrene and yeast [23][24][25][26] are given in Tables I and II. Figures 7 and 8 show the capacitance change as a function of particle position for yeast cells and polystyrene spheres.…”

Electrodeless direct current dielectrophoresis using reconfigurable field‐shaping oil barriers

“…The net electric force on a spherical dielectric particle within a static electric field E is given [34] by…”

“…e p ,e m ), the particles get repelled away from the highest field gradients due to n-DEP forces. Often the electrodes are designed such that the particles repelled from the electrode edges accumulate at the interelectrode gap [33,34]. Charged particulate matter like DNA, proteins, and some types of cells exhibit p-DEP when they are suspended in solutions of low conductivity [2,12,19,35].…”

Designing a nano-interface in a microfluidic chip to probe living cells: Challenges and perspectives

“…Dielectrophoretic technology has also aided in the detection of cellular responses to toxicants (48) and in the concentration of various cell suspensions, including bacteria (49) and viruses (50). Nonlinear electrokinetics has also been used to achieve particle levitation (51), alignment for the electrofusion of cells (52,53), electroporation for the inclusion of molecules into cells (27,54), and fabrication of dielectrophoretic field cages to trap single cells (55,56). Micropatterned metal electrodes are typically used to create the nonuniform electric fields; however, carefully positioned insulated posts can achieve the same effect (57,58).…”