Comparative evaluation of electrode configuration for optimizing positive dielectrophoresis trapping of CCRF-CEM cells.

Abstract

Dielectrophoresis (DEP) is a promising label-free technique for bioparticle manipulation, offering significant potential for diagnostic application such as isolation and trapping of cancerous CCRF-CEM cells. The efficacy of DEP trapping is critically dependent on the interaction between the cell's dielectric properties and the spatial gradient of the squared electric field (∇|E²|), which is governed by electrode geometry. This study conducts a comparative evaluation, via finite element method (FEM) analysis, to quantify the positive dielectrophoresis (pDEP) force exerted on CCRF-CEM cells. Four distinct electrode configurations were analyzed: parallel (rectangular, triangular, cylindrical) and interdigitated. Based on a single-shell model for CCRF-CEM cells within a low-conductivity buffer, the Clausius-Mossotti factor was determined at 4.6 MHz, confirming a strong pDEP response that attracts cells to high-field regions. Results demonstrate that the pDEP force scales quadratically with applied voltage and is significantly enhanced by reducing the electrode gap. At a standardized 25 Vpp and 100 μm gap, the interdigitated configuration generated the highest maximum pDEP force, substantially exceeding the parallel rectangular, triangular, and cylindrical designs. Furthermore, the interdigitated geometry produced the most extensive and uniform high-force zones along the electrode edges, creating a superior trapping area. This comparative evaluation provides quantitative guidelines for optimizing electrode design, identifying the interdigitated configuration as the most effective for developing high-efficiency microdevices for CCRF-CEM cell trapping.