Design of a Dielectrophoretic Mechanical Testing Device

Abstract

AbstractMechanics play a critical role in cell function in health and disease. While a variety of techniques exist to measure cell mechanics, no single device or testing method can answer all biomechanics questions. We have designed a novel dielectrophoretic cell mechanics device to apply piconewton forces to single, asymmetric attached cells without physical contact. This device uses negative dielectrophoresis to trap individual cells, after which cells attach to the device substrate. Negative dielectrophoresis is then used to apply compressive force to attached cells, and cell displacement is measured via microscopy.COMSOL software was used to model the two-dimensional electric and force fields. Based on modeling results, a quadrupole electrode configuration was designed in AutoCad,fabricated using microfabrication techniques, and tested with endothelial cells. A modeled quadrupole electrode with a 50 μm center diameter operating at 1 volt and 1 MHz generated 100's piconewtons of compressive force. This force was sufficient to trap both polystyrene beads and cells. While trapped cells did attach to the glass substrate, further refinement of the device is needed to maintain the cells in a healthy state.This dielectrophoretic mechanics testing device expands the existing biomechanics toolbox by providing a non-contact method to test mechanics of attached cells under diverse conditions. Future dielectrophoretic systems could allow tensile as well compressive forces, and when coupled with microfluidic systems, could test cell mechanics under fluid flow or a chemotactic gradient. This device will improve our understanding of cell mechanics in healthy cell function and how perturbation of the mechanical environment contributes to disease.