A Low-Voltage Dielectrophoretic System Using Thread Based Electrodes for Cell Viability Assessment

Abstract

We present a disposable low-voltage thread-based electrode system that can differentiate live and dead Saccharomyces cerevisiae cells via field-induced assembly. Our system consists of a silver nanoparticle based conductive thread electrodes embedded in a rubber o-ring. The three-dimensional conductive thread with high aspect ratios were found to facilitate high electric field regions at low voltages. Rapid assembly of biological cells into highly ordered pearl chains was observed at voltages as low as 4V.Thread based devices create DEP forces that are larger by two orders of magnitude for the same applied voltage when compared to most microfluidic e-DEP designs in literature, which rely on planar electrodes to produce the DEP forces. Numerical simulations of electric field intensity in the device using a representative thread geometry also confirmed our experimental findings. The dead cells probed at a voltage of 4V @2.5 MHz was found to aggregate in low electric field regions. The percentage of live and dead cells are estimated using an image recognition algorithm that analyze cells that are viable in a given sample within 60 seconds. The area occupied by the dead-cell aggregate is a direct indicator of cell viability.We are currently exploring the possibilities of three-dimensional assembly of microparticles for point-of-care applications. Figure 1