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Updated: Aug 15, 2026

Label-free Isolation and Enrichment of Cells Through Contactless Dielectrophoresis
Published on: September 3, 2013
Superpositioned dielectrophoresis for enhanced trapping efficiency
Fredrik Aldaeus1, Yuan Lin, Johan Roeraade
1Department of Chemistry, Analytical Chemistry, Royal Institute of Technology (KTH), Stockholm, Sweden.
Abstract:
One of the major applications for dielectrophoresis is selective trapping and fractionation of particles. If the surrounding medium is of low conductivity, the trapping force is high, but if the conductivity increases, the attraction decreases and may even become negative. However, high-conductivity media are essential when working with biological material such as living cells. In this paper, some basic calculations have been performed, and a model has been developed which employs both positive and negative dielectrophoresis in a channel with interdigitated electrodes. The finite element method was utilized to predict the trajectories of Escherichia coli bacteria in the superpositioned electrical fields. It is shown that a drastic improvement of trapping efficiency can be obtained in this way, when a high conductivity medium is employed.
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