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Dielectrophoresis (DEP) is the name given to the induced movement of polarisable particles in non-uniform electric fields. First described analytically in 1951, it has been used since 1966 for the analysis of cells and other bioparticles. It relies on (typically) micromanufactured, planar electrodes in microfluidic systems, and has been applied to study and separate a wide range of cells and other bioparticles. As a discipline it has become widely adopted around the world, with typically 400 publications on the subject in an average year; however, it has never attained widespread adoption in the target biological community, but to the complexities of implementation and interpretation of results. We aim to remedy that through development both of instrumentation and applications.
Numbers in bold refer to the papers on the Publications page.
For more information on DEP, please visit the Dielectrophoresis Network page.
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2. DEP for diagnostics and cell biology
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3. Developing DEP at the nanoscale
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4. ACEO cell concentrators
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A related phenomenon to DEP is AC electro-osmosis (ACEO). This is the induced fluid motion at electrode surfaces, where highly inhomogeneous fields pass through the electrical double layer at a slight tangent to the orthogonal, inducing fluid movement. This phenomenon was first observed by Ron Pethig and co-workers who dubbed it “anomalous DEP”; it was later explained theoretically by Ramos and co-workers in the late 1990s.
We were the first to exploit the phenomenon, by using it for particle concentration on the surface of biosensors (26,28,30,31). The nature of ACEO is that the effect is (as we showed) independent of size (47); particles are trapped at the same rate whether they are molecules, viruses, bacteria or cancer cells. The phenomenon was developed in a project funded by DSTL and was subject to three patent applications (30,31,55), until the 2008 financial crisis ended DSTL’s commercialisation work.
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Since then the phenomenon has been explored further, including incorporation into QCM biosensors for nanoparticle detection (45), continuous separation from liquid flow (69), and an optimisation study (68). It currently forms the basis of a number of ongoing company-funded projects in the lab (not published for commercial reasons).
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"Begin with the possible and gradually move towards the impossible"
- Robert Fripp, guitarist