Sub-micrometre AC electrokinetics

AC electrokinetics is a general term which refers to a range of techniques for which electric fields are used to study and manipulate particles, particularly bioparticles, and fluids. It has proved successful in the characterisation of cells and bacteria as well as the separation of particle types. Recent application of this technique to the sub-micrometre range (viruses, DNA and proteins) has opened up a new field of research in bioparticle diagnostics. This paper discusses AC electrokinetic techniques such as dielectrophoresis (DEP), electrorotation and travelling-wave dielectrophoresis, and in particular the application of DEP in the colloidal domain. Results of the dielectrophoretic properties of spherical latex particles and tobacco mosaic virus are presented. The use of electric fields to control the movement of fluids and particles is also discussed.