The Dielectrophoresis Network

at the University of Surrey


DEP of Nanoparticles

The dielectrophoretic manipulation of nanoparticles was long believed to be impossible.  Colloidal particles - typically found in a range of approximate y 1nm-1um, are small enough for Brownian motion to be the primary force on them, rather than gravity/bouyancy, but still too large to be dominated by intermolecular forces.  As such, and given that the DEP force scales with particle size, it was widely held that such particles would be too small for the force to overcome Brownian motion - something proven wrong in 1990 when Masao Washizu and colleagues first manipulated DNA.


The Surrey DEP group have over 20 years of experience (and publications) in this area, ranging from early work on  viruses (where Mike conducted the first separation of viruses, published in 1999 in Biophysical Journal) to over a decade on the theoretical basis of nanoparticle manipulation, and studies of the electrical properties of molecular structures from protins to carbon nanotubes and DNA.  


Fundamental concepts have been advanced on the movement of change in the electrical double layer and its contribution to the overall electrical behaviour of colloidal particles, and these have been used to understand the way in which charge moves through, and around, molecules such as CNTs and DNA. The group has also produced widley-cited reviews on the subject, particuarly the review paper "AC Electrokinetics: Applications in Nanotechnology" and the book "Nanoelectromechanics in Engineering and Biology"


The work overlaps sometimes into other areas, particularly the use of EHD-assisted aprticle focussing (see separate research section), and is currently being directed at the study of deposition techniques for ZnO nanowires for electronics applications.


Relevant papers in the journal archive:

6, 7, 10, 13, 14, 15, 17, 18, 19, 20, 21, 24,  34, 61, 65

Also see no. 1 in Books, and no. 1 in Book chapters.

pdep ndep