Accumulation and filtering of nanoparticles in microchannels using electrohydrodynamically induced vortical flows

Research output: Contribution to journalResearch articleContributedpeer-review



We present an approach for the accumulation and filtering of nano- and microparticles in microfluidic devices that is based on the generation of electric traveling waves in the radio-frequency range. Upon application of the electric field via a microelectrode array, complex particle trajectories and particle accumulation are observed in well-defined regions in a microchannel. Through the quantitative mapping of the 3-D flow pattern using two-focus fluorescence cross-correlation spectroscopy, two vortices could be identified as one of the sources of the force field that induces the formation of particle clouds. Dielectrophoretic forces that directly act on the particles are the second source of the force field. A thorough 2-D finite element analysis identifies the electric traveling wave mechanism as the cause for the unexpected flow behavior observed. Based on these findings, strategies are discussed, first, for avoiding the vortices to optimize electrohydrodynamic micropumps and, secondly, for utilizing the vortices in the development of microdevices for efficient particle accumulation, separation, and filtering. Such devices may find numerous biomedical applications when highly diluted nano- and microsuspensions have to be processed.


Original languageEnglish
Pages (from-to)2987-2996
Number of pages10
JournalElectrophoresis : electrokinetics, fluidics, proteomics
Issue number14
Publication statusPublished - Jul 2008

External IDs

PubMed 18655037



  • Dielectrophoresis, Fluorescence correlation spectroscopy, Lab-on-chip, Micro fluidics, Traveling electric waves