This was a first work, where Biological Dynamic's founders were able to demonstrate possibility of isolation of nanoparticles from a high conductivity solution using hydrogel over-coated microelectrodes.
Krishnan, R., Dehlinger, D.A., Gemmen, G.J., Mifflin, R.L., Esener, S.C., and Heller, M.J. (2009), Interaction of nanoparticles at the DEP microelectrode interface under high conductance conditions. Electrochem commun., 11: 1661–1666. doi: 10.1016/j.elecom.2009.06.033
The separation of nanoparticles from micron size particles in high conductance buffers was achieved using an AC dielectrophoretic (DEP) microarray device with hydrogel over-coated microelectrodes. While nanoparticles could be selectively concentrated into high field regions directly over the platinum microelectrodes, micro-bubbling and electrode darkening was also observed. For similar experiments using un-coated microelectrodes, SEM analysis showed severe erosion of the platinum microelectrodes and fusion of nanoparticles due to the aggressive electrochemistry.