Set-up for an Optically Induced Dielectrophoresis Platform and Its Use in Manipulating Micro- and Nanoscale Materials

An optically-induced dielectrophoresis platform is proposed to manipulate micro- and nanoscale particles. A commercially available liquid-crystal-display-based projector was used as a light source to produce a variety of optical patterns and project them onto a photoconductive material. The optical patterns illuminating the photoconductive material can be used as configurable virtual electrodes, which will induce dielectrophoretic forces on the particles which can thus be manipulated by dynamic optical patterns. The manipulation of silver nanowires was demonstrated by forming a specific pattern of nanowires through illumination of the photoconductive chip with an optical pattern. Polystyrene beads with diameters of 10 and 20 μm were also successfully manipulated. By combining the optically-induced dielectrophoretic force and the hydrodynamic force, particles of two different sizes can be continuously separated into two different microchannels. Furthermore, the microparticles were collected and concentrated by virtual electrode traps. We believe that this flexible platform can be applied to a variety of fields such as single cell study, nanotechnology, or surface-enhanced Raman spectroscopy.