Dielectrophoretic properties of submicron diamond particles in sodium chloride aqueous solution

Dielectrophoretic (DEP) manipulation of a diamond particle has potential application in the detection of DNA or other bio-molecules. We investigate the fundamental DEP and surface properties of submicron diamond particles. Diamond particles were dispersed in a NaCl solution and dropped on a castle-walled electrode. An AC electric field was applied to determine the DEP crossover frequency as a function of the solution conductivity. The surface conductance of the diamond particles was then evaluated from the parametrical fitting of the crossover frequencies. The diamond surface layer was shown to exhibit a rather high conductance, although bulk diamond is insulative.