A micromachined electrical field-flow fractionation (/spl mu/-EFFF) system

Micromachining technologies are employed to develop a miniaturized electrical field-flow fractionation (EFFF) separation system. EFFF systems are used to separate colloidal particles such as cells, liposomes, proteins, or other particulates, and to characterize emulsions and other mixtures according to particle charge density. Macromachining techniques have been used to develop existing EFFF technologies. At the present time, the limiting factor in the development of higher precision EFFF separation systems has been the manufacturing approach. In this paper, the theory behind the operation and resolution of a micron-sized EFFF (μ-EFFF) system is described and the advantages to be gained from application of micromachining technologies are given, thus motivating the need for further miniaturization. A completely fabricated μ-EFFF system is developed, separations are performed, and the μ-EFFF system is compared to the theoretically predicted results as well as the results from current macro EFFF systems.