Free Flow Electrophoresis as a Purification Step of High Versatility for Bioproducts

Abstract

AbstractElectrophoresis in general separates particles or molecules according to their specific mobility in an electric field. The mobility is a function of the net charge of the particle or the molecule, as well as of its size and the viscosity of the carrier. Unlike conventional gel electrophoresis (e.g. PAGE) free flow electrophoresis (FFE) continuously separates the components of a sample in ordinary buffer liquids. Thus in the case of FFE the net charge becomes the most important parameter. FFE devices are designed in a way that the influences of disturbing phenomena (e.g. electroosmosis, free convection, or adsorption), which lower the quality of the separation, are minimized. — Two FFE devices (ELPHOR VaP 22; BIOSTREAM) have been tested using a monoclonal antibody (IgG) and bovine serum albumin (BSA) as model substances. The aim of the tests was to determine the applicability of FFE to medium and large scale protein purification. — Compared to other purification methods (i.e. ion exchange) the costs of a FFE step in downstream processing are high. Thus the use of FFE in fields other than research may be limited to products of high value, where chromatography fails. There free flow electrophoresis may exhibit its specific advantages in the purification of fluids containing particles such as cell debris or organelles, or even in the separation of viable cells.