Preparative electrophoresis

The principle of electrophoresis, the migration of charged substances under the influence of a continuous electric field, was described a century ago by Kohlrausch. It wasn't until 1937 that Tiselius demonstrated the usefulness of the moving-boundary method for separating proteins from blood serum. Today, electrophoresis has become the most widely used analytical method in biology, thanks to its performance and relative ease of use. Along with chromatography, it has contributed to major advances in biochemistry and biotechnology, enabling the detection and analysis of the various constituents of a complex biological medium. Where Tiselius separated 5 constituents, more than 1,000 can now be identified by two-dimensional gel electrophoresis.

This considerable progress has been achieved thanks to both experimental and theoretical scientific advances, as well as increasingly sophisticated instrumentation.

Theories on electrophoretic mobility, migration and electrolyte dissociation have been extended to all types of electrophoresis (zone electrophoresis, isoelectric focusing, isotachophoresis...). They can be used to simulate product displacement. The dispersive effects inherent in any separation process have been better understood and taken into account in the transport equations. An important effect, electrohydrodynamics, has even been recently discovered.

On the experimental front, increasingly high-performance materials, used to form gels or coat the walls of electrophoresis chambers, have made it possible to limit adsorption and electro-osmosis, and improve their lifetime. New methods have been proposed for product characterization, desorption and collection. New processes have been designed and developed, such as capillary electrophoresis, which is currently enjoying a boom.

Electrophoresis is a high-performance analysis method, and so it naturally attracted interest as a preparative method. How can we go from analyzing a few nanograms or micrograms to producing a few milligrams, or even grams, while maintaining the same finesse of separation? To provide answers to this question, researchers have tried to extrapolate and improve existing processes in the analytical field, or to develop new techniques more specifically adapted to the preparative field.