Focusing proteins in an electric field gradient

Gradient techniques are a class of separation methods that combine the steps of isolation and concentration. This class of techniques uses one or more gradients of counteracting forces to create an 'equilibrium point' at which a protein can focus. Equilibrium gradient techniques can be adapted to a specific separation by choosing appropriate counteracting forces based on differences in the physical characteristics of proteins. The method introduced here, field gradient focusing, is an addition to this class of separation techniques which employs a gradient in the electric field to simultaneously separate and concentrate molecules.