An investigation of gelatin and other gels by electrokinetic methods

Abstract

The mechanism whereby particles appear, in micro-electrophoresis experiments, to move through firm gels has been investigated by electro-osmotic, streaming potential, and rigidity measurements. The study is concerned principally with gelatin gels, but agar, agarose and acrylamide gels have also been examined. It is shown that particles do not in fact move with respect to the gel network in firm gels. The apparent motion arises from the deformation of the gel network through the electro-osmotic build up of pressure. However, it is shown theoretically that the deformation mechanism gives the same distribution of particle velocity across the tube as would true electrophoresis in the ungelled system. Except possibly for very soft gels, the previously accepted view of a partial and reversible destruction of the gel network by an electric field is untenable. The observations at low temperature ( ≈ 0°C) require a different type of gelatin gel structure for their explanation.