What are the theories about strawberry jelly as a substitute to agarose?
Tiselius developed an early electrophoretic apparatus which involved a moving boundary technique for the separation of substances by electrophoretic means. A technique, coupled with his investigations into absorption analysis, which earned him the Nobel prize in 1948. With the knowledge of what Tiselius’ apparatus was able to produce, a group of scientists recognized its inability to offer discrete molecular visualisation. Gordon, Consden and Martin endeavoured to apply silica jelly as a matrix for the complete separation of amino acids and peptides through a method of ionophoresis (the movement of charged particles in a colloid whilst under the influence of an electric field). Gordon et al suggested the employment of a rectangular piece of silica jelly that was bathed in electrolyte to overcome a problem they observed with the Tiselius apparatus. They reported that without the compartment of diaphragms, a convection of electrolyte under an electrical field would be prevented. They commented that “the density gradient is provided by the substances under investigation” and so without said density gradient, “complete separation into separate bands cannot be obtained”. They noted that the purpose of the swamping of silica jelly in the electrolyte was to ensure that “the substances being analysed can move independently and separate into discrete bands”.
Maniatis, Fritsch, Sambrook and Engel and Rickwood and Hames have since developed this concept, and agarose gel is now regarded as the standard matrix used for the separation and purification of DNA and RNA fragments (in horizontal format).
Traditionally, agarose gels are run in a horizontal format, lying directly in a buffer as ‘submarine’ gels for the separation of nucleic acids.