ABSTRACT
Researchers in the biophysical sciences have been concerned with the rapid and gentle isolation of macromolecules of all sizes and types. Although the exact dates of early thoughts on the subject are difficult to place, records from Discussions of the Faraday Society in 1949 (1) reflect on both speculation and evidence that porous media may be useful in separating biomolecules by size. The chronology of the subsequent discovery of the particle-sieving effects of starch and crosslinked dextran gels in the 1950s at the Institute of Biochemistry, University of Uppsala, Sweden, is well reviewed in a recent article by Hagel and Janson (2). The separation and collection of many water-soluble biopolymers has since been possible using the principle first called gel filtration. Sephadex® (Pharmacia, Uppsala, Sweden) was the first commercial separation media made from water zv440 insoluble crosslinked polydextran gel and was originally described by Porath and Flodin in 1959 (3). Soon after this initial breakthrough, Granath and Flodin clearly demonstrated the relationship between the elution of fractionated dextrans and proteins and some function of the molecular size of the solute (4). In fact, the early work showed a tendency for elution in reverse order of molecular weight. This observation then stimulated interest in finding a simple relationship between the absolute molecular weights of macromolecules and their elution volumes in the hope that such a relationship might be useful as a predictive analytical tool for unknown systems. The early uses of Sephadex® were broadly reviewed by Porath (5) in 1967; however, the popularity of these packing materials diminished with the availability of stronger, more efficient preparations.
