On the limiting pore size of hydrophilic gels for electrophoresis and isoelectric focusing.

The maximum pore diameter that can be obtained in hydrophilic gels, either highly diluted agarose (0.16%C) or highly cross-linked polyacrylamide (45%CBis or 60%C DHEBA) is around 500 nm. An empirical equation has been derived linking the mean pore diameter (mean p) to gel concentration (C) in dilute agarose gels: mean p = 140.7 x C(-0.7). It is suggested that other equations hold for concentrated gels and for highly cross-linked polyacrylamides, since the matrix structure is different. Most of the cross linkers for polymerizing polyacrylamide gels have been tabulated and their properties studied. A new gel matrix is described: a highly cross-linked N,N'-(1,2-dihydroxyethylene)bisacrylamide gel, which is hydrophilic, highly porous and can be conveniently used for electrophoresis in horizontal, ultrathin layers cast on silanized glass surfaces.