title: Capillary electrophoresis of DNA in uncrosslinked polymer solutions: evidence for a new mechanism of DNA separation.
abstract: The electrophoretic separation of DNA molecules is usually performed in thin slabs of agarose or polyacrylamide gel. However, DNA separations can be achieved more rapidly and efficiently within a microbore fused silica capillary filled with an uncrosslinked polymer solution. An early assumption was that the mechanism of DNA separation in polymer solution-capillary electrophoresis (PS-CE) is the same as that postulated to occur in slab gel electrophoresis, i.e., that entangled polymer chains form a network of "pores" through which the DNA migrates. However, we have demonstrated that large DNA restriction fragments (2.0-23.1 kbp) can be separated by CE in extremely dilute polymer solutions, which contain as little as 6 parts per million [0.0006% (w/w)] of uncrosslinked hydroxyethyl cellulose (HEC) polymers. In such extremely dilute HEC solutions, far below the measured polymer entanglement threshold concentration, pore-based models of DNA electrophoresis do not apply. We propose a transient entanglement coupling mechanism for the electrophoretic separation of DNA in uncrosslinked polymer solutions, which is based on physical polymer/DNA interactions.
authors.affiliation: Department of Chemical Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Barron
authors.forename: W M
authors.initials: WM
authors.lastname: Sunada
authors.forename: H W
authors.initials: HW
authors.lastname: Blanch