Annelise E. Barron
Publication Details
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Capillary electrophoresis of DNA in uncrosslinked polymer solutions: evidence for a new mechanism of DNA separation.
Biotechnol Bioeng. 1996; (2): 259-70
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.
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