Theory of Capillary Electrophoretic Separation of DNA Using Ultradilute Polymer Solutions

Abstract

We present a model of DNA electrophoresis in unentangled polymer solutions based on a new separation mechanism in which the DNA drags along polymer molecules it encounters during migration. Taking into account the deformation and the hydrodynamic resistance of the polymers in the flow, the mutual disengagement time of the DNA and the polymer, and the average number of polymers dragged by one DNA, we build a self-consistent theory leading to predictions for the DNA velocity as a function of the experimental conditions. Our results agree with the data of Barron et al. (1994), and important separation regimes are also identified.

Separation of double-stranded and single-stranded DNA in polymer solutions: I. Mobility and separation mechanism

“…In contrast to gels, often the whole conformation is then seen to move downfield. This behavior has some similarity to the ªen-tanglement couplingº process, which has been studied both experimentally and theoretically in dilute solutions [2,30]. However, to date there is no theoretical treatment of the combination or reptative movement and polymer dragging, which might describe the DNA movement in entangled polymer solutions.…”

Theory of DNA electrophoresis (∼ 1999 –2002 ½)

“…In this picture the DNA undergoes collisions with the neutral polymers; the average number of polymers that the DNA is dragging along at any given time is dependent on the molecular weight of the DNA and hence separation is achievable. The theory of Hubert et al [118] indicated that this mechanism can quantitatively account for the observed electrophoretic motion, although their model was limited to dilute solutions of small polymers. Recent experimental results from Ekani Nkodo et al [116,117] on the electrophoresis of l-DNA in dilute solutions of dextran call into question this general "collision" mechanism for the dilute regime.…”

“…Several computational [119][120][121][122][123] and theoretical [118,124] investigations are also beginning to shed some light on the mechanisms involved in electrophoretic separa-tions in dilute polymer solutions. Noguchi et al [122] have carried out BD simulations of a polyelectrolyte chain in the presence of an external field.…”

Electrohydrodynamically induced aggregation during constant and pulsed field capillary electrophoresis of DNA

“…However, the separation range can be increased up to approximately 23 kbp using very dilute polymer solutions (c Ͻ c*). 18,19 The time to complete the analysis in such solutions is short, but the resolution is generally poorer compared to the one obtained in entangled solutions. Pulsed Fields can be applied in CE, using the "field inversion" mode, in which unequal forward and backward pulses are alternated (for a review, see Ref.…”