Separation of Large DNA Molecules by Contour-Clamped Homogeneous Electric Fields

TLDR

Electric fields can be shaped by arranging multiple electrodes along a closed contour and clamping them to fixed potentials. The method is intended for broad applications in macromolecule separation by gel electrophoresis. Using contour‑clamped electric fields, DNA up to 2 Mb can be cleanly separated with alternating 120° orientations, the pattern is position‑independent, and smaller fragments (<50 kb) separate without distortion at high voltage, while sub‑200‑base bands broaden less with inhomogeneous fields.

Abstract

Electric fields can be manipulated by a method in which multiple electrodes are arranged along a closed contour and clamped to predetermined electric potentials. This method may be applied to a broad range of problems in the separation of macromolecules by gel electrophoresis. DNA molecules as large as 2 megabases can be well separated with a contour-clamped homogeneous electric field alternating between two orientations 120° apart. The pattern of separation is independent of position in the gel, which is an advantage over previous methods. DNA less than 50 kilobases can be separated without distortion even at high voltage with a nonalternating contour-clamped homogeneous field. Decreased band broadening in DNA less than 200 bases can be achieved with a contour-clamped inhomogeneous field.