Electrophoretic separation of large DNAs using steric confinement

TL;DR

This paper introduces a novel electrophoretic separation method for large DNA molecules using steric confinement between solid walls, eliminating the need for gels or obstacles, and investigates mobility changes with confinement thickness.

Contribution

It presents a new gel-free separation technique based on steric confinement and analyzes the mobility transition at specific confinement scales.

Findings

Separation occurs at small confinement thicknesses.

Mobility transition to bulk behavior at about 4 μm confinement.

Observed separation without traditional gels or obstacles.

Abstract

We report an alternative method for electrophoretic separation of large DNAs using steric confinement between solid walls, without gel or obstacles. The change of electrophoretic mobility vs confinement thickness is investigated using fluorescence video microscopy. We observe separation at small confinement thicknesses followed by a transition to the bulk behaviour (no separation) at a thickness of about 4 μm (a few radii of gyration for the studied DNA chains). We present tentative explanations of our original observations.