Single Molecule Observation of DNA Electrophoresis in Pluronic F127

Abstract

Single molecule fluorescence microscopy is used to follow the motion of long DNA molecules undergoing electrophoresis in Pluronic gels. We find that for low fields most DNA molecules follow tortuous paths through the gels, at an angle up to 90 degrees from the field direction, while some molecules find paths along the field lines. In high fields, virtually all of the DNA molecules follow the field lines. In many cases, the molecules travel as compact coils with optically discernible radii smaller than in free solution. In other cases, the molecules extend and contract or travel in an extended configuration.