Radial migration of DNA molecules in cylindrical flow. III. Circles and the effect of non-gaussian polymer statistics.

We have previously shown that DNA will migrate radially inward in a concentric-cylinder shear flow apparatus. We assumed gaussian chain statistics, and we considered only linear molecules. In this paper, we extend the analysis to closed circular molecules, and we consider non-gaussian statistics for both linears and circles. We find that, in good solvents, the inward radial migration velocity is more sensitive to the molecular weight than M5/2, which we previously reported for gaussian chains. Furthermore, linears migrate radially inward 8 times faster than do circles of the same molecular weight. This suggests the possibility of separating linear from circular DNA in solution.