Nonequilibrium separation of short DNA using nanoslit arrays

Abstract

A nonequilibrium regime of size-based separation was observed experimentally for double-stranded deoxyribonucleic acid (DNA) molecules with lengths below 1 kbp moving electrokinetically through nanofluidic nanoslit arrays. The breakdown of Ogston sieving was supplanted at higher electric fields to recover rapid separation with a reversed elution order and elution times one to two orders of magnitude faster than with Ogston sieving at lower fields. A simple kinetic model describes the experimental results.

Figure 1

Top-down schematics of nanoslit array (A and B) and individual nanoslit (C and D) device geometries with side-view schematics (not to scale).

Figure 2

(a) Electropherograms of 55 and 259 bp DNA taken in nanoslit array device B. Elution order changed with increasing values of E_ave. μ for 259 bp DNA (open squares) and 753 bp DNA (closed triangles) is normalized by μ_{55 bp} for each elution and plotted against E_ave for geometries A (b) and B (c). Theoretical fits to the data are shown for 259 bp (dotted line) and 753 bp DNA (solid line). Errors of one standard deviation are smaller than the data symbols.

Figure 3

(a) Electropherograms of 55 and 259 bp DNA taken in nanofluidic device C. Elution order did not change for all investigated values of E_ave. μ for 259 bp DNA (open squares) and 753 bp DNA (closed triangles) is normalized by μ_{55 bp} for each elution and plotted against E_ave for geometries C (b) and D (c). Errors are one standard deviation and where not visible are smaller than the data symbol. Errors are larger for (b) than for (c), Fig. 2b, or Fig. 2c, due to shorter elution times.