Applications of Polyelectrolyte Migration

Figure 1: Trapping of DNA near the inlet of a microfluidic device. A. Epifluorescent images at the device inlet (green) and outlet (blue); circles indicate the positions of individual DNA molecules. The centerline fluid velocity is 1200 micron/second, while the opposing electrophoretic velocity is 50 micron/second. B. Schematic of the device showing the direction of flow (blue) and electrophoresis (green); the diagram is not entirely to scale. C. A confocal scan showing the three-dimensional distribution of DNA within a 40 micron slab located on the lower wall of the inlet. DNA (orange) is concentrated on the wall of the device. D. A perspective sketch of the inlet region, indicating the distribution of trapped DNA. The experiments were made by Mert Arca.

Accumulation of DNA at the inlet of the micronfluidic device.

Separation of DNA from charged microfluidic spheres of similar size and mobility. The rigid spheres do not migrate and so pass through the device unhindered.


  1. M. Arca, A. J. C. Ladd, and J. E. Butler. Soft Matter, 12:6975-6984, 2016.


Jason Butler

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