title: Noise-enhanced gel electrophoresis.
abstract: Macromolecules confined within a nanoporous matrix experience entropic trapping when their dimensions approach the average pore size, leading to emergence of anomalous transport behavior that can be beneficial in separation applications. But the ability to exploit these effects in practical settings (e.g., electrophoretic separation of DNA) has been hindered by additional dispersion introduced as a consequence of the uncorrelated process by which the embedded macromolecules discretely hop from pore to pore. Here, we show how both the source and solution to these difficulties are intimately linked to the inherent dynamics of the underlying activated transport mechanism. By modulating the applied electric field at a frequency tuned to the characteristic activation timescale, a resonance condition can be established that synergistically combines accelerated mobility and reduced diffusion. This resonance effect can be precisely manipulated by adjusting the magnitude and period of the driving electric field, enabling enhanced separation performance and bi-directional transport of different-sized species to be achieved. Notably, these phenomena are readily accessible in ordinary hydrogels (as opposed to idealized nanomachined topologies) suggesting broad potential to apply them in a host of useful settings.
authors.affiliation: Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA.
authors.forename: Nan
authors.initials: N
authors.lastname: Shi
authors.forename: Victor M
authors.initials: VM
authors.lastname: Ugaz
mesh_terms: D004247:DNA / Q000737:chemistry* / Q000302:isolation & purification*; D046209:Electrophoresis, Microchip / Q000379:methods*; D010316:Particle Size; D016062:Porosity
chemical_list: D004247:DNA
keywords: DNA; Entropic trapping; Gel electrophoresis; Stochastic resonance