title: DNA separation and enrichment using electro-hydrodynamic bidirectional flows in viscoelastic liquids.
abstract: DNA size separation followed by purification and enrichment constitute essential operations for genetic engineering. These processes are mostly carried out using DNA electrophoresis in gels or in polymer solutions, a well-established yet lengthy technique which has been notably improved using Lab-on-Chip technologies. So far, innovations for DNA separation or enrichment have been mostly undertaken separately, and we present an approach that allows us to perform these two processes simultaneously for DNA fragments spanning 0.2-50 kilo base pairs (kbp) in length. Our technology involves an electric field and a counter hydrodynamic flow in viscoelastic liquids, in which we show the occurrence of transverse forces oriented toward the walls. These forces increase with DNA molecular weight (MW) and hence induce a progressive reduction in DNA migration speed that triggers size separation in microfluidic channels as well as in capillaries. The separation of MW markers in the range 1-50 kbp is achieved in 15 minutes, thus outperforming gel electrophoresis that takes ∼3 hours for this sample. Furthermore, the use of a funnel, where electric and flow fields are modulated spatially, enables us to adjust the transverse forces so as to stall the motion of DNA molecules at a position where they accumulate at factors of up to 1000 per minute. In this configuration, we establish that the operations of DNA enrichment and separation can be carried out simultaneously for the bands of a DNA MW marker between 0.2-1.5 kbp diluted at 0.02 ng μL(-1) in 30 s. Altogether, our technology, which can readily be integrated as an in-line module in Lab-on-Chips, offers unique opportunities for sample preparation and analysis of minute genomic samples.
authors.affiliation: CNRS, LAAS, 7 avenue du colonel Roche, F-31400 Toulouse, France. abancaud@laas.fr and Univ de Toulouse, LAAS, F-31400 Toulouse, France.
authors.forename: Hubert
authors.initials: H
authors.lastname: Ranchon
authors.affiliation: CNRS, LAAS, 7 avenue du colonel Roche, F-31400 Toulouse, France. abancaud@laas.fr and Univ de Toulouse, LAAS, F-31400 Toulouse, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Malbec
authors.affiliation: Picometrics Technologies, 478 rue de la Découverte, Miniparc Bât 1, 31670 Labège, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Picot
authors.affiliation: Picometrics Technologies, 478 rue de la Découverte, Miniparc Bât 1, 31670 Labège, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Boutonnet
authors.affiliation: CNRS, LAAS, 7 avenue du colonel Roche, F-31400 Toulouse, France. abancaud@laas.fr and Univ de Toulouse, LAAS, F-31400 Toulouse, France.
authors.forename: Pattamon
authors.initials: P
authors.lastname: Terrapanich
authors.affiliation: CNRS, LAAS, 7 avenue du colonel Roche, F-31400 Toulouse, France. abancaud@laas.fr and Univ de Toulouse, LAAS, F-31400 Toulouse, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Joseph
authors.affiliation: CNRS, LAAS, 7 avenue du colonel Roche, F-31400 Toulouse, France. abancaud@laas.fr and Univ de Toulouse, LAAS, F-31400 Toulouse, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Leïchlé
authors.affiliation: CNRS, LAAS, 7 avenue du colonel Roche, F-31400 Toulouse, France. abancaud@laas.fr and Univ de Toulouse, LAAS, F-31400 Toulouse, France.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Bancaud
mesh_terms: D004247:DNA / Q000737:chemistry / Q000302:isolation & purification*; D004548:Elasticity; D057446:Hydrodynamics; D056656:Lab-On-A-Chip Devices; D008970:Molecular Weight; D014783:Viscosity
chemical_list: D004247:DNA