title: Selective Trapping of DNA Using Glass Microcapillaries.
abstract: We show experimentally that an inexpensive glass microcapillary can accumulate λ-phage DNA at its tip and deliver the DNA into the capillary using a combination of electro-osmotic flow, pressure-driven flow, and electrophoresis. We develop an efficient simulation model based on the electrokinetic equations and the finite-element method to explain this phenomenon. As a proof of concept for the generality of this trapping mechanism we use our numerical model to explore the effect of the salt concentration, the capillary surface charge, the applied voltage, the pressure difference, and the mobility of the analyte molecules. Our results indicate that the simple microcapillary system has the potential to capture a wide range of analyte molecules based on their electrophoretic mobility that extends well beyond our experimental example of λ-phage DNA. Our method for separation and preconcentration of analytes therefore has implications for the development of low-cost lab-on-a-chip devices.
authors.affiliation: Institute for Computational Physics (ICP), University of Stuttgart , Allmandring 3, 70569 Stuttgart, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Rempfer
authors.affiliation: Institute for Computational Physics (ICP), University of Stuttgart , Allmandring 3, 70569 Stuttgart, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Ehrhardt
authors.affiliation: Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, United Kingdom.
authors.forename: Nadanai
authors.initials: N
authors.lastname: Laohakunakorn
authors.affiliation: Institute for Computational Physics (ICP), University of Stuttgart , Allmandring 3, 70569 Stuttgart, Germany.
authors.forename: Gary B
authors.initials: GB
authors.lastname: Davies
authors.affiliation: Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, United Kingdom.
authors.forename: Ulrich F
authors.initials: UF
authors.lastname: Keyser
authors.affiliation: Institute for Computational Physics (ICP), University of Stuttgart , Allmandring 3, 70569 Stuttgart, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Holm
authors.affiliation: Institute for Computational Physics (ICP), University of Stuttgart , Allmandring 3, 70569 Stuttgart, Germany.
authors.forename: Joost
authors.initials: J
authors.lastname: de Graaf
mesh_terms: D010582:Bacteriophage lambda / Q000737:chemistry; D003198:Computer Simulation; D004279:DNA, Viral / Q000302:isolation & purification*; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000706:statistics & numerical data; D004867:Equipment Design; D020342:Finite Element Analysis; D005898:Glass; D056656:Lab-On-A-Chip Devices / Q000706:statistics & numerical data; D009997:Osmotic Pressure
chemical_list: D004279:DNA, Viral