title: Probing DNA with micro- and nanocapillaries and optical tweezers.
abstract: We combine for the first time optical tweezer experiments with the resistive pulse technique based on capillaries. Quartz glass capillaries are pulled into a conical shape with tip diameters as small as 27 nm. Here, we discuss the translocation of λ-phage DNA which is driven by an electrophoretic force through the nanocapillary. The resulting change in ionic current indicates the folding state of single λ-phage DNA molecules. Our flow cell design allows for the straightforward incorporation of optical tweezers. We show that a DNA molecule attached to an optically trapped colloid is pulled into a capillary by electrophoretic forces. The detected electrophoretic force is in good agreement with measurements in solid-state nanopores.
authors.affiliation: Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: L J
authors.initials: LJ
authors.lastname: Steinbock
authors.forename: O
authors.initials: O
authors.lastname: Otto
authors.forename: D R
authors.initials: DR
authors.lastname: Skarstam
authors.forename: S
authors.initials: S
authors.lastname: Jahn
authors.forename: C
authors.initials: C
authors.lastname: Chimerel
authors.forename: J L
authors.initials: JL
authors.lastname: Gornall
authors.forename: U F
authors.initials: UF
authors.lastname: Keyser
mesh_terms: D002197:Capillary Action; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D019075:Electrophoresis, Capillary / Q000379:methods*; D015336:Molecular Probe Techniques; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D052898:Optical Tweezers; D016062:Porosity; D013499:Surface Properties
chemical_list: D004247:DNA