title: Increasing hybridization rate and sensitivity of bead-based assays using isotachophoresis.
abstract: We present an electrokinetic technique to increase the reaction rate and sensitivity of bead-based assays. We use isotachophoresis (ITP) to preconcentrate and co-focus target molecules and beads into a single ITP zone. The process achieves rapid mixing, stirring, and strongly increases the binding reaction rate. We demonstrate our assay with quantitative detection of 24 nt single-stranded DNA over a dynamic range of three orders of magnitude and multiplexed detection of ten target species per sample. We show that ITP can achieve approximately the same sensitivity as a well-stirred standard reaction in 60-fold reduced reaction time (20 min versus 20 h). Alternately, compared to standard reaction times of 30 min, we show that 20 min ITP hybridization can achieve 5.3-fold higher sensitivity.
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (USA); Department of Micro Engineering, Kyoto University, Nishikyo, Kyoto 615-8540 (Japan).
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Shintaku
authors.forename: James W
authors.initials: JW
authors.lastname: Palko
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Sanders
authors.forename: Juan G
authors.initials: JG
authors.lastname: Santiago
mesh_terms: D057625:Isotachophoresis; D057230:Limit of Detection
keywords: DNA analysis; hybridization assay; isotachophoresis; multiplexing