title: Pneumatic handling of droplets on-demand on a microfluidic device for seamless processing of reaction and electrophoretic separation.
abstract: Sequential operations of pre-separation reaction process by picoliter droplets and following electrophoretic separation process were realized in a single microfluidic device with pneumatic handling of liquid. The developed device consists of a fluidic chip made of PDMS, an electrode substrate, and a temperature control substrate on which thin film heater/sensor structures are fabricated. Liquid handling, including introduction of liquid samples, droplet generation, and merging of droplets, was implemented by pneumatic manipulation through microcapillary vent structures, allowing air to pass and stop liquid flow. Since the pneumatic manipulations are conducted in a fully automated manner by using a programmable air pressure control system, the user simply has to load liquid samples on each liquid port of the device. Droplets of 420 pL were generated with an accuracy of ± 2 pL by applying droplet generation pressure in the range of 40-100 kPa. As a demonstration, a binding reaction of a 15 mer ssDNA with a peptide nucleic acid oligomer used as an oligoprobe followed by denaturing electrophoresis to discriminate a single-base substitution was performed within 1.5 min. By exploiting the droplet-on-demand capability of the device, the influence of various factors, such as reaction time, mixing ratio and droplet configurations on the ssDNA-peptide nucleic acid binding reaction in the droplet-based process, was studied toward realization of a rapid detection method to discriminate rapid single-base substitution.
authors.affiliation: LIMMS-CNRS/IIS, Institute of Industrial Science, University of Tokyo, Tokyo, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Kaneda
authors.forename: Koichi
authors.initials: K
authors.lastname: Ono
authors.forename: Tatsuhiro
authors.initials: T
authors.lastname: Fukuba
authors.forename: Takahiko
authors.initials: T
authors.lastname: Nojima
authors.forename: Takatoki
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Teruo
authors.initials: T
authors.lastname: Fujii
mesh_terms: D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D004252:DNA Mutational Analysis; D004277:DNA, Single-Stranded / Q000737:chemistry; D004586:Electrophoresis / Q000379:methods*; D006801:Humans; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D020135:Peptide Nucleic Acids / Q000737:chemistry
chemical_list: D004277:DNA, Single-Stranded; D020135:Peptide Nucleic Acids; D019005:Cystic Fibrosis Transmembrane Conductance Regulator