Abstract: Provided is a method of controlling the pH of a solution using electrolysis in a microfluidic device comprising an electrolysis device including an anode chamber, a cathode chamber, and a partition membrane between the anode chamber and the cathode chamber, wherein the anode chamber includes an inlet and an outlet through which an anode chamber solution enters and is discharged from the anode chamber, respectively, and an electrode, and the cathode chamber includes an inlet and an outlet through which a cathode chamber solution enters and is discharged from the cathode chamber, respectively, and an electrode.

Abstract: Provided is a microfluidic device for electrochemically regulating the pH of a fluid comprising: a cathode substrate; an anode substrate facing the cathode substrate and forming a reaction chamber with the cathode substrate; and a nonconductor which forms a boundary between the portions of the cathode substrate and the anode substrate that are capable of contacting one another, wherein at least one of the cathode substrate and the anode substrate is a semiconductor doped with impurities and the other is a metal electrode.

Abstract: Provided is a microfluidic device for electrochemically regulating the pH of a fluid comprising: a cathode substrate; an anode substrate facing the cathode substrate and forming a reaction chamber with the cathode substrate; and a nonconductor which forms a boundary between the portions of the cathode substrate and the anode substrate that are capable of contacting one another, wherein at least one of the cathode substrate and the anode substrate is a semiconductor doped with impurities and the other is a metal electrode.

Abstract: Provided are a sensing switch and a sensing method using the same. The sensing switch includes: a substrate; a supporter on the substrate; a sensing plate that is connected to a side of the supporter and is in parallel with the substrate by a predetermined distance; a receptor binding region on an upper surface of an end portion of the sensing plate; an electric or magnetic field generation device that induces deflection of the sensing plate when a receptor bound to the receptor binding region is selectively bound to an electrically or magnetically active ligand; and a pair of switching electrodes that are separated by a predetermined distance and is connected when the sensing plate contacts the substrate due to the deflection of the sensing plate. A target material need not be labelled, a signal processing of a fluorescent or electrical detection signal using an analysis apparatus is not required, and a signal can be directly decoded by confirming whether a current flows through the switch.

Abstract: Provided are a microfluidic chip and a method of fabricating the same. The microfluidic chip includes: a lower substrate; an upper substrate formed of a silicone resin, wherein the lower substrate and the upper substrate, bonded together, provide a channel through which a fluid can flow and a chamber to receive the fluid; and an organic thin film formed on the upper surface of the lower substrate except for portions on which the lower substrate and the upper substrate are attached to each other.

Abstract: Provided is a method of isolating and purifying nucleic acids using an immobilized hydrogel or polyethylene glycol (PEG)-hydrogel copolymer. The method includes: immobilizing a functional group-containing hydrogel or PEG-hydrogel copolymer on a substrate; adding a mixed sample solution containing a salt and nucleic acids to the hydrogel- or PEG-hydrogel copolymer-immobilized substrate to bind the nucleic acids to the hydrogel or the PEG-hydrogel copolymer; washing the nucleic acid-bound hydrogel or PEG-hydrogel copolymer; and eluting the nucleic acids from the hydrogel or the PEG-hydrogel copolymer using an elution solvent. Therefore, binding and elution of nucleic acids can be performed even with no addition of a separate chemical substance, and an effect on a subsequent process such as PCR can be minimized. Furthermore, the amount and intensity for binding nucleic acids can be adjusted according to PEG concentration, and the presence of a hydrogel compound on a substrate enables patterning.

Abstract: Provided are a sensing switch and a sensing method using the same. The sensing switch includes: a substrate; a supporter on the substrate; a sensing plate that is connected to a side of the supporter and is in parallel with the substrate by a predetermined distance; a receptor binding region on an upper surface of an end portion of the sensing plate; an electric or magnetic field generation device that induces deflection of the sensing plate when a receptor bound to the receptor binding region is selectively bound to an electrically or magnetically active ligand; and a pair of switching electrodes that are separated by a predetermined distance and is connected when the sensing plate contacts the substrate due to the deflection of the sensing plate. A target material need not be labelled, a signal processing of a fluorescent or electrical detection signal using an analysis apparatus is not required, and a signal can be directly decoded by confirming whether a current flows through the switch.

Abstract: Provided is a microfluidic device for electrochemically regulating the pH of a fluid. The microfluidic device includes: an ion-exchange material; an anode chamber having a surface defined by a surface of the ion-exchange material and an anode electrode disposed along an edge of the surface of the anode chamber; and a cathode chamber having a surface defined by a surface of the ion-exchange material and a cathode electrode disposed along an edge of the surface of the cathode chamber, wherein the anode chamber and the cathode chamber are separated by an insulation material.

Abstract: A microfluidic valve unit for controlling the flow of fluid flowing along a channel, and a method of fabricating the same are provided. The valve unit includes a channel formed in a platform; a valve filler which includes a phase transition material that is disposed in the channel in a solid state at room temperature to close the channel and is melted when energy is applied thereto; and at least one capillary channel which extends from a sidewall of the channel and into which the valve filler flows when the valve filler is melted, wherein the at least one capillary channel has a cross-sectional area which is less than a cross-sectional area of the channel.

Abstract: Provided is a fluid mixing device which produces a series of solutions with a concentration gradient. The fluid mixing device includes: a plurality of first channels disposed parallel to each other on a layer, and into which an equal amount of diluent flows from its upstream; a plurality of second channels formed perpendicular to the first channels on an adjacent layer to the layer on which the first channels are formed, and into which an equal amount of sample solution flows from its upstream; and via holes formed at at least one intersection between each of the first channel and a plurality of second channels so that a predetermined amount of sample solution flows from the second channels into corresponding first channels, wherein a series of solutions with different concentrations is produced in the first channels depending on the amount of sample solution that flows into the first channels through the via holes. Thus, a series of solutions with different concentrations is output from the first channels.

Abstract: An apparatus for regulating salt concentration, a lab-on-a-chip including the same and a method of regulating salt concentration using the apparatus are provided. The apparatus includes: a reaction chamber that is defined by a cation exchange membrane and an anion exchange membrane and is selected from the group consisting of a biomolecule extraction chamber, an amplification chamber, a hybridization chamber, and a detection chamber; a first electrode chamber that is defined by the anion exchange membrane and a first electrode and includes an ion exchange medium; and a second electrode chamber that is defined by the cation exchange membrane and a second electrode and includes an ion exchange medium. Even without injecting solutions with different salt concentrations into the reaction chamber by operating pumps and valves for each operation stage, the salt concentration can be reversibly regulated in situ by adjusting the polarity, intensity and application time of a voltage.

Abstract: Provided are a method of separating genome DNA and plasmid DNA from each other from a sample using a binding buffer containing a high concentration kosmotropic salt and chaotropic salt, and a kit therefor.

Abstract: Provided are a microfluidic structure including a polysiloxane layer and a method of fabricating the microfluidic structure. The polysiloxane layer is coupled to substrates via a SiO2 layer.

Abstract: A method of isolating nucleic acid from a sample containing nucleic acid is provided. The method includes contacting the sample with a bifunctional material that contains an amino group and a carboxyl group and is positively charged at a first pH to allow binding of the nucleic acid to the bifunctional material; and extracting the nucleic acid at a second pH higher than the first pH from the complex.

Abstract: Provided are a bi-functional compound that is positively charged at a first pH and negatively charged at a second pH, a solid support having the bi-functional compound immobilized thereon, and a method of isolating a nucleic acid, including: binding the bi-functional compound with a nucleic acid at a first pH and isolating the nucleic acid from the bi-functional compound at a second pH.

Abstract: Provided are a microfluidic chip for multiple bioassay and a method of manufacturing the same. The method includes: forming microfluidic channels by coupling a channel structure having grooves for sample channels and probe channels in a bottom surface and a substrate; forming probe immobilization regions at intersections between the probe channels and the sample channels; and forming blocking walls in the probe channels before and after each of the probe immobilization regions to prevent mixing of target sample. Since the probes are immobilized in the microfluidic channels after the formation of the microfluidic channels, difficulty in connecting fluidic channels after the immobilization of probes on a substrate can be removed. In addition, a microfluidic platform for a multiple bioassay into which a plurality of samples can be simultaneously loaded can be formed.

Abstract: A method and apparatus for amplifying nucleic acids. The method includes introducing into a reaction vessel via different inlet channels a reactant aqueous solution containing reactants for nucleic acid amplification and a fluid that is phase-separated from the reactant aqueous solution and does not participate in amplification reaction, creating a plurality of reactant aqueous solution droplets surrounded by the fluid by contacting the reactant aqueous solution with the fluid in the reaction vessel, and amplifying the nucleic acids in the reactant aqueous solution droplets.

Abstract: A method and apparatus for amplifying nucleic acids. The method includes introducing into a reaction vessel via different inlet channels a reactant aqueous solution containing reactants for nucleic acid amplification and a fluid that is phase-separated from the reactant aqueous solution and does not participate in amplification reaction, creating a plurality of reactant aqueous solution droplets surrounded by the fluid by contacting the reactant aqueous solution with the fluid in the reaction vessel, and amplifying the nucleic acids in the reactant aqueous solution droplets.

Abstract: Provided is a lysis method for cells or viruses, including: immobilizing a metal-ligand complex on a solid support; and mixing the complex immobilized on the support with a cell or virus solution. According to the lysis method, by immobilizing a chemical on a solid support to perform cell lysis, the dilution problem according to the addition of a cell lysis solution can be resolved and a separate process of removing the chemical is not required so as to reduce the steps upon LOC implementation. In addition, since a variety of solid supports, such as chips, beads, nanoparticles etc. can be used, cell lysis apparatuses of various forms can be fabricated.

Abstract: Provided is a method comprising adding anions having a high charge density to a liquid medium; the liquid medium comprising molecules that hydrogen bond with one another; the anions interacting with the molecules of the liquid medium with a force that is stronger than the forces that produce hydrogen bonding between the molecules of the medium; and heating the liquid medium by irradiating it with microwaves.