WO2017039080A1

WO2017039080A1 - Sample concentration apparatus and method for extracting concentrated sample by using same

Info

Publication number: WO2017039080A1
Application number: PCT/KR2015/014457
Authority: WO
Inventors: 김성재; 이상준; 박성민
Original assignee: 서울대학교 산학협력단
Priority date: 2015-09-04
Filing date: 2015-12-30
Publication date: 2017-03-09
Also published as: KR20170034951A; KR101749600B1

Abstract

The present invention provides a sample concentration apparatus and a method for extracting the sample by using the same, the sample concentration apparatus comprising: an ion-selective membrane connected to one end of n microchannels so that an ion depletion zone can be formed by ion concentration polarization (ICP); an electrode, formed at the other end of n microchannels, capable of applying voltage; and a pipet tip capable of contacting a central portion of the ion- selective membrane and capable of introducing a solution containing the sample or draining the sample, wherein the solution is separated into a fluid and the sample by the ion concentration polarization phenomenon which is generated by applying voltage to the solution injected into the central portion of the ion-selective membrane through the pipet tip, the separated fluid is drained into the other end of the n microchannels, and the sample is concentrated in the central portion of the ion-selective membrane and is extracted externally through the pipet tip.

Description

Sample concentrating device and concentrated sample extraction method using the same

The present invention relates to a sample concentrating device and a method for extracting a sample concentrated using the same, and more particularly, a sample concentrating device capable of separating and concentrating a sample sample to be detected at a high concentration in a bio-environmental field and concentrated using the same. It relates to a sampling method.

Since the concentration of the sample to be detected in the bio-environment field such as medical, pharmaceutical, drug test, water test, and clinical diagnosis is extremely low, the technique of concentrating the sample to improve the detection and analysis efficiency is very important.

Current methods for sample concentration can be divided into two types according to the scale. First, in a large system, there are lyophilization, osmotic method, precipitation method, ion exchange chromatography, and hygroscopic method. These technologies have the disadvantage of inaccurate accuracy, such as the need for pretreatment or loss of samples, instead of large throughput.

Recent methods for sample concentration in micro systems include Field Amplified Sample Stacking (FASS), Isotachophoresis, Electrokinetic trapping, Micellar electrokinetic sweeping, Chromatographic preconcentration and Membrane preconcentration. In addition, since the concentration is high, but the concentration occurs inside the micro channel, very small amounts of pL to nL are concentrated, so the detection sensitivity is low, and an external control device is necessary for driving the concentration device. There is a problem that can be used smoothly.

The present invention is to solve a number of problems including the above problems, the process is simple, economical, mass production apparatus capable of mass production and concentrated sample extraction method using the same. However, these problems are exemplary, and the scope of the present invention is not limited thereby.

According to one aspect of the invention, a sample concentrating device is provided. The sample concentrating device may include an ion-selective membrane connected to one end of n microchannels so as to form an ion depletion zone by ion concentration polarization (ICP) phenomenon; Electrodes formed at the other ends of the n microchannels to apply a voltage; And a pipette tip capable of contacting a central portion of the ion selective membrane and allowing a solution containing a sample to flow in or out of the sample; and a pipette tip through the pipette tip. The solution is separated into a fluid and the sample by the ion concentration polarization phenomenon generated by applying a voltage to the solution injected into the central portion of the membrane, and the separated fluid flows out to the other ends of the n microchannels. Samples can be concentrated in the central portion of the ion selective membrane and extracted outwards through a pipette tip.

In the sample concentrating device, the ion-selective membrane may comprise a nano-membrane printed in a circular or polygonal shape.

In the sample concentrating device, the ion selective membrane and the electrode may be radially spaced apart from each other.

According to another aspect of the present invention, a sample extraction method is provided. The sample extraction method comprises the steps of supplying a solution comprising a sample to a central portion of a microchannel device having n microchannels and an ion-selective membrane using a pipette tip; By applying a voltage to the microchannel device, an ion concentration polarization (ICP) phenomenon occurs at one end of the n microchannels and the ion selective membrane to form an ion depletion zone. step; And the solution is separated into a fluid and the sample based on the ion depletion region, the fluid flows out through the n microchannel other ends, and the sample is extracted to the outside of the microchannel device through the pipette tip. It may comprise the steps.

In the sample extraction method, the solution is microparticles having a micro-nano size, and the polar particles are dielectrically polarized by an electric field.

In the sample extraction method, the solution may be separated into the fluid and the sample by the force due to the electroosmotic flow and the force due to the ion concentration polarization phenomenon.

In the sample extraction method, the solution may be supplied to the central portion of the microchannel device or the sample separated by the ion concentration polarization phenomenon according to the pressure change on the pipette tip.

In the sample extraction method, the extracting of the sample to the outside of the micro channel device may include collecting the sample extracted through the pipette tip in a separate device.

According to one embodiment of the present invention made as described above, it is possible to implement a method for producing biodiesel from microalgal cells with a simple structure and low power by using a microchannel device having an ion selective membrane. Of course, the scope of the present invention is not limited by these effects.

1A to 1C schematically illustrate a micro channel device according to an embodiment of the present invention.

FIG. 2 is a photograph of the micro channel device shown in FIG.

3 is a photograph of a sample concentrating device and a sample extraction process concentrated using the same according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms, and the following embodiments are intended to complete the disclosure of the present invention, the scope of the invention to those skilled in the art It is provided to inform you completely. In addition, the components may be exaggerated or reduced in size in the drawings for convenience of description.

Embodiments of the present invention will now be described with reference to the drawings, which schematically illustrate ideal embodiments of the present invention. In the figures, for example, variations in the shape shown may be expected, depending on manufacturing techniques and / or tolerances. Accordingly, embodiments of the inventive concept should not be construed as limited to the specific shapes of the regions shown herein, but should include, for example, changes in shape resulting from manufacturing.

1 (a) to (c) is a view schematically showing a micro channel device according to an embodiment of the present invention, Figure 2 is a picture of the micro channel device shown in (a) of FIG.

Referring to (a) to (c) of FIG. 1, the micro channel device 10 according to an embodiment of the present invention may have an ion depletion zone due to ion concentration polarization (ICP). An ion-selective membrane 14 connected to one end of the n microchannels 12 and an electrode 16 formed at the other end of the n microchannels 12 to apply a voltage to form the And a pipette tip 18 capable of contacting the central portion of the ion-selective membrane 14, into which a solution 20 comprising the sample 20a can be introduced, or into which the sample 20a can flow. can do.

First, the ion selective membrane 14 may comprise, for example, a nanomembrane printed in a circular or polygonal shape. The nanomembrane is connected to one end of the n microchannels 12 to be described later, and may be printed as a circular nanomembrane having a uniform shape so that separate concentration of the sample 20a can be reproducibly implemented.

If the ion-selective membrane 14 is not formed in a uniform shape, separation and concentration of the sample 20a may not be performed properly due to a minute error occurring in a portion in contact with the microchannel 12. Thus, the most ideal type of ion selective membrane 14 may be circular in shape, but when the number of micro channels 12 is not large, the ion selective membrane 14 may be easily matched with the portions contacting each of the micro channels 12. ) May be formed in a polygonal shape, and a portion contacting each of the microchannels 12 may be formed flat.

That is, each of the n microchannels 12 may be understood as a straight microchannel, and the edge surface of the nanomembrane contacts one end of each microchannel 12 to overlap each other to form the microchannel device 10. can do. This eliminates fine errors in the manufacturing process of the micro channel device 10 so that the separation concentration of the sample 20a is always stable.

The number of microchannels 12 may be designed differently in number and shape according to the capacity of the sample 20a to be separated and concentrated. In addition, the microchannel device 10 may be designed to be smaller or larger in size than the radial structure by configuring the microchannel 12 in a form arranged in parallel with each other rather than a radial structure. For example, when the thickness of the ion selective membrane 14 is kept constant, the concentration of the sample 20a may be controlled by adjusting the number, length and thickness of each microchannel 12. Further, the concentration of the sample 20a may be controlled according to the magnitude of the voltage applied to the micro channel device 10.

In addition, in order to maximize the separation concentration processing capacity of the sample 20a, a high concentration of the sample 20a may be extracted by stacking at least two microchannel devices 10 formed in a single layer.

The micro channel device 10 may include an electrode 16. The electrodes may be formed at the other ends of the n micro channels 12. The electrode 16 may be arranged differently according to the form in which the n microchannels 12 are disposed. For example, the circular ion-selective membrane 14 and the electrode 16 may be surrounded by the ion-selective membrane 14. Radially spaced apart from each other along the micro-channels 12 coupled to the. If the microchannels 12 are arranged next to each other by using a flat polygonal ion selective membrane 14 instead of a circular ion selective membrane 14, the electrode 16 is ion selective. The membrane 14 may be spaced apart from the membrane 14 by a predetermined distance.

Referring again to FIGS. 1A through 1C, a sample extraction method according to an embodiment of the present invention includes a microchannel device 10 having n microchannels 12 and an ion selective membrane 14. Supplying a solution 20 containing a sample 20a to a central portion of the pipette tip 18 using a pipette tip, applying a voltage to the microchannel device 10, thereby applying n microchannels 12. Ion Concentration Polarization (ICP) occurs at one end of the cation and the ion selective membrane 14 to form an ion depletion zone, and the solution 20 is the ion depletion region. The fluid 20b is separated into a sample 20a based on the fluid, and the fluid 20b flows out through the other ends of the n microchannels 12, and the sample 20a passes through the pipette tip 18. It may include extracting to the outside of the device 10.

More specifically, referring to FIGS. 1A and 1B, a pipette tip 18 is brought into contact with a central portion of the microchannel device 10 to obtain a solution 20 including a sample 20a. Can be injected. Here, the sample 20a may be understood as a sample that can be used in the bioenvironment field. The solution 20 may include microparticles having a micro-nano size and the polarized microparticles may be subjected to dielectric polarization by an electric field. The particulates may be self-assembled and collected near the ion selective membrane 14.

In addition, the ion concentration polarization phenomenon used in one embodiment of the present invention is one of the electrochemical transfer phenomenon observed around the structure having a nano-membrane. It is theoretically known that when the thickness of the electric double layer is similar to the size of the nanomembrane, the polar double layer overlaps inside the nanomembrane and exhibits monopolar ion permeability. That is, most of the surface of the material has its own surface charge when it comes into contact with the liquid. If the microchannel device 10 is made of such a material and the liquid is poured into the microchannel device 10, the surface charge of the material Counter ions form an electrical double layer. The electrical double layer has a thickness of several nanometers to several hundred nanometers, and has a selective permeability to pass only ions of opposite polarity to nano size.

In this case, when the micro-nano structure is combined and the liquid is filled in the structure and the voltage is applied, an ion concentration polarization phenomenon occurs in which an ion depletion layer is formed at one side of the nanomembrane and an ion floating layer is at the opposite side by a selective permeable nanomembrane. When the circular cation-selective nanomembrane 14 is coupled to the n microchannels 12 using this, negatively charged samples can be simultaneously concentrated in the direction where the potential is high due to the ion concentration polarization phenomenon.

For example, after making a micro-nano multi-channel coupling structure, a solution containing a sample is injected into the top of the micro multi-channel, and a pressure and voltage are applied to cause ion concentration polarization due to ion concentration. do. Samples are subjected to dielectric polarization by an external electric field, behaving like charged particles, and subjected to electrostatic forces at the edge of the ion depletion layer resulting from ion concentration polarization, which are pushed away from the nanomembrane.

That is, the fluid containing the sample depends on the force F _drag = -6πμＵα (Ｕ is the flow rate, μ is the viscosity of the sample and α is the representative radius of the particle) and the force F _EOF by the electroosmotic flow. The sample is moved to the microchannel, and the sample is pushed out of the ion depletion layer by the force F _ICP due to the ion concentration polarization phenomenon and concentrated in the central portion of the microchannel device 10. By collecting the concentrated samples separately, high concentration sample samples can be obtained.

Referring to FIGS. 1B and 1C, after a solution containing a sample enters a central portion of the micro channel device 10, a pipette tip inserted into the central portion of the micro channel device 10 ( 18), a voltage may be applied to the electrode 16 while applying pressure. The ion depletion (ion depletion) occurs by simultaneously applying the ion concentration polarization (ICP) to a portion adjacent to the branching point where the ion selective membrane 14 and the n microchannels 12 are in contact with the applied pressure and voltage. zones). The introduced solution 20 may be separated into the fluid 20b and the sample 20a based on the ion depletion region. In the separation process, the sample 20a may be pushed out from the interface of the ion depletion region by the force of the electroosmotic flow and the force of the ion concentration polarization phenomenon.

On the other hand, the separated fluid 20b flows outward to the center of the microchannel 12, and the sample 20a is pushed out by the electric repulsive force at the interface of the ion depletion region to the center portion where the ion selective membrane 14 is disposed. Can be concentrated. The pipette tip 18 may again contact the central portion of the micro channel device 10 and then apply pressure to collect the concentrated sample 20a into a separate device (not shown), and the concentrated sample 20a If collected separately, a high concentration of sample can be extracted. Herein, the separated sample 20a may be extracted using the same pipette tip 18 used to inject the solution 20 into the microchannel device 10, It is also possible to use an alternative to a mechanism that can apply pressure or allow material to pass through the outlet portion formed in the central portion of the channel device 10.

Referring to FIGS. 1A and 2, the microchannel device 10 may control the concentration of a sample according to the number of microchannels. Specifically, FIG. 2A illustrates the microchannel 12. 2 is a micro channel device 10 having 4, and FIG. 2B illustrates a micro channel device 10 having 8 micro channels 12.

The micro channel device 10 may use a transparent material as the first substrate. For example, one of pyrex, silicon dioxide, silicon nitride, quartz or SU-8 may be used as the first substrate. The micro channel device 10 is coated with a low-autofluorescent material. In addition to the first substrate, a second substrate may be included. The second substrate can be used to cover or seal the micro channel device 10. The second substrate may be made of the same material as the first substrate. Depending on the solution used in some embodiments, the first substrate and the second substrate may be made of different materials.

Meanwhile, the manufacture of the micro channel device 10 can be completed by plasma bonding the first substrate to the second substrate. The substrate is a support structure of the micro channel device 10. At least a portion of the substrate may be made of silicon. In one embodiment of the invention, the substrate, device or portions of the device may be made of a polymer. The polymer may be polydimethylsiloxane (PDMS). When PDMS is used, oxygen (O ₂ ) plasma may be treated to have hydrophilicity, but oxygen plasma treatment may be omitted in some cases.

In addition, the solution 20 may include an introduction portion protruding upward in the central portion of the micro channel device 10 so that the solution 20 may be introduced or the concentrated sample 20a may flow out. One end of the n microchannels 12 may be disposed with an ion selective membrane 14 to be electrically grounded (GND). By ion selective membrane 14, sample 20a comprising charged species in solution introduced through the inlet can be concentrated in the central portion where ion selective membrane 14 is disposed, and the non-charged species The fluid 20b including may be discharged to the other ends of the n micro channels 12. Here, the ion selective membrane 14 may use, for example, Nafion.

In addition, the ion selective membrane 14 may be predominantly behaving against cations that do not match the ionic conductivity in the electrolyte. As a result, ion concentration gradients can be generated on both sides of the ion selective membrane 14. Once ion concentration polarization is induced near the cation exchange ion selective membrane 14, both the cation and anion concentrations decrease on the anode side and increase on the cathode side of the junction. Moreover, charged particles, cells, other small colloids, and the like, may similarly exhibit ion depletion or ionic hyperplasia, which makes it possible to obtain a depletion region in rectified state.

Hereinafter, an experimental example to which the above-described technical concept is applied will be described to help understanding of the present invention. However, the following experimental examples are only for helping understanding of the present invention, and the present invention is not limited to the following experimental examples.

As a sample according to the experimental example of the present invention, a circular electrode is deposited on the other end of the microchannel using a metal deposition technique in a microchannel coupling structure having four legs on a circularly printed nanofilm. Later, using a pipette tip, about 990 μl of deionize water (DI), about 10 μl of 100 mM potassium chloride (KCl), and about 2 μl of Alexa 488 in the central portion of the microchannel bonding structure The mixed solution was injected, and a concentration of about 70 V and a circular electrode at the other end of the micro channel using a voltage applying device in the center of the micro channel was concentrated after about 10 and 60 seconds. It photographed with the fluorescent light source of 480 nm wavelength band.

Specifically, (a) of FIG. 3 is a microscopic photograph of a microchannel structure in which a circular ion-selective membrane and four microchannels are combined, and (b) of FIG. 3 is a voltage applied to the microchannel structure. The microscopic structure was analyzed by a microscope while applying a fluorescent light source to the microchannel structure after about 10 seconds, Figure 3 (c) is a microscope while applying a fluorescent light source to the microchannel structure after about 60 seconds after applying a voltage to the microchannel structure This is a photograph analyzed.

Referring to (a) to (c) of FIG. 3, the sample and the fluid are formed by an ion depletion region formed in the vicinity of the ion selective membrane and the four microchannels as time passes after the voltage is applied to the microchannel structure. It can be seen that it is separated into and concentrated to the central portion of the microchannel structure by electrostatic repulsive force.

As described above, the present invention is based on a low cost device based on PDMS with a micro-nano channel binding system, and can concentrate ions in an aqueous solution to a high concentration. Increasing the number of microchannels compensates for the disadvantages of the microconcentrator with low sample throughput and detection sensitivity, and compensates for the disadvantages of low-accuracy bulk concentrators by adjusting pressure and voltage.

In addition, by changing the shape of the nanomembrane freely using printing, it is easy to adjust the concentration of the concentrating device, and it is possible to use the pipette tip generally used in the laboratory, thereby increasing the market entry.

On the other hand, the denatured protein test in the blood flow is widely used as an indicator of the diagnosis of the disease, the amount of protein in the blood flow is very small, so the concentration process is necessary to detect and analyze it. In addition, heavy metals can have a deadly effect when accumulated in a very small amount in a living body, so it is important to concentrate them at a high concentration when detecting heavy metals, and to detect harmful substances such as fine heavy metals in foods that humans consume such as heavy metals detection. In the field of detecting and the general bio-system is very small amount of the sample, the concentration of the sample concentration device according to the embodiments of the present invention, and the like, the field that needs to detect or maximize the concentration or the experiment to maximize the concentration thereof Concentrated sample extraction methods can be applied.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims

An ion-selective membrane connected to one end of n microchannels so as to form an ion depletion zone by an ion concentration polarization (ICP) phenomenon;

Electrodes formed at the other ends of the n microchannels to apply a voltage; And

A pipette tip capable of contacting a central portion of the ion-selective membrane, into which a solution containing a sample may be introduced, or into which the sample may flow out;

Including,

The solution is separated into a fluid and the sample by the ion concentration polarization phenomenon generated by applying a voltage to the solution injected into the central portion of the ion selective membrane through the pipette tip, and the separated fluid is n Out of the other two microchannels, the sample is concentrated in a central portion of the ion-selective membrane and extracted outside through a pipette tip,

Sample concentrator.
The method of claim 1,

The ion selective membrane comprises a nano-membrane printed in a circular or polygonal shape,

Sample concentrator.
The method of claim 1,

Wherein the ion selective membrane and the electrode are radially spaced apart from each other,

Sample concentrator.
supplying a solution comprising a sample to a central portion of a microchannel device having n microchannels and an ion-selective membrane using a pipet tip;

By applying a voltage to the microchannel device, an ion concentration polarization (ICP) phenomenon occurs at one end of the n microchannels and the ion selective membrane to form an ion depletion zone. step; And

The solution is separated into a fluid and the sample based on the ion depletion region, the fluid flows out through the n microchannel other ends, and the sample is extracted to the outside of the microchannel device through the pipette tip. step;

Including,

Sample extraction method.
The method of claim 4, wherein

The solution is micro-nano sized microparticles, and the polarized microparticles can be subjected to dielectric polarization by an electric field,

Sample extraction method.
The method of claim 4, wherein

The solution is separated into the fluid and the sample by the force of the electroosmotic flow and the force of the ion concentration polarization phenomenon,

Sample extraction method.
The method of claim 4, wherein

Wherein the sample is supplied to the central portion of the microchannel device or the sample separated by the ion concentration polarization is extracted according to the pressure change on the pipette tip,

Sample extraction method.
The method of claim 4, wherein

Extracting the sample to the outside of the micro channel device,

Collecting the sample extracted through the pipette tip in a separate device;

Sample extraction method.