JP2015199028A - Method of injecting liquid into micro-channel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection method which has a simple configuration without use of liquid feed tubes, connectors, pumps or valves, is reduced in the use amount of a liquid and suppresses leakage of a liquid during injection.SOLUTION: A method of injecting a liquid into a micro-channel comprises a step of extracting a liquid contained in a sample container through suction with a pipette tip attached to the tip of a micro-pipette, a step of pressing the pipette tip toward an introduction port of a micro-channel of a micro tip and a step of injecting and feeding the liquid from the pipette tip into the micro-channel with a compressed gas supplied from the micro-pipette, conducted in this order. The liquid injected and fed from the pipette tip into the micro-channel is sealed with a gasket composed of an elastomer, and a reactive force capable of resisting the liquid injection pressure is generated by compressing deforming the gasket when the pipette tip is pressed toward the micro-channel introduction port.

Description

  The present invention relates to a method for injecting liquid into a microchannel, and more specifically, a microfluidic chip, a microfluidic device, a microchemical chip, a microchannel device, a microdiagnostic device, and the like (hereinafter, these are also collectively referred to as a microchip). ) To inject a liquid such as a reagent into a flow path, that is, a microchannel.

  As known by the name of Micro Total Analysis Systems (μTAS) or Lab-on-Chip, the microchannels and ports that constitute the flow path of a predetermined shape in the substrate A microfluidic chip that is provided with a fine structure and performs various operations such as chemical reaction, synthesis, purification, extraction, generation and / or analysis of substances within the fine structure has attracted attention. Microfluidic chips are expected to be applied to a wide range of applications such as genomic analysis, genomic drug discovery, protein analysis, preventive diagnosis, clinical diagnosis or drug screening, and chemical analysis, food analysis or environmental monitoring. .

  Furthermore, the microfluidic chip uses a small amount of sample and reagent as compared with the conventional method, can be disposable, and can greatly reduce the analysis processing time. Further, the inspection cost can be reduced and the inspection result can be presented quickly.

  In the microfluidic chip, it is necessary to inject a liquid such as a reagent from the inlet into the microchannel in the microfluidic chip through the liquid feeding tube. Usually, at this time, a joint for connecting and fixing the liquid feeding tube and the microfluidic chip at the injection port is required (Non-Patent Document 1). At that time, a method using an adhesive has been devised as a method for fixing the liquid feeding tube and the microfluidic chip. However, when an adhesive is used, it is necessary to bond the liquid feeding tube and the microfluidic chip, which is complicated.

  On the other hand, a joint method by fitting and embedding a liquid feeding tube has been proposed. However, since the liquid is sent to the microchannel in the microfluidic chip, the injection pressure may become high, and the joint due to fitting / embedding may come off and liquid leakage may occur. On the other hand, there is a method of jointing using a screw mechanism, but it takes time to mount and release. In addition, the liquid feeding tube may be twisted during connection.

  On the other hand, there is a method of jointing the liquid feeding tube by pressing it against the microfluidic chip via an O-ring. However, this method requires a jig for pressing the liquid feeding tube against the microfluidic chip (Patent Document 1).

  Furthermore, since all of the above methods require a liquid feeding tube, a new measurement requires cleaning and replacement work to prevent contamination. In addition, a microfluidic chip equipped with a pump and a valve has a drawback in that the manufacturing cost increases because the configuration is complicated.

  On the other hand, an injection method that does not use a liquid feeding tube or a connector has been devised (Patent Document 2). However, since the diaphragm pump is used, the configuration becomes complicated and the manufacturing cost increases. On the other hand, a method of feeding liquid with compressed air without using a pump has been devised (Patent Document 3). However, this method requires a relatively large amount of liquid because the vial is directly brought into contact with the microfluidic chip. Further, the configuration is complicated, for example, the vials are brought into contact with the microfluidic chip and then rotated by a rotating mechanism.

  In view of the above, there is a need for a method for injecting liquid into a microfluidic chip that does not use a liquid feeding tube, a connector, a pump, a valve, and the like, has a simple configuration, and uses a small amount of liquid.

Micro Chemical Chip Technology and Applications Published by Maruzen Co., Ltd. p299-300

JP 2007-152151 A JP 2008-64545 A JP 2012-198050 A

  In view of the above points, the present invention has a simple configuration without using liquid-feeding equipment such as a liquid-feeding tube, a connector, a pump, and a valve, uses a small amount of liquid, and further suppresses liquid leakage during injection. It is an object to provide a method for injecting liquid into a microchannel.

  In order to achieve the above object, a method for injecting a liquid into a microchannel according to claim 1 of the present invention includes a step of aspirating and collecting a liquid contained in a sample container with a micropipette or a pipette tip attached to the tip of the micropipette. A step of pressing the micropipette or the pipette tip against a microchannel introduction port of the microchip, and injecting and feeding the liquid from the micropipette or the pipette tip to the microchannel by a compressed gas supplied from the micropipette. And sequentially sealing the liquid to be injected and sent from the micropipette or the pipette tip to the microchannel with a gasket made of an elastic body, and the micropipette or the pipette tip is connected to the microchannel. The reaction force that may counteract the liquid injection pressure by the gasket is compressive deformed when pressed against the inlet, characterized in that generating the gasket.

  According to a second aspect of the present invention, there is provided a method for injecting a liquid into a microchannel, wherein the gasket is held in advance at the tip of the micropipette or the pipette tip. It is characterized by that.

  According to a third aspect of the present invention, there is provided a method for injecting a liquid into a microchannel, wherein the gasket is held in advance in a film body temporarily fixed to the microchip. It is characterized by.

  The micropipette or pipette tip according to claim 4 of the present invention is a micropipette or pipette tip used for carrying out the liquid injection method according to claim 2 described above, and a gasket is held at the tip thereof. It is characterized by.

  Furthermore, a film body according to claim 5 of the present invention is a film body used for carrying out the liquid injection method according to claim 3 described above, and a pressure-sensitive adhesive is applied to one surface of the thickness direction and the thickness direction is applied. A gasket is held on the other surface, and a through-hole that communicates the inner circumferential space of the gasket and the microchannel inlet is provided.

  In the present invention having the above-described configuration, the amount of liquid to be injected is only the amount sucked by the micropipette or pipette tip, so that the required amount of liquid is very small. Moreover, it is not necessary to connect the microchip and the liquid feeding tube with a connector, and it is not necessary to use the liquid feeding tube itself. In addition, a pump and a valve are not used, and the configuration is simple. In addition, since the number of parts is small and the configuration is simple, the manufacturing cost is low, and it can be disposable. Therefore, the cleaning operation is unnecessary and there is no contamination by the sample. Further, liquid leakage at the time of injection is suppressed by a sealing action by a gasket previously held on the tip of the micropipette or pipette tip or a film body temporarily fixed to the microchip. In addition, by using an automatic pipette device or a pipetting robot to press the micropipette or the pipette tip against the microchip, the liquid can be injected with a simple system configuration. Also, the injection can be automated. Furthermore, by using a multi-channel pipette, it is possible to inject liquid into a plurality of microchips simultaneously.

Sectional drawing which shows an example of the pipette tip used for implementation of the liquid injection method based on the Example of this invention Sectional drawing which shows the other example of the same pipette tip with (A) and (B) Sectional drawing which shows the other example of the same pipette tip with (A) and (B) The perspective view which shows an example of the pipette tip used for implementation of the liquid injection | pouring method which concerns on the other Example of this invention, and a film body. Sectional drawing which shows the same pipette tip and a film body with (A) and (B)

The present invention includes the following embodiments.
(1) In the invention described in Patent Document 3, a vial (= liquid feeding container) is brought into direct contact with the microfluidic chip, so that a relatively large amount of sample liquid such as a reagent is required, and the vial diameter (= liquid feeding container) The liquid feeding port diameter is much larger than the sample liquid inlet diameter. Therefore, since the sample liquid is not introduced into the sample introduction port by its own weight, a forced liquid feeding device that supplies compressed gas to the sample liquid is separately required. Furthermore, since the sample liquid is put into the vial and the compressed gas is introduced after inverting it, the liquid feeding process is complicated, and the sample liquid to be put into the vial remains at the bottom of the vial, and this is taken into account. It is necessary to put the amount of liquid. Therefore, in the invention described in Patent Document 3, the liquid feeding system to the microfluidic chip is cumbersome and leaves room for improvement.
(2) To solve the problem described in (1) above, simplify the method of feeding the sample liquid to the microfluidic chip and the liquid feeding container, that is, separately forcing the sample liquid to be fed to the microfluidic chip. It is required to provide a method and a liquid feeding container for feeding liquid without using a liquid feeding device.

(3) Configuration As a solution delivery method for solving the problem described in (2) above,
a. The gas compressed in the liquid feeding container is released, and the sample liquid is sucked into the liquid feeding container.
b. Compress the gas in the liquid delivery container.
c. By extruding the compressed gas, the sample liquid in the liquid feeding container is pressurized, and the sample liquid flows from the liquid feeding container into the sample liquid inlet of the microfluidic chip (liquid feeding).
Moreover, as a structure of a liquid feeding container, the part which accumulate | stores the release of the compressed gas used as suction force and the compressed gas used as a liquid feeding force in liquid feeding container itself is provided in the upper part of a sample liquid.
(4) Action The compressed gas used for the suction force can be used for the liquid feeding force.
(5) Effect The sample liquid is put in the liquid feeding container, and is not turned upside down, and the sample liquid is put into the liquid feeding container and the sample liquid is put into the microfluidic chip without providing a separate forced liquid feeding device. Since liquid feeding is possible, the liquid feeding method and the liquid feeding container can be simplified. Further, the compressed gas that becomes the suction force and the liquid feeding force can be sucked and pressurized with a small force of human power. In addition, in this case, since compressed gas is used to deliver liquid that can be pressurized with as little force as human power, the amount of injected liquid must be reduced. To liquid feeding to a microfluidic chip.

(6) As a detailed configuration of the liquid feeding container, a pipette provided with a gasket at the tip is used. The gasket need only be provided at least on the contact surface between the pipette tip and the sample fluid inlet of the microfluidic chip (FIG. 1), and may have a shape covering the peripheral surface of the pipette tip (FIGS. 2 and 3). ). In the example of FIG. 1, the protrusion also plays a role of receiving the reaction force of the gasket, and the gasket has a shape that is easily compressed and deformed. 2 and 3, the reaction force of the gasket is received on the side surface of the pipette tip. Since the seal surface pressure is determined by the dimensions of the gasket and the inlet, a stable surface pressure can be obtained. The microfluidic chip may be provided with a fitting groove (inlet groove). The gasket may be integrated with the pipette or may be provided on the pipette tip (resin cap).

  Next, examples of the present invention will be described.

  The liquid injection method according to the embodiment of the present invention performs the injection operation according to the following procedure.

  That is, first, a liquid such as a reagent in a sample container such as a microtube, a sample tube, a vial, a test tube, a Spitz tube, or a conical tube is aspirated and collected by a pipette tip attached to the tip of the micropipette. Next, the pipette tip is pressed against the microchannel inlet of the microchip, and the tip of the pipette tip is brought into contact with the inlet. Next, compressed gas is supplied from the micropipette body, and a liquid such as a reagent is injected and sent from the pipette tip to the microchannel in the microchip with the injection pressure of the compressed air.

  As shown in FIG. 1, a ring-shaped gasket 21 made of an elastic material such as rubber or elastomer is held around the liquid inlet / outlet 12 at the tip (lower end in the figure) of the pipette tip 11. The gasket 21 is compressed and deformed by being pressed against the microchannel inlet 32 of the microchip 31, and a reaction force due to the compressive deformation is generated in the gasket 21. Thus, the present invention effectively utilizes the reaction force generated in the gasket 21 as described above. That is, since this reaction force counters the injection pressure caused by the compressed gas during liquid injection, the liquid leaks to the outside. Instead, it is introduced into the microchannel 33 from the pipette tip 11 through the microchannel inlet 32.

  As shown in the drawing, the gasket 21 is attached to the tip of the pipette tip 11 by providing a protrusion 13 for receiving the gasket on the outer periphery of the tip of the pipette tip 11, and a step 14 provided on the tip side of the protrusion 13 as an axial receiving portion. The gasket 21 separately molded in advance is fitted together, but the gasket 21 may be directly integrally formed at the tip of the pipette tip 11 as shown in FIG. 2 or FIG.

  Further, as shown in FIG. 1, when the diameter of the microchannel inlet 32 is smaller than the inner diameter of the gasket 21, the gasket 21 is pressed against the upper surface 31a of the microchip 31 at the opening peripheral edge of the microchannel inlet 32. The gasket 21 is arranged so as to protrude from the tip of the pipette tip 11 in the tip direction (downward in the figure). The gasket 21 in FIG. 1 has an O-ring shape with a circular cross section, and the tip portion that protrudes from the tip of the pipette tip 11 toward the tip and presses against the upper surface 31a of the microchip 31 forms a lip 22 having an arcuate cross section. When pressed against the upper surface 31a of the microchip 31, the contact surface pressure (seal surface pressure) has a peak value due to the arc tip (lip tip). Therefore, since the gasket 21 is provided with the lip 22 having an arcuate cross section in this way, it has excellent sealing performance as compared with a planar gasket without a lip.

  As shown in FIG. 2, when the diameter of the microchannel inlet 32 is larger than the inner diameter of the gasket 21, the gasket 21 is inserted into the microchannel inlet 32 together with the tip of the pipette tip 11 and the inner surface of the microchannel inlet 32 Since the gasket 21 is pressed against the side surface 32a, the gasket 21 does not need to protrude from the tip of the pipette tip 11 toward the tip, and protrudes only outward in the radial direction. The gasket 21 in FIG. 2 has a semicircular cross section, and the outer peripheral portion that protrudes radially outward and is pressed against the inner surface 32a of the microchannel inlet 32 forms a lip 22 having an arcuate cross section. When pressed against the inner surface 32a of the port 32, the peak value due to the arc tip (lip tip) is set in the contact surface pressure (seal surface pressure). Therefore, since the gasket 21 is provided with the lip 22 having an arcuate cross section in this way, it has excellent sealing performance as compared with a planar gasket without a lip. Further, as shown in FIG. 3, a projection 15 for pressing the gasket 21 against the inner surface 32 a of the microchannel inlet 32 may be provided on the outer periphery of the tip of the pipette tip 11.

  The pipette tip 11 is produced by an injection molding method or the like using a thermoplastic resin as a molding material in the same manner as a commercially available one. On the other hand, the material of the gasket 21 made of rubber or elastomer is selected depending on the material of the pipette tip 11 and the type of liquid, but representative examples include silicone rubber, fluororubber, acrylic rubber, nitrile rubber, butyl rubber, and the like. It is done. The molding method of the gasket 21 is a compression molding method or an injection molding method.

  Moreover, in the said Example, it was set as the structure which hold | maintains the gasket 21 in the front-end | tip part of the pipette chip | tip 11, However, instead of this, it is good also as a structure hold | maintained on the film body 41 which temporarily fixes the gasket 21 to the microchip 31, The embodiment in this case will be described below.

  That is, as shown in FIG. 4, a film body 41 that is detachably attached to the upper surface of the microchip 31 is prepared, an adhesive (not shown) is applied to the lower surface of the film body 41, and the film body 41 is A ring-shaped gasket 21 is fixed to the upper surface by means such as adhesion. As the film body 41, it is preferable to use a flexible resin film.

  The gasket 21 is provided in a state where the film body 41 is adhered to the upper surface of the microchip 31, and the microchannel inlet 32 opened on the upper surface of the microchip 31 is aligned with the position on the plane. When a plurality of microchannel inlets 32 are opened, the same number of gaskets 21 are provided in accordance with the positions of the inlets 32.

  Further, as shown in the cross section of FIG. 5, the film body 41 is connected to the inner circumferential space of the gasket 21 and the microchannel inlet 32 in a state where the film body 41 is adhered to the upper surface of the microchip 31. A through hole 42 is provided.

  With the above configuration, the gasket 21 can also be referred to as a film-integrated gasket with an adhesive, and as a configuration of the film-integrated gasket with an adhesive, an adhesive is formed on one side of the film body 41, and the opposite surface. Further, a gasket 21 made of an elastic body of rubber or elastomer is formed. The gasket 21 has a hole in the center like an O-ring or the like, and this hole reaches the microchannel inlet 32 through a through hole 42 provided in the film body 41. The inner diameter of the gasket 21 is set smaller than the outer diameter of the tip of the pipette tip 11, so that the pipette tip 11 is press-fitted into the inner periphery of the gasket 21.

  As described above, the microchip 31 may have a plurality of microchannel inlets 32 opened. According to the configuration of the present invention, the microchip 31 can be formed by simply attaching the film body 41 to the microchip 31. The gasket 21 can be positioned with respect to the introduction port 32. When injecting a liquid such as a reagent, the pipette tip 11 is brought into contact and the gasket 21 is compressed. Therefore, the microchip 31 and the film body 41 do not need to be firmly bonded, and the gasket 21 may be positioned.

  As for the form of the film body 41, the planar shape of the film body 41 is the same shape and size as the upper surface of the microchip 31 as in the above embodiment, and one film body 41 covers the entire upper surface of the microchip 31. In addition to the mode in which the plurality of gaskets 21 and the through holes are provided corresponding to the plurality of inlets 32 on the microchip 31 with the one film body 41, a plurality of film bodies 41 are used in combination. Also good.

  In this case, the film body 41 has a size that is slightly larger than the gasket 21, the same number of film bodies 41 as the introduction ports 32 are prepared, and one gasket 21 and one through hole 42 are provided per sheet. 14 is affixed to each inlet 32. In addition, when there are three or more introduction ports 32, they may be grouped (for example, when there are four introduction ports 32, the first film body 41 with respect to the first and second introduction ports 32). The first and second gaskets 21 are disposed, and the third and fourth gaskets 21 are disposed with respect to the third and fourth inlets 32 by the second film body 41).

DESCRIPTION OF SYMBOLS 11 Pipette tip 12 Liquid inlet / outlet 13,15 Protrusion 14 Step part 21 Gasket 22 Lip 31 Microchip 32 Microchannel inlet 33 Microchannel 41 Film body 42 Through-hole

Claims (5)

A step of aspirating and collecting the liquid contained in the sample container with a micropipette or a pipette tip attached to the tip of the micropipette, a step of pressing the micropipette or the pipette tip against a microchannel inlet of the microchip, Sequentially injecting and feeding the liquid from the micropipette or the pipette tip to the microchannel by a compressed gas supplied from a pipette;
The liquid to be injected / delivered from the micropipette or the pipette tip to the microchannel is sealed with an elastic gasket, and the gasket is compressed when the micropipette or the pipette tip is pressed against the microchannel inlet. A method for injecting a liquid into a microchannel, wherein the gasket generates a reaction force that can counteract the liquid injection pressure by deforming the gasket. The liquid injection method according to claim 1,
The method for injecting a liquid into a microchannel, wherein the gasket is held in advance at the tip of the micropipette or the pipette tip. The liquid injection method according to claim 1,
The method of injecting liquid into a microchannel, wherein the gasket is held in advance by a film body temporarily fixed to the microchip. A micropipette or pipette tip used for carrying out the liquid injection method according to claim 2,
A micropipette or pipette tip characterized in that a gasket is held at its tip. A film body used for carrying out the liquid injection method according to claim 3,
A pressure-sensitive adhesive is applied to one surface in the thickness direction, a gasket is held on the other surface in the thickness direction, and a through-hole that communicates the inner circumferential space of the gasket and the microchannel inlet is provided. A film body.

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