JP2007263706A - Microchip for bioassay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microchip for a bioassay with a reactive substance sealed in its analysis part, using simple operations for performing analysis with a stable detection level. <P>SOLUTION: This microchip X for a bioassay comprises a microchip body A provided with a fluid passage 10, where specimen liquid holding a measuring substance flows down and the analysis part 20 in the fluid passage 10 for analyzing the liquid sample. This microchip X is equipped with a plug member 30 insertable into the microchip body A and used for sealing the reactive substance that reacts with the measuring substance in the analysis part 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bioassay microchip for detecting a measurement substance contained in a liquid sample.

Conventionally, an analyzer for analyzing a liquid sample containing a biological substance such as a nucleic acid, a protein, or a microbial cell as a measurement substance is known. The analysis unit provided in the analyzer detects the measurement substance contained in the liquid sample using, for example, an immunological technique based on an antigen-antibody reaction or a biochemical technique based on hybridization of a nucleic acid or the like. Therefore, an immobilizing substance such as a bead carrying a binding substance that binds to the measurement substance to form a specific complex is arranged in the analysis unit.
The binding substance is an example of a reactive substance that reacts with the measurement substance.

  Patent Document 1 describes that an estrogen receptor, which is a binding substance, is immobilized on the surface of an immobilization substance and is stacked on an analysis unit of an analyzer. The immobilized substance on which the reactive substance is immobilized is transferred to the analysis unit while being contained in the suspension.

In recent years, microchips manufactured by applying microfabrication technology (MEMS) such as semiconductors are widely used in fields such as biochemistry and medicine.
The microchip is constructed by stacking two substrates of several centimeters in length and breadth. In these substrates, there are sample injection holes, sample discharge holes, minute capillary fluid flow paths, or analysis sections such as chambers, electrophoresis columns, membrane separation mechanisms as analysis areas connected to the flow paths. It is formed.

The immobilization substance can be sealed in the analysis part by accommodating the immobilization substance carrying the reactive substance in a portion corresponding to the analysis part of one substrate of the microchip and stacking the other substrate.
On the other hand, as another method for encapsulating the immobilized substance in the analysis unit, Patent Document 2 discloses that the immobilized substance carrying a nucleic acid that is a reactive substance is transferred by a gel until it is seized at the end of the analysis unit. It is described.

Japanese Patent No. 348246 JP 2005-127771 A

  In the analysis section, for example, several hundreds of immobilization substances on which reactive substances are immobilized are sealed. For example, when detecting a trace amount of a measurement substance, if the microchip lot is different, the detection level of the measurement substance varies depending on the number of the immobilized substances sealed in the analysis unit.

Further, when the reactive substance is immobilized on the surface of the immobilizing substance, the fixing density of the reactive substance on the surface of the immobilizing substance becomes non-uniform depending on the contact state between the laminated immobilizing substances. Furthermore, when the immobilized substance with the reactive substance immobilized is transferred to the analysis section by a solution or gel, the immobilized reactive substance may fall off the surface of the immobilized substance due to contact between the immobilized substances. is there.
In these cases also, the detection level of the measurement substance varies.

  Accordingly, an object of the present invention is to provide a microchip for bioassay in which a reactive substance can be enclosed in an analysis section with a simple operation and analysis can be performed with a stable detection level.

  In order to achieve the above object, a microchip for bioassay according to the present invention is provided with a fluid channel through which a liquid sample containing a measurement substance flows, and an analysis unit for analyzing the liquid sample in the fluid channel. A microchip for bioassay having a microchip body, the first characteristic configuration of which is a plug member that can be inserted into the microchip body and encloses a reactive substance that reacts with the measurement substance in the analysis unit It is in the point prepared.

According to said 1st characteristic structure, a reactive substance can be directly enclosed with an analysis part with a plug member. For this reason, unlike the conventional microchip, there is no need to transfer the immobilization substance on which the reactive substance is immobilized to the analysis section by a solution or gel, and the operation of sealing the reactive substance in the analysis section is simple.
Further, unlike the conventional microchip, the reactive substance is not encapsulated in the analysis part in a state where a part of the reactive substance is lost, and a desired amount of the reactive substance can be reliably encapsulated. The detection level is stable.

  The second characteristic configuration of the microchip for bioassay according to the present invention is that the reactant is fixed to the plug member.

  According to said 2nd characteristic structure, a reactive substance can be enclosed with an analysis part by very simple operation of inserting only the plug member which has fixed the reactive substance in a microchip main body.

  Moreover, since a reactive substance can be normally enclosed in an analysis part by one plug member with respect to one microchip main body, handling property improves.

  A third characteristic configuration of the microchip for bioassay according to the present invention is that the degree of insertion of the plug member into the analysis unit can be set freely.

  According to the third characteristic configuration, the insertion depth of the plug member can be appropriately set according to the degree of pushing of the plug member, so that the volume of the analysis unit can be easily set as appropriate. Therefore, it is not necessary to manufacture many types of plug members. Therefore, the manufacturing cost of the plug member can be reduced.

  The fourth characteristic configuration of the microchip for bioassay according to the present invention is such that the plug member has a cross-sectional area perpendicular to the direction of insertion into the analysis portion, with the tip on the insertion direction side being smaller than the end with respect to the insertion direction. In the point.

  According to the fourth feature configuration, the degree of insertion of the plug member into the microchip body can be defined by the shape of the plug member, so that the pushing operation of the plug member is easy and the insertion of the plug member is completed. Can be easily recognized.

  A fifth characteristic configuration of the microchip for bioassay according to the present invention is such that at least one of the upstream and downstream fluid flow paths adjacent to the analysis unit is parallel to the flow path direction of the fluid flow path. It has a groove.

According to the fifth characteristic configuration described above, when a plurality of grooves are provided upstream adjacent to the analysis unit, the liquid sample passes between the grooves and flows into the analysis unit. It is easy to flow downward uniformly. For example, when an immobilization substance carrying a reactive substance that reacts with a measurement substance is sealed in the analysis unit, the immobilization substance and the liquid sample efficiently contact each other.
On the other hand, when a plurality of grooves are provided downstream from the analysis unit, the liquid sample can pass between the plurality of grooves and flow out of the analysis unit without stagnation. Therefore, when the immobilizing substance is sealed, the liquid sample can be circulated upward and downward for almost all of the immobilizing substance.

Embodiments of the present invention will be described below with reference to the drawings.
The present invention is a microchip for bioassay (hereinafter referred to as a microchip) for detecting a measurement substance contained in a liquid sample.
A microchip is a kind of so-called biochip.
The microchip is connected to, for example, an injection part for injecting a liquid such as a liquid sample into a substrate, a discharge part for discharging the liquid, a minute capillary fluid flow path through which the liquid flows, and the fluid flow path. An analysis unit such as a chamber, an electrophoresis column, and a membrane separation mechanism is formed as an analysis region. Such a microchip is mainly used for detecting a measurement substance contained in a liquid sample, such as a DNA analysis device, a microelectrophoresis device, a microchromatography device, and a microsensor.

1-4 show the microchip X of this embodiment.
The microchip X in the present embodiment includes a microchip body A in which a fluid channel 10 in which a liquid sample containing a measurement substance flows down and an analysis unit 20 that analyzes the liquid sample in the fluid channel 10 are provided. A plug member 30 that can be inserted into the microchip body A and encloses a reactive substance that reacts with the measurement substance in the analysis unit 20 is provided.

(Microchip body)
The microchip body A uses, for example, a glass plate that can be obtained at a low cost and has excellent chemical resistance as a constituent material. In addition to glass, a quartz plate, silicon resin such as polydimethylsiloxane (PDMS), acrylic resin, or the like can be used as a constituent material of the microchip body A. In the present embodiment, a microchip body A using an acrylic resin substrate as a constituent material is illustrated.

The microchip body A is configured by stacking two substrates. By bringing the flat substrate 4 into contact with one substrate 3 in which the recesses and grooves are finely processed, structures such as a fluid flow path and an analysis unit can be formed.
Examples of the method for directly performing microfabrication on the substrate include mechanical cutting using a micromachining drill, ionizing radiation lithography such as photolithography or AFM lithography, and methods using physical and chemical etching. The
On the other hand, as a method of indirectly performing microfabrication on a substrate, it is possible to use a method of transferring a micro structure using a mold corresponding to a desired structure.

  As shown in FIG. 1, the microchip body A includes an injection part 1, a discharge part 2, a fluid flow path 10, and an analysis part 20.

The injection part 1 and the discharge part 2 of this embodiment are configured by inserting pipe members 1a and 2a into the substrate 3, respectively. For example, the liquid sample can be supplied to the microchip body A via the silicon tube by connecting the pipe member 1a to the silicon tube.
However, the present invention is not limited to this, and holes serving as the injection part 1 and the discharge part 2 may be formed in the substrate 4.
The fluid flow path 10 and the analysis unit 20 are spaces surrounded by the substrates 3 and 4.

The analysis unit 20 in the present embodiment exemplifies analysis means using an immunological technique based on an antigen-antibody reaction as a binding pair assay. However, the present invention is not limited to this, and analytical means using a biochemical technique by hybridization of a known nucleic acid or the like can also be applied.
In the case of the analysis unit 20 using an immunological technique, the analysis unit 20 is configured to enclose a binding substance that binds to a measurement substance contained in a liquid sample to form a specific complex. In the present embodiment, a binding substance that captures the measurement substance will be described as a substance used when detecting the measurement substance. However, the present invention is not limited to this. For example, any reactive substance that reacts with the measurement substance and capable of detecting and quantifying the measurement substance may be used.

By immobilizing the binding substance on the surface of the member forming the analysis unit 20, or by enclosing the immobilization substance in the analysis unit 20 in a state where the binding substance is supported on the surface of the immobilization substance, A binding substance can be arranged in the analysis unit 20.
In the present invention, the binding substance is arranged in the analysis unit 20 by the plug member 30 described below.
In the microchip body A, a plug insertion portion 5 for inserting the plug member 30 is provided at a location corresponding to the analysis portion 20. In this embodiment, the plug insertion portion 5 is provided on the substrate 3. The plug insertion part 5 is a hole having a shape corresponding to the shape of the plug member 30 in the insertion direction. When the plug member 30 is not inserted, the analysis part 20 is exposed.

(Plug member)
The plug member 30 can be inserted into the microchip body A, and encloses a binding substance (reactive substance) that reacts with the measurement substance in the analysis unit 20. Thereby, the binding substance can be directly enclosed in the analysis unit 20 by the plug member 30. For this reason, unlike the conventional microchip, there is no need to transfer the immobilized substance having the binding substance immobilized to the analysis part by a solution or gel, and the operation of sealing the binding substance in the analysis part is simple.
Further, unlike the conventional microchip, the binding substance is not sealed in the analysis unit 20 in a state where a part of the binding substance is lost, and a desired amount of binding substance can be reliably sealed, and the measurement substance The detection level of becomes stable.

The analysis unit 20 is sealed by inserting the plug member 30 into the plug insertion unit 5. For this reason, the front end surface 31 where the plug member 30 faces the analysis unit 20 becomes a part of the member forming the analysis unit 20.
The plug member 30 may be inserted into the microchip body A from any direction from above or from below. In this embodiment, since the plug insertion part 5 is provided in the board | substrate 3, the case where the plug member 30 is inserted in the plug insertion part 5 from the downward direction is illustrated. When the plug member 30 is inserted into the plug insertion portion 5 from above, the plug insertion portion 5 may be provided on the substrate 4.

The plug member 30 has a binding substance fixed on the surface thereof.
At this time, the binding substance can be sealed in the analysis unit 20 by an extremely simple operation of inserting the plug member 30 to which the binding substance is fixed into the microchip body A. In this embodiment, since the binding substance can be sealed in the analysis unit by one plug member 30 for one microchip main body A, the handling property is improved.

  The plug member 30 can be applied as long as it is a water-insoluble substance that can fix the binding substance. Examples thereof include a carrier made of a polymer such as latex, polyethylene, polystyrene, and polypropylene, a silicic acid inorganic carrier (glass, silica gel, etc.), an organic carrier (plastic, nitrocellulose, dextran, etc.), and the like.

  In particular, when the plug member 30 and the microchip body A are selected to have different elasticity, when the plug member 30 is inserted into the microchip body A, one of these two members is the other. It becomes easier to elastically deform than this member. Therefore, the adhesion degree of each member increases and watertightness improves.

  When the plug member 30 is configured to have the small diameter portion 30a and the large diameter portion 30b as shown in FIG. 2, the small diameter portion 30a and the large diameter portion 30b may be configured to have different elasticity. . At this time, the small-diameter portion 30a and the large-diameter portion 30b have different degrees of adhesion to the microchip body A. Therefore, since either one of the small-diameter portion 30a and the large-diameter portion 30b can be configured to be in close contact with the microchip body A, it is easy to ensure water tightness between the plug member 30 and the microchip body A.

A method for fixing the binding substance to the immobilization substance can be performed by a known method. For example, a method of physically adsorbing an antibody (binding substance) to the plug member 30 or a sensor provided on the surface of the plug member 30 is used. There is a method of covalently bonding an amino group or the like of a “binding substance” to a group. After the binding, the surface of the carrier and the unreacted functional group on the surface can be blocked with an appropriate protein / surfactant or the like to suppress nonspecific reactions.

For example, when the antibody is physically adsorbed to the plug member 30 made of polystyrene carrier, the plug member 30 is immersed in a solution in which the antibody is dissolved, and is gently shaken overnight, so that the entire surface of the plug member 30 is obtained. Immobilize the antibody. At this time, since a small number of plug members of about 1 to several are handled, the handling is simpler than the case of handling a large number of beads.
Further, since the handling is small, it is easy to prevent the fixing density of the binding substance immobilized on the surface from becoming non-uniform by stacking the plug part 30 members. Therefore, the detection level of the measurement substance is difficult to change.

  In addition, when the plug member 30 is inserted into the microchip body A, when only the distal end surface 31 faces the analysis unit 20, the antibody may be adsorbed only on the distal end surface 31.

The degree of insertion of the plug member 30 into the analysis unit 20 is configured to be freely set.
Specifically, as shown in FIG. 3, the plug member 30 is formed in a cylindrical shape. At this time, the outer diameter of the plug member 30 is set so that the plug member 30 and the plug insertion portion 5 are in close contact with each other when inserted into the plug insertion portion 5. Therefore, the plug member 30 is securely inserted into the plug insertion portion 5.
At this time, since the plug member 30 has a cylindrical shape, the distance for inserting the plug member 30 into the plug insertion portion 5 can be appropriately changed depending on the degree of pushing of the plug member 30, thereby setting the degree of insertion of the plug member 30. it can.

For example, when the plug member 30 is inserted into the microchip body A, the height of the front end surface 31 of the plug member 30 can be made substantially coincident with the bottom surface of the fluid flow path 10. If the level between these members is substantially the same, the liquid sample can flow down the analyzer 20 without stagnation.
Further, when the plug member 30 is inserted into the microchip body A, the height of the distal end surface 31 of the plug member 30 can be set lower than the bottom surface of the fluid flow path 10. Thereby, since the analysis part 20 can be made to have a recessed part, carriers, such as a bead, can be arrange | positioned to this recessed part.
Therefore, since the insertion depth of the plug member 30 can be set as appropriate according to the degree of pushing of the plug member 30, it is easy to set the volume of the analysis unit 20 as appropriate. Therefore, it is not necessary to manufacture many types of plug members. In addition, since the shape and volume of the analysis unit 20 can be changed as appropriate, a wide range of analysis conditions in the analysis unit 20 can be set.

The cross-sectional area perpendicular to the insertion direction of the plug member 30 in the analysis unit 20 can be configured such that the distal end 32 on the insertion direction side is smaller than the distal end 33 with respect to the insertion direction.
For example, the plug member 30 shown in FIG. 2 includes a small diameter portion 30a and a large diameter portion 30b. At this time, the plug member 30 has a shape with a stepped outer surface, and the plug member 30 stops being inserted into the microchip body A by the large diameter portion 30b coming into contact with the plug insertion portion 5 of the substrate 3.
Further, the plug member 30 shown in FIG. 4 has a tapered portion 30c on the side surface. At this time, the taper portion 30c abuts against the plug insertion portion 5, whereby the plug member 30 stops inserting into the microchip body A.
Thus, since the degree of insertion of the plug member 30 into the microchip body A can be defined by the shape of the plug member 30, the pushing operation of the plug member 30 is easy, and the insertion operation of the plug member 30 is completed. Can be easily recognized.

  Here, for example, when the large-diameter portion 30 b is securely held by the plug insertion portion 5, the small-diameter portion 30 a may be configured not to contact the plug insertion portion 5. At this time, a gap is formed between the small diameter portion 30 a and the plug insertion portion 5. This gap can be used as a part of the analysis unit 20. That is, if an antibody is fixed to the distal end surface 31 of the plug member 30 and the outer surface of the small diameter portion 30, even a very small amount of measurement substance can be detected with high sensitivity.

(Details of liquid sample and analysis method)
The above-mentioned “liquid sample” refers to a liquid sample containing or possibly containing a measurement substance to be analyzed. The liquid sample may be from any source. For example, it can be obtained from environmental samples, cells, cultures, tissues, body fluids, urine, serum and biopsy samples.
Examples of environmental samples include soil collected from factory sites, water collected from rivers, and the like. Then, the sample collected from the environment is adjusted so as to be a liquid sample having a viscosity that can flow down through the flow path formed in the microchip.

The “measurement substance” contained in the liquid sample is captured by the binding of this measurement substance and a binding substance (described later) that can form a specific conjugate. The specific complex is the result of the binding pair assay. As described later, the immunochemical complex resulting from the antigen-antibody reaction, the complex resulting from the hybridization of complementary nucleic acids, etc. Is preferably exemplified.
In this embodiment, the binding substance that captures the measurement substance is described as the substance used when detecting the measurement substance. However, the present invention is not limited thereto, and for example, a reactive substance that reacts with the measurement substance, Any substance capable of detecting and quantifying the measurement substance may be used.

  The measurement substance can be any substance such as chemical substances, polymers such as proteins, DNA fragments, microorganisms or viruses, fragments thereof, hormones, and the like. Examples of the measurement substance applicable to the microchip of the present invention include substances that can cause environmental pollution such as toxic substances (PCB, dioxin) and oily substances (heavy oil) contained in soil, or river water. Preferred examples include pathogenic Escherichia coli cells.

“Binding substance” means a substance capable of recognizing a measurement substance, that is, a substance having molecular recognition ability capable of selectively detecting a measurement substance having an affinity for a binding substance. Specific examples include nucleic acids such as antigens, antibodies, DNA fragments, oligonucleotides, polynucleotides, peptide nucleic acids, proteins, peptides, sugars, cells, microorganisms, and the like, but are not limited thereto.
Examples of molecular discriminating ability include, for example, the ability to hybridize (complementary binding) between antibody / antibody fragment-antigen and between nucleic acids, or regulatory factor / receptor-hormone / cytokine / neurotransmitter / lectin. A biological response ability between the enzyme and the substrate-coenzyme or the like is preferably exemplified.
For example, the binding substances for PCB and dioxin as measurement substances are an anti-PCB antibody and an anti-dioxin antibody, respectively.

  As the “immunochemical technique”, for example, the presence of a measurement substance in a liquid sample can be detected or quantitatively measured by applying an immunoassay technique based on a solid phase method. In the so-called “sandwich method” known as an immunoassay, for example, a target measurement substance such as an antigen is sandwiched between a labeled antibody and an antibody (binding substance) immobilized on the surface of the immobilized substance, The analysis unit 20 can form a specific complex and capture the measurement substance.

Thus, the presence of the measurement substance can be detected or quantitatively measured by labeling the antibody or the like forming a specific complex. Note that either the measurement substance or the binding substance may be labeled.
In this way, the measurement substance in the liquid sample can be detected with high sensitivity.

The specific complex formed by the antigen-antibody reaction is detected as follows.
For example, by labeling an antibody with a fluorescent (luminescent) substance and detecting its fluorescence (luminescent) intensity directly, or by binding an enzyme to the antibody and performing an enzymatic reaction using a chemiluminescent substrate, optical changes can be detected. To do.

As a result of the reaction when a fluorescently labeled antibody is used, a labeling substance is present in the specific complex produced depending on the amount of “measurement substance”. A “measurement substance” can be quantified by introducing a washing buffer or the like from the injection section 1 to flow down the fluid flow path 10 to remove unreacted substances and then measuring the amount of the labeling substance. The quantification of the labeling substance can take various methods along with the type of the labeling substance. For example, the fluorescence intensity of the fluorescent substance is measured by a fluorescence measuring device. By comparing the measured label intensity with the label intensity when a known amount of “measurement substance” is measured, the amount of the measurement substance in the liquid sample can be determined.

[Another embodiment]
In the above-described embodiment, the case where the binding substance is fixed to the plug member 30 has been described.
However, the present invention is not limited to this, and a binding substance is fixed to an immobilization substance such as a fine bead, and the plug member 30 is used as a member that encloses the beads 40 carrying the binding substance on the surface thereof in the analysis unit 20. (FIG. 5).

  When the beads 40 are arranged in the analysis unit 20 as in the present embodiment, the recesses 6 for accommodating the beads 40 are provided. For example, in the case of the cylindrical plug member 30 described above (FIG. 3), the recess 6 can be formed by stopping the insertion of the plug member 30 into the plug insertion portion 5 in the middle.

When the recess 6 is provided in this way, the bead 40 can be reliably held in the analysis unit 20. However, as compared with the flat analysis unit 20, the analysis unit 20 constituted by the recess 6 is liable to cause liquid stagnation. Therefore, when the washing buffer or the like is caused to flow down inside the analysis unit 20, there is a possibility that sufficient washing cannot be performed.
Therefore, a plurality of grooves parallel to the flow path direction of the fluid flow path 10 are provided in at least one of the upstream and downstream fluid flow paths 10 adjacent to the analysis unit 20.

For example, the groove portion 11 including a plurality of grooves 11 a is provided upstream of the recess 6.
Since a part of the liquid sample passes between the plurality of grooves 11a, the liquid sample easily flows uniformly above and below the recess 6 of the analysis unit 20. Therefore, the bead 40 carrying the binding substance and the liquid sample efficiently contact each other.

Similarly, a groove portion 12 including a plurality of grooves 12 a is provided downstream of the recess portion 6. As a result, the liquid sample can pass between the plurality of grooves 12a and flow out of the analysis unit 20 without stagnation. At this time, the liquid sample can be circulated upward and downward for almost all the beads 40.
The interval between the plurality of grooves 12a is appropriately selected so that the beads 40 do not pass between the groove parts 12a and flow out downstream of the analysis part 20 when the liquid sample flows down the fluid flow path 10.

In order to enclose the bead 40 carrying the binding substance in the analysis unit 20, the bead 40 may be disposed in the analysis unit 20, and then the plug member 30 may be inserted into the plug insertion unit 5.
In this configuration, when the binding substance is sealed in the analysis unit 20, the bead 40 carrying the binding substance does not flow down the fluid flow path 10, so that the binding substance fixed to the surface of the bead 40 is not present. There is no risk of peeling from the surface of the bead 40. Therefore, the detection level of the measurement substance is stabilized.

The immobilization substance may take various forms such as a sheet form and a tube form in addition to the bead-like particles. Preferable examples are beads having a particle size of about 0.1 to 1000 μm, preferably about 1 to 100 μm, and particularly preferably about 1 to 50 μm.
On the other hand, porous materials such as nylon, nitrocellulose, cellulose acetate, glass fiber and porous polymer can be used as the immobilizing material.

  As the “immobilization substance”, any water-insoluble substance that can carry a binding substance on its surface can be applied. For example, carriers made of polymers such as latex, polyethylene, polystyrene, polypropylene, inorganic silicate carriers (glass, silica gel, etc.), organic carriers (plastic, nitrocellulose, dextran, etc.), carbon materials such as activated carbon, metal particles, Examples thereof include a magnetic material such as magnetite.

  The present invention can be used for a microchip for detecting a measurement substance contained in a liquid sample.

Schematic diagram of the microchip for bioassay of the present invention Schematic diagram of plug member to be inserted into analysis unit Schematic of another aspect of the plug member inserted into the analysis unit Schematic of another aspect of the plug member inserted into the analysis unit Schematic of the analysis unit periphery of another embodiment

Explanation of symbols

X Microchip A Microchip body 10 Fluid flow path 11a, 12a Groove 20 Analysis unit 30 Plug member

Claims (5)

A biochip microchip having a microchip body provided with a fluid channel through which a liquid sample containing a measurement substance flows down and an analysis unit for analyzing the liquid sample in the fluid channel,
A microchip for bioassay comprising a plug member that can be inserted into the microchip body and encloses a reactive substance that reacts with the measurement substance in the analysis unit.   The bioassay microchip according to claim 1, wherein the reactant is fixed to the plug member.   The microchip for bioassay according to claim 1 or 2, wherein the degree of insertion of the plug member into the analysis unit is freely settable.   The bio according to any one of claims 1 to 3, wherein a cross-sectional area perpendicular to the insertion direction of the plug member in the analysis unit is configured such that a tip on the insertion direction side is smaller than a terminal with respect to the insertion direction. Microchip for assay.   5. The groove according to claim 1, wherein a plurality of grooves parallel to the flow direction of the fluid flow path are provided in at least one of the upstream and downstream fluid flow paths adjacent to the analysis unit. Microchip for bioassay.

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