Flow channel device

Abstract

The present invention provides a flow channel device capable of detecting a chemical substance diffusing from an inside to an outside of a flow channel. The flow channel device comprises: a flow channel forming section including a flow channel formed of a first hydrogel; a detection section disposed so as to oppose the flow channel of the flow channel forming section; and a diffusion layer formed of a second hydrogel and sandwiched between the flow channel forming section and the detection section. The flow channel forming section includes a base material and a gel layer which is formed of the first hydrogel as a forming material and is provided on an upper surface of the base material. At an interface between the base material and the gel layer are formed an adhesion region where the base material and the gel layer adhere to each other and a non-adhesion region where the base material and the gel layer do not adhere to each other. In the non-adhesion region, the gel layer is separated from the base material to form a flow channel surrounded by the gel layer and the base material. The detection section has an opposing base material and a sensor provided at an interface between the opposing base material and the diffusion layer.

Description

Flow Channel Devices

[0001] The present invention relates to a flow path device.

[0002] In recent years, in drug discovery research aimed at treating diseases and research into the mechanisms of disease onset, attempts have been made to mimic biological functions and structures in vitro using microfluidic chips. One known example of such an attempt is the construction of a model system known as a biomimetic system (hereinafter abbreviated as "MPS"). Microfluidic chips are widely used in MPS. The substrate used for MPS is made of a material that allows cell culture and is easily moldable. Examples of such materials include glass, polymethyl methacrylate (PMMA), and polydimethylsiloxane (PDMS).

[0003] Meanwhile, in MPS, it is necessary to evaluate the effects of oral drugs and understand the dynamics of infectious disease and disease-causing substances as they act on diseased areas. To achieve this, it is necessary to evaluate the diffusion and effects of drugs and causative substances that reach the site of action in biological tissues from the circulatory system, including blood vessels. Materials used in conventional microfluidic devices have low substance permeability and are not suitable for the above purposes. Therefore, materials suitable for these purposes are needed.

[0004] To achieve the above objectives, it is known that hydrogels with high substance permeability and biocompatibility are effective. Microfluidic devices using hydrogels, for example, are known that have a three-dimensional structure resulting from the free swelling of the hydrogel in the non-adhesive regions, with adhesive / non-adhesive regions between a solid substrate and a swelling gel arranged in a pattern (see, for example, Patent Document 1). Hydrogel channel-type devices that utilize three-dimensional structures as flow channels are also known (see, for example, Patent Document 2). Furthermore, hydrogel channel-type devices are known to be useful as substance-permeable microfluidic devices for dye diffusion from channels, cell culture on hydrogel channel-type devices, and drug stimulation of cells (see, for example, Non-Patent Document 1).

[0005] JP 2020-62843 A International Publication No. 2021 / 079399

[0006] “Tough, permeable and biocompatible microfluidic devices formed through the buckling delamination of soft hydrogel films”,Riku Takahashi,et al., The Royal Society of Chemistry 2021,Lab Chip,2021,21,1307-1317

[0007] In the permeation of substances through hydrogel channel-type devices, the use of dyes has been essential to visualize the diffusion of substances into the device over time. However, when performing pharmacodynamic analysis using MPS or measuring the dynamics of disease-causing substances, it is often impossible to visualize the target drug or causative substance (hereinafter referred to as "analyte"). One method for visualizing analytes is to modify the analyte with a labeling agent (e.g., fluorescent dye, nanoparticles). However, this method has drawbacks, such as being cumbersome and the high possibility that modification with a labeling agent will change the permeability and diffusion rate of the target substance.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a flow path device that can create a tissue-like structure that simulates the biological environment on a chip outside the body, and that can measure molecular diffusion from inside the structure to outside the structure via a blood vessel-like tubular structure.

[0009] In order to solve the above-mentioned problems, one aspect of the present invention provides a flow path device capable of detecting chemical substances diffusing from within a flow path to outside the flow path, the flow path device comprising: a flow path forming portion having the flow path formed from a first hydrogel; a detection portion arranged opposite the flow path of the flow path forming portion; and a diffusion layer formed from a second hydrogel and sandwiched between the flow path forming portion and the detection portion, the flow path forming portion having a substrate and a gel layer formed from the first hydrogel and provided on an upper surface of the substrate, the interface between the substrate and the gel layer having an adhesion region where the substrate and the gel layer are adhered and a non-adhesion region where the substrate and the gel layer are not adhered, the gel layer is separated from the substrate in the non-adhesion region, forming the flow path surrounded by the gel layer and the substrate, and the detection portion has an opposing substrate and a sensor provided at the interface between the opposing substrate and the diffusion layer.

[0010] According to the present invention, it is possible to create a tissue-like structure that simulates the biological environment on a chip outside of a living body, and to provide a flow path device that can measure molecular diffusion from inside the structure to outside the structure via a blood vessel-like tubular structure.

[0011] Fig. 1 is a schematic perspective view of a flow channel device 1 according to an embodiment. Fig. 2 is a cross-sectional view of the flow channel device 1 taken along line II-II in Fig. 1 . Fig. 3 is a cross-sectional view of the flow channel device 1 taken along line III-III in Fig. 1 . Fig. 4 is an explanatory diagram showing a method for detecting analyte A using the flow channel device 1. Fig. 4 is an explanatory diagram showing a method for detecting analyte A using the flow channel device 1.

[0012] The flow channel device according to this embodiment will be described below with reference to Figures 1 to 5. In all of the following figures, the dimensions and proportions of the components are appropriately changed to make the drawings easier to understand.

[0013] In the following explanation, an xyz Cartesian coordinate system is set, and the positional relationships of the components are explained with reference to this xyz Cartesian coordinate system. Here, a predetermined direction in a horizontal plane is defined as the x-axis direction, a direction perpendicular to the x-axis direction in the horizontal plane is defined as the y-axis direction, and a direction perpendicular to both the x-axis and y-axis directions (i.e., the vertical direction) is defined as the z-axis direction.

[0014] Furthermore, "up" refers to the +z direction, which is vertically upward, and "down" refers to the -z direction, which is vertically downward.

[0015] In the following description, "planar view" refers to viewing an object from vertically above (+z side) downward (-z direction).

[0016] 1 is a schematic perspective view of a flow channel device 1 according to this embodiment. The flow channel device 1 includes a flow channel forming section 10, a detection section 20, and a diffusion layer 30. The flow channel forming section 10 and the detection section 20 sandwich the diffusion layer 30.

[0017] As will be described in detail later, in the flow channel device 1, a flow channel 10x is formed in the flow channel forming section 10 using a hydrogel as a forming material. Note that, although the flow channel device 1 is shown in the drawings as having one flow channel 10x, this is not limiting. The flow channel device 1 may also have a configuration having a plurality of flow channels 10x.

[0018] In the flow channel device 1, a solution containing an analyte is caused to flow through the flow channel 10x, causing the analyte to diffuse from inside the flow channel to the diffusion layer 30 outside the flow channel via the hydrogel sidewall. The diffusing analyte can be detected by the detection unit 20. The analyte corresponds to the "chemical substance" in the present invention. Each component will be described below in order.

[0019] [Flow Channel Forming Section] The flow channel forming section 10 has a substrate 11 and a gel layer 15 .

[0020] (Substrate) The substrate 11 supports the gel layer 15. The modulus of rigidity of the substrate 11 is different from the modulus of rigidity of the gel layer 15. For example, the modulus of rigidity of the substrate 11 is higher than the modulus of rigidity of the gel layer 15.

[0021] As long as the effects of the invention are not impaired, various materials, whether organic or inorganic, can be selected as the material for forming the substrate 11. The substrate 11 may or may not be optically transparent.

[0022] Examples of organic materials that form the substrate 11 include polymeric materials and elastomers. Examples of polymeric materials include thermoplastic resins such as polyvinyl chloride, polystyrene, ABS resin, and polylactic acid, and thermosetting resins such as polyimide and phenolic resin. Examples of elastomers include polysilicone and synthetic rubber.

[0023] The substrate 11 may be subjected to various processes by known microfabrication techniques on at least one of the surface and the interior thereof. For example, the substrate 11 may have irregularities or grooves on the surface.

[0024] The base material 11 also has a first through hole 111 and a second through hole 112 that penetrate the base material 11 in the thickness direction (z-axis direction).

[0025] 1, the first through holes 111 are arranged at equal intervals in the y direction on the +x side of the substrate 11. The second through holes 112 are arranged at equal intervals in the y direction on the −x side of the substrate 11.

[0026] (Gel Layer) The gel layer 15 is made of a hydrogel and is provided on one surface 11a of the substrate 11. Hereinafter, the hydrogel that forms the gel layer 15 will be referred to as a "first hydrogel."

[0027] The gel layer 15 is provided so as to overlap a pair of a first through-hole 111 and a second through-hole 112 aligned in the x-axis direction, and one surface 11a of the substrate 11 is exposed around the gel layer 15. In the flow path forming portion 10, the gel layer 15 has a band shape extending in the x-axis direction.

[0028] Examples of polymeric materials constituting the first hydrogel include water-soluble polymers such as polyacrylamide and polyvinyl alcohol, polysaccharides such as chitosan and alginic acid, and proteins such as collagen and albumin. These materials have a three-dimensional network structure and swell by absorbing a solvent to fill most of their volume. A typical solvent that swells the polymeric material constituting the first hydrogel is water.

[0029] Furthermore, a hydrogel that responds to multiple stimuli may be formed by mixing a plurality of these polymer materials as the material for forming the gel layer 15. Furthermore, tough hydrogels such as double network gel, slide-ring gel, Tetra-PEG gel, and nanoclay gel may also be used as the material for forming the gel layer 15.

[0030] The polymer material constituting the first hydrogel can be synthesized by any of various known methods. For example, when the polymer material constituting the first hydrogel is an acrylic polymer material, a three-dimensional network structure can be formed by crosslinking acrylic groups during polymerization of acrylic monomers.

[0031] The type of polymerization reaction when polymerizing the acrylic monomer is not particularly limited, but an example thereof is radical polymerization using a water-soluble photopolymerization initiator. Examples of the water-soluble photoinitiator include 2-oxoglutaric acid, 4'-(2-hydroxyethoxy)-2-hydroxy-2-methylpropiophenone (trade name: Irgacure 2959), lithium phenyl(2,4,6-trimethylbenzoyl)phosphinate (abbreviation: LAP), and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (trade name: VA-086).

[0032] During radical polymerization, a deoxidizer may be added to the reaction system to prevent polymerization inhibition by oxygen. Examples of the deoxidizer include a combination of glucose and glucose oxidase. Radical polymerization may also be carried out under an inert gas atmosphere such as nitrogen or argon.

[0033] When the polymeric material constituting the first hydrogel is a polysaccharide or a protein, the three-dimensional network structure may be formed by physical bonding of the polysaccharide or protein, or by crosslinking the polysaccharide or protein using a crosslinking agent, such as glutaraldehyde.

[0034] Gel layer 15 is obtained by swelling a layer formed from the first hydrogel with a solvent (e.g., water). In the following description, the "gel layer before swelling" may be referred to as "gel layer 12" to distinguish it from gel layer 15, which is the "gel layer after swelling."

[0035] The shape of the gel layer 12 is not particularly limited, and various shapes can be selected depending on the usage form. For example, the gel layer 12 may be in the form of a film, a plate, a block, etc. Among these, the shape of the gel layer 12 is preferably in the form of a film.

[0036] The thickness of the gel layer 12 is not particularly limited, but is preferably a thickness that provides sufficient structural strength to prevent the gel layer 12 from collapsing under its own weight. For example, when a hydrogel containing polyacrylamide is used as the material for forming the gel layer 12, the thickness of the gel layer 12 is preferably 50 μm to 1000 μm, and more preferably 120 μm to 200 μm.

[0037] The strength of the gel layer 12 can be improved by increasing the crosslinking of the polymer material that constitutes the first hydrogel by chemical crosslinking or physical crosslinking, or by increasing the concentration of the polymer material that constitutes the first hydrogel.

[0038] For example, when preparing a hydrogel containing polyacrylamide by polymerizing acrylamide monomers (precursors), the monomer concentration is preferably 0.8 mol / L to 8 mol / L, more preferably 2 mol / L to 4 mol / L.

[0039] Furthermore, when methylenebisacrylamide is used as a chemical crosslinking agent when polymerizing acrylamide monomers, the concentration of the crosslinking agent is preferably 0.01 mol % to 2.0 mol % relative to the monomer, and more preferably 0.03 mol % to 1 mol %.

[0040] The first hydrogel can contain various additives. The type of additive is not particularly limited as long as it does not inhibit hydrogel formation. Examples of additives include biomolecules that improve biocompatibility, silver nanoparticles or surfactants that exhibit antibacterial properties, ionic liquids or conductive polymers that increase conductivity, and magnetic nanoparticles that react to magnetic fields. Adding these additives to the first hydrogel can impart any desired function to the first hydrogel.

[0041] (Interface Structure) Fig. 2 is a cross-sectional view of the flow channel device 1 taken along line II-II in Fig. 1. Fig. 3 is a cross-sectional view of the flow channel device 1 taken along line III-III in Fig. 1.

[0042] As shown in Figures 2 and 3, the flow path forming portion 10 of the flow path device 1 has an adhesive region 10a at the interface between the substrate 11 and the gel layer 15, where the substrate 11 and the gel layer 15 are adhered, and a non-adhesive region 10b where the substrate 11 and the gel layer 15 are not adhered.

[0043] The non-adhesive region 10b is formed in a band shape extending in the x-axis direction and is surrounded by the adhesive region 10a in a closed ring shape in plan view. The shape of the non-adhesive region 10b is an example, and various shapes can be used depending on the design.

[0044] A layer 121 of a silane coupling agent having adhesive functional groups is formed in the adhesive region 10a. The "adhesive functional groups" refer to functional groups that can polymerize with the monomers (precursors) of the polymer material that constitutes the first hydrogel. In the adhesive region 10a, the gel layer 15 is bonded to the adhesive functional groups of the layer 121.

[0045] For example, when an acrylic monomer is used as the monomer, the adhesive functional group can be a (meth)acrylic group, and in this case, the silane coupling agent can be, for example, 3-(methacryloyloxy)propyltrimethoxysilane.

[0046] The first through-hole 111 and the second through-hole 112 each open to the non-adhesive region 10b.

[0047] 2 and 3 , the gel layer 15 is not fixed to the substrate 11 in the non-adhesive region 10b. The gel layer 15 is fixed to the substrate 11 in the adhesive region 10a. Therefore, the portion of the gel layer 15 that overlaps with the non-adhesive region 10b in a planar manner can freely increase in volume in the extension direction of the non-adhesive region 10b and in a direction away from the substrate 11 when the volume increases due to swelling of the first hydrogel. On the other hand, the portion of the gel layer 15 that overlaps with the non-adhesive region 10b in a planar manner is restricted from increasing in volume in a direction intersecting the extension direction of the non-adhesive region 10b.

[0048] As a result, the portion of the gel layer 15 that overlaps the non-bonded region 10b in plan view swells and deforms significantly in the direction away from the substrate 11 to mitigate the increase in internal pressure caused by the volume increase. As a result, a flow path 10x surrounded by the gel layer 15 and the substrate 11 is formed in the flow path forming section 10. The flow path 10x communicates with the first through-hole 111 and the second through-hole 112.

[0049] The shape of the flow channel 10x can be controlled by controlling the pattern shapes of the adhesive region 10a and the non-adhesive region 10b.

[0050] The shape of the flow channel 10x can be controlled by adjusting the type of gel layer 15, the modulus of rigidity of the gel layer 15, the thickness of the gel layer 15, etc. The modulus of rigidity and the swelling rate of the gel layer 15 can be controlled by changing the type of monomer of the polymer material constituting the gel layer 15, the type and amount of the cross-linking agent used, etc.

[0051] The change in shape described above occurs due to the difference in the swelling rate of the gel layer 12 before swelling and the swelling rate of the gel layer 15 after swelling. The change between the gel layer 12 and the gel layer 15 is reversible. Therefore, in the flow channel device 1, the shape of the flow channel 10x can be controlled by controlling the swelling rate of the gel layer. The swelling rate of the gel layer can be controlled by bringing the gel layer into contact with water to cause swelling, drying the gel layer, or the like.

[0052] [Detection Unit] The detection unit 20 has a facing substrate 21 and a sensor 25 .

[0053] (Opposite Substrate) The opposite substrate 21 is provided opposite the flow path forming portion 10 and supports the sensor 25. The opposite substrate 21 has the same shape as the substrate 11 in a plan view, and the outline of the opposite substrate 21 overlaps with the outline of the substrate 11 in a plan view. In Fig. 1, the opposite substrate 21 is shown as a rectangular member in a plan view.

[0054] The opposing substrate 21 has optical transparency and can be manufactured using the same material as the aforementioned substrate 11. The opposing substrate 21 has optical transparency at least to incident light irradiated in the measurement method described below.

[0055] (Sensor) The sensor 25 is provided on the surface 21 a of the opposing substrate 21 on the flow path forming portion 10 side, and is disposed at the interface between the opposing substrate 21 and the diffusion layer 30 .

[0056] The sensor 25 has a detection film 26 and a probe 27 provided on a surface 26a of the detection film 26. The sensor 25 can be an SPR sensor that operates on the principle of surface plasmon resonance (SPR).

[0057] The detection film 26 is provided on the surface 21 a of the opposing substrate 21. In the sensor 25 of this embodiment, the detection film 26 may be a gold thin film made of gold (Au), a thin film covered with gold nanoparticles, or a graphene film.

[0058] 2, the detection film 26 is uniformly and continuously provided on the surface 21a, but this is not limiting. The detection film 26 may be divided into multiple parts and provided discretely on the surface 21a. In this case, the multiple detection films 26 may be arranged in a matrix in plan view, for example.

[0059] The probe 27 is made of a substance that specifically binds to the analyte described above, and is formed by surface-treating the surface 26a of the detection membrane 26 and modifying the surface 26a with a substance that specifically binds to the analyte.

[0060] Examples of the "substance that specifically binds to an analyte" include an antibody to which the analyte specifically binds, and a nucleic acid molecule (aptamer).

[0061] The sensor 25 is not limited to an SPR sensor. For example, the sensor 25 can be a sensor used to measure fluorescence intensity by configuring the detection film 26 using graphene and configuring the probe 27 using a DNA aptamer modified with a fluorescent dye at its end.

[0062] Furthermore, the sensor 25 may be a sensor that uses an aptamer, or may be a sensor that uses a fluorescent molecule as a probe that emits light upon chemical reaction (binding or decomposition) with the analyte.

[0063] Furthermore, an electrochemical sensor may be used as the sensor 25. Examples of electrochemical sensors include a sensor in which an analyte electrochemically reacts on the surface of an electrode, and a sensor in which a probe that electrochemically reacts with an analyte is carried on the surface of an electrode.

[0064] (Diffusion Layer) The diffusion layer 30 is sandwiched between the flow path forming section 10 and the detection section 20 .

[0065] The material forming the diffusion layer 30 is, for example, a gel formed after the polymer material constituting the hydrogel has swelled. Hereinafter, the hydrogel forming the diffusion layer 30 will be referred to as the "second hydrogel." In other words, the material forming the diffusion layer 30 is formed when a liquid such as water flows into the mesh structure of the polymer material, causing the material to swell. Therefore, the diffusion layer 30 can also be said to be a swollen polymer material.

[0066] The polymer material constituting the diffusion layer 30 has a lower swelling degree than the polymer material constituting the gel layer 15. The swelling degree of the polymer material constituting the diffusion layer 30 is not particularly limited as long as it is lower than the swelling degree of the polymer material constituting the gel layer 15. The swelling degree of the polymer material constituting the diffusion layer 30 in one direction is preferably, for example, about 0.8 to 1.2 times the size before swelling.

[0067] Here, the "degree of swelling" is measured using the polymer material constituting the gel layer 15 (i.e., gel layer 12) before swelling and the polymer material constituting the diffusion layer 30 before swelling. Each polymer material is cut into a disk-shaped sample of an appropriate diameter and left to stand in pure water until the size no longer changes. From the size of the sample before and after standing in pure water, the degree of swelling is calculated using the following formula (1): (degree of swelling) = D / D0 (1) (In formula (1), D is the diameter of the largest part of the sample after standing in pure water, and D0 is the diameter of the sample before standing in pure water.)

[0068] The polymer material constituting the diffusion layer 30 is a hydrogel. The polymer material constituting the diffusion layer 30 may be the same as or different from the polymer material constituting the gel layer 15.

[0069] The polymer material constituting the diffusion layer 30 may be, for example, a chemically crosslinked gel that is crosslinked by covalent bonds due to a radical polymerization reaction of a monomer. Examples of the chemically crosslinked gel include polyacrylamide and its derivatives (polydimethylacrylamide, poly-N-isopropylacrylamide, etc.). In this case, by using methylenebisacrylamide as a crosslinking agent, the crosslink density may be increased and the swelling degree of the polymer material constituting the diffusion layer 30 may be kept within the above numerical range.

[0070] The polymer material constituting the diffusion layer 30 may also be a physically crosslinked gel that combines a polymer having a positive or negative charge with an ion having a multivalent charge of the opposite polarity.

[0071] Examples of physically cross-linked gels include: Physically cross-linked gels that are gelled by combining a solution of sodium alginate, a negatively charged polymer, with a calcium solution such as calcium chloride or calcium sulfate; and water-soluble polyaramid poly(2,2'-disulfo-4,4'-bensidineterephthalamide (PBDT)) with various metal polyvalent cations (Ca ２＋ , Fe ２＋ , Al ３＋ , Zr ４＋ , Ti ４＋ Examples include physically cross-linked gels that combine a polymer with a polymer such as a polymeric polymer.

[0072] Instead of PBDT, TEMPO-oxidized cellulose nanofibers (NIPPON PAPER INDUSTRIES CO., LTD.), which are also negatively charged, or cellulose nanofibers defibrated by a phosphoric acid esterification method (Oji Holdings Corporation) may also be used.

[0073] Here, "TEMPO" is an abbreviation for 2,2,6,6-tetramethylpiperidine-1-oxyl.

[0074] The diffusion layer 30 covers the outer surface 15a of the gel layer 15. Therefore, when an aqueous liquid is poured into the flow path 10x, the aqueous liquid permeates the gel layer 15 and reaches the diffusion layer 30 located outside the flow path 10x.

[0075] When the diffusion layer 30 is made of a hydrogel, the aqueous liquid that reaches the diffusion layer 30 can diffuse into the diffusion layer 30. Therefore, by placing any object (e.g., cells, cultured tissue) inside the diffusion layer 30 in advance, the aqueous liquid can be selectively supplied to the object placed on the diffusion layer 30.

[0076] By changing the polymer material constituting the diffusion layer 30, the diffusion layer 30 can have various functions. For example, when a hydrogel having a positive or negative charge is used as the polymer material constituting the diffusion layer 30, the diffusion layer 30 has a function of preventing the diffusion of small molecules having a specific charge into the flow channel 10x. Such a diffusion layer 30 has a function of blocking small molecules having a specific charge from diffusing from the inside to the outside of the flow channel 10x.

[0077] Furthermore, a hydrogel that switches between hydrophilic and hydrophobic properties in response to an external stimulus can also be used as the polymer material that constitutes the diffusion layer 30. When the hydrogel that constitutes the diffusion layer 30 becomes hydrophilic in response to an external stimulus, the diffusion layer 30 can limit the analytes that diffuse within the diffusion layer 30 to hydrophilic ones. On the other hand, when the hydrogel that constitutes the diffusion layer 30 becomes hydrophobic in response to an external stimulus, the diffusion layer 30 can limit the analytes that diffuse within the diffusion layer 30 to hydrophobic ones.

[0078] Alternatively, a hydrogel that can change its swelling degree in response to an external stimulus can be used as the polymer material constituting the diffusion layer 30. In a diffusion layer 30 in which the swelling degree of the hydrogel is relatively high, the diffusion rate of the analyte diffusing therethrough is relatively slower than in a diffusion layer 30 in which the swelling degree is relatively low.

[0079] There are no particular limitations on the mechanical strength of the diffusion layer 30. For example, if the diffusion layer 30 is required to have an elastic modulus (up to 1.3 MPa) similar to that of polydimethylsiloxane (PDMS), a double-network gel, which is a composite of a physically cross-linked gel and a chemically cross-linked gel, is preferred as the polymer material constituting the diffusion layer 30. The double-network gel has a strong double-network structure, which further improves the mechanical strength.

[0080] There is no particular limitation on the shape of the diffusion layer 30. The thickness of the diffusion layer 30 is greater than the height of the gel layer 15 and can be set to any appropriate thickness.

[0081] The polymer material constituting the diffusion layer 30 may contain various additives as long as the additives do not cause a significant change in the degree of swelling. By using any additive, the diffusion layer 30 can be given any desired function.

[0082] The additives in the diffusion layer 30 are not particularly limited as long as they do not inhibit gel formation. Examples include biomolecules that improve biocompatibility, silver nanoparticles and surfactants that exhibit antibacterial properties, ionic liquids and conductive polymers that increase conductivity, magnetic nanoparticles that react to magnetic fields, and proteins that bind to glucose to enhance fluorescence intensity.

[0083] (Other Configurations) The flow path device 1 may have pipes 51 and 52 connected to the flow path 10x. Specifically, as shown in Fig. 3 , the pipes 51 and 52 can be connected to the flow path 10x by connecting the pipes 51 and 52 to a first through hole 111 and a second through hole 112 of the substrate 11.

[0084] In the flow channel device 1, when connecting piping to the flow channel 10x, it is not necessary to directly connect the piping to the hydrogel flow channel 10x by connecting the piping to the first through-hole 111 and the second through-hole 112 of the base material 11. Therefore, damage to the flow channel 10x (damage to the gel layer 15) can be suppressed.

[0085] 4 and 5 are explanatory diagrams showing a method for detecting an analyte A using the flow channel device 1. Figures 4 and 5 are diagrams corresponding to the field of view of Figure 2.

[0086] The flow path device 1 can simulate the structure of skin or the structure of digestive organs such as the esophagus and intestines, for example, by regarding the flow path 10x as circulatory system tubular tissue such as blood vessels and lymph, and the diffusion layer 30 as interstitial tissue.

[0087] In such a flow channel device 1, by flowing a solution containing an analyte inside the flow channel 10x, the analyte can be diffused into the diffusion layer 30, which is regarded as the interstitial tissue of the biological tissue simulated by the flow channel device 1. At this time, the flow channel device 1 can measure the dynamics (diffusion state) of the analyte diffusing through the diffusion layer 30 by detecting the analyte with the detection unit 20.

[0088] 4, when the analyte solution 100 is pumped into the flow channel 10x, the analyte solution 100 diffuses into the diffusion layer 30 through the gel layer 15. As a result, the analyte A contained in the analyte solution 100 diffuses into the diffusion layer 30.

[0089] As time passes after the start of the delivery of the analyte solution 100, the analyte solution 100 reaches the sensor 25 of the detection unit 20, as shown in Figure 5. At the sensor 25, the probe 27 provided on the surface captures the analyte A. In Figure 5, the analyte A captured by the probe 27 is indicated by the symbol A1. As the probe 27 captures the analyte A, the composition of the diffusion layer 30 near the surface of the detection membrane 26 changes, and the refractive index of the diffusion layer 30 also changes.

[0090] In such a flow channel device 1, p-polarized light (incident light IL) is irradiated onto the detection film 26 at an incident angle θ via the opposing substrate 21, and reflected light RL reflected by the detection film 26 is detected. At this time, the intensity of the detected reflected light RL changes depending on the incident angle, and exhibits a minimum value at an incident angle θ larger than the critical angle of the incident light IL.

[0091] The angle at which the minimum value is obtained (plasmon resonance angle) varies depending on the refractive index near the surface of the detection film 26. The relationship between the amount of analyte A adsorbed and the resonance angle shift can be determined by simulation using a known method.

[0092] Therefore, in the flow channel device 1, various information such as the adsorption range of the analyte A and the diffusion time of the analyte solution 100 can be measured by detecting the change in intensity of the reflected light RL.

[0093] Furthermore, even if a sensor configuration other than an SPR sensor is adopted as the sensor 25, the above-mentioned various pieces of information can be measured based on the detection results of the sensor.

[0094] The flow path device 1 configured as described above makes it possible to create a tissue-like structure that simulates the biological environment on a chip outside of a living organism, and provides a device that can measure molecular diffusion from inside the structure to outside the structure via a blood vessel-like tubular structure.

[0095] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on the design, specifications, etc., without departing from the spirit of the present invention.

[0096] DESCRIPTION OF SYMBOLS 1...flow path device, 10...flow path forming portion, 10a...adhesion region, 10b...non-adhesion region, 10x...flow path, 11...substrate, 12, 15...gel layer, 20...detection portion, 21...opposite substrate, 21a...surface, 25...sensor, 26...detection membrane, 26a...surface, 27...probe, 30...diffusion layer, 51, 52...piping, 111...first through-hole, 112...second through-hole, A...analyte

Claims

1. A flow channel device capable of detecting chemical substances diffusing from inside the flow channel to outside the flow channel, A channel forming section having the channel formed of the first hydrogel, A detection unit is arranged opposite to the flow path of the flow path forming unit, It comprises a diffusion layer formed of a second hydrogel and sandwiched between the channel forming section and the detection section, The channel forming section comprises a base material and The first hydrogel is formed as the forming material and the gel layer is provided on the upper surface of the substrate, At the interface between the substrate and the gel layer, there is an adhesive region where the substrate and the gel layer are bonded, A non-adherent region is formed in which the substrate and the gel layer do not adhere to each other. In the non-adherent region, the gel layer is separated from the substrate, and the flow channel is formed surrounded by the gel layer and the substrate. The detection unit has a counter substrate and A flow channel device having a sensor provided at the interface between the opposing substrate and the diffusion layer.

2. In the gel layer, the non-adherent region surrounds the adhesive region in a closed annular shape in a plan view. The substrate has a first through hole and a second through hole that penetrate in the thickness direction of the substrate, The flow channel device according to claim 1, wherein the first through hole and the second through hole each open into the non-adhesive region and communicate with the flow channel.

3. The flow channel device according to claim 1 or 2, wherein the substrate is exposed around the gel layer.

4. A flow channel device according to claim 1 or 2, having piping connected to the flow channel.

5. The sensor comprises a detection film provided on the surface of the opposing substrate, A probe provided on the surface of the detection film, which specifically binds to the chemical substance, A flow channel device according to claim 1 or 2, having the following characteristics: