JP2015081843A - Conductive material for biosensor and biosensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive material for a biosensor which makes it possible to achieve higher sensitivity of the biosensor, and a biosensor made using the conductive material.SOLUTION: A conductive material for a biosensor comprises a base material, and a conductive layer formed on the base material and comprising resin and a metal nanowire, the conductive layer having a metal nanowire exposure part with at least part of the metal nanowire exposed on the surface of the conductive layer.

Description

  The present invention relates to a conductive material for a biosensor using a metal nanowire and a biosensor.

Various methods have been developed as a method for qualitatively or quantitatively determining a specific component in a sample using a biological substance.
For example, immunochromatography is a test method that uses an antigen-antibody reaction, and since it can detect a target substance with a simple procedure, it has been put to practical use in influenza virus tests and pregnancy tests. Immunochromatography has great advantages in terms of portability and compatibility with various target substances, but has problems such as poor sensitivity. Further, although the inspection time is relatively short, detection in a shorter time may be required. Specifically, in immunochromatography, when the target substance is at a low concentration, it cannot be detected and the screening test accuracy is low, and it takes about 5 to 30 minutes for the sample to move on the membrane. (Mobile phase) is necessary, and high viscosity samples need to be diluted, which may complicate operations. There is still room for improvement in order to realize early detection and early treatment of infections, etc. .

  In order to solve the above problems, biosensors using electrochemical techniques have been developed and many studies have been conducted. For example, electrode materials and electrode structures have been studied, and recently, highly sensitive biosensors using nanomaterials such as carbon nanotubes have been studied (see, for example, Patent Documents 1 and 2).

JP 2008-64724 A JP 2010-230379 A

  However, the biosensor using the carbon nanotube has a complicated manufacturing process, and the carbon nanotube has a problem that it is difficult to form a thin film or form a pattern. In addition, there is a problem that carbon nanotubes have lower conductivity than metals.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a biosensor conductive material capable of increasing the sensitivity of a biosensor and a biosensor using the same.

  In order to achieve the above object, the present invention has a base material and a conductive layer formed on the base material and containing a resin and metal nanowires, and the conductive layer is at least part of the metal nanowires. It has a metal nanowire exposure part exposed to the surface of the said conductive layer, The conductive material for biosensors characterized by the above-mentioned is provided.

  In the present invention, the conductivity can be improved by containing the metal nanowire in the conductive layer. Therefore, the use of the biosensor conductive material of the present invention enables high-sensitivity and short-time inspection. It is also possible to detect trace components. Moreover, in this invention, since a conductive layer contains metal nanowire and resin, pattern formation and thin film formation are easy.

  In the said invention, it is preferable that the said conductive layer is formed in the pattern form on the said base material. Conductive materials for biosensors corresponding to various forms can be obtained.

  In the present invention, the specific binding substance that specifically binds to the target substance or the target substance may be immobilized on the exposed portion of the metal nanowire. In this case, the specific binding substance is preferably an antibody or an aptamer. In the present invention, a target substance or a specific binding substance can be detected using a specific reaction.

  Moreover, in this invention, the insulating layer may be formed in the pattern form on the said base material in which the said conductive layer was formed. It is possible to prevent the sample from coming into contact with an electrode or a wiring connected to the conductive layer.

  The present invention also provides a biosensor comprising a sensor unit having the above-described biosensor conductive material.

  In the present invention, by having the above-described conductive material for biosensor, high-sensitivity and short-time inspection can be performed, and trace components can be detected.

  In the present invention, there is an effect that it is possible to provide a biosensor that can be inspected with high sensitivity and in a short time, and can detect even a trace amount component.

It is a schematic sectional drawing which shows an example of the electrically conductive material for biosensors of this invention. It is a schematic sectional drawing which shows an example of the conductive layer in the electrically conductive material for biosensors of this invention. It is a schematic sectional drawing which shows the other example of the electrically conductive material for biosensors of this invention. It is a schematic diagram which shows an example of the usage method of the biosensor of this invention. It is a schematic sectional drawing which shows the other example of the electrically conductive material for biosensors of this invention. It is the schematic plan view and sectional drawing which show the other example of the electrically conductive material for biosensors of this invention. It is a schematic plan view which shows the other example of the electrically conductive material for biosensors of this invention. It is a schematic diagram which shows an example of the biosensor of this invention. It is a schematic diagram which shows the other example of the biosensor of this invention.

  Hereinafter, the conductive material for a biosensor and the biosensor of the present invention will be described in detail.

A. Conductive material for biosensor The conductive material for biosensor of the present invention has a base material and a conductive layer formed on the base material and containing a resin and metal nanowires, and the conductive layer is made of the metal nanowires. It has a metal nanowire exposure part at least one part exposed to the surface of the said conductive layer, It is characterized by the above-mentioned.

The biosensor conductive material of the present invention will be described with reference to the drawings.
FIG. 1A is a schematic cross-sectional view showing an example of the biosensor conductive material of the present invention, and FIG. 1B is an enlarged view of a broken line part of FIG. As illustrated in FIG. 1A, the biosensor conductive material 1 is obtained by forming a conductive layer 3 containing a resin and metal nanowires on a base material 2. As illustrated in FIG. 1B, the conductive layer 3 has a metal nanowire exposed portion 5 in which a part of the metal nanowire 4 is exposed on the surface of the conductive layer 3.

  Here, “at least a part of the metal nanowire is exposed on the surface of the conductive layer” means that the metal nanowire is in contact with the surface of the conductive layer. For example, it refers to the case as shown in FIG. On the other hand, when the metal nanowire 4 is coated with the resin contained in the conductive layer 3 even when the metal nanowire 4 exists on the surface of the conductive layer 3 as shown in FIG. Does not correspond to the state of being exposed on the surface of the conductive layer.

FIG. 3A is a schematic sectional view showing another example of the conductive material for a biosensor of the present invention, and FIG. 3B is an enlarged view of a broken line part of FIG. As illustrated in FIGS. 3A and 3B, in the biosensor conductive material 1, the target substance and the metal nanowire exposed portion 5 in which a part of the metal nanowire 4 is exposed on the surface of the conductive layer 3. A specific binding substance 7 that specifically binds is immobilized.
In the example shown in FIG. 3, the specific binding substance is fixed to the exposed portion of the metal nanowire. However, the present invention is not limited to this, and the target substance may be fixed to the exposed portion of the metal nanowire.
In the present invention, when the conductive layer has the exposed portion of the metal nanowire, the specific binding substance or the target substance can be fixed to the metal nanowire.

FIG. 4 is a schematic diagram showing an example of a method for detecting a target substance using the biosensor conductive material of the present invention. The biosensor conductive material shown in FIG. 4 is the same as the biosensor conductive material shown in FIG. As shown in FIG. 4, in the biosensor conductive material 1, when a sample containing the target substance 10 is brought into contact with the conductive layer 3, the specific binding substance 7 immobilized on the exposed portion of the metal nanowire of the conductive layer 3 becomes the target substance. 10 specifically binds. Although not shown, an electrode is connected to the conductive layer 3, and the presence of the target substance 10 that specifically binds to the specific binding substance 7 can be measured as a change in current value.
In the example shown in FIG. 4, the target substance is detected using the biosensor conductive material of the present invention. However, the present invention is not limited to this, and the target substance is fixed to the exposed portion of the metal nanowire. Can detect specific binding substances.

  In this invention, since a conductive layer contains metal nanowire, it is very excellent in electroconductivity. Accordingly, by using the biosensor conductive material of the present invention, it is possible to detect the target substance or specific binding substance with high sensitivity and in a short time. In addition, since the detection sensitivity is high, detection is possible even if the target substance or the specific binding substance is in a very small amount, and the screening test accuracy can be improved. Therefore, for example, early detection and early treatment of infectious diseases and the like can be realized. Furthermore, in the present invention, the sample does not need to move on the membrane, for example, as in immunochromatography, so there is no need to use a developing solution (mobile phase), and there is no need to dilute even if the sample has a high viscosity, Since the sample can be directly supplied to the biosensor, the inspection can be performed with a simple operation.

FIG. 5 is a schematic sectional view showing another example of the conductive material for a biosensor of the present invention. As illustrated in FIG. 5, in the biosensor conductive material 1, the conductive layer 3 is formed in a pattern on the substrate 2.
In the present invention, since the conductive layer contains the metal nanowires and the resin, the conductive layer can be easily formed on the substrate, and the film can be easily thinned. In addition, a fine conductive layer pattern can be easily formed by a known method such as a photolithography method. Therefore, the biosensor can be applied to various fields by using the biosensor conductive material of the present invention. In addition, the size of the biosensor can be reduced.

  Hereinafter, each structure in the electrically conductive material for biosensors of this invention is demonstrated.

1. Conductive layer The conductive layer in the present invention is formed on a substrate and contains a resin and a metal nanowire, and has a metal nanowire exposed portion in which at least a part of the metal nanowire is exposed on the surface of the conductive layer. It is. Hereinafter, each structure in the conductive layer will be described.

(1) Metal nanowire The metal constituting the metal nanowire used in the present invention is not particularly limited as long as it can fix a specific binding substance or target substance. For example, silver, copper, gold, Examples include platinum, palladium, rhodium, iridium, ruthenium, osmium, iron, cobalt, tin and the like. Among these, silver nanowires and copper nanowires are preferably used.

  The average diameter of the metal nanowire is not particularly limited as long as desired conductivity is obtained, and can be, for example, in the range of 0.1 nm to 1000 nm. In the present invention, since the conductive layer does not require transparency, the diameter of the metal nanowire may be large.

The average length of the metal nanowires is not particularly limited as long as it is sufficiently larger than the average diameter of the metal nanowires and desired conductivity is obtained. For example, the average length of the metal nanowires can be in the range of 50 nm to 2000 μm. Especially, since the distribution range of the length at the time of metal nanowire manufacture is wide, it is preferable to exist in the range of 400 nm-2000 micrometers. If the length of the metal nanowire is long, a long conductive path can be formed with one metal nanowire.
Here, the diameter and length of the metal nanowire can be measured using, for example, a transmission electron microscope.

  The method for producing the metal nanowire is not particularly limited as long as it is a known method.

  The content of the metal nanowire in the conductive layer is not particularly limited as long as the conductive layer having the exposed portion of the metal nanowire can be obtained and desired conductivity is obtained. For example, 0.01% by mass to 90% It can be in the range of mass%, and is preferably in the range of 1 mass% to 80 mass%, particularly in the range of 5 mass% to 40 mass%. In addition, since transparency is not required for the conductive layer in the present invention, the content of metal nanowires may be large.

(2) Metal nanowire exposed portion In the present invention, at the metal nanowire exposed portion, at least a part of the metal nanowire is exposed on the surface of the conductive layer.
Here, the fact that at least a part of the metal nanowire is exposed on the surface of the conductive layer is directly confirmed using, for example, a commercially available atomic force microscope (AFM) having a function of observing the conductivity of the layer surface. be able to. For example, using a NanoNavi probe station equipped with Nano-Pico CURRENT / CITS mode manufactured by Seiko Instruments Inc. and a S-image high-resolution small stage unit, a conductive cantilever (for example, SI-DF3-R) and a conductive layer The surface of the conductive layer can be scanned while a bias voltage (for example, 3 V to 5 V) is applied between them, the current flowing between the conductive cantilever and the conductive layer can be detected and the current distribution can be observed and confirmed.

  The extent to which the metal nanowire is exposed in the exposed portion of the metal nanowire may be at least part of the metal nanowire exposed to the extent that the specific binding substance or the target substance can be immobilized. For example, as shown in FIG. 2A, a part of the metal nanowire 4 may be exposed with respect to the diameter of the metal nanowire 4, or although not shown, the metal nanowire 4 may be fully exposed with respect to the diameter of the metal nanowire 4. Good. Specifically, the thickness of the portion where the metal nanowire protrudes from the surface of the conductive layer is preferably 20 nm or less. Here, the thickness of the portion where the metal nanowire protrudes from the surface of the conductive layer refers to the thickness d as shown in FIG.

  In addition, the number of exposed metal nanowires in the conductive layer is preferably 5 or more, and more preferably 20 or more, per conductive layer disposed in the reaction region to which the sample is supplied. For example, in FIG. 7, one conductive layer 3 is disposed in one reaction region 11, and the number of exposed metal nanowires in the conductive layer 3 in the reaction region 11 is preferably in the above range. Further, for example, in FIGS. 6A and 6B, three conductive layers 3a, 3b, and 3c are arranged in one reaction region 11, and in each of the conductive layers 3a, 3b, and 3c in the reaction region 11, The number of exposed metal nanowires is preferably in the above range. Details of FIGS. 6 and 7 will be described later.

  The conductive layer only needs to have the exposed portion of the metal nanowire, and the ratio of the area occupied by the exposed portion of the metal nanowire on the surface of the conductive layer is not particularly limited and can be appropriately adjusted according to the purpose.

(3) Resin The resin used for the conductive layer in the present invention is appropriately selected according to the method for forming the conductive layer.
For example, when a conductive layer is formed by applying an ink containing a resin and metal nanowires on a substrate, the resin is not particularly limited as long as it functions as a binder. Specifically, And curable resins such as thermosetting resins, ultraviolet curable resins, and electron beam curable resins, and thermoplastic resins. More specifically, polypropylene, polyethylene, polyethylene terephthalate, acrylic, polyester, polyurethane, polyvinyl chloride, acrylic urethane resin, polyester acrylate resin, epoxy acrylate resin, polyol acrylate resin, and the like can be given.
In addition, when an ink containing metal nanowires and a solvent that swells the base material is applied on the base material, the base material is swollen and the metal nanowires are embedded in the base material surface, the resin may be a predetermined solvent. For example, curable resins such as thermosetting resins, ultraviolet curable resins, and electron beam curable resins, and thermoplastic resins can be used. Specifically, resins such as those described in US Patent Application Publication No. 2011/0281070 and Japanese Translation of PCT International Publication No. 2012-500086 can be used. More specifically, acrylonitrile butadiene styrene copolymer (ABS resin), polycarbonate, acrylic resin such as polyacrylate and polymethyl methacrylate (PMMA), polystyrene, polyvinyl chloride and the like can be mentioned.

(4) Conductive layer In this invention, it is preferable that the conductive layer is formed in pattern shape on the base material.
For example, when a conductive layer is formed in a pattern on a substrate and a plurality of conductive layers are provided, at least one of the plurality of conductive layers is used for calibration or the number of samples is increased. Alternatively, different specific binding substances or target substances can be fixed to the exposed portions of the metal nanowires of the respective conductive layers. In addition, a multifaceted biosensor conductive material can be obtained.
Specifically, as shown in FIGS. 6A to 6D, conductive layers 3a, 3b, and 3c are formed in a pattern on the substrate 2, and a plurality of conductive layers 3a, 3b, and 3c are formed. In the case where it is provided, a specific binding substance 7 is fixed to the exposed portions 5 of the metal nanowires of the conductive layers 3a and 3b and used for the inspection of the sample, and the exposed portions 5 of the other conductive layers 3c are specific to the exposed portions of the metal nanowires. The binding substance 7 can be used for calibration without fixing. The specific binding substances 7 fixed to the exposed portions 5 of the metal nanowires of the conductive layers 3a and 3b may be the same or different. If they are the same, the number of samples can be increased, and if they are different, a plurality of items can be inspected simultaneously by one inspection. 6B is a sectional view taken along line AA in FIG. 6A, FIG. 6C is a sectional view taken along line BB in FIG. 6A, and FIG. 6D is FIG. FIG.
Moreover, as shown in FIG. 7, the conductive layer 3 can be formed in a pattern shape on the base material 2 to obtain a multi-surface conductive material for a biosensor. In FIG. 7, a part of an insulating layer 6 described later is indicated by a broken line.

  When the conductive layer is formed in a pattern, one or more conductive layers may be disposed in the reaction region to which the sample is supplied. Among these, from the above viewpoint, it is preferable that a plurality of conductive layers are arranged in the reaction region. For example, in FIGS. 6A and 6B, a plurality of conductive layers 3 a, 3 b, and 3 c are arranged in the reaction region 11, and one conductive layer 3 is arranged in the reaction region 11 in FIG. 7.

  If the conductive layer used for calibration is not formed, calibration data prepared in advance may be used.

  When the conductive layer is formed in a pattern, the width of the pattern of the conductive layer is not particularly limited as long as desired conductivity can be obtained and can be formed. It can be set to about μm to several hundred μm. In the present invention, since the conductive layer is not required to be transparent, the density of the metal nanowires in the conductive layer can be increased, and therefore conductivity can be ensured even with a fine pattern.

  The pattern shape of the conductive layer is not particularly limited and can be an arbitrary shape.

The conductivity of the conductive layer is not particularly limited as long as it can be used as a biosensor. For example, the surface resistivity of the conductive layer can be 500Ω / □ or less, among which 100Ω / □ or less, In particular, it is preferably 50Ω / □ or less. This is because when the surface resistivity of the conductive layer is high, measurement cannot be performed with a minute voltage, and water decomposition or corrosion reaction in the sample is accelerated at a high voltage.
Here, the surface resistivity can be measured using, for example, a resistivity meter Loresta manufactured by Mitsubishi Chemical Corporation.

The thickness of the conductive layer is not particularly limited as long as desired conductivity is obtained, and is appropriately selected according to the method for forming the conductive layer.
For example, when a conductive layer is formed by applying an ink containing a resin and metal nanowires on a substrate, the thickness of the conductive layer can be in the range of 10 nm to 1 mm, for example, 0.1 μm to 100 μm. It is preferable that it exists in the range of 0.3 micrometer-50 micrometers especially. If the conductive layer is thin, it is difficult to obtain electrical continuity and manufacturing is difficult. On the other hand, if the conductive layer is thick, the manufacturing cost increases. In the present invention, since the conductive layer does not require transparency, the thickness of the conductive layer may be large.
In addition, when an ink containing metal nanowires and a solvent that swells the substrate is applied on the substrate, the substrate is swollen, and the metal nanowire is embedded on the substrate surface, the metal nanowire is embedded on the substrate surface. The thickness of the portion, that is, the thickness of the conductive layer is preferably greater than the diameter of the metal nanowire. Specifically, the thickness of the conductive layer can be in the range of 1 to 5 times the diameter of the metal nanowire. More specifically, the thickness of the conductive layer can be in the range of 0.1 nm to 5 μm. If the thickness of the portion where the metal nanowire is embedded on the surface of the substrate is within the above range, a contact is easily formed between the metal nanowires, and good conductivity is obtained.

(5) Method for forming conductive layer The method for forming the conductive layer is not particularly limited as long as it is a method capable of forming a conductive layer having an exposed portion of metal nanowires. For example, resin and metal nanowires are formed on a substrate. A method of forming a conductive layer by applying an ink containing a metal, applying an ink containing a metal nanowire and a solvent that swells the substrate on the substrate, swelling the substrate, and forming a metal nanowire on the substrate surface The method of embedding is mentioned. In the case of the former method, a commercially available ink can be used as the ink containing resin and metal nanowires. Further, a commercially available conductive film in which a conductive layer is laminated on a substrate may be used. On the other hand, in the case of the latter method, specifically, the method described in US Patent Application Publication No. 2011/0281070 specification and Japanese translations of PCT publication No. 2012-500086 can be applied.

  The method of forming the conductive layer in a pattern is not particularly limited. For example, a method of applying an ink containing a resin and metal nanowires on a substrate in a pattern, or forming a resist pattern on the conductive layer And a method of etching, a method of transferring the conductive layer onto the substrate, a method of partially peeling off the conductive layer formed on the substrate, and the like.

  Moreover, in order to improve the electroconductivity of a conductive layer, you may perform baking and pressurization.

2. Base material The base material in this invention supports the said conductive layer.
The substrate is not particularly limited as long as the conductive layer can be formed on the substrate. Moreover, the base material may or may not have transparency. For example, a glass substrate, a resin substrate, or the like can be used, and among them, a resin substrate is preferably used from the viewpoint of lightness and flexibility.
Examples of the resin substrate include polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, and modified polyester, polyolefins such as polystyrene and cyclic olefin resins, and vinyl resins such as polyvinyl chloride and polyvinylidene chloride. , Polyether ether ketone, polysulfone, polyether sulfone, polycarbonate, polyamide, polyimide, acrylic, triacetyl cellulose and the like.
In addition, the resin base material can be subjected to a surface treatment or an easy-adhesion layer in order to ensure ink wettability and adhesiveness. A general thing can be applied about a surface treatment or an easily bonding layer.
The thickness of the substrate is not particularly limited as long as the conductive layer can be formed on the substrate, and is appropriately selected depending on the application.

3. Specific binding substance and target substance In the present invention, a specific binding substance or target substance that specifically binds to the target substance may be immobilized on the exposed portion of the metal nanowire. In the biosensor using the biosensor conductive material of the present invention, the specific binding substance or the target substance is fixed to the exposed portion of the metal nanowire.

  The specific binding substance is not particularly limited as long as it specifically binds to the target substance, and examples thereof include antibodies and aptamers.

  Examples of the target substance include antigens and substances that specifically bind to aptamers. Specifically, natural antigens such as viruses, bacteria, cells, proteins, peptides, saccharides, nucleic acids (DNA, RNA), lipids, coenzymes, and complexes thereof, derivatives of natural antigens, and artificially synthesized Haptens, artificial antigens and the like.

  As a method for immobilizing a specific binding substance or target substance on the exposed portion of the metal nanowire, a general method can be used as a method for immobilizing an antibody, aptamer, antigen or the like on the metal surface. For example, a method of immobilizing a specific binding substance or target substance on the surface of the exposed portion of the metal nanowire via a linker can be exemplified.

4). Insulating layer In the present invention, as illustrated in FIGS. 6A to 6C and FIG. 7, the insulating layer 6 is formed in a pattern on the substrate 2 on which the conductive layer 3a, 3b, 3c or 3 is formed. It may be formed. The insulating layer is provided to define a reaction region to which the sample is supplied, to retain the sample on the conductive layer, and to prevent the sample from coming into contact with an electrode, wiring, or the like.

  The insulating material used for the insulating layer is not particularly limited as long as it can form a patterned insulating layer on the base material on which the conductive layer is formed. Either an organic material or an inorganic material can be used. Can also be used. Examples of the organic material include a photosensitive resin. Examples of the inorganic material include silicon oxide, silicon nitride, and silicon oxynitride.

  As the formation position of the insulating layer, as illustrated in FIGS. 6A to 6C and FIG. 7, the insulating layer is formed so as to surround the reaction region 11 to which the sample is supplied, and the conductive layer 3a, 3b, 3c, or 3 It suffices if the insulating layer 6 is formed so that the connecting portions 12a and 12b connected to the electrodes, wirings, and the like are exposed.

  The thickness of the insulating layer is not particularly limited as long as the sample does not overflow, and is appropriately adjusted.

  The method for forming the insulating layer is not particularly limited as long as the insulating layer can be formed in a pattern on the substrate on which the conductive layer is formed. For example, a photolithography method, a printing method, or the like can be used. Can be mentioned.

5. Conductive material for biosensor The form of the conductive material for biosensor of the present invention is not particularly limited, and is appropriately selected according to the inspection purpose, inspection object, inspection method, and the like. For example, film shape, plate shape, rod shape Etc.

B. Biosensor The biosensor of the present invention includes a sensor unit having the above-described conductive material for biosensor.

The biosensor of the present invention can be tested with high sensitivity and in a short time by having the above-described biosensor conductive material. Further, it is possible to detect a trace component, and the screening inspection accuracy can be improved.
Hereinafter, each configuration in the biosensor of the present invention will be described.

1. Sensor part The sensor part in this invention has the above-mentioned electrically-conductive material for biosensors.
In the biosensor of the present invention, the biosensor conductive material has a base material and a conductive layer formed on the base material and containing a resin and a metal nanowire, and the conductive layer is the metal nanowire. At least a portion of the metal nanowire exposed on the surface of the conductive layer, the specific binding substance that specifically binds to the target substance or the target substance is immobilized on the exposed part of the metal nanowire It is what.
The biosensor conductive material has been described in detail in the section “A. Conductive Material for Biosensor” above, and thus the description thereof is omitted here.

2. Electrode and Wiring In the present invention, an electrode and wiring are usually connected to the conductive layer of the biosensor conductive material.
The electrodes and wirings are appropriately selected according to the use and structure of the biosensor of the present invention. For example, examples of the electrode include a working electrode, a counter electrode, and a reference electrode. In a biosensor using a field effect transistor, a source electrode and a drain electrode are connected to a conductive layer. Specifically, in FIGS. 6A to 6C and FIG. 7, among the connection portions 12a and 12b at both ends of the conductive layers 3a, 3b, and 3c, one connection portion 12a has a source electrode and the other connection. A drain electrode is connected to the portion 12b.

3. Biosensor The form of the biosensor of the present invention is not particularly limited, and is appropriately selected according to the inspection purpose, inspection object, inspection method, and the like. For example, a film shape, a plate shape, a rod shape, a cylindrical shape, a spherical shape, etc. Can be mentioned.

  Specifically, a flat plate biosensor as shown in FIGS. 6A to 6C and FIG.

Further, a cotton swab-type biosensor 20 as shown in FIG. The swab-type biosensor 20 includes a support body 21, a sensor unit 15 disposed at the tip of the support body 21, and a covering unit 22 disposed so as to cover the sensor unit 15.
For example, when the nasal cavity or the oral cavity is wiped with a cotton swab-type biosensor 20 and nasal discharge, mucous membrane, saliva, etc. are attached as a sample, the sample passes through the cover 22 and is introduced into the sensor unit 15 for inspection. Provided. As described above, in a swab-type biosensor, a sample can be collected easily and quickly, and a target substance contained in the sample can be inspected.

In the swab-type biosensor, a material used for a conventional swab such as plastic or a metal material can be used as the support. In the case of a metal material, the support can function as an electrode. In this case, the surface of the support made of a metal material may be coated with an insulating material. The shape of the support is not particularly limited, but is generally rod-shaped.
The covering portion is not particularly limited as long as it allows a sample to pass therethrough. For example, the covering portion preferably has hydrophilicity or permeability to allow liquid to pass through. Moreover, it is preferable that the material of a coating | coated part is a thing which does not damage skin and mucous membrane. Specific examples include filter paper, resin membranes used in chromatography, resin meshes, and the like.
In the swab type biosensor, the sensor part is preferably exchangeable. In this case, for example, the tip portion provided with the sensor portion may be detachable, and the swab-type biosensor may be disposable.

Further, a toothbrush type biosensor 30 as shown in FIG. 9 can be exemplified. The toothbrush type biosensor 30 includes a support 31, a plurality of hair bundles 32 provided at the tip of the support 31, and a sample provided at the tip of the support 31 and disposed on the opposite side of the hair bundle 32. A sampling hole 33 and a sensor unit 15 connected to the sample sampling hole 33 are provided.
When the tooth in the oral cavity is brushed with the toothbrush type biosensor 30, saliva, brushed plaque, etc. are injected into the sample collection hole 33 as a sample. Then, the sample is introduced into the sensor unit 15 connected to the sample collection hole 33 and used for inspection. Thus, in a toothbrush type biosensor, a sample can be collected easily and quickly, and a target substance contained in the sample can be inspected.
In this case, any antibody can be used as the specific binding substance in the sensor unit depending on the purpose of the test. For example, a monoclonal antibody against streptococcus (S. mutans, S. sobrinus, S. critus, S. rattus, etc.) that is a causative agent of caries can be used.

In the toothbrush type biosensor, a material used for a conventional toothbrush such as a resin can be used as the support. The shape of the support may be a general toothbrush shape.
A plurality of hair bundles are arranged at the tip of the support. As the hair bundle, a material that is usually used as a hair bundle of a toothbrush such as an artificial material such as resin or a natural material such as pig hair can be used.
A sampling hole is provided in the vicinity of the hair bundle provided at the tip of the support. The position of the sample collection hole is not particularly limited as long as it is the tip of the support, in the vicinity of the hair bundle, and can collect saliva etc. in the oral cavity when a toothbrush type biosensor is inserted into the oral cavity. It is not something.
In the toothbrush type biosensor, the sensor unit is preferably exchangeable. In this case, for example, the sensor part may be detachable, the tip part provided with the sensor part may be detachable, or the toothbrush type biosensor may be disposable.

4). Inspection Method The biosensor of the present invention can be used by connecting to a measuring device. The measuring device connects a biosensor and measures an electrical signal generated by the biosensor. As the measuring device, a general measuring device can be used. For example, the measurement apparatus includes a connection electrode for receiving an electrical signal generated by a biosensor, a calculation unit, a power source, a display unit, and an operation unit. When the biosensor is mounted on the mounting portion of the measurement device, the electrode of the biosensor or the end of the wiring is connected to the connection electrode of the measurement device. By this connection, the electrical signal generated by the biosensor is transmitted to the measuring device.
As an inspection method, for example, a measurer attaches a biosensor to a measurement apparatus, introduces a sample into the sensor unit of the biosensor, and operates the operation unit to start measurement. When the target substance is contained in the sample, the target substance reacts with the specific binding substance of the sensor unit, and an electric signal is detected by the electrode of the biosensor and transmitted to the measuring device. The measuring device converts the electrical signal received from the biosensor into a measured value by the calculation unit. The obtained measurement value is displayed on the display unit, and the measurer can visually recognize the measurement result.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

  Hereinafter, the present invention will be specifically described with reference to examples.

[Example 1]
(Production of biosensor)
First, a cover film of a transferable thin film transparent conductive film (Transparent Conductive Transfer Film; TCTF) manufactured by Hitachi Chemical was peeled off to a PET substrate having a thickness of 200 μm and thermally transferred at 115 ° C. Next, from the TCTF support, exposure is performed with a pattern formed of silver nanowires including an electrode pattern arranged in the reaction region, a wiring pattern drawn from the electrode pattern, and a terminal connector pattern, and the TCTF support Was peeled off to expose TCTF silver nanowires. Thereafter, the unexposed portion was removed by washing with sodium carbonate. Thus, the conductive film in which the conductive layer containing silver nanowires was formed in a pattern was obtained.

  Next, an insulating resist is coated on the conductive film so that the pattern arranged in the reaction region and the pattern connected to the source electrode and the drain electrode are exposed in the fine patterned conductive layer. The layer was formed in a pattern and provided with an insulating and water resistant coating.

  Next, a solution prepared by adding 0.2% (W / W) dithiol to Tris buffer pH 7.2 of 0.1% (W / W) streptavidin manufactured by Roche was prepared immediately before use. Under a microscope, this solution was dropped on the conductive layer located in the reaction region, and was naturally dried at room temperature, and streptavidin was fixed to the silver nanowire by a thiol bond. This produced a biosensor.

(Evaluation)
A conductive wire was fixed with a silver paste to a pattern connected to the source electrode and the drain electrode of the conductive layer, and connected to a potentiostat. Thereafter, physiological saline for control and 0.05% (W / W) biotin from Roche were added to different reaction regions, and cyclic voltammograms of 0.5 V to -0.2 V were applied. . Biotin was detected in the reaction region where streptavidin was immobilized.

[Example 2]
(Production of biosensor)
As described below, a biosensor was produced in the same manner as in Example 1 except that the aptamer was fixed to the silver nanowire instead of streptavidin.
That is, a solution obtained by adding 0.2% (W / W) dithiol to Tris buffer solution of Immuno-Aptamer ^™ , Mouse IgG 0.05% (W / W) manufactured by Nippon Gene was prepared immediately. Under a microscope, this solution was dropped on the conductive layer located in the reaction region, and was naturally dried at room temperature, and the aptamer was fixed to the silver nanowire by a thiol bond.

(Evaluation)
A conductive wire was fixed with a silver paste to a pattern connected to the source electrode and the drain electrode of the conductive layer, and connected to a potentiostat. Thereafter, a control saline solution and Mouse IgG 0.05% (W / W) diet prepared by Roche are added to different reaction regions, and a cyclic voltammogram of 0.5 V to -0.2 V is applied. did. IgG binding was detected in the reaction region where the aptamer was immobilized.

[Example 3]
(Production of biosensor)
A biosensor was produced in the same manner as in Example 1 except that a conductive film was formed as described below.
That is, first, a conductive layer was formed by coating a coating material “Clear Ohm” manufactured by Cambrios Co., Ltd. on a PET film. Next, a photoresist was coated on the conductive layer, and pattern exposure and washing were performed. Thereafter, full etching was performed using “silver nanowire etching solution Pure Etch GNW300” manufactured by Hayashi Junyaku Kogyo Co., Ltd., and the photoresist was peeled off to form a conductive film having a conductive layer formed in a pattern.

(Evaluation)
When evaluated in the same manner as in Example 1, similar results were obtained.

[Example 4]
(Production of biosensor)
A biosensor was produced in the same manner as in Example 2 except that a conductive film was formed in the same manner as in Example 3.

(Evaluation)
When evaluated in the same manner as in Example 2, similar results were obtained.

DESCRIPTION OF SYMBOLS 1 ... Conductive material for biosensors 2 ... Base material 3, 3a, 3b, 3c ... Conductive layer 4 ... Metal nanowire 5 ... Metal nanowire exposed part 6 ... Insulating layer 7 ... Specific binding substance 10 ... Target substance 11 ... Reaction region 15 … Sensor unit 20, 30… Biosensor

Claims (6)

A substrate;
A conductive layer containing a resin and metal nanowires formed on the substrate, wherein the conductive layer includes a metal nanowire exposed portion in which at least a part of the metal nanowire is exposed on a surface of the conductive layer. A conductive material for a biosensor, comprising:   The conductive material for a biosensor according to claim 1, wherein the conductive layer is formed in a pattern on the base material.   The conductive material for a biosensor according to claim 1 or 2, wherein a specific binding substance that specifically binds to a target substance or the target substance is fixed to the exposed portion of the metal nanowire.   4. The biosensor conductive material according to claim 3, wherein the specific binding substance is an antibody or an aptamer.   The conductive material for a biosensor according to any one of claims 1 to 4, wherein an insulating layer is formed in a pattern on the substrate on which the conductive layer is formed.   A biosensor comprising a sensor unit having the biosensor conductive material according to any one of claims 1 to 5.

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