JP2018096875A - Biosensor, method for manufacturing the same, and bio-sensing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable biosensor enabling continuous analysis, and a method for manufacturing the biosensor and a bio-sensing device.SOLUTION: A biosensor includes: at least two electrodes; and a supporting body supporting the at least two electrodes. Each of one or more of the electrodes include: a base body having a metal surface; and a protective layer covering at least a part of the surface, the protective layer being a continuous film made of carbon and having a thickness of 1 μm or larger. The biosensor is cylindrical and enables a continuous analysis by continuously introducing sample liquid into an inside or an outside of a cylinder.SELECTED DRAWING: Figure 3B

Description

  The present invention relates to biological sensing technology.

  At present, medical care is highly developed, and it is possible to grasp the condition by analyzing body fluids such as blood, saliva and urine of patients. For example, research has been conducted on determining the presence or absence of dental caries by measuring the pH of saliva and diagnosing diabetes by measuring the blood sugar level of tears. These examinations are performed, for example, when a patient collects body fluid by himself, and this is measured and analyzed by a medical institution.

  On the other hand, an apparatus for measuring and analyzing body fluid by itself without a patient going to a medical institution has been developed. This not only enables rapid examination and analysis, but can also be used as a means for reducing medical costs in an aging society, as will be described below.

  In general, after self-recognizing poor physical condition, a medical institution is consulted. However, at that stage, it may have end-stage symptoms. In this case, advanced medical care and expensive drug administration are performed, and as a result, the medical cost burden increases.

  If poor physical condition can be detected at an early stage, there is a possibility that it can be cured with mild treatment that does not require medication, such as by reviewing lifestyle habits. For this reason, an increasing number of institutions conduct regular medical examinations as preventive treatments organized by the Health Insurance Association.

  However, since regular screening is generally about once to twice a year, there is a blank period between screenings, and diseases that develop during this period cannot be recognized. Thus, current preventive medicine has its limitations.

  Examination can be performed at a high frequency by using a device that allows the body fluid measurement and analysis to be performed on its own without going to a medical institution. Therefore, it becomes possible to detect changes in physical condition before being aware of it. Therefore, opportunities for advanced medical care and administration of expensive drugs are reduced, and medical costs can be reduced.

  As a method for obtaining information on body fluids, a biological sensor is inserted into the body or attached to the skin or mucous membrane, and information on the body environment is obtained in vivo (in vivo). There is a method of acquiring information ex vivo (in vitro) using a biological sensor placed away from the living body. These have advantages and disadvantages because the patient himself performs the measurement and analysis. For example, in vivo, information on a living body can be acquired without a time difference. However, since the sensor is brought into direct contact with the living body, the influence on the living body is large, and high reliability is required as a device. Since ex vivo does not contact the living body, the influence on the living body is small. However, some body fluids are difficult to obtain, and there is a concern that the obtained body fluid may change over time. It is required to select an appropriate method depending on the application and purpose.

  There are various biosensing techniques, but electrochemical techniques are widely used because, for example, the measurement of blood sugar levels can detect trace components with high sensitivity. In the electrochemical technique, biological information that is a chemical characteristic can be detected as an electrical signal, and thus there is an advantage that it is easy to process and analyze a signal obtained using a semiconductor device or the like. For this reason, development of new electrochemical sensing devices and sensing methods using the same has been actively carried out worldwide.

  For example, Patent Documents 1 to 5 describe technologies related to an ex vivo electrochemical sensing device.

  Patent Document 1 includes a sample chamber having a capacity of 1 μL or less including a working electrode, a counter / reference electrode, a redox mediator, and an analyte reaction enzyme, and the working electrode is separated from the counter / reference electrode by a distance of 200 μm or less. Describes a method for measuring the concentration of an analyte in a body fluid using an in vitro analyte sensor (similar to ex vivo).

  Patent Document 2 describes a technique for simplifying the manufacturing process of a sensor cartridge for measuring urine sugar in which the urine sugar sensor is incorporated in the cartridge body, and reducing the manufacturing cost.

  Patent Document 3 describes a technique for measuring physical condition by measuring the redox potential of saliva.

  In Patent Document 4, the phosphoric acid concentration and calcium concentration in blood separated from a living body are measured by one measurement using a measurement system, the measurement result is displayed visually, and based on the displayed measurement result. And a kidney function control state measuring method for determining a control state of kidney function in a living body.

  In Patent Document 5, the flow path of the ion sensor and the flow path of the reference electrode are separated, the liquid to be measured is allowed to flow only through the flow path of the ion sensor, and A disposable ion sensor unit is described in which a liquid is passed and the flow path of the ion sensor and reference electrode is connected downstream of the ion sensor and reference electrode to form a liquid-liquid contact.

  In these techniques, body fluids such as blood, urine, or saliva are collected, and the blood glucose, urine sugar, oxidant / reductant activity ratio, or ion (chlorine) concentration therein is electrochemically measured. In electrochemical sensing, the stability of the electrode material with respect to the reaction is important because the electrode is brought into contact with a body fluid as a specimen.

  As such a material, carbon is used in addition to a noble metal. This is because carbon is an electrochemically inactive material.

  For example, Patent Document 6 describes using carbon as an electrode material for an electrochemical sensor. The carbon electrode described here was provided so as to cover the insulating substrate, the conductive layer provided on the insulating substrate, the first carbon layer provided on the conductive layer, and the first carbon layer. A second carbon layer. The first carbon layer includes carbon having an SP2 bond and an SP3 bond and having an amorphous structure. The second carbon layer contains carbon having an SP2 bond. Specifically, the first carbon layer is a carbon layer made of diamond-like carbon or amorphous carbon having an amorphous structure, formed by vapor phase growth.

  Patent Document 7 describes an electrochemical sensor for measuring the level of an analyte such as glucose, lactate or oxygen in vivo and / or in vitro.

  Patent Document 8 describes a sensor suitable for implantation in both solid tissue and gel-like tissue for in vivo detection and measurement. This sensor is capable of long-term monitoring of almost continuous or semi-continuous glucose levels by wireless telemetry. This sensor has a) a hermetically sealed housing, b) a detector array, c) a power source such as a battery, and d) a function for accurately processing the detector signal, and operates on the detector array. And a telemetry transmission portal comprising means for stably transmitting the processed detector signal to the outside of the sensor for relaying it to an extracorporeal receiver. .

JP 2012-101092 A JP 11-271259 A JP 2002-207037 A JP 2007-3256 A JP-A-6-148124 International Publication No. 2010/004690 International Publication No. 1999/045387 International Publication No. 2013/016573

  The problems found by the inventor of the prior art when inventing the present invention are described below.

  As shown in Patent Documents 1 to 8, a biosensor has been invented that obtains a numerical value as a biomarker by electrochemically measuring and analyzing a component of a body fluid obtained from a living body. The biosensors described in Patent Documents 1 to 5 adopt an ex vivo method, and are adapted in form and method according to the target measurement system. The biosensor described in Patent Document 6 uses carbon as an electrode material for electrochemical measurement. The biosensors described in Patent Documents 7 and 8 include a control / processing device and components that transmit signals.

  For such an existing biosensor, it is necessary to improve the reliability of the apparatus. Moreover, in order to spread this more widely, reduction in cost and improvement in productivity in production are desired.

  One of the most important points to realize these is that the electrode, which is the most important element when performing electrochemical measurements, is various in terms of the form, material, and manufacturing method, including cost. Whether it can be adapted to actual manufacturing.

  About the form of an electrode, it is necessary for a measurement electrode to be able to be made into various shapes according to a use. For example, the measurement electrode is not a flat surface but a curved surface, thereby improving compatibility with various apparatuses.

  Also, the electrode surface must be electrochemically stable. For example, when adopting a structure in which an electrode formed by partially coating a conductive material with an electrochemically inactive conductive material is supported by an insulating material so that the portion not coated with the conductive material is covered When the liquid enters between the insulating material and the electrode, the electrochemically unstable conductive material comes into contact with the liquid. As a result, corrosion or the like of the conductive material occurs, and measurement cannot be performed with sufficient reliability. In addition, even if it is possible to prevent liquid from entering between the insulating material and the electrode, if the coating made of a conductive material is thin and pinholes cannot be avoided at the manufacturing stage, sufficient reliability is still possible. Cannot be measured under

  When the electrochemically inactive conductive material is coated on the nonconductive material, no problem such as corrosion occurs. However, in this case, a current that is large enough to ensure the accuracy of amperometry or coulometry measurement cannot be applied unless the coating made of the conductive material is formed to be considerably thick.

  Generally, noble metals such as gold and platinum are selected as the electrochemically stable conductive material. Since these substances are very expensive, they are formed as a thin film on a substrate and formed into an electrode shape by patterning. However, in order to avoid pinholes, it is necessary to ensure a certain film thickness, so that even a thin film has a high cost.

  On the other hand, as described in Patent Document 6, carbon can be used as an electrochemically stable and low-cost material. However, carbon is a material that is extremely difficult to process, and a thick and dense layer cannot be formed by vapor deposition or printing. For this reason, carbon has hardly been considered for use as an electrode of a biosensor.

  By the way, the general manufacturing method of the electrode which is a conductor can be distinguished into subtractive processing and additive processing. As subtractive processing, (1) physical processing such as cutting, polishing, molding, and laser processing is applied to an integral conductive material that is plate-shaped, linear, or massive, or chemical etching or the like is performed. (2) forming a layer made of a conductive material on an insulating substrate with a relatively large area and subjecting it to physical processing or chemical processing to form the shape of the electrode. And the method of doing. As additive processing, (3) a method of forming a layer made of a conductive material on an insulating substrate into a shape of an electrode by a method such as printing, and (4) forming a thin layer made of a conductive material on a conductive substrate, Is covered with a partially opened mask, electrode material is deposited thickly in the opening, and then the mask and the conductive film thereunder are removed.

  The electrodes obtained by the methods (1) to (4) can be partially covered with an insulating material such as a resin. Further, another metal can be deposited on the electrode surface by a film forming method such as plating or vapor phase growth.

  The above-described methods (1) to (4) are useful for producing an electrode having a surface made of metal. However, the production of carbon electrodes using these methods has significant limitations as described below.

  When a carbon electrode is obtained by method (1), chemical processing can hardly be used. In order to obtain a carbon electrode by the method (1), physical processing is performed on a material made of a carbon material such as glassy carbon, boron-doped diamond, and graphite. Therefore, with such a method, it is difficult to improve productivity by processing minute electrodes and batch processing.

  In order to obtain the carbon electrode by the method (2), conductive carbon such as graphite, graphene and carbon nanotubes is deposited on the entire surface of the insulating substrate by vapor deposition, and a necessary portion of the obtained layer is masked. Cover and dry etch. However, it is difficult to increase the film thickness of the carbon layer formed by the vapor deposition method.

  In order to obtain a carbon electrode by the method (3), a carbon paste is printed or an opened mask is formed, and carbon nanotubes, graphene, or the like is vapor-phase grown in the opening. However, since an electrode formed by carbon paste printing always has a gap between carbon particles, there is a problem of decrease in conductivity and penetration of liquid into the electrode material, which is suitable for highly reliable applications. No.

  In order to obtain a carbon electrode by the method (4), the vapor phase growth method is used as in the method (2). Therefore, as described above, it is difficult to form the carbon layer with a large film thickness.

  On the other hand, in the laminated structure of insulating substrate / conductive layer / first carbon layer / second carbon layer described in Patent Document 6, a conductive layer / carbon layer is provided on a flat insulating substrate, so that it is used as an electrode. In some cases, complicated processes such as dry etching using a resist and lift-off had to be performed in order to pattern the shape. In the vapor phase growth method, it is unrealistic to form the carbon layer with a sufficient film thickness (for example, 1 μm or more). Further, in the vapor phase growth method, a film having a uniform film thickness can be formed on a flat substrate. However, for a substrate having a complicated shape such as a previously deformed substrate, a film having a uniform film thickness can be formed. It is difficult to form a carbon layer.

  As a method for forming the carbon layer, in addition to the vapor phase growth method, there are a carbon paste printing, a glassy carbon or diamond polishing process, and a method in which various carbon materials are mixed with a polymer and applied. However, in any of these methods, it is difficult to form an electrode having a complicated shape. Biosensors have restrictions on the shape of the electrode for various reasons, and thus there is a potential demand for enabling the formation of a carbon electrode having a complicated shape.

  By the way, when an electrochemically stable and low-cost carbon electrode is to be applied to an electrochemical sensor including a control device / processing device as disclosed in Patent Documents 7 and 8, the carbon electrode and its surroundings are used. It is conceivable that the electrical contributions of the resistance, capacitance, and inductor component in the electrode portion affect the balance of the entire device. Therefore, for such a system, the carbon electrode part and its connecting part are required to have relatively high conductivity and not include unnecessary capacitance and inductor components. In an electrode manufactured by carbon paste printing, resistance becomes large and compatibility is deteriorated particularly when a fine wiring is formed.

  As described above, the existing electrochemical sensors follow the progress of medical technology in the future, improve the reliability as a device, and in order to reduce the cost and improve the productivity so that it can be widely spread. There are many challenges.

  An object of this invention is to provide the biosensor, the manufacturing method of a biosensor, and the biosensing apparatus which were excellent in reliability.

  According to the first aspect of the present invention, the biosensor has a first surface having a measurement electrode in contact with a sample liquid and a second surface having a lead wire intended to be connected to an external device. The first surface is provided with two or more measurement electrodes, and the second surface is made of an insulating material having excellent waterproof properties so that the sample liquid does not come into contact with the second surface. The support separates the first surface and the second surface, and the measurement electrodes installed on the first surface are electrically connected to the corresponding lead wires installed on the second surface. One or more of the measurement electrodes installed on the first surface include a base having a metal surface and a protective film covering at least a part of the surface, wherein the protective film comprises: A continuous film made of carbon and having a thickness of 1 μm or more.

  According to the second aspect of the present invention, the biosensor has a first surface having a measurement electrode in contact with a sample liquid and a second surface having a lead electrode intended to be connected to an external device. The first surface has two or more measurement electrodes, the second surface has two or more extraction electrodes, and the second surface has the sample liquid. The measurement electrode placed on the first surface is separated from the first surface and the second surface by the support made of an insulating material having excellent waterproof properties so that the first electrode and the second electrode are not in contact with each other. Electrically connecting to the corresponding extraction electrode provided on the second surface, wherein at least one of the measurement electrodes provided on the first surface has a base having a metal surface, and A protective film covering at least a part of the surface, the protective film is made of carbon and It is a continuous film having a μm or more thickness.

  According to the third aspect of the present invention, in the method for producing a biosensor, a base having a surface made of metal is coated with a protective layer made of carbon by plating, and at least a part of the surface is 1 μm. A step of forming an electrode having the above thickness to obtain an electrode and a step of supporting a support by two or more electrodes including the electrode are included.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in reliability and the biosensor which can be continuously analyzed while updating an analysis liquid, the manufacturing method of a biosensor, and the biosensing apparatus used with a biosensor are provided.

The figure which shows schematically the biosensor which concerns on 1st Embodiment of this invention. 1 schematically shows a reading apparatus according to a first embodiment of the present invention. The block diagram which shows the structure of the biosensor and reader shown to FIG. 1A and 1B. The figure which shows schematically the biosensor which concerns on 2nd Embodiment of this invention. The figure which shows schematically the biosensor which concerns on 2nd Embodiment of this invention. The figure which shows schematically the biosensor which concerns on 2nd Embodiment of this invention. The figure which shows schematically the biosensor which concerns on 3rd Embodiment of this invention. The figure which shows schematically the biosensor which concerns on 3rd Embodiment of this invention. The figure which shows schematically the biosensor which concerns on 3rd Embodiment of this invention. The figure which shows the 1st process in manufacture of the biosensor of this invention. The figure which shows the 1st process in manufacture of the biosensor of this invention. The figure which shows the 1st process in manufacture of the biosensor of this invention. The figure which shows the 2nd process in manufacture of the biosensor of this invention. The figure which shows the 3rd process in manufacture of the biosensor of this invention. The figure which shows the 4th process in manufacture of the biosensor of this invention. The figure which shows the 4th process in manufacture of the biosensor of this invention. The figure which shows the 5th process in manufacture of the biosensor of this invention. The figure which shows the 5th process in manufacture of the biosensor of this invention. The figure which shows an example of the structure of the reading electrode of this invention. The figure which shows an example of the structure of the reading electrode of this invention. The figure which shows an example of the structure of the reading electrode of this invention. The figure which shows an example of the structure of the reading electrode of this invention. The figure which shows an example of the structure of the electrode for a measurement of the biosensor in this invention. The figure which shows an example of the structure of the electrode for a measurement of the biosensor in this invention.

  Hereinafter, embodiments of the present invention will be described.

  The biosensor according to the embodiment can solve one or more of the problems described above. The biosensor is sometimes referred to as a biosensor or a biosensing electrode.

  The biological sensor according to the embodiment uses, for example, a numerical value serving as an index for grasping the characteristics and state of a living body, using a liquid collected from the living body or containing a minute living body as a liquid sample. Is a biosensor that is obtained ex vivo and electrically transmitted to the outside. Alternatively, the biological sensor described below uses an in-vivo liquid as a liquid sample, and acquires an in vivo (in vivo) numerical value serving as an index for grasping the characteristics and state of the living body. And a biosensor that electrically transmits it to the outside.

  Two or more electrodes are used to acquire information by an electrochemical method. The two or more electrodes are, for example, any of a pair of measurement electrodes, a pair of measurement electrodes and a reference electrode, and a combination of a pair of measurement electrodes and a reference electrode.

  At the time of measurement, these electrodes are brought into contact with the sample. The sample is, for example, a liquid sample. As the liquid sample, for example, blood, urine, sweat, tears, saliva, sebum, lymph fluid, gastric fluid, feces, semen, or nasal fluid, or a solution obtained by diluting it with a liquid such as water is used.

  When two or more electrodes are a pair of measurement electrodes, a voltage is applied or a current is passed between the paired measurement electrodes, and a current or potential corresponding to the voltage or current is measured. To do. When the current is measured, if this measurement is continuously performed, the amount of electricity can be obtained by integrating the current with time.

  When two or more electrodes are a pair of a measurement electrode and a reference electrode, a potential difference between the measurement electrode and the reference electrode is measured.

  When two or more electrodes are a combination of a pair of measurement electrodes and a reference electrode, the potential difference between the reference electrode and one measurement electrode is kept constant, and the current flowing between the measurement electrodes is measured. To do. Alternatively, a constant current is passed between the measurement electrodes, and the potential difference between the reference electrode and one of the measurement electrodes is measured.

  From the measured values thus obtained, a numerical value that becomes a biomarker such as a concentration in the liquid sample is obtained.

  The biosensor according to the embodiment employs a structure in which one or more electrodes include a base having a metal surface and a protective layer covering at least a part of the surface. The protective layer is sometimes referred to as a protective film. This protective layer is a continuous film made of carbon and having a thickness of 1 μm or more.

Carbon is electrochemically inert. Therefore, even if this protective layer is brought into contact with a living body or a liquid, it is difficult to cause deterioration.
Moreover, since carbon is electrochemically inactive, it is stable to living organisms. Therefore, this protective layer has a small influence on the living body when it is brought into contact with the living body.

  Moreover, the protective layer is a continuous film as described above. That is, this protective layer is not a porous film or a film composed of carbon particles, but a dense film, unlike those formed using carbon paste. And since this protective layer has sufficient thickness, possibility that a pinhole will exist is low. Therefore, this electrode has a very low possibility that the liquid penetrates the protective layer and comes into contact with the substrate.

In addition, as described above, this protective layer is not a porous film or a film composed of carbon particles, but a continuous film. Therefore, this protective layer has high conductivity.
Therefore, this biosensor is excellent in reliability and can be measured with high accuracy.

  Carbon is a cheaper material than precious metals, and its price fluctuation is small. Therefore, this biosensor can be manufactured at a relatively low cost.

  As is clear from the above description, it is preferable that the protective layer covers at least the entire region that can be contacted by the measurement target on the surface.

  Since the protective layer is made of carbon, it is difficult to join the lead wire to the protective layer using solder or the like. Therefore, as a means for outputting a signal to the outside without providing a lead line, a means for bringing a conductive metal into physical contact with an electrode having a protective film and making it electrically conductive can be taken.

  Specifically, when providing a lead electrode on the measurement electrode, for example, a protective layer may be provided on the entire surface of the metal base, and one end of the base may be used as the measurement electrode and the other end may be used as the lead electrode. it can. The electrical connection with the extraction electrode can be achieved by preparing a reading device having a reading electrode and physically contacting the extraction electrode and the reading electrode.

  At this time, since the carbon plating film covering the extraction electrode does not form an oxide film, the contact resistance does not increase even by physical contact, and conduction is easily obtained.

  On the other hand, in consideration of wear resistance and the like, the metal surface of the base is partially exposed to the extraction electrode portion, and this portion is brought into contact with the reading electrode of the reading device, thereby having a protective film. The substrate can also be connected to the reading electrode via a lead electrode.

  In this case, a protective layer is formed on the entire surface of the substrate made of metal, and then the edge of the substrate is cut together with the protective layer thereon. Thereby, the metal is exposed at the position of the cut surface. For example, a part of a plate having a surface made of metal is removed to obtain a structure including a base and a support portion connected thereto. Next, a protective layer is formed on the metal surface of the structure. Thereafter, the substrate is separated from the support portion. Then, a readout jig is brought into contact with the exposed portion of the metal surface of the base, and one end of the lead wire is joined.

  Alternatively, first, a mask is formed on a part of the metal surface of the substrate. Next, a protective layer is formed on the entire exposed portion of the metal surface. Thereafter, the mask is removed from the metal surface. Then, a readout jig is brought into contact with the exposed portion of the metal surface of the base, and one end of the lead wire is joined.

  In any method, it is preferable that the protective layer covers the entire surface except for the joint portion between the metal surface of the substrate and the lead wire.

  In any method, the exposed metal surface of the substrate can be coated with a corrosion-resistant metal or a slidable metal by partial plating or the like. .

  Further, since this method forms a protective layer made of carbon by plating, the protective layer can be formed evenly on the side wall of the substrate having a complicated shape. That is, this method has an advantage that the metal surface is not exposed.

  The reading device further includes a processing unit (or information processing unit) that is electrically connected to two or more electrodes of the biosensor and generates information related to the measurement target from a current flowing between the electrodes or a voltage between the electrodes. You may go out. In this case, the reading device may further include an output unit that outputs information to the outside of the reading device. Further, the reading device may further include a power supply unit and a control unit.

The protective layer described above is formed by, for example, a plating method. For example, it is possible to use a carbon plating technique that is implemented by I'M Sep Co., Ltd. using molten salt electrolysis. This technique uses a anodic oxidation reaction (see the following reaction formula) of carbide ions (C22−) added to a molten salt such as chloride, so that the surface of the material to be treated is very dense. A carbon layer is formed.
C ₂ ²⁻ → 2C (plating film) + 2e ⁻
The protective layer thus obtained typically includes a graphite structure, and is composed of a mixture of carbon atoms forming sp2 bonds and carbon atoms forming sp3 bonds. The details of this method are described in JP2009-120860.
In addition, as another method for obtaining a protective film made of carbon by utilizing molten salt electrolysis, there is a method of adding carbonate to the molten salt and reducing the material to be treated as a cathode. This reaction can be represented by the following reaction formula.
CO ₃ ²⁻ + 4e ⁻ → C + 3O ₂ ⁻
Details of this method are described in JP-A-2006-169554.

  As another method of forming a protective layer made of carbon on the surface of the substrate by using an electrochemical reaction, conductive carbon particles are contained in an electrolytic solution containing a metal to be deposited so that the substrate becomes a cathode. There is a method of forming a protective layer by causing an electrochemical reaction.

  As the carbon particles, for example, those containing a graphite structure and composed of a mixture of sp2 structure and sp3 structure are used.

  As a metal to be deposited, for example, in addition to noble metals such as gold, platinum, silver, rhodium and ruthenium, iron, nickel, cobalt, copper, chromium, zinc or alloys thereof can be used in an electrolytic plating solution made of an aqueous solution. A thing can be selected suitably. Alternatively, when a non-aqueous dimethyl sulfone bath is used, aluminum can be used as the metal to be deposited.

  When the liquid sample to be subjected to biological sensing is acidic or alkaline or contains a compound capable of complexing the metal to be deposited at a relatively high concentration, it is preferable to use a noble metal. When the liquid sample is neutral and does not contain a compound capable of complexing the metal to be deposited, various selections are possible. Whether it can be used as a metal to be deposited may be confirmed in advance by experiments.

  Strictly speaking, the protective layer obtained by such a method is not a pure carbon layer because the metal to be deposited is deposited surrounding the carbon particles. However, it can be used by selecting the metal to be deposited in accordance with the target of biological sensing.

  As described above, the protective layer is formed by, for example, a plating method. According to the plating method, a thick protective layer can be formed. For example, a protective layer having a thickness of 1 μm to 5 μm can be formed.

  Further, according to the plating method, a protective layer having a uniform thickness can be formed even when the substrate has a complicated shape. For example, when the substrate has a curved or bent shape, the protective layer can be formed so as to cover at least a region of the metal surface of the substrate corresponding to a portion where the substrate is curved or bent. When the base has first and second main surfaces parallel to each other and end surfaces extending along the edges, the protective layer includes the entire first main surface and the second main surface. And at least a part of the end face.

  Further, according to the plating method, the protective layer can be formed at a relatively low cost and with high productivity.

Then, according to the plating method, it is easy to form a protective layer on the entire surface of the substrate.
Therefore, according to this technology, it is possible to follow the advancement of medical technology in the future, improve the reliability as a device, and achieve cost reduction and productivity improvement.

  When a protective layer made of carbon is formed by a plating method, this protective layer typically includes a graphite structure, and includes carbon atoms forming sp2 bonds and carbon atoms forming sp3 bonds. It consists of a mixture of

  In order to improve the sensitivity of biological sensing measurement, the surface of the protective layer may be modified. For example, when analyzing blood glucose, glucose oxidase or an osmium compound may be immobilized on the surface of the protective layer.

  Hereinafter, embodiments will be described with reference to the drawings. In the accompanying drawings, the same reference numerals are assigned to components that perform the same or similar functions in order to omit redundant description. The embodiment described below shows an example of the above description.

<First Embodiment>
FIG. 1A is a perspective view schematically showing a biosensor according to a first embodiment of the present invention. FIG. 1B is a perspective view schematically showing the reading apparatus according to the first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the biosensor and reading device shown in FIGS. 1A and 1B.

The biosensor 100 is a device that uses a liquid collected from a living body as the sample 3, that is, a device that is used ex vivo. Note that the sample 3 may be a measurement sample, a body fluid sample, a sample body fluid, or a sample liquid.
Here, an example of the biosensor 100 configured as follows will be described. The biosensor 100 has a first surface having an electrode in contact with the sample 3 and a second surface having an electrode intended to be connected to an external device, and the first surface has two or more electrodes. And the second surface has two or more electrodes. Furthermore, in the biosensor 100, the support body 1 made of an insulator separates the first surface and the second surface so that the sample 3 does not contact the second surface. The electrodes installed on the first surface are electrically connected to the corresponding electrodes installed on the second surface. One or more of the electrodes placed on the first surface include a base having a surface made of metal and a protective film covering at least a part of the surface of the base. The protective film is a continuous film made of carbon and having a thickness of 1 μm or more. The protective film covers at least the entire area where the sample 3 can come into contact.

  In the biosensor 100 shown in FIGS. 1A and 2, the electrode unit 13 is embedded in the support body (support body) 1, and the first surface of the support body 1 is measured at the electrode unit 13. The electrodes 10a and 10b are exposed, and the lead electrodes 11a and 11b are exposed on the second surface. The biological sensor 100 is for contacting the sample 3 which is a body fluid so as to cover all of the exposed measurement electrodes 10a and 10b, and obtaining information on the body fluid. The biosensor 100 can draw the electrical signal to the outside to the electrodes 11a and 11b that are electrically connected by bringing the body fluid into contact with the measurement electrodes 10a and 10b.

  At least one of the electrode portions 13 includes a base and a protective layer. Here, as an example, it is assumed that all of the electrode portions 13 used in the biosensor 100 include a base and a protective layer described below.

  The substrate has a surface made of metal. The base is made of, for example, a metal or a composite of a metal and an insulator such as a resin. As the metal, stainless steel or iron can be used.

  In the structure shown in FIG. 1A, the base body has first and second main surfaces parallel to each other and end surfaces extending along the edges thereof. Here, the base is a rod-shaped member having a circular shape at both ends.

  The protective layer covers at least part of the surface of the substrate made of metal. The protective layer is a continuous film made of carbon as described above. Here, as an example, the protective layer covers the entire first main surface, a part of the second main surface, and the entire end surface of the substrate.

  The support body 1 supports the measurement electrodes 10a and 10b and the extraction electrodes 11a and 11b so as to be separated from each other. The support body 1 is made of an insulating material at least in contact with the measurement electrodes 10a and 10b and the extraction electrodes 11a and 11b. As the insulator, for example, medical plastic or ceramic can be used.

Here, an example of a reading device (biosensing device) 200 configured as follows will be described. The reading device 200 is electrically connected to two or more electrodes (for example, extraction electrodes 11a and 11b) installed on the second surface of the biosensor 100, and direct current, alternating current, or both are applied between the electrodes. And a signal processing unit 2a that generates information on the sample 3 in contact with the first surface (for example, the surface on which the measurement electrodes 10a and 10b are provided) from the current flowing between the electrodes or the resistance between the electrodes. In connection between the reading device 200 and the biosensor 100, the electrodes (for example, the extraction electrodes 11a and 11b) installed on the second surface and the electrodes (for example, the reading electrodes 12a and 12b) of the reading device 200 are energized by sliding. .
A reader 200 shown in FIG. 1B has a reader main body 2 having a hollow structure. The reading device 200 may incorporate an electronic component shown in FIG. 2 and a battery (not shown). Note that the measurement electrode 10 in FIG. 2 collectively refers to the measurement electrodes 10a and 10b. The extraction electrode 11 is a general term for the extraction electrodes 11a and 11b. The read electrode 12 is a general term for the read electrodes 12a and 12b.

  The reading device 200 includes a signal processing unit (or processing unit) 2a, a control unit 2b, an output unit 2c, and a power supply unit 2d.

  The signal processing unit 2 a and the control unit 2 b are electrically connected to the electrode unit 13. The control unit 2b applies a voltage between the extraction electrodes 11a and 11b and the measurement electrodes 10a and 10b through the reading electrodes 12a and 12b, or allows a current to flow between them. Similarly, the signal processing unit 2a generates information on the measurement sample from the magnitude of the current flowing between the measurement electrodes 10a and 10b or the potential difference between them.

  The voltage applied between the measurement electrodes 10a and 10b by the control unit 2b or the magnitude of the current flowing between them may be, for example, constant or may be changed in a pulse wave shape, depending on the passage of time. It may be increased or decreased linearly, and may be changed over time according to a certain function.

  For example, the signal processing unit 2a converts the magnitude of the current flowing between the measurement electrodes 10a and 10b and the potential difference between them into a signal that can be easily transmitted to the output unit 2c. The signal processing unit 2a may further perform averaging, calculation according to a certain model, or the like.

  The power supply unit 2d is electrically connected to the signal processing unit 2a, the control unit 2b, and the output unit 2c. The power supply unit 2d appropriately distributes the electric power supplied from the battery to other elements of the electronic components in the reading device main body 2. Alternatively, it may itself include a battery.

  The output unit 2c is electrically connected to the signal processing unit 2a. The output unit 2c transmits the information generated by the signal processing unit 2a to an external device using wireless or wired communication.

  The signal processing unit 2a, the control unit 2b, the output unit 2c, and the power supply unit 2d are formed on one or more semiconductor chips. All of these may be formed on a single semiconductor chip, or they may be formed on separate semiconductor chips.

  A battery (not shown) is electrically connected to the power supply unit 2d. The battery supplies power to the power supply unit 2d.

  As described above, the biosensor 100 performs liquid analysis by bringing the liquid measurement sample into contact with the measurement electrodes 10a and 10b. Examples of the liquid include, but are not limited to, body fluid samples such as blood, sweat, and urine.

  As described above, since it is possible to physically disassemble the biosensor 100 and the reading device 200, it is possible to use the biosensor 100 only in a disposable manner as necessary. Not only is there a merit, but also the possibility that the electronic device included in the reading apparatus 200 directly touches the sample liquid becomes low, so that the possibility of failure can be reduced.

  In addition, by manufacturing the electrode portion 13 by bending a plate-like metal, for example, processing is easier than when a columnar metal having the same length as the side wall is embedded, or when a columnar electrode is used. Although there is a possibility of slipping and coming off from the support body 1, it is difficult to cause displacement by embedding a bent metal plate in the support body 1, and the sample body fluid cannot be easily removed. There are advantages.

Second Embodiment
3A, 3B and 3C are perspective views schematically showing a biosensor according to a second embodiment of the present invention.
The cylindrical biological sensor 300 is for obtaining information related to a living body by introducing a body fluid into the cylindrical support body 1.

  The biosensor 300 has a hollow columnar shape, and the hollow portion penetrates the cylinder. That is, the support body 1 penetrates from the first end surface orthogonal to or substantially orthogonal to the longitudinal direction to the second end surface facing the first end surface. The shape of the biosensor 300 is not limited to this. For example, the biosensor 300 may have a cubic shape, or may have a spherical shape or a spheroid shape.

  The reading electrodes 12a and 12b installed in the reading device 400 shown in FIG. 3B are connected to the extraction electrodes 11a and 11b of the biosensor 300 to obtain and analyze electrical information related to body fluid, and transmit the results to the outside. To do. Thus, body fluid information can be acquired by continuously introducing body fluid into the inside of the biosensor 300 (through hole formed in the support body 1). Information on body fluid may be stored in the reading device 400 and transmitted to the external device later by wired or wireless.

  As shown in FIG. 3C, when the biosensor 300 is used, for example, a blood vessel 500 is connected to a through-hole formed in the support body 1 and blood is continuously introduced to analyze the body fluid. . In this case, the biosensor 300 can measure and acquire the pH, conductivity, and blood glucose level of blood, for example.

Here, an example of the biosensor 300 configured as follows will be described. In the biosensor 300, the support body 1 has the first surface (the surface on which the measurement electrodes 10a and 10b are provided) on the inner side and the second surface (the surface on which the extraction electrodes 11a and 11b are provided). ) On the outside, and has connecting portions for connecting tubes to both ends of the cylindrical support body 1. The sample 3 is introduced into the cylinder of the support body 1.
The biosensor 300 is substantially the same as the biosensor 100 described with reference to FIGS. 1A, 1B and 2 except that the following configuration is adopted. That is, in this biosensor 300, the support body 1 supports both the measurement electrodes 10a and 10b on one surface. The measurement electrodes 10 a and 10 b face inward with respect to the cylindrical support surface of the support body 1. That is, the measurement electrodes 10 a and 10 b are provided on the inner surface that forms the through hole of the support body 1. Furthermore, in this biosensor 300, the support body 1 supports both the extraction electrodes 11a and 11b on one surface. The lead electrodes 11 a and 11 b face outward with respect to the cylindrical support surface of the support body 1. That is, the extraction electrodes 11 a and 11 b are provided on the outer surface of the support body 1. When this structure is adopted, it is possible to easily connect to the reader (analyzer) 400 simply by connecting to existing piping.

  Further, as shown in FIG. 13, the shape of the measurement electrode 10 may be, for example, an annular electrode (formed along the side wall) covering the inner wall of the cylinder (support body 1), or as shown in FIG. Alternatively, the electrode may have a comb shape. In the former case, even with a small amount of body fluid, the measurement electrode 10 can be reliably touched, and in the latter case, the contact area with the body fluid can be increased to enable highly accurate analysis.

  The biosensor 300 allows the sample liquid to flow continuously, and performs the analysis at a predetermined periodic timing or performs the analysis at all times. For example, the analysis result is temporarily stored in the reading device 200 and transmitted to an external device using wireless or wired communication. Thereby, it becomes possible for a patient and a doctor to grasp a measurement result.

<Third Embodiment>
4A, 4B and 4C are perspective views schematically showing a biosensor according to a third embodiment of the present invention.
Here, an example of the biosensor 600 configured as follows will be described. In the biosensor 600, the support body 1 is cylindrical, and at least one opening is closed.

  The cylindrical biosensor 600 has a cup shape in which one of the cylindrical support bodies 1 is closed. That is, the support body 1 is formed with a concave portion in the longitudinal direction at the first end surface orthogonal or substantially orthogonal to the longitudinal direction, and is closed at the second end surface facing the first end surface. The biological sensor 600 is for obtaining information related to the living body by introducing body fluid into the cup or obtaining information related to the living body by applying the body fluid to the outside of the cup shape.

An example of the biosensor 600 configured as follows will be described with reference to FIG. 4B. In the biological sensor 600, in the cylindrical support body 1, the first surface (the surface on which the measurement electrode 10 is provided) is on the inner side, and the second surface (the surface on which the extraction electrode 11 is provided). Is arranged on the outside.
The biosensor 600 is provided with the measurement electrode 10 and the extraction electrode 11 as follows, for example. The measurement electrode 10 faces inward with respect to the cylindrical support surface of the support body 1. That is, the measurement electrode 10 is provided on the inner surface forming the recess of the support body 1. The lead electrode 11 faces the outside with respect to the cylindrical support surface of the support body 1. That is, the extraction electrode 11 is provided on the outer surface of the support body 1. The reading device 700 is provided with the reading electrode 12 as follows, for example. The reading device 700 is formed with a recess having a shape into which the biosensor 600 can be fitted. The reading electrode 12 is provided in a concave portion formed in the reading device 700 at a position where the reading electrode 12 comes into contact with the extraction electrode 11 when the biosensor 600 is fitted.
Accordingly, in FIG. 4B, for example, urine or blood is introduced into the cup of the biosensor 600, and the cylindrical biosensor 600 is installed in the reader 700, whereby information about the living body can be obtained through the read electrode 12. become.

An example of the biosensor 600 configured as follows will be described with reference to FIG. 4C. The biological sensor 600 has a cylindrical support body 1 in which the first surface (the surface on which the measurement electrode 10 is provided) is on the outside and the second surface (the surface on which the extraction electrode 11 is provided). Is placed inside.
The biosensor 600 is provided with the measurement electrode 10 and the extraction electrode 11 as follows, for example. The measurement electrode 10 faces outward with respect to the cylindrical support surface of the support body 1. That is, the measurement electrode 10 is provided on the outer surface of the support body 1. The extraction electrode 11 faces inward with respect to the cylindrical support surface of the support body 1. That is, the extraction electrode 11 is provided on the inner surface forming the concave portion of the support body 1. The reading device 800 is provided with the reading electrode 12 as follows, for example. The reading device 800 has a convex portion that can be fitted into the concave portion of the biosensor 600. The reading electrode 12 is provided at a position where the convex portion formed in the reading device 800 comes into contact with the extraction electrode 11 when the concave portion of the biosensor 600 is fitted.
Thereby, in FIG. 4C, the biosensor 600 is used by being inserted into an electrode provided in the toilet bowl. For example, it is possible to obtain biometric information immediately by the reading device 800 by placing the urine on the outside of the cup-shaped biosensor 600 after being installed in a toilet.

The biosensor 600 is manufactured, for example, by sequentially performing the following steps. A biosensor having a shape other than the biosensor 600 is similarly manufactured.
The manufacturing method will be described in detail below. The substrate 131 having a surface made of metal is coated with a protective layer 17 made of carbon by a plating method so as to cover at least a part of the surface and have a thickness of 1 μm or more. Forming the electrode to obtain an electrode, and supporting the support body 1 with two or more electrodes including the electrode. Further, the manufacturing method includes a step of deforming the base 131 prior to the step of obtaining the electrode having the protective layer 17. Further, the manufacturing method includes a step of obtaining a structure including a base 131 and a support portion 14 connected to the base 131 by removing a part of a plate having a metal surface, and a step of obtaining an electrode. And a step of separating the base 131 from the support portion 14.

(First step)
In the first step, a metal plate 900 shown in FIG. 5A is prepared. FIG. 5B shows a cross section at X1 and X2 in FIG. 5A. The metal plate 900 includes a base 131 that constitutes the electrode portion 13 and a support portion 14 that supports the support. The metal plate 900 is provided with slits 15. The base 131 and the support part 14 are isolated from each other via the slit 15 except for the connection part 16 connecting them. At this time, it is important that the connection portion 16 is not connected to a portion that will later become the measurement electrode 10 or the extraction electrode 11.

  In selecting the material of the metal plate 900, the ease of forming, the strength after forming, the thermal expansion characteristics, the melting point, the ease of forming an oxide film, the price, and the protective layer made of carbon on the surface is electrochemical. Taking into account the formation of the method. Since a protective layer made of carbon is formed on the substrate 131, the electrochemical stability of the substrate 131 itself is not important. As a material of the metal plate 900, for example, nickel, copper, iron, or an alloy thereof, or stainless steel can be used.

  The substrate 131 is plate-shaped here, but may have other shapes such as a rod shape. Further, the metal plate 900 is subjected to press working such as bending or drawing to deform the base 131 as shown in FIG. 5C. At this time, although not shown, the base 131 is kept connected to the support portion 14 via the connection portion 16. The slit 15 can be formed by, for example, shearing, chemical etching, blasting, laser processing, or a combination thereof. For example, a plurality of processes may be combined in consideration of productivity and accuracy, such as bending a chemically etched material with a press and further cutting a part with a laser.

(Second step)
In the second step, a protective layer 17 made of carbon is formed on the entire surface of the metal plate 900 as shown in FIG. The protective layer 17 is formed by, for example, a plating method.

(Third step)
In the third step, as shown in FIG. 7, the base portion 131 is cut together with the protective layer 17 thereon and the connection portion 16 with the support portion 14. For example, the connection portion 16 between the base 131 and the support portion 14 is cut using a laser, a microcutter, or the like.

  As described above, the electrode part 13 composed of the base 131 and the protective layer 17 is obtained. The region located on the inner cut surface of the surface of the base 131 is exposed, but the other region is covered with the protective layer 17.

(4th process)
In the fourth step, the electrode portion 13 is temporarily fixed as shown in FIGS. 8A and 8B. Here, the measurement electrode 10 and the extraction electrode 11 provided in the electrode portion 13 are arranged in parallel. Although not drawn here, the electrode portions 13 are arranged in the cavity of the mold so that their exposed main surfaces are in contact with the mold.

(5th process)
In the fifth step, a resin is injected into a capacity not shown. The support body 1 is obtained by curing this resin. Subsequently, the biosensor of FIG. 9A is obtained by disassembling the mold. FIG. 9B shows the portion including the electrode portion 13 cut out.

  The support body 1 needs to be stable with respect to the liquid sample used for biological sensing. As a material for the support body 1, an organic resin is suitable.

The liquid sample should not enter between the support body 1 and the base 131 so that the effective area of the measurement electrode 10 is constant. Further, from the viewpoint of preventing the corrosion of the base 131, the liquid sample should be prevented from coming into contact with the part separated from the support part 14 in particular. Therefore, it is preferable to form the support body 1 so as to embed these connection portions 16 or to form the protective layer 17 on the connection portions 16.
As described above, for example, the biosensor shown in FIGS. 1, 3, and 4 is obtained.

  Although not shown, the biosensor can be provided with a reference electrode. As the reference electrode, for example, a silver / silver chloride electrode can be used. Such a reference electrode is obtained by preparing a part having a surface made of metallic silver and chlorinating the surface to produce silver chloride. By incorporating this reference electrode in the same manner as the substrate 131, a biosensor having the reference electrode can be obtained.

<Fourth embodiment>
The reading apparatus 200 shown in FIGS. 10A and 10B has an analysis unit. FIG. 10B shows a cross-sectional view in a state where the biosensor 100 and the reading device 200 are electrically connected. As shown in FIG. 10A, the reading electrodes 12 a and 12 b have a convex shape, so that the reading electrode 11 can be reliably contacted.

  The reading electrode 12 may have a spring shape shown in FIG. 11 or a leaf spring shape shown in FIG. The read electrode 12 is not limited to this. The electrode material is preferably one in which the base 131 is coated with carbon. However, for example, a metal plate obtained by applying gold plating to copper to obtain corrosion resistance or conductivity may be used. By connecting the reading electrode 12 to the analyzing unit of the reading device 200 shown in FIG. 2, it becomes possible to analyze the electrical signal of the measuring electrode 10 provided in the biosensor 100. Here, the reading apparatus 200 has been described as an example, but the present invention can be similarly applied to other reading apparatuses.

  The reading device 200 can be manufactured by a general method for manufacturing a mechanical device, and it is not necessary to use the above-described method for manufacturing a biosensor.

  Below, the specific example of manufacture of a biosensor and the measurement using this is described.

(A) Processing of metal material A 20 mm thick stainless steel (SUS304) plate was processed to obtain a metal plate 900 shown in FIG. 5A. Specifically, this processing was performed by the following method. First, a photosensitive etching resist was applied to both surfaces of a stainless steel plate. These resist layers were subjected to pattern exposure and developed to form resist patterns on both surfaces of the stainless steel plate. Next, stainless steel was etched using these resist patterns as an etching mask. As an etchant, a ferric chloride solution was used. Then, the metal plate 900 which has the slit 15 was obtained by peeling a resist pattern. Next, bending was performed so that the base 131 was lifted with respect to the support portion 14. Here, the size of the circular portion which is an electrode of the base 131 is 3 mm in diameter, and the base 131 is bent so that the circular portion of the base 131 is in a position perpendicular to the support portion 14.

(B) Formation of Protective Layer Next, a continuous film made of carbon having a thickness of 3 μm was formed as the protective layer 17 shown in FIG. 6 on the entire surface of the metal plate 900 by plating. Specifically, the protective layer 17 was formed by immersing the metal plate 900 in a molten salt containing calcium carbide (LiCl—KCl—CaCl2: 500 ° C.) and performing anodic polarization.

(C) Temporary Arrangement of Electrodes Next, the base 131 on which the protective layer 17 was formed was separated from the support portion 14. Specifically, the base 131 was cut from the support 14 by irradiating the connecting portion between the base 131 and the support 14 with a laser beam. Thus, the electrode part 13 comprised with the base | substrate 131 and the protective layer 17 shown in FIG. 7 was obtained.

(D) Resin mold Next, the electrode part 13 was arrange | positioned in the cavity of the metal mold | die not shown so that those exposed main surfaces might contact the wall surface of the metal mold | die not shown.

  Next, a resin was injected into the mold. By curing this resin, a biosensor 600 shown in FIG. 4A having a diameter of 20 mm, a height of 30 mm, and a thickness of the support body 1 of 3 mm was obtained.

(E) Preparation of Reading Device A reading device 700 having the reading electrode 12 shown in FIG. 4B and the analysis unit shown in FIG. 2 is prepared. The reading device 700 has a shape in which the biosensor 600 can be attached, and has a cylindrical hole having a diameter of 23 mm and a depth of 20 mm. The reading electrode 12 installed in the hole is a leaf spring type shown in FIG. Thus, the lead electrode 11 was electrically connected.

(F) Connection of parts The biosensor 600 was attached to the reading device 700 so that the lead electrode 11 of the biosensor 600 and the reading electrode 12 of the reading device 700 were brought into contact with each other.

(G) Measurement 10 μL of blood was mixed with 10 μL of physiological saline containing glucose oxidase and ferricyanide ions at a concentration of 0.01 mol / L. One minute after the start of mixing, this mixed solution was introduced into the concave portion of the biosensor 600, and a voltage of 0.5 V was applied between the reading electrodes 12a and 12b. Then, the current flowing between the reading electrodes 12a and 12b was measured 10 seconds after the start of voltage application. The current value obtained by this measurement was 1 to 10 μA when the blood glucose concentration was in the range of 10 to 500 mg / dL, and it was found that good linearity was obtained. This measurement method itself is relatively common as a method for detecting blood glucose concentration. From the above test, it was found that accurate measurement is possible even when the above-described biosensor is used.

  By using this method, it is possible to continuously measure the liquid, and it is possible to discard only the biosensor used for the measurement and use it without contaminating the analysis unit.

100, 300, 600 ... biosensor; 200, 400, 700, 800 ... reading device; 500 ... transfusion vessel; 900 ... metal plate; 1 ... support body; 2 ... reading device body; 3 ... sample; 11 ... Electrode for extraction; 12 ... Reading electrode; 13 ... Electrode portion; 14 ... Supporting portion; 15 ... Slit; 16 ... Connection portion; 17 ... Protective layer;

Claims (13)

A first surface having an electrode in contact with the sample liquid and a second surface having an electrode intended for connection to an external device;
The first surface comprises two or more electrodes,
The second surface comprises two or more electrodes,
A support made of an insulator separates the first surface and the second surface so that the sample liquid does not contact the second surface,
The electrode installed on the first surface is electrically connected to the corresponding electrode installed on the second surface;
One or more of the electrodes installed on the first surface include a base having a surface made of metal and a protective film covering at least a part of the surface,
The biological sensor, wherein the protective film is a continuous film made of carbon and having a thickness of 1 μm or more.   The biosensor according to claim 1, wherein the protective film covers at least an entire area where the sample liquid can contact.   The support has a cylindrical shape in which the first surface is provided on the inner side and the second surface is provided on the outer side, and has connection portions for connecting tubes to both ends of the cylindrical support. The biosensor according to claim 1, wherein the sample liquid is introduced into a cylinder of the support.   The biosensor according to claim 1 or 2, wherein the support is cylindrical and at least one opening is closed.   The biosensor according to claim 4, wherein in the cylindrical support body, the first surface is disposed on the outside and the second surface is disposed on the inside.   5. The biosensor according to claim 3, wherein the electrode installed on the first surface has an annular shape formed along a side wall of a cylinder.   The biosensor according to claim 1, wherein the sample liquid is blood or urine. Forming a protective film made of carbon on a substrate having a surface made of metal by plating so as to cover at least a part of the surface and have a thickness of 1 μm or more, and obtaining an electrode;
Supporting two or more electrodes including the electrode on a support;
A method for manufacturing a biosensor, comprising:   The biosensor manufacturing method according to claim 8, further comprising a step of deforming the base body prior to the step of obtaining the electrode having the protective film. Removing a part of the plate having a surface made of the metal to obtain a structure including the base and a support portion connected to the base;
After the step of obtaining the electrode, the step of separating the base from the support part;
The biosensor manufacturing method according to claim 8, further comprising:   8. The biosensor according to any one of claims 1 to 7, wherein the biosensor is electrically connected to two or more electrodes installed on the second surface, and a direct current, an alternating current, or both are applied between the electrodes. A biosensing device comprising a processing unit that generates information on the sample liquid in contact with the first surface from a current flowing between the electrodes or a resistance between the electrodes.   The biosensing apparatus according to claim 11, wherein the biosensor is connected to the electrode installed on the second surface and the electrode of the biosensing apparatus is energized by sliding.   The biosensing device according to claim 12, wherein the biosensor is used by being inserted into an electrode provided in a toilet.