JP2017093939A - Detection element, analyzer and insulin feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detection element in which an occurrence of physical damage in an analyte sensing layer is accurately suppressed or prevented even when an external load is applied to the analyte sensing layer, and an analyzer comprising the detection element and an insulin feeding device.SOLUTION: A detection element comprises a detection section 300 having a substrate 301, a conductive layer 315 being formed on the substrate 301 and comprising a working electrode and a counter electrode, sensing layer 320 formed on the conductive layer 315. Further, the sensing layer 320 includes: an analyte sensing layer 321 being formed on the conductive layer 315 and containing enzymes; an analyte adjustment layer 323 formed at an opposite side to the conductive layer 315 of the analyte sensing layer 321; and an intermediate layer 322 formed between the analyte sensing layer 321 and the analyte adjustment layer 323.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a detection element, an analyzer, and an insulin supply device.

  Along with the recent improvement in health-consciousness, blood glucose, lactic acid levels, antibody levels, and enzyme levels in body fluids such as blood, interstitial fluid, saliva, and sweat in specific individuals are measured over time to improve health. Management is carried out.

  For example, for diabetics, measuring blood glucose levels over time (monitoring) is particularly important.

  Here, diabetic patients are classified into type I and type II depending on their symptoms, but both do not have normal insulin secretion from the pancreas, which prevents the body organs from taking glucose (glucose) normally, Metabolic abnormalities cause weight loss. Furthermore, if a high blood glucose level is maintained for a long period of time, serious symptoms such as “diabetic retinopathy”, “diabetic nephropathy”, “diabetic microangiopathy”, “diabetic neuropathy”, etc. It is known that complications will develop. In order to prevent the onset of such serious complications, patients with persistent hyperglycemia are treated with insulin to administer insulin by injection to maintain blood glucose levels within the normal range. is the current situation.

  Since patients with type I diabetes have no secretion of insulin due to pancreatic disease, they must measure blood sugar levels by blood sampling several times a day (minimum before meals and 4 times before going to bed) and administer insulin. As for the timing of administration, in order to suppress an excessive increase in postprandial blood glucose level, the blood glucose level before meal is measured, the calorie of the meal amount is calculated, the dose of insulin is determined, and injection is administered before meal . In addition, what is known as an increase in blood glucose level is a symptom called a “disease phenomenon”, and the blood glucose level increases at dawn 8 to 10 hours after going to bed. However, in order to cope with this physiological phenomenon, it is necessary to wake up once before dawn, measure blood sugar level by blood sampling, and administer insulin if hyperglycemia. In this way, a normal healthy person can live a daily life without worrying about blood sugar level, but diabetic patients (especially type I diabetic patients) are forced to live while worrying about blood sugar level throughout the day. ing.

  In order to reduce the burden on the life of such a patient and a family supporting the patient, that is, in order to improve the QOL of the patient and the patient's family, development of an artificial pancreas or a device equivalent thereto is required. is the current situation. For this purpose, it is first necessary to measure / manage blood glucose levels over time (continuously) and automatically.

  For example, a device for the purpose of monitoring a glucose concentration in a patient's interstitial fluid over a long period of time by implanting a blood glucose sensor in the body (subcutaneous tissue), a so-called continuous glucose monitor (CGM) device using an enzyme reaction Proposals have been made.

  The basic principle of quantitative glucose measurement using this enzyme reaction is that gluconic acid and hydrogen peroxide are produced when glucose and oxygen are present in the vicinity of the enzyme in the presence of an enzyme (for example, glucose oxidase). Since the amount of hydrogen peroxide can be quantified by measuring the amount of current generated by electrolyzing the generated hydrogen peroxide, it is possible to calculate the amount of glucose based on this Become. By using such an enzyme reaction, it becomes possible to continuously monitor the blood glucose level by a sensor embedded in the body.

  As an analyzer (analyte sensor) using the basic principle of glucose quantitative measurement, for example, in Patent Document 1, a sensing layer in which glucose quantitative measurement is performed includes an enzyme layer (analyte sensing layer) containing an enzyme, An analyte contact layer (analyte adjustment layer) for adjusting the amount of glucose contacting the enzyme layer, and an adhesion promoter layer for improving contact and / or adhesion between the enzyme layer and the analyte contact layer What to prepare is proposed.

  However, in this analyzer, the adhesion promoter layer is composed of a monomolecular film containing a silane compound, and the thickness thereof is very thin, so that the mechanical strength is not sufficient. Therefore, when the blood glucose level sensor is implanted in the subcutaneous tissue or when the interstitial fluid penetrates into the sensing layer, an external load is applied to the enzyme layer (analyte sensing layer), resulting in physical damage. There was a problem.

JP-T-2006-502810

  One of the objects of the present invention is to provide a detection element in which physical damage in the analyte sensing layer is accurately suppressed or prevented even when an external load is applied to the analyte sensing layer. An object of the present invention is to provide an analyzer and an insulin supply device including a detection element.

Such an object is achieved by the present invention described below.
The detection element of the present invention comprises a substrate,
A conductive layer formed on the substrate;
A sensing unit having a sensing layer formed on the conductive layer,
The sensing layer includes an analyte sensing layer that senses an analyte, an analyte conditioning layer that regulates the analyte, and an intermediate layer that separates the analyte sensing layer and the analyte conditioning layer;
The conductive layer, the analyte sensing layer, the intermediate layer, and the analyte adjustment layer are arranged in this order with respect to the thickness direction.

  Thereby, even if an external load is applied to the analyte sensing layer, it is possible to accurately suppress or prevent physical damage from occurring in the analyte sensing layer.

In the detection element of the present invention, the analyte sensing layer is formed of an enzyme and other components,
The intermediate layer is preferably formed of only the other component.

  Thereby, the interface between the intermediate layer and the analyte sensing layer can be made uniform. Therefore, the measurement object that has penetrated from the analyte adjustment layer can be supplied from the intermediate layer to the analyte sensing layer without the interface between the intermediate layer and the analyte sensing layer becoming a barrier.

  In the detection element of the present invention, it is preferable that the analyte sensing layer includes the enzyme and a poly (vinyl alcohol) -styrylpyridinium compound, and the intermediate layer includes a poly (vinyl alcohol) -styrylpyridinium compound.

  As a result, both the intermediate layer and the analyte sensing layer are composed of the porous body. Furthermore, since the poly (vinyl alcohol) -styrylpyridinium compound is a material having excellent hydrophilicity, the measurement object penetrating from the analyte adjustment layer is smoothly taken into the analyte sensing layer through the intermediate layer. Can be made. Therefore, since the contact opportunity of a measuring object and an enzyme increases, an enzyme reaction can be advanced smoothly.

  In the detection element of the present invention, when the average thickness of the analyte sensing layer is A [μm] and the average thickness of the intermediate layer is B [μm], 1.0 ≦ B / A ≦ 2.5 It is preferable to satisfy the following relationship.

  If B / A is less than the lower limit, the separation distance between the analyte sensing layer and the analyte adjustment layer becomes too small, and depending on the type of enzyme contained in the analyte sensing layer, an intermediate layer may be provided. There is a possibility that the effect to be obtained, that is, the effect of suppressing or preventing the decrease in the activity of the enzyme and thus the inactivation of the enzyme may not be sufficiently obtained. In addition, when B / A exceeds the upper limit, the separation distance between the analyte sensing layer and the analyte adjustment layer becomes too large, the penetration of the measurement target into the analyte detection layer is not performed, and the detection sensitivity of the measurement target is not achieved. There is a risk of lowering.

  In the detection element of the present invention, the average thickness A of the intermediate layer is preferably 0.1 μm or more and 25 μm or less.

  Thereby, it is possible to detect the measurement object with excellent detection sensitivity while accurately suppressing or preventing a decrease in the activity of the enzyme.

In the detection element of the present invention, the enzyme is preferably glucose oxidase.
According to glucose oxidase, since the enzyme reaction can proceed with excellent activity, hydrogen peroxide can be reliably generated from glucose in the presence of O ₂ and H ₂ O.

  In the detection element of the present invention, it is preferable that the analyte adjustment layer has a crosslinked structure including a urethane bond or a urea bond, and has an isocyanate group remaining when the urethane bond is formed.

  By applying the detection element of the present invention to a detection element having an analyte adjustment layer having such a configuration, interposing an intermediate layer between the analyte sensing layer and the analyte adjustment layer, and separating them from each other Since the contact opportunity between the isocyanate group and the enzyme can be reduced, it is possible to accurately suppress or prevent the enzyme activity from decreasing.

  In the detection element of the present invention, the average thickness of the analyte adjusting layer is preferably 0.1 μm or more and 10 μm or less.

  As a result, the measurement target can be smoothly permeated into the analyte adjustment layer, and the enzyme retained in the analyte sensing layer can be accurately suppressed or prevented from leaking to the interstitial fluid side. it can.

The analysis device of the present invention displays the detection element of the present invention, an arithmetic device provided with a processing circuit for analyzing the current value obtained by the detection element, and a measurement value obtained by calculating with the arithmetic device And a display unit to be provided.
Such an analyzer is excellent in reliability.

The insulin supply device of the present invention includes a detection element of the present invention, an arithmetic device provided with a processing circuit for analyzing a current value obtained by the detection element, and a measurement value obtained by calculating by the arithmetic device. And a supply unit for supplying insulin to the subcutaneous tissue.
Such an insulin supply device is excellent in reliability.

It is a perspective view showing typically an embodiment of an analysis device of the present invention, and shows a state where a desorption part with which a detection element which an analysis device has is equipped is attached to a main part. It is a perspective view showing typically an embodiment of an analysis device of the present invention, and shows a state where a desorption part with which a detection element which an analysis device has is detached from a main part. It is a side view which shows the state which mounted | wore the skin with the detection element which embodiment of the analyzer of this invention has. It is a longitudinal cross-sectional view which expands and shows the cannula with which the detection element shown in FIG. 3 is provided. It is a top view which shows the detection part with which the detection element shown in FIG. 3 is provided. It is a longitudinal cross-sectional view which shows the detection part with which the detection element shown in FIG. 3 is provided. It is a flowchart which shows the method of measuring a glucose level using the analyzer of this invention. It is a perspective view which shows typically the state with which the detection element of this invention was mounted | worn with the insulin supply apparatus. It is a longitudinal cross-sectional view which shows the detection part with which the detection element produced in each Example is provided.

  Hereinafter, a detection element, an analysis device, and an insulin supply device of the present invention will be described in detail based on embodiments shown in the accompanying drawings.

  In the present embodiment, the case where the analyzer of the present invention is applied to a continuous glucose monitor (CGM) device that continuously monitors the glucose concentration in the interstitial fluid over a long period will be described as an example.

<Analyzer>
First, an analysis apparatus (analysis apparatus of the present invention) equipped with the detection element of the present invention will be described.

  FIG. 1 is a perspective view schematically showing an embodiment of the analyzer of the present invention, showing a state in which a detachable part included in a detection element included in the analyzer is mounted on a main body, and FIG. 2 is an analysis of the present invention. FIG. 3 is a perspective view schematically showing an embodiment of the apparatus, showing a state in which a detachable part included in a detection element included in the analyzer is detached from the main body, and FIG. 3 is a detection that the embodiment of the analyzer of the present invention has FIG. 4 is an enlarged longitudinal sectional view showing a cannula provided in the detection element shown in FIG. 3, and FIG. 5 shows a detection unit provided in the detection element shown in FIG. FIG. 6 is a plan view showing a detection unit included in the detection element shown in FIG. In the following description, the upper side in FIGS. 3, 4, and 6 is referred to as “upper” and the lower side is referred to as “lower”. Further, the front side of the paper surface in FIG.

  The analysis apparatus 101 shown in FIGS. 1 and 2 is used by connecting the detection element 100, and the detection element 100 and a circuit 400 for obtaining a current value based on the glucose concentration in the detection element 100 are obtained. A display unit 155 having a processing circuit 200 for analyzing the measured current value, a display unit 155 having a monitor 151 for displaying a measurement value obtained by calculation by the calculation unit 210, and a detection element 100 are mounted on the display unit 155. A connector 131 to be connected (connection) and a wiring 132 for connecting the detection element 100 and the connector 131 are provided.

  As shown in FIGS. 1 to 4, the detection element 100 is detachable from the main body 110 including the cannula 111 inserted into the subcutaneous tissue 502 and the main body 110, and is detachable including the needle 121 on the distal end side. Part 120.

  The detachable portion 120 has a grip portion 122 located on the proximal end side and a needle portion 121 located on the distal end side, and the needle portion 121 is inserted into the through-hole 112 provided in the body portion 110 so that the main body portion is inserted. 110 (see FIG. 1), and can be detached by pulling out the needle 121 in a state where the grip 122 is gripped (see FIG. 2).

  The needle portion (insertion needle) 121 has a sharp tip, and the overall shape is a semi-cylindrical shape. When the detachable part 120 is attached to the main body part 110, it penetrates the through hole 112 and protrudes from the lower surface of the main body part 110, thereby enclosing a part of the side surface of the cannula 111 as shown in FIG. , Configured to mate with the cannula 111. Therefore, when attaching the main body 110 to the epidermis 501, the needle part 121 pierces the epidermis 501. At this time, the cannula 111 surrounded by the needle part 121 also pierces the epidermis 501 together with the needle part 121. It is inserted into the subcutaneous tissue 502. Then, after inserting the needle part 121 with the cannula 111 into the subcutaneous tissue 502, the cannula 111 is inserted into the subcutaneous tissue 502 by grasping the grip part 122 and detaching the detachable part 120 from the main body part 110 ( The needle 121 can be removed (pulled out) from the subcutaneous tissue 502 in the state of being left. In this manner, the detachable portion 120 (needle portion 121) is used for placing the cannula 111 protruding from the main body 110 percutaneously into the subcutaneous tissue 502 when the main body 110 is attached to the epidermis 501. Used as a guide member.

  The main body 110 has a dome shape as a whole, and includes a cannula 111 protruding from the lower surface. The main body 110 includes an adhesive layer on the lower surface, and is attached (fixed) by bringing the lower surface into contact with the skin 501. At this time, the cannula 111 is placed in the subcutaneous tissue 502 by the guidance of the needle 121 described above.

  The cannula 111 has a cylindrical shape as a whole, and includes a hollow portion 114 constituted by a communication hole (through hole) communicating from the base end to the tip end, and a window portion 113 that opens the hollow portion 114 to the outside of the cannula 111. And have.

  The hollow portion 114 is provided with a detection unit 300 included in the main body 110. The interstitial fluid contained by moving from the blood vessel 503 to the subcutaneous tissue 502 comes into contact with the detection unit 300 through the window 113. Therefore, glucose in the interstitial fluid is detected by the detection unit 300. By attaching the main body 110 to the epidermis 501, the cannula 111 can be placed in the subcutaneous tissue 502 over a long period of time, so that glucose in the interstitial fluid can be detected continuously. That is, the main body 110 (detection element 100) is used for a continuous glucose monitoring system (CGMS) that continuously observes the glucose level in the interstitial fluid.

  Here, the detection of glucose by the detection unit 300 is performed using the following principle.

  That is, when glucose and oxygen are present in the vicinity of an enzyme in the presence of an enzyme (for example, glucose oxidase), gluconic acid and hydrogen peroxide are generated as shown in the following formula (1) by an enzyme reaction. Then, the amount of hydrogen peroxide is quantified by measuring the amount of current generated by applying a voltage (for example, 600 mV) to the generated hydrogen peroxide and electrolyzing it between the working electrode and the counter electrode. Can be Therefore, the amount of glucose can be calculated based on the quantified amount of hydrogen peroxide.

  In the electrolysis of hydrogen peroxide, protons, oxygen and electrons are generated on the working electrode (anode) side by electrolysis of hydrogen peroxide as shown in the following formula (2), and the counter electrode (cathode) On the) side, hydroxide ions are generated by the reaction of electrons supplied from the working electrode with oxygen and water present in the vicinity of the electrode, as shown in the following formula (3).

Enzyme reaction: Glucose + O ₂ + H ₂ O → Gluconic acid + H ₂ O ₂ (1)
Working electrode: H ₂ O ₂ → O ₂ + 2H ⁺ + 2e ⁻ (2)
Counter electrode: O ₂ + H ₂ O + 4e ⁻ → 4OH ⁻ (3)

Hereinafter, the detection part 300 which detects glucose using this principle is explained in full detail.
As shown in FIGS. 5 and 6, the detection unit 300 includes a substrate 301, a conductive layer (electrode) 315, and a sensing layer (enzyme layer) 320.

  The substrate (base substrate) 301 supports each unit (in this embodiment, the conductive layer 315 and the sensing layer 320) constituting the detection unit 300.

  As a constituent material of the substrate 301, various materials can be used without particular limitation as long as they are stable without chemically reacting with air, water, body fluid, blood, and interstitial fluid. Specifically, an inorganic material such as glass, SUS, amorphous polyarylate (PAR), polysulfone (PSF), polyethersulfone (PES), polyphenylene sulfide (PPS). , Polyetheretherketone (PEEK: Polyether ether ketone), Polyimide (PI: Polyimide), Polyetherimide (PEI: Polyetherimide), Fluorocarbon Polymer (Fluorocarbon Polymer), Nylon, Amide Polyester such as polyamide (PA) and polyethylene terephthalate (PET) The resin material of these etc. is mentioned, Among these, it can be used combining 1 type (s) or 2 or more types.

  The conductive layer (electrode layer) 315 detects electrons generated by electrolyzing hydrogen peroxide generated in the sensing layer 320 described later, and measures the detected electrons as a current amount.

  The conductive layer 315 is formed on the substrate 301 and includes a working electrode 311, a counter electrode 312, a reference electrode 313, and a wiring 314.

  Each of the electrodes 311, 312, and 313 is electrically connected to the circuit 400 and the processing circuit 200 via the wiring 314, the wiring 132, and the connector 131 independently. Thereby, the current value measured by each electrode 311, 312 (conductive layer 315) is transmitted to the circuit 400 and the processing circuit 200 included in the display unit 155 via the wirings 314 and 132, and the arithmetic device including the processing circuit 200 By the analysis of 210, the glucose value in the interstitial fluid is calculated as a measured value. And this measured value (glucose value) is displayed on the monitor 151, and a glucose value is continuously notified to a wearer.

  Further, the constituent material of each of the electrodes 311, 312 and 313 is not particularly limited as long as it can be used as an enzyme electrode, and for example, a metal material such as gold, silver, platinum or an alloy containing these, respectively. And metal oxide materials such as ITO and carbon materials such as carbon (graphite).

  The electrodes 311, 312, 313 can be formed by sputtering, plating, or vacuum heating evaporation when the electrodes 311, 312, 313 are made of platinum, gold, or an alloy thereof. . Further, when each of the electrodes 311, 312, and 313 is made of carbon graphite, it can be realized by mixing the carbon graphite with a binder dissolved in an appropriate solvent and applying it.

  The sensing layer 320 is formed by being laminated on the conductive layer 315, that is, is formed so as to cover the working electrode 311, the counter electrode 312, and the reference electrode 313, and from the interstitial liquid that is in contact with the upper surface of the sensing layer 320. Hydrogen peroxide is generated from the permeated glucose by an enzyme reaction, and this hydrogen peroxide is supplied to the conductive layer 315. The glucose is detected by an enzyme reaction that generates hydrogen peroxide from glucose. is there.

  In the present invention, the sensing layer 320 includes an analyte sensing layer 321, an intermediate layer 322, and an analyte adjustment layer 323, which are laminated in this order from the conductive layer 315 side. It consists of Hereinafter, each of these layers will be described.

  The analyte sensing layer (enzyme layer) 321 is formed so as to cover the working electrode 311, the counter electrode 312 and the reference electrode 313, and is subjected to an enzymatic reaction from glucose permeated through the intermediate layer 322 and the analyte adjustment layer 323. It generates hydrogen oxide. Then, the generated hydrogen peroxide is supplied to the conductive layer 315.

The analyte sensing layer 321 is a layer that includes an enzyme. As described above, the detection element 100 detects (senses) glucose (analyte) in the interstitial fluid. As such, glucose oxidase (GOD) is preferably used. According to glucose oxidase, since the enzyme reaction represented by the above formula (1) can be advanced with excellent activity, hydrogen peroxide is reliably generated from glucose in the presence of O ₂ and H ₂ O. Can be made.

  In addition to the enzyme, the analyte sensing layer 321 includes a resin material as another component for the purpose of retaining the enzyme in the analyte sensing layer 321.

  The resin material is not particularly limited. For example, methyl cellulose (MC), acetyl cellulose (cellulose acetate), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), and polyvinyl alcohol-polyvinyl acetate copolymer (PVA-PVAc). Etc. are preferably used, and one or more of these can be used in combination. By using these resin materials, the enzyme can be held in the analyte sensing layer 321 and the enzyme can be prevented from moving out of the analyte sensing layer 321.

  Further, the analyte sensing layer 321 may contain albumin, a phosphate buffer, etc., in addition to the binder or curing agent.

  Examples of the binder or curing agent include materials having two or more functional groups such as aldehyde and isocyanate in the molecule. By including such a binder or curing agent in the analyte sensing layer 321, the analyte sensing layer 321 can retain the enzyme in the analyte sensing layer 321 with an excellent retention rate.

  Specific examples of the binder and curing agent include glutaraldehyde, toluene diisocyanate, isophorone diisocyanate, and the like, and one or more of these can be used in combination. Moreover, as a binder and a hardening | curing agent using UV curability, a poly (vinyl alcohol) -styryl pyridinium compound (PVA-SbQ) etc. are mentioned, for example.

  The analyte sensing layer 321 containing such a binder or curing agent includes a binder or a curing agent and a functional group capable of binding to a functional group included in these, specifically a hydroxyl group, an amino group, an epoxy group, or the like. It can be obtained by curing a resin composition in which a resin material at the end and an enzyme are mixed.

Furthermore, when using a poly (vinyl alcohol) -styrylpyridinium compound (PVA-SbQ) as a binder or curing agent using UV curability, the addition of a resin material having a functional group at the end is omitted. The analyte sensing layer 321 can also be constituted by a cured product obtained by curing a resin composition containing PVA-SbQ and an enzyme. In this case, the analyte sensing layer 321 smoothly takes in the interstitial fluid penetrating from the intermediate layer 322 side into the analyte sensing layer 321 while the enzyme is held in the porous body composed of PVA-SbQ. since the can, it is possible to increase the chance of contact between glucose and enzymes involved in the interstitial fluid, the enzyme reaction represented by the formula (1) can proceed smoothly, O ₂ and H ₂ Hydrogen peroxide can be reliably generated from glucose in the presence of O. In addition, since the enzyme can be firmly held in the porous body composed of PVA-SbQ, it is possible to accurately suppress or prevent the enzyme from moving to the intermediate layer 322 side.

  Examples of albumin include human albumin and bovine albumin. By containing albumin, the enzyme can be protected and stabilized.

  The average thickness of the analyte sensing layer 321 is not particularly limited, but is preferably about 0.1 μm to 10.0 μm, and more preferably about 0.5 μm to 5.0 μm. Accordingly, hydrogen peroxide can be generated smoothly by an enzymatic reaction between glucose permeated from the intermediate layer 322 side and an enzyme held in the analyte sensing layer 321, and the generated hydrogen peroxide can be smoothly conducted. Layer 315 can be provided.

  The analyte adjustment layer 323 is stacked on the upper side of the analyte sensing layer 321 via the intermediate layer 322, and the analyte sensing layer 321 is measured by the analyte adjustment layer 323 (interstitial fluid or blood). In addition, the function of allowing glucose (analyte) to permeate and smoothly permeate into the analyte sensing layer 321 via the intermediate layer 322 while suppressing or preventing contact with the electrolyte. That is, it has a function of adjusting the transmission to the analyte sensing layer 321. Furthermore, it also functions as a blocking layer that prevents the enzyme retained in the analyte sensing layer 321 from leaking to the interstitial fluid side.

  Moreover, it is preferable that the analyte adjustment layer 323 having such a function can permeate (permeate) oxygen more than glucose. Thereby, in the detection of glucose using the above formulas (1) to (3), it is possible to accurately suppress or prevent the glucose measurement value from apparently decreasing due to the lack of oxygen. be able to. That is, the detection accuracy of the glucose measurement value is improved.

  Such an analyte adjustment layer 323 is not particularly limited. For example, a polyethylene glycol (PEG), a polypropylene glycol (PPG), or a 4-hydroxy acrylate is a polymer having a crosslinking agent such as an isocyanate compound and a terminal hydroxyl group. Particularly preferred are those in which a cross-linked structure is constructed by forming a urethane bond using butyl or the like alone or mixed. Thereby, the function as the analyte adjustment layer 323 mentioned above can be exhibited more notably.

  In addition, it is possible to use those composed of aminopropylpolysiloxane or the like in which urea resin is formed by using isocyanate and amino group, and further composed of siloxane resin such as polydimethylsiloxane. A thing can also be used.

  The average thickness of the analyte adjusting layer 323 is not particularly limited, but is preferably about 0.1 μm to 10.0 μm, and more preferably about 0.5 μm to 5.0 μm. As a result, glucose can be smoothly permeated into the analyte adjustment layer 323, and the enzyme retained in the analyte sensing layer 321 can be accurately suppressed or prevented from leaking to the interstitial fluid side. Can do.

  The intermediate layer (protective layer) 322 is a layer that does not contain an enzyme, is laminated on the analyte sensing layer 321, and is positioned between the analyte sensing layer 321 and the analyte adjustment layer 323. 321 and the analyte adjustment layer 323 are separated from each other.

  Accordingly, the conductive layer 315, the analyte sensing layer 321, the intermediate layer 322, and the analyte adjustment layer 323 are stacked in this order in the thickness direction.

  Here, the analyte sensing layer 321 described above exhibits a function of smoothly generating hydrogen peroxide by an enzyme reaction between glucose permeated from the intermediate layer 322 side and an enzyme held in the analyte sensing layer 321. In order to exhibit the function of smoothly supplying the generated hydrogen peroxide to the conductive layer 315, the average thickness (film thickness) is set to be relatively thin, specifically, preferably 0.1 μm. It is set to about 10 μm or less. When the cannula 111 is inserted into the subcutaneous tissue 502 or the interstitial fluid penetrates into the sensing layer 320 (analyte sensing layer 321), the analyte sensing layer 321 having such a thin film thickness is used. There is a problem that physical damage occurs because an external load is applied.

  On the other hand, in the present invention, an intermediate layer 322 is provided between the analyte sensing layer 321 and the analyte adjustment layer 323, and the analyte sensing layer 321 is laminated on the analyte sensing layer 321. It functions as a protective layer that covers and reinforces the layer 321. Therefore, even if an external load is applied to the analyte sensing layer 321, it is possible to accurately suppress or prevent physical damage from occurring in the analyte sensing layer 321.

  Further, since the intermediate layer 322 is located between the analyte sensing layer 321 and the analyte adjustment layer 323, the intermediate layer 322 serves as a barrier layer that prevents the enzyme from moving to the analyte adjustment layer 323 side. It is also possible to demonstrate the function.

  The constituent material of the intermediate layer 322 is not particularly limited, but a material that exhibits UV curable properties and biocompatibility, has excellent hydrophilicity, and can smoothly pass glucose, is specifically used. For example, poly (vinyl alcohol) -styrylpyridinium compound (PVA-SbQ), poly (2-hydroxyethyl methacrylate) (PHEMA / PAA-HEMA), 2-methacryloyloxyethyl phosphorylcholine (MPC), poly N isopropylacrylamide-modified polyvinyl Alcohol (PNIPAAm-PVA) etc. are mentioned, Among these, it can use combining 1 type (s) or 2 or more types.

  Such an intermediate layer 322 preferably does not contain an enzyme, and further contains the same main component (that is, the above-mentioned other components) as the analyte sensing layer 321 as a constituent material. Thereby, the interface between the intermediate layer 322 and the analyte sensing layer 321 can be made uniform. Therefore, the glucose that has permeated from the analyte adjustment layer 323 can be supplied from the intermediate layer 322 to the analyte sensing layer 321 without the interface between the intermediate layer 322 and the analyte sensing layer 321 becoming a barrier. Hydrogen peroxide can be generated smoothly by an enzyme reaction between the glucose and the enzyme held in the analyte sensing layer 321.

  As a combination of the constituent materials of the intermediate layer 322 and the analyte sensing layer 321, specifically, for example, both of the constituent materials of the intermediate layer 322 and the analyte sensing layer 321 are poly (vinyl alcohol). ) -Styrylpyridinium compound (PVA-SbQ) is preferably contained as a main component. That is, the analyte sensing layer 321 includes an enzyme and PVA-SbQ, the intermediate layer 322 preferably does not include an enzyme, and includes PVA-SbQ, and the intermediate layer 322 further includes an enzyme. Preferably, the analyte sensing layer 321 has a structure in which an enzyme is held in a porous body composed of PVA-SbQ.

Thus, since the intermediate layer 322 and the analyte sensing layer 321 are both composed of a porous body, and PVA-SbQ is a material having excellent hydrophilicity, the interstitial liquid that permeates from the analyte adjustment layer 323. Can be smoothly incorporated into the analyte sensing layer 321 through the intermediate layer 322. Therefore, since the contact opportunity between the glucose contained in the interstitial fluid and the enzyme increases, the enzyme reaction represented by the formula (1) can be smoothly advanced, and the presence of O ₂ and H ₂ O Under, hydrogen peroxide can be reliably generated from glucose.

  In addition, since the enzyme can be firmly held in the porous body composed of PVA-SbQ, it is possible to accurately suppress or prevent the enzyme from moving to the intermediate layer 322 side.

  Furthermore, it is possible to accurately suppress or prevent the enzyme from being deactivated due to the analyte sensing layer 321 coming into contact with the intermediate layer 322 at the interface between the intermediate layer 322 and the analyte sensing layer 321. .

  Note that the intermediate layer 322 may contain albumin or the like in addition to the constituent materials described above. Examples of albumin include human albumin and bovine albumin. By containing albumin, the enzyme can be protected and stabilized at the upper interface (upper surface) of the analyte sensing layer 321.

  In addition, the intermediate layer 322 is positioned between the analyte sensing layer 321 and the analyte adjustment layer 323, and thus functions as a spacer that separates them.

  Here, the analyte adjustment layer 323 is particularly preferably formed of a crosslinked structure including a urethane bond. In this case, the analyte adjustment layer 323 has an isocyanate group remaining upon formation of the urethane bond. Is included. Since such an isocyanate group has excellent reactivity, the isocyanate group is included in the analyte sensing layer 321 when the analyte sensing layer 321 and the analyte adjustment layer 323 are joined without the intermediate layer 322 interposed therebetween. Due to the contact with the enzyme, the activity of the enzyme is lowered and the enzyme is deactivated, and the detection (quantitative) sensitivity of glucose in the interstitial fluid becomes defective.

  In contrast, by interposing the intermediate layer 322 between the analyte sensing layer 321 and the analyte adjustment layer 323 and separating them from each other, it is possible to reduce the chance of contact between the isocyanate group and the enzyme. Therefore, it is possible to accurately suppress or prevent a decrease in the activity of the enzyme. As a result, the detection of glucose is performed without causing a problem in the sensitivity (quantification) of glucose in the interstitial fluid.

  As described above, when the intermediate layer 322 functions as a spacer, when the average thickness of the analyte sensing layer 321 is A [μm] and the average thickness of the intermediate layer 322 is B [μm] 1.0 ≦ B / A ≦ 2.5 is satisfied, and it is more preferable that the relationship 1.0 ≦ B / A ≦ 2.0 is satisfied. When B / A is less than the lower limit, the separation distance between the analyte sensing layer 321 and the analyte adjustment layer 323 becomes too small, and depending on the type of enzyme contained in the analyte sensing layer 321, the intermediate layer 322. There is a possibility that the effect obtained by providing the above, that is, the effect of suppressing or preventing the decrease in the activity of the enzyme and thus the inactivation of the enzyme may not be sufficiently obtained. When B / A exceeds the upper limit, the separation distance between the analyte sensing layer 321 and the analyte adjustment layer 323 becomes too large, and glucose permeation into the analyte sensing layer 321 is not sufficiently performed. There is a risk of lowering the detection sensitivity.

  Specifically, the average thickness A of the intermediate layer 322 is preferably about 0.1 μm to 25 μm, and more preferably about 0.5 μm to 12 μm. This makes it possible to detect the glucose concentration with excellent detection sensitivity while accurately suppressing or preventing a decrease in enzyme activity.

  The sensing layer 320 may include other layers in addition to the analyte sensing layer 321, the intermediate layer 322, and the analyte adjustment layer 323 described above. Examples of such a layer include: An example is a noise removal layer laminated on the lower side of the analyte sensing layer 321.

  This noise removal layer is caused by a compound such as acetaminophen, ascorbic acid, and uric acid, which may be included in the interstitial fluid, passing through the analyte sensing layer 321 and reaching the conductive layer 315. And a function of preventing a decrease in the detection sensitivity of the glucose measurement value.

  The constituent material of the noise removal layer is not particularly limited as long as it can exhibit the above functions. For example, methyl cellulose (MC), acetyl cellulose (cellulose acetate), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) ), Polyvinyl alcohol-polyvinyl acetate copolymer (PVA-PVAc), hydroxyethyl methacrylate, poly (2-hydroxyethyl methacrylate) (HEMA), and the like. They can be used in combination.

  In order to insolubilize the noise removal layer, an isocyanate compound may be added to the noise removal layer so that isocyanate can be used as a functional group, or poly (vinyl alcohol) may be used so that UV curability can be utilized. ) -Styrylpyridinium compound (PVA-SbQ) or the like may be added to the noise removal layer.

  Furthermore, albumin may be contained in the noise removal layer. This can protect the lower boundary surface (lower surface) of the analyte sensing layer located on the noise removal layer.

  In the present embodiment, the detection unit 300 has been described with respect to the case where the working electrode 311, the counter electrode 312, the reference electrode 313, and the wiring 314 included in the conductive layer 315 are entirely covered with the analyte sensing layer 321. The analyte sensing layer 321 may be selectively formed on the working electrode 311 and the counter electrode 312, or the analyte sensing layer 321 may be selectively formed on the working electrode 311. Good.

  Further, as shown in FIGS. 1 and 2, the display unit 155 includes a circuit 400 disposed therein and electrically connected via wirings 314 and 132 for driving the detection unit 300. Yes.

  The circuit 400 is electrically connected to a working electrode 311, a reference electrode 313, and a counter electrode 312 that are included in the detection unit 300.

  For example, a voltage difference of 600 mV is maintained between the working electrode 311 and the reference electrode 313, and this difference becomes an applied voltage to the detection unit 300. As a result, hydrogen peroxide contained in the sensing layer 320 is electrolyzed. By doing so, electrons are generated. Then, the electrons are measured as a current value based on the glucose concentration between the working electrode 311 and the counter electrode 312, and the current value is analyzed by the arithmetic device 210 included in the processing circuit 200, thereby obtaining a glucose value. Is calculated as a measured value, and this measured value is displayed on the monitor 151.

<Measurement method>
In addition, the measurement of the glucose value in the interstitial fluid using the above-described analyzer 101 is specifically performed as follows, for example.

  FIG. 7 is a flowchart showing a method for measuring a glucose level using the analyzer of the present invention.

  [1] First, the cannula 111 is inserted into the subcutaneous tissue 502, and the detection unit 300 (sensing layer 320) is brought into contact with the interstitial fluid to be stabilized (S1).

  [2] Next, a constant voltage is applied between the working electrode 311 and the reference electrode 313 at a predetermined length. Thus, hydrogen peroxide generated in the vicinity of the working electrode 311 of the sensing layer 320 at the time of stabilization is electrolyzed as shown in the above equation (2), so that the vicinity of the working electrode 311 of the sensing layer 320 is initialized ( S2).

  [3] Next, after a certain time interval, a constant voltage is applied between the working electrode 311 and the reference electrode 313 at a predetermined length. As a result, hydrogen peroxide generated in the vicinity of the working electrode 311 of the sensing layer 320 is electrolyzed as in the above formula (2), and as a result, the generated electrons flow between the working electrode 311 and the counter electrode 312. The glucose value in the interstitial fluid is determined by measuring the measured current value (S3).

  In addition, although this process [3] may be performed once, since glucose value is averaged by repeating process [3] and calculating | requiring the average value of the glucose value measured in the meantime, , The glucose level can be determined with higher reliability.

By repeatedly performing the above steps [1] to [3] at a predetermined interval,
The glucose level (glucose concentration) in the interstitial fluid can be continuously measured.

<Insulin supply device>
In addition to being mounted on the analyzer as described above, the detection element of the present invention is mounted on, for example, an insulin supply device (insulin supply device of the present invention).

  FIG. 8 is a perspective view schematically showing a state in which the detection element of the present invention is mounted on the insulin supply apparatus.

  An insulin supply device 171 shown in FIG. 8 is used by connecting the detection element 100, and includes a detection element 100 and an arithmetic device 210 including a processing circuit 200 that analyzes a current value obtained by the detection element 100. And a supply unit 175 including a needle unit 172 that supplies (administers) insulin to the subcutaneous tissue 502 based on a measurement value obtained by calculation by the calculation device 210, and a detection element 100 is attached (connected) to the supply unit 175. And a wiring 132 that connects the processing circuit 200 and the connector 131. In such an insulin supply device 171, the current value flowing between the working electrode 311 and the counter electrode 312 is transmitted to the processing circuit 200 via the circuit 400 and the wiring 132 provided in the main body 110, and the processing circuit 200 The glucose value (glucose concentration) in the interstitial fluid is calculated as a measured value by the analysis of the arithmetic device 210 including the above. Then, based on this measured value (glucose value), that is, when the measured value is higher than the set concentration, the insulin supply device 171 is activated and insulin is automatically supplied to the wearer via the needle portion 172. Be administered.

  As described above, the detection element, the analysis device, and the insulin supply device of the present invention have been described based on the illustrated embodiment, but the present invention is not limited to this.

  For example, the configuration of each unit in the detection element, analysis device, and insulin supply device of the present invention can be replaced with any configuration having the same function. In addition, any other component may be added to the present invention. Further, the present invention may be a combination of any two or more configurations (features) of the analysis device and the insulin supply device.

In addition to inserting the cannula into the subcutaneous tissue, the cannula may be inserted into the skin.
Furthermore, in the analyzer and the insulin supply device, the current value measured by the detection element may be transmitted to the processing circuit without going through the wiring. For example, the current value can be transmitted wirelessly via the communication means. You may make it transmit to a processing circuit.

  Further, in the analysis device, the detection element and the display unit are not limited to being connected via a wiring, and these may be integrally formed. In the insulin supply device, the detection element And the supply unit are not limited to those connected via wiring, and may be integrally formed.

Next, specific examples of the present invention will be described.
1. Production of detection element (Example 1)
<1> First, a transparent glass substrate having an average thickness of 0.5 mm was prepared as the substrate 301.

  <2> Next, a patterned platinum film having an average thickness of 200 nm was formed as a conductive layer (electrode layer) 315 including a working electrode 311, a counter electrode 312 and a reference electrode 313 on a glass substrate by a mask sputtering method.

  <3> Next, a bank having an average height of 8 μm is formed on the platinum film with a photoresist using an acrylic material, and an opening that contacts the liquid to be measured (blood, interstitial fluid) is opened, thereby forming a partition wall Layer 331 was formed.

  <4> Next, the substrate on which the conductive ITO film, the platinum film, and the partition wall layer were laminated was immersed in acetone and 2-propanol in this order, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment and argon plasma treatment. Each of these plasma treatments was performed at a plasma power of 100 W, a gas flow rate of 20 sccm, and a treatment time of 5 seconds with the substrate heated to 70 to 90 ° C.

  <5> Next, on the platinum electrode of the reference electrode 313, an ink containing silver-silver chloride particles is filled in an amount such that the film thickness becomes 3 μm after being dried by an inkjet method, and dried in an oven at 120 ° C. A silver-silver chloride film was formed.

  <6> Next, 5 mg of GOD (glucose oxidase activity 150 U / mg) was dissolved in 6.1 g of ultrapure water to obtain a GOD solution. Further, 1.22 g of the obtained GOD solution was weighed, and PVA-SbQ (13.3). The material for forming an analyte sensing layer was prepared by mixing with 1.0 g of a% aqueous solution.

  Then, the analyte sensing layer forming material is dropped on the entire surface of the working electrode 311, the counter electrode 312 and the reference electrode 313 with a syringe and applied using a spin coating method under conditions of 1000 rpm to 300 sec. After forming a liquid film of .8 μm, the film was naturally dried for 5 minutes to obtain a thin film. Thereafter, the analyte sensing layer 321 was formed by irradiating ultraviolet rays having a wavelength of 365 nm for 5 minutes to form an insolubilized film (cured film).

  <7> Next, an intermediate layer forming material was prepared by mixing 1.0 g of PVA-SbQ (13.3% aqueous solution) and 2.33 g of ultrapure water.

  After this intermediate layer forming material is deposited on the entire surface of the analyte sensing layer with a syringe, the intermediate layer forming material is applied using a spin coating method under the condition of 1000 rpm-300 sec. The film was naturally dried to obtain a thin film having a thickness of 0.2 μm. Thereafter, an intermediate layer 322 was formed by irradiating ultraviolet rays having a wavelength of 365 nm for 5 minutes to form an insolubilized film (cured film).

  <8> Next, 0.45 g of PPG (polypropylene glycol) triol type (300), 0.5 g of toluene, 0.5 g of isophorone diisocyanate, and 1 drop of diazabicycloundecene (DBU) are mixed with stirring. Then, an analyte adjusting layer forming material was prepared.

Then, this analyte adjusting layer forming material is applied onto the entire surface of the intermediate layer by dropping the analyte preparing layer forming material with a syringe under the condition of 1000 rpm-300 sec using a spin coating method, and then left for 24 hours. By forming urethane, an analyte adjusting layer 323 having a film thickness of 6.0 μm and having a crosslinked structure including a urethane bond and having an isocyanate group remaining during the formation of the urethane bond was formed.
Through the above steps, the detection unit 300 of Example 1 having the configuration shown in FIG. 9 was manufactured.

(Example 2)
A detection unit 300 of Example 2 having the configuration of FIG. 9 was manufactured in the same manner as in Example 1 except that the process <7> was changed to the process <7A> shown below.

  <7A> An intermediate layer forming material was prepared by mixing 1.0 g of PVA-SbQ (13.3% aqueous solution) and 1.22 g of ultrapure water.

  After forming the liquid film by applying the intermediate layer forming material to the entire surface of the analyte sensing layer with a syringe and applying the intermediate layer forming material using a spin coating method at 3000 rpm to 300 sec. The film was naturally dried to obtain a thin film having a thickness of 0.4 μm. Thereafter, an intermediate layer 322 was formed by irradiating ultraviolet rays having a wavelength of 365 nm for 5 minutes to form an insolubilized film (cured film).

(Example 3)
A detection unit 300 of Example 3 having the configuration of FIG. 9 was manufactured in the same manner as in Example 1 except that the process <7> was changed to the process <7B> shown below.

  <7B> An intermediate layer forming material was prepared by mixing 1.0 g of PVA-SbQ (13.3% aqueous solution) and 1.22 g of ultrapure water.

  After this intermediate layer forming material is deposited on the entire surface of the analyte sensing layer with a syringe, the intermediate layer forming material is applied using a spin coating method under the condition of 1000 rpm-300 sec. A thin film having a thickness of 0.8 μm was obtained by natural drying. Thereafter, an intermediate layer 322 was formed by irradiating ultraviolet rays having a wavelength of 365 nm for 5 minutes to form an insolubilized film (cured film).

(Comparative Example 1)
A detection unit 300 of Comparative Example 1 was manufactured in the same manner as in Example 1 except that Step <7> was omitted.

2. Evaluation 2-1. Measurement of glucose sensitivity First, a solution prepared in phosphate physiological saline so that the glucose concentration was 1 mg / dL was prepared as a standard solution.
And this standard solution was heated so that it might become fixed at 35 degreeC.

  Next, the detection unit 300 of each of the examples and the comparative examples is immersed in a heated standard solution, so that the analyte sensing layer 321, the intermediate layer 322, and the position at positions corresponding to the working electrode, the counter electrode, and the reference electrode The analyte adjustment layer 323 was impregnated with a standard solution.

  Next, with respect to the detection units 300 of each Example and Comparative Example impregnated with the standard solution, when a voltage was applied so that the voltage between the reference electrode and the working electrode was 0.6 V, the working electrode was paired with the working electrode. The current value flowing between the electrodes was measured.

2-2. Evaluation of linearity of current value First, prepared as standard solutions were prepared in phosphate saline so that the glucose concentration was 1 mg / dL, 10 mg / dL, 30 mg / dL, 70 mg / dL and 100 mg / dL. did.
And each of these standard solutions was heated so that it might become fixed at 35 degreeC.

  Subsequently, the detection part 300 of each Example and Comparative Example is immersed in each heated standard solution, so that the analyte sensing layer 321 and the intermediate layer 322 are located at positions corresponding to the working electrode, the counter electrode, and the reference electrode. The analyte adjustment layer 323 was impregnated with the standard solution.

  Next, with respect to the detection units 300 of each Example and Comparative Example impregnated with each standard solution, when a voltage was applied so that the voltage between the reference electrode and the working electrode was 0.6 V, the working electrode and The value of current flowing between the counter electrode was measured.

  And linearity (R2) was calculated | required by the following formula (A) using the electric current value measured about each standard solution for every Example and the comparative example. In the calculation formula, x represents the glucose concentration contained in each standard solution, and y represents the current value measured with the standard solution corresponding to each glucose concentration.

  These results are shown in Table 1.

  As shown in Table 1, when the analyte adjustment layer 323 has a cross-linked structure containing a urethane bond and has an isocyanate group remaining upon formation of the urethane bond, the average of the analyte sensing layer B / A, which is the ratio of the thickness A [μm] and the average thickness B [μm] of the intermediate layer, is set to 1.0 or more, thereby suppressing the decrease in the activity of the enzyme and hence the deactivation of the enzyme. The results showed that it can be prevented and excellent glucose sensitivity and linearity are obtained.

  On the other hand, when B / A is less than 1.0, the enzyme activity is lowered and the enzyme is deactivated, and it cannot be said that sufficient glucose sensitivity and linearity are obtained. showed that.

  In Example 3 where B / A is 1.0, the magnitude of glucose sensitivity is 0.412 nA / mg.

Here, the sensitivity required for the sensor that senses the difference in glucose concentration ± 10 mg / dL requires an accuracy of 4 nA / mm ² when the glucose sensitivity is 0.4 nA / mg, and the glucose sensitivity is 0.2 nA. / when mg is, it is necessary to precision 2nA / mm ^2, further, when the glucose sensitivity is 0.1 nA / mg has been shown to be required for accuracy 1 nA / mm ^2.

Furthermore, 1 nA / mm ² or less of the current is to be counted as noise due to the influence of components other than the living body temperature change or glucose to as having excellent accuracy of the sensor is 1 nA / mm ² greater than the current, Preferably, a current of ² nA / mm ² or more is required.

  Therefore, the glucose sensitivity needs to exceed 0.1 nA / mg, preferably 0.2 nA / mg or more.

  Therefore, since it is presumed that the glucose sensitivity shows a correlation with the film thickness of the intermediate layer, in order to make the glucose sensitivity more than 0.1 nA / mg, preferably 0.2 nA / mg or more, B / The upper limit value of the film thickness of A was considered to be 2.5 or less, preferably 2.0 or less.

DESCRIPTION OF SYMBOLS 100 ... Detection element, 101 ... Analyzing apparatus, 110 ... Main body part, 111 ... Cannula, 112 ... Through-hole, 113 ... Window part, 114 ... Hollow part, 120 ... Detachable part, 121 ... Needle part, 122 ... Gripping part, 131 ... Connector, 132 ... Wiring, 151 ... Monitor, 155 ... Display unit, 171 ... Insulin supply device, 172 ... Needle unit, 175 ... Supply unit, 200 ... Processing circuit, 210 ... Calculation device, 300 ... Detection unit, 301 ... Substrate 311 ... Working electrode, 312 ... Counter electrode, 313 ... Reference electrode, 314 ... Wiring, 315 ... Conductive layer, 320 ... Sensing layer, 321 ... Analyte sensing layer, 322 ... Intermediate layer, 323 ... Analyte adjustment layer, 331 ... partition wall layer, 400 ... circuit, 501 ... epidermis, 502 ... subcutaneous tissue, 503 ... blood vessel

Claims (10)

A substrate,
A conductive layer formed on the substrate;
A sensing unit having a sensing layer formed on the conductive layer,
The sensing layer includes an analyte sensing layer that senses an analyte, an analyte conditioning layer that regulates the analyte, and an intermediate layer that separates the analyte sensing layer and the analyte conditioning layer;
The detection element, wherein the conductive layer, the analyte sensing layer, the intermediate layer, and the analyte adjustment layer are arranged in this order in the thickness direction. The analyte sensing layer is formed of an enzyme and other components,
The detection element according to claim 1, wherein the intermediate layer is formed of only the other component.   The detection element according to claim 1, wherein the analyte sensing layer includes the enzyme and a poly (vinyl alcohol) -styrylpyridinium compound, and the intermediate layer includes a poly (vinyl alcohol) -styrylpyridinium compound.   The relationship of 1.0 ≦ B / A ≦ 2.5 is satisfied, where the average thickness of the analyte sensing layer is A [μm] and the average thickness of the intermediate layer is B [μm]. The detection element according to any one of 1 to 3.   The detection element according to claim 4, wherein an average thickness A of the intermediate layer is not less than 0.1 μm and not more than 25 μm.   The detection element according to claim 1, wherein the enzyme is glucose oxidase.   The detection element according to any one of claims 1 to 6, wherein the analyte adjustment layer has a crosslinked structure including a urethane bond, and has an isocyanate group remaining when the urethane bond is formed.   The detection element according to claim 1, wherein an average thickness of the analyte adjustment layer is 0.1 μm or more and 10 μm or less.   A detection device according to any one of claims 1 to 8, an arithmetic device including a processing circuit for analyzing a current value obtained by the detection device, and a measurement obtained by calculating with the arithmetic device An analysis apparatus comprising: a display unit that displays a value.   A detection device according to any one of claims 1 to 8, an arithmetic device including a processing circuit for analyzing a current value obtained by the detection device, and a measurement obtained by calculating with the arithmetic device An insulin supply apparatus comprising: a supply unit that supplies insulin to a subcutaneous tissue based on a value.

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