JP2011089781A - Biological sample detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means capable of judging the mounting posture of the sensor mountable on either one of the surface and rear of a detector body and capable of accurately detecting the substance to be detected in a biological sample. <P>SOLUTION: In a blood sugar measuring instrument 10, a biosensor 11 formed into a sheet shape having first and second surfaces 21 and 22 as the surface and the back and having a space 40 into which blood is introduced is provided to the connection part 13 of an instrument body 12 in either one of a first posture wherein the first surface 21 is a surface side and a second posture wherein the second surface 22 is a surface side in a detachable manner. A control part 55 judges whether the connection terminal 39 of a third electrode 27 electrically comes into contact with either one of a first terminal 61 and a second terminal 62 on the basis of the electrical state of the first terminal 61 or second terminal 62 to set either one of a first electrode 24 and a second electrode 26 to a positive electrode while setting the other one of them to a negative electrode to thereby measure a blood sugar level. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the present invention, the sensor having a sheet space in which the first surface and the second surface are front and back surfaces and having a sample space into which a biological sample is introduced is in the first posture or the second surface. The present invention relates to a biological sample detection device that can be attached to and detached from the connection portion of the device main body in any of the second postures on the front side.

  In recent years, the number of diabetic patients is increasing in each country. As a treatment for diabetes, for example, there is insulin therapy. Insulin is known as a drug that controls blood glucose levels and is administered to diabetic patients as a therapeutic agent for diabetes. The need to administer insulin is determined based on the blood glucose level of the diabetic patient. For this reason, it is important for a diabetic patient to grasp a blood glucose level. The blood glucose level is the glucose concentration in the blood. A simple blood glucose measuring device has been developed for the purpose of allowing a diabetic patient to easily measure his blood glucose level.

  As the blood glucose measurement device described above, one using a biosensor is known (Patent Documents 1 to 4). The biosensor has an electrode on which an enzyme that reacts with blood sugar is fixed. Glucose oxidase (hereinafter sometimes abbreviated as “GOD”) and glucose dehydrogenase (hereinafter sometimes abbreviated as “GDH”) are known as enzymes used for blood glucose level measurement. . In a biosensor, an electrode on which an enzyme is immobilized is called a working electrode, and an electrode that supplies electrons into a sample is called a counter electrode.

  When blood as a sample is introduced into the biosensor and GOD of the working electrode reacts with glucose in the blood, glucose is decomposed into gluconic acid and hydrogen peroxide, and the hydrogen peroxide is decomposed into water and electrons. The electrons generated in this way are transmitted to the working electrode. On the other hand, electrons are supplied from the counter electrode into the blood. In this way, a current flows between the working electrode and the counter electrode due to the reaction between GOD and glucose. Then, based on the flowing current value, the glucose concentration in the blood, that is, the blood glucose level is calculated. In addition, a substance that transmits electrons may be fixed to the working electrode. This material is referred to as an electron mediator. Examples of the electron mediator include organic compounds such as potassium ferricyanide, hexaammineruthenium and quinone derivatives, or organic-metal complexes.

  In the biosensor described above, the working electrode and the counter electrode are arranged to face each other in the thickness direction, and a space for introducing blood as a sample is formed between the working electrode and the counter electrode. The biosensor having such a configuration has a sheet-shaped outer shape. The biosensor is a so-called disposable that is disposable every time the blood glucose level is measured. Therefore, the biosensor is configured to be detachable from the apparatus main body, and the biosensor is replaced every time it is used.

  When diabetics change their biosensors themselves, it is necessary to check the front and back of the biosensor and attach it to the device body in the correct posture, but those who are unfamiliar with handling incorrectly attach the front and back to the device. There is also a risk. For such an erroneous operation, a biosensor has been devised in which the working electrode and the counter electrode have the same pattern and there is no difference in configuration between the front and back sides (Patent Document 5).

JP 2009-97877 A JP 2005-43280 A JP-A-2005-37335 JP 2002-107325 A JP 9-159642 A

  In order for the electrons generated by the enzyme reaction described above to be smoothly transmitted to the working electrode, electrons having a sufficient charge amount to the electrons transmitted to the working electrode may be supplied from the counter electrode into the blood. desirable. However, in the biosensor described in Patent Document 5, since the working electrode and the counter electrode have the same pattern, the area of the counter electrode cannot be increased with respect to the area of the working electrode, and electrons supplied from the counter electrode to the blood cannot be obtained. May be deficient.

  Further, in the biosensor described in Patent Document 5, it is necessary to apply a potential by distinguishing the working electrode and the counter electrode corresponding to the posture (front and back) of the biosensor mounted on the apparatus body. On the other hand, according to Patent Document 5, a voltage is applied to blood before measurement to determine whether or not current is flowing to the working electrode. However, in this method, glucose in blood and an enzyme at the working electrode are reacted before the original measurement, which may hinder accurate blood glucose measurement in the original measurement.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to determine in which posture a sensor that can be mounted on the apparatus main body is mounted on either the front or back side, and a living body. An object of the present invention is to provide means for accurately detecting a substance to be detected in a sample.

  (1) The present invention provides a sensor having a sheet shape in which a first surface and a second surface form front and back surfaces and a sample space into which a biological sample is introduced. The biological sample detection device is detachably provided to the connection portion of the device main body regardless of the second posture in which the second surface is the front side. In the sensor, a region in contact with a biological sample is exposed in the sample space, and a connection electrode of the first electrode is exposed only on either the first surface or the second surface; A contact area is exposed in the sample space, a second electrode whose connection terminal is exposed only on either the first surface or the second surface, and a region in contact with the biological sample is the sample space. And a third electrode whose connecting terminal is exposed only on one of the first surface and the second surface. The connection portion of the apparatus main body has a first terminal that comes into electrical contact with the connection terminal of the third electrode when the sensor is mounted as the first posture, and the sensor is mounted as the second posture. A second terminal that is in electrical contact with the connection terminal of the third electrode, and the connection terminal of the first electrode and the second terminal when the sensor is mounted in the first attitude or the second attitude. And a terminal group in selective and electrical contact with the connection terminal of the electrode. The apparatus main body determines whether the third electrode is in electrical contact with either the first terminal or the second terminal based on the electrical state of the first terminal or the second terminal. Sensor attitude determination means for determining whether the sensor is in the first attitude or the second attitude, and the first electrode and the second electrode via the terminal group based on the determination result of the sensor attitude determination means. Detecting means for electrically detecting a substance to be detected in a biological sample, with one of the electrodes as a positive electrode and the other as a negative electrode.

  Examples of biological samples include mainly liquids such as blood, saliva, and urine. For example, if the biological sample is blood, examples of the substance to be detected include blood glucose, cortisol, cholesterol, neutral fat, hemoglobin, bilirubin, and trace metals such as copper, zinc and iron. In a state where the biological sample is introduced into the sample space of the sensor and is in contact with the first electrode and the second electrode, the substance to be detected in the biological sample is electrically detected.

  The sensor can be electrically connected to the connection portion of the apparatus main body in either the first posture or the second posture. Each of the connection terminal of the first electrode, the connection terminal of the second electrode, and the connection terminal of the third electrode is exposed to only one of the first surface and the second surface of the sensor. Therefore, the position of the connection terminal of the first electrode, the connection terminal of the second electrode, and the connection terminal of the third electrode in the connection portion differs depending on whether the sensor is in the first attitude or the second attitude.

  In the connection portion, the first terminal is in electrical contact with the connection terminal of the third electrode when the sensor is mounted in the first posture. The second terminal is in electrical contact with the connection terminal of the third electrode when the sensor is mounted as the second posture. The terminal group includes, for example, a pair of terminals that are in electrical contact with the connection terminal of the first electrode and the connection terminal of the second electrode when the sensor is mounted as the first attitude, and the sensor as the second attitude. The first electrode connection terminal and the second electrode connection terminal may be configured by two pairs of terminals that are in electrical contact with each other, or the pair of terminals may be shared. .

  The connection terminal of the third electrode selectively contacts the first terminal or the second terminal depending on whether the sensor connected to the connection portion is in the first posture or the second posture. The sensor attitude determination means determines whether the connection terminal of the third electrode is in contact with the first terminal or the second terminal by monitoring the electrical state of the first terminal or the second terminal. This electrical state may be a change in the resistance value of the first terminal or the second terminal, for example. In addition, even if the first terminal or the second terminal is configured as a pair of electrically independent terminals and the connection terminal of the third electrode is brought into contact with the pair of terminals, the current value can be changed. Good. The sensor attitude determination means determines whether the sensor is in the first attitude or the second attitude depending on whether the connection terminal of the third electrode is in contact with the first terminal or the second terminal.

  Based on the determination result of the sensor posture determination means, the detection means electrically connects a substance to be detected in a biological sample with one of the first electrode and the second electrode as a positive electrode and the other as a negative electrode via a terminal group. Detect.

  (2) The connection terminal of the first electrode is exposed only on either the first surface or the second surface, and the connection terminal of the second electrode is exposed to the first surface or the second surface. It may be exposed only to one of the other. The terminal group is in electrical contact with the connection terminal of the first electrode when the sensor is mounted as the first posture, and the second electrode when the sensor is mounted as the second posture. A third terminal that is in electrical contact with the connection terminal of the second electrode, and when the sensor is mounted in the first posture, the sensor is in electrical contact with the connection terminal of the second electrode, and the sensor is in the second posture. And a fourth terminal that comes into electrical contact with the connection terminal of the first electrode when mounted.

  The connection terminal of the first electrode and the connection terminal of the second electrode are exposed on different surfaces with respect to the first surface or the second surface of the sensor. Therefore, for example, if the connection terminal of the first electrode is exposed to the front side when the sensor is in the first posture, the connection terminal of the second electrode is exposed to the back side. When the sensor is in the second posture, the connection terminal of the first electrode is exposed on the back side, and the connection terminal of the second electrode is exposed on the front side. Therefore, the position where the connection terminal of the first electrode is exposed and the position where the connection terminal of the second electrode is exposed can be arranged symmetrically with respect to the front and back of the sensor.

  As described above, with respect to the first electrode connection terminal and the second electrode connection terminal arranged symmetrically, the third terminal is connected to the first electrode connection terminal when the sensor is mounted as the first posture. When the sensor is mounted in the second posture, it comes into electrical contact with the connection terminal of the second electrode. The fourth terminal is in electrical contact with the connection terminal of the second electrode when the sensor is mounted as the first position, and is electrically connected to the connection terminal of the first electrode when the sensor is mounted as the second position. To touch. Thereby, a terminal group is comprised by a pair of terminal.

  (3) The first electrode is disposed on either the first surface or the second surface of the sensor with respect to the sample space, and the second electrode is disposed on the sample space. The first electrode or the second surface of the sensor is disposed on the other side of the first surface or the second surface of the sensor, and the third electrode is located with respect to the sample space. It may be arranged on the other side. The area of the first electrode exposed to the sample space is wider than the area of the second electrode exposed to the sample space. The detection means sets the first electrode as a negative electrode and the second electrode as a positive electrode based on the determination result of the sensor posture determination means.

  Since the second electrode and the third electrode are arranged on the same surface side of the sensor, and the first electrode is arranged on a surface side different from the third electrode, the area exposed to the sample space in the first electrode is the second It is easy to configure the electrode so as to be larger than the area of the region exposed to the sample space. Since the detection means uses the first electrode as a negative electrode, electrons are sufficiently supplied from the first electrode to the biological sample.

  (4) The apparatus main body may further include sample determination means for determining whether a sample has been introduced into the sample space based on the electrical state of the third electrode. The detection means electrically detects a substance to be detected in a biological sample on the condition that the sample determination means determines that the sample has been introduced into the sample space.

  Thereby, when a biological sample is introduced into the sample space, detection of the substance to be detected is automatically executed.

  (5) A reagent layer containing an enzyme that reacts with a substance to be detected in the biological sample may be provided in a region in contact with the biological sample in the second electrode. That is, the sensor may be configured as a so-called biosensor.

  (6) The enzyme contained in the reagent layer may be at least one of glucose oxidase and glucose dehydrogenase, and the substance to be detected may be glucose in blood. That is, the biological sample detection device may be a blood glucose measurement device using a biosensor.

  According to the present invention, the sensor can be electrically mounted on the connection portion of the apparatus main body in either the first posture or the second posture, and is determined based on the electrical state of the first terminal or the second terminal. Since it can be determined whether the attached sensor is in the first posture or the second posture based on the position of the connection terminal of the third electrode, the positive and negative of the first electrode and the second electrode are suitably determined in the biological sample. The substance to be detected is accurately detected.

FIG. 1 is a perspective view showing an appearance of a blood sugar side device 10 according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the biosensor 11. 3 is a cross-sectional view showing a cross-sectional structure of the biosensor 11 taken along the line III-III in FIG. FIG. 4 is a block diagram showing an internal configuration of the apparatus main body 12. FIG. 5 is an enlarged view showing the configuration of the connecting portion 13. FIG. 6 is a flowchart showing an operation of determining the positive electrode / negative electrode by determining the posture of the biosensor 11. FIG. 7 is an enlarged view showing the connection portion 13 to which the biosensor 11 is attached as the first posture. FIG. 8 is an enlarged view showing the connection portion 13 to which the biosensor 11 is attached as the second posture. FIG. 9 is a cross-sectional view showing a cross-sectional structure of the biosensor 11 in the modification. FIG. 10 is an enlarged view showing the configuration of the connecting portion 13 in the modified example. FIG. 11 is an enlarged view showing the connection portion 13 to which the biosensor 11 is attached as the first posture in the modification. FIG. 12 is an enlarged view showing the connection portion 13 to which the biosensor 11 is attached as the second posture in the modification.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. Each embodiment described below is only an example of the present invention, and it is needless to say that the embodiment of the present invention can be changed as appropriate without departing from the gist of the present invention.

[Blood glucose measuring device 10]
As shown in FIG. 1, the blood glucose measurement device 10 includes a biosensor 11 and a device body 12. The biosensor 11 and the apparatus main body 12 are electrically connected by inserting the biosensor 11 into the connection portion 13 of the apparatus main body 12. The biosensor 11 is replaced for each blood glucose measurement.

[Biosensor 11]
As shown in FIG. 1, the biosensor 11 has an elongated sheet shape. The biosensor 11 is attached to the apparatus main body 12 by inserting one end of the biosensor 11 in the longitudinal direction 101 into the connection portion 13 of the apparatus main body 12. Further, when the biosensor 11 is pulled out in the longitudinal direction 101, the biosensor 11 is removed from the apparatus main body 10.

  Since the front and back of the biosensor 11 are relative, any of them may be front or back. In this embodiment, the side that appears in FIG. 1 is referred to as the front, and the side that does not appear in FIG. 1 is referred to as the back. That is, the biosensor 11 has a sheet shape in which the first surface 21 and the second surface 22 are front and back surfaces. As shown in FIG. 1, the biosensor 11 is in any of the second postures in which the first surface 21 is the front side and the second surface 22 whose front and back are opposite is the front side. However, it can be attached to and detached from the connection portion 13 of the apparatus main body 12.

  As shown in FIG. 2, the biosensor 11 mainly includes a first substrate 23, a first electrode 24, a spacer 25, a second electrode 26, a third electrode 27, and a second substrate 28. The first substrate 23, the first electrode 24, the spacer 25, the second electrode 26, the third electrode 27, and the second substrate 28 are laminated in this order from the upper side, that is, the front side in FIG. It is configured.

[First substrate 23]
As shown in FIG. 2, the first substrate 23 is a sheet having substantially the same shape as the biosensor 11 in plan view. The first substrate 23 is made of an electrically insulating material. Examples of the electrically insulating material include polyesters such as polyethylene terephthalate (PET) and polymethyl methacrylate (PMMA), fluororesin, polycarbonate, and glass.

  One surface of the first substrate 23 constitutes the first surface 21. As will be described later, the first electrode 24 is provided on the surface 32 opposite to the first surface 21. In the first substrate 23, one end side in the longitudinal direction 101 inserted into the connection portion 13 of the apparatus main body 12 is a narrow portion 29 having a narrow width along the direction 102 orthogonal to the longitudinal direction 101. The width of the narrow portion 29 is about 1/3 of the width of the other portion of the first substrate 23.

  On the first surface 21 of the first substrate 23, a pair of colored portions 30 and 31 are formed at both ends in the direction 102. The colored portions 30 and 31 are color-coded with the first surface 21. The coloring portions 30 and 31 are for facilitating visual recognition of the position of a sample introduction port 41 to be described later. Therefore, the coloring portions 30 and 31 are arranged immediately above the sample introduction port 41.

[First electrode 24]
As shown in FIG. 2, the first electrode 24 is provided on the surface 32 of the first substrate 23 opposite to the first surface 21. The first electrode 24 occupies the entire region other than the periphery of the surface 32 of the first substrate 23. Examples of the material for the first electrode 24 include silver / silver chloride, gold, palladium, and platinum. The first electrode 24 is laminated on the surface 32 with respect to the first substrate 23 by a method such as a screen printing method, an inkjet method, sputtering, vacuum deposition, sol-gel method, cluster beam deposition, or PLD.

  In the first electrode 24, a portion corresponding to the narrow portion 29 of the first substrate 23 is a connection terminal 33 that is inserted into the connection portion 13 of the apparatus main body 12. As shown in FIG. 3, none of the spacer 25, the second electrode 26, the third electrode 27, and the second substrate 28 is opposed to the connection terminal 33 and is exposed to the outside of the biosensor 11. Has been. Since the first electrode 24 is formed on the surface 32 side of the first substrate 23, the connection terminal 33 is exposed only on the second surface 22 side of the biosensor 11.

[Second substrate 28]
As shown in FIG. 2, the second substrate 28 is a sheet having substantially the same shape as the biosensor 11 in plan view. The second substrate 28 is made of an electrically insulating material. Examples of the electrically insulating material include polyesters such as polyethylene terephthalate (PET) and polymethyl methacrylate (PMMA), fluororesin, polycarbonate, and glass.

  One surface of the second substrate 28 constitutes the second surface 22. As will be described later, a second electrode 26 and a third electrode 27 are provided on the surface 34 opposite to the second surface 22. In the second substrate 28, one end side in the longitudinal direction 101 inserted into the connection portion 13 of the apparatus main body 12 is a narrow portion 35 having a narrow width along the direction 102. The width of the narrow portion 35 is about 2/3 of the width of the other portion of the second substrate 28.

  Although not shown in the drawings, the second surface 22 of the second substrate 28 is formed with colored portions similar to the colored portions 30 and 31.

[Second electrode 25]
As shown in FIG. 2, the second electrode 25 is provided on the surface 34 of the second substrate 28 opposite to the second surface 22. The second electrode 25 occupies most of the second substrate 28 except for the periphery of the surface 34, but a recessed portion 36 is formed so that the width in the direction 102 becomes narrow at a position corresponding to the space 40 described later. Has been. An example of the material for the second electrode 25 is carbon. Since carbon is used for the second electrode 25, the resistance value of the first electrode 23 employing silver / silver chloride, gold, palladium, platinum or the like is lower than the resistance value of the second electrode 25 made of carbon. Electrons are easily supplied to the blood in the space 40. Of course, the second electrode 25 may be made of a material such as silver / silver chloride, gold, palladium, platinum, etc., like the first electrode 24.

  In the second electrode 22, a portion corresponding to the narrow portion 35 of the second substrate 28 is a connection terminal 37 that is inserted into the connection portion 13 of the apparatus main body 12. The connection terminal 37 is ½ or less of the width of the narrow portion 35, and is disposed on the end side in the direction 102 in the biosensor 11. Thereby, as shown in FIG. 3, the connection terminal 33 and the connection terminal 37 are arranged symmetrically with respect to the front and back of the biosensor 11. None of the spacer 25, the first electrode 24, or the first substrate 23 is opposed to the connection terminal 37 and is exposed to the outside of the biosensor 11. Since the second electrode 25 is formed on the surface 34 side of the second substrate 28, the connection terminal 37 is exposed only on the first surface 21 side of the biosensor 11.

  Although not shown in each figure, GOD and an electron mediator are fixed to a region 38 corresponding to the space 40 in the second electrode 26. Examples of the electron mediator include compounds containing transition metals such as ruthenium, osmium, molybdenum, tungsten, iron, and cobalt. The GOD and the electron mediator are fixed by applying a liquid containing GOD or the like to the second electrode 26 and drying it. The reagent layer in the present invention is realized by laminating GOD and an electron mediator on the second electrode 26.

[Third electrode 27]
As shown in FIG. 2, the third electrode 27 is provided on the surface 34 of the second substrate 28 opposite to the second surface 22. The third electrode 27 is elongated in the longitudinal direction 101 on the surface 34 of the second substrate 28, and one end thereof is bent so as to enter the recessed portion 36 of the second electrode 26. Examples of the material of the third electrode 27 include silver / silver chloride, gold, palladium, platinum, and the like.

  In the third electrode 27, a portion corresponding to the narrow portion 35 of the second substrate 28 is a connection terminal 39 inserted into the connection portion 13 of the apparatus main body 12. The connection terminal 39 is ½ or less of the width of the narrow portion 35 and is disposed in the center of the direction 102 in the biosensor 11. None of the spacer 25, the first electrode 24, or the first substrate 23 is opposed to the connection terminal 39, and is exposed to the outside of the biosensor 11. Since the third electrode 27 is formed on the surface 34 side of the second substrate 28, the connection terminal 39 is exposed only on the first surface 21 side of the biosensor 11.

[Spacer 25]
As shown in FIG. 2, the spacer 25 is a sheet having substantially the same shape as the biosensor 11 in plan view. As the spacer 25, a double-sided tape having electrical insulation is preferably used. By interposing the spacer 25 between the first substrate 23 and the second substrate 28, the first electrode 24, the second electrode 26, and the third electrode 27 are electrically insulated. The spacer 25 has a space 40 extending in the direction 102 at a position corresponding to the coloring portions 30 and 31. That is, the spacer 25 is composed of two sheets separated by the space 40 with respect to the longitudinal direction 101. The space 40 forms a sample space corresponding to the thickness of the spacer 25 between the first electrode 24, the second electrode 26, and the third electrode 27. That is, the space 40 becomes the sample space.

  In the space 40, a part of the first electrode 24, a part of the second electrode 26, and a part of the third electrode 27 are exposed. As described above, since the recessed portion 36 is formed in the region corresponding to the space 40 in the second electrode 26, the area M <b> 1 exposed to the space 40 in the first electrode 24 is the same as that in the second electrode 26. It is wider than the area M2 exposed in the space 40 (area M1> area M2). In FIG. 2, the boundary between the areas corresponding to the area M1 and the area M2 is indicated by a two-dot chain line.

  The first electrode 24, the second electrode 26, and the third electrode 27 are opposed to each other in the space 40 while being separated in the thickness direction of the biosensor 11. As shown in FIG. 1, the space 40 is opened at the end of the biosensor 11, and this opening serves as the sample introduction port 41. Although not shown in FIG. 1, the space 40 is also opened at a position facing the sample introduction port 41. When the sample inlet 41 is exposed to blood, blood flows into the space 40 by capillary action.

[Apparatus body 12]
As shown in FIG. 1, the apparatus main body 12 is an electronic apparatus in which an electronic component is accommodated in a housing 50. A liquid crystal display 51 and operation keys 52, 53, and 54 are arranged on the front surface of the housing 50. The operation keys 52, 53, and 54 are for generating corresponding commands based on user operations. The liquid crystal display 51 displays the state of the apparatus main body 12, measurement results, error display, and the like.

  As illustrated in FIG. 4, the apparatus main body 12 includes a control unit 55. The control unit 55 is an arithmetic unit composed of a CPU, a ROM, a RAM, and the like, and realizes a sensor posture determination unit, a detection unit, and a sample determination unit according to the present invention based on a program stored in the ROM. The control unit 55 is connected to the liquid crystal display 51 and the operation keys 52, 53, and 54 so as to be able to transmit and receive electrical signals. The control unit 55 causes the liquid crystal display 51 to display measurement results and error indications, A predetermined command is generated based on the electrical signal.

  The apparatus main body 12 has a power source 56. The power source 56 is, for example, a primary battery or a secondary battery. A relay circuit 57 is provided between the power supply 56 and the terminals 61, 62, 63, 64 of the connection unit 13. The control unit 55 controls the relay circuit 57 to selectively supply power from the power source 56 to the terminals 61, 62, 63, 64.

[Connector 13]
As shown in FIG. 4, the connection portion 13 is provided with a first terminal 61, a second terminal 62, a third terminal 63, and a fourth terminal 64. As shown in FIG. 5, the connection portion 13 is formed as a rectangular parallelepiped space in the housing 50 of the apparatus main body 12. The space of the connection portion 13 has a shape and a capacity suitable for inserting one end side of the biosensor 11. A first terminal 61, a second terminal 62, a third terminal 63, and a fourth terminal 64 are disposed in the space of the connection portion 13.

  The upper side in FIG. 5 corresponds to the front side of the biosensor 11, and the lower side corresponds to the back side of the biosensor 11. As shown in the figure, in the connection portion 13, the first terminal 61 is disposed at the front side of the center in the direction 102. The first terminal 61 includes a pair of electrically conductive members that are electrically divided into two in the width direction 102, and the pair of electrically conductive members is normally in a non-conductive state. The first terminal 61 protrudes into the space of the connecting portion 13, but when the biosensor 11 is attached, the first terminal 61 is elastically deformed so as to be pushed away by the biosensor 11. When the biosensor 11 is attached to the connection portion 13 in the first posture with the first surface 21 as the front side, the connection terminal 39 of the third electrode 27 is in electrical contact with the pair of conductive members of the first terminal 61. Thus, a conductive state is established between the pair of conductive members.

  As shown in FIG. 5, in the connection portion 13, the second terminal 62 is arranged at the center in the direction 102 and on the back side. The first terminal 61 and the second terminal 62 are offset with respect to the direction 102 so as not to contact each other. The second terminal 62 includes a pair of electrically conductive members that are electrically divided into two in the width direction 102, and the pair of electrically conductive members is normally in a non-conductive state. The second terminal 62 protrudes into the space of the connecting portion 13, but when the biosensor 11 is attached, the second terminal 62 is elastically deformed so as to be pushed away by the biosensor 11. When the biosensor 11 is attached to the connection portion 13 in the second posture with the second surface 22 as the front side, the connection terminal 39 of the third electrode 27 is in electrical contact with the pair of conductive members of the second terminal 62. Thus, a conductive state is established between the pair of conductive members.

  As shown in FIG. 5, in the connection portion 13, the third terminal 63 is arranged on the back side on the left side in FIG. 5 in the direction 102. The third terminal 63 protrudes into the space of the connection portion 13, but when the biosensor 11 is attached, the third terminal 63 is elastically deformed so as to be pushed away by the biosensor 11. When the biosensor 11 is attached to the connection unit 13 in the first posture with the first surface 21 as the front side, the connection terminal 33 of the first electrode 24 is in electrical contact with the third terminal 63. When the biosensor 11 is attached to the connection unit 13 in the second posture with the second surface 22 as the front side, the connection terminal 37 of the second electrode 26 is in electrical contact with the third terminal 63.

  As shown in FIG. 5, in the connection portion 13, the fourth terminal 64 is arranged on the front side on the right side of FIG. 5 in the direction 102. The fourth terminal 64 protrudes into the space of the connecting portion 13, but when the biosensor 11 is attached, the fourth terminal 64 is elastically deformed so as to be pushed away by the biosensor 11. When the biosensor 11 is attached to the connection unit 13 in the first posture with the first surface 21 as the front side, the connection terminal 37 of the second electrode 26 is in electrical contact with the fourth terminal 64. When the biosensor 11 is attached to the connection unit 13 in the second posture with the second surface 22 as the front side, the connection terminal 33 of the first electrode 24 is in electrical contact with the fourth terminal 64.

  As shown in FIG. 4, the connection unit 13 is provided with a switch 58. The switch 58 is not shown in FIG. The switch 58 is a mechanical switch. The switch 58 is turned off when the biosensor 11 is not inserted into the connection unit 13, and is turned on when the biosensor 11 is inserted into the connection unit 13. The control unit 55 determines that the biosensor 11 is attached to the connection unit 13 based on ON / OFF of the switch 58.

[Operation of Blood Glucose Measuring Device 10]
Hereinafter, the operation of the blood glucose measurement device 10 will be described with reference to FIG. The blood glucose measuring device 10 is characterized by determining whether the biosensor 10 is mounted in the first posture or the second posture, the terminal in contact with the first electrode 24 is a negative electrode, and the second electrode 26 The terminal in contact with the positive electrode is the positive electrode. Therefore, in the following, the operation for determining which of the first terminal 63 and the second terminal 64 is the positive electrode or the negative electrode will be described in detail, and the operation for measuring the blood glucose level after that will be briefly described. Explained.

  When the user inserts the biosensor 11 into the connection portion 13 of the apparatus main body 12, the switch 58 provided in the connection portion 13 is turned on (S1). Whether the first surface 21 or the second surface 22 of the biosensor 11 is the front side, that is, whether the biosensor 11 is attached to the apparatus main body 12 in the first posture or the second posture is arbitrary by the user, and the user himself May not be recognized.

When the switch 58 is turned on, the control unit 55 applies a predetermined voltage V ₁ to the first terminal 61. As shown in FIG. 7, when the biosensor 11 is attached in the first posture, the connection terminal 39 of the third electrode 27 contacts the first terminal 61. Thereby, a current flows between a pair of conductive members constituting the first terminal 61. If the current I ₁ flowing through the first terminal 61 is equal to or greater than the predetermined threshold value I ₀ (S2: Yes), the control unit 55 determines that the biosensor 11 is in the first posture. Then, the relay circuit 57 is controlled so that the third terminal 63 becomes a negative electrode and the fourth terminal 64 becomes a positive electrode (S4). The second terminal 62 is elastically deformed so as to be retracted from the connecting portion 13 by being pressed by the second substrate 28.

As shown in FIG. 8, when the biosensor 11 is mounted in the second posture, the connection terminal 39 of the third electrode 27 does not contact the first terminal 61 but is connected to the second terminal 62. Contact. As a result, no current flows between the pair of conductive members constituting the first terminal 61, and the first terminal 61 is elastically deformed so as to be pushed away from the connection portion 13 by being pressed by the second substrate 28. If the current I ₁ flowing through the first terminal 61 is less than the predetermined threshold value I ₀ (S2: No), the control unit 55 stops applying the voltage V ₁ to the first terminal 61 and applies to the second terminal 62. applying a predetermined voltage _{V 2.} Since the connection terminal 39 of the third electrode 27 is in contact with the second terminal 62, a current flows between a pair of conductive members constituting the second terminal 62. If the current I ₂ flowing through the second terminal 62 is equal to or greater than the predetermined threshold value I ₀ (S6: Yes), the control unit 55 determines that the biosensor 11 is in the second posture. Then, the relay circuit 57 is controlled so that the third terminal 63 becomes a positive electrode and the fourth terminal 64 becomes a negative electrode (S7).

For example, if the connection terminal 39 is not in electrical contact with the second terminal 62 due to incomplete mounting of the biosensor 11 or adhesion of foreign matter to the connection terminal 39 of the third electrode 27, the second terminal No current flows between the pair of conductive members constituting 62. Also the control unit 55 by applying a predetermined voltage _{V 2} to the second terminal 62, the current _{I 2} flowing through the second terminal 62 is less than the threshold value _{I 0} (S6: No), the control unit 55, a liquid crystal display 51 displays an error (S8).

  As described above, after one of the first terminal 63 and the second terminal 64 is determined as the positive electrode and the other is determined as the negative electrode, blood is introduced into the space 40, and the blood is supplied to the first electrode 24. When contacting the third electrode 27, the conductive state between the first electrode 24 and the third electrode 27 changes. The controller 55 determines that blood is introduced into the space 40 due to the change in the conductive state, and applies a predetermined voltage to the third terminal 63 and the fourth terminal 64. Thereby, the 1st electrode 24 becomes a negative electrode and the 2nd electrode 26 becomes a positive electrode. In the space 40, GOD fixed to the second electrode 26 decomposes glucose in blood into gluconic acid and hydrogen peroxide, and then decomposes hydrogen peroxide into water and electrons. The electrons are transmitted to the second electrode 26 through the electron mediator. Electrons are supplied from the first electrode 24 into the blood. Based on the current flowing between the first electrode 24 and the second electrode 26 in this way, the control unit 55 calculates the glucose concentration and causes the liquid crystal display 51 to display the result.

[Effects of Embodiment]
According to the present embodiment, the biosensor 11 can be electrically attached to the connecting portion 13 of the apparatus main body 12 in either the first posture or the second posture, and the first terminal 61 or the second terminal 62 Since the position of the connection terminal 39 of the third electrode 27 determined by the electrical state can determine whether the attached biosensor 11 is in the first posture or the second posture, the first electrode 24 and the second electrode The positive / negative of the electrode 26 is suitably determined, and blood glucose is accurately measured.

  Further, the connection terminal 33 of the first electrode 24 is exposed on the second surface 22 side, the connection terminal 37 of the second electrode 26 is exposed on the first surface 21 side, and is connected to the position where the connection terminal 33 is exposed. Since the position where the terminal 37 is exposed is arranged symmetrically with respect to the front and back of the biosensor 11, the terminal group in the present invention is configured by a pair of third terminal 63 and fourth terminal 64.

  Further, since the area M1 exposed to the space 40 in the first electrode 24 is larger than the area M2 of the region exposed to the space 40 in the second electrode 26, electrons are sufficiently transferred from the second electrode 24 to the blood in the space 40. To be supplied.

  In addition, the control unit 55 determines whether a sample has been introduced into the space 40 based on the conductive state between the first electrode 24 and the third electrode 27 and starts measuring blood sugar. When installed, blood glucose measurement is automatically performed.

[Modification]
Hereinafter, modifications of the above-described embodiment will be described. In this modification, as shown in FIG. 9, the side on which the connection terminal 33 of the first electrode 24, the connection terminal 37 of the second electrode 26 and the connection terminal 39 of the third electrode 27 are exposed is all on the first surface 21. This is different from the embodiment described above in that it is on the side. Note that the side where the connection terminal 33 of the first electrode 24, the connection terminal 37 of the second electrode 26, and the connection terminal 39 of the third electrode 27 are exposed may all be the second surface 22 side.

  As shown in FIG. 10, the connection portion 13 is provided with a fifth terminal 65, a sixth terminal 66, a seventh terminal 67, and an eighth terminal 68 instead of the third terminal 63 and the fourth terminal 64. Yes. In the connecting portion 13, the fifth terminal 65 is arranged on the front side on the left side in FIG. 10 in the direction 102, and the sixth terminal 66 is arranged on the left side in FIG. The fifth terminal 65 and the sixth terminal 66 are offset with respect to the direction 102 so as not to contact each other. In the connection portion 13, the seventh terminal 67 is arranged on the front side in the right direction in FIG. 10 in the direction 102, and the eighth terminal 68 is arranged on the right side in FIG. The seventh terminal 67 and the eighth terminal 68 are offset with respect to the direction 102 so as not to contact each other.

  As shown in FIG. 11, when the biosensor 11 is attached to the connection portion 13 in the first posture with the first surface 21 as the front side, the connection terminal 33 of the first electrode 24 is electrically connected to the fifth terminal 65. The connection terminal 37 of the second electrode 26 is in electrical contact with the seventh terminal 67. Further, the connection terminal 39 of the third electrode 27 is in electrical contact with the first terminal 61. Therefore, the control unit 55 determines that the fifth terminal 65 is a negative electrode and the seventh terminal 67 is a positive electrode on the condition that the connection terminal 39 of the third electrode 27 is in electrical contact with the first terminal 61. decide.

  As shown in FIG. 12, when the biosensor 11 is attached to the connection portion 13 in the second posture with the second surface 22 as the front side, the connection terminal 33 of the first electrode 24 is electrically connected to the eighth terminal 68. The connection terminal 37 of the second electrode 26 is in electrical contact with the sixth terminal 66. Further, the connection terminal 39 of the third electrode 27 is in electrical contact with the second terminal 62. Therefore, on the condition that the connection terminal 39 of the third electrode 27 is in electrical contact with the second terminal 62, the control unit 55 determines the eighth terminal 68 as a negative electrode and the sixth terminal 66 as a positive electrode. decide.

  Even in such a modification, the biosensor 11 can be electrically attached to the connection portion 13 of the apparatus main body 12 in either the first posture or the second posture, and the first terminal 61 or the second terminal 62 can be attached. Since it is possible to determine whether the attached biosensor 11 is in the first posture or the second posture based on the position of the connection terminal 39 of the third electrode 27 determined by the electrical state of the first electrode 24 and the first electrode 24. The positive and negative of the two electrodes 26 are suitably determined, and blood glucose is accurately measured.

10 ... blood glucose measurement device (biological sample detection device)
11 ... Biosensor (sensor)
DESCRIPTION OF SYMBOLS 12 ... Device main body 13 ... Connection part 21 ... 1st surface 22 ... 2nd surface 24 ... 1st electrode 26 ... 2nd electrode 27 ... 3rd electrode 33 ... Connection terminal 37 ... connection terminal 39 ... connection terminal 40 ... space (biological sample)
55... Control unit (sensor attitude determination means, detection means, sample determination means)
61 ... 1st terminal 62 ... 2nd terminal 63 ... 3rd terminal (terminal group)
64 ... 4th terminal (terminal group)
65 ... 5th terminal (terminal group)
66 ... 6th terminal (terminal group)
67 ... 7th terminal (terminal group)
68 ... 8th terminal (terminal group)

Claims (6)

The sensor having a sheet shape in which the first surface and the second surface form front and back surfaces and a sample space into which a biological sample is introduced is the first posture in which the first surface is the front side or the second surface is the front side. In any of the second postures, a biological sample detection device provided detachably with respect to the connection portion of the device body,
The sensor
A region in contact with the biological sample is exposed in the sample space, and a first electrode whose connection terminal is exposed only on either the first surface or the second surface;
A region in contact with the biological sample is exposed in the sample space, and a second electrode whose connection terminal is exposed only on either the first surface or the second surface;
A region in contact with the biological sample is exposed in the sample space, and a third electrode whose connection terminal is exposed only on either the first surface or the second surface;
The connection part of the device body is
A first terminal that is in electrical contact with the connection terminal of the third electrode when the sensor is mounted as the first posture;
A second terminal that is in electrical contact with the connection terminal of the third electrode when the sensor is mounted as the second posture;
A terminal group that selectively and electrically contacts the connection terminal of the first electrode and the connection terminal of the second electrode when the sensor is mounted in the first attitude or the second attitude; Is,
The device body is
By determining whether the third electrode is in electrical contact with the first terminal or the second terminal based on the electrical state of the first terminal or the second terminal, the sensor is in the first posture. Sensor posture determination means for determining whether the second posture or the second posture;
Based on the determination result of the sensor posture determination means, either one of the first electrode and the second electrode is set as a positive electrode and the other is set as a negative electrode through the terminal group. And a biological sample detection device. The connection terminal of the first electrode is exposed only on either the first surface or the second surface,
The connection terminal of the second electrode is exposed only on the other of the first surface and the second surface,
The terminal group is
When the sensor is mounted as the first posture, it is in electrical contact with the connection terminal of the first electrode, and when the sensor is mounted as the second posture, it is electrically connected to the connection terminal of the second electrode. A third terminal that makes electrical contact,
When the sensor is mounted as the first posture, it electrically contacts the connection terminal of the second electrode, and when the sensor is mounted as the second posture, the connection terminal of the first electrode and the electric terminal The biological sample detection device according to claim 1, wherein the biological sample detection device has a fourth terminal that comes into contact with each other. The first electrode is disposed on either the first surface or the second surface of the sensor with respect to the sample space;
The second electrode is disposed on the other side of the first surface or the second surface of the sensor with respect to the sample space;
The third electrode is disposed on the other side of the first surface or the second surface of the sensor with respect to the sample space;
The area of the first electrode exposed to the sample space is wider than the area of the second electrode exposed to the sample space,
The biological sample detection apparatus according to claim 1, wherein the detection unit uses the first electrode as a negative electrode and the second electrode as a positive electrode based on a determination result of the sensor posture determination unit. The apparatus main body further includes sample determination means for determining whether a sample is introduced into the sample space based on an electrical state of the third electrode.
4. The detection unit according to claim 1, wherein the detection unit electrically detects a substance to be detected in a biological sample on the condition that the sample determination unit determines that the sample has been introduced into the sample space. The biological sample detection device according to 1.   The biological sample detection according to any one of claims 1 to 4, wherein a reagent layer containing an enzyme that reacts with a substance to be detected in the biological sample is provided in a region in contact with the biological sample in the second electrode. apparatus. The biological sample detection apparatus according to claim 5, wherein the enzyme contained in the reagent layer is at least one of glucose oxidase and glucose dehydrogenase, and the substance to be detected is glucose in blood.

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