JP4972956B2 - Biosensor system and measuring instrument - Google Patents

Description

  The present invention relates to a biosensor system for measuring biological information of a biological material supplied to a biosensor chip and a measuring device therefor.

  Conventionally, research on bioelectronics in which biological functions are applied to the electronics field has been progressing. The biosensor chip in the bioelectronics field is a device that uses an excellent molecular identification function of a living body, and is promising in the future as being capable of measuring chemical substances quickly and easily. Such a biosensor chip is applied as a sensor for measuring a small amount of sample. For example, the biosensor chip is used for a home health check (self-care) for self-management and prevention of diabetes by measuring a blood glucose level and a urine sugar level, or industrially. Is widely used in applications such as sampling quality inspection of products on the production line.

  As a specific example of measurement, a sample containing a measurement target substance is collected and dropped into a reaction part, and for example, a reduction product generated by an enzyme reaction is oxidized to detect and detect an element current value due to the oxidation. A measured value equivalent to the element current value is obtained by referring to a data table, and is output and displayed (see Patent Document 1).

  Such a measuring instrument for measuring the element current value is provided with a sensor insertion determination circuit as a determination means for recognizing whether or not the sensor chip is inserted into the device body and is in a measurable state. There has been proposed a device configured to measure a measured value of an element current value of a measurement target substance after detecting that a chip is inserted. FIG. 6 shows the configuration of a biosensor device that can detect that a sensor chip has been inserted.

  As shown in FIG. 6, the measuring device 70 mainly supplies the blood glucose level measurement circuit 72 via the blood glucose level measurement circuit 72 that measures the blood glucose level from the measurement target substance blood and the sensor electrodes 62 and 63 of the biosensor chip 60. Connector electrode A and connector electrode B that enable electrical connection of the sensor, a sensor insertion determination circuit 71 that determines insertion of the biosensor chip 60, and a sensor electrode 64 of the biosensor chip 60. A connector electrode C and a connector electrode D enabling electrical connection are provided.

  On the other hand, the biosensor chip 60 inserted into the measuring instrument 70 mainly includes a sensor electrode 62 that contacts the connector electrode A, a sensor electrode 63 that contacts the connector electrode B, a sensor electrode 64 that contacts the connector electrode C, and the connector electrode D. The blood glucose level sensor unit 61 is provided so as to be electrically connected to the sensor electrodes 62 and 63.

  When the biosensor chip 60 is inserted into the measuring instrument 70, the sensor electrode 64 causes the connector electrode C and the connector electrode D to be short-circuited, so that the sensor insertion determination circuit 71 determines the insertion of the biosensor chip 60. After discriminating the sensor insertion, the user drops blood on the blood glucose level sensor unit 61, and charges are generated by the enzymatic reaction of the dropped blood. When a predetermined voltage is applied from the blood glucose level measurement circuit 72 after being left for a predetermined time, an element current corresponding to the enzyme reaction flows. The blood glucose level is measured by displaying a value equivalent to the element current value generated by the oxidation on a display unit (not shown) of the measuring device 70.

  Further, in Patent Document 2, in order to determine whether a sample piece is properly inserted, two contact points are provided for each of the detection electrode and the excitation electrode, and one of the contact points is short-circuited to insert the sample piece. A biosensing meter set to detect whether or not is detected.

  Furthermore, Patent Document 3 discloses a measuring apparatus configured to determine whether or not a measurement sensor is mounted using a thermistor having a large change in electrical resistance value with respect to a temperature change. A thermistor and a temperature detection circuit are provided on the measurement device side, and when the measurement sensor is mounted on the measurement device, the thermistor is connected to the temperature detection circuit and outputs a temperature detection signal having a voltage value corresponding to the temperature measurement signal from the thermistor. Thus, the mounting of the measurement sensor is determined.

JP-A-11-108879 JP-T-08-504953 JP 2002-257782 A

However, in the measuring instrument 70 shown in FIG. 6, in addition to the connector electrodes A and B on the blood glucose level measurement circuit 72 side, two new electrodes, the connector electrodes C and D, must be provided for the sensor insertion determination circuit. Moreover, according to the measuring apparatus described in Patent Document 2, it is necessary to provide four contact points in order to determine whether the sample piece is correctly inserted.
As described above, four terminals are required for the sensor in the measuring apparatus, and as the number of mechanical contacts increases, the reliability is lowered and the product life is shortened.
Moreover, in patent document 1, an element reaction sensor member (biosensor chip) requires three terminals, and its size increases.

  Accordingly, an object of the present invention is to determine that a biosensor chip has been inserted, and to measure biometric information of a biological material supplied to the biosensor chip and a measuring device thereof. The purpose is to improve the reliability of the measuring instrument and extend the product life.

In order to solve the above problems, a biosensor system according to the present invention is a biosensor system comprising a biosensor chip and a measuring instrument that measures biological information of a biological material supplied to the biosensor chip. ,
The biosensor chip is
A reaction portion formed to be electrically connected to a plurality of sensor electrodes and supplied with the biological material;
The measuring instrument is
An insertion determination circuit for determining attachment / detachment of the biosensor chip;
A biological information measuring circuit for measuring the biological information;
An insertion part into which the biosensor chip can be inserted;
An insertion determination circuit side connector electrode that is electrically connected to the insertion determination circuit and provided so as to contact the first sensor electrode by inserting the biosensor chip into the insertion portion;
A measurement circuit side connector electrode that is electrically connected to the biological information measurement circuit and is provided so as to contact the second sensor electrode by inserting the biosensor chip into the insertion portion;
The biosensor chip includes a ground electrode provided so as to be in electrical contact with the first sensor electrode when the biosensor chip is inserted into the insertion portion.

  In addition, the sensor electrode is preferably formed of a sensor electrode member having an electric resistance higher than that of the conductive metal, particularly carbon.

Further, the measuring instrument according to the present invention includes an insertion determination circuit for determining attachment / detachment of a biosensor chip,
A biological information measuring circuit for measuring biological information;
An insertion part into which the biosensor chip can be inserted;
An insertion determination circuit side connector electrode that is electrically connected to the insertion determination circuit and provided so as to contact the first sensor electrode by inserting the biosensor chip into the insertion portion;
A measurement circuit side connector electrode that is electrically connected to the biological information measurement circuit and is provided so as to contact the second sensor electrode by inserting the biosensor chip into the insertion portion;
The biosensor chip includes a ground electrode provided so as to be in electrical contact with the first sensor electrode when the biosensor chip is inserted into the insertion portion.

  Further, the measuring device has voltage switching means for switching a voltage applied to the connector electrode on the insertion determination circuit side to a reference voltage or a ground potential, and the voltage switching means is the biosensor chip by the sensor insertion determination circuit. It is preferable that the switch is set to the ground potential after the insertion determination.

According to the present invention, the measuring instrument has a configuration in which the ground electrode is used as both the sensor insertion determination circuit and the blood glucose level measuring circuit, and the four connector electrodes provided in the conventional measuring instrument are reduced to three. Therefore, since the number of electrode terminals is reduced as compared with the conventional measuring instrument, the number of mechanical contacts is reduced, the reliability is improved, and the product life is extended.
In addition, since the first sensor electrode of the biosensor chip can be shared by the sensor insertion determination circuit and the blood glucose level measurement circuit, the conventional three electrodes can be reduced to two, thereby reducing the size of the biosensor chip. It is possible to reduce the manufacturing cost.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a biosensor system and a measuring device thereof according to the present invention will be described in detail with reference to the drawings. In the present embodiment, blood is used as an example of the biological material supplied to the biosensor chip, and the measuring device is described using a biosensor system that is a measuring device that measures a blood glucose level in the blood as an example. .

FIG. 1 is an external perspective view of the biosensor system according to the present embodiment.
FIG. 2 is a block diagram showing a configuration of a main part of the biosensor system of FIG.
FIG. 3 is a flowchart for explaining blood glucose level measurement processing in the biosensor system according to this embodiment.
FIG. 4 is an equivalent circuit diagram of the main part of the biosensor system according to the present embodiment.
FIG. 5 is a graph showing the time course of the voltage applied to the measuring instrument of the biosensor system according to the present embodiment.

First, the external appearance of the biosensor system 10 according to the present embodiment will be described.
The biosensor system 10 shown in FIG. 1 discriminates that the detachable biosensor chip 20 and the biosensor chip 20 are inserted, and the blood sugar level in the blood (biological material) supplied to the biosensor chip 20. And a measuring instrument 1 for measuring (biological information).

  As shown in FIG. 1, in the measuring instrument 1, an insertion part 5 into which a biosensor chip 20 is inserted is opened at the front center of a housing 4 composed of a lower case 2 and an upper case 3. Circular operation buttons 6 and 6 are provided at the left and right rear as the center.

  Further, a rectangular display unit 7 for displaying the measured blood glucose level is provided further behind the operation buttons 6 and 6. Although details will be described later, when the biosensor chip 20 is inserted into the insertion portion 5, electrodes (insertion determination circuit side connector electrodes 13) that can be electrically contacted with the respective electrodes provided on the biosensor chip 20. , A measurement circuit side connector electrode 11 and a ground electrode 12) are provided (see FIG. 2).

  As shown in FIG. 1, when the biosensor chip 20 is inserted into the insertion portion 5 of the measuring instrument 1 on the stick-like insulating substrate 24 that can be inserted into the insertion section 5 of the measuring instrument 1, A first sensor electrode 21 and a second sensor electrode 22 that are partly in electrical contact with each electrode of the measuring instrument 1 are provided substantially in parallel along the longitudinal direction.

  Furthermore, blood (biological substance) is supplied in the vicinity of the end opposite to the side inserted into the measuring instrument so as to be electrically connected to the first sensor electrode 21 and the second sensor electrode 22. The reaction part 23 is provided.

  The electrodes 21 and 22 are covered with an insulating film 25 except for the portions that are in electrical contact with the electrodes of the measuring instrument 1 and the portions that are electrically connected to the blood glucose level sensor unit 23. May be.

Next, an example of a method for forming the biosensor chip 20 will be described.
The insulating substrate 24 forming the main body of the biosensor chip 20 is made of ceramic material, glass, paper, biodegradable material (for example, microbially produced polyester), and plastic material such as polyethylene terephthalate.

  On the insulating substrate 24, a pair of sensor electrodes composed of the first sensor electrode 21 and the second sensor electrode 22 are formed in a pattern in order to take out an element current generated by an enzyme reaction such as oxidoreductase. . In addition to conductive metals such as silver, gold, palladium, platinum, nickel, copper, and iridium, these sensor electrode members have a higher electrical resistance than conductive metals, but carbon and conductive plastic Non-metallic materials such as polyacetylene, poly- [rho] -phenylene, polypyrrole, polythiophene, and a plastic compounded with conductive metal particles may also be used. A pattern is formed on these sensor electrode members by screen printing, sticking, vapor deposition, sputtering, or the like. In addition, since the biosensor chip 20 is normally used disposable, carbon that is inexpensive and can be easily formed with an electrode is more preferable.

  The blood glucose level sensor unit 23 can be formed of a mixture of an oxidoreductase and an electron carrier (mediator), for example, a mixture of glucose oxidase and potassium ferricyanide.

  In the case of a disposable glucose biosensor using glucose oxidase, which is a typical oxidoreductase, in many cases, measurement is performed by collecting a sample of an object to be measured.

  The method of indirectly obtaining the glucose concentration by the device current value by the oxidation-reduction reaction is well known, and by the glucose oxidase action, ferricyan ion is reduced to ferrocyan ion, and at the same time, gluconolactone is generated, and ferrocyan ion is obtained. The device current value is detected and measured by oxidation.

Next, the configuration of the main part of the biosensor system 10 according to the present embodiment will be described in detail.
As shown in FIG. 2, the measuring instrument 1 includes a sensor insertion determining circuit 14 as determining means for recognizing whether or not the biosensor chip 20 is inserted into the measuring instrument main body and is ready for measurement. Then, after detecting that the biosensor chip 20 has been inserted, a blood glucose level measurement circuit 15 that measures a measured value (ie, blood glucose level) of an element current value of blood that is a measurement target substance is provided.

  Further, the insertion determination circuit side provided to come into contact with the first sensor electrode 21 provided on the biosensor chip 20 by being electrically connected to the sensor insertion determination circuit 14 and inserting the biosensor chip 20. A connector electrode 13 is provided.

  Further, the measurement circuit side connector electrode 11 provided so as to come into contact with the second sensor electrode 22 provided on the biosensor chip 20 is connected to the blood sugar level measurement circuit 15 and the biosensor chip 20 is inserted. I have.

  Furthermore, a ground electrode 12 is provided that is connected to the ground potential GND and is in contact with the first sensor electrode 21 provided on the biosensor chip 20 when the biosensor chip 20 is inserted.

  As described above, the measuring instrument 1 has a configuration in which the ground electrode 12 is shared by the sensor insertion determination circuit 14 and the blood glucose level measurement circuit 15. Thus, since the four connector electrodes provided in the conventional measuring instrument are reduced to three, the measuring instrument 1 of the biosensor system according to the present embodiment has the number of electrode terminals as compared with the conventional measuring instrument. This reduces the number of mechanical contacts, improves reliability, and increases product life.

  Further, as shown in FIG. 2, the first sensor electrode 21 on the biosensor chip 20 side can also be shared by the sensor insertion determination circuit 14 and the blood glucose level measurement circuit 15, so that the conventional three electrodes are divided into two. Can be reduced. Therefore, the biosensor chip 20 can be miniaturized and the manufacturing cost can be reduced.

  In the present embodiment, when the biosensor chip 20 is inserted into the measuring instrument 1, the insertion determination circuit side connector electrode 13 after insertion and the ground electrode 12 connected to the ground potential GND and the first circuit state from the open circuit state before insertion. A closed circuit state due to a short circuit with one sensor electrode 21 is formed, and when connected to the reference voltage Ref, a voltage is applied between the connector electrode 13 on the insertion determination circuit side and the ground electrode 12, and the sensor insertion determination circuit 14 The insertion of the biosensor chip 20 is discriminated.

  As a part for controlling the entire measuring instrument 1, the measuring instrument 1 is provided with a control unit (not shown) composed of a CPU (Central Processing Unit) using a microcomputer. This control unit includes a current-voltage conversion circuit that converts the device current detected by the blood glucose level measurement circuit 15 into a voltage value, an amplification circuit that amplifies the converted voltage signal, and an arithmetic unit that performs arithmetic processing based on the input data signal The value processed by the calculation unit is displayed on the display unit 7 as measurement data. The CPU performs overall control based on signals input / output from each circuit in each unit through the I / O port.

  In addition, a pull-up resistor R1 is connected between the insertion determination circuit side connector electrode 13 and the sensor insertion determination circuit 14, and between the pull-up resistance R1 and the reference voltage Ref, the insertion determination circuit side connector electrode 13 and There is provided voltage switching means (hereinafter referred to as a switch) SW for switching the voltage applied to the ground electrode 12 to the reference voltage Ref or the ground potential GND.

  By connecting the pull-up resistor R1, the input level to the sensor insertion determination circuit 14 can be set to “High” in a state where the switch SW is connected to the reference voltage Ref.

  When the biosensor chip 20 is inserted from the insertion portion 5 while the switch SW is connected to the reference voltage Ref, the insertion determination circuit side connector electrode 13 and the ground electrode 12 are short-circuited by the first sensor electrode 21. Then, “Low” is input to the sensor insertion determination circuit 14. As described above, the measuring instrument 1 can determine that the biosensor chip 20 has been inserted from the insertion portion 5 by changing the input level to the sensor insertion determination circuit 14 from “High” to “Low”.

  By the way, the biosensor chip 20 is normally a disposable type, and if the electrodes (the first sensor electrode 21 and the second sensor electrode 22) are made of metal, the cost becomes high. For this reason, it is desired to be made of a member having a low cost (for example, carbon).

  Hereinafter, the biosensor chip 20 made of carbon, which is a simple and inexpensive member for manufacturing, will be described as an example.

  Since carbon is a member having a higher electric resistance value than the conductive metal, when the insertion determination circuit side connector electrode 13 and the ground electrode 12 are short-circuited by the first sensor electrode 21, the insertion determination circuit side connector electrode The first sensor electrode 21 has a potential due to the resistance between the electrodes 13 and the ground electrode 12.

  When the first sensor electrode 21 has a potential (V0) during blood glucose level measurement, a predetermined voltage applied between the measurement circuit side connector electrode 11 and the ground electrode 12 from the blood glucose level measurement circuit 15 during blood glucose level measurement. Where only the voltage (Vset) should be applied, the potential (−V0) of the first sensor electrode 21 is also applied.

  For this reason, when the biosensor chip 20 in which the electrode is formed of carbon is employed as in this embodiment, the biosensor chip 20 is inserted into the insertion portion 5 of the measuring instrument 1 and the biosensor by the sensor insertion determination circuit 14 is used. After the insertion determination of the chip 20, the switch SW is switched from the reference voltage Ref to the ground potential GND, so that the insertion determination circuit side connector electrode 13 and the ground electrode 12 are set to have the same potential. That is, the reference voltage Ref is not applied during the blood glucose level measurement by the blood glucose level measurement circuit 15.

  The measuring instrument 1 shown in FIG. 2 is in a state where the switch SW is switched from the reference voltage Ref to the ground potential GND, and FIG. 4A shows an equivalent circuit thereof.

  When the electric resistance values of the first sensor electrode 21 and the second sensor electrode 22 are considered, the resistance of the first sensor electrode 21 is R101 (about 2.7 [KΩ]), and the resistance of the second sensor electrode 22 is R100. (About 2.7 [KΩ]).

  When the carbon electrode resistance between the insertion determination circuit side connector electrode 13 and the ground electrode 12 is R102 (about 100 [Ω]), and R101 >> R102, the insertion determination circuit side connector electrode 13 and the ground electrode 12 are interposed. In a state where the reference voltage Ref is always applied, the insertion discriminating circuit side connector electrode 13 and the ground electrode 12 are short-circuited via the first sensor electrode 21, so that the reference voltage Ref is R1 and R102 at the first sensor electrode 21. Voltage V0 (= Ref × R102 / 2 (R1 + R102)) is applied.

  Although 0 [V] should be applied during the standing time during blood glucose level measurement, the ground potential is set between the ground electrode 12 and the measurement circuit side connector electrode 11 because the ground electrode 12 is set to the ground potential GND. GND (0V [V])-V0 is applied.

  Furthermore, during the application time, a predetermined voltage (Vset) must be applied from the blood glucose level measurement circuit 15, and (Vset) −V0 is applied to the ground electrode 12 and the measurement circuit side connector electrode 11. turn into.

  For this reason, there is a possibility that the measured blood glucose level is output as a low value. Therefore, the switch SW switches the reference voltage Ref to the ground potential GND during the application time and the leaving time, thereby inserting the connector electrode on the insertion determination circuit side. 13 and the ground electrode 12 are set so as to be equipotential and V0 = 0 [V].

  The same effect can be obtained by realizing the equivalent circuit shown in FIG. That is, the switch SW is provided between the insertion determination circuit side connector electrode 13 and the pull-up resistor R1 so that the insertion determination circuit side connector electrode 13 can be selected to the ground potential GND, or the sensor insertion determination circuit 14 is 0. It can be configured to output [V].

  If the first sensor electrode 21 and the second sensor electrode 22 are formed of a silver paste having a low electric resistance value in addition to the member having an electric resistance value higher than that of a metal such as carbon, the insertion discrimination circuit side connector Measurement errors due to the potential difference between the electrode 13 and the ground electrode 12 can be reduced, and it is not necessary to provide the switch SW, and the work of switching from the reference voltage Ref to the ground potential GND can be omitted. However, since the silver paste is relatively expensive than carbon, the cost of the biosensor chip is increased.

  Further, by constantly applying the reference voltage Ref, the input level of the sensor insertion determination circuit 14 changes from “Low” to “High” even when the biosensor chip 20 is detached from the insertion portion 5 during blood glucose level measurement. Since it changes, it can be easily determined that the biosensor chip 20 has been attached or detached.

Next, blood glucose level measurement processing by the measuring instrument 1 will be described with reference to FIGS. 2, 3 and 5.
First, the biosensor chip 20 is inserted from the insertion portion 5 of the measuring instrument 1 (step S1).

  At the stage of inserting the biosensor chip 20, the collected blood for measurement is not yet dropped on the blood glucose level sensor unit 23 on the biosensor chip 20 side.

  Accordingly, the circuit between the first sensor electrode 21 and the second sensor electrode 22 of the biosensor chip 20 remains an open circuit. By inserting the biosensor chip 20, the first sensor electrode 21 is connected to the insertion determination circuit side connector electrode 13 and the ground electrode 12 on the measuring instrument 1 side, and at the same time, the second sensor electrode 22 is connected to the connector measurement circuit side connector electrode 11. Is done. As a result, a short circuit is formed to form a closed circuit, the reference voltage Ref is connected to the sensor insertion determination circuit 14, and the measuring instrument 1 is activated.

  The control unit recognizes that the biosensor chip 20 has been inserted by changing the input level of the sensor insertion determination circuit 14 from “High” to “Low” (step S2).

  With this biosensor chip 20 insertion authorization, a voltage (Vset) is applied between the ground electrode 12 and the measurement circuit side connector electrode 11 by a control signal output from the control unit. At the same time, the switch SW is switched from the reference voltage Ref to the ground potential GND (step S3).

  Next, when blood for measurement is dropped onto the blood glucose level sensor unit 23 of the biosensor chip 20 (step S4), the ground electrode 12 and the measurement circuit side connector electrode 11 are short-circuited to form a closed circuit.

  Based on this closing signal, the control unit determines that the blood is dropped (step S5), and interrupts the supply of the voltage (Vset) that has been applied between the ground electrode 12 and the measurement circuit side connector electrode 11 until that time (step S6). .

  In the standing time, the supply of the applied voltage (Vset) is interrupted in order to store the electric charge generated by the chemical change of blood to be measured. In synchronization with this, the control unit starts counting the remaining time until the end of measurement, for example, 30 seconds, starting from a preset time numerical value.

  The counted remaining time is displayed on the display unit 7 so that the user can recognize it. When the remaining time reaches the set time, a voltage (Vset) having a value set in advance for reaction is applied again between the ground electrode 12 and the measurement circuit side connector electrode 11 (step S7).

  By this voltage application again, the blood dropped on the blood glucose level sensor unit 23 is oxidized by the reduced product generated by the enzyme reaction, and detects and captures the device current value generated by the oxidation (step S8).

  After the voltage (Vset) is applied for a certain period of time, the blood glucose level measurement circuit 15 converts the detected device current value into a voltage value, and amplifies the converted voltage value by the amplifier circuit.

  With reference to the data table corresponding to the amplified voltage, the calculation result data in the calculation unit is displayed on the display unit 7. Then, the switch SW is switched again from the ground potential GND to the reference voltage Ref (step S9).

  After the measurement result data is displayed for a certain period of time, when the biosensor chip 20 is removed from the measuring instrument 1 by switching the switch SW from the ground potential GND to the reference voltage Ref, the input level of the sensor insertion determination circuit 14 is changed. Since it changes from “Low” to “High”, it is possible to recognize the removal of the biosensor chip 20 and automatically turn off the measuring instrument 1.

  Even if the biosensor chip 20 is left without being removed, the measuring instrument 1 can be set to be automatically turned off if it is not removed for a predetermined time.

  As shown in FIG. 5, in this embodiment, after the insertion of the biosensor chip 20 is recognized, the switch SW is switched from the reference voltage Ref to the ground potential GND, and after measuring the blood glucose level, the reference voltage is again set from the ground potential GND. It is configured to be switched to Ref (see voltage change indicated by a dotted line in FIG. 5).

  Therefore, from the insertion of the biosensor chip 20 to the measurement of the blood glucose level, it is based on the interelectrode resistance between the insertion determination circuit side connector electrode 13 and the ground electrode 12 by the first sensor electrode 21 formed of carbon. The potential difference is not generated.

  Therefore, the application voltage is set to 0 [V] during the standing time (step S6), and the predetermined voltage (Vset) is set to be applied reliably during the application time (step S7). A more accurate blood sugar level (measured value) can be obtained.

  By providing a voltage switching means (switch SW) that is set to switch the voltage applied to the connector electrode on the insertion determination circuit side from the reference voltage to the ground potential after the insertion determination of the biosensor chip by the sensor insertion determination circuit, Between the insertion of the biosensor chip and the measurement of biological information, the insertion discrimination circuit side connector electrode and the ground electrode are connected via the first sensor electrode (having a higher electric resistance value than that of the conductive metal). Since a potential difference (for the first sensor electrode which is a member) does not occur, a more accurate measurement value can be obtained.

It is an external appearance perspective view of the biosensor system concerning this embodiment. It is a block diagram of the principal part of the biosensor system which concerns on this embodiment. It is a flowchart explaining the blood glucose level measurement process which the measuring device in the biosensor system which concerns on this embodiment performs. It is an equivalent circuit diagram of the measuring device in the biosensor system concerning this embodiment. It is the graph which showed the time course of the voltage applied to the measuring device in the biosensor system concerning this embodiment. It is a block diagram of the principal part of the conventional measuring device and biosensor chip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measuring device 5 Insertion part 11 Measurement circuit side connector electrode 13 Insertion discrimination circuit side connector electrode 12 Ground electrode 14 Sensor insertion discrimination circuit 15 Blood glucose level measurement circuit (biological information measurement circuit)
Ref Reference voltage GND Ground potential 20 Biosensor chip 21 First sensor electrode 22 Second sensor electrode 23 Blood glucose level sensor part (biological substance sensor part)
R1 pull-up resistor SW switch (voltage switching mechanism)

Claims (4)

A biosensor system comprising: a biosensor chip; and a measuring instrument that measures biological information of a biological material supplied to the biosensor chip,
The biosensor chip is
A reaction part formed to be electrically connected to a plurality of sensor electrodes and supplied with the biological material;
The measuring instrument is
A reference voltage source;
An insertion determination circuit for determining attachment / detachment of the biosensor chip;
A switch for switching a voltage supplied to the insertion determination circuit between a first potential supplied from the reference voltage source and a second potential different from the first potential;
A biological information measuring circuit for measuring the biological information;
An insertion part into which the biosensor chip can be inserted;
An insertion determination circuit side connector electrode that is electrically connected to the insertion determination circuit and provided so as to contact the first sensor electrode by inserting the biosensor chip into the insertion portion;
A measurement circuit side connector electrode that is electrically connected to the biological information measurement circuit and is provided so as to contact the second sensor electrode by inserting the biosensor chip into the insertion portion;
A ground electrode provided to be in electrical contact with the first sensor electrode by inserting the biosensor chip into the insertion portion;
I have a,
When the biosensor chip is not inserted into the insertion portion, the switch is connected to the reference voltage source side,
After said biosensor chip is detected by the insertion determining circuit that is inserted into the insertion portion, the switch biosensor system characterized in Rukoto connected to the second potential. The first sensor electrode and the second sensor electrode are formed of a sensor electrode member made of a conductive metal or a non-metallic material having an electric resistance higher than that of the conductive metal. The biosensor system according to 1. The biosensor system according to claim 2, wherein the sensor electrode member is carbon. A reference voltage source;
An insertion discriminating circuit for discriminating whether the biosensor chip is attached or detached;
A biological information measuring circuit for measuring biological information;
An insertion part into which the biosensor chip can be inserted;
An insertion determination circuit side connector electrode that is electrically connected to the insertion determination circuit and provided so as to contact the first sensor electrode by inserting the biosensor chip into the insertion portion;
A measurement circuit side connector electrode that is electrically connected to the biological information measurement circuit and is provided so as to contact the second sensor electrode by inserting the biosensor chip into the insertion portion;
A ground electrode provided to be in electrical contact with the first sensor electrode by inserting the biosensor chip into the insertion portion;
Voltage switching means capable of switching a voltage applied to the insertion discriminating circuit side connector electrode to a reference voltage or a ground potential supplied from the reference voltage source;
The measuring device , wherein the voltage switching means is set to switch from the reference voltage to the ground potential after the insertion determination circuit determines the insertion of the biosensor chip .

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