JP4856009B2 - Biosensor - Google Patents

Description

  The present invention relates to a biosensor capable of quantitative analysis by measuring the amount of a substrate component in a specimen.

  Conventionally, biosensors have been devised for measuring blood sugar levels and the like of specimens (see, for example, Patent Document 1 and Patent Document 2). According to this biosensor, a blood glucose level or the like can be measured by measuring a current value between the measurement working electrode and the measurement counter electrode when the reaction part reacts with blood or the like introduced from the supply port.

However, according to the conventional biosensor, due to the insufficient amount of collected blood and the like, the amount of blood and the like introduced to the reaction part is small, so that accurate measurement cannot be performed. there were. In other words, even though the amount of blood introduced to the reaction part is not necessary for accurate measurement, the blood glucose level is measured and output, thereby recognizing an inaccurate measurement value as an accurate measurement value. There was a case.

Japanese Patent Publication No.8-10208 International Publication No. 2004/017057 Pamphlet

  Therefore, the inventor of the present invention has come to the present invention as a result of intensive studies to investigate the cause of such a problem and solve such a problem.

  That is, an object of the present invention is to provide a biosensor capable of performing accurate measurement by detecting whether the amount of blood or the like introduced to the reaction part is an amount necessary for accurate measurement. To do.

The biosensor of the present invention includes a substrate made of an insulator, a measurement working electrode provided on the substrate, and a measurement counter electrode provided on the substrate at a predetermined interval from the measurement working electrode. A reaction portion provided on the working electrode for measurement and the counter electrode for measurement, and a supply port for introducing a sample to the reaction portion, and the reaction portion is attached to a measurement display, In the biosensor that measures the amount of the substrate component in the sample by reacting with the sample introduced from the supply port, the substrate is disposed on the opposite side of the supply port with respect to the measurement working electrode and the measurement counter electrode. A detection working electrode provided on the substrate, and a detection counter electrode provided on the substrate at a predetermined interval from the detection working electrode , wherein the detection working electrode and the detection counter electrode are: The reaction section is introduced from the supply port. By sensing a current value in which the generated between the detecting working electrodes and the detection counter electrode when in response to analyte, based on the current value generated between the working electrode and the detection counter-electrode said detectable, wherein the amount of the introduced sample is provided so as to determine the control means of the measuring indicator whether it is above a certain threshold value is a predetermined amount necessary for the measurement.

Furthermore, the biosensor of the present invention is characterized in that, in the biosensor, the reaction part contacts the detection working electrode and the detection counter electrode.

Furthermore, in the biosensor of the present invention, in the biosensor , the measurement working electrode and the measurement counter electrode are disposed between the detection working electrode and the detection counter electrode, and the detection working electrode and the detection working electrode are arranged. The counter electrode is provided so as not to contact the measurement working electrode and the measurement counter electrode .

In the biosensor of the present invention, the tip of the detection working electrode is disposed in a substantially semicircular cutout provided on the opposite side of the supply port in the measurement working electrode. The tip of the counter electrode for detection is arranged in a substantially semicircular cutout provided on the opposite side of the supply port in the counter electrode for measurement .

According to the biosensor of the present invention, the amount of the sample introduced from the supply port can be detected by the detection working electrode and the detection counter electrode. For this reason, it can be recognized whether the amount of the sample is an amount necessary for accurate measurement. Moreover, since the detection working electrode and the detection counter electrode are provided exclusively for detection, the detection working electrode and the detection counter electrode can be accurately detected, or a circuit or program dedicated to detection is formed. By doing so, accurate and stable detection can be performed. Further, since the detection working electrode and the detection counter electrode dedicated to detection are provided , the measurement working electrode and the measurement counter electrode are arranged between the detection working electrode and the detection counter electrode. Thus, it is possible to detect whether or not the amount of the specimen is an amount necessary for measurement by the measurement working electrode and the measurement counter electrode.

  Next, the biosensor according to the present invention will be described in detail based on the drawings. 1 and 2, reference numeral 10 denotes a biosensor of the present invention.

The biosensor 10 of the present invention includes a substrate 12 made of an insulator, a measurement working electrode 14 provided on the substrate 12, and a measurement working electrode 14 provided on the substrate 12 with a predetermined interval. A counter electrode 16, a measurement working electrode 14, a reaction part 18 provided on the measurement counter electrode 16, and a supply port 20 for introducing blood (specimen) to the reaction part 18, are supplied by the reaction part 18. It is a biosensor that measures blood glucose level (substrate component amount) in blood by reacting with blood introduced from the mouth 20. In this biosensor 10, the detection working electrode 22 provided on the substrate 12 and the detection working electrode on the substrate 12 on the side opposite to the supply port 20 with respect to the measurement working electrode 14 and the measurement counter electrode 16. 22 and a counter electrode for detection 24 provided at a predetermined interval, and discriminates whether the amount of blood introduced by the detection working electrode 22 and the counter electrode for detection 24 is a predetermined amount necessary for measurement Is configured to do.

The insulator constituting the substrate 12 is, for example, polyethylene terephthalate (PET), polyethylene naphthalate, a polyester resin sheet such as a biodegradable polyester resin composed of an aliphatic unit and an aromatic unit, more heat resistance, chemical resistance, Examples thereof include a polyamideimide sheet having excellent strength, a plastic sheet such as a polyimide film sheet, and an inorganic substrate such as ceramic.

  The measuring working electrode 14 and the measuring counter electrode 16 are each formed in a substantially semicircular shape, and both form a substantially circular shape. The measuring working electrode 14 and the measuring counter electrode 16 are formed on the electrically insulating substrate 12 by a good conductor such as platinum, gold, palladium, indium-tin oxide, or the like. As a forming method, hot stamping can be considered. Vacuum deposition or sputtering is preferable because a fine electrode pattern can be formed with high accuracy. In the case of sputtering, it can be formed at once by masking the outside of the formation of both electrodes.

  The reaction unit 18 includes an oxidoreductase and an electron acceptor. For example, it is configured by applying and drying a liquid material containing an oxidoreductase and an electron acceptor. Examples of the oxidoreductase include glucose oxidase when measuring glucose. Glucose oxidase reacts with glucose to produce gluconic acid and hydrogen peroxide. Moreover, when measuring an alcohol value, alcohol oxidase or alcohol dehydrogenase is used. When measuring lactic acid, lactate oxidase or lactate dehydrogenase is used. When measuring uric acid, uricase is used. Generally, it is an inorganic or organic fine powdery compound that promotes oxidation-reduction of enzymes. For example, alkali metal ferricyanide (particularly potassium ferricyanide metal salt is preferable), ferrocene or an alkyl-substituted product thereof, p-benzoquinone, methylene blue, potassium β-naphthoquinone-4-sulfonate, phenazine methosulfate, 2,6- Examples include dichlorophenol-indophenol. Ferricyanide alkali metal salts and ferrocenes have a stable function as an electron transfer medium and are well soluble in aqueous solvents such as water, alcohols, or mixed solvents thereof, and thus effectively function as electron acceptors.

  As shown in FIG. 2, the supply port 20 includes a leading edge 31 of a cover 28 provided on the substrate 12 via a spacer 26 and a leading edge 33 of the substrate 12. That is, the supply port 20 is configured by a gap generated between the leading edge 31 and the leading edge 33 by the spacer 26. The blood introduced from the supply port 20 can reach the tip edge 35 of the spacer 26 by capillary action if the amount is sufficient.

Detecting working electrode 22 and the detection counter electrode 24, as shown in FIG. 2, it has a contact with the measurement the working electrode 14 and the measuring counter electrode 16 while sandwiching the measurement the working electrode 14 and the measuring counter electrode 16 It is provided in the form state. The tip of the detection working electrode 22 enters a substantially semicircular cutout 23 provided on the opposite side of the supply port 20 in the measurement working electrode 14, and the tip of the detection counter electrode 24 is the measurement counter electrode. 16 , it enters a substantially semicircular cutout 25 provided on the side opposite to the supply port 20. Accordingly, the blood introduced from the supply port 20 can be configured to reach the detection working electrode 22 and the detection counter electrode 24 after passing through the measurement working electrode 14 and the measurement counter electrode 16, and to detect the blood. The tips of the working electrode 22 and the counter electrode for detection 24 can be made as long as possible to perform reliable detection.

The reaction part 18 is in contact with the detection working electrode 22 and the detection counter electrode 24, and not when the blood directly contacts the detection working electrode 22 and the detection counter electrode 24. Is configured to detect the amount of blood introduced by detecting the current value between the detection working electrode 22 and the detection counter electrode 24 when it reacts with blood introduced from the supply port 20. The materials of the detection working electrode 22 and the detection counter electrode 24 are the same as the materials of the measurement working electrode 14 and the measurement counter electrode 16 described above.

  As shown in FIG. 3A, the biosensor 10 is provided with a measurement working electrode 14, a measurement counter electrode 16, a detection working electrode 22, and a detection counter electrode 24 on a substrate 12. ), The reaction part 18 is applied on the measurement working electrode 14 and the measurement counter electrode 16, the detection working electrode 22 and the detection counter electrode 24, and covered with a cover 28 via a spacer 26. It is formed.

In addition, when measuring the blood glucose level, such a biosensor 10 is inserted into the sensor mounting opening of the measurement display 30 so that it is integrated with the measuring working electrode 14 as shown in FIG. The working electrode terminal 32 is connected to the control means 36 via the switch 34 and the like, and the measuring counter electrode terminal 38 integrated with the measuring counter electrode 16 is connected to the control means 36 via the switch 40 and the like, and the detection working electrode 22 is connected to the control means 36 via a switch 44 or the like, and the detection counter electrode terminal 46 integral with the detection counter electrode 24 is connected to the control means 36 via a switch 48 or the like. Is done.

  The operation of measuring the blood glucose level using the biosensor 10 having such a configuration will be described below. The blood glucose level measurer first inserts the biosensor 10 into the sensor mounting opening of the measurement display 30 and drops the blood that has been pierced with a fingertip or the like onto the supply port 20 of the biosensor 10. The blood spotted on the supply port 20 flows in the gap between the substrate 12 and the cover 28 along the measuring working electrode 14 and the measuring counter electrode 16 toward the leading edge 35 of the spacer 26 by capillary action.

At this time, when the switches 44 and 48 are turned on and the switches 34 and 40 are turned off, and the amount of blood spotted on the supply port 20 is sufficient to accurately measure the blood sugar level, The blood also reaches and reacts near the end opposite to the supply port 20 in the reaction unit 18, or when the reaction is sufficiently performed over the entire reaction unit 18, or the detection working electrode 22 and the detection counter electrode When electrons are exchanged between 24, an electric current is generated between the detection working electrode 22 and the detection counter electrode 24. The control means 36 recognizes the current value generated between the detection working electrode 22 and the detection counter electrode 24. When the control means 36 recognizes that the current value is equal to or greater than a certain value (threshold value), the control means 36 determines that the amount of blood is sufficient to accurately measure the blood glucose level, and the switch 34 and In the state where 40 is turned on and the switches 44 and 48 are turned off, the measurement of the blood glucose level is started by the measurement working electrode 14 and the measurement counter electrode 16, and the measured blood glucose level is displayed on the display means. Thereby, the measurer can read the blood glucose level with the recognition that the measured value is accurate.

  On the other hand, when the amount of blood spotted on the supply port 20 is insufficient to accurately measure the blood glucose level, no current is generated between the detection working electrode 22 and the detection counter electrode 24. Measurement does not start. Thus, the measurer does not have a risk of erroneously reading an incorrect blood sugar level.

  As mentioned above, although one Embodiment of this invention was described, this invention can be implemented also in another aspect. For example, the biosensor 50 shown in FIG. 5 may be used. In this biosensor 50, the measurement counter electrode 16 is provided on the supply port 20 side, and the measurement working electrode 14 is provided on the side opposite to the supply port 20 with respect to the measurement counter electrode 16.

  Further, the present invention is not limited to the illustrated embodiment. For example, the reaction unit 18 is not limited to contact with the detection working electrode 22 and the detection counter electrode 24, but only with the measurement working electrode 14 and the measurement counter electrode 16, and in a narrower range than FIG. 2. It may be provided. In this case, the amount of blood can be detected by the reaction unit 18 reacting with blood and dissolving in the vicinity, or when the detection working electrode 22 and the detection counter electrode 24 are conducted. In addition, the technical scope of the present invention includes embodiments in which various improvements, modifications, and variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Moreover, you may implement with the form which substituted any invention specific matter to the other technique within the range which the same effect | action or effect produces.

  According to the biosensor of the present invention, it is possible to recognize whether or not the amount of the specimen is an amount necessary for accurate measurement. For this reason, it can be widely used for accurate measurement by a biosensor.

It is a front view of the biosensor of the present invention. It is a partially expanded front view of the biosensor of FIG. It is a figure which shows the assembly method of the biosensor of FIG. 1, The figure (a) is a front view before providing the reaction part, The figure (b) is a front view which shows the state which provides a spacer and a cover. It is a circuit diagram of the measurement indicator used for the biosensor of FIG. It is a front view which shows other embodiment of the biosensor of this invention.

Explanation of symbols

10, 50: Biosensor 12: Substrate 14: Measuring working electrode 16: Measuring counter electrode 18: Reaction unit 20: Supply port 22: Detection working electrode 24: Detection counter electrode 26: Spacer 28: Cover 30: Measurement display

Claims (2)

A substrate made of an insulator, a measurement working electrode provided on the substrate, a measurement counter electrode provided on the substrate at a predetermined interval from the measurement working electrode, the measurement working electrode, and A reaction section provided on the counter electrode for measurement, and a supply port for introducing the specimen to the reaction section,
In a biosensor that measures the amount of a substrate component in a sample by reacting the sample introduced from the supply port with the reaction unit attached to a measurement display ,
On the opposite side of the supply port to the measurement working electrode and the measurement counter electrode, the detection working electrode is provided on the substrate, and is provided on the substrate at a predetermined interval from the detection working electrode. A counter electrode for detection,
The detection working electrodes and the detection counter electrode, by sensing a current value in which the reaction portion is caused between the detecting working electrodes and the detection counter electrode when the response to the introduced sample from said supply port Based on the current value generated between the detection working electrode and the detection counter electrode, the measurement indicator displays whether the amount of the introduced sample is equal to or greater than a certain threshold which is a predetermined amount necessary for the measurement. So that it can be discriminated by the control means of
The reaction portion is in contact with the detection working electrode and the detection counter electrode;
The measurement working electrode and the measurement counter electrode are arranged between the detection working electrode and the detection counter electrode, and the detection working electrode and the detection counter electrode are connected to the measurement working electrode and the measurement counter electrode. Biosensor provided in a form that does not touch the surface . The tip of the detection working electrode is arranged in a substantially semi-circular cutout provided on the opposite side of the supply port in the measurement working electrode, and the tip of the detection counter electrode is opposite to the measurement counter electrode. The biosensor according to claim 1, wherein the biosensor is disposed in a substantially semicircular cutout provided on the opposite side of the electrode from the supply port .

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