Method for measuring temperature of biological sample, measuring device, and biosensor system

• US 9,395,320 B2
• Filed: 09/05/2014
• Issued: 07/19/2016
• Est. Priority Date: 01/30/2009
• Status: Active Grant

• Current Assignee: PHC Holdings Corporation
• Original Assignee: Panasonic Healthcare Holdings Co., Ltd.
• Inventors: Fujiwara, Masaki
• Primary Examiner(s): Wallenhorst, Maureen
• Application Number:
  US14/478,095
• Publication Number:
  US 20150096904A1
• Time in Patent Office: 683 Days
• Field of Search: 436/63, 436/70, 436/95, 436/147, 436/149, 436/150, 422/68.1, 422/73, 422/82.01, 422/82.02, 422/82.12, 422/503, 435/14, 435/29, 204/403.01, 205/792
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: B01L 2200/147 Employing temperature sensors
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 3/502 with fluid transport, e.g. in multi-compartment structures centrifugal-type cuvettes G01N21/07; analysis by separation into components G01N30/00; automatic analysers G01N35/00
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: G01K 7/00 Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat giving results other than momentary value of temperature G01K3/00 ; Power supply therefor, e.g. using thermoelectric elements
• CPC Class Codes: G01N 27/26 by investigating electrochemical variables; by using electrolysis or electrophoresis
• CPC Class Codes: G01N 27/28 Electrolytic cell components
• CPC Class Codes: G01N 27/327 Biochemical electrodes , e.g. electrical or mechanical details for in vitro measurements
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52
• CPC Class Codes: G01N 27/3273 Devices therefor, e.g. test element readers, circuitry details not specific to biochemical electrodes G01N33/4875
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771
• CPC Class Codes: G01N 27/416 Systems G01N27/27 takes precedence
• CPC Class Codes: Y10T 436/144444 Glucose

Abstract

The concentration measurement method includes: introducing a predetermined amount of the biological sample into the capillary; measuring a temperature of the biological sample by applying a first voltage to the electrode unit when the temperature of the biological sample is measured, the first voltage allowing the temperature measurement to be less affected by increase and reduction in an amount of the analyte contained in the biological sample; measuring the concentration of the analyte contained in the biological sample by applying a second voltage to the electrode unit; measuring an environmental temperature in a surrounding of the biological sample; and correcting the concentration of the measured analyte based on the measured temperature of the biological sample and the measured environmental temperature.

Claims

1. A concentration measurement method of measuring a concentration of an analyte contained in a biological sample in a sensor chip including (i) an electrode unit including at least a working electrode and a counter electrode, the electrode unit including a reagent containing an electrolyte, and (ii) a capillary allowing the biological sample to be introduced therein, the concentration measurement method comprising:

an introduction of introducing a predetermined amount of the biological sample into the capillary;

a first temperature measurement of measuring a temperature of the biological sample by applying a first voltage to the electrode unit when the temperature of the biological sample is measured, the first voltage being higher than a voltage to be applied in measuring a concentration of glucose in the biological sample, which the first voltage allows the temperature measurement to be less affected by increase and reduction in an amount of the analyte contained in the biological sample;

a concentration measurement of measuring the concentration of the analyte contained in the biological sample by applying a second voltage to the electrode unit, the second voltage being applied in measuring the concentration of the glucose;

a second temperature measurement of measuring, using a thermistor, an environmental temperature in a surrounding of the biological sample; and

a correction of correcting the concentration of the analyte measured in the concentration measurement based on the temperature of the biological sample measured in the first temperature measurement and the environmental temperature measured in the second temperature measurement.

2. The concentration measurement method according to claim 1,

wherein the first temperature measurement includes measuring the temperature of the biological sample based on a magnitude of an electric current flowing through the electrode unit in contact with the biological sample.

3. The concentration measurement method according to claim 1,

wherein the correction includes (i) correcting the concentration of the analyte by comparing the temperature of the biological sample measured in the first temperature measurement with the environmental temperature measured in the second temperature measurement and (ii) selectively using data of the temperature of the biological sample measured in the first temperature measurement and the environmental temperature measured in the second temperature measurement.

4. The concentration measurement method according to claim 3,

wherein the correction includes (i) correcting the concentration of the analyte by comparing the temperature of the biological sample measured in the first temperature measurement with the environmental temperature measured in the second temperature measurement and (ii) selectively using the data of the temperature of the biological sample measured in the first temperature measurement and the environmental temperature measured in the second temperature measurement based on whether a difference between the temperature of the biological sample measured in the first temperature measurement and the environmental temperature measured in the second temperature measurement is within a predetermined range determined by a threshold.

5. The concentration measurement method according to claim 1,

wherein the correction includes correcting the concentration of the analyte contained in the biological sample based on a result obtained by executing a calculation for a coefficient, a datum obtained from the temperature of the biological sample measured in the first temperature measurement, and a datum obtained from the environmental temperature measured in the second temperature measurement, the coefficient being determined according to a difference between the data of the temperature of the biological sample measured in the first temperature measurement and the environmental temperature measured in the second temperature measurement.

6. The concentration measurement method according to claim 1,

wherein the analyte measured in the concentration measurement includes at least one of glucose, hematocrit and a reducing substance.

7. The concentration measurement method according to claim 6,

wherein the concentration measurement includes measuring the concentration of each of glucose, hematocrit and a reducing substance in the biological sample, and wherein the correction includes correcting the concentration of glucose measured in the concentration measurement based on the concentration of hematocrit or reducing substance, the temperature of the biological sample measured in the first temperature measurement, and the environmental temperature measured in the second temperature measurement.

8. The concentration measurement method according to claim 1,

wherein the concentration measurement includes applying the second voltage to a measurement electrode that is separate from the working electrode and the counter electrode, and

the first temperature measurement or the second temperature measurement is executed independently from the concentration measurement.

9. The concentration measurement method according to claim 8,

wherein an order and a timing of the application of the first voltage in the first temperature measurement is arbitrarily determined with respect to the application of the second voltage in the concentration measurement.

10. The concentration measurement method according to claim 1,

wherein the first temperature measurement or the second temperature measurement is executed after the concentration measurement step is completed.

11. A biosensor system, comprising:

a sensor chip configured to measure a temperature of a biological sample, the sensor chip including a temperature electrode unit including a working electrode and a counter electrode, the working and counter electrodes including a reagent containing an electrolyte, the temperature electrode unit being configured to receive a predetermined voltage to be applied in measuring the temperature of the biological sample, the predetermined voltage being higher than a voltage to be applied in measuring a concentration of glucose in the biological sample, which the predetermined voltage allows the temperature measurement to be less affected by an analyte contained in the biological sample; and

a measuring device including a control circuit, a voltage application section, a first temperature measurement section, a second temperature measurement section, an analyte measurement section, and a concentration correction section, wherein

the control circuit is configured to control application of the predetermined voltage to the temperature electrode unit of the sensor chip for a predetermined period of time,

the voltage application section is configured to apply the predetermined voltage to the temperature electrode unit for the predetermined period of time under the control of the control circuit,

the first temperature measurement section is configured to measure, using the temperature electrode unit, the temperature of the biological sample,

the second temperature measurement section includes a thermistor, and the second temperature measurement section is configured to measure, using the thermistor, an environmental temperature in an inside, a surface, or a surrounding of the measuring device,

the analyte measurement section is configured to measure a concentration of the analyte based on a magnitude of an electric current to be generated in the biological sample as a result of an electrochemical reaction where the analyte contained in the biological sample serves as a substrate, and

the concentration correction section is configured to correct the concentration of the analyte contained in the biological sample based on the temperature of the biological sample measured by the first temperature measurement section and the environmental temperature measured by the second temperature measurement section.

12. The biosensor system according to claim 11,

wherein the concentration correction section is configured to (i) compare a temperature datum measured by the first temperature measurement section and a temperature datum measured by the second temperature measurement section and (ii) correct the analyte concentration with a selected one of the temperature datum measured by the first temperature measurement section and the temperature datum measured by the second temperature measurement section.

13. The biosensor system according to claim 11,

wherein the concentration correction section is configured to (i) determine a predetermined coefficient depending on a difference between a temperature datum measured by the first temperature measurement section and a temperature datum measured by the second temperature measurement section and (ii) correct the concentration of the analyte contained in the biological sample based on a result obtained by executing a calculation for the predetermined coefficient, the temperature datum measured by the first temperature measurement section, and the temperature datum measured by the second temperature measurement section.

14. The biosensor system according to claim 11,

wherein the first temperature measurement section is configured to measure the temperature of the biological sample based on a magnitude of an electric current flowing through the temperature electrode unit in contact with the biological sample.

15. The biosensor system according to claim 11, further comprising:

a comparison section configured to compare a difference between the temperature of the biological sample measured by the first temperature measurement section and the environmental temperature measured by the second temperature measurement section with a temperature threshold.

16. The biosensor system according to claim 15,

wherein concentration correction section is configured to correct the concentration of the analyte by selectively using data of the temperature of the biological sample measured by the first temperature measurement section and the environmental temperature measured by the second temperature measurement section, based on a result of comparison made by the comparison section.

17. The biosensor system according to claim 11,

wherein the voltage application section is configured to apply a direct-current voltage falling in a voltage range allowing a solvent in the biological sample to be electrolyzed.

18. The biosensor system according to claim 11,

wherein the analyte measured in the analyte measurement section is at least one of glucose, hematocrit and a reducing substance.

19. The biosensor system according to claim 18,

wherein the analyte measurement section measures the concentration of each of glucose, hematocrit and a reducing substance in the biological sample, and wherein the concentration correction section is configured to correct the concentration of glucose measured by the analyte measurement section based on the concentration of hematocrit or reducing substance, the temperature of the biological sample measured by the first temperature measurement section, and the environmental temperature measured by the second temperature measurement section.

20. The biosensor system according to claim 11,

wherein the voltage application section is configured to apply a first voltage when the first temperature measurement section measures the temperature of the biological sample and a second voltage when the analyte measurement section measures the concentration of the analyte, and

the first voltage is greater than the second voltage.