Electrochemical Biosensor with Improved Accuracy

• US 20150083613A1
• Filed: 12/01/2014
• Published: 03/26/2015
• Est. Priority Date: 06/01/2012
• Status: Active Grant

• Current Assignee: i-SENS, Inc.
• Original Assignee: i-SENS, Inc.
• Inventors: LEE, Myeong Ho, KIM, Moon Hwan, LEE, Ung Ki, PARK, Han Be, JUNG, Sung-Kwon, NAM, Hakhyun, CHA, Geun Sig
• Granted Patent: US 9,753,004 B2
• Time in Patent Office: Days
• US Class Current: 205/782
• CPC Class Codes: C12Q 1/006 for glucose
• 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 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771
• CPC Class Codes: G01N 27/3277 being a redox reaction, e.g. detection by cyclic voltammetry voltammetry per se G01N27/42, G01N27/48
• CPC Class Codes: G01N 33/66 involving blood sugars, e.g. galactose

Abstract

The present invention relates to an electrochemical biosensor with improved hematocrit measurement accuracy for measuring blood glucose. According to the present invention, an electrochemical biosensor including a first electrode part for correcting a measured hematocrit value and a second electrode part for measuring a glucose concentration is effective in improving accuracy of a measured hematocrit value and in more improving accuracy of a measured blood glucose concentration using the measured hematocrit values for correction, because an insulation cover is made thinner than a working electrode and an auxiliary electrode, so that areas of a first working electrode and a first auxiliary electrode of the first electrode part exposed to a blood sample become equal; a distance between the first working electrode and the second working electrode becomes constant; and electrode areas are maintained constantly by the insulation cover even when a positioning error occurs during printing.

Claims

1. An electrochemical biosensor, comprising:

a lower substrate;

a first electrode part including a first working electrode and a first auxiliary electrode which are formed on the lower substrate;

a second electrode part including a second working electrode and a second auxiliary electrode which are formed on the lower substrate;

a reagent layer formed on the second working electrode or the second auxiliary electrode, the reagent layer including an electron transfer mediator;

an insulation cover having regions which correspond to first, second and third reaction units and are partitioned to have cavities, respectively, wherein the first reaction unit is positioned at the first working electrode, a second reaction unit is positioned at the first auxiliary electrode, and a third reaction unit is positioned at the second working electrode;

an intermediate substrate equipped with a microchannel sample cell part to successively guide a blood sample into the first electrode part and the second electrode part; and

an upper substrate,

wherein areas of and a distance between the first working electrode and the first auxiliary electrode exposed at the first reaction unit and the second reaction unit are constant by means of the insulation cover.

2. The electrochemical biosensor as set forth in claim 1, wherein the insulation cover covers at least one inclined edge of the first working electrode exposed at the first reaction unit, and at least one inclined edge of the first auxiliary electrode exposed at the second reaction unit.

3. The electrochemical biosensor as set forth in claim 1, wherein a thickness of the insulation cover is smaller than a thickness of the electrode.

4. The electrochemical biosensor as set forth in claim 1, wherein the insulation cover is printed with a hydrophobic insulation ink.

5. The electrochemical biosensor as set forth in claim 4, wherein the hydrophobic insulation ink is one selected from the group consisting of polyacryl-based, epoxy-based and ceramic-based inks.

6. The electrochemical biosensor as set forth in claim 1, wherein the first reaction unit positioned at the first working electrode and the second reaction unit positioned at the first auxiliary electrode are positioned on a line perpendicular to a longitudinal direction along which blood flows into the microchannel sample cell part such that the first and the second reaction unit are overlapped at least in part.

7. The electrochemical biosensor as set forth in claim 1, wherein the first reaction unit positioned at the first working electrode and the second reaction unit positioned at the first auxiliary unit have the same shape.

8. The electrochemical biosensor as set forth in claim 1, wherein the first reaction unit positioned at the first working electrode and the second reaction unit positioned at the first auxiliary unit are positioned in a decalcomania form with respect to a central line of a longitudinal direction, on a line perpendicular to a longitudinal direction along which blood flows into the microchannel sample cell part.

9. The electrochemical biosensor as set forth in claim 1, wherein the first working electrode and the second working electrode are devoid of a reagent layer.

10. The electrochemical biosensor as set forth in claim 1, wherein the reagent layer further includes a redox enzyme.

11. The electrochemical biosensor as set forth in claim 1, wherein the first electrode part calculates hematocrit by measuring a conductivity of a blood sample.

12. The electrochemical biosensor as set forth in claim 1, wherein the second electrode part measures a current caused by a redox reaction of glucose in a blood sample.

13. The electrochemical biosensor as set forth in claim 1, wherein the first electrode part measures an electrical conductivity by applying an alternating current (AC) voltage.

14. The electrochemical biosensor as set forth in claim 1, wherein the second electrode part measures a current caused by a redox reaction of glucose by applying a direct current (DC) voltage.

15. The electrochemical biosensor as set forth in claim 1, wherein the first electrode or the second electrode further comprises a flow sensing electrode.

16. A method for precisely measuring a blood glucose concentration by applying a hematocrit value using the biosensor as set forth in claim 1, the method comprising:

introducing a blood sample into a microchannel sample cell part (step

     1);

calculating a hematocrit value by measuring an electrical conductivity of the blood sample at a first electrode part (step

     2);

calculating a glucose concentration by measuring a signal at a second electrode part (step

     3); and

correcting the glucose concentration calculated at the second electrode part by applying the hematocrit value calculated at the first electrode part (step

     4).