Small volume in vitro analyte sensor and methods

• US 6,749,740 B2
• Filed: 12/28/2001
• Issued: 06/15/2004
• Est. Priority Date: 11/04/1999
• Status: Expired due to Term

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Therasense Incorporated (Abbott Laboratories Incorporated)
• Inventors: Krishnan, Rajesh, Liamos, Charles T., Jin, Robert Y., Plante, Phillip John, Feldman, Benjamin J., Funderburk, Jeffery V., Vivolo, Joseph A., Cloud, Michael S.
• Primary Examiner(s): Olsen, Kaj K.
• Application Number:
  US10/033,575
• Publication Number:
  US 20020053523A1
• Time in Patent Office: 900 Days
• Field of Search: 204/401, 204/403.02, 204/403.03, 204/403.04, 204/406, 205/777.5, 205/792, 324/691, 324/692, 324/693, 439/630, 439/909
• US Class Current: 205/792
• 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: Y10S 439/909 Medical use or attached to human body

Abstract

A small volume sensor, and methods of making, for determining the concentration of an analyte, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. The sensor includes a working electrode and a counter electrode, and can include an insertion monitoring trace to determine correct positioning of the sensor in a connector. In one embodiment, the sensor determines the concentration of the analyte by discharging an amount of charge into the sample, determining the time needed to discharge the charge, and determining the current used to electrolyze a portion of the analyte using the amount of charge and the amount of time.

Claims

1. An operative combination for use in measuring bioanalyte in a sample;

the combination comprising;

(a) a sensor strip;

the sensor strip comprising;

(i) a substrate having a first end, a second end opposite the first end, a first side edge extending between the first end and second end, and a second side edge, opposite the first side edge and extending between the first end and second end;

(A) the substrate first end sized for insertion into an electrical connector;

(ii) a sample chamber positioned between the first and second ends;

(iii) at least three electrodes on the substrate and in operative contact with the sample chamber, each of the electrodes including a separate electrode trace extending from the sample chamber and along a length of the substrate; and

(iv) an insertion monitor stripe on the substrate;

(b) an electrical connector in electrical communication with a meter, the electrical connector having a sensor strip receiving area sized for operative receipt of the first end of the substrate;

the electrical connector further comprising;

(i) a first contact structure comprising at least three contact leads, one each of which is positioned to engage one each of three of the at least three electrode traces of the sensor strip when the substrate is operatively positioned with the first end positioned in the sensor strip receiving area of the electrical connector;

(ii) a second contact structure comprising at least a first insertion lead and a second insertion lead, each of the first and second insertion leads being positioned to operatively engage the insertion monitor stripe when the first end is operatively positioned in the sensor strip receiving area;

(A) the first insertion lead being positioned with a portion thereof extending across the first side edge of the sensor strip substrate to engage the insertion monitor stripe when the first end is operatively positioned in the sensor strip receiving area of the electrical connector; and

,

(B) the second insertion lead being positioned with a portion thereof extending across the second side edge of the sensor strip substrate to engage the insertion monitor stripe when the first end is operatively positioned in the sensor strip receiving area of the electrical connector;

(c) the sensor strip being removably mounted to the electrical connector with the substrate first end received in the sensor strip receiving area.

2. An operative combination according to claim 1 wherein:

(a) the insertion monitor stripe extends across the substrate from the first side edge to the second side edge.

3. An operative combination according to claim 1 wherein:

(a) the substrate has a first end edge adjacent the first end; and

(b) each one of the at least three electrode traces terminates at the first end edge of the substrate first end.

4. A kit for use in measuring bioanalyte in a sample;

the kit comprising;

(a) a sensor strip;

the sensor strip comprising;

(i) a substrate having a first end, a second end opposite the first end, a first side edge extending between the first end and second end, and a second side edge, opposite the first side edge and extending between the first end and second end;

(A) the substrate first end sized for insertion into an electrical connector;

(ii) a sample chamber positioned between the first and second ends;

(iii) at least three electrodes on the substrate and in operative contact with the sample chamber, each of the electrodes including a separate electrode trace extending from the sample chamber of the substrate; and

(iv) an insertion monitor stripe on the substrate;

(b) an electrical connector having a sensor strip receiving area sized for operative receipt therein of the first end of the sensor strip substrate;

the electrical connector further comprising;

(i) a first contact structure comprising at least three contact leads, one each of which is positioned to engage one each of three of the at least three electrode traces of the sensor strip when the substrate is operatively positioned with the first end positioned in the sensor strip receiving area of the electrical connector;

(ii) second contact structure comprising at least a first insertion lead and a second insertion lead, each of the first and second insertion leads being positioned to operatively engage the insertion monitor stripe when the sensor strip first end is operatively positioned in the sensor strip receiving area;

(A) the first insertion lead being positioned with a portion thereof extending across the first side edge of the sensor strip substrate to engage the insertion monitor stripe when the first end is operatively positioned in the sensor strip receiving area of the electrical connector; and

,

(B) the second insertion lead being positioned with a portion thereof extending across the second side edge of the sensor strip substrate to engage the insertion monitor stripe when the first end is operatively positioned in the sensor strip receiving area of the electrical connector.

5. A kit according to claim 4 wherein:

(a) the insertion monitor stripe extends from the first side edge of the substrate to the second side edge of the substrate.

6. A kit according to claim 5 wherein:

(a) the sensor strip substrate has a first end edge adjacent the first end, the first end edge extending between the first side edge and the second side edge;

(b) each one of the at least three contact leads of the first contact structure is positioned to extend across the first end edge of the sensor strip substrate to engage one of the at least three electrode traces when the sensor strip substrate first end is operatively positioned in the sensor strip receiving area of the electrical connector.

7. A kit according to claim 5 wherein:

(a) the sample chamber includes a measurement zone having a volume of no more than 1 μ

l.

8. A kit according to claim 7 wherein:

(a) the sensor strip is a side-filling sensor strip.

9. A kit according to claim 5 wherein:

(a) the sensor strip is a tip-filling sensor strip.

10. A kit according to claim 5 wherein:

(a) at least one of the at least three electrodes of the sensor strip is a working electrode covered by a redox mediator.

11. A kit according to claim 10 wherein:

(a) the redox mediator comprises a transition metal complex of osmium.

12. A kit according to claim 11 wherein:

(a) a first one of the at least three electrodes of the sensor strip is positioned opposite to, and facing, a second one of the at least three electrodes of the sensor strip, with the sample chamber positioned therebetween.

13. A kit according to claim 12 wherein:

(a) the first one of the at least three electrodes is separated from the second one of the at least three electrodes by no more than 50 μ

m.

14. A kit according to claim 5 wherein:

(a) the at least three electrodes of the sensor strip are positioned coplanar with one another.

15. A kit according to claim 5 wherein:

(a) the sensor strip comprises first and second, non-conducting, base substrates;

(b) the sample chamber and the at least three electrodes are positioned between the first and second base substrates;

(i) one of the at least three electrodes being a reference electrode positioned on one of the first and second, non-conducting, substrates;

(A) the reference electrode comprising a conductive carbon electrode; and

(ii) a second one of the at least three electrodes is a first working electrode positioned on one of the first and second non-conducting substrates;

(A) the first working electrode comprising a conductive carbon electrode; and

(iii) a third one of the at least three electrodes is a second working electrode positioned on one of the first and second non-conducting substrates;

(A) said second working electrode comprising a conductive carbon electrode.

16. A kit according to claim 15 wherein:

(a) the electrical connector further comprises a portion of a system that includes a sensor meter having;

(i) a component to selectively provide at least one of potential and current to the first contact structure;

(ii) a processor to selectively determine analyte concentration from sensor signals received via the electrical connector; and

,

(iii) a display to selectively show results determined from the sensor signals.

17. A kit according to claim 15 wherein:

(a) the insertion monitor stripe is positioned on an opposite side of one of the non-conducting base substrates from the sample chamber.

18. A method of measuring bioanalyte in a sample;

said method comprising;

(a) measuring a bioanalyte concentration in a sample, which includes inserting a first end of a sensor strip into a sensor strip receiving area of a electrical connector;

the step of inserting including;

(i) contacting one each of at least three contact leads in the electrical connector with separate ones of at least three electrode traces on the sensor strip; and

(ii) contacting first and second insertion leads of the electrical connector with an insertion monitor stripe on the sensor strip;

(A) the step of inserting including positioning the sensor strip so that the first insertion lead extends across a first side edge of the sensor strip to engage the insertion monitor stripe; and

(B) the step of inserting including positioning the sensor strip so that the second insertion lead extends across a second side edge of the sensor strip to engage the insertion monitor strip, the second side edge being an edge opposite the first side edge.

19. A method according to claim 18 wherein:

(a) the step of inserting includes positioning the sensor strip so that each one of three contact leads in the electrical connector extends across a first end edge of the sensor strip, to engage a respective electrode trace;

(i) the first end edge extending between the first and second side edges.

20. A method according to claim 18 wherein:

(a) the step of inserting includes inserting a first end of a sensor strip which includes, in a portion of the sensor strip other than the first end, a sample chamber including blood therein.