Concentration determination in a diffusion barrier layer

• US 8,317,988 B2
• Filed: 04/11/2007
• Issued: 11/27/2012
• Est. Priority Date: 10/12/2004
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Wu, Huan-Ping
• Primary Examiner(s): Noguerola, Alex
• Application Number:
  US11/734,251
• Publication Number:
  US 20070246357A1
• Time in Patent Office: 2,057 Days
• Field of Search: 20440301-40315, 205/777.5, 205/778, 205/792
• US Class Current: 204/403.14
• CPC Class Codes: B32B 2307/202 Conductive
• CPC Class Codes: B32B 38/18 Handling of layers or the laminate
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: C12Q 1/005 involving specific analytes or enzymes including groups of enzymes, e.g. oxydases; C12Q1/004 takes precedence
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: C12Q 1/6813 Hybridisation assays
• CPC Class Codes: C12Q 1/6825 Nucleic acid detection involving sensors
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• 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 27/3276 being a hybridisation with immobilised receptors using a FET type sensor G01N27/4145; concerning the hybridisation C12Q1/68
• 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 27/40 Semi-permeable membranes or partitions
• CPC Class Codes: G01N 33/5438 Electrodes

Abstract

The present invention relates to improved electrochemical biosensor strips and methods for determining the concentration of an analyte in a sample. By selectively measuring a measurable species residing in a diffusion barrier layer, to the substantial exclusion of the measurable species residing exterior to the diffusion barrier layer, measurement errors introduced by sample constituents, such as red blood cells, and manufacturing variances may be reduced.

Claims

1. An electrochemical system, for determining the concentration of an analyte in a sample, comprising:

a sensor, including;

a base;

a first electrode on the base, the first electrode having at least one first layer on a first conductor, the first conductor on the base,

where the first layer has an average initial thickness of less than 30 μ

m, and

where the first layer includes at least one binder forming a diffusion barrier layer, the diffusion barrier layer having an internal volume, and

where the binder includes a polymeric material that is at least partially water soluble; and

a second electrode; and

a measurement device,

the measurement device in electrical communication with the first electrode through the first conductor, and the measurement device in electrical communication with the second electrode through a second conductor,

where the measurement device applies a read pulse to the sensor, the read pulse having a duration of less than 5 seconds.

2. The electrochemical system of claim 1, where the first layer is a reagent layer including at least one of an oxidoreductase enzyme and a mediator.

3. The electrochemical system of claim 1, where the second electrode comprises the first layer on the second conductor, the second conductor on the base.

4. The electrochemical system of claim 3, where the duration of the read pulse is less than 3 seconds.

5. The electrochemical system of claim 3, where the duration of the read pulse is from 0.05 second to 2.8 seconds.

6. The electrochemical system of claim 3, where the duration of the read pulse is from 0.1 second to 1.5 seconds.

7. The electrochemical system of claim 3, where at least 50% of the average initial thickness of the first layer remains on the conductor 5 seconds after a sample is introduced to the sensor.

8. The electrochemical system of claim 1, where the duration of the read pulse is less than 3 seconds.

9. The electrochemical system of claim 8, where the average initial thickness of the first layer is at least 1 μ

m.

10. The electrochemical system of claim 8, where the average initial thickness of the first layer is from 5 to 25 μ

m.

11. The electrochemical system of claim 8, where at least 50% of the average initial thickness of the first layer remains on the conductor 5 seconds after a sample is introduced to the sensor.

12. The electrochemical system of claim 1, where the duration of the read pulse is from 0.05 second to 2.8 seconds.

13. The electrochemical system of claim 1, where the duration of the read pulse is from 0.1 second to 1.5 seconds.

14. The electrochemical system of claim 8, where the average initial thickness of the first layer is at least 1 μ

m.

15. The electrochemical system of claim 1, where the average initial thickness of the first layer is from 5 to 25 μ

m.

16. The electrochemical system of claim 1, where at least 50% of the average initial thickness of the first layer remains on the conductor 5 seconds after a sample is introduced to the sensor.

17. The electrochemical system of claim 8, where from 70% to 80% of the average initial thickness of the first layer remains on the conductor 5 seconds after a sample is introduced to the sensor.

18. The electrochemical system of claim 1, where the first electrode further comprises a reagent layer on the first layer,

the reagent layer including at least one of an oxidoreductase enzyme and a mediator;

where the first layer is a distinct layer that does not include a substantial amount of at least one of an oxidoreductase and a mediator.

19. The electrochemical system of claim 1, where the polymeric material includes at least one of poly(ethylene oxide), carboxy methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, derivatives thereof, and combinations thereof.

20. The electrochemical system of claim 1, further comprising a sample in electrical communication with the first and second electrodes.

21. The electrochemical system of claim 20, where the read pulse substantially detects a measurable species within the diffusion barrier layer, and where the read pulse substantially does not detect the measurable species external to the diffusion barrier layer.

22. The electrochemical system of claim 1, where, for a plurality of sensors, at least 50% of the average initial thickness of the first layer remains on the conductor 5 seconds after a sample is introduced to the sensor.