MICROSECOND RESPONSE ELECTROCHEMICAL SENSORS AND METHODS THEREOF

• US 20100213079A1
• Filed: 02/23/2010
• Published: 08/26/2010
• Est. Priority Date: 02/24/2009
• Status: Abandoned Application

• Current Assignee: Ultradian Diagnostics LLC
• Original Assignee: Ultradian Diagnostics LLC
• Inventors: WILLIS, John Patrick
• Application Number:
  US12/711,087
• Publication Number:
  US 20100213079A1
• Time in Patent Office: Days
• US Class Current: 205/775
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: C12Q 1/003 Functionalisation
• 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 33/5438 Electrodes

Abstract

A system for the measurement of analyte concentration includes an electrochemical cell having a working electrode coated with a protein layer and a diffusion limiting barrier covering the protein layer, and a counter electrode; a voltage source which provides a voltage between the working electrode and the counter electrode when electrically connected by a conductive medium; and a computing system which measures the dynamic voltage output to the counter electrode within a time period prior to a response from the working electrode and method for use is disclosed.

Claims

1. A system for the measurement of analyte concentration comprising:

an electrochemical cell comprising a working electrode coated with a protein layer and a diffusion limiting barrier covering the protein layer, and

a counter electrode;

a voltage source which provides a voltage between the working electrode and the counter electrode when electrically connected through a conductive medium; and

a computing system which measures the dynamic voltage output to the counter electrode within a time period prior to a response from the working electrode.

2. The system of claim 1 wherein the voltage source is a potentiostat.

3. The system of claim 1, wherein the counter electrode is in contact with a diffusion limiting barrier.

4. The system of claim 1, wherein a voltage waveform is applied between the counter electrode and working electrode.

5. The system of claim 1, further comprising a reference electrode.

6. The system of claim 1, wherein the time period prior to a working electrode response is less than about 200 microseconds.

7. The system of claim 4, wherein the application of the voltage waveform causes the output voltage of an operational amplifier of the potentiostat to slew each time a waveform is applied.

8. The system of claim 1, wherein the computing system measures the rate of change of the output voltage of the counter electrode between at least two voltage time points yielding a value proportional to analyte concentration at the working electrode.

9. The system of claim 3, wherein the counter electrode diffusion limiting barrier is the skin of a user.

10. The system of claim 1, wherein the diffusion limiting barrier comprises a polymeric material.

11. The system of claim 10, wherein the polymeric material comprises a polyurethane.

12. The system of claim 1, wherein the protein layer comprises an enzyme, antigen, antibody, fragment of RNA, or fragment of DNA.

13. The system of claim 1, wherein the conductive medium comprises living tissue.

14. The system of claim 13, wherein the living tissue comprises subcutaneous tissue.

15. An electronic circuit for measuring voltage or charge of a counter electrode within a time period prior to a working electrode response comprising a voltage waveform source between a counter and working electrode and an analog to digital converter capable of sampling the voltages at a rate sufficient to yield two or more voltage measurements within a time period between 0 and a time point defined by tV_max.

16. A method for determining a concentration of at least one analyte, the method comprising:

providing an electrochemical cell comprising a working electrode coated with a protein layer and a diffusion limiting barrier covering the protein layer, and a counter electrode;

a voltage source which provides a voltage between the working electrode and the counter electrode; and

a computing system which measures the dynamic voltage output to the counter electrode;

positioning the working electrode and the counter electrode in an electrically conductive medium;

applying voltage from the voltage source to the working electrode and the counter electrode;

detecting the applied voltage to the counter electrode prior to the working electrode response; and

determining a concentration of at least one analyte.

17. The method of claim 16, wherein determining a concentration of at least one analyte is based on the rate of change of the voltage supplied to the counter electrode, V_c, V_min, tV_min, 1/tV_min, V_max, tV_max, 1/tV_max, RC, 1/RC or V_f.

18. The method of claim 16, wherein detecting the applied voltage to the counter electrode prior to the working electrode response is within less than about 200 microseconds.

19. The method of claim 16, wherein positioning the working electrode and the counter electrode in an electrically conductive medium comprises implanting the working electrode beneath the skin surface of a user and contacting the counter electrode with the outer skin surface of the user.

20. The method of claim 16, wherein applying voltage from the voltage source comprises applying a voltage waveform.