Breath-based sensors for non-invasive molecular detection

• US 20060130557A1
• Filed: 12/16/2005
• Published: 06/22/2006
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: University of Iowa Research Foundation
• Original Assignee: University of Iowa Research Foundation
• Inventors: Haverhals, Luke M., Leddy, Johna
• Granted Patent: US 7,421,882 B2
• Time in Patent Office: Days
• US Class Current: 73/23.300
• CPC Class Codes: G01N 33/497 of gaseous biological material, e.g. breath
• CPC Class Codes: G01N 33/4972 Determining alcohol content for vehicle safety devices B60K28/06
• CPC Class Codes: H01M 2250/00 Fuel cells for particular applications; Specific features of fuel cell system
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/1023 having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: H01M 8/1039 halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y10S 436/90 Breath testing

Abstract

A method of diagnosing the health of an individual by collecting a breath sample from the individual and measuring the amount of each of a plurality of analytes in the sample. The amount of each analytes is measured by fitting a time response curve of a sample-evaluation fuel cell in which the fuel cell sample electrode is contacted with the sample with the analysis based on a function of standard time response curves for an equivalent fuel cell configuration obtained separately for each of the analytes on a fuel cell with equivalent construction as sample-evaluation fuel cell. Each of the plurality of analytes is generally indicative of an aspect of the individual'"'"'s health. Suitable analytes include, for example, inorganic compounds as well as compositions that exhibit negative reduction reactions at least for a portion of the time response curve. In particular, acetone exhibits a negative potential/current peak when it is an analyte in a fuel cell in an sample electrode with a counter electrode exposed to oxygen, which may or may not be introduced in the form of air. Various forms of analysis to estimate acetone concentrations in the breath can be used.

Claims

1. A method for the estimation of acetone concentration in a person'"'"'s breath, the method comprising fitting a time response curve of a sample-evaluation fuel cell wherein a sample electrode of the fuel cell is exposed to a breath sample and a counter electrode of the fuel cell is exposed to O₂, wherein the fitting is performed through the de-convolution of the sample time response curve in comparison of the sample time response curve with the time response curve of standard aqueous acetone solutions.

2. The method of claim 1 wherein standard acetone aqueous solution response curves are compared with the sample response curve to obtain the estimation of acetone concentration in the person'"'"'s breath.

3. The method of claim 2 wherein a weighting vector is used to weight different time regions differently.

4. The method of claim 1 wherein the sample time response curve comprises a negative peak, a depth of the negative peak being used in the estimation of acetone concentration in an individual'"'"'s breath by comparing the depth of the negative peak with standard depths evaluated with standard aqueous acetone solutions.

5. The method of claim 1 wherein the sample time response curve comprises a negative peak, an area of the negative peak being used in the estimation of acetone concentration in an individual'"'"'s breath by comparing the area of the negative peak with standard areas evaluated with standard aqueous acetone solutions.

6. The method of claim 1 further comprising using the fitting to evaluate at least one other volatile organic composition within the breath sample.

7. The method of claim 1 wherein the evaluation is performed with a portable breathalyzer comprising the sample-evaluation fuel cell and a microprocessor.

8. A method for evaluating the insulin state of an individual comprising estimating the concentration of acetone in a person'"'"'s blood stream from an estimate of acetone concentration within the breath sample obtained using the method of claim 1.

9. A method for diagnosing the health of an individual, the method comprising measuring the amount of a plurality of analytes in a breath sample from an individual by fitting a time response curve of a sample-evaluation fuel cell with at least one of the analytes having a negative potential peak in the time response curve indicating a reduction process, wherein a sample electrode of the fuel cell is exposed to a breath sample and the counter electrode of the fuel cell is exposed to a selected reactant.

10. The method of claim 9 wherein an analyte having a negative potential peak in the time response curve is acetone.

11. The method of claim 9 wherein the measuring is performed with a portable breathalyzer comprising the sample-evaluation fuel cell and a microprocessor.

12. The method of claim 9 wherein the selected reactant comprises O₂.

13. A method for diagnosing the health of an individual, the method comprising measuring the amount of a plurality of analytes in a breath sample from an individual by fitting a time response curve of a sample-evaluation fuel cell with at least one of the analytes being an inorganic compound wherein a sample electrode of the fuel cell is exposed to a breath sample and the counter electrode of the fuel cell is exposed to a selected reactant.

14. The method of claim 13 wherein an inorganic analyte is NO or ammonia.

15. The method of claim 13 wherein the measuring is performed with a portable breathalyzer comprising the sample-evaluation fuel cell and a microprocessor.

16. The method of claim 13 wherein the selected reactant comprises O₂.

17. A system comprising:

a flow apparatus that is configured to operably receive a breath sample from an individual;

a fuel cell comprising a sample electrode operably coupled to the flow apparatus and a counter electrode exposed to O₂, wherein the sample transported within the flow system operably contacts the sample electrode; and

an analyzer that receives a signal related to the potential of the fuel cell and evaluates the amount of acetone from a time response of the fuel cell signal as a function of time based on a standard time response of the fuel cell with acetone.

18. The system of claim 17 further comprising a sample collector operably connected to the flow apparatus.

19. The system of claim 18 wherein the sample collector comprises a mouthpiece.

20. The system of claim 17 wherein the flow system comprises a pump that facilitates control of the flow through the flow apparatus.

21. The system of claim 17 wherein the fuel cell comprises an ionomer as an electrolyte.

22. The system of claim 21 wherein the ionomer comprises a perfluoronated, sulfonic acid polymer.

23. The system of claim 17 wherein the sample electrode comprises a porous, conductive carbon cloth or paper gas diffusion layer.

24. The system of claim 17 wherein the analyzer comprises a microprocessor.

25. The system of claim 17 wherein the system is a portable unit.

26. The system of claim 17 wherein the O₂ is within air.