Sensors for detecting analytes in fluids

• US 5,911,872 A
• Filed: 10/14/1997
• Issued: 06/15/1999
• Est. Priority Date: 08/14/1996
• Status: Expired due to Term

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Severin, Erik, Lewis, Nathan S.
• Primary Examiner(s): Bell, Bruce F.
• Application Number:
  US08/949,730
• Time in Patent Office: 609 Days
• Field of Search: 422/98, 422/82.02, 422/82.09, 422/82.12, 422/68, 422/69, 205/787, 205/782.5, 205/775, 436/150, 204/406, 204/415, 204/418, 73/23.2, 73/23.31, 73/23.34, 73/335.05, 324/691, 324/693, 338/13, 338/14, 338/7
• US Class Current: 205/787
• CPC Class Codes: G01N 27/126 comprising organic polymers
• CPC Class Codes: G01N 33/0031 comprising two or more sensors, e.g. a sensor array

Abstract

Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

Claims

1. An array of sensors for detecting an analyte in a fluid, wherein each of said sensors comprise a chemically sensitive resistor electrically connected to an electrical measuring apparatus and being in thermal communication with a temperature control apparatus, said chemically sensitive resistor comprising:

a plurality of alternating nonconductive regions comprising a nonconductive organic material and conductive regions comprising a conductive material compositionally different than said nonconductive organic material wherein said resistor provides;

an electrical path through said alternating regions of nonconductive organic material and said conductive material; and

an electrical resistance R_m at temperature T_m when contacted with a fluid comprising said analyte, where m is an integer greater than 1; and

R_m in at least one resistor is different from R_m in at least one other resistor.

2. An array of sensors according to claim 1, wherein said conductive material is an inorganic conductor.

3. An array of sensors according to claim 2, wherein said inorganic conductor is a member selected from the group consisting of Ag, Au, Cu, Pt and AuCu.

4. An array of sensors according to claim 3, wherein said inorganic conductor is Au.

5. An array of sensors according to claim 1, wherein said conductive material is an organic conductor.

6. An array of sensors according to claim 1, wherein said nonconductive organic material in one of said chemically sensitive resistors is different from said nonconductive organic material in at least one other chemically sensitive resistor.

7. An array of sensors according to claim 1, wherein said conductive material in one chemically sensitive resistor is different from said conductive material in at least one other chemically sensitive resistor.

8. An array of sensors according to claim 1, wherein at least two of said chemically sensitive resistors are compositionally the same.

9. An array of sensors for detecting an analyte in a fluid, wherein each of said sensors comprise a chemically sensitive resistor electrically connected to an electrical measuring apparatus, said chemically sensitive resistor comprising:

a plurality of alternating nonconductive regions comprising a nonconductive organic material and conductive regions comprising a conductive material compositionally different than said nonconductive organic material, wherein said resistor provides;

an electrical path through said alternating regions of nonconductive organic material and said conductive material;

an electrical resistance in at least one resistor which is different from said electrical resistance in at least one other resistor; and

an electrical impedance Z_m at frequency ω

_m when contacted with a fluid comprising said analyte, where m is an integer greater than 1 and ω

_m does not equal 0.

10. An array of sensors according to claim 9, wherein said conductive material is an inorganic conductor.

11. An array of sensors according to claim 10, wherein said inorganic conductor is a member selected from the group consisting of Ag, Au, Cu, Pt and AuCu.

12. An array of sensors according to claim 11, wherein said inorganic conductor is Au.

13. An array of sensors according to claim 9, wherein said conductive material is an organic conductor.

14. An array of sensors according to claim 9, wherein said nonconductive organic material in one of said chemically sensitive resistors is different from said nonconductive organic material in at least one other chemically sensitive resistor.

15. An array of sensors according to claim 9, wherein said conductive material in one chemically sensitive resistor is different from said conductive material in at least one other chemically sensitive resistor.

16. An array of sensors according to claim 9, wherein at least two of said chemically sensitive resistors are compositionally the same.

17. An array of sensors for detecting an analyte in a fluid, wherein each of said sensors comprise a chemically sensitive resistor electrically connected to an electrical measuring apparatus and being in thermal communication with a temperature control apparatus, said chemically sensitive resistor comprising:

a plurality of alternative nonconductive regions comprising a nonconductive organic material and conductive regions comprising a conductive material compositionally different than said nonconductive organic material, wherein said resistor provides;

an electrical path through said alternating regions of nonconductive organic material and said conductive material;

an electrical resistance in at least one resistor which is different from said electrical resistance in at least one other resistor; and

an electrical impedance Z_m,n at frequency ω

_m and temperature T_n when contacted with a fluid comprising said analyte, where m and/or n is an integer greater than 1.

18. An array of sensors according to claim 17, wherein m and n are integers greater than 1.

19. An array of sensors according to claim 17, wherein said conductive material is an inorganic conductor.

20. An array of sensors according to claim 19, wherein said inorganic conductor is a member selected from the group consisting of Ag, Au, Cu, Pt and AuCu.

21. An array of sensors according to claim 20, wherein said inorganic conductor is Au.

22. An array of sensors according to claim 17, wherein said conductive material is an organic conductor.

23. An array of sensors according to claim 17, wherein said nonconductive organic material in one of said chemically sensitive resistor is different from said nonconductive organic material in at least one other chemically sensitive resistor.

24. An array of sensors according to claim 17, wherein said conductive material in one chemically sensitive resistor is different from said conductive material in at least one other chemically sensitive resistor.

25. An array of sensors according to claim 17, wherein at least two of said chemically sensitive resistors are compositionally the same.

26. A method for detecting an analyte in a fluid, said method comprising:

contacting a sensor array with a fluid comprising said analyte, wherein each of said sensors comprise a chemically sensitive resistor electrically connected to an electrical measuring apparatus and being in thermal communication with a temperature control apparatus, where said chemically sensitive resistor comprises a plurality of alternating nonconductive regions comprising nonconductive organic material and conductive regions comprising a conductive material compositionally different than said nonconductive organic material and provides,

an electrical path through said alternating regions of nonconductive organic material and said conductive material, and

measuring the electrical resistance R_m at temperature T_m where m is an integer greater than 1; and

R_m in at least one resistor is different from R_m in at least one other resistor;

thereby detecting the presence or absence of said analyte in said fluid.

27. A method for detecting an analyte in a fluid according to claim 26, wherein said conductive material is an inorganic conductor.

28. A method for detecting an analyte in a fluid, said method comprising:

contacting a sensor array with a fluid comprising said analyte, wherein each of said sensors comprise a chemically sensitive resistor electrically connected to an electrical measuring apparatus, wherein said chemically sensitive resistor comprises a plurality of alternating nonconductive regions comprising nonconductive organic material and conductive regions comprising a conductive material compositionally different than said nonconductive organic material and provides an electrical path through said alternating regions of nonconductive organic material and said conductive material;

an electrical resistance in at least one resistor which is different from said electrical resistance in at least one other resistor; and

measuring the electrical impedance Z_m at frequency ω

_m, where m is an integer greater than 1 and ω

_m does not equal 0.

29. A method for detecting an analyte in a fluid according to claim 28, wherein said conductive material is an inorganic conductor.

30. A method for detecting an analyte in a fluid, said method comprising:

contacting a sensor array with a fluid comprising said chemical analyte, said sensor comprising a chemically sensitive resistor electrically connected to an electrical measuring apparatus and being in thermal communication with a temperature control apparatus, wherein said chemically sensitive resistor comprises a plurality of alternating conductive regions comprising nonconductive organic material and conductive regions comprising a conductive material compositionally different than said nonconductive organic material and provides an electrical path through said alternating regions of nonconductive organic material and said conductive material;

an electrical resistance in at least one resistor which is different from said electrical resistance in at least one other resistor; and

measuring the electrical impedance Z_m,n at frequency ω

_m and temperature T_n, where m and/or n is an integer greater than 1, wherein said electrical impedance Z_m,n at frequency ω

_m and at temperature T_n is indicative of the presence or absence of said analyte in said fluid.

31. A method for detecting an analyte in a fluid according to claim 30, wherein said conductive material is an inorganic conductor.