Sensor arrays for detecting analytes in fluids

• US 20040033165A1
• Filed: 04/07/2003
• Published: 02/19/2004
• Est. Priority Date: 03/27/1995
• Status: Abandoned Application

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Freund, Michael S., Lewis, Nathan S.
• Application Number:
  US10/409,449
• Publication Number:
  US 20040033165A1
• Time in Patent Office: Days
• US Class Current: 422/82.02
• 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
• CPC Class Codes: G01N 33/497 of gaseous biological material, e.g. breath
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

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. A sensor array for detecting an analyte in a fluid for use in conjunction with an electrical measuring apparatus, said array comprising at least first and second chemical sensors each comprising:

at least first and second conductive leads suitable for electrical connection to the electrical measuring apparatus and electrically coupled to a chemically sensitive resistor comprising a plurality of alternating nonconductive regions comprising a nonconductive organic polymer and conductive regions comprising a conductive material compositionally different than said nonconductive organic polymer, said resistor providing

an electrical path between said conductive leads and through said regions,

a first electrical resistance between said conductive leads when said resistor is contacted with a first fluid comprising a chemical analyte at a first concentration, and

a second electrical resistance between said conductive leads when said resistor is contacted with a second fluid comprising said chemical analyte at a second different concentration,

the difference between said first electrical resistance and said second electrical resistance of said first chemical sensor being different from the difference between said first electrical resistance and said second electrical resistance of said second chemical sensor.

2. A sensor array according to claim 1, wherein said plurality of nonconductive regions of said first chemical sensor is different from said plurality of nonconductive regions of said second chemical sensor.

3. A sensor array according to claim 1, wherein said nonconductive organic polymer of said first chemical sensor is qualitatively different from said nonconductive organic polymer of said second chemical sensor.

4. A sensor array according to claim 1, wherein said conductive material is an inorganic conductor.

5. An system for detecting an analyte in a fluid, said system comprising:

at least first and second chemical sensors each comprising at least first and second conductive leads electrically coupled to a chemically sensitive resistor comprising a plurality of alternating nonconductive regions comprising a nonconductive organic polymer and conductive regions comprising a conductive material compositionally different than said nonconductive organic polymer, said resistor providing an electrical path between said conductive leads and through said regions, a first electrical resistance between said conductive leads when said resistor is contacted with a first fluid comprising a chemical analyte at a first concentration and a second different electrical resistance when said resistor is contacted with a second fluid comprising said chemical analyte at a second different concentration, the difference between said first electrical resistance and said second electrical resistance of said first chemical sensor being different from the difference between said first electrical resistance and said second electrical resistance of said second chemical sensor;

an electrical measuring device electrically connected to at least one of said conductive leads; and

a computer comprisng a resident algorithm;

said electrical measuring device being capable of detecting said first and said second electrical resistances in each said sensor and said computer capable of assembling said resistances into a sensor array response profile.

6. A system according to claim 5, wherein said plurality of nonconductive regions of said first chemical sensor is different from said plurality of nonconductive regions of said second chemical sensor.

7. A system according to claim 5, wherein said nonconductive organic polymer of said first chemical sensor is qualitatively different from said nonconductive organic polymer of said second chemical sensor.

8. A system according to claim 5, wherein said conductive material is an inorganic conductor.

9. A method for detecting the presence of an analyte in a fluid, said method comprising:

resistively sensing the presence of an analyte in a fluid with a chemical sensor comprising first and second conductive leads electrically coupled to a chemically sensitive resistor comprising a plurality of alternating nonconductive regions comprising a nonconductive organic polymer and conductive regions comprising a conductive material compositionally different than said nonconductive organic polymer, said resistor providing an electrical path between said conductive leads and through said regions, a first resistance between said conductive elements when said resistor is contacted with a first fluid comprising a chemical analyte at a first concentration and a second different resistance when said resistor is contacted with a second fluid comprising said chemical analyte at a second different concentration.

10. A method according to claim 9, wherein said plurality of nonconductive regions of said first chemical sensor is different from said plurality of nonconductive regions of said second chemical sensor.

11. A method according to claim 9, wherein said nonconductive organic polymer of said first chemical sensor is qualitatively different from said nonconductive organic polymer of said second chemical sensor.

12. A method according to claim 9, wherein said conductive material is an inorganic conductor.

13. A method according to claim 9, said first and said resistance each being a resistance over time.