Intelligent electro-optical sensor array and method for analyte detection

• US 20040106211A1
• Filed: 06/30/2003
• Published: 06/03/2004
• Est. Priority Date: 02/18/2000
• Status: Abandoned Application

• Current Assignee: Trustees of Tufts College
• Original Assignee: Trustees of Tufts College
• Inventors: White, Joel E., Kauer, John S.
• Application Number:
  US10/610,157
• Publication Number:
  US 20040106211A1
• Time in Patent Office: Days
• US Class Current: 436/169
• CPC Class Codes: G01N 2021/7786 Fluorescence
• CPC Class Codes: G01N 21/6428 Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" in vivo A61B5/00; immunoassay G01N33/53
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 21/85 Investigating moving fluids or granular solids

Abstract

The invention relates to a chemical sensor, sensing system and sensing method which provides for a multi-sensor, cross-reactive, sensor array having a rapid response time, dynamic modulation of sampling parameters, and real-time feedback control of sampling and detection conditions. The device and method provide for smart detection and discrimination of analytes in fluids through intelligent sampling, detection, and control algorithms. The invention further provides for a sensor array having discrete sensor elements dispersed on fluid-permeable, high surface area, porous, textured substrates. The innovative device and method exhibit high sensitivity, discrimination and detection capability for target analytes at ppb and sub ppm concentrations.

Claims

1. An optical sensor for detecting target analytes in a fluid, said sensor comprising:

a fluid-permeable, textured dye substrate having a high surface area and high surface area to volume ratio, said substrate having high open porosity, said substrate having high permeability to fluids; and

a dye compound dispersed on a plurality of internal and external surfaces within said textured dye substrate, said dye compound providing a characteristic optical response when subjected to excitation light energy in the presence of said target analytes.

2. The sensor of claim 1 wherein said dye substrate is comprised of a fibrous material.

3. The sensor of claim 2 wherein said fibrous material is selected from the group consisting of papers, tissues, textiles, woven fabrics, felts, fibers, fiber bundles, composites, and laminates of the same.

4. The sensor of claim 1 wherein said dye substrate is comprised of a particulate material.

5. The sensor of claim 4 wherein said particulate is selected from the group consisting of glasses, silicas, aluminas, ceramics, polymers, plastics, metals composites, sintered powders, and fritted assemblages of the same.

6. The sensor of claim 1 wherein said dye compound comprises a fluorescent dye.

7. The sensor of claim 6 wherein said dye compound further comprises a polymer.

8. The sensor of claim 6 wherein said dye fluorescent dye is a solvatochromic dye.

9. The sensor of claim 8 wherein said solvatochromic dye is selected from the group consisting of Nile Red, Prodan, 6-propionyl-2-(N,N-dimethylamino) napthalene, Acrylodan, and 6-acryloyl(dimethylamino) napthalene.

10. A sensor array for detecting target analytes in a fluid, said sensor array comprising:

a plurality of fluid-permeable, textured dye substrates having a high surface area and high surface area to volume ratio, said substrates having high open porosity, said substrates having high permeability to fluids;

a plurality of dye compounds dispersed on a plurality of internal and external surfaces within said textured dye substrates, said dye compounds providing a characteristic optical response when subjected to excitation light energy in the presence of a target analyte;

said dye substrates and said dye compounds forming a plurality of sensor array elements; and

a substrate support.

11. The sensor array of claim 10 wherein said dye substrates are comprised of a fibrous material.

12. The sensor of claim 11 wherein said fibrous material is selected from the group consisting of papers, tissues, textiles, woven fabrics, felts, fibers, fiber bundles, composites, and laminates of the same.

13. The sensor of claim 10 wherein said dye substrates are comprised of a particulate material.

14. The sensor of claim 13 wherein said particulate is selected from the group consisting of glasses, silicas, aluminas, ceramics, polymers, plastics, metals composites, sintered powders, and fritted assemblages of the same.

15. The sensor of claim 10 wherein said dye compounds comprise a fluorescent dye.

16. The sensor of claim 15 wherein said dye compounds further comprise a polymer.

17. The sensor of claim 15 wherein said fluorescent dye is a solvatochromic dye. selected from the group consisting of Nile Red, Prodan, 6-propionyl-2-(N,N-dimethylamino)napthalene, Acrylodan, and 6-acryloyl(dimethylamino) napthalene.

18. A sensor array according to claim 10 further comprising an excitation light energy source in optical communication with said sensor array elements.

19. A sensor array according to claim 11 further comprising an emission light energy detection means in optical communication with said sensor array elements.

20. A method for detecting a target analyte in a fluid comprising the steps of:

a) contacting said sample with a sensor array comprising;

i) a fluid-permeable, textured dye substrate having a high surface area and high. surface area to volume ratio, said substrate having high open porosity, said substrate having high permeability to fluids; and

ii) a dye compound dispersed on a plurality of internal and external surfaces within said textured dye substrate, said dye compound providing a characteristic optical response when subjected to excitation light energy in the presence of a target analyte; and

b) detecting the presence or absence of said target analyte.

21. The method of claim 20 wherein said contacting further comprises drawing said fluid into a sample chamber and exposing said array to said fluid for no more than five seconds.

22. The method of claim 20 wherein said detecting further comprises:

illuminating said sensor with excitation light energy; and

measuring an optical response produced by said sensor due to the presence of said analyte with a detector means.

23. The method of claim 22 further comprising identifying said analyte by employing a pattern-matching algorithm;

and

comparing said optical response of said sensor with said characteristic optical response.

24. The method of claim 22 further comprising identifying said analyte by providing spatio-temporal response patterns of said optical response;

and recognizing said patterns through a method selected from the group consisting of a template matching, neural networks, delay line neural networks, or statistical analysis.

25. A method for detecting a target analyte in a fluid comprising the steps of:

setting primary sampling parameters for a sensor array;

contacting said fluid with said array;

detecting a first plurality of optical responses produced by interaction of said fluid with said array;

comparing said first plurality of responses to a first stored spatio-temporal response for said primary parameters for said analyte;

setting secondary sampling parameters for said array wherein at least one sampling parameter is changed;

detecting a second plurality of optical responses produced by interaction of said fluid with said array;

comparing said second plurality of responses to a second stored spatio-temporal response for said secondary parameters for said analyte; and

detecting the presence or absence of said analyte.

26. The method of claim 25 wherein said setting primary sampling parameters comprises:

adjusting an excitation light source to a non-zero minimum intensity;

setting a fluid sampling time to a non-zero minimum time;

adjusting said fluid flow to a non-zero minimum flow rate; and

setting a number of sampling time points to a non-zero minimum.

setting a number of sniff samples to a maximum

27. The method of claim 25 wherein said setting secondary sampling parameters comprises:

incrementing said number of sniff samples by at least one;

selecting said at least one parameter setting from the group consisting of amplifier gain, fluid sampling time, fluid flow rate, number of sampling time points, sample sniff rate, amplifier high pass filtering, excitation light source intensity, and exhale velocity; and

modifying said at least one parameter setting from an initial setting value.

28. A sensing system for detecting and identifying an analyte in a fluid comprising:

a cross-reactive sensor array comprising

a plurality of dye compounds,

a plurality of porous, permeable, high surface area, textured dye substrates,

said dye compounds and said dye substrates forming a plurality of sensor elements,

a substrate support;

an excitation light source array comprising a plurality of light sources optically coupled to said sensor elements;

a detector array comprising a plurality of detectors optically coupled to said sensor elements;

a sample chamber for housing said sensor elements, said light source array, said detector array;

a sampling means enclosed in said chamber for drawing said fluid into said chamber for contact with said sensor array for a controlled exposure time;

a controller means in electrical communication with said light sources, said detectors, and said sampling means, said controller means electrically coordinating and switching said sampling means with said light sources and said detectors for sampling said fluid, measuring optical responses of said array sensors to said fluid, and detecting said analyte; and

an analyte identification algorithm for comparing said measured sensor optical responses to characteristic optical responses of said sensors to target analytes and identifying said analyte in said fluid.

29. A smart sensing system for intelligent detecting and identifying an analyte in a fluid comprising:

a cross-reactive sensor array comprising a plurality of sensors;

a detector array comprising a plurality of detectors in communication with said sensors;

a sampling chamber for housing said sensor array and said detector array;

a sampling means enclosed in said chamber for drawing said fluid into said chamber for contact with said sensor array for a controlled exposure time;

a microcontroller in electrical communication with said sampling means and said detector array, said controller means electrically coordinating and switching said sampling means and said detector array for sampling said fluid, measuring responses of said sensors to said fluid, detecting said analyte, and reporting an analyte detection result;

an intelligent sampling algorithm for directing said microcontroller, said sampling algorithm selecting sensors and detectors, said sampling algorithm coordinating said electrical communication for said switching, said sampling, said measuring, said detecting and said reporting, said sampling algorithm setting first and second sampling parameters; and

an analyte identification algorithm in communication with said sampling algorithm and said microcontroller, said identification algorithm comparing said measured sensor optical responses to characteristic responses of said sensors to target analytes and identifying said analyte in said fluid.

30. The sensing system of claim 29 wherein said identification algorithm comprises a response report comparing a spatio-temporal pattern of said measured optical responses to a spatio-temporal pattern of said characteristic responses;

and

an identification report selected from the group consisting of a pattern match, a delay line neural network match, and a neuronal network match.