Ammonia nanosensors, and environmental control system

• US 20080093226A1
• Filed: 12/08/2006
• Published: 04/24/2008
• Est. Priority Date: 10/27/2005
• Status: Active Grant

• Current Assignee: Nanomix Incorporated (CJY Holdings Ltd.)
• Original Assignee: Nanomix Incorporated (CJY Holdings Ltd.)
• Inventors: Gandhi, Shripal, Ramakrishnan, Kastooriranganathan, Briman, Mikhail, Ouborg, Willem-Jan, Johnson, Bradley, Skarupo, Sergei, Chang, Ying-Lan, Bryant, Craig, Valcke, Christian, Star, Alexander, Gabriel, Jean-Christophe, Passmore, John
• Granted Patent: US 8,152,991 B2
• Time in Patent Office: Days
• US Class Current: 205/775
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01N 27/127 comprising nanoparticles
• CPC Class Codes: G01N 27/129 Diode type sensors, e.g. gas sensitive Schottky diodes capacitor type sensors G01N27/227; field-effect transistor type sensors G01N27/414
• CPC Class Codes: G01N 27/4146 involving nanosized elements, e.g. nanotubes, nanowires
• CPC Class Codes: G01N 33/0054 Ammonia
• CPC Class Codes: G01N 33/0062 concerning the measuring method or the display, e.g. intermittent measurement or digital display
• CPC Class Codes: G01N 33/0068 using a computer specifically programmed
• CPC Class Codes: H01L 29/0669 Nanowires or nanotubes carbon nanotubes as material of solid-state device active part H10K85/211
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y10S 977/957 Of chemical property or presence

Abstract

Embodiments of nanoelectronic sensors are described, including sensors for detecting analytes such ammonia. An environmental control system employing nanoelectronic sensors is described. A personnel safety system configured as a disposable badge employing nanoelectronic sensors is described. A method of dynamic sampling and exposure of a sensor providing a number of operational advantages is described.

Claims

1. A nanostructure sensor for sensing an analyte of interest in a sample, comprising:

a substrate;

a nanostructured element disposed adjacent the substrate;

one or more conducting elements in electrical communication with the first nanostructure; and

at least one functionalization operatively associated with the nanostructured element, the at least one functionalization configured to provide sensitivity for the analyte of interest.

2. A sensor as in claim 1, wherein the nanostructured element includes a network of carbon nanotubes disposed adjacent the substrate.

3. A sensor as in claim 2, wherein the analyte of interest includes ammonia.

4. A sensor as in claim 2, wherein the at least one functionalization includes an organic recognition material.

5. A sensor as in claim 4, wherein the organic recognition material includes a polymer.

6. A sensor as in claim 5, wherein the polymer includes at least one of a conductive polymer and a semi-conductive polymer.

7. A sensor as in claim 4, wherein the organic recognition material includes PABS.

8. A sensor as in claim 4, wherein the organic recognition material includes a non-ionic surfactant.

9. A sensor as in claim 4, wherein the organic recognition material includes glycerol.

10. A sensor as in claim 4, wherein the network includes at least one SWNTs which is stably associated with the organic recognition material prior to formation of the network.

11. A sensor as in claim 2, wherein the at least one functionalization includes an inorganic recognition material.

12. A sensor as in claim 2, wherein the one or more conducting elements includes a spaced-apart pair of conducting elements defining a conduction path through at least a portion of the network.

13. A sensor as in claim 12, wherein the conduction path includes electrical interconnections between carbon nanotubes.

14. A sensor as in claim 13, wherein substantially none of the nanotubes are in contact with both of the spaced-apart pair of conducting elements.

15. A sensor as in claim 1, further comprising a gate electrode configured to electrically influence the nanostructured element.

21. A sensor system, comprising:

a sensor as in claim 2, configured to expose at least a portion of the network and associated functionalization to the sample, and further comprising a contact in communication with the at least one conducting element, the contact exposed on the sensor surface;

a sensor socket, including;

a body configured to engage and mount the sensor;

at least one pin configured to electrically communicate with at least the contact when the sensor is mounted in the socket, the pin configured to communicate at least one signal to measurement circuitry; and

an opening configured to provide that the portion of the network and associated functionalization communicates with the sample.

22. A sensor system as in claim 21, wherein the sensor is disposable.

23. A sensor system as in claim 21, wherein the analyte of interest includes ammonia.

24. An control system for regulating the internal environment of an enclosed volume, comprising:

a sensor as in claim 1;

a processor in communication with the sensor so as to receive at least one signal indicative of a concentration of the analyte of interest, the processor configured to send at least a command signal to an environmental actuator in response to the at least one signal, the command suited to cause the environmental actuator to control the concentration of the analyte of interest in the enclosed volume.

25. A sensor system as in claim 24, wherein the sensor is disposable.

26. A sensor system as in claim 24, wherein the analyte of interest includes ammonia.

27. An personnel safety badge for monitoring at least one analyte of interest in the environment of a user, comprising:

a badge body, configured to be worn by the user;

a sensor as in claim 2, disposed adjacent to the body and configured to measure the analyte of interest;

a processor disposed adjacent to the body and in communication with the sensor so as to receive at least one signal indicative of a concentration of the analyte of interest;

a power source disposed adjacent to the body and in communication with the processor; and

a least one warning output device disposed adjacent to the body, in communication with the processor, and produce at least one communication to the user in response to a concentration of the analyte of interest in the environment of a user.

16. A nanostructure sensor for sensing an analyte of interest, comprising:

a substrate, the substrate including a generally sheet-like base material and at least one conductor formed on a surface of the substrate;

a network of nanostructures deposited on the substrate so as to contact the at least one conductor formation, the network being deposited on the substrate subsequent to the forming of the at least one conductor;

a recognition material disposed in associated with the network of nanostructures, the recognition material configured to interact with the analyte of interest.

17. A sensor as in claim 16, wherein the substrate comprises a flexible polymeric material, and wherein the network of nanostructures includes carbon nanotubes deposited upon the substrate from a liquid suspension.

18. A sensor as in claim 17, wherein the substrate comprises a flexible polymeric material, and wherein the network of nanostructures includes carbon nanotubes deposited upon the substrate from a liquid suspension.

19. A sensor as in claim 18, wherein the recognition material is associated with the nanotubes prior to the deposition of the nanotubes from liquid suspension.

20. A sensor as in claim 18, wherein the sensor includes at least a pair of conductors formed on the substrate in a spaced-apart arrangement, the network of nanotubes configured to electrically communicate between the pair of conductors, and the recognition material configured so that the interaction of the recognition material with the analyte of interest produces a change in the conductivity of the network between the pair of conductors.

30. A method for controlling the operation of a sensor in monitoring an analyte in a sample environment, comprising the steps of:

(a) selectively exposing at least a portion of a sensor to the environment so that the sensor portion is exposed only intermittently; and

(b) dynamically sampling a response signal output from the sensor so as to determine the presence or concentration of the analyte of by analysis of the dynamically sampled signal.

28. A sensor system as in claim 30, wherein the sensor is disposable.

29. A sensor system as in claim 30, wherein the analyte of interest includes ammonia.

31. The method of claim 30, wherein selectively exposing includes regulating sensor exposure by means of one or both of a fluidic lumen and a valve.

32. The method of claim 30, wherein dynamically sampling includes analysis of the sensor signal limited to one or more of selected ranges of sensor response and selected time intervals of sensor exposure to the environment.

33. The method of claim 32, wherein dynamically sampling includes limiting the analysis of the response signal to response magnitudes below a cut-off maximum.

34. The method of claim 32, wherein selectively exposing includes regulating sensor exposure to provide for non-exposed recovery time periods of a selected fixed duration.

35. The method of claim 34, wherein the non-exposed recovery time periods are of a selected fixed duration.

36. The method of claim 30,

(a) wherein the sample environment includes at least one species which has a property effective to do at least one of:

reduce a useful-life of the sensor, increase a recovery time of the sensor, and reduce a time-between-servicing of the sensor, and

(b) wherein the intermittent exposure of the sensor to the environment defines periods of exposure and periods of non-exposure, which periods of non-exposure are effective to do at least one of;

increase the useful-life of the sensor, reduce the recovery time of the sensor, and increase the time-between-servicing of the sensor.

37. The method of claim 36, wherein the operation of the sensor during periods of non-exposure is effective to permit improved accuracy of the sensor during periods of exposure.