Ammonia nanosensors, and environmental control system

• US 8,152,991 B2
• Filed: 12/08/2006
• Issued: 04/10/2012
• Est. Priority Date: 10/27/2005
• Status: Expired due to Fees

• Current Assignee: Nanomix Incorporated (CJY Holdings Ltd.)
• Original Assignee: Nanomix Incorporated (CJY Holdings Ltd.)
• Inventors: Gabriel, Jean-Christophe P., Gandhi, Shirpal C., Johnson, Bradley N, Ouborg, Willem-Jan, Passmore, John Loren, Ramakrishnan, Kastooriranganathan, Skarupo, Sergei, Briman, Mikhail, Star, Alexander, Bryant, Craig, Valcke, Christian, Chang, Ying-Lan
• Primary Examiner(s): BELL, BRUCE F
• Application Number:
  US11/636,360
• Publication Number:
  US 20080093226A1
• Time in Patent Office: 1,950 Days
• Field of Search: 204/403.01, 204/403.06, 204/403.13, 204/403.15, 204/406, 204/412, 204/424, 204/431, 204/433, 422/68.1, 422/81, 422/82.01, 422/82.02, 422/82.03, 422/83, 422/88, 422/90, 422/98, 205/775, 205/778, 205/781, 205/782, 205/782.5, 205/783, 205/785.5, 205/786, 205/787, 205/792, 205/794.5
• 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 method for controlling the operation of a sensor in monitoring an analyte in a sample environment, comprising:

(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 to determine the presence or concentration of the analyte by analysis of the dynamically sampled signal.

2. The method of claim 1, wherein selectively exposing includes regulating sensor exposure by means of one or both of a fluidic lumen and a valve.

3. The method of claim 1, 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.

4. The method of claim 3, wherein dynamically sampling includes limiting the analysis of the response signal to response magnitudes below a cut-off maximum.

5. The method of claim 3, wherein selectively exposing includes regulating sensor exposure to provide for non-exposed recovery time periods.

6. The method of claim 5, wherein the non-exposed recovery time periods are of a selected fixed duration.

7. The method of claim 1,

(a) wherein the sample environment includes at least one species which has a property effective to reduce the recovery time 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 reduce the recovery time of the sensor.

8. The method of claim 7 further comprising disposing a sensor apparatus including the sensor within the sample environment to monitor the concentration of the analyte within the sample environment.

9. The method of claim 7 further comprising monitoring the concentration of the analyte within a sample environment over a period greater than 20 days.

10. The method of claim 1 wherein the sensor comprises one or more nanostructured elements.

11. The method of claim 10 wherein the sensor portion comprises the one or more nanostructured elements.

12. The method of claim 10 wherein the one or more nanostructured elements comprise one or more carbon nanotubes.

13. The method of claim 1 further comprising analyzing the dynamic response signal to characterize an analyte concentration.

14. The method of claim 13 wherein analyzing the dynamic response signal comprises using a rise profile of a response curve to characterize an analyte concentration.

15. The method of claim 1, wherein the sensor is a field effect transistor-based sensor, and wherein the sensor portion is a nanostructured element spanning two electrodes.

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

(a) biasing a sensor using a fractional duty cycle; and

(b) dynamically sampling a response signal output from the sensor to determine the presence or concentration of the analyte by analysis of the dynamically sampled signal, wherein the dynamic sampling depends on the concentration of the analyte such that a specific sampling mode is applied in response to the presence of a predetermined concentration of analyte.

17. The method of claim 16 wherein the fractional duty cycle is selected to enhance the sensor use life.

18. The method of claim 16 wherein the sensor is a nanotube-based sensor.

19. The method of claim 16 wherein the sensor is a nanotube-based electrochemical sensor.

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

(a) applying a multiplex fluid flow sequence to the sensor during reagent exposure to generate a dynamic response signal output, wherein applying a multiplex fluid flow sequence comprises biasing a sensor electrode using a fractional duty cycle;

(b) analyzing the dynamic response signal output from the sensor to determine the presence or concentration of the analyte.

21. The method of claim 20 wherein the sensor is an electrochemical sensor.

22. The method of claim 20 wherein the sensor electrode is exposed to reagent during operation of the sensor.