Sensor platform using a non-horizontally oriented nanotube element

• US 7,786,540 B2
• Filed: 07/11/2007
• Issued: 08/31/2010
• Est. Priority Date: 05/14/2003
• Status: Active Grant

• Current Assignee: Nantero Incorporated
• Original Assignee: Nantero Incorporated
• Inventors: Bertin, Claude L., Vogeli, Bernhard, Brock, Darren K., Segal, Brent M., Rueckes, Thomas, Jaiprakash, Venkatachalam C.
• Primary Examiner(s): PERT, EVAN T
• Application Number:
  US11/827,393
• Publication Number:
  US 20080164541A1
• Time in Patent Office: 1,147 Days
• Field of Search: 257/414, 977/920, 977/924
• US Class Current: 257/414
• 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 27/4146 involving nanosized elements, e.g. nanotubes, nanowires
• CPC Class Codes: G11C 13/025 using fullerenes, e.g. C60, or nanotubes, e.g. carbon or silicon nanotubes
• CPC Class Codes: Y10S 977/902 Specified use of nanostructure
• CPC Class Codes: Y10S 977/904 for medical, immunological, body treatment, or diagnosis
• CPC Class Codes: Y10S 977/92 Detection of biochemical
• CPC Class Codes: Y10S 977/921 Of toxic chemical
• CPC Class Codes: Y10S 977/922 Of explosive material
• CPC Class Codes: Y10S 977/924 using nanostructure as support of dna analysis
• CPC Class Codes: Y10T 29/43 Electric condenser making
• CPC Class Codes: Y10T 29/49082 Resistor making

Abstract

Sensor platforms and methods of making them are described. A platform having a non-horizontally oriented sensor element comprising one or more nanostructures such as nanotubes is described. Under certain embodiments, a sensor element has or is made to have an affinity for an analyte. Under certain embodiments, such a sensor element comprises one or more pristine nanotubes. Under certain embodiments, the sensor element comprises derivatized or functionalized nanotubes. Under certain embodiments, a sensor is made by providing a support structure; providing one or more nanotubes on the structure to provide material for a sensor element; and providing circuitry to electrically sense the sensor element'"'"'s electrical characterization. Under certain embodiments, the sensor element comprises pre-derivatized or pre-functionalized nanotubes. Under other embodiments, sensor material is derivatized or functionalized after provision on the structure or after patterning. Under certain embodiments, a large-scale array of sensor platforms includes a plurality of sensor elements.

Claims

1. A sensor platform, comprising

a sensor element comprising a non-woven nanotube fabric and having an electrical characterization;

a support structure, comprising a substrate, for supporting the sensor element so that it may be exposed to a fluid, and having a major surface of the substrate substantially non-parallel to the sensor element; and

control circuitry to electrically sense the electrical characterization of the sensor element so that the presence of a corresponding analyte may be detected.

2. The sensor platform of claim 1 wherein the sensor element has an affinity for the corresponding analyte.

3. The sensor platform of claim 2 wherein the sensor element comprises at least one pristine nanotube.

4. The sensor platform of claim 2 wherein the sensor element comprises at least one nanotube derivatized to have or to increase the affinity.

5. The sensor platform of claim 2 wherein the sensor element comprises at least one nanotube functionalized to have or to increase the affinity.

6. The sensor platform of claim 1 wherein the sensor element has an affinity for at least two analytes and wherein the sensor element comprises at least two types of nanotubes, a first type having an affinity for a first analyte and a second type having an affinity for a second analyte.

7. The sensor platform of claim 2 wherein the support structure includes a channel and wherein the sensor element is suspended to span the channel.

8. The sensor platform of claim 7 wherein the support structure includes a first conductive electrode positioned, at least in part, in the channel, and wherein the sensor element is deflectable in response to the control circuitry to contact the electrode so that a gating effect of the nanotubes in the sensor element may be electrically detected.

9. The sensor platform of claim 8 further including a second conductive electrode positioned on a side of the sensor element opposite the first conductive electrode.

10. The sensor platform of claim 1 including a fluidic separator in fluid communication with the sensor platform to deliver a fluid potentially having the analyte.

11. The sensor platform of claim 1 wherein the sensor element rests flat on a portion of the support structure.

12. The sensor platform of claim 1 wherein the sensor element is oriented substantially perpendicular to the major surface of the substrate.

13. The sensor platform of claim 1 wherein the sensor element is reusable in that, after exposure to the corresponding analyte, the sensor element can be substantially returned to its pre-exposure state by applying a voltage.

14. The sensor platform of claim 1 wherein a conductive element is located apart from the sensor element to form a structure in which the conductive element and sensor element are in a capacitive relationship.

15. The sensor platform of claim 14 wherein the sensor element is on one side of an insulating layer, and the conductive element is a conductive pad that is on another side of the insulating layer.

16. The sensor platform of claim 14 wherein the control circuitry comprises current-mirror circuitry to allow a capacitance associated with the sensor element and the conductive element to be measured.

17. The sensor platform of claim 14 wherein the control circuitry comprises a reference capacitor to allow measurement of a capacitance associated with the sensor element and the conductive element to be measured relative to a capacitance of the reference capacitor.

18. The sensor platform of claim 17 wherein the reference capacitor comprises a second sensor element including a non-woven nanotube fabric and a second conductive element in spaced relation to the second sensor element, so that the second sensor element and the second conductive element are in a capacitive relationship.

19. The sensor platform of claim 1 wherein a first conductive element contacts the sensor element at a first point and a second conductive element contacts the sensor element at a second point so that an electric current can run through the sensor element between the first and second conductive elements.

20. The sensor platform of claim 19 wherein the control circuitry comprises current-mirror circuitry to allow a resistance between the first and second contact points to be measured.

21. The sensor platform of claim 19 wherein the control circuitry comprises a reference resistor to allow measurement relative to the resistance of the reference resistor of the resistance between the first and second contact points.

22. The sensor platform of claim 21 wherein the reference resistor comprises a second collection of nanotubes, and third and fourth conductive elements that contact the sensor element at separate points so that an electric current can run through the second collection of nanotubes between the third and fourth conductive elements.

23. The sensor platform of claim 1, further comprising a reference sensor element comprising a non-woven nanotube fabric that is substantially surrounded by support structure material so that it is not substantially exposed to potential contact with a fluid.

24. A large-scale array of sensor platforms wherein the array includes a large plurality of sensor platform cells, each cell comprising:

a sensor element comprising a non-woven nanotube fabric and having an electrical characterization;

a support structure for supporting the sensor element so that it may be exposed to a fluid, and having a major surface of the substrate substantially non-parallel to the sensor element; and

control circuitry to electrically sense the electrical characterization of at least one sensor element so that the presence of a corresponding analyte may be detected.

25. The large-scale array of claim 24 wherein the sensor element is oriented substantially perpendicular to the major surface of the substrate.