Free-standing nanowire sensor and method for detecting an analyte in a fluid

• US 20040106203A1
• Filed: 12/03/2002
• Published: 06/03/2004
• Est. Priority Date: 12/03/2002
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Peters, Kevin, Williams, R. Stanley, Stasiak, James, McClelland, Paul H., Hackleman, David E., Pease, Grant
• Granted Patent: US 7,163,659 B2
• Time in Patent Office: Days
• US Class Current: 436/49
• CPC Class Codes: G01N 27/3278 involving nanosized elements, e.g. nanogaps or nanoparticles nanopores G01N33/48721; magnetic beads G01N27/745
• CPC Class Codes: Y10T 436/114998 with treatment or replacement of aspirator element [e.g., cleaning, etc.]

Abstract

A sensor device and method for detecting the presence of an analyte in a fluid solution are disclosed. The sensor device system can comprise a substrate and an array of free-standing nanowires attached to the substrate. The array can include individual free-standing nanowires wherein each of the individual free-standing nanowires have a first end and a second end. The first end can, in some embodiments, be attached to the substrate and the second end unattached to the substrate. Such individual free-standing nanowires are configured for electrical communication with other individual free-standing nanowires through the first end. A signal measurement apparatus can be electrically coupled to the array of free-standing nanowires for receiving electrical information from the array of free-standing nanowires.

Claims

1. A sensor device, comprising:

a substrate;

an array of free-standing nanowires, said array comprising individual free-standing nanowires, each of said individual free-standing nanowires having a first end and a second end, said first end being attached to the substrate and said second end being unattached to the substrate, said individual free-standing nanowires configured for electrical communication with other individual free-standing nanowires; and

a signal measurement apparatus electrically coupled to the array of free-standing nanowires for receiving electrical information from the array of free-standing nanowires.

2. A device as in claim 1, further comprising a power source configured for introducing current to the array of free-standing nanowires.

3. A device as in claim 1, further comprising a conductive or semi-conductive layer coated on the substrate, wherein the array of free-standing nanowires is attached to the substrate by the conductive or semi-conductive layer.

4. A device as in claim 3, wherein the conductive or semi-conductive layer comprises a material selected from the group consisting of silicon, germanium, silver, gold, zinc oxide, gallium arsenide, tin oxide, cadmium sulfide, cadmium telluride, cadmium selenide, and combinations thereof.

5. A device as in claim 1, wherein the substrate is conductive or semi-conductive.

6. A device as in claim 5, wherein the substrate comprises a material selected from the group consisting of silicon, germanium, silver, gold, zinc oxide, gallium arsenide, tin oxide, cadmium sulfide, cadmium telluride, cadmium selenide, and combinations thereof.

7. A device as in claim 1, wherein the array of free-standing nanowires has been grown on the substrate.

8. A device as in claim 1, wherein the array of free-standing nanowires is functionalized with a composition that is interactive with a predetermined analyte.

9. A device as in claim 8, wherein the composition is chemically attached to the array of free-standing nanowires.

10. A device as in claim 8, wherein the composition is deposited on the array of free-standing nanowires.

11. A device as in claim 8, wherein the composition is a dielectric coating, thereby providing a capacitive effect to the individual nanowire upon analyte attraction to the nanowires through the dielectric coating.

12. A device as in claim 8, wherein the composition is reactive with a predetermined analyte.

13. A device as in claim 1, wherein the array of free-standing nanowires is present on the substrate at a density of from 10⁴ to 10¹³ nanowires/cm².

14. A device as in claim 1, wherein each individual nanowire of the array of free-standing nanowires is from 10 nm to 100 nm in thickness, and from 50 nm to 1,000,000 nm in length.

15. A device as in claim 1, wherein the array of free-standing nanowires is of a material selected from the group consisting of metallic material, semi-conducting material, piezoelectric material, and insulated material.

16. A device as in claim 1, further comprising a test fluid in contact with the array of free-standing nanowires.

17. A device as in claim 16, said device configured for detection when the test fluid is a liquid solution or dispersion.

18. A device as in claim 16, said device configured for detection when the test fluid is a gaseous atmosphere.

19. A device as in claim 1, wherein the electrical information is current.

20. A device as in claim 1, wherein the array of free-standing nanowires attached to the substrate is a capacitive plate, said device further comprising an opposing capacitive plate positioned in proximity to the first capacitive plate to form a capacitive system, wherein upon application of a current, said capacitive system is configured for electrical communication between the first capacitive plate and the second capacitive plate in the presence of a fluid environment.

21. A device as in claim 20, further comprising a second capacitive system that is substantially the same as the capacitive system, said second capacitive system also being electrically coupled to the chip or computer wherein differential measurements comparing the capacitive system to the second capacitive system are obtainable.

22. A device as in claim 20, wherein the counter capacitive plate is substantially the same configuration as the array of free-standing nanowires attached to the substrate.

23. A device as in claim 1, further comprising a second substrate and a second array of free-standing nanowires configured substantially the same as the substrate and the array of free-standing nanowires, respectively, said second array also being electrically coupled to the chip or computer wherein differential measurements comparing conductance of the array and the second array are obtainable.

24. A device as in claim 23, further comprising a substantially sealed chamber surrounding the second array and the second substrate, said chamber filled with a predetermined fluid atmosphere providing a control system.

25. A device as in claim 21, further comprising a substantially sealed chamber surrounding the second capacitive system, said chamber being filled with a predetermined fluid atmosphere.

26. A device as in claim 24, wherein the fluid atmosphere is a gas atmosphere.

27. A device as in claim 25, wherein the fluid atmosphere is a gas atmosphere.

28. A device as in claim 1, said device being surrounded by an outer shell that electrically and environmentally shields the array.

29. A method of detecting the presence of an analyte in a test fluid environment, comprising:

providing a first array of free-standing nanowires that is interactive with an analyte, said first array of free-standing nanowires having individual nanowires that are electrically interactive with one another, said first array of free-standing nanowires being electrically coupled to a chip or computer that is human- or machine-readable;

exposing the first array of free-standing nanowires to a test fluid environment suspected of containing the analyte;

measuring an electrical property provided by the first array of free-standing nanowires upon exposure to the test fluid environment.

30. A method as in claim 29, further comprising the steps of

providing a second array of free-standing nanowires, said second array of free-standing nanowires having individual nanowires that are electrically interactive with one another, said second array of free-standing nanowires being electrically coupled to the chip or computer;

exposing the second array of free-standing nanowires to a control fluid environment;

comparing the electrical property provided by the second array of free-standing nanowires upon exposure a control fluid environment to the electrical property provided by the first array of free-standing nanowires, thereby providing a differential measurement.

31. A method as in claim 30, wherein the second array of free-standing nanowires is also configured to be interactive with the analyte, and wherein the control fluid environment is known to be void of the analyte, or is known to have a fixed concentration of the analyte, thereby providing a basis for the comparing step.

32. A method as in claim 30, wherein the second array of free-standing nanowires is configured to be non-interactive with the analyte, and wherein the control fluid environment and fluid environment are substantially the same fluid composition, thereby providing a basis for the comparing step.

33. A method as in claim 30, wherein the first array of free-standing nanowires is functionalized with a composition interactive with the analyte.

34. A method as in claim 30, wherein the first array of free-standing nanowires is functionalized with an insulating composition.

35. A method as in claim 30, wherein the electrical property of the array of free-standing nanowires is conductance or impedance at a predetermined frequency.

36. A method as in claim 34, wherein the electrical property between the analyte and at least one individual free-standing nanowires is capacitance or impedance at a predetermined frequency.

37. A method of detecting the presence of an analyte in a fluid environment, comprising:

providing a detecting system comprising a first capacitive plate having a first array of free-standing nanowires that is interactive with an analyte, said first array of free-standing nanowires comprising individual nanowires that are electrically interactive with one another, and a second capacitive plate positioned in proximity to the first capacitive plate such electrical communication between the first capacitive plate and the second capacitive plate occurs in the presence of the test fluid environment,

placing the test fluid environment in continuous contact with the first capacitive plate and the second capacitive plate;

applying electrical current to at least one of the first capacitive plate and the second capacitive plate; and

measuring an electrical property passed capacitively between the first capacitive plate and the second capacitive plate.

38. A method as in claim 37, further comprising the steps of:

providing a control system comprising a third capacitive plate and a fourth capacitive plate that are substantially configured the same as the first capacitive plate and the second capacitive plate, respectively, and

placing a control fluid that is known to be void of the analyte in continuous contact with third capacitive plate and the fourth capacitive plate, thereby providing a comparison basis for the measuring step.

39. A method as in claim 37, further comprising the step of:

providing a control system having a third capacitive plate and a fourth capacitive plate that are substantially configured the same as the first capacitive plate and the second capacitive plate, respectively, except that the nanowires of the third and fourth capacitive plates are not interactive with the analyte, and

placing the test fluid in contact with the control system, thereby providing a comparison basis for the measuring step.