Biosensors including metallic nanocavities

• US 20100256016A1
• Filed: 08/02/2006
• Published: 10/07/2010
• Est. Priority Date: 08/02/2005
• Status: Active Grant

• Current Assignee: University of Utah (State of Utah)
• Original Assignee: University of Utah Research Foundation (State of Utah)
• Inventors: Liu, Yongdong, Mahdavi, Farhad, Nahata, Ajay, Blair, Steven M., Herron, James N.
• Granted Patent: US 9,012,207 B2
• Time in Patent Office: Days
• US Class Current: 506/13
• 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: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G01N 2021/6439 with indicators, stains, dyes, tags, labels, marks
• 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 21/648 using evanescent coupling or surface plasmon coupling for the excitation of fluorescence
• CPC Class Codes: G01N 21/7746 the waveguide coupled to a cavity resonator
• CPC Class Codes: G01N 33/54373 involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings
• CPC Class Codes: G02B 2207/101 Nanooptics
• CPC Class Codes: G02B 5/008 Surface plasmon devices diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553

Abstract

A biomolecular assay includes a substrate with a metallic layer on at least one surface thereof. The metallic film includes nanocavities. The nanocavities are configured to enhance signals that are representative of the presence or amount of one or more analytes in a sample or sample solution, and may be configured to enhance the signal by a factor of about two or more or by a factor of about three or more. Such signal enhancement may be achieved with nanocavities that are organized in an array, randomly positioned nanocavities, or nanocavities that are surrounded by increased surface area features, such as corrugation or patterning, or nanocavities that have quadrilateral or triangular shapes with tailored edge lengths, or with a plurality of nanoparticles. Methods for fabricating biomolecular substrates and assay techniques in which such biomolecular substrates are used are also disclosed.

Claims

1. A detection-enhancement element for a biological assay, comprising:

a substrate;

a metallic layer on at least one surface of the substrate and including at least one nanocavity formed in the metallic layer and extending to the substrate having sidewalls defined by the metallic layer and a bottom defined by the substrate, wherein an entire surface of the metallic layer is passivated to resist binding of capture molecules to the metallic layer; and

capture molecules within the at least one nanocavity and immobilized to the substrate at the bottom of the at least one nanocavity.

3. The detection-enhancement element of claim 1, wherein the metallic layer comprises gold.

4. The detection-enhancement element of claim 1, wherein the at least one nanocavity enhances a signal representative of an amount of at least one analyte present in a sample.

5. The detection-enhancement element of claim 4, wherein the metallic layer used with the substrate enhances a fluorescence signal that indicates binding of at least one of an analyte and a competing molecule with a capture molecule within the at least one nanocavity.

6. The detection-enhancement element of claim 1, wherein the at least one nanocavity has a width of about 100 nm to about 150 nm.

7. The detection-enhancement element of claim 6, wherein the width is a diameter.

8. The detection-enhancement element of claim 1, wherein the at least one nanocavity is spaced, on average, about 0.5 micrometers to about 0.6 micrometers apart from another nanocavity.

9. The detection-enhancement element of claim 1, comprising a plurality of nanocavities organized in an array.

11. The detection-enhancement element of claim 1, wherein the at least one nanocavity is surrounded by a predetermined corrugated pattern of increased surface area features.

24. The detection-enhancement element of claim 4, wherein the nanocavity enhances the signal by a factor at about 2 or more.

25. The detection-enhancement element of claim 24, wherein the nanocavity is square.

26. The detection-enhancement element of claim 25, wherein the nanocavity has an edge length of about 125 nm.

27. The detection-enhancement element of claim 24, wherein the nanocavity is triangular.

28. The detection-enhancement element of claim 4, wherein the nanocavity enhances the signal by a factor of about 3 or more.

29. The detection-enhancement element of claim 28, wherein the nanocavity is triangular.

30. The detection-enhancement element of claim 29, wherein the nanocavity has edges that are about 175 nm long.

31. The detection-enhancement element of claim 30, wherein the metallic layer comprises gold.

32. The detection-enhancement element of claim 31, wherein the metallic layer has a thickness of about 100 nm.

44. The detection-enhancement element of claim 31, wherein the metallic layer has a thickness of about 50 nm to about 100 nm.

45. The detection-enhancement element of claim 4, wherein the nanocavity is configured to enhances the signal by a factor at about 6 or more.

46. The detection-enhancement element of claim 4, wherein the nanocavity is configured to enhances the signal by a factor at about 12 or more.

47. The method of claim 1, wherein the passivated layer is selected from the group consisting of polyethylene glycol (PEG)-thiol.

53. The detection-enhancement element of claim 1, wherein the at least one nanocavity comprises a polygonal shape having a diameter, wherein the diameter comprises the largest distance between any pair of vertices of the polygonal shape.

2. (Canceled)

10. (Canceled)

12. (Canceled)

13. (Canceled)

48. The method of claim 13, wherein the passivated layer is selected from the group consisting of polyethylene glycol (PEG)-thiol.

14. (Canceled)

15. (Canceled)

21. (Canceled)

22. (Canceled)

23. A biomolecular assay technique, comprising:

introducing a sample or sample solution into nanocavities formed in a metallic film of a biomolecular assay;

introducing electromagnetic radiation of at least one wavelength into a substrate of the biomolecular assay, at least some of the electromagnetic radiation being internally reflected within the substrate;

detecting at least one enhanced signal representative of a presence or amount of at least one type of analyte present in the sample from the nanocavities.

33. A method for designing an apparatus for use in a biomolecular assay, comprising:

configuring a substrate;

configuring a metallic layer to

be included on at least one surface of the substrate; and

include a plurality of nanocavities that enhance a signal representative of an amount of analyte in a sample.

34. The method of claim 33, configuring the metallic layer further comprises:

configuring the metallic layer to have a thickness of about 100 nm.

35. The method of claim 33, wherein configuring the metallic layer to include a plurality of nanocavities comprises configuring at least one nanocavity of the plurality to enhance the signal by a factor of about 2 or more.

36. The method of claim 35, wherein configuring at least one nanocavity includes configuring the at least one nanocavity to have a shape that enhances the signal.

37. The method of claim 36, wherein configuring at least one nanocavity further includes configuring the at least one nanocavity to have dimensions that enhance the signal.

38. The method of claim 35, wherein configuring at least one nanocavity comprises configuring the at least one nanocavity to enhance the signal by a factor of about 3 or more.

39. The method of claim 38, wherein configuring at least one nanocavity includes configuring the at least one nanocavity to be triangular in shape.

40. The method of claim 39, wherein configuring at least one nanocavity further includes configuring sides of the at least one nanocavity to have lengths of about 175 nm each.

43. The method of claim 33, configuring the metallic layer further comprises:

configuring the metallic layer to have a thickness of about 50 nm to about 100 nm.

41. A method for fabricating a biomolecular assay, comprising:

forming a substrate;

depositing a metallic film onto at least one surface of the substrate;

forming a plurality of nanocavities within the metallic film, at least some of the nanocavities exposing corresponding areas on at least one surface of the substrate, at least one nanocavity of the plurality being configured to enhance a signal representative of binding of analyte by capture molecules by a factor of about 2 or more; and

introducing capture molecules at least into nanocavities of the plurality of nanocavities.

42. A biomolecular assay technique, comprising:

introducing a sample or sample solution into nanocavities formed in a metallic film of a biomolecular assay;

introducing electromagnetic radiation of at least one wavelength into a substrate of the biomolecular assay, at least some of the electromagnetic radiation being internally reflected within the substrate, the metallic film and a configuration of at least one aperture therein amplifying a signal representative of a presence of at least one type of analyte present in the sample by a factor of about two or more to generate at least one enhanced signal;

detecting the at least one enhanced signal.

49. (Canceled)

50. A detection-enhancement element for a biological assay, comprising:

a substrate;

a metallic layer on at least one surface of the substrate and including at least one nanocavity formed in the metallic layer having sidewalls defined by the metallic layer;

wherein the at least one nanocavity creates an exposed surface of the substrate and the exposed surface of the substrate is passivated to resist binding of capture molecules to the exposed surface of the substrate; and

capture molecules within the at least one nanocavity immobilized to a sidewall of the metallic layer within the at least one nanocavity.

16. The apparatus of claim 50, wherein the at least one nanocavity enhances a signal representative of an amount of at least one analyte present in a sample.

17. The apparatus of claim 50, wherein the metallic layer enhances a fluorescence signal that indicates binding of at least one of an analyte and a competing molecule with a capture molecule within the at least one nanocavity of the metallic substrate.

18. The apparatus of claim 50, wherein the substrate comprises quartz.

19. The apparatus of claim 50, wherein the metallic layer comprises gold.

20. The apparatus of claim 50, wherein the at least one nanocavity is surrounded by a predetermined corrugated pattern of increased surface area features.

51. A detection-enhancement element for a biological assay, comprising:

a substrate;

a metallic layer on at least one surface of the substrate and including at least one nanocavity formed in the metallic layer and extending to the substrate having sidewalls defined by the metallic layer and a bottom defined by the substrate;

a coating film covering a substantial portion of the metallic layer, wherein an exposed surface of the coating film and an exposed portion of the at least one surface of the substrate is passivated to resist binding of capture molecules to the coating film and the substrate; and

capture molecules within the at least one nanocavity and immobilized to a sidewall of the metallic layer within the at least one nanocavity.

52. A detection-enhancement element for a biological assay, comprising:

a substrate;

a metallic layer on at least one surface of the substrate and including at least one nanocavity surrounded by a predetermined corrugated pattern of increased surface area features; and

capture molecules within the at least one nanocavity.