Sensor for chemical and biological materials

• US 6,730,212 B1
• Filed: 10/03/2000
• Issued: 05/04/2004
• Est. Priority Date: 10/03/2000
• Status: Expired due to Fees

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Stanford, Thomas B. Jr., Van Ast, Camille I., Yamagishi, Frederick G.
• Primary Examiner(s): Olsen, Kaj K.
• Application Number:
  US09/679,428
• Time in Patent Office: 1,309 Days
• Field of Search: 204/403.01, 204/403.04, 204/403--40, 204/403.14, 205/777.5, 427/58, 427/213.3, 427/213.34
• US Class Current: 205/777.5
• CPC Class Codes: G01N 27/126 comprising organic polymers

Abstract

A sensor and method for detecting biological and chemical agents comprising metal interdigitized electrodes coated with hybrid polymer-based conducting film and an instrument for applying electrical voltage to the electrodes and registering the change in voltage. The hybrid film also comprises indicator biomolecules encapsulated within the film or attached to it. When these indicator biomolecules come in a contact with a biological and chemical agent, morphological changes occur in the film and electrical current flowing through the electrodes is modulated. The change in current indicates the presence of a biological and chemical agent and is registered.

Claims

1. A sensor for detecting a biological and/or chemical material in air, said sensor comprising:

(a) a dielectric substrate;

(b) interdigitated electrodes attached to said substrate;

(c) a film layer applied on top of said interdigitated electrodes, wherein the film layer comprises a conductive polymer and a sol-gel derived material;

(d) indicator biomolecules within said film layer; and

(e) an instrument to measure an electric current flowing through said interdigitated electrodes;

wherein the conductive polymer and the indicator biomolecules are encapsulated within the sol-gel derived material and are thoroughly dispersed throughout the film layer;

wherein the film layer directly contacts the air and the interdigitated electrodes;

wherein the sol-gel derived material is a first sol-gel derived material, and wherein the film layer is prepared by the following steps;

(1) forming a C-gel by encapsulating the conductive polymer in a second sol-gel derived material; and

(2) forming the film layer by co-encapsulating the C-gel and the indicator biomolecules in the first sol-gel derived material; and

wherein the first sol-gel derived material is different than the second sol-gel derived material.

2. The sensor of claim 1, wherein said dielectric substrate comprises glass, ceramic, and/or plastic material.

3. The sensor as claimed in claim 2, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

4. The sensor of claim 1, wherein said interdigitated electrodes are attached to said substrate by an adhesion layer.

5. The sensor of claim 4, wherein said adhesion layer comprises a material selected from a group consisting of titanium and an alloy of titanium and tungsten.

6. The sensor of claim 1, wherein said interdigitated electrodes each have a generally rectangular shape in a cross-section.

7. The sensor of claim 1, wherein said interdigitated electrodes each have a width within a range of between about 5 micrometers and about 25 micrometers.

8. The sensor of claim 1, wherein said interdigitated electrodes comprise a pair of electrodes defining a gap, wherein the gap is within a range of between about 5 micrometers and about 25 micrometers.

9. The sensor of claim 1, wherein said indicator biomolecules are selected from the group consisting of enzymes, antibodies, and deoxyribonucleic acid.

10. The sensor of claim 9, wherein said enzymes are selected from the group consisting of acetylcholineesterase and glucose oxidase.

11. The sensor as claimed in claim 9, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

12. The sensor of claim 1, wherein said instrument to measure said electric current is comprised of a voltage source and an amperometer.

13. The sensor of claim 1, wherein said interdigitated electrodes are fabricated of material comprising gold.

14. The sensor of claim 1, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate.

15. The sensor as claimed in claim 14, wherein the conductive polymer has no extractable counterions.

16. A method for detecting a biological and/or chemical material in air using the sensor claimed in claim 14, the method comprising:

(a) exposing the sensor to the chemical and/or biological material;

(b) applying an electric voltage to the interdigitated electrodes of the sensor; and

(c) measuring a change in an electric current flowing through the interdigitated electrodes, wherein the change is caused by interaction of the biological and/or chemical material with the film layer of the sensor.

17. The sensor of claim 1, wherein said first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane;

and

wherein the second sol-gel derived material comprises a product of gelation of a material selected from the group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

18. The sensor of claim 1, wherein said interdigitated electrodes each have a width of about 15 micrometers.

19. The sensor of claim 1, wherein said interdigitated electrodes comprise a pair of electrodes defining a gap, wherein the gap is about 15 micrometers.

20. The sensor as claimed in claim 1, wherein the conductive polymer has no extractable counterions.

21. The sensor as claimed in claim 20, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate,polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

22. The sensor as claimed in claim 1, wherein step (2) occurs in a buffered solution.

23. The sensor of claim 1, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

24. A method for detecting a biological and/or chemical material in air using the sensor claimed in claim 23, the method comprising:

(a) exposing the sensor to the chemical and/or biological material;

(b) applying an electric voltage to the interdigitated electrodes of the sensor; and

(c) measuring a change in an electric current flowing through the interdigitated electrodes, wherein the change is caused by interaction of the biological and/or chemical material with the film layer of the sensor.

25. A method for detecting a biological and/or chemical material in air using the sensor claimed in claim 1, the method comprising:

(a) exposing the sensor to the chemical and/or biological material;

(b) applying an electric voltage to the interdigitated electrodes of the sensor; and

(c) measuring a change in an electric current flowing through the interdigitated electrodes, wherein the change is caused by interaction of the biological and/or chemical material with the film layer of the sensor.

26. The sensor as claimed in claim 1, wherein the indicator biomolecules have an intrinsic steric conformation.

27. A method for detecting a biological and/or chemical material in air comprising the steps of:

(a) disposing interdigitated electrodes on a dielectric substrate;

(b) applying a film layer on top of said interdigitated electrodes, wherein the film layer comprises a conductive polymer and a first sol-gel derived material;

(c) incorporating indicator biomolecules into said film layer;

wherein the conductive polymer and the indicator biomolecules are encapsulated within the first sol-gel derived material and are thoroughly dispersed throughout the film layer; and

wherein the film layer directly contacts the air and the interdigitated electrodes;

(d) applying an electric voltage to said interdigitated electrodes; and

(e) measuring a change in an electric current flowing through said interdigitated electrodes, said change being caused by interaction of said biological and/or chemical material with said film layer;

wherein the steps (b) and (c) comprise the following steps;

(1) forming a C-gel by encapsulating the conductive polymer in a second sol-gel derived material; and

(2) forming the film layer by co-encapsulating the C-gel and the indicator biomolecules in the first sol-gel derived material; and

wherein the first sol-gel derived material is different than the second sol-gel derived material.

28. The method of claim 27, wherein in said step of attaching of said interdigitated electrodes, said dielectric substrate comprises glass, ceramic, and/or plastic material.

29. The method of claim 27, wherein said interdigitated electrodes are attached to said substrate with use of an adhesion layer.

30. The method of claim 29, wherein said adhesion layer comprises a material selected from a group consisting of titanium and an alloy of titanium and tungsten.

31. The method of claim 27, wherein said interdigitated electrodes each have a generally rectangular shape in a cross-section.

32. The method of claim 27, wherein said interdigitated electrodes each have a width within a range of between about 5 micrometers and about 25 micrometers.

33. The method of claim 27, wherein said interdigitated electrodes comprise a pair of electrodes defining a gap, wherein the gap is within a range of between about 5 micrometers and about 25 micrometers.

34. The method of claim 27, wherein in said step of incorporating said indicator biomolecules into said film layer, said indicator biomolecules are selected from the group consisting of enzymes, antibodies, and deoxyribonucleic acid.

35. The method of claim 34, wherein said enzymes are selected from the group consisting of acetylcholineesterase and glucose oxidase.

36. The method of claim 27, wherein said step of applying an electric voltage to said interdigitated electrodes comprises applying to said interdigitated electrodes an amount of voltage between about 5 millivolts and about 300 millivolts.

37. The method of claim 27, wherein said interdigitated electrodes are fabricated of an electrically conductive material comprising gold.

38. The method of claim 27, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate.

39. The method of claim 27, wherein said first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane;

and

wherein the second sol-gel derived material comprises a product of gelation of a material selected from the group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

40. The method of claim 27, wherein said interdigitated electrodes each have a width of about 15 micrometers.

41. The method of claim 27, wherein said interdigitated electrodes comprise a pair of electrodes defining a gap, wherein the gap is about 15 micrometers.

42. The method of claim 27, wherein said step of applying an electric voltage to said interdigitated electrodes comprises applying to said interdigitated electrodes an amount of voltage between about 10 millivolts and about 50 millivolts.

43. A sensor for detecting a biological and/or chemical material in air, said sensor comprising:

(a) a dielectric substrate;

(b) interdigitated electrodes attached to said substrate;

(c) a film layer applied on top of said interdigitated electrodes, wherein the film layer comprises a conductive polymer and a sol-gel derived material;

(d) indicator biomolecules within said film layer; and

(e) an instrument to measure an electric current flowing through said interdigitated electrodes;

wherein the conductive polymer and the indicator biomolecules are encapsulated within the sol-gel derived material and are thoroughly dispersed throughout the film layer;

wherein the film layer directly contacts the air and the interdigitated electrodes;

wherein the sol-gel derived material is a first sol-gel derived material, and wherein the film layer is prepared by the following steps;

(1) forming an E-gel by encapsulating the indicator biomolecules in a second sol-gel derived material;

(2) forming a C-gel by encapsulating the conductive polymer in a third sol-gel derived material; and

(3) forming the film layer by co-encapsulating the E-gel and the C-gel in the first sol-gel derived material; and

wherein the second sol-gel derived material is different than the third sol-gel derived material.

44. The sensor as claimed in claim 43, wherein the conductive polymer has no extractable counterions.

45. The sensor as claimed in claim 44, wherein step (3) occurs in a buffered solution.

46. The sensor as claimed in claim 43, wherein before the film layer is formed, the C-gel is exracted to remove excess acid.

47. The sensor as claimed in claim 46, wherein step (3) occurs in a buffered solution.

48. The sensor of claim 46, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane;

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the third sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

49. A method for detecting a biological and/or chemical material in air using the sensor claimed in claim 46, the method comprising:

(a) exposing the sensor to the chemical and/or biological material;

(b) applying an electric voltage to the interdigitated electrodes of the sensor; and

(c) measuring a change in an electric current flowing through the interdigitated electrodes, wherein the change is caused by interaction of the biological and/or chemical material with the film layer of the sensor.

50. The method as claimed in claim 49, wherein the conductive polymer of the sensor has no extractable counterions.

51. The sensor as claimed in claim 46, wherein the conductive polymer has no extractable counterions.

52. The sensor as claimed in claim 48, wherein the conductive polymer has no extractable counterions.

53. The sensor as claimed in claim 43, wherein before the film layer is formed, the C-gel is exracted with water to remove excess acid.

54. The sensor of claim 53, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane;

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the third sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

55. The sensor as claimed in claim 43, wherein step (3) occurs in a buffered solution.

56. The sensor of claim 43, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane;

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the third sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

57. A method for detecting a biological and/or chemical material in air using the sensor claimed in claim 43, the method comprising:

(a) exposing the sensor to the chemical and/or biological material;

(b) applying an electric voltage to the interdigitated electrodes of the sensor; and

(c) measuring a change in an electric current flowing through the interdigitated electrodes, wherein the change is caused by interaction of the biological and/or chemical material with the film layer of the sensor.

58. A sensor for detecting a biological and/or chemical material in air, said sensor comprising:

(a) a dielectric substrate;

(b) interdigitated electrodes attached to said substrate;

(c) a film layer applied on top of said interdigitated electrodes, wherein the film layer comprises a conductive polymer and a first sol-gel derived material;

(d) indicator biomolecules within said film layer; and

(e) an instrument to measure an electric current flowing through said interdigitated electrodes;

wherein the film layer is prepared by the following steps;

(1) forming an E-gel by encapsulating the indicator biomolecules in a second sol-gel derived material;

(2) forming a C-gel by encapsulating the conductive polymer in a third sol-gel derived material; and

(3) forming the film layer by co-encapsulating the E-gel and the C-gel in the first sol-gel derived material; and

wherein the second sol-gel derived material is different, than the third sol-gel derived material.

59. The sensor as claimed in claim 58, wherein the conductive polymer has no extractable counterions.

60. The sensor as claimed in claim 59, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane;

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the third sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

61. The sensor as claimed in claim 58, wherein before the film layer is formed, the C-gel is exracted to remove excess acid.

62. The sensor as claimed in claim 58, wherein before the film layer is formed, the C-gel is exracted with water to remove excess acid.

63. The sensor as claimed in claim 58, wherein step (3) occurs in a buffered solution.

64. The sensor of claim 58, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane;

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the third sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

65. The sensor as claimed in claim 64, wherein said dielectric substrate comprises glass, ceramic, and/or plastic material;

and wherein said indicator biomolecules are selected from the group consisting of enzymes, antibodies, and deoxyribonucleic acid.

66. A method for detecting a biological and/or chemical material in air using the sensor claimed in claim 58, the method comprising:

(a) exposing the sensor to the chemical and/or biological material;

(b) applying an electric voltage to the interdigitated electrodes of the sensor; and

(c) measuring a change in an electric current flowing through the interdigitated electrodes, wherein the change is caused by interaction of the biological and/or chemical material with the film layer of the sensor.

67. A sensor for detecting a biological and/or chemical material in air, said sensor comprising:

(a) a dielectric substrate;

(b) interdigitated electrodes attached to said substrate;

(c) a film layer applied on top of said interdigitated electrodes, wherein the film layer comprises a conductive polymer and a first sol-gel derived material;

(d) indicator biomolecules within said film layer; and

(e) an instrument to measure an electric current flowing through said interdigitated electrodes;

wherein the film layer is prepared by the following steps;

(1) forming a C-gel by encapsulating the conductive polymer in a second sol-gel derived material; and

(2) forming the film layer by co-encapsulating the C-gel and the indicator biomolecules in the first sol-gel derived material; and

wherein the first sol-gel derived material is different than the second sol-gel derived material.

68. The sensor as claimed in claim 67, wherein the conductive polymer has no extractable counterions.

69. The sensor as claimed in claim 68, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene slulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

70. The sensor as claimed in claim 67, wherein step (2) occurs in a buffered solution.

71. The sensor of claim 67, wherein said conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly (anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

72. The sensor as claimed in claim 71, wherein said dielectric substrate comprises glass, ceramic, and/or plastic material;

and wherein said indicator biomolecules are selected from the group consisting of enzymes, antibodies, and deoxyribonucleic acid.

73. A method for detecting a biological and/or chemical material in air using the sensor claimed in claim 67, the method comprising:

(a) exposing the sensor to the chemical and/or biological material;

(b) applying an electric voltage to the interdigitated electrodes of the sensor; and

(c) measuring a change in an electric current flowing through the interdigitated electrodes, wherein the change is caused by interaction of the biological and/or chemical material with the film layer of the sensor.

74. A method for making a sensor for detecting a biological and/or chemical material in air, the method comprising:

(1) providing a dielectric substrate with interdigitated electrodes attached to the substrate; and

(2) applying a film layer on top of the interdigitated electrodes;

wherein the,film layer comprises a conductive polymer, indicator biomolecules, and a first sol-gel derived material;

wherein the conductive polymer and the indicator biomolecules are encapsulated within the first sol-gel derived material;

wherein the film layer in step (2) is formed by the following steps;

(a) forming an E-gel by encapsulating the indicator biomolecules in a second sol-gel derived material;

(b) forming a C-gel by encapsulating the conductive polymer in a third sol-gel derived material; and

(c) forming the film layer by co-encapsulating the E-gel and the C-gel in the first sol-gel derived material; and

wherein the second sol-gel derived material is different than the third sol-gel derived material.

75. The method for making a sensor as claimed in claim 74, wherein the conductive polymer has no extractable counterions.

76. The method for making a sensor as claimed in claim 74, wherein before the film layer is formed, the C-gel is exracted to remove excess acid.

77. The method for making a sensor as claimed in claim 74, wherein step (c) occurs in a buffered solution.

78. The method for making a sensor as claimed in claim 74, wherein the conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane;

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the third sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.

79. A method for making a sensor for detecting a biological and/or chemical material in air, the method comprising:

(1) providing a dielectric substrate with interdigitated electrodes attached to the substrate; and

(2) applying a film layer on top of the interdigitated electrodes;

wherein the film layer comprises a conductive polymer, indicator biomolecules, and a first sol-gel derived material;

wherein the conductive polymer and the indicator biomolecules are encapsulated within the first sol-gel derived material; and

wherein the film layer in step (2) is formed by the following steps;

(a) forming a C-gel by encapsulating the conductive polymer in a second sol-gel derived material; and

(b) forming the film layer by co-encapsulating the C-gel and the indicator biomolecules in the first sol-gel derived material; and

wherein the first sol-gel derived material is different than the second sol-gel derived material.

80. The method for making a sensor as claimed in claim 79, wherein the conductive polymer has no extractable counterions.

81. The method for making a sensor as claimed in claim 79, wherein before the film layer is formed, the C-gel is exracted with water to remove excess acid.

82. The method for making a sensor as claimed in claim 79, wherein step (b) occurs in a buffered solution.

83. The method for making a sensor as claimed in claim 79, wherein the conductive polymer is selected from a group consisting of polyaniline, polythiophene, polypyrrole, poly(anilinesulfonic acid), polyaniline formate, poly(ethylenedioxythiophene)-polystyrene sulfonate, polyaniline dodecylbenzene sulfonate, polyaniline camphor sulfonate, and polyaniline dinonylnapthyl sulfonate;

wherein the first sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane; and

wherein the second sol-gel derived material comprises a product of gelation of a material selected from a group consisting of tetramethoxysiloxane, glycidoxypropyltrimethoxysiloxane, methyltrimethoxysilane, and n,p-styrylethyltrimethoxysiloxane.