Sensor platform using a horizontally oriented nanotube element

• US 7,780,918 B2
• Filed: 05/12/2004
• Issued: 08/24/2010
• Est. Priority Date: 05/14/2003
• Status: Active Grant

• Current Assignee: Nantero Incorporated
• Original Assignee: Nantero Incorporated
• Inventors: Vogeli, Bernhard, Segal, Brent M., Brock, Darren, Bertin, Claude L., Rueckes, Thomas, Jaiprakash, Venkatachalam C.
• Primary Examiner(s): FITZGERALD, JOHN P
• Application Number:
  US10/844,913
• Publication Number:
  US 20050053525A1
• Time in Patent Office: 2,295 Days
• Field of Search: 422/98, 422/88, 257/414, 324/715
• US Class Current: 422/98
• 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, and include platforms having horizontally oriented sensor elements comprising nanotubes or other nanostructures, such as nanowires. Under certain embodiments, a sensor element has an affinity for an analyte. Under certain embodiments, such a sensor element comprises one or more pristine nanotubes, and, under certain embodiments, it comprises derivatized or functionalized nanotubes. Under certain embodiments, a sensor is made by providing a support structure; providing a collection of nanotubes on the structure; defining a pattern within the nanotube collection; removing part of the collection so that a patterned collection remains to form a sensor element; and providing circuitry to electrically sense the sensor'"'"'s electrical characterization. Under certain embodiments, the sensor element comprises pre-derivatized or pre-functionalized nanotubes. Under certain embodiments, sensor material is derivatized or functionalized after provision on the structure or after patterning. Under certain embodiments, a large-scale array includes multiple sensors.

Claims

1. A sensor platform, comprising a sensor element comprising a patterned nonwoven 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

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

the patterned nonwoven nanotube fabric has at least two sides that are substantially parallel to each other and the patterned nonwoven nanotube fabric comprises a plurality of unaligned nanotubes.

2. The sensor platform of claim 1 wherein the sensor element also comprises at least one nanowire.

3. The sensor platform of claim 1 wherein the patterned nonwoven nanotube fabric has at least one lithographically defined lateral dimension.

4. The sensor platform of claim 1 wherein the sensor element has an affinity for at least two analytes and wherein the patterned nonwoven nanotube fabric includes 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.

5. 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.

6. The sensor platform of claim 1 wherein the sensor element rests flat on the support structure.

7. 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.

8. The sensor platform of claim 1 further comprising a first conductive element contacting the sensor element at a first point and a second conductive element contacting 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.

9. The sensor platform of claim 8 wherein the control circuitry comprises current-mirror circuitry to allow the resistance between the first and second contact points to be measured.

10. The sensor platform of claim 9 wherein the control circuitry comprises a reference resistor to allow measurement of the resistance between the first and second contact points relative to the resistance of the reference resistor.

11. The sensor platform of claim 10 wherein the reference resistor comprises a second patterned nonwoven nanotube fabric, and third and fourth conductive elements that contact the sensor element at separate points so that an electric current can run through the second patterned nonwoven nanotube fabric between the third and fourth conductive elements.

12. The sensor platform of claim 1 further comprising a conductive element located apart from the sensor element so that the conductive element and the sensor element are in a capacitive relationship.

13. The sensor platform of claim 12 wherein the sensor element is on one side of an insulating layer, and the conductive element is on another side of the insulating layer.

14. The sensor platform of claim 12 wherein the control circuitry comprises current-mirror circuitry to allow a capacitance associated with the conductive element and the sensor element to be measured.

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

16. The sensor platform of claim 15 wherein the reference capacitor comprises both a second patterned nonwoven nanotube fabric and a second conductive element that is separate from the second patterned nonwoven nanotube fabric, so that the second patterned nonwoven nanotube fabric and the second conductive element are in a capacitive relationship.

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

18. The sensor platform of claim 17 wherein the sensor element comprises at least one pristine nanotube.

19. The sensor platform of claim 17 wherein the sensor element comprises at least one nanotube that is derivatized to have or to increase the affinity.

20. The sensor platform of claim 17 wherein the sensor element comprises at least one nanotube that is functionalized to have or to increase the affinity.

21. The sensor platform of claim 17 wherein the support structure includes a channel and wherein the sensor element is suspended to span the channel.

22. The sensor platform of claim 21 wherein the support structure includes a conductive electrode positioned 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.

23. The sensor platform of claim 22 further including an upper electrode positioned above the sensor element.

24. A method of making the sensor platform of claim 1, comprising:

providing a support structure comprising a substrate;

providing a nonwoven nanotube fabric on the substrate;

defining a pattern within the nonwoven nanotube fabric such that the pattern corresponds to a sensor element;

removing a portion of the nonwoven nanotube fabric so that a patterned portion of the nonwoven nanotube fabric remains on the substrate to form a sensor element comprising a patterned nonwoven nanotube fabric and having an electrical characterization;

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

25. The method of claim 24 wherein the sensor element comprises at least one nanowire.

26. The method of claim 24 wherein the sensor element has an affinity for at least two analytes and wherein the plurality of nanotubes includes 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.

27. The method of claim 24 further including defining a fluidic separator in fluid communication with the sensor element to deliver a fluid potentially having the analyte.

28. The method of claim 24 wherein the sensor element rests flat on the substrate.

29. The method of claim 24 wherein the sensor element is made of pre-derivatized nanotubes.

30. The method of claim 24 wherein the sensor element is made of pre-functionalized nanotubes.

31. The method of claim 24 further comprising derivatizing at least a portion of the nonwoven nanotube fabric.

32. The method of claim 24 further comprising functionalizing at least a portion of the nonwoven nanotube fabric.

33. The method of claim 24 further comprising derivatizing at least a portion of the patterned nonwoven nanotube fabric remaining on the substrate.

34. The method of claim 24 further comprising functionalizing at least a portion of the patterned nonwoven nanotube fabric remaining on the substrate.

35. The method of claim 24, further comprising

providing a layer of covering material on one side of the nonwoven nanotube fabric;

removing a portion of the covering material to expose a portion of the nonwoven nanotube fabric.

36. The method of claim 24, further comprising

providing a first layer of a first covering material on one side of the nonwoven nanotube fabric;

providing a second layer of a second covering material on one side of the nonwoven nanotube fabric;

removing a portion of the second covering material;

annealing portions of the first and second covering materials.

37. The method of claim 24 wherein the nonwoven nanotube fabric is formed by depositing a solution of suspended nanotubes on the substrate.

38. The method of claim 37 wherein the nanotubes are derivatized to have an affinity for a corresponding analyte.

39. The method of claim 37 wherein the nanotubes are functionalized to have an affinity for a corresponding analyte.

40. The method of claim 24 further comprising providing a first conductive element that contacts the sensor element at a first point and providing a second conductive element that 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.

41. The method of claim 40 wherein the control circuitry comprises current-mirror circuitry to allow the resistance between the first and second contact points to be measured.

42. The method of claim 40 further comprising providing a reference resistor to allow measurement, relative to the resistance of the reference resistor, of the resistance associated with current running through the sensor element between the first and second conductive elements.

43. The method of claim 42 wherein the reference resistor comprises both a second nonwoven nanotube fabric and a third conductive element and a fourth conductive element that contact the second nonwoven nanotube fabric at separate points, so that an electric current can run through the sensor element between the third and fourth conductive elements.

44. The method of claim 24 further comprising providing a conductive element located apart from the sensor element so that the sensor element and the conductive element have a capacitive relationship.

45. The method of claim 44 further comprising providing an insulating layer between the conductive element and the sensor element.

46. The method of claim 44 wherein the control circuitry comprises current-mirror circuitry to allow a capacitance associated with the conductive element and the sensor element to be measured.

47. The method of claim 44 further comprising providing a reference capacitor to allow measurement of the capacitance associated with the sensor element and conductive element relative to the capacitance of the reference capacitor.

48. The method of claim 47 wherein the reference capacitor comprises both a second nonwoven nanotube fabric and a second conductive element that is separate from the second nonwoven nanotube fabric, so that the second nonwoven nanotube fabric and the second conductive element have a capacitive relationship.

49. The method of claim 24 wherein the sensor element has an affinity for the corresponding analyte.

50. The method of claim 49 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.

51. The method of claim 49 wherein the resulting sensor element comprises at least one pristine nanotube.

52. The method of claim 49 wherein the resulting sensor element comprises at least one nanotube that is derivatized to have or to increase the affinity.

53. The method of claim 49 wherein the resulting sensor element comprises at least one nanotube that is functionalized to have or to increase the affinity.

54. The method of claim 49 wherein the support structure includes a channel and wherein the sensor element is suspended to span the channel.

55. The method of claim 54 wherein the support structure includes a conductive electrode positioned 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.

56. The method of claim 55 further including an upper electrode positioned above and separated from the sensor element.

57. 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 patterned nonwoven 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

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, wherein

the patterned nonwoven nanotube fabric has at least two sides that are substantially parallel to each other and the patterned nonwoven nanotube fabric comprises a plurality of unaligned nanotubes.

58. The large-scale array of claim 57 wherein the sensor element comprises at least one nanowire.

59. A sensor platform, comprising

a sensor element comprising a patterned nonwoven nanotube fabric and having an electrical characterization;

a support structure for supporting the sensor element;

a conductive element located apart from the sensor element to form a structure in which the conductive element and sensor element are in a capacitive relationship; and

control circuitry to electrically sense an electrical value reflecting a capacitance associated with the sensor element and the conductive element;

wherein

the patterned nonwoven nanotube fabric has at least two sides that are substantially parallel to each other and the patterned nonwoven nanotube fabric comprises a plurality of unaligned nanotubes.

60. The sensor platform of claim 59 wherein the sensor element comprises at least one nanowire.

61. The sensor platform of claim 59 wherein the sensor element is in one side of an insulating layer, and the conductive element is a conductive pad on another side of the insulating layer.

62. The sensor platform of claim 59 wherein the sensor element is substantially surrounded by support structure material so that it is not substantially exposed to potential contact with a fluid.

63. A method of making the sensor platform of claim 59, comprising

providing a support structure comprising a substrate;

providing a nonwoven nanotube fabric on the support structure;

defining a pattern within the nonwoven nanotube fabric such that the pattern corresponds to a sensor element;

removing a portion of the nonwoven nanotube fabric so that patterned portion of the nonwoven nanotube fabric remains on the substrate to form a sensor element comprising a patterned nonwoven nanotube fabric and having an electrical characterization;

providing a conductive element located apart from the sensor element to form a structure in which the conductive element and sensor element are in a capacitive relationship;

providing control circuitry to electrically sense a capacitance associated with the conductive element and the sensor element.

64. The method of claim 63 wherein the sensor element comprises at least one nanowire.

65. The method of claim 63 further comprising providing an insulating layer between the conductive element and the sensor element.

66. The method of claim 63 further comprising providing covering material in contact with the sensor element so that it is not substantially exposed to potential contact with a fluid.

67. A large-scale array of sensor platforms wherein the array includes a plurality of sensor platform cells, each of which comprises

a sensor element comprising a patterned nonwoven nanotube fabric and having an electrical characterization;

a support structure for supporting the sensor element;

a conductive element located apart from the sensor element to form a structure in which the conductive element and sensor element are in a capacitive relationship; and

control circuitry to electrically sense an electrical value reflecting the capacitance associated with the sensor element and the conductive element, wherein

the patterned nonwoven nanotube fabric has at least two sides that are substantially parallel to each other and the patterned nonwoven nanotube fabric comprises a plurality of unaligned nanotubes.

68. The large-scale array of claim 67 wherein the sensor element comprises at least one nanowire.

69. A sensor platform, comprising

a sensor element comprising a patterned nonwoven nanowire fabric and having an electrical characterization;

a support structure for supporting the sensor element so that it may be exposed to a fluid;

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

wherein

the patterned nonwoven nanowire fabric has at least two sides that are substantially parallel to each other and the patterned nonwoven nanowire fabric comprises a plurality of unaligned nanowires.

70. The sensor platform of claim 69 wherein the sensor element also comprises at least one nanotube.

71. The sensor platform of claim 69 wherein the patterned nonwoven nanowire fabric has at least one lithographically defined lateral dimension.

72. The sensor platform of claim 69 wherein the sensor element has an affinity for at least two analytes and wherein the patterned nonwoven nanowire fabric includes at least two types of nanowires, a first type having an affinity for a first analyte and a second type having an affinity for a second analyte.

73. The sensor platform of claim 69 including a fluidic separator in fluid communication with the sensor platform to deliver a fluid potentially having the analyte.

74. The sensor platform of claim 69 wherein the sensor element rests flat on the support structure.

75. The sensor platform of claim 69 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.

76. The sensor platform of claim 69 further comprising a conductive element located apart from the sensor element so that the conductive element and the sensor element are in a capacitive relationship.

77. The sensor platform of claim 76 wherein the sensor element is on one side of an insulating layer, and the conductive element is on another side of the insulating layer.

78. The sensor platform of claim 76 wherein the control circuitry comprises current-mirror circuitry to allow a capacitance associated with the conductive element and the sensor element to be measured.

79. The sensor platform of claim 78 wherein the control circuitry comprises a reference capacitor to allow measurement of the capacitance associated with the sensor element and the conductive element relative to the capacitance of the reference capacitor.

80. The sensor platform of claim 79 wherein the reference capacitor comprises both a second patterned nonwoven nanowire fabric and a second conductive element that is separate from the patterned nonwoven nanowire fabric, so that the second nonwoven nanowire fabric and the second conductive element are in a capacitive relationship.

81. The sensor platform of claim 69 further comprising a first conductive element contacting the sensor element at a first point and a second conductive element contacting 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.

82. The sensor platform of claim 81 wherein the control circuitry comprises current-mirror circuitry to allow the resistance between the first and second contact points to be measured.

83. The sensor platform of claim 82 wherein the control circuitry comprises a reference resistor to allow measurement of the resistance between the first and second contact points relative to the resistance of the reference resistor.

84. The sensor platform of claim 83 wherein the reference resistor comprises a second patterned nonwoven nanowire fabric, and third and fourth conductive elements that contact the sensor element at separate points so that an electric current can run through the second patterned nonwoven nanowire fabric between the third and fourth conductive elements.

85. The sensor platform of claim 69 wherein the sensor element has an affinity for the corresponding analyte.

86. The sensor platform of claim 85 wherein the sensor element comprises at least one pristine nanowire.

87. The sensor platform of claim 85 wherein the sensor element comprises at least one nanowire that is derivatized to have or to increase the affinity.

88. The sensor platform of claim 85 wherein the sensor element comprises at least one nanowire that is functionalized to have or to increase the affinity.

89. The sensor platform of claim 85 wherein the support structure includes a channel and wherein the sensor element is suspended to span the channel.

90. The sensor platform of claim 89 wherein the support structure includes a conductive electrode positioned 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 nanowires in the sensor element may be electrically detected.

91. The sensor platform of claim 90 further including an upper electrode positioned above the sensor element.

92. A method of making the sensor platform of claim 69, comprising:

providing a support structure comprising a substrate;

providing a nonwoven nanowire fabric on the substrate;

defining a pattern within the nonwoven nanowire fabric such that the pattern corresponds to a sensor element;

removing a portion of the nonwoven nanowire fabric so that patterned portion of the nonwoven nanowire fabric remains on the substrate to form a sensor element comprising a patterned nonwoven nanowire fabric and having an electrical characterization;

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

93. The method of claim 92 wherein the sensor element comprises at least one nanotube.

94. The method of claim 92 wherein the sensor element has an affinity for at least two analytes and wherein the plurality of nanowires includes at least two types of nanowires, a first type having an affinity for a first analyte and a second type having an affinity for a second analyte.

95. The method of claim 92 further including defining a fluidic separator in fluid communication with the sensor element to deliver a fluid potentially having the analyte.

96. The method of claim 92 wherein the sensor element rests flat on the substrate.

97. The method of claim 92 wherein the sensor element is made of pre-derivatized nanowires.

98. The method of claim 92 wherein the sensor element is made of pre-functionalized nanowires.

99. The method of claim 92 further comprising derivatizing at least a portion of the nonwoven nanowire fabric.

100. The method of claim 92 further comprising functionalizing at least a portion of the nonwoven nanowire fabric.

101. The method of claim 92 further comprising derivatizing the patterned nonwoven nanowire fabric remaining on the substrate.

102. The method of claim 92 further comprising functionalizing the patterned nonwoven nanowire fabric remaining on the substrate.

103. The method of claim 92, further comprising

providing a layer of covering material on one side of the nonwoven nanowire fabric;

removing a portion of the covering material to expose a portion of the nonwoven nanowire fabric.

104. The method of claim 92, further comprising

providing a first layer of a first covering material on one side of the sensor element;

providing a second layer of a second covering material on one side of the sensor element;

removing a portion of the second covering material;

annealing portions of the first and second covering materials.

105. The method of claim 92 wherein the nonwoven nanowire fabric is formed by depositing a solution of suspended nanowires on the substrate.

106. The method of claim 105 wherein the nanowires are derivatized to have an affinity for a corresponding analyte.

107. The method of claim 105 wherein the nanowires are functionalized to have an affinity for a corresponding analyte.

108. The method of claim 92 further comprising providing a conductive element located apart from the sensor element so that the sensor element and the conductive element have a capacitive relationship.

109. The method of claim 108 further comprising providing an insulating layer between the conductive element and the sensor element.

110. The method of claim 108 wherein the control circuitry comprises current-mirror circuitry to allow a capacitance associated with the conductive element and the sensor element to be measured.

111. The method of claim 108 further comprising providing a reference capacitor to allow measurement of the capacitance associated with the sensor element and conductive element relative to the capacitance of the reference capacitor.

112. The method of claim 111 wherein the reference capacitor comprises both a second nonwoven nanowire fabric and a second conductive element that is separate from the second nonwoven nanowire fabric, so that the second nonwoven nanowire fabric and the second conductive element have a capacitive relationship.

113. The method of claim 92 further comprising providing a first conductive element that contacts the sensor element at a first point and providing a second conductive element that 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.

114. The method of claim 113 wherein the control circuitry comprises current-mirror circuitry to allow the resistance between the first and second contact points to be measured.

115. The method of claim 113 further comprising providing a reference resistor to allow measurement relative to the resistance of the reference resistor of the resistance associated with current running through the sensor element between the first and second conductive elements.

116. The method of claim 115 wherein the reference resistor comprises both a second nonwoven nanowire fabric and third and fourth conductive elements that contact the second collection of nanowires at separate points, so that an electric current can run through the sensor element between the third and fourth conductive elements.

117. The method of claim 92 wherein the sensor element has an affinity for the corresponding analyte.

118. The method of claim 117 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.

119. The method of claim 117 wherein the nanowires are pristine nanowires.

120. The method of claim 117 wherein the nanowires are derivatized to have or to increase the affinity.

121. The method of claim 117 wherein the nanowires are functionalized to have or to increase the affinity.

122. The method of claim 117 wherein the support structure includes a channel and wherein the sensor element is suspended to span the channel.

123. The method of claim 122 wherein the support structure includes a conductive electrode positioned 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 nanowires in the sensor element may be electrically detected.

124. The method of claim 123 further including an upper electrode positioned above and separated from the sensor element.

125. 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 patterned nonwoven nanowire fabric and having an electrical characterization;

a support structure for supporting the sensor element so that it may be exposed to a fluid;

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;

wherein

the patterned nonwoven nanowire fabric has at least two sides that are substantially parallel to each other and the patterned nonwoven nanowire fabric comprises a plurality of unaligned nanowires.

126. The large-scale array of claim 125 wherein the sensor element comprises at least one nanotube.

127. A sensor platform, comprising

a sensor element comprising a patterned nonwoven nanowire fabric and having an electrical characterization;

a support structure for supporting the sensor element;

a conductive element located apart from the sensor element to form a structure in which the conductive element and sensor element are in a capacitive relationship;

control circuitry to electrically sense an electrical value reflecting the capacitance associated with the sensor element and the conductive element;

wherein

the patterned nonwoven nanowire fabric has at least two sides that are substantially parallel to each other and the patterned nonwoven nanowire fabric comprises a plurality of unaligned nanowires.

128. The sensor platform of claim 127 wherein the sensor element comprises at least one nanotube.

129. The sensor platform of claim 127 wherein the sensor element is in one side of an insulating layer, and the conductive element is a conductive pad on another side of the insulating layer.

130. The sensor platform of claim 127 wherein the sensor element is substantially surrounded by support structure material so that it is not substantially exposed to potential contact with a fluid.

131. A method of making the sensor platform of claim 127, comprising

providing a support structure comprising a substrate;

providing a nonwoven nanowire fabric on the support structure;

defining a pattern within the nonwoven nanowire fabric such that the pattern corresponds to a sensor element;

removing a portion of the nonwoven nanowire fabric so that patterned portion of the nonwoven nanowire fabric remains on the substrate to form a sensor element comprising a patterned nonwoven nanowire fabric and having an electrical characterization;

providing a conductive element located apart from the sensor element to form a structure in which the conductive element and sensor element are in a capacitive relationship;

providing control circuitry to electrically sense a capacitance associated with the conductive element and the sensor element.

132. The method of claim 131 wherein the sensor element comprises at least one nanotube.

133. The method of claim 131 further comprising providing an insulating layer between the conductive element and the sensor element.

134. The method of claim 131 further comprising providing covering material in contact with the sensor element so that it is not substantially exposed to potential contact with a fluid.

135. A large-scale array of sensor platforms wherein the array includes a plurality of sensor platform cells, each of which comprises

a sensor element comprising a patterned nonwoven nanowire fabric and having an electrical characterization;

a support structure for supporting the sensor element;

a conductive element located apart from the sensor element to form a structure in which the conductive element and sensor element are in a capacitive relationship;

control circuitry to electrically sense an electrical value reflecting the capacitance associated with the sensor element and the conductive element;

wherein

the patterned nonwoven nanowire fabric has at least two sides that are substantially parallel to each other and the patterned nonwoven nanowire fabric comprises a plurality of unaligned nanowires.

136. The large-scale array of claim 135 wherein the sensor element comprises at least one nanotube.