CA2274245C - Sensors for electrically sensing binding events for supported molecular receptors - Google Patents
Sensors for electrically sensing binding events for supported molecular receptors Download PDFInfo
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- CA2274245C CA2274245C CA002274245A CA2274245A CA2274245C CA 2274245 C CA2274245 C CA 2274245C CA 002274245 A CA002274245 A CA 002274245A CA 2274245 A CA2274245 A CA 2274245A CA 2274245 C CA2274245 C CA 2274245C
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
- G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
- G01N33/558—Immunoassay; Biospecific binding assay; Materials therefor using diffusion or migration of antigen or antibody
- G01N33/559—Immunoassay; Biospecific binding assay; Materials therefor using diffusion or migration of antigen or antibody through a gel, e.g. Ouchterlony technique
Abstract
A first sensor (18) for electrically sensing a molecular binding event includes a receptor-supporting element (20) into which a reagent is diffusable, at feast one molecular receptor (22) supported by the recepto r- supporting element (20), and a first electrode (24) embedded in the receptor-supporting element (20). A second sensor for electrically sensing a molecular binding event includes a receptor-supporting element (130), at least one molecular receptor (132) supported by the recept or- supporting element (130), an electrode (134) coupled to the receptor-supporting element (130), and a porous electrode (136) coupled to t he receptor-supporting element (130).
Description
2 , PCT/US98/21251 -SENSORS FOR ELECTRICALLY SENSING BINDING EVENTS FOR
SUPPORTED MOLECULAR RECEPTORS
Technical Field The present invention relates to sensors for electrically sensing binding events with supported molecular receptors.
Background of the Invention U.S. Patent No. 5,552,270 to Khrapko et al.
describes a device for sequencing DNA by hybridization.
The device comprises an oligonucleotide array rigidly bound to a solid substrate. The oligonucleotide array consists of a multiplicity of gel portions separated from one another. Each gel portion contains one oligonucleotide of desired length.
Test DNA fragments are labeled with either a radioactive marker or a fluorescent marker. A solution including a buffer and the labeled test DNA fragments is applied to the device. The solution fully covers the gel portions containing immobilized oligonucleotides.
The labeled test DNA fragements hybridize with one or more of the oligonucleotides. After performing a washing step, hybridization events are detected by detecting the radioactive marker or-the fluorescent marker. A sequence associated with the test DNA
fragments is reconstructed by analyzing detection data.
lA
Two slides, one of which pretreated with Bind Silane and the other with Repel Silane (LKB) and lubricated with a thin layer of Triton X-100 are positioned at a distance from one another by means of 30 um thick spacers. The resulting clearance between the slides is filled with 8~
acrylamide solution, 30:1 N,N'-methylene bis-acrylamide, ammonium persulfate and TEMED, which is allowed to polymerize for 1 hour. As a result, a 30 um thick gel layer is formed between the slides, the dimensions of the layer being determined by the size of the slides. When the polymerization is complete, the upper slide is removed. The lower slide coated with a polyacrylamide layer is treated with 50~ hydrazine for 1 hour at room temperature. The bond between an oligonucleotide and polyacrylamide is stable enough to withstand at least 5 to 7 hybridization/washing cycles without any noticeable change in,its hybridizing properties. The half-life of the oligonucleotide-gel bond at 60° C. is 2 hours, and at 25° C., 36 hours.
It is desirable to detect the hybridization events without requiring that the test DNA fragments be labeled with radioactive markers or fluorescent markers.
Summary of the Invention The present invention seeks to overcome the disadvantages of the prior art associated with sensors for electrically sensing binding events for supported molecular receptors.
According to one aspect of the invention, a sensor is provided. The sensor comprises a receptor-supporting element into which a reagent is diffusable; at least one molecular receptor supported within the receptor-supporting element; and a first electrode embedded in the receptor-supporting element.
According to another aspect of the invention a sensor comprising: a first receptor-supporting element; a first at least one molecular receptor supported within the first receptor-supporting element; a first electrode coupled to the first receptor-supporting element; and a porous electrode coupled to the first receptor-supporting element.
According to another aspect of the invention a sensor comprising: a receptor-supporting element into which a reagent is diffusable; an annular-shaped electrode coupled to the receptor-supporting element; and an elongate electrode embedded in the receptor-supporting element.
According to a final aspect of the invention a sensor comprising: an annular-shaped, receptor-supporting element into which a reagent is diffusable; at least one molecular receptor supported within the annular-shaped, receptor-supporting element; and a first electrode and a second electrode coupled to the annular-shaped, receptor-supporting element.
The "Summary of the Invention " does not necessarily disclose all the inventive features. The inventions may reside in a sub-combination of the disclosed features.
Brief Description of the Drawings The invention is pointed out with particularity in the appended claims. However, other features of the invention will become more apparent and the invention will be best understood by referring to the following detailed description in conjunction with the accompanying drawings in which:
FIG. 1 is a block diagram of a sensor in accordance with the present invention;
FIG. 2 is a top view of a first embodiment of a sensor in accordance with the present invention;
FIG. 3 is a side sectional view of the embodiment of the sensor of FIG. 2;
FIG. 4 is a top view of a second embodiment of a sensor in accordance with the present invention;
FIG. 5 is a side sectional view of the embodiment of the sensor of FIG. 4;
FIG. 6 is a top view of a third embodiment of a sensor in accordance with the present invention;
FIG. 7 is a side sectional view of the embodiment of the sensor of FIG. 6;
FIG. 8 is a block diagram of another sensor in accordance with the present invention;
FIG. 9 is a side sectional view of an embodiment of the sensor of FIG. 8;
FIG. >.0 illustrates an embodiment of a one-dimensional array of sensors;
FIGS. 11 and 12 illustrate an embodiment of a two-dimensional array of sensors;
FTG. 13 is a top view of yet another embodiment of a sensor in accordance with the present invention; and FIG. 14 is a side sectional view of the embodiment of the sensor of FIG. 13.
wo ~nga42 rcrn~s9anms~ -Detailed Description of a Preferred Embodiment FIG. 1 is a block diagram of a sensor 18 in ' accordance with the present invention. The sensor 18 comprises a gel 20 which supports at least one molecular receptor 22. Preferably, the gel 20 supporting the at least one molecular receptor 22 is formed in accordance with U.S. Patent No. 5,552,270 to Khrapko et al.
;:
The at least one molecular receptor 22 is receptive to molecules having a predetermined and/or a preselected molecular structure. The at least one molecular receptor 22 can include either a biological molecule or a synthetic molecule having a specific affinity to its corresponding molecule. For example, each molecular receptor can include a chain of nucleotide bases to hybridize with a molecule having a complementary chain of nucleotide bases. In this case, each molecular receptor can include a DNA probe or a PNA probe for detecting a corresponding, complementary DNA base sequence, an RNA probe for detecting a corresponding, complementary RNA base sequence, or other DNA/RNA
analogues.
The sensor 18 includes a first electrode 24 embedded in the geI 20. The first electrode 24 is used to electrically sense hybridization or binding of at least one molecule 26 to the at least one molecular receptor 22. For example, the at least one molecule 26 can include a molecule having a plurality of nucleotide bases such as a DNA fragment or an RNA fragment to hybridize with the at least one molecular receptor 22.
Preferably, the first electrode 24 includes an elongate portion embedded in the gel 20. More preferably, the elongate portion is linear. ' Optionally, the sensor 1$ further includes a second electrode 30 coupled to the gel 20. The second electrode 30 can be either directly coupled, capacitively coupled, or inductively coupled to the gel 20. The second electrode 30 assists in electrically sensing the hybridization or binding of the at least one molecule 26 to the at least one molecular receptor 22.
Preferably, the second electrode 30 is disposed at a side of the gel 20. Additionally, the second electrode 30 can surround at least a portion of the gel and/or can surround at least a portion of the first electrode 24.
The second electrode 30 can include a cylindrical portion to surround or encircle the gel 20 and the first IS electrode 24. In this case, it is preferred that the first electrode 24 and the second electrode be generally coaxial. By "generally coaxial" it is meant that a first axis associated with the first electrode 24 is closer to being parallel to, rather than being 20 perpendicular to, a second axis associated with the second electrode 30.
A meter 32 is electrically connected to the first electrode 24 and the second electrode 30. The meter 32 is used to electrically detect a binding event between the at least one molecule 26 and the at least one molecular receptor 22. Preferably, the meter 32 includes an impedance meter, such as a capacitance meter or an inductance meter, to measure and/or detect a change in impedance between the first electrode 24 and the second electrode 30 resulting from the binding event. Alternatively, the meter 32 can measure and/or detect a charge associated with the binding event, or can measure and/or detect a resonance shift resulting from the binding event.
Generally, the meter 32 can detect a change in an electrical quantity (measured between the first electrode 24 and the second electrode 30) between two instances of time (e. g. a pre-binding time and a post-s binding time). Alternatively, the meter 32 can detect a change in an electrical quantity between the sensor 18 and a control sensor 34. The control sensor 34 can include a like gel having molecular receptors, a like first electrode, and a like second electrode as the sensor 18. The control sensor 34, however, is not exposed to the at least one molecule 26. The control sensor 34 is used as a calibration pixel for baseline subtraction.
FIG. 2 is a top view of a first embodiment of a sensor in accordance with the present invention. The sensor includes a gel member 40. The gel member 40 supports a plurality of molecular receptors (not specifically illustrated) such as those described with reference to FIG. 1. Although illustrated to have a rectangular cross section, the gel member 40 can have an alternatively-shaped cross section. Examples of alternatively-shaped cross sections include, but are not limited to, a polygonal cross section, an elliptical cross section, and a circular cross section.
The sensor includes a first electrode 42 and a second electrode 44. The first electrode 42 is embedded within the gel member 40. The second electrode 44 is coupled to a surface of the gel member 40.
Preferably, the first electrode 42 is directly coupled to the gel member 40. In this case, the first electrode 42 can directly contact an inner surface of the gel member 40. Alternatively, the first electrode 42 can be capacitively coupled to the gel member 40. In WO 99/18242 PCTlUS98/21251 this case, a dielectric material can be interposed between the first electrode 42 and a surface of the gel member 40.
Similarly, it is preferred that the second electrode 44 be directly coupled to the gel member 40.
In this case, the second electrode 44 can directly contact a surface of the gel member 40. Alternatively, the second electrode 44 can be capacitively coupled to the gel member 40. In this case, a sheet of dielectric material can be interposed between the second electrode 44 and a surface of the gel member 40.
The second electrode 44 defines an inner periphery 46 and an outer periphery 48. The inner periphery 46 defines an opening 50 that is completely covered by the gel member 40. The surface of the gel member 40 coupled to the second electrode 44 is bounded within the outer periphery 48.
Preferably, the inner periphery 46 and the outer periphery 48 are circular-shaped so that the second electrode 44 has the shape of a circular ring. It is noted, however, that the inner periphery 46 and the outer periphery 48 can be alternatively shaped to provide an alternative annular shape for the second electrode 44.
FIG. 3 is a side sectional view of the embodiment of the sensor of FIG. 2. As illustrated, the gel member 40, the first electrode 42, and the second electrode 44 are supported by a substrate 52. The substrate 52 has a surface 54 that supports the gel member 40. The second electrode 44 is integrated with the substrate 52 at the surface 54.
The first electrode 42 includes an elongate portion 56 embedded in the gel member 40. The elongate portion 56 has a length 58 greater than its width 60. Although the elongate portion 56 can be nonlinear, it is ' preferred that the elongate portion 56 be linear. The elongate portion 56 is oriented along an axis 62 transverse to the surface 54 of the substrate 52 and a surface 64 of the second electrode 44. The axis 62 extends through the opening SO of the second electrode 44.
It is preferred that the elongate portion 56 be generally normal to each of the aforementioned surfaces 54 and 64. By "generally normal" it is meant that an angle between the elongate portion 56 and a surface is greater than 45°. More preferably, the angle between the elongate portion 56 and each of the surfaces 54 and 64 is greater than 85°.
Preferably, the first electrode 42 extends through an entire dimension of the gel member 40 to provide an improved sensitivity for detecting binding events.
Generally, the first electrode 42 can extend substantially through an entire dimension of the gel member 40, i.e. through at least 50~ of a dimension of the gel member 40.
The first electrode 42 can be embedded in the gel member 40 using a variety of approaches. Using a first approach, the first electrode 42 includes a wire around which the gel member 40 is deposited. Using a second approach, the first electrode 42 includes a post fabricated by etching the substrate 52. The post is metallized before the gel member 40 is deposited.
Using a third approach, the substrate 52 is formed of a deformable material such as an elastic polymer or a plastic. A surface of the substrate 52 is metallized.
An elongate member such as a pin is applied to an opposing surface of the substrate 52. The pin deforms the substrate 52 to form the first electrode 42. In this case, the first electrode 42 may have a cone-like shape. The gel member 40 can be deposited either prior to or subsequent to the deformation of the substrate 52.
The first electrode 42 can be electrically connected through the substrate 52 to a first contact 64. Optionally, the second electrode 44 can be electrically connected through the substrate 52 to a second contact.
FIG. 4 is a top view of a second embodiment of a sensor in accordance with the present invention. The sensor includes a gel member 70. The gel member 70 supports a plurality of molecular receptors (not specifically illustrated) such as those described with reference to FIG. 1. Although illustrated to have a circular cross section, the gel member 70 can have an alternatively-shaped cross section. Examples of alternatively-shaped cross sections include, but are not limited to, a polygonal cross section.such as a rectangular cross section, and an elliptical cross section.
The sensor includes a first electrode 72 and a second electrode 74. The first electrode 72 is embedded within the gel member 70. The second electrode 74 is coupled to a surface of the gel member 70.
Preferably, the first electrode 72 is directly coupled to the gel member 70. In this case, the first electrode 72 can directly contact an inner surface of the gel member 70. Alternatively, the first electrode 72 can be capacitively coupled to the gel member 70. In this case, a dielectric material can be interposed between the first electrode 72 and a surface of the gel member 70.
Similarly, it is preferred that the second electrode 74 be directly coupled to the gel member 70. , In this case, the second electrode 74 can directly WO 99/18242 PCT/US98/2~251 -contact a side surface of the gel member 70.
Alternatively, the second electrode 74 can be capacitively coupled to the gel member 70. In this case, a sheet of dielectric material can be interposed between the second electrode 74 and the side surface of the gel member 70.
The second electrode 74 is cylindrically shaped to surround the gel member 70 and the first electrode 72.
Further, the second electrode 74 is coaxial with the first electrode 72.
FIG. 5 is a side sectional view of the embodiment of the sensor of FIG. 4. As illustrated, the gel member 70, the first electrode 72, and the second electrode 74 are supported by a substrate 82. The substrate 82 has a surface 84 that supports the gel member 70.
The first electrode 72 includes an elongate portion 86 embedded in the gel member 70. The elongate portion 86 has a length 88 greater than its width 90. Although the elongate portion 86 can be nonlinear, it is preferred that the elongate portion 86 be linear. The elongate portion 86 is oriented along an axis 92 transverse to the surface 84 of the substrate 82. The axis 92 also serves as an axis along which the second electrode 74 is~oriented.
It is preferred that the elongate portion 86 be generally normal to the surface 84. By "generally normal" it is meant that an angle between the elongate portion 86 and the surface 84 is greater than 45°. More preferably, the angle between the elongate portion 86 and the surface 84 is greater than 85°.
Preferably, the first electrode 72 and the second electrode 74 extend through an entire dimension of the gel member 70 to provide an improved sensitivity for detecting binding events. Generally, the first electrode 72 and the second electrode 74 can extend substantially through an entire dimension of the gel member 70, i.e. through at least 50~ of a dimension of the gel member 70.
It is noted that the first electrode 72 can be 5 formed and embedded in the gel member 70 using the approaches described with reference to FIG. 3.
The first electrode 72 can be electrically connected through the substrate 82 to a first contact 94. Optionally, the second electrode 74 can be 10 electrically connected through the substrate 82 to a second contact.
FIG. 6 is a top view of a third embodiment of a sensor in accordance with the present invention. The sensor includes a gel member 100. The gel member 100 supports a plurality of molecular receptors (not specifically illustrated) such as those described with reference to FIG. 1. Although illustrated to have a rectangular cross section, the gel member 100 can have an alternatively-shaped cross section. Examples of alternatively-shaped cross sections include, but are not limited to, a polygonal cross section, an elliptical cross section, and a circular cross section.
The sensor includes a first electrode 102 and a second electrode 104. The first electrode 102 is coupled to a first surface of the gel member 100. The second electrode 104 is coupled to a second surface of the gel member 100. Preferably, the first surface and the second surface are opposing surfaces of the gel member 100.
Preferably, the first electrode 102 and the second electrode 104 are directly coupled to the gel member 100. In this case, the first electrode 102 can directly contact the first surface and the second electrode 104 can contact the second surface. Alternatively, the first electrode 102 and the second electrode can be capacitively coupled to the geI member I00. In this case, a sheet of dielectric material can be interposed between the first electrode 102 and the first surface, and between the second electrode 109 and the second 5 surface.
FIG. 7 is a side sectional view of the embodiment of the sensor of FIG. 6. As illustrated, the gel member 100, the first electrode 102, and the second electrode 104 are supported by a substrate 112. The substrate 112 has a surface 119 that supports the gel member 100.
The first electrode 102 includes a planar portion 116 that is generally normal to the surface 119. By "generally normal" it is meant that ,an angle between the planar portion 116 and the surface 114 is greater than IS 45°. More preferably, the angle between the planar portion 116 and the surface 114 is greater than 85°.
Similarly, the second electrode 109 includes a planar portion 118 that is generally normal to the surface 114.
Preferably, the planar portion 116 is generally parallel to the planar portion 118.
It is preferred that the first electrode 102 and the second electrode 104 extend along an entire side of the gel member 110 to provide an improved sensitivity for detecting binding events. Generally, the first electrode 102 and the second electrode 104 can extend substantially along an entire side of the gel member 100, i.e. along at least 50$ of the side of the gel member 100.
The first electrode 102 can be electrically connected through the substrate 112 to a first contact - 120. The second electrode 104 can be electrically connected through the substrate 112 to a second contact 122.
FIG. 8 is a block diagram of another sensor in accordance with the present invention. The sensor comprises a first gel 130 which supports a first at least one molecular receptor 132. The sensor further comprises a first electrode 134 and a porous electrode 136 coupled to the first gel 130. The first electrode 134 and the porous electrode 136 can be either directly coupled, capacitively coupled, or inductively coupled to the first gel 130.
The sensor can further comprise a second gel 140 which supports a second at least one molecular receptor 142. In this case, the second gel 140 has a second electrode 144 and the porous electrode 136 coupled thereto. The second electrode 144 and the porous electrode 136 can be either directly coupled, capacitively coupled, or inductively coupled to the second gel 140.
Molecules to be detected by the sensor migrate through the porous electrode 136 to at least one of the first gel 130 and the second gel 140. Examples of the porous electrode 136 include, but are not limited to, a wire mesh through which molecules can migrate, an electrode having a porosity which allows molecules to migrate there through, and a perforated electrode having one or more holes which allows molecules to migrate there through.
A meter 146, such as the meter 32, is electrically connected to the first electrode 134 and the porous electrode 136. The meter 146 is used to electrically detect a binding event between at least one molecule 150 and the first at least one molecular receptor 132. The at least one molecule 150 migrates through the porous electrode 136 to the first at least one molecular receptor 132. Similarly, the meter 146 can be electrically connected to the second electrode 144 to electrically detect a binding event for the second at least one molecular receptor 142.
FIG. 9 is a side sectional view of an embodiment of the sensor of FIG. 8. The first electrode 134 and the second electrode 144 are supported by a substrate 152.
The substrate 152 includes a surface 154 with which the first electrode 134 and the second electrode 144 are integrated. The first electrode 134 and the second electrode 144 are generally planar.
The first gel 130 is supported by the first electrode 134. Preferably, the first electrode 134 is directly coupled to the first gel 130. In this case, the first electrode 134 can directly contact a surface of the first gel 130. Alternatively, the first electrode 134 can be capacitively coupled to the first gel 130. In this case, a dielectric material can be interposed between the first electrode 134 and a surface of the first gel 130.
The second gel 140 is supported by the second electrode 144. Preferably, the second electrode 144 is directly coupled to the second gel 140. In this case, the second electrode 144 can directly contact a surface of the second gel 140. Alternatively, the second electrode 144 can be capacitively coupled to the second gel 140. In this case, a dielectric material can be interposed between the second electrode 144 and a surface of the second gel 140.
The porous electrode 136 is supported by the first gel 130 and the second gel 140. As a result, the first gel 130 is interposed between the porous electrode 136 and the first electrode 134, and the second gel 140 is interposed between the porous electrode 136 and the second electrode 144.
Preferably, the porous electrode 136 is directly coupled to the first gel 130 and the second gel 140. In this case, the porous electrode 136 can directly contact ' a surface of the first gel 130 and a surface of the second gel 140. Alternatively, the porous electrode 136 can be capacitively coupled to the first gel 130 and the second gel 140. In this case, a dielectric material can be interposed between the porous electrode 136 and each of the first gel 130 and the second gel 140.
The first electrode 134 and the second electrode 144 are electrically connected to contacts 155 through the substrate 152.
Each of the herein-described sensors can be included in an array of sensors. The array can include a one-dimensional array of sensors, a two-dimensional array of sensors, or a three-dimensional array of sensors. External contacts for interfacing the sensors to the meters 32 and 196 can be located at one or more edges of the array. Alternatively, the external contacts can be located at a surface .opposite to a surface supporting the sensors and the gels.
A plurality of sensors described with reference to FIGS. 1 to 5, 13, and 19 can have their second electrodes interconnected to form a single ground electrode. Each sensor in the array is addressed-by the single ground electrode and an external contact associated with its first electrode.
FIG. 10 illustrates an embodiment of a one-dimensional array of sensors. A plurality of sensors 150 are integrated with a substrate 152. The sensors 150 are arranged as a linear array. A plurality of electrical contacts 155 are integrated with the substrate 1S2 near an edge 156. Each of the electrical contacts 155 is electrically connected to the first electrode of a respective one of the sensors 150. ' A ground plane 160 can electrically interconnect the second electrodes of the sensors 150 for sensors described with reference to FIGS. 1 to 5.
Alternatively, the ground plane 160 can comprise the S porous electrode 136 described with reference to FIGS. 8 and 9.
FIGS. 11 and 12 illustrate an embodiment of a two-dimensional array of sensors. A plurality of sensors 170 are integrated with a substrate 172 at a first 10 surface 174. The sensors 170 are arranged as a two-dimensional array. A plurality of electrical contacts 176 are located at an opposite surface 180 of the substrate 172. Each of the electrical contacts 176 is electrically connected to the first electrode of a 15 respective one of the sensors 170. Preferably, each of the electrical contacts 176 includes a pin oriented generally normal to the opposite surface 180 of the substrate 172.
A ground plane 182 can electrically interconnect the second electrodes of the sensors 170 for sensors described with reference to FIGS. 1 to 5.
Alternatively, the ground plane 182 can comprise the porous electrode 136 described With reference to FIGS. 8 and 9.
FIG. 13 is a top view of yet another embodiment of a sensor in accordance with the present invention. The sensor includes a gel member 190. The gel member 190 supports a plurality of molecular receptors (not specifically illustrated) such as those described with reference to FIG. 1. The gel member 190 is annular shaped. The gel member 190 can have a circular, annular shape as illustrated, or can have an alternative annular shape.
The sensor includes a first electrode 192 and a second electrode 194. From the top view, the first electrode 192 is substantially surrounded by the gel member 190, and the second electrode 194 substantially surrounds the gel member 190.
FIG. 14 is a side sectional view of the embodiment S of the sensor of FIG. 13. As illustrated, the gel member 190, the first electrode 192, and the second electrode 194 are supported by a substrate 196. The substrate 196 has a surface 200 that supports the gel member 190, a portion 202 of the first electrode 192, and a portion 204 of the second electrode 194.
The first electrode 192 is coupled to an inner periphery 206 of the gel member 190. The second electrode 194 is coupled to an outer periphery 210 of the gel member 190. The first electrode 192 and the second electrode 194 can be either directly coupled or indirectly coupled to the gel member 190 as described earlier.
As illustrated, the sensor can include a bottom contact 212 electrically coupled to the first electrode 192. Alternatively, the sensor can include a top contact to the first electrode 192. Similarly, the second electrode 194 can have an external contact accessible at either the top, the bottom, or sides of the substrate 196.
For each of the herein-described embodiments of sensors for electrically sensing molecular binding events, it is preferred that the electrodes be formed of metal. In general, however, the electrodes can be formed of a conductive material or a semiconductive material. It is preferred that the herein-described substrates be formed of an elastic polymer or a plastic.
In general, however, the substrates can be formed of a semiconductive material such as silicon or a dielectric material such as glass.
WO 99/18242 ~ PCT/US98I21251 -It is also noted that the gel members in each of the herein-described embodiments can be replaced by other receptor-supporting elements into which a reagent can diffuse. Examples of alternative elements include but are not limited to acrylamides, polypyrroles, polysaccharides, and other polymers.
Further, it is noted that embodiments of the present invention are applicable for biomolecular recognition in general. For example, the sensor can generally include ligand receptors for sensing hybridization, ligation, and analytes in solution.
Thus, there has been described herein several embodiments including preferred embodiments of sensors for electrically sensing molecular binding events for supported molecular receptors.
Because the various embodiments of the present invention electrically sense molecular binding events, they provide a significant improvement in that the use of radioactive markers and fluorescent markers is not required.
Additionally, various embodiments of the present invention as herein-described have an electrode embedded in each gel portion to provide better proximity to the molecular binding events.
Further, various embodiments of the present invention have a porous electrode coupled to each gel portion. The porous electrode is used to sense molecular binding events while allowing sample molecules to migrate there through.
It will be apparent to those skilled in the art that the disclosed invention may be modified in numerous ways and may assume many embodiments other than the preferred form specifically set out and described above.
Accordingly, it is intended by the appended claims to cover all modifications of the invention which fall within the true spirit and scope of the invention.
SUPPORTED MOLECULAR RECEPTORS
Technical Field The present invention relates to sensors for electrically sensing binding events with supported molecular receptors.
Background of the Invention U.S. Patent No. 5,552,270 to Khrapko et al.
describes a device for sequencing DNA by hybridization.
The device comprises an oligonucleotide array rigidly bound to a solid substrate. The oligonucleotide array consists of a multiplicity of gel portions separated from one another. Each gel portion contains one oligonucleotide of desired length.
Test DNA fragments are labeled with either a radioactive marker or a fluorescent marker. A solution including a buffer and the labeled test DNA fragments is applied to the device. The solution fully covers the gel portions containing immobilized oligonucleotides.
The labeled test DNA fragements hybridize with one or more of the oligonucleotides. After performing a washing step, hybridization events are detected by detecting the radioactive marker or-the fluorescent marker. A sequence associated with the test DNA
fragments is reconstructed by analyzing detection data.
lA
Two slides, one of which pretreated with Bind Silane and the other with Repel Silane (LKB) and lubricated with a thin layer of Triton X-100 are positioned at a distance from one another by means of 30 um thick spacers. The resulting clearance between the slides is filled with 8~
acrylamide solution, 30:1 N,N'-methylene bis-acrylamide, ammonium persulfate and TEMED, which is allowed to polymerize for 1 hour. As a result, a 30 um thick gel layer is formed between the slides, the dimensions of the layer being determined by the size of the slides. When the polymerization is complete, the upper slide is removed. The lower slide coated with a polyacrylamide layer is treated with 50~ hydrazine for 1 hour at room temperature. The bond between an oligonucleotide and polyacrylamide is stable enough to withstand at least 5 to 7 hybridization/washing cycles without any noticeable change in,its hybridizing properties. The half-life of the oligonucleotide-gel bond at 60° C. is 2 hours, and at 25° C., 36 hours.
It is desirable to detect the hybridization events without requiring that the test DNA fragments be labeled with radioactive markers or fluorescent markers.
Summary of the Invention The present invention seeks to overcome the disadvantages of the prior art associated with sensors for electrically sensing binding events for supported molecular receptors.
According to one aspect of the invention, a sensor is provided. The sensor comprises a receptor-supporting element into which a reagent is diffusable; at least one molecular receptor supported within the receptor-supporting element; and a first electrode embedded in the receptor-supporting element.
According to another aspect of the invention a sensor comprising: a first receptor-supporting element; a first at least one molecular receptor supported within the first receptor-supporting element; a first electrode coupled to the first receptor-supporting element; and a porous electrode coupled to the first receptor-supporting element.
According to another aspect of the invention a sensor comprising: a receptor-supporting element into which a reagent is diffusable; an annular-shaped electrode coupled to the receptor-supporting element; and an elongate electrode embedded in the receptor-supporting element.
According to a final aspect of the invention a sensor comprising: an annular-shaped, receptor-supporting element into which a reagent is diffusable; at least one molecular receptor supported within the annular-shaped, receptor-supporting element; and a first electrode and a second electrode coupled to the annular-shaped, receptor-supporting element.
The "Summary of the Invention " does not necessarily disclose all the inventive features. The inventions may reside in a sub-combination of the disclosed features.
Brief Description of the Drawings The invention is pointed out with particularity in the appended claims. However, other features of the invention will become more apparent and the invention will be best understood by referring to the following detailed description in conjunction with the accompanying drawings in which:
FIG. 1 is a block diagram of a sensor in accordance with the present invention;
FIG. 2 is a top view of a first embodiment of a sensor in accordance with the present invention;
FIG. 3 is a side sectional view of the embodiment of the sensor of FIG. 2;
FIG. 4 is a top view of a second embodiment of a sensor in accordance with the present invention;
FIG. 5 is a side sectional view of the embodiment of the sensor of FIG. 4;
FIG. 6 is a top view of a third embodiment of a sensor in accordance with the present invention;
FIG. 7 is a side sectional view of the embodiment of the sensor of FIG. 6;
FIG. 8 is a block diagram of another sensor in accordance with the present invention;
FIG. 9 is a side sectional view of an embodiment of the sensor of FIG. 8;
FIG. >.0 illustrates an embodiment of a one-dimensional array of sensors;
FIGS. 11 and 12 illustrate an embodiment of a two-dimensional array of sensors;
FTG. 13 is a top view of yet another embodiment of a sensor in accordance with the present invention; and FIG. 14 is a side sectional view of the embodiment of the sensor of FIG. 13.
wo ~nga42 rcrn~s9anms~ -Detailed Description of a Preferred Embodiment FIG. 1 is a block diagram of a sensor 18 in ' accordance with the present invention. The sensor 18 comprises a gel 20 which supports at least one molecular receptor 22. Preferably, the gel 20 supporting the at least one molecular receptor 22 is formed in accordance with U.S. Patent No. 5,552,270 to Khrapko et al.
;:
The at least one molecular receptor 22 is receptive to molecules having a predetermined and/or a preselected molecular structure. The at least one molecular receptor 22 can include either a biological molecule or a synthetic molecule having a specific affinity to its corresponding molecule. For example, each molecular receptor can include a chain of nucleotide bases to hybridize with a molecule having a complementary chain of nucleotide bases. In this case, each molecular receptor can include a DNA probe or a PNA probe for detecting a corresponding, complementary DNA base sequence, an RNA probe for detecting a corresponding, complementary RNA base sequence, or other DNA/RNA
analogues.
The sensor 18 includes a first electrode 24 embedded in the geI 20. The first electrode 24 is used to electrically sense hybridization or binding of at least one molecule 26 to the at least one molecular receptor 22. For example, the at least one molecule 26 can include a molecule having a plurality of nucleotide bases such as a DNA fragment or an RNA fragment to hybridize with the at least one molecular receptor 22.
Preferably, the first electrode 24 includes an elongate portion embedded in the gel 20. More preferably, the elongate portion is linear. ' Optionally, the sensor 1$ further includes a second electrode 30 coupled to the gel 20. The second electrode 30 can be either directly coupled, capacitively coupled, or inductively coupled to the gel 20. The second electrode 30 assists in electrically sensing the hybridization or binding of the at least one molecule 26 to the at least one molecular receptor 22.
Preferably, the second electrode 30 is disposed at a side of the gel 20. Additionally, the second electrode 30 can surround at least a portion of the gel and/or can surround at least a portion of the first electrode 24.
The second electrode 30 can include a cylindrical portion to surround or encircle the gel 20 and the first IS electrode 24. In this case, it is preferred that the first electrode 24 and the second electrode be generally coaxial. By "generally coaxial" it is meant that a first axis associated with the first electrode 24 is closer to being parallel to, rather than being 20 perpendicular to, a second axis associated with the second electrode 30.
A meter 32 is electrically connected to the first electrode 24 and the second electrode 30. The meter 32 is used to electrically detect a binding event between the at least one molecule 26 and the at least one molecular receptor 22. Preferably, the meter 32 includes an impedance meter, such as a capacitance meter or an inductance meter, to measure and/or detect a change in impedance between the first electrode 24 and the second electrode 30 resulting from the binding event. Alternatively, the meter 32 can measure and/or detect a charge associated with the binding event, or can measure and/or detect a resonance shift resulting from the binding event.
Generally, the meter 32 can detect a change in an electrical quantity (measured between the first electrode 24 and the second electrode 30) between two instances of time (e. g. a pre-binding time and a post-s binding time). Alternatively, the meter 32 can detect a change in an electrical quantity between the sensor 18 and a control sensor 34. The control sensor 34 can include a like gel having molecular receptors, a like first electrode, and a like second electrode as the sensor 18. The control sensor 34, however, is not exposed to the at least one molecule 26. The control sensor 34 is used as a calibration pixel for baseline subtraction.
FIG. 2 is a top view of a first embodiment of a sensor in accordance with the present invention. The sensor includes a gel member 40. The gel member 40 supports a plurality of molecular receptors (not specifically illustrated) such as those described with reference to FIG. 1. Although illustrated to have a rectangular cross section, the gel member 40 can have an alternatively-shaped cross section. Examples of alternatively-shaped cross sections include, but are not limited to, a polygonal cross section, an elliptical cross section, and a circular cross section.
The sensor includes a first electrode 42 and a second electrode 44. The first electrode 42 is embedded within the gel member 40. The second electrode 44 is coupled to a surface of the gel member 40.
Preferably, the first electrode 42 is directly coupled to the gel member 40. In this case, the first electrode 42 can directly contact an inner surface of the gel member 40. Alternatively, the first electrode 42 can be capacitively coupled to the gel member 40. In WO 99/18242 PCTlUS98/21251 this case, a dielectric material can be interposed between the first electrode 42 and a surface of the gel member 40.
Similarly, it is preferred that the second electrode 44 be directly coupled to the gel member 40.
In this case, the second electrode 44 can directly contact a surface of the gel member 40. Alternatively, the second electrode 44 can be capacitively coupled to the gel member 40. In this case, a sheet of dielectric material can be interposed between the second electrode 44 and a surface of the gel member 40.
The second electrode 44 defines an inner periphery 46 and an outer periphery 48. The inner periphery 46 defines an opening 50 that is completely covered by the gel member 40. The surface of the gel member 40 coupled to the second electrode 44 is bounded within the outer periphery 48.
Preferably, the inner periphery 46 and the outer periphery 48 are circular-shaped so that the second electrode 44 has the shape of a circular ring. It is noted, however, that the inner periphery 46 and the outer periphery 48 can be alternatively shaped to provide an alternative annular shape for the second electrode 44.
FIG. 3 is a side sectional view of the embodiment of the sensor of FIG. 2. As illustrated, the gel member 40, the first electrode 42, and the second electrode 44 are supported by a substrate 52. The substrate 52 has a surface 54 that supports the gel member 40. The second electrode 44 is integrated with the substrate 52 at the surface 54.
The first electrode 42 includes an elongate portion 56 embedded in the gel member 40. The elongate portion 56 has a length 58 greater than its width 60. Although the elongate portion 56 can be nonlinear, it is ' preferred that the elongate portion 56 be linear. The elongate portion 56 is oriented along an axis 62 transverse to the surface 54 of the substrate 52 and a surface 64 of the second electrode 44. The axis 62 extends through the opening SO of the second electrode 44.
It is preferred that the elongate portion 56 be generally normal to each of the aforementioned surfaces 54 and 64. By "generally normal" it is meant that an angle between the elongate portion 56 and a surface is greater than 45°. More preferably, the angle between the elongate portion 56 and each of the surfaces 54 and 64 is greater than 85°.
Preferably, the first electrode 42 extends through an entire dimension of the gel member 40 to provide an improved sensitivity for detecting binding events.
Generally, the first electrode 42 can extend substantially through an entire dimension of the gel member 40, i.e. through at least 50~ of a dimension of the gel member 40.
The first electrode 42 can be embedded in the gel member 40 using a variety of approaches. Using a first approach, the first electrode 42 includes a wire around which the gel member 40 is deposited. Using a second approach, the first electrode 42 includes a post fabricated by etching the substrate 52. The post is metallized before the gel member 40 is deposited.
Using a third approach, the substrate 52 is formed of a deformable material such as an elastic polymer or a plastic. A surface of the substrate 52 is metallized.
An elongate member such as a pin is applied to an opposing surface of the substrate 52. The pin deforms the substrate 52 to form the first electrode 42. In this case, the first electrode 42 may have a cone-like shape. The gel member 40 can be deposited either prior to or subsequent to the deformation of the substrate 52.
The first electrode 42 can be electrically connected through the substrate 52 to a first contact 64. Optionally, the second electrode 44 can be electrically connected through the substrate 52 to a second contact.
FIG. 4 is a top view of a second embodiment of a sensor in accordance with the present invention. The sensor includes a gel member 70. The gel member 70 supports a plurality of molecular receptors (not specifically illustrated) such as those described with reference to FIG. 1. Although illustrated to have a circular cross section, the gel member 70 can have an alternatively-shaped cross section. Examples of alternatively-shaped cross sections include, but are not limited to, a polygonal cross section.such as a rectangular cross section, and an elliptical cross section.
The sensor includes a first electrode 72 and a second electrode 74. The first electrode 72 is embedded within the gel member 70. The second electrode 74 is coupled to a surface of the gel member 70.
Preferably, the first electrode 72 is directly coupled to the gel member 70. In this case, the first electrode 72 can directly contact an inner surface of the gel member 70. Alternatively, the first electrode 72 can be capacitively coupled to the gel member 70. In this case, a dielectric material can be interposed between the first electrode 72 and a surface of the gel member 70.
Similarly, it is preferred that the second electrode 74 be directly coupled to the gel member 70. , In this case, the second electrode 74 can directly WO 99/18242 PCT/US98/2~251 -contact a side surface of the gel member 70.
Alternatively, the second electrode 74 can be capacitively coupled to the gel member 70. In this case, a sheet of dielectric material can be interposed between the second electrode 74 and the side surface of the gel member 70.
The second electrode 74 is cylindrically shaped to surround the gel member 70 and the first electrode 72.
Further, the second electrode 74 is coaxial with the first electrode 72.
FIG. 5 is a side sectional view of the embodiment of the sensor of FIG. 4. As illustrated, the gel member 70, the first electrode 72, and the second electrode 74 are supported by a substrate 82. The substrate 82 has a surface 84 that supports the gel member 70.
The first electrode 72 includes an elongate portion 86 embedded in the gel member 70. The elongate portion 86 has a length 88 greater than its width 90. Although the elongate portion 86 can be nonlinear, it is preferred that the elongate portion 86 be linear. The elongate portion 86 is oriented along an axis 92 transverse to the surface 84 of the substrate 82. The axis 92 also serves as an axis along which the second electrode 74 is~oriented.
It is preferred that the elongate portion 86 be generally normal to the surface 84. By "generally normal" it is meant that an angle between the elongate portion 86 and the surface 84 is greater than 45°. More preferably, the angle between the elongate portion 86 and the surface 84 is greater than 85°.
Preferably, the first electrode 72 and the second electrode 74 extend through an entire dimension of the gel member 70 to provide an improved sensitivity for detecting binding events. Generally, the first electrode 72 and the second electrode 74 can extend substantially through an entire dimension of the gel member 70, i.e. through at least 50~ of a dimension of the gel member 70.
It is noted that the first electrode 72 can be 5 formed and embedded in the gel member 70 using the approaches described with reference to FIG. 3.
The first electrode 72 can be electrically connected through the substrate 82 to a first contact 94. Optionally, the second electrode 74 can be 10 electrically connected through the substrate 82 to a second contact.
FIG. 6 is a top view of a third embodiment of a sensor in accordance with the present invention. The sensor includes a gel member 100. The gel member 100 supports a plurality of molecular receptors (not specifically illustrated) such as those described with reference to FIG. 1. Although illustrated to have a rectangular cross section, the gel member 100 can have an alternatively-shaped cross section. Examples of alternatively-shaped cross sections include, but are not limited to, a polygonal cross section, an elliptical cross section, and a circular cross section.
The sensor includes a first electrode 102 and a second electrode 104. The first electrode 102 is coupled to a first surface of the gel member 100. The second electrode 104 is coupled to a second surface of the gel member 100. Preferably, the first surface and the second surface are opposing surfaces of the gel member 100.
Preferably, the first electrode 102 and the second electrode 104 are directly coupled to the gel member 100. In this case, the first electrode 102 can directly contact the first surface and the second electrode 104 can contact the second surface. Alternatively, the first electrode 102 and the second electrode can be capacitively coupled to the geI member I00. In this case, a sheet of dielectric material can be interposed between the first electrode 102 and the first surface, and between the second electrode 109 and the second 5 surface.
FIG. 7 is a side sectional view of the embodiment of the sensor of FIG. 6. As illustrated, the gel member 100, the first electrode 102, and the second electrode 104 are supported by a substrate 112. The substrate 112 has a surface 119 that supports the gel member 100.
The first electrode 102 includes a planar portion 116 that is generally normal to the surface 119. By "generally normal" it is meant that ,an angle between the planar portion 116 and the surface 114 is greater than IS 45°. More preferably, the angle between the planar portion 116 and the surface 114 is greater than 85°.
Similarly, the second electrode 109 includes a planar portion 118 that is generally normal to the surface 114.
Preferably, the planar portion 116 is generally parallel to the planar portion 118.
It is preferred that the first electrode 102 and the second electrode 104 extend along an entire side of the gel member 110 to provide an improved sensitivity for detecting binding events. Generally, the first electrode 102 and the second electrode 104 can extend substantially along an entire side of the gel member 100, i.e. along at least 50$ of the side of the gel member 100.
The first electrode 102 can be electrically connected through the substrate 112 to a first contact - 120. The second electrode 104 can be electrically connected through the substrate 112 to a second contact 122.
FIG. 8 is a block diagram of another sensor in accordance with the present invention. The sensor comprises a first gel 130 which supports a first at least one molecular receptor 132. The sensor further comprises a first electrode 134 and a porous electrode 136 coupled to the first gel 130. The first electrode 134 and the porous electrode 136 can be either directly coupled, capacitively coupled, or inductively coupled to the first gel 130.
The sensor can further comprise a second gel 140 which supports a second at least one molecular receptor 142. In this case, the second gel 140 has a second electrode 144 and the porous electrode 136 coupled thereto. The second electrode 144 and the porous electrode 136 can be either directly coupled, capacitively coupled, or inductively coupled to the second gel 140.
Molecules to be detected by the sensor migrate through the porous electrode 136 to at least one of the first gel 130 and the second gel 140. Examples of the porous electrode 136 include, but are not limited to, a wire mesh through which molecules can migrate, an electrode having a porosity which allows molecules to migrate there through, and a perforated electrode having one or more holes which allows molecules to migrate there through.
A meter 146, such as the meter 32, is electrically connected to the first electrode 134 and the porous electrode 136. The meter 146 is used to electrically detect a binding event between at least one molecule 150 and the first at least one molecular receptor 132. The at least one molecule 150 migrates through the porous electrode 136 to the first at least one molecular receptor 132. Similarly, the meter 146 can be electrically connected to the second electrode 144 to electrically detect a binding event for the second at least one molecular receptor 142.
FIG. 9 is a side sectional view of an embodiment of the sensor of FIG. 8. The first electrode 134 and the second electrode 144 are supported by a substrate 152.
The substrate 152 includes a surface 154 with which the first electrode 134 and the second electrode 144 are integrated. The first electrode 134 and the second electrode 144 are generally planar.
The first gel 130 is supported by the first electrode 134. Preferably, the first electrode 134 is directly coupled to the first gel 130. In this case, the first electrode 134 can directly contact a surface of the first gel 130. Alternatively, the first electrode 134 can be capacitively coupled to the first gel 130. In this case, a dielectric material can be interposed between the first electrode 134 and a surface of the first gel 130.
The second gel 140 is supported by the second electrode 144. Preferably, the second electrode 144 is directly coupled to the second gel 140. In this case, the second electrode 144 can directly contact a surface of the second gel 140. Alternatively, the second electrode 144 can be capacitively coupled to the second gel 140. In this case, a dielectric material can be interposed between the second electrode 144 and a surface of the second gel 140.
The porous electrode 136 is supported by the first gel 130 and the second gel 140. As a result, the first gel 130 is interposed between the porous electrode 136 and the first electrode 134, and the second gel 140 is interposed between the porous electrode 136 and the second electrode 144.
Preferably, the porous electrode 136 is directly coupled to the first gel 130 and the second gel 140. In this case, the porous electrode 136 can directly contact ' a surface of the first gel 130 and a surface of the second gel 140. Alternatively, the porous electrode 136 can be capacitively coupled to the first gel 130 and the second gel 140. In this case, a dielectric material can be interposed between the porous electrode 136 and each of the first gel 130 and the second gel 140.
The first electrode 134 and the second electrode 144 are electrically connected to contacts 155 through the substrate 152.
Each of the herein-described sensors can be included in an array of sensors. The array can include a one-dimensional array of sensors, a two-dimensional array of sensors, or a three-dimensional array of sensors. External contacts for interfacing the sensors to the meters 32 and 196 can be located at one or more edges of the array. Alternatively, the external contacts can be located at a surface .opposite to a surface supporting the sensors and the gels.
A plurality of sensors described with reference to FIGS. 1 to 5, 13, and 19 can have their second electrodes interconnected to form a single ground electrode. Each sensor in the array is addressed-by the single ground electrode and an external contact associated with its first electrode.
FIG. 10 illustrates an embodiment of a one-dimensional array of sensors. A plurality of sensors 150 are integrated with a substrate 152. The sensors 150 are arranged as a linear array. A plurality of electrical contacts 155 are integrated with the substrate 1S2 near an edge 156. Each of the electrical contacts 155 is electrically connected to the first electrode of a respective one of the sensors 150. ' A ground plane 160 can electrically interconnect the second electrodes of the sensors 150 for sensors described with reference to FIGS. 1 to 5.
Alternatively, the ground plane 160 can comprise the S porous electrode 136 described with reference to FIGS. 8 and 9.
FIGS. 11 and 12 illustrate an embodiment of a two-dimensional array of sensors. A plurality of sensors 170 are integrated with a substrate 172 at a first 10 surface 174. The sensors 170 are arranged as a two-dimensional array. A plurality of electrical contacts 176 are located at an opposite surface 180 of the substrate 172. Each of the electrical contacts 176 is electrically connected to the first electrode of a 15 respective one of the sensors 170. Preferably, each of the electrical contacts 176 includes a pin oriented generally normal to the opposite surface 180 of the substrate 172.
A ground plane 182 can electrically interconnect the second electrodes of the sensors 170 for sensors described with reference to FIGS. 1 to 5.
Alternatively, the ground plane 182 can comprise the porous electrode 136 described With reference to FIGS. 8 and 9.
FIG. 13 is a top view of yet another embodiment of a sensor in accordance with the present invention. The sensor includes a gel member 190. The gel member 190 supports a plurality of molecular receptors (not specifically illustrated) such as those described with reference to FIG. 1. The gel member 190 is annular shaped. The gel member 190 can have a circular, annular shape as illustrated, or can have an alternative annular shape.
The sensor includes a first electrode 192 and a second electrode 194. From the top view, the first electrode 192 is substantially surrounded by the gel member 190, and the second electrode 194 substantially surrounds the gel member 190.
FIG. 14 is a side sectional view of the embodiment S of the sensor of FIG. 13. As illustrated, the gel member 190, the first electrode 192, and the second electrode 194 are supported by a substrate 196. The substrate 196 has a surface 200 that supports the gel member 190, a portion 202 of the first electrode 192, and a portion 204 of the second electrode 194.
The first electrode 192 is coupled to an inner periphery 206 of the gel member 190. The second electrode 194 is coupled to an outer periphery 210 of the gel member 190. The first electrode 192 and the second electrode 194 can be either directly coupled or indirectly coupled to the gel member 190 as described earlier.
As illustrated, the sensor can include a bottom contact 212 electrically coupled to the first electrode 192. Alternatively, the sensor can include a top contact to the first electrode 192. Similarly, the second electrode 194 can have an external contact accessible at either the top, the bottom, or sides of the substrate 196.
For each of the herein-described embodiments of sensors for electrically sensing molecular binding events, it is preferred that the electrodes be formed of metal. In general, however, the electrodes can be formed of a conductive material or a semiconductive material. It is preferred that the herein-described substrates be formed of an elastic polymer or a plastic.
In general, however, the substrates can be formed of a semiconductive material such as silicon or a dielectric material such as glass.
WO 99/18242 ~ PCT/US98I21251 -It is also noted that the gel members in each of the herein-described embodiments can be replaced by other receptor-supporting elements into which a reagent can diffuse. Examples of alternative elements include but are not limited to acrylamides, polypyrroles, polysaccharides, and other polymers.
Further, it is noted that embodiments of the present invention are applicable for biomolecular recognition in general. For example, the sensor can generally include ligand receptors for sensing hybridization, ligation, and analytes in solution.
Thus, there has been described herein several embodiments including preferred embodiments of sensors for electrically sensing molecular binding events for supported molecular receptors.
Because the various embodiments of the present invention electrically sense molecular binding events, they provide a significant improvement in that the use of radioactive markers and fluorescent markers is not required.
Additionally, various embodiments of the present invention as herein-described have an electrode embedded in each gel portion to provide better proximity to the molecular binding events.
Further, various embodiments of the present invention have a porous electrode coupled to each gel portion. The porous electrode is used to sense molecular binding events while allowing sample molecules to migrate there through.
It will be apparent to those skilled in the art that the disclosed invention may be modified in numerous ways and may assume many embodiments other than the preferred form specifically set out and described above.
Accordingly, it is intended by the appended claims to cover all modifications of the invention which fall within the true spirit and scope of the invention.
Claims (24)
1. A sensor comprising:
a receptor-supporting element into which a reagent is diffusable;
at least one molecular receptor supported within the receptor-supporting element;
and a first electrode embedded in the receptor-supporting element.
a receptor-supporting element into which a reagent is diffusable;
at least one molecular receptor supported within the receptor-supporting element;
and a first electrode embedded in the receptor-supporting element.
2. The sensor of claim 1 wherein the at least one molecular receptor is receptive to a sequence of a plurality of nucleotide bases.
3. The sensor of claim 1 wherein the first electrode includes an elongate portion embedded in the receptor-supporting element.
4. The sensor of claim 3 further comprising a substrate having a surface to support the receptor-supporting element, wherein the first electrode is generally normal to the surface of the substrate.
5. The sensor of claim 3 wherein the elongate portion is linear.
6. The sensor of claim 1 further comprising a second electrode coupled to the receptor-supporting element.
7. The sensor of claim 6 wherein the first electrode and the second electrode are generally coaxial.
8. The sensor of claim 6 wherein the second electrode surrounds at least a portion of the first electrode.
9. The sensor of claim 6 wherein the second electrode is cylindrical.
10. The sensor of claim 6 wherein the second electrode is disposed at a side of the receptor-supporting element.
11. The sensor of claim 6 wherein the second electrode is annular-shaped.
12. The sensor of claim 6 wherein the second electrode contacts the receptor-supporting element.
13. The sensor of claim 6 wherein the second electrode surrounds a portion of the receptor-supporting element.
14. The sensor of claim 1 wherein the receptor-supporting element includes a gel.
15. A sensor comprising:
a first receptor-supporting element;
a first at least one molecular receptor supported within the first receptor-supporting element;
a first electrode coupled to the first receptor-supporting element; and a porous electrode coupled to the first receptor-supporting element.
a first receptor-supporting element;
a first at least one molecular receptor supported within the first receptor-supporting element;
a first electrode coupled to the first receptor-supporting element; and a porous electrode coupled to the first receptor-supporting element.
16. The sensor of claim 15 further comprising:
a second receptor-supporting element;
a second at least one molecular receptor supported within the second receptor-supporting element; and a second electrode coupled to the second receptor-supporting element;
wherein the porous electrode is coupled to the second receptor-supporting element.
a second receptor-supporting element;
a second at least one molecular receptor supported within the second receptor-supporting element; and a second electrode coupled to the second receptor-supporting element;
wherein the porous electrode is coupled to the second receptor-supporting element.
17. The sensor of claim 15 wherein the porous electrode comprises a porous mesh.
18. The sensor of claim 15 wherein the first receptor-supporting element is disposed between the first electrode and the porous electrode.
19. The sensor of claim 15 wherein the first electrode and the porous electrode contact the first receptor-supporting element.
20. The sensor of claim 15 wherein the first receptor-supporting element comprises a material selected from the group consisting of a gel, an acrylamide, a polypyrrole, and a polysaccharide.
21. A sensor comprising:
a receptor-supporting element into which a reagent is diffusable;
an annular-shaped electrode coupled to the receptor-supporting element; and an elongate electrode embedded in the receptor-supporting element.
a receptor-supporting element into which a reagent is diffusable;
an annular-shaped electrode coupled to the receptor-supporting element; and an elongate electrode embedded in the receptor-supporting element.
22. A sensor comprising:
an annular-shaped, receptor-supporting element into which a reagent is diffusable;
at least one molecular receptor supported within the annular-shaped, receptor-supporting element; and a first electrode and a second electrode coupled to the annular-shaped, receptor-supporting element.
an annular-shaped, receptor-supporting element into which a reagent is diffusable;
at least one molecular receptor supported within the annular-shaped, receptor-supporting element; and a first electrode and a second electrode coupled to the annular-shaped, receptor-supporting element.
23. The sensor of claim 22 wherein the first electrode is coupled to an inner periphery of the annular-shaped, receptor-supporting element.
24. The sensor of claim 22 wherein the second electrode is coupled to an outer periphery of the annular-shaped, receptor-supporting element.
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| US08/946,620 US6048692A (en) | 1997-10-07 | 1997-10-07 | Sensors for electrically sensing binding events for supported molecular receptors |
| PCT/US1998/021251 WO1999018242A1 (en) | 1997-10-07 | 1998-10-06 | Sensors for electrically sensing binding events for supported molecular receptors |
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| CA002274245A Expired - Fee Related CA2274245C (en) | 1997-10-07 | 1998-10-06 | Sensors for electrically sensing binding events for supported molecular receptors |
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Families Citing this family (59)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6485905B2 (en) * | 1998-02-02 | 2002-11-26 | Signature Bioscience, Inc. | Bio-assay device |
| US6395480B1 (en) | 1999-02-01 | 2002-05-28 | Signature Bioscience, Inc. | Computer program and database structure for detecting molecular binding events |
| US6287776B1 (en) | 1998-02-02 | 2001-09-11 | Signature Bioscience, Inc. | Method for detecting and classifying nucleic acid hybridization |
| US20020177175A1 (en) * | 1998-02-02 | 2002-11-28 | Hefti John J. | Coplanar waveguide biosensor for detecting molecular or cellular events |
| US6287874B1 (en) | 1998-02-02 | 2001-09-11 | Signature Bioscience, Inc. | Methods for analyzing protein binding events |
| US6368795B1 (en) | 1998-02-02 | 2002-04-09 | Signature Bioscience, Inc. | Bio-assay device and test system for detecting molecular binding events |
| US6468785B1 (en) | 1999-02-19 | 2002-10-22 | New Mexico State University Technology Transfer Corporation | Doped conducting polymers applications and methods |
| US6942771B1 (en) * | 1999-04-21 | 2005-09-13 | Clinical Micro Sensors, Inc. | Microfluidic systems in the electrochemical detection of target analytes |
| US6238909B1 (en) * | 1999-05-04 | 2001-05-29 | Motorola, Inc. | Method and apparatus for obtaining electric field-enhanced bioconjugation |
| US20040185462A1 (en) * | 1999-08-06 | 2004-09-23 | Tum Gene, Inc. | Method of and detecting apparatus and detecting chip for single base substitution SNP and point mutation of genes |
| AU7708500A (en) * | 1999-09-22 | 2001-04-24 | Ge Healthcare Bio-Sciences Ab | Three-dimensional microarray system for parallel genotyping of single nucleotide polymorphisms |
| EP1146331B1 (en) * | 1999-10-20 | 2008-09-10 | Shigeori Takenaka | Gene detecting chip, detector, and detecting method |
| EP1238114A2 (en) * | 1999-12-09 | 2002-09-11 | Motorola, Inc. | Methods and compositions relating to electrical detection of nucleic acid reactions |
| US6518024B2 (en) | 1999-12-13 | 2003-02-11 | Motorola, Inc. | Electrochemical detection of single base extension |
| EP1255999A2 (en) * | 2000-02-01 | 2002-11-13 | Motorola, Inc. | Detection and differentiation of bacteria using electrical detection methods |
| US6824669B1 (en) | 2000-02-17 | 2004-11-30 | Motorola, Inc. | Protein and peptide sensors using electrical detection methods |
| DE60024264T2 (en) * | 2000-09-18 | 2006-08-17 | The Regents Of The University Of California, Oakland | Method and device for detecting molecular units |
| JP2006170615A (en) * | 2001-01-19 | 2006-06-29 | Shigeori Takenaka | Method of, device for, and chip of detecting gene |
| JP4505776B2 (en) | 2001-01-19 | 2010-07-21 | 凸版印刷株式会社 | Gene detection system, gene detection apparatus equipped with the same, detection method, and gene detection chip |
| US6749731B2 (en) * | 2001-01-31 | 2004-06-15 | Kyocera Corporation | Gene detection chip and detection device |
| JP3857928B2 (en) * | 2001-02-08 | 2006-12-13 | 京セラ株式会社 | Surface treatment method and surface-treated product of gold-plated body, method for producing gold-plated body, gold-plated body, and method for immobilizing sulfur-containing molecules |
| ES2441412T3 (en) * | 2001-03-09 | 2014-02-04 | Trovagene, Inc. | Conjugated probes and optical analyte detection |
| US7280014B2 (en) * | 2001-03-13 | 2007-10-09 | Rochester Institute Of Technology | Micro-electro-mechanical switch and a method of using and making thereof |
| US6627461B2 (en) | 2001-04-18 | 2003-09-30 | Signature Bioscience, Inc. | Method and apparatus for detection of molecular events using temperature control of detection environment |
| AU2002303933A1 (en) * | 2001-05-31 | 2002-12-09 | Rochester Institute Of Technology | Fluidic valves, agitators, and pumps and methods thereof |
| WO2003042396A2 (en) * | 2001-06-11 | 2003-05-22 | Genorx, Inc. | Electronic detection of biological molecules using thin layers |
| US6461808B1 (en) | 2001-06-12 | 2002-10-08 | Signature Bioscience, Inc. | Pipette-loaded bioassay assembly for detecting molecular or cellular events |
| JP2002372533A (en) * | 2001-06-13 | 2002-12-26 | Kiwamu Akagi | Examination method of blood, examination chip, and examination device |
| US20040166593A1 (en) * | 2001-06-22 | 2004-08-26 | Nolte David D. | Adaptive interferometric multi-analyte high-speed biosensor |
| US20030032000A1 (en) * | 2001-08-13 | 2003-02-13 | Signature Bioscience Inc. | Method for analyzing cellular events |
| US20040023236A1 (en) * | 2001-10-26 | 2004-02-05 | Potter Michael D. | Chemical and biological hazard sensor system and methods thereof |
| US7378775B2 (en) * | 2001-10-26 | 2008-05-27 | Nth Tech Corporation | Motion based, electrostatic power source and methods thereof |
| US7211923B2 (en) * | 2001-10-26 | 2007-05-01 | Nth Tech Corporation | Rotational motion based, electrostatic power source and methods thereof |
| US20030175947A1 (en) * | 2001-11-05 | 2003-09-18 | Liu Robin Hui | Enhanced mixing in microfluidic devices |
| US7091412B2 (en) * | 2002-03-04 | 2006-08-15 | Nanoset, Llc | Magnetically shielded assembly |
| US20040014078A1 (en) * | 2002-02-06 | 2004-01-22 | James Xia | Compositions and methods for rolling circle amplification |
| US9126165B1 (en) | 2002-04-24 | 2015-09-08 | The University Of North Carolina At Greensboro | Nucleic acid arrays to monitor water and other ecosystems |
| US8048623B1 (en) | 2002-04-24 | 2011-11-01 | The University Of North Carolina At Greensboro | Compositions, products, methods and systems to monitor water and other ecosystems |
| US8383342B2 (en) | 2002-04-24 | 2013-02-26 | The University Of North Carolina At Greensboro | Compositions, products, methods and systems to monitor water and other ecosystems |
| US7011948B2 (en) * | 2002-07-17 | 2006-03-14 | Mds Sciex | Detection of ligand-antiligand complex formation by electromagnetically detectable bulk property measurement |
| US7932098B2 (en) * | 2002-10-31 | 2011-04-26 | Hewlett-Packard Development Company, L.P. | Microfluidic system utilizing thin-film layers to route fluid |
| US7706984B2 (en) * | 2003-03-11 | 2010-04-27 | The Regents Of The University Of California | Method and device for identifying molecular species |
| WO2005005979A1 (en) * | 2003-07-14 | 2005-01-20 | Mds Inc. , Doing Business As Mds Sciex | Label-free method for classification and characterization of cellular events |
| US7217582B2 (en) * | 2003-08-29 | 2007-05-15 | Rochester Institute Of Technology | Method for non-damaging charge injection and a system thereof |
| US7287328B2 (en) * | 2003-08-29 | 2007-10-30 | Rochester Institute Of Technology | Methods for distributed electrode injection |
| US8581308B2 (en) * | 2004-02-19 | 2013-11-12 | Rochester Institute Of Technology | High temperature embedded charge devices and methods thereof |
| US20060118758A1 (en) * | 2004-09-15 | 2006-06-08 | Xingwu Wang | Material to enable magnetic resonance imaging of implantable medical devices |
| US20070023643A1 (en) * | 2005-02-01 | 2007-02-01 | Nolte David D | Differentially encoded biological analyzer planar array apparatus and methods |
| US7910356B2 (en) * | 2005-02-01 | 2011-03-22 | Purdue Research Foundation | Multiplexed biological analyzer planar array apparatus and methods |
| US7663092B2 (en) | 2005-02-01 | 2010-02-16 | Purdue Research Foundation | Method and apparatus for phase contrast quadrature interferometric detection of an immunoassay |
| US20060216203A1 (en) * | 2005-03-28 | 2006-09-28 | Mds Sciex (Us) A Division Of Mds Pharma Services (Us) Inc. | Multiwell sample plate with integrated impedance electrodes and connection scheme |
| US20070074731A1 (en) * | 2005-10-05 | 2007-04-05 | Nth Tech Corporation | Bio-implantable energy harvester systems and methods thereof |
| WO2007131103A2 (en) * | 2006-05-03 | 2007-11-15 | Quadraspec, Inc. | Direct printing of patterned hydrophobic wells |
| US20080230605A1 (en) * | 2006-11-30 | 2008-09-25 | Brian Weichel | Process and apparatus for maintaining data integrity |
| US7522282B2 (en) * | 2006-11-30 | 2009-04-21 | Purdue Research Foundation | Molecular interferometric imaging process and apparatus |
| US20080144899A1 (en) * | 2006-11-30 | 2008-06-19 | Manoj Varma | Process for extracting periodic features from images by template matching |
| US7659968B2 (en) * | 2007-01-19 | 2010-02-09 | Purdue Research Foundation | System with extended range of molecular sensing through integrated multi-modal data acquisition |
| WO2008118934A1 (en) * | 2007-03-26 | 2008-10-02 | Purdue Research Foundation | Method and apparatus for conjugate quadrature interferometric detection of an immunoassay |
| AU2010275448B2 (en) | 2009-07-23 | 2014-03-06 | Chromatin, Inc. | Sorghum centromere sequences and minichromosomes |
Family Cites Families (9)
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|---|---|---|---|---|
| JPS63228066A (en) * | 1986-04-30 | 1988-09-22 | Toray Ind Inc | Method and device for detection |
| AU617687B2 (en) * | 1987-07-27 | 1991-12-05 | Ambri Limited | Receptor membranes |
| JP2682859B2 (en) * | 1987-07-27 | 1997-11-26 | コモンウェルス サイエンティフィック アンド インダストリアル リサーチ オーガニゼーション | Receptor membrane |
| CS274231B1 (en) * | 1988-12-05 | 1991-04-11 | Jan Rndr Krejci | Regenerable enzyme sensor with exchangeable membrane system |
| US5156810A (en) * | 1989-06-15 | 1992-10-20 | Biocircuits Corporation | Biosensors employing electrical, optical and mechanical signals |
| US5605662A (en) * | 1993-11-01 | 1997-02-25 | Nanogen, Inc. | Active programmable electronic devices for molecular biological analysis and diagnostics |
| IL103674A0 (en) * | 1991-11-19 | 1993-04-04 | Houston Advanced Res Center | Method and apparatus for molecule detection |
| US5846708A (en) * | 1991-11-19 | 1998-12-08 | Massachusetts Institiute Of Technology | Optical and electrical methods and apparatus for molecule detection |
| US5527703A (en) * | 1994-05-25 | 1996-06-18 | Merck & Co., Inc. | DNA encoding glutamate gated chloride channels |
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1997
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- 1998-10-06 WO PCT/US1998/021251 patent/WO1999018242A1/en not_active Application Discontinuation
- 1998-10-06 AU AU10727/99A patent/AU717517B2/en not_active Ceased
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| US6048692A (en) | 2000-04-11 |
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| EP0972085A4 (en) | 2000-04-26 |
| AU1072799A (en) | 1999-04-27 |
| CA2274245A1 (en) | 1999-04-15 |
| EP0972085A1 (en) | 2000-01-19 |
| AU717517B2 (en) | 2000-03-30 |
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