Optimized capacitive sensor for chemical analysis and measurement
First Claim
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1. A device for detecting the presence of an analyte in a fluid having an aqueous solvent, said device comprising:
- a sensing capacitor including;
a substrate having a first conductor and a second conductor spaced a distance from said first conductor,an electrically insulating layer covering said first and second conductors, said electrically insulating layer defining a surface,a binding agent selected from the group consisting of antigens, haptens, bioreceptors and antibodies capable of biospecifically binding with the analyte,a linking molecule adapted for and covalently bonding said binding agent to said surface and extending said binding agent a distance from said surface to minimize steric hindrance between the analyte and the surface; and
,a circuit means, electrically coupled to said sensing capacitor, responsive to changes in capacitance between said first and second conductors.
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Abstract
An apparatus for detecting the presence and/or measuring the concentration of an analyte in the fluid medium is disclosed. The apparatus relies on biospecific binding between a biochemical binding system and the analyte to change the dielectric properties of a capacitive affinity sensor. The biological affinity sensor is optimized by: (1) adjusting the thickness and dielectric properties of a passivation layer to generally match the impedance of the biological binding system; and (2) minimize the double layer capacitance so that bulk capacitance changes associated with the biological binding system are maximized.
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Citations
16 Claims
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1. A device for detecting the presence of an analyte in a fluid having an aqueous solvent, said device comprising:
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a sensing capacitor including; a substrate having a first conductor and a second conductor spaced a distance from said first conductor, an electrically insulating layer covering said first and second conductors, said electrically insulating layer defining a surface, a binding agent selected from the group consisting of antigens, haptens, bioreceptors and antibodies capable of biospecifically binding with the analyte, a linking molecule adapted for and covalently bonding said binding agent to said surface and extending said binding agent a distance from said surface to minimize steric hindrance between the analyte and the surface; and
,a circuit means, electrically coupled to said sensing capacitor, responsive to changes in capacitance between said first and second conductors. - View Dependent Claims (2, 7)
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3. A device for detecting the present of an analyte in a fluid having an aqueous solvent, said device comprising:
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a sensing capacitor including; a substrate having a first conductor and a second conductor spaced a distance from said first conductor, a binding agent selected from the group consisting of antigens, adapters, bioreceptors and antibodies capable of biospecifically binding with the analyte, an electrically insulating layer covering said first and second conductors, said electrically insulating layer defining a surface, wherein the composition and thickness of said insulating layer is selected to produce a series capacitance smaller than the double layer series capacitance and approaching the series capacitance produced by the binding agent, a linking molecule adapted for and covalently bonding said binding agent to said surface; and
,a circuit means, electrically coupled to said sensing capacitor, responsive to changes in capacitance between said first and second conductors. - View Dependent Claims (4, 5, 6)
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8. The device for detecting the presence of an analyte in a liquid, said device comprising:
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a sensing capacitor including, a substrate having a first conductor and a second conductor spaced a distance from said first conductor, an electrically insulating layer covering said first and second conductors, said electrically insulating layer defining a surface, a first organic compound having a biospecific binding site, a linking molecule adapted for and covalently bonding said first organic compound to said surface, and extending said first organic compound a distance from said surface to minimize steric hinderance between the analyte and the surface, a binding agent composed essentially of an organic compound selected from the group consisting of antibodies, lectins, enzymes, and neural receptors and being reversibly bound to said first organic compound, said binding agent biospecifically reactive with both said first organic compound and said analyte, wherein exposure of said binding agent to a liquid containing analyte causes formation of a binding agent/analyte complex through competitive binding, said binding agent/analyte complex being free to diffuse from said surface; and
,a circuit means, electrically coupled to said sensing capacitor, responsive to changes in capacitance between said first and second conductors. - View Dependent Claims (9, 14, 15, 16)
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10. A device for detecting the presence of an analyte in a liquid, said device comprising:
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a sensing capacitor including, a substate having a first conductor and a second conductor spaced a distance from said first conductor, an electrically insulating layer covering said first and second conductors, said electrically insulating layer defining a surface, wherein the composition and thickness of said insulating layer is selected to produce a series capacitance smaller than the double layer series capacitance, a first organic compound having a biospecific binding site, a linking molecule adapted for and covalently bonding said first organic compound to said surface, a binding agent composed essentially of an organic compound selected from the group consisting of antibodies, lectins, enzymes, and neural receptors and neural receptors and being reversibly bound to said first organic compound, said binding agent biospecifically reactive with both said first organic compound and said analyte, wherein exposure of said binding agent to a liquid containing analyte causes formation of a binding agent/analyte complex through competitive binding, said binding agent/analyte complex being free to diffuse from said surface; and
,a circuit means, electrically coupled to said sensing capacitor, responsive to changes in capacitance between said first and second conductors. - View Dependent Claims (11, 12, 13)
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Specification