Conductive sensors and their use in diagnostic assays

Claim 2

A conductive sensor for assaying a test sample for the presence or concentration of a predetermined analyte, said predetermined analyte capable of interacting with an oxidase enzyme, said conductive sensor comprising: a) a layer of a host matrix permeable to the predetermined analyte, said host matrix layer having homogeneously incorporated therein an oxidase enzyme capable of interacting with the predetermined analyte, a compound having peroxidase activity and a dopant compound precursor, and wherein the predetermined analyte, the oxidase enzyme, the compound having peroxidase activity and the dopant compound precursor interact to generate a dopant compound; b) a layer of a conducting polymer in contact with the host matrix such that at least a portion of the dopant compound generated in the host matrix layer migrates to and oxidatively dopes the conducting polymer layer; and c) means operatively connected to the conducting polymer layer for measuring a change in conductivity of the conducting polymer layer.

Claim 3

The conductive sensor of Claim 1, wherein the host matrix layer comprises gelatin, chitosan, silk fibroin, collagen, poly(2-hydroxyethylmethacrylate), polyacrylamide or a combination thereof.

Claim 4

The conductive sensor of Claim 1, wherein the compound having peroxidase activity is horseradish peroxidase, lactoperoxidase, microperoxidase or combinations thereof.

Claim 5

The conductive sensor of Claim 1, wherein the conducting polymer layer comprises a poly-(alkylthiopene), a polythiophene, a poly(thienylene vinylene), a poly(furylene vinylene), a polypyrrole, a polyfuran, a polyaniline or a combination thereof.

Claim 6

A conductive sensor for assaying a biological fluid for the presence or concentration of a predetermined analyte, said predetermined analyte capable of interacting with an oxidase enzyme, said conductive sensor comprising: a) a layer of a host matrix comprising gelatin, chitosan or a combination thereof and having a thickness of from about 0.2 µ to about 5 µ, said host matrix layer permeable to the predetermined analyte and said host matrix layer having homogeneously incorporated therein an oxidase enzyme capable of interacting with the predetermined analyte, a peroxidase enzyme or a molybdenum(VI) transition metal catalyst, and iodide ion, and wherein the predetermined analyte, the oxidase enzyme, the peroxidase enzyme or the molybdenum(VI) catalyst, and the iodide ion interact to generate molecular iodine; b) a layer of a conducting polymer having a thickness of from about 100A to about 2000A in contact with the host matrix layer such that at least a portion of the molecular iodine generated in the host matrix layer can migrate to and oxidatively dope the conducting polymer layer; and c) a microelectrode assembly in contact with the conducting polymer layer, said microelectrode assembly adapted to sense a change in conductivity of the conducting polymer layer in response to the oxidative doping of the conducting polymer layer by the molecular iodine.

Claim 7

A conductive sensor for assaying a biological fluid for the presence or concentration of a predetermined analyte, said predetermined analyte capable of interacting with an oxidase enzyme, said conductive sensor comprising: a) a layer of a host matrix comprising gelatin, chitosan or a combination thereof and having a thickness of from about 0.2 µ to about 5 µ, said host matrix layer permeable to the predetermined analyte and said host matrix layer having homogeneously incorporated therein an oxidase enzyme capable of interacting with the predetermined analyte, a peroxidase enzyme or a molybdenum(VI) transition metal catalyst, and iodide ion, and wherein the predetermined analyte, the oxidase enzyme, the peroxidase enzyme or the molybdenum(VI) catalyst, and the iodide ion interact to generate molecular iodine; b) a layer of a conducting polymer having a thickness of from about 100A to about 2000A in contact with the host matrix layer such that at least a portion of the molecular iodine generated in the host matrix layer can migrate to and oxidatively dope the conducting polymer layer; and c) a microelectrode assembly in contact with the conducting polymer layer, said microelectrode assembly adapted to sense a change in conductivity of the conducting polymer layer in response to the oxidative doping of the conducting polymer layer by the molecular iodine.

Claim 8

A conductive sensor for assaying a test sample for the presence or concentration of a predetermined analyte, said predetermined analyte capable of interacting with an oxidase enzyme, said conductive sensor comprising: a) a semipermeable membrane capable of effectively separating cellular material and the interfering components from the test sample and capable of allowing the predetermined analyte to permeate through the semipermeable membrane at a uniform rate; b) a layer of a host matrix in contact with the semipermeable membrane and permeable to the predetermined analyte, said host matrix layer having homogeneously incorporated therein an oxidase enzyme capable of interacting with the predetermined analyte, a compound having peroxidase activity and a dopant compound precursor, wherein the predetermined analyte, the oxidase enzyme, the compound having peroxidase activity and the dopant compound precursor interact to generate a dopant compound; c) a layer of a conducting polymer in contact with the host matrix layer such that at least a portion of the dopant compound generated in the host matrix layer migrates to and oxidatively dopes the conducting polymer layer; and d) means operatively connected to the conducting polymer layer for measuring a change in conductivity of the conducting polymer layer.

Claim 9

A conductive sensor for assaying a test sample for the presence or concentration of a predetermined analyte, said predetermined analyte capable of interacting with an oxidase enzyme, said conductive sensor comprising: a) a semipermeable membrane capable of effectively separating cellular material and the interfering components from the test sample and capable of allowing the predetermined analyte to permeate through the semipermeable membrane at a uniform rate; b) a layer of a host matrix in contact with the semipermeable membrane and permeable to the predetermined analyte, said host matrix layer having homogeneously incorporated therein an oxidase enzyme capable of interacting with the predetermined analyte, a compound having peroxidase activity and a dopant compound precursor, wherein the predetermined analyte, the oxidase enzyme, the compound having peroxidase activity and the dopant compound precursor interact to generate a dopant compound; c) a layer of a conducting polymer in contact with the host matrix layer such that at least a portion of the dopant compound generated in the host matrix layer migrates to and oxidatively dopes the conducting polymer layer; and d) means operatively connected to the conducting polymer layer for measuring a change in conductivity of the conducting polymer layer.

Claim 10

A conductive sensor for assaying a biological fluid for the presence or concentration of a predetermined analyte, said predetermined analyte capable of interacting with an oxidase enzyme, and said conductive sensor comprising: a) an elastomer-based semipermeable membrane having a thickness of from about 5 µ to about 10 µ, said elastomer-based semipermeable membrane capable of effectively separating cellular material and interfering components from the biological fluid and capable of allowing the predetermined analyte to permeate through the semipermeable membrane at a uniform rate; b) a layer of a host matrix, comprising gelatin, chitosan or a combination thereof and having a thickness of from about 0.2 µ to about 5 µ, in contact with the semipermeable membrane, said host matrix layer permeable to the predetermined analyte and said host matrix layer having homogeneously incorporated therein an oxidase enzyme capable of interacting with the predetermined analyte, a peroxidase enzyme or a molybdenum(VI) transition metal catalyst, and iodide ion, wherein the predetermined analyte, the oxidase enzyme, the peroxidase enzyme or the molybdenum(VI) catalyst, and the iodide ion interact to generate molecular iodine; c) a layer of a conducting polymer having a thickness of from about 100A to about 2000A in contact with the host matrix layer such that at least a portion of the molecular iodine generated in the host matrix layer migrates to and oxidatively dopes the conducting polymer layer; and d) a microelectrode assembly in contact with the conducting polymer layer, said microelectrode assembly adapted to sense a change in conductivity of the conducting polymer layer in response to the oxidative doping of the conducting polymer layer by the molecular iodine.

Claim 11

A conductive sensor for assaying a biological fluid for the presence or concentration of a predetermined analyte, said predetermined analyte capable of interacting with an oxidase enzyme, and said conductive sensor comprising: a) an elastomer-based semipermeable membrane having a thickness of from about 5 µ to about 10 µ, said elastomer-based semipermeable membrane capable of effectively separating cellular material and interfering components from the biological fluid and capable of allowing the predetermined analyte to permeate through the semipermeable membrane at a uniform rate; b) a layer of a host matrix, comprising gelatin, chitosan or a combination thereof and having a thickness of from about 0.2 µ to about 5 µ, in contact with the semipermeable membrane, said host matrix layer permeable to the predetermined analyte and said host matrix layer having homogeneously incorporated therein an oxidase enzyme capable of interacting with the predetermined analyte, a peroxidase enzyme or a molybdenum(VI) transition metal catalyst, and iodide ion, wherein the predetermined analyte, the oxidase enzyme, the peroxidase enzyme or the molybdenum(VI) catalyst, and the iodide ion interact to generate molecular iodine; c) a layer of a conducting polymer having a thickness of from about 100A to about 2000A in contact with the host matrix layer such that at least a portion of the molecular iodine generated in the host matrix layer migrates to and oxidatively dopes the conducting polymer layer; and d) a microelectrode assembly in contact with the conducting polymer layer, said microelectrode assembly adapted to sense a change in conductivity of the conducting polymer layer in response to the oxidative doping of the conducting polymer layer by the molecular iodine.