Homogeneous amperometric immunoassay
First Claim
1. A method for determining the concentration of an analyte present in a sample of biological fluid contained in an electrochemical cell equipped with a set of electrodes, said method comprising the steps of:
- a) forming an electroactive complex containing an antigenic analyte chemically bonded to a carrier molecule, said carrier molecule also being chemically bonded to an electroactive molecule capable of transferring a charge to an electrode;
b) adding the biological fluid, predetermined amounts of the electroactive complex, and an antibody to the analyte to the cell;
c) applying a voltage across the electrodes and measuring the current in the fluid at different voltage levels to form a voltage/current relationship for the sample fluid; and
d) comparing the voltage/current relationship for the sample fluid with standard voltage/current relationships generated using known amounts of analytes to determine the concentration of analyte present in the sample.
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Abstract
A method is described for measuring the amount of analyte present in a sample containing the analyte using a homogeneous amperometric immunoassay. The analyte is chemically bonded to a suitable carrier molecule, which is also chemically bonded to an electroactive molecule. The electroactive molecule, such as ferrocene carboxylic acid, contains a redox center which is capable of transferring a charge to an electrode. A preferred carrier molecule is bovine serum albumin (BSA), while suitable analytes include digoxin, theophylline and HCG. The immunoassay is conveniently performed by applying a voltage to a set of electrodes.
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Citations
20 Claims
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1. A method for determining the concentration of an analyte present in a sample of biological fluid contained in an electrochemical cell equipped with a set of electrodes, said method comprising the steps of:
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a) forming an electroactive complex containing an antigenic analyte chemically bonded to a carrier molecule, said carrier molecule also being chemically bonded to an electroactive molecule capable of transferring a charge to an electrode; b) adding the biological fluid, predetermined amounts of the electroactive complex, and an antibody to the analyte to the cell; c) applying a voltage across the electrodes and measuring the current in the fluid at different voltage levels to form a voltage/current relationship for the sample fluid; and d) comparing the voltage/current relationship for the sample fluid with standard voltage/current relationships generated using known amounts of analytes to determine the concentration of analyte present in the sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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- 11. An electroactive complex comprising at least one antigenic analyte chemically bonded to a carrier molecule, said carrier molecule also being chemically bonded to at least one electroactive molecule.
Specification