Abstract: A diagnostic kit, method, and apparatus for electrochemically determining the presence or concentration of an analyte in a sample. A mixture is formed which includes the sample, an enzyme acceptor polypeptide, an enzyme donor polypeptide, and a labeled substrate. The enzyme donor polypeptide is capable of combining with the enzyme acceptor polypeptide to form an active enzyme complex. The formation of such the active enzyme complex is responsive to the presence or concentration of the analyte in the fluid sample. The active enzyme hydrolyzes the labeled substrate, resulting in the generation of an electroactive label, which can then be oxidized at the surface of an electrode. A current resulting from the oxidation of the electroactive compound can be measured and correlated to the concentration of the analyte in the sample.

Abstract: A diagnostic kit, method, and apparatus for electrochemically determining the presence or concentration of an analyte in a sample. A mixture is formed which includes the sample, an enzyme acceptor polypeptide, an enzyme donor polypeptide, and a labeled substrate. The enzyme donor polypeptide is capable of combining with the enzyme acceptor polypeptide to form an active enzyme complex. The formation of such the active enzyme complex is responsive to the presence or concentration of the analyte in the fluid sample. The active enzyme hydrolyzes the labeled substrate, resulting in the generation of an electroactive label, which can then be oxidized at the surface of an electrode. A current resulting from the oxidation of the electroactive compound can be measured and correlated to the concentration of the analyte in the sample.

Abstract: A new group of Os(II) and Os(III) compounds useful as redox mediators in electrochemical biosensors. These compounds have 1) low oxidation potential, 2) fast reaction kinetics between the electroactive center of an enzyme and the compound, 3) slow oxidation of osmium by oxygen, and 4) excellent solubility in aqueous medium. These mediators are particularly useful as a component of a reagent used in an electrochemical biosensor, wherein the biosensor is useful for measuring analytes from a biological fluid, such as blood.

Abstract: A new group of Os(II) and Os(III) compounds useful as redox mediators in electrochemical biosensors. These compounds have 1) low oxidation potential, 2) fast reaction kinetics between the electroactive center of an enzyme and the compound, 3) slow oxidation of osmium by oxygen, and 4) excellent solubility in aqueous medium. These mediators are particularly useful as a component of a reagent used in an electrochemical biosensor, wherein the biosensor is useful for measuring analytes from a biological fluid, such as blood.

Abstract: An immunoassay diagnostic kit, method, and apparatus for electrochemically determining the concentration of an analyte in a sample. A mixture is formed which includes the sample, an enzyme-acceptor polypeptide, an enzyme-donor polypeptide linked to an analyte analog (enzyme-donor polypeptide conjugate), a labeled substrate, and an antibody specific for the analyte to be measured. The analyte and the enzyme-donor polypeptide conjugate competitively bind to the antibody. When the enzyme-donor polypeptide conjugate is not bound to antibody, it will spontaneously combine with the enzyme acceptor polypeptide to form an active enzyme complex. The active enzyme hydrolyzes the labeled substrate, resulting in the generation of an electroactive label, which can then be oxidized at the surface of an electrode. A current resulting from the oxidation of the electroactive compound can be measured and correlated to the concentration of the analyte in the sample.