Genetics International, Inc.

Elliot V Plotkin

Hugh A Hill

Irving J Higgins

This invention relates to equipment and methods for detecting the presence of, measuring the amount of, and/or monitoring the level of, one or more selected components in a liquid mixture, employing an electrode sensing system. We have discovered that a class of mediating compounds has extremely useful properties for mediating the transfer of charge between enzyme-catalyzed reactions and electrode surfaces (15) in electrode sensing systems. Specifically, the specification discloses as electrode sensor mediators, organometallic compounds composed of at least two organic rings, each of which has at least two double bonds in a conjugated relationship; a metal atom is in electron-sharing contact with those rings. An enzyme capable of catalyzing a reaction at a rate representative of the selected compound concentration is in contact with an assay mixture, and the mediator compound transfers charge between the enzyme and the conductive surface of the electrode at a rate representative of the enzyme catalyzed reaction rate.

Sensor for components of a liquid mixture

A sensor electrode to detect one or more components in a liquid mixture comprises an electrically conductive material having at least an an external surface, the combination of an enzyme catalytic for a reaction of the desired component, and a mediator compound which transfers electrons from the enzyme to the electrode when such catalytic activity takes place. It can be used as an in vivo glucose sensor either with a silver electrode coated with e.g. glucose oxidase and a polyviologen as the mediators, or with a particulate carbon electrode, glucose oxidase and chloranil or fluoranil as mediator. Another system is to use bacterial glucose dehydrogenase or glucose oxidase as the enzyme and/or ferrocene or a ferrocene derivative as the mediators compound to give electrodes with improved linearity, speed of response and insensitivity to oxygen.

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Bedford, United Kingdom

Elliot V Plotkin