Lifescan Corporation

Usf Filtration & Separations Group Inc.

Commonwealth Scientific and Industrial Research Organisation

Oddvar Johansen

Thomas William Beck

Alastair McIndoe Hodges

Ian Andrew Maxwell

Alastair McIndoc Hodges

Ronald Christopher Chatelier

Ernst Hammel

Graham M Johnson

John Gerard Steele

Liming Dai

Xinhe Tang

Wolfgang H Sasse

Albert Mau

Shaoming Huang

Alastair Mcindoe Hodges

Albert W Mau

Jean D Swift

Johnathon Hodgkin

Devices and methods are provided for determining the concentration of a reduced form of a redox species. For example, a device can include a working electrode and a counter electrode spaced by a predetermined distance so that reaction produces from the counter electrode arrive at the working electrode. An electric potential difference can be applied between the electrodes, and the potential of the working electrode can be selected such that the rate of electro-oxidation of the reduced form of the species is diffusion controlled. Current as a function of time can be determined, the magnitude of the steady state current can be estimated, and a value indicative of the diffusion coefficient and/or of the concentration of the reduced form of the species can be obtained from the change in current with time and the magnitude of the steady state current. Other embodiments of apparatuses, devices, and methods are also provided.

Electrochemical cell

This invention relates to a biosensor and more particularly to an electrochemical biosensor for determining the concentration of an analyte in a carrier. The invention is particularly useful for determining the concentration of glucose in blood and is described herein with reference to that use but it should be understood that the invention is applicable to other analytic determinations.

A hollow electrochemical cell is provided. In one exemplary embodiment, a hollow electrochemical cell includes two sets of electrodes and an opening for admitting an analyte to the cell. At least one of the two sets of electrodes can be in fluid communication with the opening. Further, a first set of electrodes can include a working electrode spaced from a counter or counter/reference electrode by less than 500 &#x3bc;m one embodiment the working and counter or counter/reference electrodes are not co-planer. In another embodiment the working and counter or counter/reference electrodes are of substantially corresponding area. In yet another embodiment the working and counter or counter/reference electrodes are spaced from 100 to 200 &#x3bc;m apart. The first set of electrodes and the second set of electrodes can be spaced apart by greater than about 500 &#x3bc;m. Other embodiments of a hollow electrochemical cell are also provided, as are several embodiments of a glucose sensor.

A method for determining the concentration of a reduced or oxidized form of a redox species is provided. In one exemplary embodiment, an electrochemical apparatus is provided in which the apparatus includes a hollow electrochemical cell for measuring a concentration of glucose in a blood sample, a current of the cell is measured, and a concentration of a redox mediator is determined, at least in part from, a measured current of the cell. The hollow electrochemical cell can include at least one non-metal working electrode, at least one counter electrode or counter/reference electrode, and a spacer interposed between the working electrode and the counter or counter/reference electrode. In one embodiment the working electrode and the counter or counter/reference electrode are not co-planer and are separated by a distance of from about 20 microns to about 200 microns. In another embodiment the working electrode and the counter or counter/reference electrode are not co-planer and the cell has an effective cell volume of less than 1.5 microliters.

A biosensor for use in determining a concentration of a component in an aqueous liquid sample is provided including: an electrochemical cell having a first electrically resistive substrate having a thin layer of electrically conductive material, a second electrically resistive substrate having a thin layer of electrically conductive material, the substrates being disposed with the electrically conductive materials facing each other and being separated by a sheet including an aperture, the wall of which aperture defines a cell wall and a sample introduction aperture whereby the aqueous liquid sample may be introduced into the cell; and a measuring circuit.

A reactor for preparing carbon nanotubes comprising a reaction chamber, at least one support means located within said reaction chamber capable of supporting a substrate, said substrate being capable of supporting carbon nanotube growth, at least one heating element located within said reaction chamber capable of providing localized heating to said substrate within said reaction chamber, and means for passing a gaseous carbonaceous material into said reaction chamber such that is passes over the contacts said substrate.

Apparatus for the production of carbon nanotubes

A method for determining the concentration of a reduced (or oxidised) form of a redox species in an electrochemical cell of the kind comprising a working electrode and a counter electrode spaced from the working electrode by a predetermined distance, said method comprising the steps of: (1) applying an electric potential difference between the electrodes; (2) selecting the potential of the working electrode such that the rate of electro-oxidation of the reduced form (or electro-reduction of the oxidised form) of the species is diffusion controlled, (3) selecting the spacing between the working electrode and the counter electrode so that reaction products from the counter electrode arrive at the working electrode; (4) determining current as a function of time after application of the potential and prior to achievement of a steady state; (5) estimating the magnitude of the steady state current, and (6) obtaining from the change in current with time and the magnitude of the steady state current, a value indicative of the diffusion coefficient and/or of the concentration of the reduced form (or the oxidised form) of the species. Also disclosed is an apparatus for determining the concentration of a redox species in an electrochemical cell comprising: an electrochemical cell having a working electrode and a counter (or counter/reference) electrode, means for applying and electric potential difference between said electrodes, means for measuring the change in current with time, and characterised in that the working electrode is spaced from the counter electrode by less than 500 &mgr;m.

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Mulgrave, Australia

Oddvar Johansen