Strip electrode with screen printing

Claim 2

A single use disposable electrode strip for attachment to signal readout circuitry of a sensor system to detect a current representative of a compound in a blood sample, the strip comprising: a) an elongated support having a substantially flat, planar surface, adapted for releasable attachment to said readout circuitry; b) a first conductor extending along said surface and comprising a conductive element for connection to said readout circuitry; c) an active electrode on said surface in contact with said first conductor, said active electrode comprising, in a single layer on said surface an admixture of an enzyme capable of catalyzing a reaction involving a substrate for said enzyme, a conductive material, and a mediator capable of transferring electrons transferred between said enzyme-catalyzed reaction and said first conductor to create a current representative of the activity of said enzyme and representative of said compound; d) a second conductor extending along said surface, comprising a conductive element for connection to said readout circuitry; and e) a reference electrode in contact with said second conductor, said first conductor and said active electrode spaced apart from said second conductor and said reference electrode and said active electrode being sized and positioned to present a combined effective area small enough to be completely coverable by a drop of blood contacting on the active electrode, whereby said blood completes an electrical circuit across said active electrode and said reference electrode, for amperometric detection of said activity of said enzyme.

Claim 3

The electrode strip of claim 1 further comprising, on said elongated support at an end thereof remote from said conductive elements, an area not covered by an electrode to allow for handling of said strip.

Claim 4

The electrode strip of claim 1, wherein said strip includes only one active electrode.

Claim 5

The electrode strip of claim 1 wherein said conductive elements for connection to said readout circuitry are positioned toward one end of said elongated flat flat support, and said electrodes are positioned remote from said end.

Claim 6

The electrode strip of claim 4 wherein said conductive elements are configured so as to allow releasable attachment with a socket on a read out meter.

Claim 7

The electrode strip of claim 5 wherein said conductive elements are configured so as to allow releasable attachment to a resilient mounting member disposed in said socket.

Claim 8

The electrode strip of claim 1 wherein said mediator is a ferrocene.

Claim 9

The electrode strip of either claims 1 or 7 wherein the compound is glucose and said enzyme is glucose oxidase or glucose dehydrogenase.

Claim 10

The electrode strip of any one of claims 1, 7 or 8 in which said mediator in said admixture is adsorbed on said conductive material in said admixture.

Claim 11

Apparatus for detecting a current representative of a compound in a blood sample, the apparatus comprising signal readout circuitry and an electrode strip comprising: a) an elongated support having a substantially flat, planar surface, adapted for releasable attachment to said signal-readout circuitry; b) a first conductor extending along said surface and comprising a conductive element for connection to said readout circuitry; c) an active electrode on said surface in contact with said first conductor, said active electrode comprising, in a single layer on said surface, an admixture of an enzyme capable of catalyzing a reaction involving a substrate for said enzyme, a conductive material, and a mediator capable of transferring electrons transferred between said enzyme-catalyzed reaction and said first conductor to create a current representative of the activity of said enzyme and representative of said compound; d) a second conductor extending along said surface, comprising a conductive element for connection to said readout circuitry; and e) a reference electrode in contact with said second conductive conductor, said first conductor and said active electrode spaced apart from said second conductor and said reference electrode, said electrodes being sized and positioned sufficiently close together to present a combined effective area small enough to be completely coverable by a drop of blood contacting on said active electrode, whereby said blood completes an electrical circuit across said active electrode and said reference electrode, for amperometric detection of said activity of said enzyme.

Claim 12

Apparatus for detecting a current representative of a compound in a blood sample, the apparatus comprising signal readout circuitry and an electrode strip comprising: a) an elongated support having a substantially flat, planar surface, adapted for releasable attachment to said signal-readout circuitry; b) a first conductor extending along said surface and comprising a conductive element for connection to said readout circuitry; c) an active electrode on said surface in contact with said first conductor, said active electrode comprising, in a single layer on said surface, an admixture of an enzyme capable of catalyzing a reaction involving a substrate for said enzyme, a conductive material, and a mediator capable of transferring electrons transferred between said enzyme-catalyzed reaction and said first conductor to create a current representative of the activity of said enzyme and representative of said compound; d) a second conductor extending along said surface, comprising a conductive element for connection to said readout circuitry; and e) a reference electrode in contact with said second conductive conductor, said first conductor and said active electrode spaced apart from said second conductor and said reference electrode, said electrodes being sized and positioned sufficiently close together to present a combined effective area small enough to be completely coverable by a drop of blood contacting on said active electrode, whereby said blood completes an electrical circuit across said active electrode and said reference electrode, for amperometric detection of said activity of said enzyme.

Claim 13

The apparatus of claim 10 wherein said conductive elements are positioned toward one end of an elongated flat support, and said electrodes are positioned remote from said end.

Claim 14

The apparatus of claim 10, wherein said strip includes only one active electrode.

Claim 15

The apparatus of claim 10 wherein said readout circuitry comprises a) an amplifier connected to amplify said electrical signal; b) a low pass filter connected to said amplifier output; c) a current-to-voltage converter, connected to said filter output; and d) a display connected to said converter for displaying a value representative of the voltage output of said converter.

Claim 16

The apparatus of claim 13 comprising circuitry to maintain a substantially constant bias voltage across said electrodes during said current measurement, in the absence of a separate voltage reference.

Claim 17

The apparatus of claim 10 wherein said mediator compound is a ferrocene.

Claim 18

The apparatus of claim either of claim 10 or 15 wherein the substrate is glucose and said enzyme is glucose oxidase or glucose dehydrogenase.