GEL FORMATION TO REDUCE HEMATOCRIT SENSITIVITY IN ELECTROCHEMICAL TEST
First Claim
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1. A biosensor for measuring a constituent concentration in blood, said biosensor comprising, on a support substrate:
- a sample reception region for receiving a blood sample;
at least one electrode; and
a reaction reagent system comprising, in a gel matrix;
an oxidation-reduction enzyme specific for the constituent; and
at least one electron mediator capable of being reversibly reduced and oxidized such that an electrochemical signal resulting from the reduction or oxidation is related to the constituent concentration in the blood sample,wherein said gel matrix is sufficient to prevent at least some of the red cells in the blood sample from contacting the electrode.
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Abstract
Devices for determining the concentration of a constituent in a physiological sample that comprise gel matrices to filter red blood cells are provided. Examples of such devices include a biosensor comprising, on a support substrate, a sample reception region for receiving a blood sample; at least one electrode; and a reaction reagent system that is located in a gel matrix. The gel matrix disclosed herein is sufficient to prevent at least some of the red cells in the blood sample from contacting the electrode, and thus reduce the hematocrit sensitivity in the measurement.
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Citations
34 Claims
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1. A biosensor for measuring a constituent concentration in blood, said biosensor comprising, on a support substrate:
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a sample reception region for receiving a blood sample; at least one electrode; and a reaction reagent system comprising, in a gel matrix; an oxidation-reduction enzyme specific for the constituent; and at least one electron mediator capable of being reversibly reduced and oxidized such that an electrochemical signal resulting from the reduction or oxidation is related to the constituent concentration in the blood sample, wherein said gel matrix is sufficient to prevent at least some of the red cells in the blood sample from contacting the electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of making a plurality of biosensors, said method comprising:
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forming a plurality of biosensor structures on a first insulating sheet, wherein each biosensor structure is formed by; (a) forming a first conductive pattern on said first insulating sheet, said first conductive pattern including at least four electrodes, said at least four electrodes including a working electrode, a counter electrode, a fill-detect anode, and a fill-detect cathode; (b) forming a second conductive pattern on said first insulating sheet, said second conductive pattern including a plurality of electrode contacts for said at least four electrodes, a plurality of conductive traces electrically connecting said at least four electrodes to said plurality of electrode contacts, and an auto-on conductor; (c) applying a first dielectric layer over portions of said working electrode and said counter electrode, so as to define an exposed working electrode portion and an exposed counter electrode portion; (d) applying a second dielectric layer to said first dielectric layer, said second dielectric layer defining a slot, said working electrode, said counter electrode, said fill-detect anode, and said fill-detect cathode being disposed in said slot; (e) forming a reagent system in said slot, said reagent system comprising, in a gel matrix; an oxidation-reduction enzyme specific for the constituent; and at least one electron mediator capable of being reversibly reduced and oxidized such that an electrochemical signal resulting from the reduction or oxidation is related to the constituent concentration in the blood sample, wherein said gel matrix is sufficient to prevent at least some of the red cells in the blood sample from contacting at least one electrode; (f) forming an adhesive layer on said second dielectric layer, said adhesive layer having a break extending from said slot; and (g) attaching a second insulating sheet to said adhesive layer, such that said second insulating sheet covers said slot but not said electrode contacts or said auto-on conductor; and (h) separating said plurality of biosensor structures into said plurality of biosensors, each having a proximal end and a distal end, with said slot extending to said proximal end, said proximal end being narrower than said distal end. - View Dependent Claims (26, 27, 28, 29)
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30. A method of making a plurality of biosensors, said method comprising:
forming a plurality of biosensor structures on one sheet, each of said biosensor structures including; (a) a spacer defining a sample chamber; (b) a plurality of electrodes formed on said sheet, including a working electrode, a counter electrode, a fill-detect anode, and a fill-detect cathode; (c) a plurality of electrical contacts, formed on said sheet and electrically connected to said plurality of electrodes; and (d) at least one auto-on electrical contact, formed on said sheet and electrically isolated from said plurality of electrodes; and
separating said biosensor structures into said plurality of biosensors,wherein said sample chamber includes a reaction reagent system comprising, in a gel matrix; an oxidation-reduction enzyme specific for the constituent; and at least one electron mediator capable of being reversibly reduced and oxidized such that an electrochemical signal resulting from the reduction or oxidation is related to the constituent concentration in the blood sample, wherein said gel matrix is sufficient to prevent at least some of the red cells in the blood sample from contacting the electrode. - View Dependent Claims (31, 32, 33, 34)
Specification