US 8,617,366 B2 · Disposable urea sensor and system for determining creatinine and urea nitrogen-to-creatinine ratio in a single device

Abstract

A disposable urea sensor has a laminated body having a fluid sample inlet end and an electrical contact end, a fluid sample inlet, a substantially flat sample chamber in communication between the fluid sample inlet and a vent opening, the sample chamber being adapted to collect a fluid sample through the fluid sample inlet, a working electrode and a reference electrode within the sample chamber, and a reagent matrix disposed on the working electrode wherein the reagent matrix contains urease.

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Drawings

Claims5

Dependent claims

A disposable urea sensor comprising:

a laminated body having a fluid sample inlet end and an electrical contact end, said laminated body includes a base layer, a reagent holding layer with cutouts defining a working electrode and a reference electrode, a channel forming layer and a cover;
a fluid sample inlet at said fluid sample inlet end;
a substantially flat sample chamber in communication between said fluid sample inlet and a vent opening wherein said sample chamber is adapted to collect a fluid sample through said fluid sample inlet, said substantially flat sample chamber defined by said base layer, said reagent holding layer, said channel forming layer and said cover;
a working electrode and a reference electrode within said sample chamber;
and
a dissolvable mixture of a reagent matrix disposed directly on said working electrode wherein said reagent matrix contains urease but absent any redox mediator and a dissolvable mixture of a reference matrix disposed directly on said reference electrode wherein said reference matrix contains a redox mediator.

3 more elements

Dependencies are inferred from the claim text.

Description11,961 words

Summary5,597 words

#1. Field of the Invention

#The present invention relates generally to electrochemical sensors that can be used for the quantification of a specific component or analyte in a liquid sample. Particularly, the present invention relates to a disposable electrochemical sensor for measuring urea (or BUN, Blood Urea Nitrogen) in biological fluids such as blood. More particularly, the present invention relates to a system for simultaneously determining creatinine and BUN-to-creatinine ratio in a single device. Still more particularly, the present invention relates to a device that can be employed to perform assays of urea, creatinine and blood urea nitrogen-to-creatinine ratio in a small volume liquid sample (around 1 μL).

#2. Description of the Prior Art

Brief description of the drawings15 figures

#FIG. 1 is a perspective view of one embodiment of the present invention showing the test strip.

#FIG. 2 is an exploded view of the embodiment in FIG. 1 showing the four component layers of the test strip.

#FIG. 3 is a perspective view of another embodiment of the present invention showing the combination of a BUN sensor strip and a creatinine sensor strip.

Detailed description5,944 words

#The preferred embodiment(s) of the present invention is illustrated in FIGS. 1-15. FIG. 1 shows a urea sensor 10 of the present invention. Sensor 10 has a laminated body 12, a fluid sampling end 14, an electrical contact end 16, and a vent opening 52. Sensor 10 may also include an optional inlet notch 54. Fluid sampling end 14 includes a sample chamber 17 between a sampling end inlet 18 and vent opening 52. Electrical contact end 16 has three discrete conductive contacts 16a, 16b and 16c.

#Referring now to FIG. 2, laminated body 12 is composed of a base layer 20, a reagent holding layer 30, a channel forming layer 40, and a cover 50. All layers of laminated body 12 are made of a dielectric material, preferably plastic. Examples of a preferred dielectric material are polyvinyl chloride, polycarbonate, polysulfone, nylon, polyurethane, cellulose nitrate, cellulose propionate, cellulose acetate, cellulose acetate butyrate, polyester, polyimide, polypropylene, polyethylene and polystyrene.

#Base layer 20 has a conductive layer 21 on which is delineated three conductive paths 22, 24 and 26. The conductive paths 22, 24 and 26 may be formed by scribing or scoring conductive layer 21, or by silk-screening conductive paths 22, 24 and 26 onto base layer 20. Scribing or scoring of conductive layer 21 may be done by mechanically scribing the conductive layer 21 sufficiently to create at least three independent conductive paths 22, 24 and 26. The preferred scribing or scoring method of the present invention is done by using a carbon dioxide laser, a YAG laser or an eximer laser. An additional scoring line 28 (enlarged and not to scale; for illustrative purposes only) may be made, but is not necessary to the functionality of sensor 10, along the outer edge of base layer 20 in order to avoid potential static problems which could give rise to a noisy signal. Conductive layer 21 may be made of any electrically conductive material such as, for example, gold, tin oxide/gold, palladium, other noble metals or their oxides, or carbon film compositions. The preferred electrically conductive material is gold or tin oxide/gold. A usable material for bottom layer 20 is a tin oxide/gold polyester film (Cat. No. FM-1) or a gold polyester film (Cat. No. FM-2) sold by Courtaulds Performance Films, Canoga Park, Calif.

Facts

Application

11/164,935Filed 12 Dec 2005

Published

US 2007/0131548 A114 Jun 2007

Granted

31 Dec 2013

Term ends

23 Apr 2029

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 1,228 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification4 codes

C12Q 1/005
Enzyme electrodes: involving specific analytes or enzymes
G01N 27/3271
Biochemical electrodes , e.g. electrical or mechanical details for in vitro measurements: amperometric enzyme electrodes for analytes in body…
C12Q
Measuring or testing processes involving enzymes, nucleic acids or microorganisms
G01N
Investigating or analysing materials by determining their chemical or physical properties

Timeline

12 Dec 2005Application filedUS 11/164,935
12 Dec 2005Assigned to Nova Biomedical Corporationassignment of assignor's interest
14 Jun 2007PublishedUS 2007/0131548 A1
31 Dec 2013GrantedUS 8,617,366 B2
11 Jul 2025Assigned to Glas Trust Company LLCsecurity interest
12 Oct 2026TodayWithin its term
23 Apr 2029Term endsEstimated, includes 1,228 days of adjustment

Disposable urea sensor and system for determining creatinine and urea nitrogen-to-creatinine ratio in a single device

Life of this patent

Disposable urea sensor and system for determining creatinine and urea nitrogen-to-creatinine ratio in a single device

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims5

Description11,961 words

Drawings

Classification4 codes

Life of this patent

Description11,961 words