Disposable urea sensor and system for determining creatinine and urea nitrogen-to-creatinine ratio in a single device
Inventors
Winarta, Handani • Pei, Jianhong • Lauro, Mary • Young, Chung Chang • Cai, Xiaohua
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-8617366-B2
Publication Date
2013-12-31
Expiration Date
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.
Core Innovation
The invention provides a disposable urea sensor comprising a laminated body with a fluid sample inlet end and an electrical contact end. The 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 substantially flat sample chamber is formed in communication between the fluid sample inlet and a vent opening, and the sample chamber is defined by the base layer, the reagent holding layer, the channel forming layer, and the cover.
Within the sample chamber, a working electrode and a reference electrode are provided, and each electrode carries a dissolvable mixture directly disposed on the electrode. The dissolvable mixture of a reagent matrix is disposed directly on the working electrode, and the reagent matrix contains urease but is absent any redox mediator. A dissolvable mixture of a reference matrix is disposed directly on the reference electrode, and the reference matrix contains a redox mediator.
In integrated embodiments, multiple electrode configurations and multi-channel strip layouts are described for point-of-care determination. These embodiments include additional electrodes such as blank/interference-compensating electrodes and creatinine/creatine enzyme electrodes, and the sensor is used to determine urea/creatinine and BUN-to-creatinine ratio using a small blood volume.
Claims Coverage
The independent claim describes one disposable urea sensor architecture with a laminated flat sample chamber and electrode-local dissolvable matrices that separate urease (without redox mediator) on the working electrode from a redox mediator on the reference electrode. Dependent claims refine the reagent matrix composition and optionally add a blank electrode with a separate buffer-containing reagent matrix; no additional independent claims are explicitly provided in the partial content.
Laminated body with flat sample chamber and vent opening
A laminated body having a fluid sample inlet end and an electrical contact end, including a base layer, a reagent holding layer with cutouts defining a working electrode and a reference electrode, a channel forming layer and a cover, and a fluid sample inlet leading to a substantially flat sample chamber in communication with a vent opening, wherein the sample chamber is defined by the base layer, the reagent holding layer, the channel forming layer and the cover.
Electrode-local dissolvable urease reagent matrix absent redox mediator on working electrode
A working electrode and a reference electrode within the sample chamber, with a dissolvable mixture of a reagent matrix disposed directly on the working electrode wherein the reagent matrix contains urease and is absent any redox mediator.
Electrode-local dissolvable reference matrix containing a redox mediator on reference electrode
A dissolvable mixture of a reference matrix disposed directly on the reference electrode wherein the reference matrix contains a redox mediator.
Reagent matrix including selected formulation materials
The reagent matrix further includes one or more materials selected from binder, buffer, surfactant, stabilizer, and bulking agent.
Cellulose binder in reagent matrix
The binder is a cellulose material.
Hydroxypropyl cellulose binder in reagent matrix
The cellulose material is hydroxypropyl cellulose.
Blank electrode with separate buffer-containing reagent matrix
The sensor further comprising a blank electrode and a second reagent matrix disposed on the blank electrode wherein the second reagent matrix includes a buffer.
Overall, claim coverage centers on a disposable laminated urea sensor with a substantially flat sample chamber and vent opening, where urease is carried in a dissolvable reagent matrix directly on the working electrode without any redox mediator, and the redox mediator is carried in a dissolvable reference matrix directly on the reference electrode. Dependent claims cover formulation options for the reagent matrix (including cellulose and hydroxypropyl cellulose binders) and an optional blank electrode with a separate buffer-containing matrix.
Stated Advantages
Provides point-of-care determination of urea and related ratios using a disposable laminated urea sensor.
Enables simultaneous or multi-channel assays using a small blood volume in described integrated embodiments.
Gives correlated BUN readings versus clinical chemistry systems, with reported CV values for different reference electrode configurations.
Documented Applications
Point-of-care determination of urea/creatinine and BUN-to-creatinine ratio using a disposable laminated sensor with integrated electrode configurations.
Point-of-care urea determination using the disposable electrochemical urea (BUN) sensor with a laminated flat sample chamber and electrode-local reagent matrices.
Interested in licensing this patent?