Disposable sensor for electrochemical detection of hemoglobin
First Claim
1. A sensor strip configured for hemoglobin measurements in a whole blood sample, comprising:
- a base layer having at least a first electrically conductive layer and a second electrically conductive layer disposed on a surface thereof;
a first amount of a reagent composition that includes at least an effective amount of a hemoglobin sensitive redox mediator and an effective amount of polymer binder in contact with said first electrically conductive layer to define a working electrode and a second amount of a reagent composition that includes an effective amount of polymer binder in contact with said second electrically conductive layer to define a reference electrode; and
a channel providing communication between said first amount and said second amount of reagent composition;
wherein said sensor strip returns a measurable electrical signal indicative of the hemoglobin content of a blood sample in response to an independent application of a variable voltage and a constant voltage across said working electrode and said reference electrode when said blood sample is in contact with said first and second amounts of reagent composition inside said channel.
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Accused Products
Abstract
A disposable biosensor for determining the content of hemoglobin and hematocrit in a sample of whole blood that includes a laminated strip with a first and second end, at least a reference, a working electrode and a blank electrode embedded in the laminated strip. The working electrode contains a reagent sensitive to hemoglobin or hemotocrit. The blank electrode is used to measure oxidizable species in the fluid sample and to correct the current signal of the working electrode. The construction of the biosensor allows accurate measurement of the impedance of a small fluid sample, which is used to further correct the current signal of the working electrode.
41 Citations
39 Claims
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1. A sensor strip configured for hemoglobin measurements in a whole blood sample, comprising:
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a base layer having at least a first electrically conductive layer and a second electrically conductive layer disposed on a surface thereof; a first amount of a reagent composition that includes at least an effective amount of a hemoglobin sensitive redox mediator and an effective amount of polymer binder in contact with said first electrically conductive layer to define a working electrode and a second amount of a reagent composition that includes an effective amount of polymer binder in contact with said second electrically conductive layer to define a reference electrode; and a channel providing communication between said first amount and said second amount of reagent composition; wherein said sensor strip returns a measurable electrical signal indicative of the hemoglobin content of a blood sample in response to an independent application of a variable voltage and a constant voltage across said working electrode and said reference electrode when said blood sample is in contact with said first and second amounts of reagent composition inside said channel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 37, 38, 39)
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17. A method for measuring the hemoglobin content of a sample of whole blood, comprising:
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introducing a hemoglobin sensitive redox mediator into said blood sample; applying an initial electrical potential to said blood sample; increasing said electrical potential in discrete steps until reaching an end electrical potential; and measuring an electrical parameter of said whole blood after application of each electrical potential. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A method for measuring the hemoglobin content of a sample of whole blood comprising:
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introducing a hemoglobin sensitive redox mediator into said sample of whole blood; obtaining an electrical current value for said sample of blood after said introducing step; obtaining an impedance value for said blood sample after said introducing step; multiplying said electrical current value with a first factor; multiplying said impedance value with a second factor; and adding the result of said first multiplication step to the result of said second multiplication;
wherein said first factor and said second factor add up to one. - View Dependent Claims (25, 26, 27)
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28. A sensor strip configured for hemoglobin measurements in a whole blood sample, comprising:
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a base layer having at least a first electrically conductive layer and a second electrically conductive layer disposed on a surface thereof; a first amount of a reagent composition that includes at least an effective amount of a hemoglobin sensitive redox mediator and an effective amount of polymer binder in contact with said first electrically conductive layer to define a working electrode and a second amount of a reagent composition that includes an effective amount of polymer binder in contact with said second electrically conductive layer to define a reference electrode; and a channel providing communication between said first amount and said second amount of reagent composition; wherein said sensor strip returns a measurable electrical signal indicative of the hemoglobin content of a blood sample having a volume in the range 1.6 micro liter to 10 micro liter in response to an application of voltage across said working electrode and said reference electrode when said blood sample is in contact with said first and second amounts of reagent composition inside said channel.
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29. A method for measuring hematocrit content in a sample of whole blood comprising:
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measuring the hemoglobin content of said whole blood sample using a sensor strip that includes a base layer having at least a first electrically conductive layer and a second electrically conductive layer disposed on a surface thereof; a first amount of a reagent composition that includes at least an effective amount of a hemoglobin sensitive redox mediator in contact with said first electrically conductive layer to define a working electrode and a second amount of a reagent composition in contact with said second electrically conductive layer to define a reference electrode; and a channel providing communication between said first amount and said second amount of reagent composition; wherein said sensor strip returns a measurable electrical signal indicative of the hemoglobin content of a blood sample in response to an independent application of a variable voltage and a constant voltage across said working electrode and said reference electrode when said blood sample is in contact with said first and second amount of reagent composition inside said channel; determining the hematocrit content based on the measured hemoglobin content using a linear relationship of the form
Hct=aHb+bwherein Hot represents hematocrit content, Hb is the hemoglobin content and a and b are constants. - View Dependent Claims (30)
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31. A sensor strip configured for hemoglobin measurements in a whole blood sample, comprising:
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a base layer; at least a first electrically conductive layer, a second electrically conductive layer, and a third electrically conductive layer on said base layer; a first amount of a first reagent composition that includes at least an effective amount of a hemoglobin sensitive redox mediator in contact with said first electrically conductive layer to define a working electrode and a second amount of a second reagent composition in contact with said second electrically conductive layer to define a reference electrode; a third reagent composition in contact with said third conductive layer to define a blank electrode, said third reagent composition including a hemoglobin insensitive redox mediator; and a channel providing communication between said first amount and said second amount of said reagent composition; wherein said sensor strip returns a measurable electrical signal indicative of the hemoglobin content of a blood sample in response to an application of a voltage across said working electrode and said reference electrode when said blood sample is in contact with said first and second amount of said reagent composition inside said channel;
wherein said measurable electrical signal is not influenced by the presence of an amount less than a maximum amount of an interfering oxidizable species. - View Dependent Claims (32)
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33. A method of measuring hemoglobin in whole blood using a sensor strip that includes a base layer;
- at least a first electrically conductive layer, a second electrically conductive layer, and a third electrically conductive layer on said base layer;
a first amount of a reagent composition that includes at least an effective amount of a hemoglobin sensitive redox mediator in contact with said first electrically conductive layer to define a working electrode and a second amount of a second reagent composition in contact with said second electrically conductive layer to define a reference electrode;
a third reagent composition in contact with said third conductive layer to define a blank electrode, said third reagent composition including a hemoglobin insensitive redox mediator; and
a channel providing communication between said first amount and said second amount of said reagent composition;
wherein said sensor strip returns a measurable electrical signal indicative of the hemoglobin content of a blood sample in response to an application of a voltage to said working electrode and said reference electrode when said blood sample is in contact with said first and second amount of said reagent composition inside said channel, the method comprising;applying a first voltage across said blank electrode and said reference electrode for a first period of time; applying a second voltage across said working electrode and said reference electrode for a second period of time; and after an open circuit delay for a third period of time, applying linear scan voltammetry across said working and reference electrodes in voltage increments from an initial voltage value to a final voltage value at a predetermined rate to determine electrical current values at the voltage increments; and determining the hemoglobin content from the peak current value obtained from application of said linear scan voltammetry. - View Dependent Claims (34)
- at least a first electrically conductive layer, a second electrically conductive layer, and a third electrically conductive layer on said base layer;
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35. A method of measuring hemoglobin in whole blood using a sensor strip that includes a base layer;
- at least a first electrically conductive layer, a second electrically conductive layer, and a third electrically conductive layer on said base layer;
a first amount of a reagent composition that includes at least an effective amount of a hemoglobin sensitive redox mediator in contact with said first electrically conductive layer to define a working electrode and a second amount of a second reagent composition in contact with said second electrically conductive layer to define a reference electrode;
a third reagent composition in contact with said third conductive layer to define a blank electrode, said third reagent composition including a hemoglobin insensitive redox mediator; and
a channel providing communication between said first amount and said second amount of said reagent composition;
wherein said sensor strip returns a measurable electrical signal indicative of the hemoglobin content of a blood sample in response to an application of a voltage across said working electrode and said reference electrode when said blood sample is in contact with said first and second amount of said reagent composition inside said channel, the method comprising;applying a first voltage across said blank electrode and said reference electrode for a first period of time; applying a second voltage across said working electrode and said reference electrode for a second period of time; and after an open circuit delay for a third period of time, applying a constant voltage while measuring the rise in current over time between said working and blank electrodes to determine the hemoglobin content. - View Dependent Claims (36)
- at least a first electrically conductive layer, a second electrically conductive layer, and a third electrically conductive layer on said base layer;
Specification