Small volume in vitro analyte sensor
First Claim
1. A sensor strip for determining the concentration of an analyte in a sample, the sensor strip comprising:
- (a) a first substrate having a proximal end and an opposite distal end, the distal end being configured and arranged for insertion into a sensor reader, the first substrate defining a first side edge and a second side edge of the sensor extending from the proximal end to the distal end of the first substrate;
(b) a second substrate positioned over the first substrate;
(c) at least one working electrode on the first substrate; and
(d) at least one counter electrode on one of the first substrate and the second substrate, with a portion of the counter electrode located 25-1000 micrometers from a portion of the at least one working electrode. (e) a spacer between the first and second substrates defining;
(i) a first aperture along the proximal end of the sensor, and (ii) a sample chamber extending from the first aperture to the second aperture, the sample chamber comprising a measurement zone having a volume of no more than 1 microliter, and the sample chamber defining a recess having al least a portion of the working electrode and a redox mediator situated in the recess.
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Accused Products
Abstract
A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.
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Citations
21 Claims
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1. A sensor strip for determining the concentration of an analyte in a sample, the sensor strip comprising:
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(a) a first substrate having a proximal end and an opposite distal end, the distal end being configured and arranged for insertion into a sensor reader, the first substrate defining a first side edge and a second side edge of the sensor extending from the proximal end to the distal end of the first substrate;
(b) a second substrate positioned over the first substrate;
(c) at least one working electrode on the first substrate; and
(d) at least one counter electrode on one of the first substrate and the second substrate, with a portion of the counter electrode located 25-1000 micrometers from a portion of the at least one working electrode. (e) a spacer between the first and second substrates defining;
(i) a first aperture along the proximal end of the sensor, and (ii) a sample chamber extending from the first aperture to the second aperture, the sample chamber comprising a measurement zone having a volume of no more than 1 microliter, and the sample chamber defining a recess having al least a portion of the working electrode and a redox mediator situated in the recess. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A sensor strip for determining the concentration of an analyte in a sample, the sensor strip comprising:
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(a) a first substrate having a proximal end and an opposite distal end, the distal end being configured and arranged for insertion into a sensor reader, the first substrate defining a first side edge and a second side edge of the sensor extending from the proximal end to the distal end of the first substrate;
(b) a second substrate positioned over the first substrate;
(c) at least one working electrode comprising gold on the first substrate; and
(d) at least one counter electrode comprising gold on the first substrate, with a portion of the counter electrode located 25-1000 micrometers from a portion of the at least one working electrode. (e) a spacer layer between the first and second substrates defining;
(i) a first aperture along the proximal end of the sensor, and (ii) a sample chamber extending from the first aperture to the second aperture, the sample chamber comprising a measurement zone having a volume of no more than 1 microliter, and the sample chamber defining a recess having al least a portion of the working electrode and a redox mediator situated in the recess. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification