US 8,298,389 B2 · In vitro analyte sensor, and methods

Abstract

In vitro electrochemical sensor that provide accurate and repeatable analysis of a sample of biological fluid are provided. In some embodiments, the sensors have a measurement zone that has a volume less than the volume of the sample chamber. The measurement zone could have a volume of no more than about 0.2 μL.

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Claims27

Dependent claims

A system for determining the concentration of an analyte in a sample, the system comprising:

a sensor comprising:
(a) a first substrate and a second substrate;
(b) a sample chamber present between the first substrate and the second substrate, the sample chamber having an inlet, a volume of no more than about 1 μL, and having therein:
(c) a working electrode on the first substrate;
(d) a counter electrode on the second substrate opposed to the working electrode, together the working electrode and the counter electrode having a distance therebetween and forming an electrode overlap, with the distance therebetween being no more than 10% of an axial length of the overlap;
(e) a pair of indicator electrodes, wherein one of the indicator electrodes in the pair is located on the first substrate and the other indicator electrode in the pair is located on the second substrate, wherein the pair of indicator electrodes is located downstream of the working and counter electrodes;
and
(f) a measurement zone having a volume about 75% or less than the volume of the sample chamber, the measurement zone defined by the electrode overlap,
wherein the sensor is configured to determine the concentration of the analyte in the sample that only partially fills the sample chamber,
wherein the sample chamber consists of the working electrode, the counter electrode, and the pair of indicator electrodes,
wherein the indicator electrodes are configured to confirm that the sample has stopped flowing in the sample chamber before the determining of the concentration of the analyte;
and
a meter programmed to monitor a change in an existing signal from the indicator electrodes to confirm that the sample has stopped flowing in the sample chamber before the determining of the concentration of the analyte.

10 more elements

A system for determining the concentration of an analyte in a sample, the system comprising:

a sensor comprising a sample chamber having a volume and a measurement zone within the sample chamber having a volume about 75% or less than the volume of the sample chamber,
wherein the sensor is configured to determine the concentration of the analyte in a sample that only partially fills the sample chamber,
wherein the sensor comprises a first substrate, a second substrate, a working electrode, a counter electrode, and a pair of indicator electrodes, wherein the working and counter electrodes face each other and have a distance therebetween, the distance between the working and counter electrodes is the thickness of the measurement zone, and wherein the pair of indicator electrodes face each other and are located downstream of the working and counter electrodes, wherein a first indicator electrode in said pair of indicator electrodes is located on the first substrate and a second indicator electrode in said pair of indicator electrodes is located on the second substrate,
wherein the thickness of the measurement zone is no more than 10% of the axial length of the measurement zone,
wherein the sample chamber consists of the working electrode, the counter electrode, and the indicator electrodes,
wherein the indicator electrodes are configured to confirm that the sample has stopped flowing in the sample chamber before the determining of the concentration of the analyte;
and
a meter programmed to monitor a change in an existing signal from the indicator electrodes to confirm that the sample has stopped flowing in the sample chamber before the determining of the concentration of the analyte.

5 more elements

A system for determining the concentration of an analyte in a sample, the system comprising:

a sensor comprising:
(a) a sample chamber having a volume of no more than 1 μL;
and
(b) a measurement zone within the sample chamber, the measurement zone having a volume about 75% or less than the volume of the sample chamber,
wherein the sensor is configured to determine the concentration of the analyte in the sample that only partially fills the sample chamber,
wherein the sensor comprises a first substrate, a second substrate, a working electrode, a counter electrode, and a pair of indicator electrodes, wherein the working and counter electrodes face each other and have a distance therebetween, the distance between the working and counter electrodes is the thickness of the measurement zone, and wherein the pair of indicator electrodes face each other and are located downstream of the working and counter electrodes, wherein a first indicator electrode in said pair of indicator electrodes is located on the first substrate and a second indicator electrode in said pair of indicator electrodes is located on the second substrate,
wherein the distance between the working electrode and the counter electrode is less than about 10% of an axial length of the measurement zone, and
wherein the sample chamber consists of the working electrode, the counter electrode, and the indicator electrodes,
wherein the indicator electrodes are configured to confirm that the sample has stopped flowing in the sample chamber before the determining of the concentration of the analyte;
and
a meter programmed to monitor a change in an existing signal from the indicator electrodes to confirm that the sample has stopped flowing in the sample chamber before the determining of the concentration of the analyte.

8 more elements

A system for determining the concentration of an analyte in a sample, the system comprising:

a sensor comprising:
(a) a first substrate, a second substrate, and a sample chamber having a volume;
(b) a measurement zone within the sample chamber, the measurement zone having an axial length less than the axial length of the sample chamber and a volume about 75% or less than the volume of the sample chamber;
and
(c) a working electrode and a counter electrode facing each other and having a distance therebetween, the electrodes being in the measurement zone;
wherein the distance between the working electrode and the counter electrode is less than 10% of the axial length of the measurement zone;
and
(d) a pair of indicator electrodes, wherein the pair of indicator electrodes face each other and are located downstream of the working and counter electrodes, wherein a first indicator electrode in said pair of indicator electrodes is located on the first substrate and a second indicator electrode in said pair of indicator electrodes is located on the second substrate,
wherein the sensor is configured to determine the concentration of the analyte in the sample that only partially fills the sample chamber,
wherein the sample chamber consists of the working electrode, the counter electrode, and the indicator electrodes,
wherein the indicator electrodes are configured to confirm that the sample has stopped flowing in the sample chamber before the determining of the concentration of the analyte;
and
a meter programmed to monitor a change in an existing signal from the indicator electrodes to confirm that the sample has stopped flowing in the sample chamber before the determining of the concentration of the analyte.

10 more elements

Dependencies are inferred from the claim text.

Description8,683 words

Summary1,343 words

#This invention relates to electrochemical sensors for the detection of analyte

#Electrochemical analytical sensors are commonly used to determine the presence and concentration of a biological analyte. Such sensors are used, for example, to monitor blood glucose levels in diabetic patients.

#Although many currently available sensor strip products require relatively large sample volumes, e.g., generally requiring 3 μL or more of blood or other biological fluid, there has been a trend for small volume sizes, such as 1 μL and less. For example, U.S. Pat. Nos. 6,143,164, 6,338,790 and 6,616,819 provide various configurations of small volume (i.e., less than 1 μL), disposable sensors. These patents suggest that sensors with sample chamber volumes of 0.5 μL, 0.25 μL, and even 0.1 μL can be made.

Brief description of the drawings10 figures

#Referring now to the drawings, wherein like reference numerals and letters indicate corresponding structure throughout the several views:

#FIG. 1 is a schematic, perspective view of an exemplary embodiment of an electrochemical sensor strip in accordance with the principles of the present invention;

#FIG. 2 is a top view of an embodiment of the sensor strip of FIG. 1;

Detailed description7,102 words

#The present invention is directed to small volume, in vitro analyte electrochemical sensors in which the measurement zone only partially fills the sample chamber volume. The sensors use a smaller biological fluid sample volume to obtain an accurate analyte reading than do previous sensor strips in which the entire sample chamber needs to be filled. The sensor strips of the present invention include a facing two-electrode system with an additional indicator electrode positioned downstream of the facing electrodes. With such a configuration, and when used with, e.g., coulometric techniques, the volume of the sample analyzed is the sample present between the two facing electrodes. This volume between the two facing electrodes is the measurement zone.

#Embodiments of the subject invention include sensors having a measurement zone that has a submicroliter volume, e.g., a volume of no more than about 0.2 μL, e.g., no more than about 0.15 μL, e.g., no more than about 0.1 μL. In some embodiments, the volume of the measurement zone may be as low as about 0.05 μL or as low as about 0.03 μL or less. The subject devices may be adapted for use with any biological fluid. For example, the biological fluid may be, but is not limited to, blood, serum, interstitial fluid, urine, tears, sweat, and the like. Likewise, the subject devices may be used to determine the concentration of a variety of analytes including but not limited to, glucose, lactate, and the like.

#Because only a portion of the sample volume present in the sample chamber is analyzed and the additional sample present within the sample chamber is not analyzed, the measurement accuracy is not dependent on the total amount of sample present in the sample chamber. The sensors of the present invention can determine the analyte concentration of a sample that does not fill the entire sample chamber; that is, it is not necessary that the sample chamber be completely filled with sample in order to obtain an accurate analyte concentration.

Facts

Application

11/225,659Filed 12 Sep 2005

Published

US 2007/0056858 A115 Mar 2007

Granted

30 Oct 2012

Term ends

18 Jun 2028

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 1,010 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.

Classification3 codes

G01N 27/327
Electrodes, e.g. test electrodes; Half-cells: biochemical electrodes , e.g. electrical or mechanical details for in vitro measurements
G01N 27/3272
Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood: test elements therefor, i.e. disposable laminated substrates…
G01N
Investigating or analysing materials by determining their chemical or physical properties

Timeline

12 Sep 2005Application filedUS 11/225,659
12 Sep 2005Assigned to Abbott Diabetes Care, Inc.assignment of assignor's interest
15 Mar 2007PublishedUS 2007/0056858 A1
30 Oct 2012GrantedUS 8,298,389 B2
12 Oct 2026TodayWithin its term
18 Jun 2028Term endsEstimated, includes 1,010 days of adjustment

In vitro analyte sensor, and methods

Life of this patent

In vitro analyte sensor, and methods

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims27

Description8,683 words

Classification3 codes

Life of this patent

Drawings

Description8,683 words