U.S. patent application number 09/729296 was filed with the patent office on 2002-08-01 for biosensor.
Invention is credited to Bhullar, Raghbir S., Hill, Brian S., Wilsey, Christopher D..
Application Number | 20020100684 09/729296 |
Document ID | / |
Family ID | 24930400 |
Filed Date | 2002-08-01 |
United States Patent
Application |
20020100684 |
Kind Code |
A1 |
Bhullar, Raghbir S. ; et
al. |
August 1, 2002 |
BIOSENSOR
Abstract
A biosensor is provided that includes first and second plate
elements, wherein each plate elements has first and second ends and
first and second lateral borders. In addition, the biosensor
includes a spacer positioned to lie between the first and second
plate elements so that at least a portion of the first and second
plate elements cooperate with one another to form opposite walls of
a capillary space. Further, the first ends and at least a portion
of the lateral borders define a fluid sample-receiving portion in
communication with the capillary space. Electrodes are positioned
in the capillary space of the biosensor.
Inventors: |
Bhullar, Raghbir S.;
(Indianapolis, IN) ; Wilsey, Christopher D.;
(Carmel, IN) ; Hill, Brian S.; (Avon, IN) |
Correspondence
Address: |
Jill Lynn Woodburn
The Law Office of Jill L. Woodburn, L.L.C.
6633 Old Stonehouse Dr.
Newburgh
IN
47630
US
|
Family ID: |
24930400 |
Appl. No.: |
09/729296 |
Filed: |
December 4, 2000 |
Current U.S.
Class: |
204/403.01 |
Current CPC
Class: |
G01N 27/3272
20130101 |
Class at
Publication: |
204/403.01 |
International
Class: |
G01N 027/327 |
Claims
What is claimed is:
1. A biosensor comprising: first and second plate elements, said
plate elements having first and second ends and first and second
lateral borders, a spacer positioned to lie between the first and
second plate elements so that at least a portion of the first and
second plate elements cooperate with one another to form opposite
walls of a capillary space and the first ends and at least a
portion of the opposite lateral borders define a fluid sample
receiving portion in communication with the capillary space, and
electrodes positioned in the capillary space.
2. The biosensor of claim 1, wherein the lateral borders are
straight.
3. The biosensor of claim 2, wherein the lateral borders are
parallel relative to one another.
4. The biosensor of claim 2, wherein the lateral borders converge
toward the first ends.
5. The biosensor of claim 1, wherein the lateral borders are
curved.
6. The biosensor of claim 1, wherein the spacer is an adhesive.
7. The biosensor of claim 1, where the ends of the first and second
plate elements are off-set from one another.
8. The biosensor of claim 7, wherein the ends of the first and
second plate elements are parallel relative to one another.
9. A biosensor comprising: first and second plate elements, said
plate elements having tabs with ends and first and second lateral
borders, electrodes positioned on the tab of said first plate
element, and a spacer positioned to lie between the plate elements
so that the tabs form opposite walls of a capillary space extending
between lateral borders and ends, wherein the ends and lateral
borders cooperate to define a fluid sample receiving portion in
communication with the capillary space.
10. The biosensor of claim 9, wherein the tabs are rectangular in
shape.
11. The biosensor of claim 10, wherein the ends of the first and
second plate elements are off-set relative to one another.
12. The biosensor of claim 11, wherein the lateral borders are the
same length as the ends.
13. The biosensor of claim 9, wherein the tabs are triangular in
shape.
14. The biosensor of claim 9, wherein the tabs are curved.
15. A biosensor comprising: first and second plate elements, said
plate elements including body portions with edges having a first
dimension and opposite ends and tabs extending from one of the
opposite ends, the tabs including lateral borders having a second
dimension, which is less than the first dimension, electrodes
positioned between the tabs, and a spacer positioned to lie between
the edges of the body portions so that the tabs form opposite walls
of a capillary space, wherein the tabs cooperate to define a fluid
sample receiving portion in communication with the capillary
space.
16. The biosensor of claim 15, wherein the lateral borders are
straight.
17. The biosensor of claim 16, wherein the tabs are rectangular in
shape.
18. The biosensor of claim 15, wherein the tabs are triangular in
shape.
19. The biosensor of claim 16, wherein the tabs include ends and
the ends of the tab have a third dimension that is equal to the
second dimension.
20. The biosensor of claim 15, wherein the lateral borders are
curved.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a biosensor and
particularly to an electrochemical biosensor.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] Electrochemical biosensors are known. They have been used to
determine the concentration of various analytes from biological
samples, particularly from blood. Biosensors are described in U.S.
Pat. Nos. 5,413,690; 5,762,770; 5,798,031; and 5,997,817, the
disclosure of each of which are expressly incorporated herein by
reference.
[0003] According to the present invention a biosensor is provided.
The biosensor comprises first and second plate elements, said plate
elements having first and second ends and first and second lateral
borders, a spacer positioned to lie between the first and second
plate elements so that at least a portion of the first and second
plate elements cooperate with one another to form opposite walls of
a capillary space and the first ends and at least a portion of the
lateral borders define a fluid sample receiving portion in
communication with the capillary space, and electrodes positioned
in the capillary space.
[0004] In addition, a biosensor is provided that comprises first
and second plate elements, said plate elements having tabs with
ends and first and second lateral borders, electrodes positioned on
the tab of said first plate element, and a spacer positioned to lie
between the plate elements so that the tabs form opposite walls of
a capillary space extending between lateral borders and ends,
wherein the ends and lateral borders cooperate to define a fluid
sample receiving portion in communication with the capillary
space.
[0005] Additional features of the invention will become apparent to
those skilled in the art upon consideration of the following
detailed description of the preferred embodiment exemplifying the
best mode of carrying out the invention
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The detailed description particularly refers to the
accompanying figures in which:
[0007] FIG. 1 is an exploded perspective view of a biosensor in
accordance with the present invention;
[0008] FIG. 2 is an assembled sectional view taken along lines 2-2
of FIG. 1;
[0009] FIG. 3 is an enlarged top view, with portions broken away,
of the biosensor of FIG. 1;
[0010] FIG. 4 is a top view of a biosensor in accordance with
another embodiment of the invention;
[0011] FIG. 5 is a top view of a biosensor in accordance with
another embodiment of the invention;
[0012] FIG. 6 is a top view of a biosensor in accordance with
another embodiment of the invention;
[0013] FIG. 7 is a top view of a biosensor in accordance with
another embodiment of the invention;
[0014] FIG. 8 is a top view of a biosensor in accordance with
another embodiment of the invention;
[0015] FIG. 9 is a top view of a biosensor in accordance with
another embodiment of the invention;
[0016] FIG. 10 is a top view of a biosensor in accordance with
another embodiment of the invention;
[0017] FIG. 11 is a top view of a biosensor in accordance with
another embodiment of the invention;
[0018] FIG. 12 is a top view of a biosensor in accordance with
another embodiment of the invention; and
[0019] FIG. 13 is a top view of a biosensor in accordance with
another embodiment of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0020] A biosensor 10 in accordance with the present invention is
shown in FIG. 1, as it would appear to a user just prior to use. As
shown in FIG. 2, biosensor 10 compensates for small sample volumes
by providing a cantilever based capillary design. Biosensor 10 is
an economical disposable sensor with an integrated design, which
can handle as low as about 500 nL sample volume.
[0021] FIGS. 1-11 illustrate an aspect of the invention in the form
of biosensor 10 having a top plate element 12 and a bottom plate
element 14, electrically conductive tracks 26, 28 and a reagent 80
situated between plate elements 12, 14, and a spacer 16. Spacer 16
separates top and bottom elements 12, 14, a portion of which
cooperate with one another to define a cantilevered capillary
channel 18. Biosensor 10 is preferably rectangular in shape. It is
appreciated, however, that biosensor 10 can assume any number of
shapes and can include more than one cantilevered capillary channel
18 in accordance with this disclosure. Biosensor 10 is preferably
produced from rolls of material, however, it is understood that
biosensor 10 can be constructed from individual sheets in
accordance with this disclosure. Thus, when biosensor 10 is to
produced from rolls of material, the selection of materials for the
construction of biosensor 10 necessitates the use of materials that
are sufficiently flexible for roll processing, but which are still
rigid enough to give a useful stiffness to finished biosensor 10.
Various aspects of the invention are presented in FIGS. 1-11, which
are not drawn to scale and wherein like components in the several
views are numbered alike.
[0022] Bottom plate element 14 of biosensor 10 includes a body
portion 20, a tab 22, and a connection portion 23. The body portion
20, tab 22, and connection portion 23 each includes a first surface
24 that supports conductive tracks 26, 28 and an opposite second
surface 30. See FIGS. 1 and 2. In addition, body portion 20 has
opposite ends 32, 34 and edges 36, 38 extending between ends 32,
34. First end 32 from which tab 22 extends has a pre-determined
width, which can vary in accordance with this disclosure.
Connection portion 23 extends from opposite end 34 of body portion
20.
[0023] Tab 22, includes lateral borders 42, 44 and an end 46.
Lateral borders 42, 44 have a predetermined width that is less than
the width of end 32 of body portion 20. In addition, tab 22 is
formed to include a recess 48. Recess 48 is formed to have three
sides and extend from end 32 and about electrodes 26, 28. A
detailed description of recess 48 is found in U.S. patent
application Ser. No. not yet available, entitled "BIOSENSOR", which
was filed in the U.S. Patent and Trademark Office on Oct. 6, 2000,
to Bhullar et al., the disclosure of which is expressly
incorporated herein by reference. It is appreciated, that biosensor
can be formed without recess 48 in accordance with this disclosure.
Further, bottom element 14 may be constructed from a wide variety
of insulative materials. Non-limiting examples of insulative
materials that provide desirable electrical and structural
properties include glass, ceramic, vinyl polymers, polyimides,
polyesters, and styrenics. Preferably, bottom plate element 14 is a
flexible polymer, such as a polyester or polyimide. A non-limiting
example of a suitable material is 5 mil thick KALADEX.RTM.
commercially available from E.I. DuPont de Nemours, Wilmington,
Del.
[0024] As shown in FIGS. 1 and 3, electrically conductive tracks
26, 28 are created or isolated on first surface 24 of plate element
14. Tracks 26, 28 represent the electrodes set of biosensor 10. As
used herein, the phrase "electrode set" is a set of at least two
electrodes, for example 2 to 200, or 3 to 20, electrodes. These
electrode sets may, for example, include a working electrode and an
auxiliary electrode. Tracks 26, 28 cooperate to form an
interdigitated electrode array 50 positioned on tab 22 and leads 52
that extend from array 50 across body portion 20 to end 34. Track
26 may be a working electrode and track 28 may be an auxiliary
electrode.
[0025] Tracks 26, 28 are constructed from electrically-conductive
materials. Non-limiting examples of electrically-conductive
materials include aluminum, carbon (such as graphite), cobalt,
copper, gallium, gold, indium, iridium, iron, lead, magnesium,
mercury (as an amalgam), nickel, niobium, osmium, palladium,
platinum, rhenium, rhodium, selenium, silicon (such as highly doped
polycrystalline silicon), silver, tantalum, tin, titanium,
tungsten, uranium, vanadium, zinc, zirconium, mixtures thereof, and
alloys, oxides, or metallic compounds of these elements.
Preferably, tracks include gold, platinum, palladium, iridium, or
alloys of these metals, since such noble metals and their alloys
are unreactive in biological systems. Most preferably, track 26 is
a working electrode made of gold, and track 28 is an auxiliary
electrode that is also made of gold and is substantially the same
size as the working electrode.
[0026] Tracks 26, 28 are preferably isolated from the rest of the
electrically conductive surface by laser ablation. Techniques for
forming electrodes on a surface using laser ablation are known.
See, for example, U.S. patent application No. 09/411,940, filed
Oct. 4, 1999, and entitled "LASER DEFINED FEATURES FOR PATTERNED
LAMINATES AND ELECTRODE", the disclosure of which is expressly
incorporated herein by reference. Tracks 26, 28 are preferably
created by removing the electrically conductive material from an
area extending around the electrodes. Therefore, tracks 26, 28 are
isolated from the rest of the electrically-conductive material on
bottom element 14 by a gap having a width of about 25 .mu.m to
about 500 .mu.m, preferably the gap has a width of about 100 .mu.m
to about 200 .mu.m. Alternatively, it is appreciated that tracks
26, 28 may be created by laser ablation alone on bottom element 14.
Further, tracks 26, 28 may be laminated, screen-printed, or formed
by photolithography in accordance with this disclosure.
[0027] Multi-electrode arrangements are also possible in accordance
with this disclosure. For example, it is contemplated that a
biosensor may be formed that that includes an additional
electrically conductive track (not shown). In a three-electrode
arrangement, the first track is a working electrode, the second is
a counter electrode, and the third electrode is a reference
electrode. It is also appreciated that an alternative
three-electrode arrangement is possible where tracks are working
electrodes and a third electrode is provided as an auxiliary or
reference electrode in accordance with this disclosure. It is
appreciated that the number of tracks, as well as the spacing
between tracks in array 50 may vary in accordance with this
disclosure and that a number of arrays may be formed as will be
appreciated by one of skill in the art.
[0028] Reagent 80 provides electrochemical probes for specific
analytes and is positioned in opening 18 such that reagent 80
covers interdigited electrode array 50. Reagent 80 is placed as a
film of generally uniform thickness over first surface 24 of tab 22
and across array 50. Reagent 80 will then present a hydrophilic
surface to the interior of capillary opening 18.
[0029] The choice of specific reagent 80 depends on the specific
analyte or analytes to be measured, and are well known to those of
ordinary skill in the art. An example of a reagent that may be used
in biosensor 10 of the present invention is a reagent for measuring
glucose from a whole blood sample. A non-limiting example of a
reagent for measurement of glucose in a human blood sample contains
62.2 mg polyethylene oxide (mean molecular weight of 100-900
kilodaltons), 3.3 mg NATROSOL 250M, 41.5 mg AVICEL RC-591 F, 89.4
mg monobasic potassium phosphate, 157.9 mg dibasic potassium
phosphate, 437.3 mg potassium ferricyanide, 46.0 mg sodium
succinate, 148.0 mg trehalose, 2.6 mg TRITON X-100 surfactant, and
2,000 to 9,000 units of enzyme activity per gram of reagent. The
enzyme is prepared as an enzyme solution from 12.5 mg coenzyme PQQ
and 1.21 million units of the apoenzyme of quinoprotein glucose
dehydrogenase. This reagent is further described in U.S. Pat. No.
5,997,817, the disclosure of which is incorporated herein by
reference.
[0030] When hematocrit is to be determined, the reagent includes
oxidized and reduced forms of a reversible electroactive compound
(potassium hexacyanoferrate (III) ("ferricyanide") and potassium
hexacyanoferrate (II) ("ferrocyanide"), respectively), an
electrolyte (potassium phosphate buffer), and a microcrystalline
material (Avicel RC-591F--a blend of 88% microcrystalline cellulose
and 12% sodium carboxymethyl-cellulose, available from FMC Corp.).
Concentrations of the components within the reagent before drying
are as follows: 400 millimolar (mM) ferricyanide, 55 mM
ferrocyanide, 400 mM potassium phosphate, and 2.0% (weight:volume)
Avicel. A further description of the reagent for a hematocrit assay
is found in U.S. Pat. No. 5,385,846, the disclosure of which is
incorporated herein by reference.
[0031] Non-limiting examples of enzymes and mediators that may be
used in measuring particular analytes in sensor 10 of the present
invention are listed below in Table 1.
1TABLE 1 Mediator Additional Analyte Enzymes (Oxidized Form)
Mediator Glucose Glucose Ferricyanide Dehydrogenase and Diaphorase
Glucose Glucose- Ferricyanide Dehydrogenase (Quinoprotein)
Cholesterol Cholesterol Ferricyanide 2,6-Dimethyl-1,4- Esterase and
Benzoquinone Cholesterol 2,5-Dichloro-1,4- Oxidase Benzoquinone or
Phenazine Ethosulfate HDL Cholesterol Ferricyanide
2,6-Dimethyl-1,4- Cholesterol Esterase and Benzoquinone Cholesterol
2,5-Dichloro-1,4- Oxidase Benzoquinone or Phenazine Ethosulfate
Triglycerides Lipoprotein Ferricyanide or Phenazine Lipase,
Glycerol Phenazine Methosulfate Kinase, and Ethosulfate Glycerol-3-
Phosphate Oxidase Lactate Lactate Oxidase Ferricyanide
2,6-Dichloro-1,4- Benzoquinone Lactate Lactate Ferricyanide
Dehydrogenase Phenazine and Diaphorase Ethosulfate, or Phenazine
Methosulfate Lactate Diaphorase Ferricyanide Phenazine
Dehydrogenase Ethosulfate, or Phenazine Methosulfate Pyruvate
Pyruvate Oxidase Ferricyanide Alcohol Alcohol Oxidase
Phenylenediamine Bilirubin Bilirubin Oxidase 1-Methoxy- Phenazine
Methosulfate Uric Acid Uricase Ferricyanide
[0032] In some of the examples shown in Table 1, at least one
additional enzyme is used as a reaction catalyst. Also, some of the
examples shown in Table 1 may utilize an additional mediator, which
facilitates electron transfer to the oxidized form of the mediator.
The additional mediator may be provided to the reagent in lesser
amount than the oxidized form of the mediator. While the above
assays are described, it is contemplated that current, charge,
impedance, conductance, potential, or other electrochemically
indicated property of the sample may be accurately correlated to
the concentration of the analyte in the sample with biosensor 10 in
accordance with this disclosure.
[0033] Referring again to FIG. 1, spacer 16 of biosensor 10 is
positioned to lie between top and bottom plate elements 12, 14.
Moreover, spacer 16 cooperates with top and bottom plate elements
12, 14 to expose array 50 to a liquid sample being applied to
biosensor 10 in capillary channel as shown by arrow 40 in FIG. 2.
Spacer 16 is a double-coated adhesive tape that is coupled to
bottom plate element 14 and tracks 16, 18. A non-limiting example
of such an adhesive is 3M High Performance Double Coated Tape 9500
PC, commercially available from Minnesota Mining and Manufacturing
Company, St. Paul, Minn. It is appreciated that spacer 16 may be
constructed of a variety of materials and may be coupled to top and
bottom plate elements 12, 14 using a wide variety of commercially
available adhesives. Additionally, when surface 24 of element 14 is
exposed and not covered by electrical conductor, spacer 16 may be
coupled to plate element 14 by welding (heat or ultrasonic) in
accordance with this disclosure.
[0034] Top plate element 12 of biosensor 10 includes a first
surface 58 facing spacer 16 and an opposite second surface 60. See
FIG. 2. Top plate element 12 of biosensor 10 includes a body
portion 54 that overlaps tracks 26, 28 and a tab 56 extending from
body portion 54 across array 50. In addition, body portion 54 has
opposite ends 62, 64 and edges 66, 68 extending between ends 62,
64. First end 62 from which tab 56 extends has a predetermined
width. This width of end 62 is generally equal to the width of end
32, although it is appreciated that this width can vary in
accordance with this disclosure.
[0035] Tab 56 of top plate element 12, includes lateral borders 72,
74 and an end 76. Lateral borders 72, 74 have a pre-determined
width that is less than the width of end 62 of body portion 54.
Upon assembly, end 64 of body portion 54 is positioned in general
alignment with end 34 of body portion 20. It is appreciated that
extent to which tracks 26, 28 are exposed for electrical connection
with a meter (not shown), which measures some electrical property
of a liquid sample after the sample is applied to biosensor 10. Top
plate element 12 may be constructed from a wide variety of
insulative materials. Non-limiting examples of insulative materials
that provide desirable properties include glass, ceramics, vinyl
polymers, polyimides, polyesters, and styrenics. Preferably, top
plate element 12 is a flexible polymer, such as a polyester or
polyimide. A non-limiting example of a suitable material is 7 mil
thick MELINEX.RTM. 329 commercially available from E.I. DuPont de
Nemours, Wilmington, Del.
[0036] A plurality of biosensors 10 are typically packaged in a
vial, usually with a stopper formed to seal the vial. It is
appreciated, however, that biosensors 10 may be packaged
individually, or biosensors can be folded upon one another, rolled
in a coil, stacked in cassette magazine, or packed in a blister
packaging.
[0037] Below is a non-limiting example of the use of biosensor 10
in conjunction with the following:
[0038] 1. a power source in electrical connection with the
electrodes and capable of supplying an electrical potential
difference between the electrodes sufficient to cause
diffusion-limited electro-oxidation of the reduced form of the
mediator at the surface of the working electrode; and
[0039] 2. a meter in electrical connection with the electrodes and
capable of measuring the diffusion-limited current produced by
oxidation of the reduced form of the mediator with the above-stated
electrical potential difference is applied.
[0040] The meter will normally be adapted to apply an algorithm to
the current measurement, whereby an analyte concentration is
provided and visually displayed. Improvements in such power source,
meter, and biosensor system are the subject of commonly assigned
U.S. Pat. No. 4,963,814, issued Oct. 16, 1990; U.S. Pat. No.
4,999,632, issued Mar. 12, 1991; U.S. Pat. No. 4,999,582, issued
Mar. 12, 1991; U.S. Pat. No. 5,243,516, issued Sep. 7, 1993; U.S.
Pat. No. 5,352,351, issued Oct. 4, 1994; U.S. Pat. No. 5,366,609,
issued Nov. 22, 1994; White et al., U.S. Pat. No. 5,405,511, issued
Apr. 11, 1995; and White et al., U.S. Pat. No. 5,438,271, issued
Aug. 1, 1995, the disclosures of which are hereby expressly
incorporated by reference.
[0041] Many fluid samples may be analyzed. For example, human body
fluids such as whole blood, plasma, sera, lymph, bile, urine,
semen, cerebrospinal fluid, spinal fluid, lacrimal fluid and stool
specimens as well as other biological fluids readily apparent to
one skilled in the art may be measured. Fluid preparations of
tissues can also be assayed, along with foods, fermentation
products and environmental substances, which potentially contain
environmental contaminants. Preferably, blood is assayed with this
invention.
[0042] In use, the user places a liquid sample against tabs 22, 56
of biosensor 10. The liquid sample will be drawn into capillary
channel as shown by arrow 40 in FIG. 2. When reagent 80 is the
reagent for measuring glucose as discussed above, sample containing
the analyte dissolves reagent 80 in capillary channel 18 to oxidize
the analyte and reduce the oxidized form of the mediator. The
reaction between the analyte and reagent 80 is permitted to go to
completion. (Completion is defined as sufficient reaction involving
analyte, enzyme, and mediator (oxidized form) to correlate analyte
concentration to diffusion-limited current generated by oxidation
of the reduced form of the mediator at the surface of the working
electrode.)
[0043] After reaction is complete, a power source (e.g., a battery)
applies a potential difference between electrodes. When the
potential difference is applied, the amount of oxidized form of the
mediator at the auxiliary electrode and the potential difference
must be sufficient to cause diffusion-limited electro-oxidation of
the reduced form of the mediator at the surface of the working
electrode. A current measuring meter (not shown) measures the
diffusion-limited current generated by the oxidation of the reduced
form of the mediator at the surface of the working electrode. The
measured current may be accurately correlated to the concentration
of the analyte in sample when the following requirements are
satisfied:
[0044] 1. The rate of oxidation of the reduced form of the mediator
is governed by the rate of diffusion of the reduced form of the
mediator to the surface of the working electrode.
[0045] 2. The current produced is limited by the oxidation of
reduced form of the mediator at the surface of the working
electrode.
[0046] To manufacture biosensor 10 a roll of metallized film is fed
through guide rolls into an ablation/washing and drying station. A
laser system capable of ablating bottom element material is known
to those of ordinary skill in the art. Non-limiting examples of
which include excimer lasers, with the pattern of ablation
controlled by mirrors, lenses, and masks. A non-limiting example of
such a system is the LPX-300 or LPX-200 both commercially available
from LPKF Laser Electronic GmbH, of Garbsen, Germany.
[0047] In the laser ablator, the metallic layer of the metallized
film is ablated in predetermined patterns, to form a ribbon of
isolated electrode sets. The metallized film is further ablated,
after the isolated electrode sets are formed, to create recesses 48
positioned adjacent to each electrochemical area. The ribbon is
then passed through more guide rolls, with a tension loop and
through an optional optical or electrical inspection system. This
inspection system(s) is used for quality control in order to check
for defects.
[0048] Reagent 80 is compounded and applied in a liquid form to the
center of array 50 at a dispensing and drying station. Reagent 80
can be applied bellowed dispenser commercially available from
Fluilogic Systems Oy, Espoo, Findland. It is appreciated that
reagent may be applied to array 50 in a liquid or other form and
dried or semi-dried onto the center of array 50 in accordance with
this disclosure.
[0049] In addition, a roll or top plate element material is fed
into a punching station to punch out contours of tab 56 in top
plate element material. Next, the top plate element material is fed
into an assembly station along with a roll of spacer material.
Liners on either side of the spacer material are removed in that
station and the top plate element is applied to one side of the
spacer material to form a top plate element/spacer subassembly. The
top plate element/spacer subassembly is slit into the appropriate
width for a row of biosensors 10. Next, a new release liner is
added to the side of the spacer material opposite the cover and the
subassembly is wound into a roll. It is appreciated that any number
of commercially available dispense units, cutting units, and sensor
punch units may be used to form biosensor 10 in accordance with
this disclosure.
[0050] The ribbon of the reagent-coated bottom plate element is
unwound and fed into a sensor assembly station along with the top
plate element/spacer subassembly. The liner is removed from the
spacer and the subassembly is placed on bottom plate element 14 to
cover reagent 80. Next, the assembled material is cut to form
individual biosensors 10, which are sorted and packed into vials,
each closed with a stopper containing desiccant, to give packaged
sensor strips.
[0051] The processes and products described above include a
disposable biosensor, especially for use in diagnostic devices.
Also included, however, are electrochemical sensors for
non-diagnostic uses, such as measuring an analyte in any
biological, environmental, or other sample. As discussed above,
biosensor 10 can be manufactured in a variety of shapes and sizes.
Non-limiting examples of which are illustrated in FIGS. 4-13. Each
of the biosensors illustrated in FIGS. 4-13 are formed similarly to
biosensor 10, except for the shape of their tabs.
[0052] Referring now to FIG. 4, biosensor 110 includes top and
bottom plates 112, 114 separated by a spacer 115. Plates 112, 114
are each formed to include a rectangular-shaped tab 116. Tab 116
includes lateral borders 118, 120 and an end 122. Illustratively,
borders 118, 120 are generally parallel relative to one another and
have a first dimension 124 that is greater than the second
dimension 126 of end 122. It is appreciated that the relative
dimensions between first and second dimensions 124, 126 may vary in
accordance with this disclosure so long as first dimension 124 is
greater than second dimension 126.
[0053] As shown in FIG. 5, biosensor 150 includes top and bottom
plates 152, 154 separated by a spacer 164. Plates 152, 154 are each
formed to include a curved tab 156. Tab 156 includes curved lateral
borders 158, 160 that meet at an end 162. It is appreciated that
borders 158, 160 can be formed with a variety of degrees of
curvature in accordance with this disclosure.
[0054] Biosensor 200 is provided in accordance with another aspect
of this invention and is illustrated in FIG. 6. Biosensor 200
includes top and bottom plates 212, 214 separated by a spacer 224.
Plates 212, 214 are each formed to include a tab 216. Tab 216
includes lateral borders 218, 220 and an end 222. Illustratively,
borders 218, 220 diverge toward end 222. It is appreciated that
borders 218, 220 can be formed to have a variety of degrees of
divergence relative to one another in accordance with this
disclosure.
[0055] Biosensor 250 is shown in FIG. 7 and includes top and bottom
plates 252, 254 separated by a spacer 264. Plates 252, 254 are each
formed to include a tab 256. Tab 256 includes generally straight
lateral borders 258, 260 and an end 262. Borders are positioned
generally parallel relative to one another and end 262 is generally
concave in shape. It is appreciated that end 262 with a variety of
degrees of curvature, or may be indented in any number of manners
in accordance with the disclosure.
[0056] Referring now to FIG. 8, biosensor 300 includes top and
bottom plates 312, 314, which are separated from one another by a
spacer 316. Each plate 312, 314 has opposite ends 318, 320 and
opposite lateral borders 322, 324. Additionally, ends 320 and a
portion 326 of lateral borders 322, 324 define a fluid
sample-receiving portion in communication with the capillary space.
It is appreciated that the length of portion 326 of lateral borders
322, 324 may vary in accordance with this disclosure.
[0057] As shown in FIG. 9, biosensor 350 includes top and bottom
plates 352, 354, which are separated from one another by a spacer
368. Plates 352, 354 are each formed to include a tab 356. Tab 356
includes lateral borders 358, 360 that include a first tapered
portion 362 and a second portion 364 extending between tapered
portion 362 and an end 366. It is appreciated that the angle of
first taper portion 362 as well as the length of second portion 364
can vary in accordance with this disclosure.
[0058] Further, as shown in FIG. 10, biosensor 400 includes top and
bottom plates 412, 414, which are separated from one another by a
spacer (not shown). Plates 412, 414 are each formed to include a
tab 416. Tab 416 includes lateral borders 418, 420 that converge
toward end 422. It is appreciated that borders 418, 420 can
converge toward one another at a variety of angles in accordance
with this disclosure.
[0059] FIG. 11 illustrates biosensor 450 in accordance with this
invention. Biosensor 450 includes a top plate 452 and a bottom
plate (not shown), which are separated from one another by a spacer
456. Each plate has a concave-shaped first end 458 and opposite
lateral borders 460, 462. Additionally, ends 458 and a portion 464
of lateral borders 460, 462 define a fluid sample-receiving portion
in communication with the capillary space.
[0060] FIG. 12 illustrates biosensor 500 in accordance with this
invention. Biosensor 500 includes a top plate 502 and a bottom
plate 504, which are separated from one another by a spacer (not
shown). Plates 502, 504 are each formed to include a tab 506. Tab
506 includes lateral borders 508, 510, and a free end 512. End 512
includes a plurality of V-shaped notches 514 therein. It is
appreciated end 512 can include any number of notches formed in a
variety of shapes and sizes in accordance with this disclosure.
[0061] FIG. 13 illustrates biosensor 550 in accordance with this
invention. Biosensor 550 includes a top plate 552 and a bottom
plate 554, which are separated from one another by a spacer (not
shown). Plates 550, 552 are each formed to include a tab 556. Tab
556 includes lateral borders 558, 560, and a free end 562. Borders
558, 560 and end 562 include a plurality of concave notches 564
therein. It is appreciated borders 558, 560 and end 562 can each
include any number of notches formed in a variety of shapes and
sizes in accordance with this disclosure.
[0062] Although the invention has been described in detail with
reference to a preferred embodiment, variations and modifications
exist within the scope and spirit of the invention as described and
defined in the following claims.
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