FIELD OF THE INVENTION
[0001] The present invention relates in general to a device and method for testing biological
samples for an analyte of interest. More particularly, the present invention relates
to a device and method for testing biological samples, such as blood, plasma, serum,
urine, or saliva samples, that makes use of a reaction chamber and a housing that
can be placed in fluid communication with one another and used to create a convenient
platform for mixing, incubating, and depositing a reaction mixture onto a test strip
in a test cassette.
BACKGROUND OF THE INVENTION
[0002] immunoassay devices that make use of immunochromatography are often utilized as a
means to test a biological sample for the presence of an analyte of interest, such
as a drug of abuse. For example, in many of these immunoassay devices and methods,
a specified volume of a biological sample can be contacted with one end of a test
strip that contains a colored reagent and that also contains an antigen or antibody
dried to the test strip in discrete zones. In this regard, as the biological sample
is wicked up by the test strip, the analyte in the sample reacts with the antigens
or antibodies and any reactions, if present, can then simply be observed by the appearance
or non-appearance of color in the discrete zones.
[0003] Given the relative ease with which the immunoassay results can be read, a number
of immunoassay devices and methods have been developed to date that allow for the
rapid screening of drugs of abuse or other analytes of interest in biological fluids.
Many of these prior immunoassay devices and methods, however, have required significant
pre-treatment steps where the biological sample must first be modified with specific
reagents to dilute or denature any interferents, to modify the analyte structure,
and/or to release the analyte from binding molecules prior to adding the biological
sample to the testing device. Additionally, in many of these prior devices and methods,
once the test sample is introduced, there has been no control provided over either
the speed or the timing of the subsequent immunoassay reactions. lndeed, in a number
of the prior devices and methods, the quantity of the reaction mixture placed in the
testing device is the major factor that determines the speed and timing of all of
the subsequent reactions and, in many instances, this ultimately leads to an inefficient
or inaccurate result.
[0004] Accordingly, a device and method for testing a biological sample for an analyte of
interest, such as a drug of abuse, that allows for not only control over the biological
sample being tested, but that also allows for the quick and accurate testing of drugs
of abuse or other analytes of interest would be both highly-desirable and beneficial.
SUMMARY OF THE INTENTION
[0005] It is thus an object of the present invention to provide a quick and accurate device
and method for testing for an analyte of interest in a variety of biological samples,
such as blood, plasma, serum, urine, or saliva samples, in a controlled manner.
[0006] These and other objects are provided by virtue of the present invention which comprises
devices and methods for testing biological samples for an analyte of interest. In
one exemplary embodiment of the present invention, a device for testing a biological
sample is provided that includes a first reaction chamber and a second reaction chamber,
where each reaction chamber has an interior wall that defines an open top of each
reaction chamber and that further defines a cavity for receiving a reaction mixture.
The device further includes a housing that is positioned below the first reaction
chamber and the second reaction chamber. The housing includes a top portion, a bottom
portion, a back wall, and two opposing side walls that define an open end of the housing
as well as an interior insertion area that is designed to receive a test cassette
containing a test strip for determining an amount of the analyte of interest in the
biological sample.
[0007] To facilitate the contacting of the test strip with the reaction mixture, which includes
the biological sample being tested, a pair of doors are positioned in the top portion
of the housing, and each door includes a ramp that extends downwardly into the insertion
area of the housing. In this regard, when the ramp is biased upward, such as by the
insertion of the test cassette into the insertion area of the housing, the doors are
opened into the cavity of their respective reaction chambers and the reaction chambers
are placed in fluid communication with the insertion area. In certain embodiments
of the devices of the present invention, each door includes a perimeter portion that
is configured to easily separate from the top portion of the housing when each ramp
is biased upward. In some embodiments, to further facilitate the opening of the doors,
each ramp includes a front edge that is angled away from the open end of the housing
such that, as a test cassette is inserted into the insertion area, the test cassette
progressively engages the angled front edge of each ramp and progressively pushes
the doors upward into each reaction chamber.
[0008] To prevent a test cassette from being prematurely inserted too far into the insertion
area of the housing and prematurely contacting the ramps on the doors of the housing,
and to also secure a test cassette in the insertion area, a pair of stops are further
included in the housing. Generally, the stops are positioned on the top portion of
the housing and extend downwardly into the insertion area such that the stops initially
provide some resistance to the insertion of the test cassette, but then suitably engage
a portion of the test cassette and secure it within the insertion area as the test
cassette is fully inserted. In some embodiments, a guide is also attached to each
side wall of the housing and is used to further secure the test cassette within the
housing, while also preventing the test cassette from being inserted too far into
the housing and prematurely contacting the ramps on the doors of the housing. In some
embodiments, the guides are additionally used to align the reaction wells of the test
cassettes underneath the doors such that, upon opening the doors into the cavities
of their respective reaction chambers and placing the reaction chambers in fluid communication
with the insertion area, the reaction mixtures flow down directly into the reaction
wells of the test cassette.
[0009] With regard to the test cassette itself, each test cassette generally includes: a
top cover that defines two reaction wells for receiving the reaction mixture from
the reaction chambers and two windows for reading test results; a base that is configured
to attach to the top cover; and at least one test strip that is interposed between
the top cover and the base. As noted above, the two reaction wells are typically positioned
on the top cover such that each reaction well can be aligned with each door in the
top portion of the housing to allow the reaction mixture to flow directly into each
reaction well upon opening the doors. To facilitate the flow of the reaction mixture
into the reaction wells, in some embodiments, the top cover further includes a bridge
that is positioned across each reaction well and provides support for the ramp upon
the insertion of the test cassette into the insertion area. In this regard, instead
of the ramp falling into the reaction well when the test cassette is inserted into
the insertion area, the bridges allow the ramps to remain biased upward and the doors
to remain open such that the reaction mixture can continue to flow into each reaction
well upon the insertion of the cassette.
[0010] To further facilitate the testing of a biological sample using the device of the
present invention, in certain embodiments, a cap is further provided for covering
the open top of the first reaction chamber and the open top of the second reaction
chamber. In some embodiments, the cap is connected to the housing by a flexible arm.
In certain embodiments, the flexible arm includes a notch that is positioned in the
flexible arm such that bending the flexible arm at the notch allows the cap to be
aligned with the open top of the first reaction chamber and the open top of the second
reaction chamber. Once the cap is aligned with the top of the reaction chambers, the
cap can then be easily placed down onto the reaction chambers and secured to the reaction
chamber by various means to allow for the mixing and/or incubating of a biological
sample and one or more reagents as part of a particular test for an analyte of interest.
[0011] Further provided by the present invention are methods for testing a biological sample
for an analyte of interest. In one exemplary implementation of a method for testing
a biological sample for an analyte of interest, a device of the present invention
is first provided that includes: a reaction chamber having an interior wall defining
an open top and a cavity for receiving a reaction mixture; a housing positioned below
the reaction chamber, and having a top portion, a bottom portion, a back wall, and
two opposing side walls defining an open end and an insertion area for receiving a
test cassette; and a door that is positioned in the top surface of the housing and
includes a ramp that extends downwardly into the insertion area.
[0012] Subsequent to the providing the device, a biological sample and one or more reagents
are placed into the cavity to thereby create a desired reaction mixture. Then, following
a suitable mixing and/or incubation period that, in certain embodiments, can be facilitated
by the placement of a cap over the open top of the reaction chamber, an immunoassay
test cassette is inserted into the insertion area such that the test cassette biases
the ramp upwards and opens the door into the cavity of the reaction chamber. Once
the door is opened, the reaction mixture is then allowed to flow into the reaction
well of each test cassette and onto an immunoassay test strip. Then, the results of
the test are read and an amount of the analyte of interest in the biological sample
is determined by analyzing the results through the windows in the test cassette. In
some embodiments, and as indicated above, the methods of the present invention are
useful for determining the amounts of a drug of abuse, including, but not limited
to, amphetamines, benzodiazepines, cocaine, methadone, methamphetamines, phencyclidine,
and tetrahydrocannabinol, in a biological sample.
[0013] Each of these embodiments and implementations of the devices and methods of the present
invention, as well as other alternatives and modifications within the spirit and scope
of the presently-disclosed invention, will become readily apparent to those of ordinary
skill in the art after a study of the description and Figures in this document.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0014]
FIG. 1 is a perspective view of a device for testing biological samples made in accordance
with the present invention;
FIG. 2 is another perspective view of the device shown in FIG. 1, but further illustrating
the bottom of the device;
FIG. 3 is yet another perspective view of the device shown in FIG. 1, but further
illustrating the top of the device;
FIG. 4 is also another perspective view of the device shown in FIG. 1, but further
illustrating the side of the device opposite that shown in FIG. 1;
FIGS. 5A-5B include perspective views of a top cover (FIG. 5A) and a base (FIG. 5B)
of an exemplary test cassette used in accordance with the present invention;
FIGS. 6A-6B include perspective views of a top cover (FIG. 6A) and a base (FIG. 6B)
of an alternative exemplary test cassette used in accordance with the present invention;
FIG. 7 is another perspective view of the exemplary test cassette shown in FIGS. 5A-5B,
but further illustrating the top cover and the base attached to one another with a
test strip interposed between the top cover and the base;
FIG. 8 is a cross-sectional view of another device for testing biological samples
made in accordance with the present invention, and illustrating a test cassette that
includes a bridge with a low height inserted into the insertion area of the housing
of the device;
FIG. 9 is a cross-sectional view of yet another device for testing biological samples
made in accordance with the present invention, and illustrating a test cassette that
includes a bridge with an intermediate height inserted into the insertion area of
the housing of the device;
FIG. 10 is a cross-sectional view of a further device for testing biological samples
made in accordance with the present invention, and illustrating a test cassette that
includes a bridge with a high height inserted into the insertion area of the housing
of the device; and
FIG. 11 is a flow chart illustrating the steps included in an exemplary method for
testing a biological sample for an analyte of interest in accordance with the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] In accordance with the present invention, devices and methods for testing a biological
sample are provided. In particular, the present invention provides devices and methods
for testing biological samples, such as blood, plasma, serum, urine, or saliva samples,
that make use of a reaction chamber and a housing that can be placed in fluid communication
with one another and used to create a convenient platform for mixing, incubating,
and depositing a reaction mixture onto test strip in a test cassette.
[0016] Referring first to FIGS. 1-4, an exemplary device 10 for testing a biological sample
for an analyte of interest in accordance with the present invention includes a first
reaction chamber 20a and a second reaction chamber 20b. Each reaction chamber 20a,
20b includes an interior wall 22a, 22b that defines an open top 24a, 24b of each reaction
chamber 20a, 20b and further defines a cavity 26a, 26b within each reaction chamber
20a, 20b for receiving a reaction mixture, as described in further detail below. In
the device 10, each interior wall 22a, 22b is continuous such that the cavity 26a,
26b defined by each interior wall 22a, 22b is substantially cylindrical in shape.
Of course, to the extent it may be desired, reaction chambers having various other
shapes and sizes can be provided for a particular application or device without departing
from the spirit and scope of the present invention. Similarly, although the device
10 includes a first reaction chamber 20a and a second reaction chamber 20b, it is,
of course, contemplated that an exemplary device can be provided with any number of
reaction chambers without departing from the spirit and scope of the present invention.
For example, it is contemplated that a device for testing a biological sample can
be provided in accordance with the present invention where the device includes a single
reaction chamber or includes three or more reaction chambers.
[0017] Regardless of the number of reaction chambers included in an exemplary device, however,
and referring now to FIGS. 1-4 and FIG. 7, the device 10 further includes a housing
30 that is positioned below the first reaction chamber 20a and the second reaction
chamber 20b. The housing 30 includes a top portion 31, a bottom portion 32, a back
wall 33, and two opposing side walls 34, 35 that define an open end 36 and an insertion
area 37 for receiving a test cassette 50 including reaction wells 54a, 54b, as also
described in further detail below. Additionally, the housing 30 includes a pair of
doors 40a, 40b that are positioned in the top portion 31 of the housing 30. Each door
40a, 40b includes a ramp 42a, 42b that extends downwardly into the insertion area
(e.g., in a direction perpendicular to the doors 40a, 40b). In this regard, when each
ramp 42a, 42b is biased upward, such as by the insertion of the test cassette 50 into
the insertion area 37, the doors 40a, 40b are opened into the cavities 26a, 26b of
their respective reaction chambers 20a, 20b and the reaction chambers 20a, 20b are
placed in fluid communication with the insertion area 37.
[0018] To facilitate the opening of the doors 40a, 40b, each door 40a, 40b further includes
a perimeter portion 44a, 44b that is configured to separate from the top portion 31
of the housing 30 when each ramp 42a, 42b is biased upwards and the doors 40a, 40b
are opened. For example, in certain embodiments, during the construction of the devices
for testing a biological sample, the perimeter portions 44a, 44b of the doors 40a,
40b can be molded from a very thin section of material such that only a small amount
of force needs to be applied to the ramps 42a, 42b to separate the doors 40a, 40b
from the remainder of the top portion 31 of the housing 30 at the location of the
perimeter portions 44a, 44b.
[0019] To further facilitate the opening of the doors 40a, 40b of the device 10, each ramp
42a, 42b includes a front edge 45a, 45b that is angled away from the open end 36 of
the housing 30. By angling the front edges 45a, 45b away from the open end 36 of the
housing 30, the triangular-shaped ramps 42a, 42b are thus configured such that, as
a test cassette 50 is inserted into the insertion area 37, the test cassette 50 progressively
engages the angled front edge 45a, 45b of each ramp 42a, 42b and progressively pushes
the doors 40a, 40b upward into the reaction chambers 20a, 20b.
[0020] To prevent the test cassette 50 from being prematurely inserted too far into the
insertion area 37 of the housing 30 and prematurely contacting the ramps 42a, 42b
on the doors 40a, 40b of the housing 30, and to also secure the test cassette 50 in
the insertion area 37 of the housing 30, the housing 30 also includes a pair of stops
60a, 60b. Generally, the stops 60a, 60b are positioned on the top portion 31 of the
housing 30 and extend downwardly into the insertion area 37 such that, upon insertion
of the test cassette 50 in the housing 30, the stops 60a, 60b initially provide some
resistance to the insertion of the test cassette 50. However, upon further insertion
of the test cassette 50, the stops 60a, 60b then suitably engage a portion of the
test cassette 50 to thereby secure the test cassette 50 within the housing 30 and
prevent the test cassette 50 from falling out of the housing 30 during use. To further
secure the test cassette 50 in the housing 30, and also prevent the test cassette
50 from being inserted too far into the housing 30 and prematurely contacting the
ramps 42a, 42b, the housing 30 also includes a guide 64, only one of which is shown
in FIG. 4, that is attached to each side wall 34, 35 of the housing 30. In this regard,
when the test cassette 50 is inserted in the insertion area 37 of the housing 30,
the test cassette 50 also initially encounters some resistance from the guides 64,
but, upon application of a slight amount of force, the test cassette 50 can then be
slidably disposed into the guides 64 such that the guides 64 hold the test cassette
50 within a particular position in the insertion area 37 while the stops 60a, 60b
are pushing against the test cassette 50 to thereby secure the test cassette 50 in
the insertion area 37. Additionally, by completely inserting the test cassette 50
into the insertion area 37 along the guides 64, the guides 64 act to align the reaction
wells 54a, 54b underneath the doors 40a, 40b. Once the reaction wells 54a, 54b of
the test cassette are aligned underneath the doors 40a, 40b, upon opening the doors
40a, 40b into the cavities 26a, 26b of the reaction chambers 20a, 20b and placing
the reaction chambers 20a, 20b in fluid communication with the insertion area 37,
the reaction mixtures within the reaction chambers 20a, 20b can simply flow directly
into the reaction wells 54a, 54b of the test cassette 50.
[0021] With further regard to the test cassette 50 itself, and referring now to FIGS. 5A-5B
and FIG. 7, for use in the exemplary embodiment of the device 10 described above,
each test cassette 50 generally includes a top cover 52, as shown in FIG. 5A, and
a base 58 that is configured to attached to the top cover 52, as shown in FIG. 5B.
Various means known to those of ordinary skill in the art can, of course, be used
for attaching the base 58 of the test cassette 50 to the top cover 52 of the test
cassette 50. In the exemplary test cassette 50 shown in FIGS. 5A-5B and FIG. 7, however,
to attach the base 58 to the top cover 52 of the test cassette 50, the top cover 52
includes a series of posts 57 that can be inserted into a series of apertures 59 in
the base 58 and used to attach (e.g., snap) the base 58 to the top cover 52.
[0022] Referring now to only FIG. 7, each test cassette 50 also includes a test strip 53
that is interposed between the top cover 52 and the base 58 prior to attaching the
base 58 to the top cover 52. In this regard, when the test strip 53 is interposed
between the base 58 and the top cover 52 and the base 58 and top cover 52 are attached
to one another, the base 58 and the top cover 52 act to secure the test strip 53 in
a desired position within the base. Various test strips known and routinely used by
those of ordinary skill in the art for testing for an analyte of interest in a biological
sample can be used in accordance with the present invention, and can be selected for
a particular application depending on the particular analyte to be detected. In some
embodiments, the test strips comprise an immunoassay test strip, such as those described
in
U.S. Patent Nos. 6,406,922,
7,090,803, and
7,695,953, each of which is incorporated herein by this reference.
[0023] Regardless of the particular test strip utilized, however, and referring again to
FIGS. 5A-5B and FIG. 7, the two reaction wells 54a, 54b are typically positioned at
a distal end 51 of the top cover 52, such that each reaction well 54a, 54b can be
aligned with each door 40a, 40b in the top portion 31 of the housing 30 upon placing
the test cassette 50 in the insertion area 37 of the housing 30, as described further
below. To facilitate the flow of the reaction mixture from the reaction chambers 20a,
20b through the doors 40a, 40b into the reaction wells 54a, 54b, the top cover 52
further includes a pair of bridges 55a, 55b, where each bridge 55a, 55b is positioned
over a reaction well 54a, 54b to provide support for the ramp 42a, 42b upon insertion
of the test cassette 50 into the insertion area 37. In this regard, instead of each
ramp 42a, 42b falling into the reaction wells 54a, 54b when the test cassette 50 is
inserted into the insertion area 37, the bridges 55a, 55b allow the ramps 42a, 42b
to remain biased upward such that the reaction mixture can continue to flow into each
reaction well 54a, 54b at a controlled rate upon the insertion of the cassette 50.
[0024] For example, to provide a device in which the reaction mixture flows from the wells
at a desired rate, and referring now to FIGS. 8-10, in one exemplary embodiment, a
device 210 for testing a biological sample is provided that includes a bridge 255a
having a low height such that, upon insertion of the test cassette 250, the bridge
255a supports the ramp 242a and the door 240a of the housing 230 in a position where
the door 240a is only opened slightly into the reaction chamber 220a and where only
a minimal amount of reaction mixture is able to flow from the reaction chamber 220a
at a given time. As another example, in another exemplary embodiment, a device 310
for testing a biological sample is provided that includes a bridge 355a having an
intermediate height such that, upon insertion of the test cassette 350, the bridge
355a supports the ramp 342a and the door 340a of the housing 330 in a position where
the door 340a is opened into the reaction chamber 320a in a manner that allows the
reaction mixture to flow from the reaction chamber 320a at an intermediate rate. As
yet another example, in yet another exemplary embodiment, a device 410 for testing
a biological sample is provided that includes a bridge 455a having an increased height
such that, upon insertion of the test cassette 450, the bridge 455a supports the ramp
442a and the door 440a of the housing 430 in a position where the door 440a is fully
opened into the reaction chamber 420a to thereby allow the reaction mixture to flow
from the reaction chamber 420a at faster rate. Of course, other devices that make
use of test cassette bridges having various other heights are also contemplated to
be within the spirit and scope of the present invention, and can be easily selected
to provide a particular flow rate for a particular application.
[0025] Regardless of the particular flow rate provided for a particular application, and
referring again to FIGS. 5A-5B and FIG. 7, once the reaction mixture flows from each
reaction chamber 20a, 20b into the reaction wells 54a, 54b of the test cassette, the
reaction mixtures are typically wicked up by the test strip 53. The test strip 53
then allows the reaction mixture to laterally flow along the test strip 53 such that
the results of the particular test can be read and the amount of the analyte in the
biological sample can be determined by analyzing the results of the test through windows
56a, 56b in the test cassette 50.
[0026] With further regard to the test cassettes of the present invention, it is appreciated
that the number of reaction wells in a particular test cassette can also be varied
and that test cassettes having various numbers of reaction wells can be provided for
a particular application or for a particular device such that the number of reaction
wells in the test cassette corresponds with the number of reaction chambers included
in an exemplary device. For example, and referring now to FIGS. 6A-6B, in some embodiments,
a test cassette is provided that, like the exemplary test cassette 50 shown in FIGS.
5A-5B and FIG. 7, includes a top cover 152 and a base 158 as well as a series of posts
157 and apertures 159 for connecting the top cover 152 to the base 158. However, unlike
the test cassette 50, the top cover 152 only includes a single reaction well 154 for
receiving a reaction mixture and a single window 156 for reading a test result. In
other words, the test cassette formed by the attachment of the top cover 152 to the
base 158 would be configured for use with a device of the present invention having
only a single reaction chamber.
[0027] Finally, and referring again to FIGS. 1-4, each device 10 also includes a cap 70
for covering the open top 24a of the first chamber 20a and the open top 24b of the
second chamber 20b. The cap 70 is connected to the housing 30 by a flexible arm 72,
which includes a notch 74. The notch 74 is positioned in the flexible arm 72 such
that bending the flexible arm 72 at the notch 74 allows the cap 70 to be aligned with
the open top 24a of the first reaction chamber 20a and the open top 24b of the second
reaction chamber 20b. Once the cap 70 is aligned with each open top 24a, 24b, the
cap 70 can then be easily placed onto the reaction chambers 20a, 20b and secured to
each reaction chamber 20a, 20b.
[0028] As described in further detail below, by securing the cap 70 to the reaction chambers
20a, 20b, the cap 70 provides a convenient means to cover each reaction chamber 20a,
20b and provide a closed environment to thereby facilitate the mixing and/or incubating
of a biological sample and one or more reagents. Various means, including gaskets,
threaded portions, and the like, can, of course, be included on the cap 70 to secure
the cap 70 to the reaction chambers 20a, 20b. In some embodiments, and as shown in
FIGS. 1-4, the cap 70 of the device 10 includes raised portions 75, 77 that are configured
to matingly engage corresponding depressions 76, 78 defined by the interior walls
22a, 22b of the reaction chambers 20a, 20b to thereby secure the cap 70 to the reaction
chambers 20a, 20b.
[0029] Referring now to FIG. 11, further provided by the present invention are methods for
testing a biological sample for an analyte of interest. In this exemplary implementation,
and as indicated by block 500, the testing commences by providing a device for testing
a biological sample that includes a reaction chamber having an interior wall defining
an open top and a cavity for receiving a reaction mixture; a housing positioned below
the reaction chamber, and having a top portion, a bottom portion, a back wall, and
two opposing side walls defining an open end and an insertion area for receiving a
test cassette; and a door that is positioned in the top surface of the housing and
includes a ramp that extends downwardly into the insertion area.
[0030] Subsequent to providing the device, a biological sample and one or more reagents
are placed into the cavity of each reaction chamber to thereby create a suitable reaction
mixture, as indicated by block 510. With regard to the biological samples used in
accordance with the present invention, the biological sample can include any body
fluid or tissue in which an analyte of interest can be detected, including, but not
limited to, blood, plasma, serum, urine, or oral fluid samples. In some embodiments,
for example, the biological sample is an oral fluid sample, such as a saliva sample.
[0031] Typically, the one or more reagents include a suitable buffer solution and a suitable
identifying reagent that is capable of targeting a particular analyte of interest,
such as a drug of abuse. For example, in certain embodiments, a buffer solution that
assists in the removal or reduction of interferents that may patentially interfere
with the detection of the analyte of interest can be used along with a gold particle
attached to a suitable antibody or antigen that is used to target the particular analyte
of interest, as described in
U.S. Patent No. 7,695,953. In certain embodiments of the present invention, where the analyte of interest is
a drug, such as a drug of abuse, the drugs targeted by the antibody or antigen can
be any drug or other compound of interest that can be detected in a biological sample.
Such drugs include, but are not limited to, amphetamines, benzodiazepines, cocaine,
methadone, methamphetamines, phencyclidine (PCP), and tetrahydrocannabinol (THC).
In some embodiments, and as also described in
U.S. Patent No. 7,695,953, a gold-labeled antibody specific to the target drug can be provided in the reaction
chamber, e.g., in dry form, prior to the addition of the buffer solution and biological
sample to the reaction chamber.
[0032] Once the biological sample and the one or more reagents are added to the cavity of
the reaction chamber of the device, the biological sample and the reagents are generally
mixed together, as indicated by block 520, and allowed to incubate for a suitable
time period such that the identifying reagent has sufficient time to target and bind
to the analyte of interest. In certain embodiments, to promote the mixing of the reagents
and/or to promote the breakdown of any interfering molecules, the device can be slightly
shaken or otherwise agitated by gently moving the device from side to side on a flat
surface. In other embodiments, the cap of the devices is used to cover the open tops
of the reaction chambers such that more vigorous shaking can be used to mix the reaction
mixtures as needed. In yet further embodiments, the biological sample can be mixed
with a suitable buffer solution prior to placing the biological sample and buffer
mixture into the reaction chamber and combining it with the reagents (e.g., reagents
that are provided in a dried form in the reaction chamber).
[0033] Once the biological sample and the reaction mixtures have been mixed, and following
a suitable incubation period, an immunoassay test cassette, which includes a test
strip specific for the analyte to be detected, is inserted into the insertion area
of the device, as indicated by block 530. In inserting the immunoassay test cassette
into the insertion area, the test cassette is first pushed past the stops included
in the top portion of the housing of the device and is inserted along the guides in
each opposing side wall to thereby secure the cassette in the housing and to align
the reaction wells of the cassette with the doors included in the top portion of the
housing. In this regard, as the test cassette is pushed into the insertion area of
the housing, the test cassette initially begins to encounter the angled front edge
of the ramps extending downwardly from the doors. As the test cassette then moves
further inward, the triangular shape of the ramp progressively engages the test cassette
and the perimeter portion of the door eventually breaks away from the remainder of
the top portion of the housing and allows the doors to be opened into the reaction
chamber. The upward movement of the door into the reaction chamber then allows the
reaction mixture to flow downward through the doors into the reaction wells of the
test cassette and onto the test strip that is interposed between the top cover and
the base of the test cassette.
[0034] Once the reaction mixture flows down into reaction wells and onto the test strip,
the reaction mixture is then wicked up by the test strip and laterally flows along
the test strip such that the results of the test can be read and the amount of analyte
in the biological sample can be determined by analyzing the results of the test through
the windows of the test cassette, as indicated by block 540. In some implementations
of the methods for testing a biological sample for an analyte of interest, determining
an amount of an analyte of interest, such as a drug of abuse, in a biological sample
can include only a qualitative assessment of the presence or absence of the analyte
of interest in the biological sample. In other implementations of the methods of the
present invention, however, a quantitative assessment of the amounts of the analyte
of interest in the biological sample can be made, Such quantitative assessments can
be made by various techniques known to those of ordinary skill in the art.
[0035] The above-described devices and methods for testing a biological sample that make
use of a reaction chamber and a housing, which are capable of being placed in fluid
communication with one another, thus provide a convenient platform for mixing, incubating,
and depositing a reaction mixture onto test strip in a test cassette, with the added
benefit that the reaction chambers and housing allow for a controlled release of a
reaction mixture onto a test cassette in a manner that provides a quick and accurate
testing for drugs of abuse or other analytes of interest.
[0036] One of ordinary skill in the art will recognize that additional embodiments are also
possible without departing from the teachings of the presently-disclosed subject matter.
This detailed description, and particularly the specific details of the exemplary
embodiments disclosed herein, is given primarily for clarity of understanding, and
no unnecessary limitations are to understood therefrom, for modifications will become
apparent to those skilled in the art upon reading this disclosure and may be made
without departing from the spirit or scope of the presently-disclosed subject matter.
1. A device for testing a biological sample, comprising:
a reaction chamber having an interior wall defining an open top and a cavity for receiving
a reaction mixture;
a housing positioned below the reaction chamber, the housing having a top portion,
a bottom portion, a back wall, and two opposing side walls defining an open end and
an insertion area for receiving a test cassette; and
a door positioned in the top portion of the housing and including a ramp downwardly
extending into the insertion area such that biasing the ramp upwards opens the door
into the cavity of the reaction chamber and places the reaction chamber in fluid communication
with the insertion area.
2. The device of claim 1, wherein the door includes a perimeter portion configured to
separate from the top portion of the housing upon biasing the ramp upwards or wherein
a front edge of the ramp is angled away from the open end of the housing.
3. The device of claim 1, further comprising a stop positioned on the top portion of
the housing and extending downwardly into the insertion area, the stop for securing
the test cassette in the insertion area.
4. The device of claim 1, further comprising a guide attached to each side wall of the
housing for aligning the test cassette in the insertion area.
5. The device of claim 1, wherein the test cassette comprises:
a top cover defining a reaction well for receiving the reaction mixture from the reaction
chamber and further defining a window for reading a test result;
a base configured to attach to the top cover; and
a test strip interposed between the top cover and the base.
6. The device of claim 5, wherein the reaction well is positioned on the top cover such
that the reaction well is aligned with the door upon placing the test cassette into
the insertion area.
7. The device of claim 5, wherein the top cover includes a bridge positioned across the
reaction well, the bridge for supporting the ramp upon placing the test cassette into
the insertion area.
8. The device of claim 1, further comprising a cap for covering the open top of the reaction
chamber.
9. The device of claim 8, wherein the cap is connected to the housing by a flexible arm.
10. The device of claim 9, wherein the flexible arm includes a notch positioned in the
flexible arm such that bending the flexible arm at the notch allows the cap to be
aligned with the open top of the reaction chamber.
11. The device of claim 8, wherein the cap includes a means for securing the cap to the
reaction chamber.
12. A device for testing a biological sample, comprising:
a first reaction chamber and a second reaction chamber, each reaction chamber having
an interior wall defining an open top and a cavity for receiving a reaction mixture;
a housing positioned below the first reaction chamber and the second reaction chamber,
the housing having a top portion, a bottom portion, a back wall, and two opposing
side walls defining an open end and an insertion area for receiving a test cassette;
and
a pair of doors positioned in the top portion of the housing, each door including
a ramp downwardly extending into the insertion area such that biasing the ramp upwards
opens the door into the cavity of each reaction chamber and places each reaction chamber
in fluid communication with the insertion area.
13. The device of claim 12, wherein each door includes a perimeter portion configured
to separate from the top portion of the housing upon biasing each ramp upwards.
14. The device of claim 12, wherein a front edge of each ramp is angled away from the
open end of the housing.
15. The device of claim 12, further comprising a pair of stops positioned on the top portion
of the housing and extending downwardly into the insertion area, the stops for securing
the test cassette in the insertion area.
16. The device of claim 12, further comprising a guide attached to each side wall of the
housing for aligning the test cassette in the insertion area.
17. The device of claim 12, wherein the test cassette comprises:
a top cover defining two reaction wells for receiving each reaction mixture from each
reaction chamber and further defining two windows for reading test results;
a base configured to attach to the top cover; and
at least one test strip interposed between the top cover and the base.
18. The device of claim 12, wherein the two reaction wells are positioned on the top cover
such that each reaction well is aligned with each door in the top portion of the housing
upon placing the test cassette into the insertion area.
19. The device of claim 12, wherein the top cover includes a bridge positioned across
each reaction well, each bridge for supporting the ramp upon insertion of the test
cassette into the insertion area.
20. The device of claim 12, further comprising a cap for covering the open top of the
first reaction chamber and the open top of the second reaction chamber.
21. A method for testing a biological sample for an analyte of interest, comprising:
providing a device, including :
a reaction chamber having an interior wall defining an open top and a cavity for receiving
a reaction mixture;
a housing positioned below the reaction chamber, the housing having a top portion,
a bottom portion, a back wall, and two opposing side walls defining an open end and
an insertion area for receiving a test cassette; and
a door positioned in the top portion of the housing and including a ramp downwardly
extending into the insertion area such that biasing the ramp upwards opens the door
into the cavity of the reaction chamber and places the reaction chamber in fluid communication
with the insertion area;
placing the biological sample and one or more reagents into the cavity to thereby
create the reaction mixture;
inserting an immunoassay test cassette into the insertion area such that the test
cassette biases the ramp upwards and opens the door into the cavity of the reaction
chamber to allow the reaction mixture to contact an immunoassay test strip; and
determining an amount in the biological sample of the analyte of interest.
22. The method of claim 21, wherein the biological sample comprises blood, plasma, serum,
urine, or saliva.
23. The method of claim 21, further comprising the step of mixing the biological sample
and the one or more reagents after placing the biological sample and the one or more
reagents into the cavity.
24. The method of claim 21, further comprising the step of covering the open top of the
cavity after placing the biological sample and the one or more reagents into the cavity.
25. The method of claim 21, wherein the analyte of interest is a drug of abuse.
26. The method of claim 25, wherein the drug of abuse is selected from the group consisting
of amphetamines, benzodiazepines, cocaine, methadone, methamphetamines, phencyclidine,
and tetrahydrocannabinol.
27. A device for testing a biological sample, comprising:
a reaction chamber having an interior wall defining an open top and a cavity for receiving
a reaction mixture;
a housing positioned below the reaction chamber, the housing having a top portion,
a bottom portion, a back wall, and two opposing side walls defining an open end and
an insertion area for receiving a test cassette;
a door positioned in the top portion of the housing and including a ramp downwardly
extending into the insertion area such that biasing the ramp upwards opens the door
into the cavity of the reaction chamber and places the reaction chamber in fluid communication
with the insertion area; and
a test cassette.