WO2017083843A1

WO2017083843A1 - Driven flow and volumetric control devices and methods

Info

Publication number: WO2017083843A1
Application number: PCT/US2016/061880
Authority: WO
Inventors: Naishu Wang; Michael Chang-Chien
Original assignee: Dnt Scientific Research, Llc
Priority date: 2015-11-13
Filing date: 2016-11-14
Publication date: 2017-05-18

Abstract

Disclosed herein are diagnostic devices, in particular, specimen cups, for harmonization of enforcing driven flow and volumetric control of biological fluid mechanisms. The specimen cups include an outer cup, an inner cup with a metering hole, a crush sleeve, and a cap, where the inner cup can receive biological fluids.

Description

DRIVEN FLOW AND VOLUMETRIC CONTROL DEVICES AND METHODS

CROSS REFERENCE TO RELATED APPLICATIONS

[1] This application claims priority to U.S. Application No. 62/254,492 filed on November 13, 2015, and U.S. Application No. 62/369,971, filed on August 2, 2016, which are herein incorporated by reference in their entirety.

TECHNICAL FIELD

[2] This invention relates generally to diagnostic devices and methods for analyzing liquids, such as some body fluids, using labeled molecular affinity binding, such as immunochromatography, and more particularly to specimen cups with strip test apparatuses for detecting an analyte, such as an antibody or antigen, which may indicate a particulate condition.

BACKGROUND

[3] Rapid diagnostic devices have adopted lateral-flow immunoassay technology for more than a decade. The technology is based on a series of capillary beds which includes a sample pad, a conjugate pad, a membrane, and an absorbent pad as four basic elements. A biological fluid is carried through the conjugate pad and develops colors on the membrane for visual interpretation. Conventional testing devices take about 5-20 minutes to perform the test, depending on the time for the fluid to flow through the membrane and the volume of conjugated proteins carried by the fluid.

[4] U.S. Patent No. 9,377,457, herein incorporated by reference in its entirety discloses compression driven flow cartridges for analyte detection strips.

[5] One challenge of testing specimens with current rapid diagnostic devices is the retention of an authentic specimen in the diagnostic device for further laboratory analysis (e.g., GC/MASS or LC/MASS) in order to confirm the preliminary positive results. In order to retain an authentic specimen, some devices use valves or segregated chambers to achieve this goal.

[6] Despite the advances achieved, a continuing need exists for devices and methods of improved testing time and specimen retention for authentication. SUMMARY

[7] The invention relates generally to diagnostic devices and methods for analyzing liquids. Particularly, the invention relates to specimen cups designed and manufactured with crush and compression mechanisms to accelerate the flow speed of fluid and to force conjugated proteins to pass through the membrane. Consequently, these novel crush and compression mechanisms significantly shorten the time to complete the reaction. Reaction time is reduced from 5-20 minutes to 1-3 minutes, and even to 1 minute or less.

[8] In some specimen cups of the invention, volumetric control of the specimen may be obtained by adapting a metering hole within the inner cup, which permits the retention of an authentic specimen in the inner cup and prevents contamination of the retained authentic specimen by the testing specimen.

[9] In some specimen cups of the invention, a swellable material, such as a super-absorbent polymer (SAP) is located below the metering hole. As the specimen flows through the metering hole to contact the test strips, some of the specimen is absorbed by the swellable material causing it to swell and eventually close the metering hole. An amount of the specimen is then sealed into the portion of the outer cup and is in contact with the test strips.

[10] Specimen cups of the invention comprise five main components: a cap, a crush sleeve, one or more individual test strips, an inner cup, and an outer cup. In one embodiment, a plurality of test strips, for example, two or more individual test strips, can be used in the invention. Multiple strips may be used to test analytes with specific cutoff values.

[11] Also disclosed herein are methods for conducting liquid flow assays, such as a liquid flow immunoassay for at least one analyte, wherein said method comprises use of a specimen cup of the invention. A user assembles the components of the specimen cup device by attaching the test strips to a crush sleeve. The user inserts the test strips-crush sleeve combination concentrically into an outer cup. The user inserts an inner cup into the center of the crush sleeve-test strip combination that is in the outer cup. The user places a cap in a ready position to facilitate receiving the biological fluid. The crush function of the invention allows a strip to absorb the biological fluid quickly based on improvements in the surface area of the strip and the configuration of the device, and to preserve a retained specimen.

[12] These and other aspects of the invention will be apparent to the skilled artisan in light of the following detailed description and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[13] FIG. 1 is a front perspective view of an assembled specimen cup in accordance with the invention.

[14] FIG. 2 is an exploded view of the specimen cup device of FIG. 1.

[15] FIG. 3 shows a crush sleeve in a flat configuration.

[16] FIG. 4 shows an assembled specimen cup in accordance with the invention.

[17] FIG. 5 shows an assembled specimen cup in accordance with the invention, showing the swellable material before addition of fluid.

[18] FIG. 6 shows an assembled specimen cup in accordance with the invention, showing the swellable material after fluid addition.

DETAILED DESCRIPTION

[19] The specimen cups of the invention can be used to rapidly determine the presence of an analyte or plurality of analytes in a liquid sample at a concentration which confirms the condition being tested. The samples can include, for example, body fluids, such as whole blood, serum, plasma, urine, spinal fluid, amniotic fluid, mucous, saliva, and the like, or other fluids used in certain food and environmental testing. These fluids can be tested for physiological and biochemical states, including anemia, infection, inflammation, bleeding disorders (for example, with blood tests), protein-determined conditions (with serum and plasma tests, for example), drugs of abuse (using urine tests, for example), infectious diseases such as meningitis and encephalitis, autoimmune disorders, such as Guillain-Barre syndrome, sarcoidosis, and multiple sclerosis (using spinal fluid tests, for example), amniotic fluid, mucous, endocrine, immunologic, inflammatory, infections, Cushing's disease, anovulation, HIV, cancer, parasites, hypogonadism, and allergies (saliva), and others. These and other tests can be performed using one or more biological fluids and combinations of biological fluids.

[20] The term "analyte," as used herein, refers to a compound or composition to be observed and/or measured in a specimen cup of the invention. The presence or absence of an analyte may be determined in qualitative assay, or the amount of the analyte present may be determined in a qualitative assay. The analyte can be any substance, such as an antigen or ligand, for which there exists a naturally or genetically occurring specific binding member such as a binding molecule, such as an antibody or receptor, and other molecules that exhibit the so-called "lock-in-key" pairing function.

[21] "Analyte" also includes any antigenic substances, haptens, antibodies, and combinations thereof. The analyte can include a protein, a peptide, an amino acid, a ligand, a hormone, a steroid, a vitamin, a drug including those administered for therapeutic purposes as well as those administered for illicit purposes, a pathogen, and an exogenous infectious microbe, such as a bacterium, a virus, and metabolites of or antibodies to any of the above substances. The analyte can also comprise an antigenic marker or antibody or receptor.

[22] The precise nature of a number of analytes together with a number of examples thereof are disclosed in Litman et al., U.S. Patent No. 4,299,916, issued November 10, 1981; and Tom et al., U.S. Patent No. 4,366,241, issued December 28, 1982, each of which is hereby incorporated by reference in its entirety.

[23] The signal provided to the user of the device is provided by accumulation of a visually detectable label conjugated to a mobilizable binding member such as a specific antibody and/or antigen; ligand and/or receptor. This mobilizable binding member is sometimes referred to as a "binding member molecule," "a first affinity binding member," a "labeled binding member," or simply a "conjugate." In some embodiments, labels that produce a readily detectable signal are used. Thus, some embodiments provide colored labels which permit visible detection of the assay results without the addition of further substances and/or without the aid of instrumentation.

[24] The test strips described in the various embodiments can include regions or pads that may comprise dry porous material. By "porous" it is meant that the matrix of material forming the porous structure allows liquids to flow through it.

[25] The term "mobilizable" as referred to herein means diffusively or non-diffusively attached, or impregnated. The mobilizable reagents are capable of dispersing with the liquid sample and carried by the liquid sample in the liquid flow.

[26] Fig. 1 shows an assembled specimen cup [100] in accordance with one embodiment of the invention. Fig. 2 shows the same cup [100] in an exploded view. As outlined above, specimen cups [100] according to the invention comprise five main components: a cap [101], a crush sleeve [102], one or more individual test strips [103], an inner cup [104], and an outer cup [105]. A plurality of individual test strips, e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc. individual test strips [103], can be used. Multiple strips may be used to test analytes with specific cutoff values. Fig. 1 depicts the overall shape of an example specimen cup [100] as cylindrical, but other shapes may also be used.

[27] Specimen cups of the invention may be made of any suitable material, for example, plastics. Exemplary plastics include as polypropylene, acrylonitrile butadiene styrene, acrylonitrile styrene, and polyethylene terephthalate.

[28] In specimen cups of the invention, the diameter of the outer cup [105] should be greater than that of the inner cup [104], and the diameter of the cap [101] should be greater than that of the outer cup [105]. In one specimen cup [100] according to the invention, the outer cup [105] has a diameter of 62 mm, a height of 72.7 mm, and is able to hold a volume of 198 mL, the inner cup [104] has a diameter of 52 mm, a height of 72.7 mm, and is able to hold a volume of 98 ml, and the cap [101] has a diameter of 69.7 mm. In another specimen cup [100] according to the invention, the outer cup [105] may have a diameter of about 55-65 mm, a height of about 65-75 mm, and be able to hold a volume of about 180-210 mL, the inner cup [104] may have a diameter of about 45- 55 mm, a height of 65-75 mm (preferably the same height as the outer cup [105]), and is able to hold a volume of about 80-110 ml, and the cap [101] has a diameter of about 60-70 mm.

[29] Fig. 2 shows an exploded view of a specimen cup [100] where the test strips [103] are attached to the crush sleeve [102] and held in place by interference tabs [106] that hold the sides of the test strips [103]. In other embodiments, different retention features can retain the test strips at the proximal end on the side or top of the test strips. The crush sleeve [102] can be constructed in a flat configuration, as shown in Fig. 3, and made of flexible yet rigid material such as, for example, polypropylene or polyethylene, so as to provide a "living hinge." As shown in Figs. 2 and 3, the purpose of these living hinges [111] is to allow the flat component [191] to be bent into a circular configuration bending at the connected tabs [193] and allowing the strip features to remain flat for proper interference of the test strips for retention. Alternatively, the crush sleeve [102] can be constructed in circular configurations.

[30] The exploded view of Fig. 2 shows this crush sleeve/test strips subassembly [102, 103] can slide into the outer cup [105]. The top [192] of the crush sleeve [102] should be level with the top of the outer cup [105]. The purpose for the crush sleeve/tests strips subassembly [102, 103] is to move vertically between the inner cup [104] and outer cup [105]. In a specimen cup [100] of the invention, the inner cup [104] is located within the circumference of the circular crush sleeve [102] and should be seated on the bottom of the outer cup [105] as shown in Fig. 5. Other assembly and/or subassembly sequences are possible. The initial portion of the threads [181] on the cap [101] and the threads [182] on the outer cup [105] can engage as the cap [101] is rotated in a ready position. Prior to the addition of the biological fluid to be tested, the cap [101] is not completely rotated into a closed position.

[31] After assembly of a specimen cup [100] in a ready position, the cap [101] may be removed, and a biological fluid, for example, urine, may be introduced into the inner cup [104]. The volume of test biological fluid is exposed to the metering system of the specimen cup [100] in the inner cup [104]. As shown in Fig. 4, volumetric control of the specimen may be obtained by adapting a metering hole [107] within the inner cup [104], which permits the retention of an authentic specimen [115] in the inner cup [104] and prevents contamination of the retained authentic specimen [1 15] by the testing specimen [116] as shown in Fig. 6. The small metering hole [107] within the inner cup [104] is purposely sized to control the test biological fluid volume flowed to the test strip(s )[103]. In one embodiment, the diameter of the metering hole [107] is less than 1.5 mm, for example 1.0 mm, and even smaller, such as 0.8 mm. If the sample volume is inadequate, a known amount of an additional liquid, such as deionized, distilled, or sterile water, or buffer may be added, and the results calibrated by the dilution effect as appropriate.

[32] In some specimen cups, the metering hole may be located at the bottom of the inner cup. Fig. 4 depicts an inner cup [104] with the metering hole [107] as part of a conical feature [171] at the bottom [172] of the inner cup [104]. The conical shape leading to the metering hold [107] works well, but other shapes, for example, hemispherical or cylindrical may also be used.

[33] Apertures [114] at the outer bottom [144] of the inner cup [104] allow for fluid to flow out into the outer cup [105] and reach the test strip [103]. Fig. 2 shows the apertures [114] in a rectangular shape, but the apertures may be other shapes.

[34] In one embodiment of the invention, the user then installs the cap [101] and rotates the cap [101] until it is sealed against the outer cup [105]. The act of rotating the cap [101] to the sealed position allows a circular standing rib feature [108] in the cap [101] to act against the top surface of the crush sleeve [102] and move the crush sleeve insert [102] vertically downward into the outer cup [105]. This act also moves the test strip(s) [103] attached to the crush sleeve [102] down with it. In moving the crush sleeve insert/test strip subassembly [102, 103] down with the cap [101], the ends [151] of the test strips [103] are crushed against the bottom surface [161] of the outer cup [105] and the outer diameter [143] of the inner cup [104]. [35] In a sample cup of the invention, the threads [182] on the outer cup [105] and the threads [181] on the cap [101] are configured to provide a sufficient mechanical advantage and resultant force to crush the distal ends [151] of the test strips [103] and compress the conjugate pad portion [109] (shown in Fig. 4) of the test strips [103].

[36] This crush function of the test strips [103] allows the strips [103] to perform faster due to having more area to absorb the sample (biological fluid) quickly. At the same time, as shown in Fig. 4, this downward vertical movement also moves the conjugate pad portion [109] of the test strip over a (compression) ramp [110] and into a narrower space between the inner cup [104] and outer cup [105] compressing the conjugate pad portion [109] on the test strip [103]. This compression function of the test strips allows the strip [103] to perform faster testing due to driving the biological fluid momentarily through the conjugate pad [109] with more volume of conjugated protein.

[37] In a specimen cup [100] of the invention, when the cap [101] is rotated to its fully seated position, the threads on the cap [181] and the threads on the outer cup [182] provide a seal between the cap [101] and both the rim of the inner cup [183] and the rim of the outer cup [184]. These features seal off the void between the outer diameter [143] of the inner cup [104] and the inner diameter [162] (shown in Fig. 2) of the outer cup [105]. This seal forces the biological fluid level to be controlled by two forces, the surface tension of the fluid and void space and the surface tension of the individual test strip biological fluid and geometry.

[38] The seal between the rim of the outer cup [184] and cap [101] also prevents the test biological fluid (urine, in one example) from leaking out of the specimen cup [100]. And the seal between the rim of the inner cup [183] and cap [101] also prevents the test biological fluid (e.g., urine) from being exposed to too much test biological fluid should the sealed jar be knocked or tipped onto its side.

[39] Other sample cups of this invention can utilize a wicking biological fluid downstream of the metering hole [107] in the bottom [172] of the inner cup [104] to control the flow to the test strips [103]. In some sample cups, the bottom [161] of outer cup [105] and or the bottom [144] of the inner cup [104] may also be curved, better allowing the ends [151] of the lateral flow strips [103] to curve into the testing specimen [116].

[40] In a specimen cup [100] of the invention, as shown in Fig. 5, a swellable material [112], such as a super-absorbent polymer (SAP) is placed below the metering hole [107]. As the specimen flows through the metering hole [107] to contact the test strips [103], some of the specimen is absorbed by the swellable material [112] causing it to swell and to eventually close off the metering hole [107]. An amount of the specimen is then sealed into the testing specimen portion [163] of the outer cup [105] and is in contact with the test strips [103].

[41] As shown in Figs. 5 and 6, the swellable material [112] may be located within a retaining vessel [113] on the bottom [161] of outer cup [105]. The retaining vessel [113] contains a swellable material (i.e. SAP, superabsorbent polymer) [112]. A SAP is a polymer that can absorb and retain extremely large amounts of a liquid relative to its own mass. Example superabsorbent polymers include sodium polyacrylate, polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxymethylcellulose, polyvinyl alcohol copolymers, cross-linked polyethylene oxide, and the like. The distance between the swellable material [112] and the bottom of the metering hole [107] should be such that as the swellable material [112] swells, it reaches the bottom of the metering hole [107] and cuts off the specimen flow through the metering hole [107]. Setting up the distance between the metering hole [107] and vessel at, approximately 1.5 to 2 mm, or at about 1.7mm is demonstrated to be effective to let the swellable material, e.g. the SAP, expand against the metering hole [107] and stop the fluid flow. The amount of swellable material [112] used will also allow for more or quicker sealing of the metering hole [107]. However, the amount and type of swellable material [112] should not be such that it swells and closes the metering hole [107] before a sufficient amount of sample fluid flows through for testing.

[42] After the fluid is transferred into the inner cup, it passes through the metering hole [107] and reaches the swellable material [112], such as an SAP, located in the retaining vessel [113]. During a limited time (around 30-40 seconds), the SAP, for example, swells gradually by absorbing fluid specimen and finally blocks the metering hole [107] as shown in Fig. 6. In the meantime, there is enough fluid volume that has flowed through the metering hole [107] and reached test strips [103] and triggered the testing. Increasing the diameter of metering hole [107] from, for example about 0.8 mm to 1.5mm permits faster fluid flow and quicker testing times. In the invention, the metering hole [107] may have a diameter of about 0.8 to about 2.0 mm or about 1.0 mm to about 1.7 mm or be about 1.5 mm in diameter. A sufficient amount of swellable material should be used to seal the metering hole [107] but not so much as to absorb amounts of the specimen such that the tests do not run. Fig. 6 further shows the retention of an authentic specimen [115] in the inner cup [104] and its separation from the testing specimen [116].

[43] The presence of the swellable material [112] allows for tests to be run even in situations where the user may not fully close the cap [101]. For example, if a user forgets to close the cap [101], the tests may fail because the fluid may overflow the test strips [103] before the reading time. However, by locating a swellable material [112] below the metering hole [107], the swellable material [112], when swollen, can block the metering hole [107] within a limited time. Even if the cap [101] does not close on the specimen cup [100], the test(s) can proceed without fluid overflow. This makes this embodiment of the invention particularly suited for the over-the- counter (OTC) consumer market.

[44] A method of testing a liquid sample for at least one analyte using a specimen cup [100] according to the invention first requires assembly of the components of the specimen cup [100]. In one method of the invention, a user attaches the test strips [103] to the crush sleeve [102]. The user inserts the test strips-crush sleeve combination [102, 103] concentrically into the outer cup [105]. The user inserts the inner cup [104] into the center of the crush sleeve-test strip combination [102, 103] that is in the outer cup [105]. The user places the cap [101] in a ready position to facilitate receiving the biological fluid. Once the user is ready, the cap [101] is taken off and a biological fluid sample, for example, urine, is added to the inner cup [104]. The specimen cup may optionally display a fill mark [not shown], to indicate the volume of the fluid to be added. After the biological fluid is added, the user rotates the cap [101] to a fully closed position. The crush function of the invention allows a test strip or plurality of test strips [103] to absorb the biological fluid quickly based on improvements in the surface area of the strip [103] and the configuration of the specimen cup [100], while also preserving a retained specimen

[115]. Other assembly and/or subassembly sequences are possible. The user then waits for the appropriate time for test to develop, based on the test strip [103] configuration. The user then reads the test results after the appropriate time.

EXAMPLE

[45] The diameter of the metering hole provides for volumetric control by using the fluid pressure against the surface tension of that fluid. In Table 1, experiments were conducted in which different diameters of metering holes were adapted to test urine flow. The experiments demonstrate that when the diameter of the metering hole is over 1.5 mm, there is no retention function at all after 120 seconds. However, when shrinking the diameter of the metering hole to 1.0 mm, urine stops flowing through the metering hole after 140 seconds because the fluid pressure is less than the surface tension of urine at the metering hole. In another experiment, shrinking the diameter of the metering hole to 0.8 mm stopped the flow of urine after 90 seconds.

Table 1: Volumetric Control measurements of different sizes of metering holes

Claims

What is claimed is:

1. A specimen cup for testing a liquid sample for at least one analyte, wherein said specimen cup comprises:

a) a cap;

b) a crush sleeve;

c) one or more individual test strips positioned on the crush sleeve;

d) an inner cup; and

e) an outer cup.

2. The specimen cup of claim 1, wherein a subassembly of the specimen cup comprises the one or more individual test strips and the crush sleeve.

3. The specimen cup of claims 1 or 2, wherein one or more individual test strips are attached to the crush sleeve and held in place by interference tabs that hold the sides of one or more individual test strips.

4. The specimen cup of claim 1, wherein the crush sleeve is attached to either the inner cup or the outer cup.

5. The specimen cup of claim 1 or 2, having a metering hole within the inner cup.

6. The specimen cup of claim 1 or 2, having a metering hole within the inner cup and a swellable material located in the outer cup below the metering hole.

7. A method of testing a liquid sample for at least one analyte using the specimen cup of claim 1.

8. A method of testing a liquid sample for at least one analyte using the specimen cup of claim 6.