WO2020153901A1

WO2020153901A1 - A microfluidic lateral flow disposable test kit

Info

Publication number: WO2020153901A1
Application number: PCT/SG2019/050038
Authority: WO
Inventors: Lye Hock Sim
Original assignee: Cell Id Pte Ltd
Priority date: 2019-01-23
Filing date: 2019-01-23
Publication date: 2020-07-30

Abstract

A microfluidic lateral flow disposable test kit comprising: a base carrier having a sample collection portion comprising a depression provided in the base carrier; a sealing sheet having a sample collection opening, the sample collection opening being sealed before use of the test kit; a number of lateral flow test strips sealed between the base carrier and the sealing sheet; and a top sheet layered over the sealing sheet before use of the test kit to keep the sample collection opening sealed, the top sheet being at least partially detachable from the sealing sheet to open the sample collection opening and expose the sample collection portion for receiving a fluid sample therein during use of the test kit, wherein the base carrier further comprises a number of channels in fluid communication with the sample collection portion, each of the number of lateral flow test strips being provided in each of the number of channels, such that a single sample of a fluid when placed in the sample collection portion flows into the number of lateral flow test strips provided in the number of channels.

Description

A MICROFLUIDIC LATERAL FLOW DISPOSABLE TEST KIT

FIELD OF THE INVENTION

This invention relates to a test kit, and in particular, to a microfluidic lateral flow disposable test kit for conducting an immunoassay on a fluid sample.

BACKGROUND OF THE INVENTION

Disposable test kits such as home pregnancy test kits or laboratory test kits using bodily fluids such as urine or blood to detect or diagnose disease or other medical conditions are in common use throughout the world. Such test kits typically comprise a test strip sealed in a moisture barrier packaging before use in order to keep the test strip stable and protected during storage and transportation, to extend the shelf life of the test kit. The moisture barrier packaging typically comprises a foil bag or pouch. The test strip may additionally be encased in a plastic cassette for easier handling by the end user, in which case the test strip and cassette are both sealed in the moisture barrier bag before use. Where the test kit includes a cassette, the cassette is typically provided with an open reaction window that allows one or more test lines on the test strip to be viewed during use.

As disposable test kits are used in great quantities internationally, there is a need to provide them at as low a cost and as conveniently as possible, particularly in order to benefit those in impoverished circumstances. In epidemic situations, there is also a need to ensure that tests can be safely and effectively performed, and results effectively captured and stored. Furthermore, where multiple immunochromatographic assays need to be performed for each patient, for example, to test for different diseases or blood sugar levels, it is also currently laborious, difficult (if not impossible) and/or unpleasant to patients to have to obtain multiple fluid samples or to obtain a sufficiently large sample that can be divided for use with multiple test kits.

SUMMARY OF INVENTION

According to a first aspect, there is provided a microfluidic lateral flow disposable test kit comprising: a base carrier having a sample collection portion comprising a depression provided in the base carrier; a sealing sheet having a sample collection opening, the sample collection opening being sealed before use of the test kit; a number of lateral flow test strips sealed between the base carrier and the sealing sheet; and a top sheet layered over the sealing sheet before use of the test kit to keep the sample collection opening sealed, the top sheet being at least partially detachable from the sealing sheet to open the sample collection opening and expose the sample collection portion for receiving a fluid sample therein during use of the test kit, wherein the base carrier further comprises a number of channels in fluid communication with the sample collection portion, each of the number of lateral flow test strips being provided in each of the number of channels, such that a single sample of a fluid when placed in the sample collection portion flows into the number of lateral flow test strips provided in the number of channels.

The base carrier may comprise a plurality of lateral flow tests provided in a plurality of channels to allow a plurality of lateral flow immunochromatographic assays to be simultaneously performed.

Each of the number of lateral flow test strips may be configured to perform a different immunochromatographic assay.

The base carrier may further comprise a concavity in fluid communication with a downstream end of each of the number of channels, and a wicking pad may be provided in the concavity to collect fluid that may have passed through the number of lateral flow tests strips.

The base carrier may further comprise at least one conduit connecting an upstream end of each of the number of channels with the sample collection portion.

The at least one conduit may have a shallower depth than the number of channels to facilitate flow of the fluid from the sample collection portion through the at least one conduit into the number of channels via capillary action.

The at least one conduit may have a sloped bottom, the at least one conduit having a same depth as the sample collection portion where the at least one conduit joins the sample collection portion, the at least one conduit increasing in depth to a maximum depth where the at least one conduit joins the number of channels.

The sample collection portion, the at least one conduit, the number of channels and the concavity may be integral with the base carrier. The base carrier may comprise a portion of an embossed carrier tape.

The sample collection opening may be sealed by a cover before use of the test kit, the cover being attached to the top sheet such that at least partially detaching the top sheet from the sealing sheet detaches the cover from the sealing sheet to open the sample collection opening.

The sealing sheet may further comprise a number of transparent portions configured as reaction windows and the number of lateral flow test strips may each have at least one test line viewable through the reaction windows.

The top sheet may further comprise a number of transparent portions aligned with the reaction windows of the sealing sheet.

The sealing sheet and the top sheet may each comprise a moisture barrier polymeric film.

The test kit may require no additional moisture barrier packaging to keep the number of lateral flow test strips stable during storage of the test kit before use.

The test kit may comprise at least one quick response code provided thereon for storing information therein.

The top sheet may be configured to be re-attachable to the sealing sheet to cover the sample collection opening after use of the test kit to prevent fluid in the sample collection portion from coming into contact with another object.

The base carrier may comprise a plurality of channels and a corresponding plurality of lateral flow test strips each configured to detect a different blood glucose level.

BRIEF DESCRIPTION OF FIGURES

In order that the invention may be fully understood and readily put into practical effect there shall now be described by way of non-limitative example only exemplary embodiments of the present invention, the description being with reference to the accompanying illustrative drawings. FIG. 1 is an exploded assembly top view of a first exemplary embodiment of a microfluidic lateral flow disposable test kit.

FIG. 2 is a schematic illustration of a side view of a base carrier of the test kit of FIG. 1.

FIG. 3 is a top view of a base carrier of a second exemplary embodiment of a microfluidic lateral flow disposable test kit.

DETAILED DESCRIPTION

Exemplary embodiments of the microfluidic lateral flow disposable test kit 10 will be described below with reference to FIGS. 1 to 3. The same reference numerals are used throughout the figures to refer to the same or similar parts.

As shown in FIG. 1 , the microfluidic lateral flow disposable test kit 10 comprises a base carrier 20 having a sample collection portion 21 , a sealing sheet 30 having a sample collection opening 31 provided over the sample collection portion 21 , a number of lateral flow test strips 40 sealed between the base carrier 20 and the sealing sheet 30 before use of the test kit 10, and a top sheet 50. The sample collection opening 31 is sealed before use of the test kit 10. The sealing sheet 30 is provided between the top sheet 50 and the base carrier 20. The top sheet 50 is configured to be attached to the sealing sheet 30 before use of the test kit 10 to keep the sample collection opening 31 sealed. The base carrier 20, sealing sheet 30 and top sheet 50 are preferably rectilinear in shape and of the same size so that the microfluidic lateral flow disposable test kit 10 is a simple, almost flat rectangular package.

The top sheet 50 is further configured to be at least partially detached from the sealing sheet

30 to open the sample collection opening 31 during use of the test kit 10. This may be achieved by layering the top sheet 50 over the sealing sheet 30 and providing the top sheet 50 with at least one appropriately located die cut line 57 (e.g. on at least one side of the sample collection opening 31 ) to allow a detachable portion 51 of the top sheet 50 to be at least partially peeled away from the sealing sheet 30. When the sample collection opening

31 has been opened, a sample collection portion 21 provided as a depression 21 in the base carrier 20 is exposed through the sample collection opening 31 of the sealing sheet 30 and can then receive a liquid sample therein. The sample collection portion 21 may have a depth ranging from about 0.5mm to about 5mm.

The sample collection opening 31 is preferably sealed by a cover 38 before use of the test kit 10, as shown in FIG. 1 . The cover 38 is preferably integral with or part of the sealing sheet 30. Before use of the test kit 10, the cover 38 is already attached to an underside of the detachable portion 51 of the top sheet 50 such that at least partially detaching the top sheet 50 from the sealing sheet 30 detaches the cover 38 from the sealing sheet 30 to open the sample collection opening 31. The cover 38 may be defined by a die cut line to facilitate its detachment from the sealing sheet 30 when the detachable portion 51 of the top sheet 50 is detached from the sealing sheet 30.

The detachable portion 51 of the top sheet 50 is preferably configured to be re-attachable to the sealing sheet 30 to cover the sample collection opening 31 after use of the test kit 10, in order to prevent the fluid in the sample collection portion 21 from coming into contact with another object. This is a safety or hygiene feature to minimize or prevent human handlers of the used test kit 10 from being contaminated by contaminants in the fluid, and to minimize or prevent cross contamination with other used test kits 10.

Each of the number of lateral flow test strips 40 preferably has at least one test line 43, and preferably also at least one control line 47. Although the test lines 43 and control lines 47 have been indicated by dotted lines in FIG. 1 , it will be appreciated that the test lines 43 and control lines 47 will not be visible before use of the test kit 10. The control lines 47 will only appear during use of the test kit 10 if the test kit 10 is a valid one, and the test line 43 on each of the number of lateral flow test strips 40 will only appear during use if an analyte that each of the number of lateral flow test strips 40 is configured to test for is present in the fluid. Preferably, the sealing sheet 30 is provided with a number of transparent portions configured as reaction windows 33 aligned over the test line 43 and the control line 47 of each of the number of lateral flow test strips 40, so that the test lines 43 and control lines 47 can be seen through the reaction windows 33.

As the top sheet 50 is layered over the sealing sheet 30, the top sheet 50 preferably also comprises a number of transparent portions 53 aligned with the number of reaction windows 33 of the sealing sheet 30 to allow the test lines 43 and the control lines 47 of the number of lateral flow test strips 40 to be seen through both the sealing sheet 30 and the top sheet 50. In an alternative embodiment, the top sheet 50 may be layered only partially over the sealing sheet 30 without being layered over the reaction window 33, in which case no transparent portion needs to be provided in the top sheet 50.

As shown in FIGS. 1 and 2, the base carrier 20 further comprises a number of channels 23 in fluid communication with the sample collection portion 21 . The number of channels 23 may each have a depth ranging from about 0.5mm to about 2mm, and a width ranging from about 2mm to about 5mm. Each of the number of lateral flow test strips 40 of the test kit 10 is provided in each of the number of channels 23. In this way, when a single sample of a fluid is placed in the sample collection portion 21 , the fluid flows into the number of channels 23 and into the number of lateral flow test strips 40 in the number of channels 23.

In the test kit 10, the number of channels 23 may be one or more, and the number of lateral flow test strips 40 may be one or more. For example, in some embodiments, as shown in FIGS. 1 and 3, the test kit 10 may comprise a plurality (i.e. two or more) lateral flow test strips 40 provided in a corresponding plurality of channels 23, wherein each of the plurality of lateral flow test strips is configured to perform a different immunochromatographic assay. In this way, the test kit 10 can perform multiple assays simultaneously using a single sample fluid and single placement of the sample into the test it 10. Preferably, the plurality of channels 23 and lateral flow test strips 40 are provided in parallel to each other. Alternatively (not shown), the test kit 10 may comprise only one lateral flow test strip 40 provided in one channel 23 so that the test kit 10 performs only one assay.

The base carrier 20 may further comprise a concavity 29 in fluid communication with a downstream end of each of the number of channels 23. A wicking pad 49 may be provided in the concavity 29 to collect fluid that has passed through the number of lateral flow tests strips 40 provided in the number of channels 23. The concavity 29 preferably has a same depth as each of the number of channels 23.

In a first exemplary embodiment as shown in FIGS. 1 and 2, an upstream end of each of the number of channels 23 may be connected to the sample collection portion 21 via a conduit 24. The conduit 24 preferably has a shallower depth than the number of channels 23 to facilitate flow of the fluid from the sample collection portion 21 through the conduit 24 into the number of channels 23 via capillary action. For example, the conduit 24 may have length ranging from 2mm to 10mm and a depth ranging from about 0.5mm to about 2mm. Further preferably, the conduit 24 may have a sloped bottom (as can be seen in FIG. 2) such that the conduit 24 has a same depth as the sample collection portion 21 where the conduits 24 join the sample collection portion 21 , and the conduit 24 increases in depth to a maximum depth of 3mm where the conduit 24 joins the number of channels 23. It should be noted that FIG. 2 is not drawn to scale but is exaggerated in depth for ease of visualization. In a second exemplary embodiment as shown in FIG. 3, an upstream end of each of the number of channels 23 may be connected to the sample collection portion 21 via a corresponding number of conduits 24. The conduits 24 preferably have a shallower depth than the number of channels 23 to facilitate flow of the fluid from the sample collection portion 21 through the conduits 24 into the number of channels 23 via capillary action. Further preferably, the conduits 24 may have a sloped bottom such that the conduits 24 have a same depth as the sample collection portion 21 where the conduits 24 join the sample collection portion 21 , and increase in depth to a maximum depth where the conduits 24 join the number of channels 23.

The sample collection portion 21 , number of channels 23, at least one conduit 24 and concavity 29 are preferably integral with the base carrier 20. This may be achieved by the base carrier 20 being a single part that may be made by known processes such as embossing, compression moulding, injection moulding, or vacuum forming. In a preferred embodiment, the base carrier 20 may comprise a portion of an embossed carrier tape. Carrier tape is traditionally used in the electronics packaging industry to package and protect electronic components, integrated circuits, and other devices from physical and electrostatic discharge damage during shipping and storage. In this way, the base carrier 20 may be quickly and cost effectively mass-produced by embossing multiple copies of the sample collection portion 21 , the at least one conduit 24, the number of channels 23 and the concavity 29 in a continuous length of carrier tape followed by appropriate cutting of the carrier tape into portions that each form the base carrier 20.

For all embodiments, the sealing sheet 30 and top sheet 50 each preferably comprise a moisture barrier polymeric film so that number of test strips 40 are kept well sealed between the base carrier 20 and sealing sheet 30 before use of the test kit 10. The base carrier 20 is made of a bio-stable polymeric plastic such as polycarbonate, polyethyl terephthalate, polypropylene and so on. In this way, the test kit 10 requires no additional moisture barrier packaging to keep the number of test strips 40 stable during storage and transportation of the test kit 10 before use. This also greatly reduces the size of the test kit 10 and the space it takes up, which would have a significant impact particularly when test kits need to be moved in areas with poor transportation networks or accessibility. For example, a single healthcare worker going on foot to a remote location will be able to take with him or her a significantly greater number of the test kits 10 of the present invention in a single hand-carry bag or case or even clothing pocket compared to existing test kits comprising plastic cassettes in foil bags that would be significantly more bulky to carry. Doing away with the need for an additional moisture barrier foil bag and plastic cassette also significantly reduces the cost of the present test kit 10, since each foil bag and each plastic cassette contributes to the total cost of each traditionally available test kit.

In addition, for all embodiments, the microfluidic lateral flow disposable test kit 10 of the present invention is preferably provided with at least one quick response (QR) code 80 on the test kit 10, more preferably located on the top sheet 50 for easy access. The at least one QR code 80 allows information such as manufacturing date, expiry date and source information of the at least one test strip 40 and the test kit 10 itself to be stored and retrieved, as well as allowing the test kit 10 to be associated or tagged with a single specific source of the fluid sample. The specific source may be a patient or any other fluid sample supply, depending on the usage application of the test kit 10. The QR code is preferably located on a part 58 of the top sheet 50 where the part 58 of the top sheet 50 is never detached from the sealing sheet 30. In this way, the quick response code 80 is never separated from the test strip 40 in the test kit 10 after use, and each test strip 40 can be correctly traced to its specific fluid sample source. For example, where the test kit 10 is used to diagnose presence of diseases in individuals of a large population of patients, having the quick response code 80 on each test kit 10 allows each test kit 10 to be indelibly and indubitably associated with only one specific patient, thereby minimizing or preventing mix-ups in test results from occurring.

As shown in FIG. 1 , the test kit 10 may be configured as an FlbAlc test kit 10 to measure the amount of blood sugar (glucose) attached to haemoglobin in a blood sample comprising a single drop of blood. The test kit 10 is provided with four lateral flow test strips 40 that each detects a different blood glucose level. The first test strip is configured to show a visible test line 43 when glucose level in the blood sample is at least 5.5% and less than 6.5%. The second test strip is configured to show a visible test line 43 when glucose level in the blood sample is at least 6.5 % and less than 7.5%. The third test strip is configured to show a visible test line 43 when glucose level in the blood sample is at least 7.5% and less than 8.5%. The fourth test strip is configured to show a visible test line 43 when glucose level in the blood sample is at least 8.5%. For example, if glucose level in the blood sample is 5.8 %, the first test strip indicated by a‘5.5%’ marking on the top sheet 50 will show a visible test line 43, while the test lines 43 of the second test strip, the third test strip and the fourth test strip (these test strips being indicated by‘6.5%’, 7.5%’ and‘8.5%’ markings on the top sheet 50 respectively) will remain invisible. In this way, it will be known from using the test kit 10 that glucose level in the blood sample is greater than 5.5% but below 6.5%. The HbA1c test kit 10 thus allows a patient’s blood glucose level to be quantified as being within a specific percentage band.

The present invention thus provides a low cost, low bulk, microfluidic lateral flow disposable test kit 10 that can be easily associated with a specific fluid sample source or patient and that can be configured to simultaneously perform multiple immunochromatographic assays on a single fluid sample that has a volume of only a single drop of liquid.

Whilst there has been described in the foregoing description exemplary embodiments of the present invention, it will be understood by those skilled in the technology concerned that many variations in details of design, construction and/or operation may be made without departing from the present invention. For example, while it has been described that the sealing sheet and top sheet are preferably made of a moisture barrier polymeric film, they may alternatively be made of appropriately laminated paper with sufficient moisture barrier properties required for stable storage of the test strips therein. It is further envisaged that in various embodiments of the test kit, the top sheet may or may not be layered over all of the sealing sheet so long as it is layered over the sample collection opening to keep the sample collection opening sealed before use of the test kit. While the number of lateral flow test strips and number of channels in the base carrier have been depicted in the figures as being parallel to each other, in other embodiments, the number of lateral flow test strips and number of channels in the base carrier may be provided as radiating from a centrally provided sample collection portion in the base carrier.

Claims

1. A microfluidic lateral flow disposable test kit comprising:

a base carrier having a sample collection portion comprising a depression provided in the base carrier;

a sealing sheet having a sample collection opening, the sample collection opening being sealed before use of the test kit;

a number of lateral flow test strips sealed between the base carrier and the sealing sheet; and

a top sheet layered over the sealing sheet before use of the test kit to keep the sample collection opening sealed, the top sheet being at least partially detachable from the sealing sheet to open the sample collection opening and expose the sample collection portion for receiving a fluid sample therein during use of the test kit,

wherein the base carrier further comprises a number of channels in fluid communication with the sample collection portion, each of the number of lateral flow test strips being provided in each of the number of channels, such that a single sample of a fluid when placed in the sample collection portion flows into the number of lateral flow test strips provided in the number of channels and into the number of lateral flow tests provided in the number of channels.

2. The microfluidic lateral flow disposable test kit of claim 1 , wherein the base carrier comprises a plurality of lateral flow tests provided in a plurality of channels to allow a plurality of lateral flow immunochromatographic assays to be simultaneously performed.

3. The microfluidic lateral flow disposable test kit of claim 2, wherein each of the number of lateral flow test strips is configured to perform a different immunochromatographic assay.

4. The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the base carrier further comprises a concavity in fluid communication with a downstream end of each of the number of channels, and wherein a wicking pad is provided in the concavity to collect fluid that has passed through the number of lateral flow tests strips.

5. The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the base carrier further comprises at least one conduit connecting an upstream end of each of the number of channels with the sample collection portion.

6. The microfluidic lateral flow disposable test kit of claim 5, wherein the at least one conduit has a shallower depth than the number of channels to facilitate flow of the fluid from the sample collection portion through the at least one conduit into the number of channels via capillary action.

7. The microfluidic lateral flow disposable test kit of claim 6, wherein the at least one conduit has a sloped bottom, the at least one conduit having a same depth as the sample collection portion where the at least one conduit joins the sample collection portion 21 , the at least one conduit increasing in depth to a maximum depth where the at least one conduit joins the number of channels.

8. The microfluidic lateral flow disposable test kit of any one of claims 5 to 7, wherein the sample collection portion, the at least one conduit, the number of channels and the concavity are integral with the base carrier.

9. The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the base carrier comprises a portion of an embossed carrier tape.

10. The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the sample collection opening is sealed by a cover before use of the test kit, the cover being attached to the top sheet such that at least partially detaching the top sheet from the sealing sheet detaches the cover from the sealing sheet to open the sample collection opening.

1 1 . The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the sealing sheet further comprises a number of transparent portions configured as reaction windows and wherein the number of lateral flow test strips each have at least one test line viewable through the reaction windows.

12. The microfluidic lateral flow disposable test kit of claim 1 1 , wherein the top sheet further comprises a number of transparent portions aligned with the reaction windows of the sealing sheet.

13. The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the sealing sheet and the top sheet each comprise a moisture barrier polymeric film.

14. The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the test kit requires no additional moisture barrier packaging to keep the number of lateral flow test strips stable during storage of the test kit before use.

15. The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the test kit comprises at least one quick response code provided thereon for storing information therein.

16. The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the top sheet is configured to be re-attachable to the sealing sheet to cover the sample collection opening after use of the test kit to prevent fluid in the sample collection portion from coming into contact with another object.

17. The microfluidic lateral flow disposable test kit of any one of the preceding claims, wherein the base carrier comprises a plurality of channels and a corresponding plurality of lateral flow test strips each configured to detect a different blood glucose level.