GB2430032A

GB2430032A - Assay device

Info

Publication number: GB2430032A
Application number: GB0617951A
Authority: GB
Inventors: Nicholas Long; Andrew Ledgeway
Original assignee: Inverness Medical Switzerland GmbH
Current assignee: Alere Switzerland GmbH
Priority date: 2005-09-13
Filing date: 2006-09-12
Publication date: 2007-03-14
Anticipated expiration: 2026-09-12
Also published as: GB2430032B; GB0617951D0; GB0518652D0; DE102006043025A1

Abstract

The invention provides an assay device 1, for detecting an analyte in a sample, comprising a sample receiving chamber 3, a fluid-containing reservoir 4, a releasing means 6 for releasing fluid from the fluid reservoir, and a means for detecting the analyte in the sample 7. Insertion of the sample into the assay device causes the releasing means to release fluid from the fluid reservoir, whereupon the fluid contacts the sample before passing along the device to enter the detecting means 7 via conduit 10. The assay device provides a simple one-step diagnostic test for medical conditions, which can be carried out by a patient. The invention also provides an assay kit comprising an assay device and a sampling device. The invention also provides a sampling device for taking a sample from a subject, which comprises a shaft having at least one radially extending projection (24) forming a substantially continuous peripheral surface around the shaft.

Description

Device The present invention relates to an assay device for detecting the

presence of an analyte in a sample, to an assay kit comprising the assay device, and to devices for obtaining a sample from a subject. In particular but not exclusively, the invention relates to assay devices and kits for detecting the presence of an analyte in a sample taken from a bodily orifice, and to sampling devices for taking a sample from a bodily orifice.

A variety of methods for detecting the presence of an analyte in a sample are known.

Although many such methods involve successive stages of analysis which are carried out separately, and often in the laboratory, assay devices have been developed which conduct the entire analytical procedure within a single device. Such devices provide a convenient method of producing a definitive result in a fast and simple manner, without requiring the user to understand or undertake the technical steps of the assay.

Many clinical diagnostic tests require the detection of a particular analyte within the human body. The taking of a bodily sample from a patient can cause significant physical and psychological discomfort to the patient, particularly when such samples are taken directly by a healthcare professional. There is therefore a need for diagnostic assay devices, kits and sampling devices which can be operated by a patient without the need to involve a healthcare professional.

Bacterial Vaginosis (BV) is a condition in women where the normal balance of bacteria (Lactobacilli) in the vagina is disrupted and replaced by an overgrowth of certain bacteria such as Gardnerella vaginalis. It is sometimes accompanied by discharge, odour, pain, itching, or burning. In most cases, BY causes no complications, but there are some serious risks from BY such as an increase in susceptibility to H1V infection as well as increase in the chance that an HIV-infected woman can transmit HIV. Having BV has been associated with an increase in the development of pelvic inflammatory disease (PID) following surgical procedures such as a hysterectomy or an abortion. Having BY while pregnant may put a woman at 472161v1 increased risk for some complications of pregnancy. BV can increase a woman's susceptibility to other sexually transmitted diseases (STDs), such as chiamydia and gonorrhoea.

A number of diagnostic tests and methods exist for the diagnosis of BV including vaginal fluid tests, a litmus paper test of vaginal acidity, and the microscopic examination of vaginal discharge to identify the presence of bacteria associated with By.

Candida albicans is normally found in small amounts in the vagina, the mouth, the digestive tract, and on the skin without causing disease or symptoms (approximately 25% of women without disease symptoms have this organism present). Disease symptoms in the vagina appear when the balance between the normal micro organisms present in the vagina is lost, and the Candida albicans population becomes larger in relation to the other micro organism populations normally present in the vagina. This may result in condition known as candidiasis moniliasis, which is commonly known as a yeast infection. Yeast infection may follow a course of antibiotics (particularly tetracycline), since antibiotics can change the normal balance between organisms in the vagina by suppressing the growth of protective bacteria that normally have an antifungal effect. Infection is common among women who use oestrogen-containing birth control pills and among women who are pregnant. This is due to the increased level of oestrogen in the body. The increased hormone level causes changes in the vaginal environment that make it optimal for fungal growth and nourishment.

Most candida infections can be treated at home. Treatment methods include topical administration of antifimgal drugs such as clotrimazole, miconazole, nystatin, tioconazole, or oral administration of drugs such as fluconazole and amphotericin B. More serious infections may require admittance to hospital.

Diagnostic methods for BV and candida infection usually involve the insertion of a swab into the vagina by a healthcare professional. The material present on the swab is 472161v1 subsequently tested in the laboratory for the presence of the organisms associated with these conditions.

In contrast to the available diagnostic methods for BV and candida infection, the applicant has devised an assay device which provides a simple one-step diagnostic test for conditions such as BV and candida, which can be conducted by the patient without the need to visit a healthcare professional. In addition, the applicant has devised a sampling device for taking a sample from a bodily orifice, which provides a more comfortable method of taking a sample, and which can be operated by the patient.

In a first aspect, the present invention provides an assay device comprising: a sample receiving chamber with an opening adapted to receive a sample; a reservoir containing fluid; releasing means for releasing the fluid from the reservoir; and means for detecting the presence of an analyte in the sample; wherein insertion of the sample into the sample receiving chamber causes the releasing means to release the fluid contained in the reservoir, whereupon the fluid contacts the sample and moves from the sample to the means for detecting the presence of an analyte in the sample.

The components of the assay device may be encased by a single housing. The components of the assay device of the invention may be arranged in any position relative to one another, provided that, upon insertion of the sample into the sample receiving chamber, the releasing means releases the fluid contained in the reservoir, whereupon the fluid contacts the sample and moves from the sample to the means for detecting the presence of an analyte in the sample (the detecting means).

In one embodiment, the assay device is arranged so that the sample receiving chamber is adapted to receive a sample at a proximal end of the chamber, the reservoir is positioned at the distal end of the chamber, the releasing means is positioned intermediate the sample (when received) and the reservoir, and the detecting means is 472161v1 positioned at the proximal end of the chamber. In this arrangement, the sample is inserted into the chamber until the sample contacts the releasing means and causes the releasing means to release the fluid from the reservoir. The fluid contacts the sample, moving towards the proximal end of the chamber whilst in fluid contact with the sample until the fluid reaches the detecting means. Alternatively, the releasing means may be positioned at the proximal end of the chamber and be triggered to release the fluid from the reservoir when the sample reaches the distal end of the chamber.

In an alternative embodiment, the reservoir is positioned at the proximal end of the chamber and the detecting means is positioned at the distal end of the chamber, in an arrangement such that the insertion of the sample into the chamber beyond the reservoir causes the releasing means to release the fluid from the reservoir. In this embodiment, the releasing means may be positioned at the proximal or distal end of the chamber.

The sample may be carried by a sampling device. The sampling device carrying the sample preferably obstructs the opening of the sample receiving chamber when the sample is inserted into the sample receiving chamber, such that the sample receiving chamber becomes fluid-tight. Thus, when the fluid is released from the reservoir, the fluid cannot escape from the chamber opening.

A sampling device used to carry the sample into the assay device of the invention can be any device capable of being inserted into the sample receiving chamber. In particular, the sampling device may be adapted to take a sample from a subject, which allows the direct transfer of the sample from the subject to the assay device. The sampling device may be elongate, with a handle portion to be held by the user, and a head portion on which the sample is collected. The sampling device may comprise a non-porous head portion, or a substantially non-porous head portion (i.e. a head portion which is 50%, 60%, 70%, 80%, 90%, 95%, 98%, 99% or 99.9% non-porous).

Alternatively, the head portion may comprise a porous head portion. The head portion may have one or more fluid pathways provided on its outer surface along which fluid from the fluid reservoir is able to flow. The fluid pathway may be a 472161v1 channel, for example a helical shaped channel or a longitudinal channel. A plurality of fluid channels may be provided. Insertion of the sampling device into the sample receiving chamber may cause the releasing means to release fluid contained in the reservoir, whereafter the fluid contacts at least a portion of the sampling device. Fluid is thereafter able to flow to the means for detecting the presence of an analyte in the sample.

The sampling device may be formed from a plastic, such as a thermoplastic. The sampling device may be of an adequate rigidity to withstand insertion into a bodily orifice and/or into the sampling device.

Sampling devices used by healthcare professionals to take a sample from the bodily orifice of a patient (often referred to as swabs) may contain radiating fibres or bristles extending from the head of the device, which are designed to trap fluids, residues, or other bodily matter. Such sampling devices may be used in conjunction with the assay device of the invention.

In a preliminary operating step of the assay device of the invention, the sample is inserted into the sample receiving chamber. The sample receiving chamber may be constructed of any fluid impervious material.

The reservoir of the assay device of the invention may be any container which is capable of retaining fluid, and which may be caused to release the fluid by a releasing means. In one embodiment, the reservoir comprises a puncturable material, and the releasing means comprises a puncturing device which punctures the material to release the fluid held in the reservoir. Suitable materials from which the reservoir can be constructed include metals, metal alloys, plastics, polymers, or any other fluid impervious materials. The reservoir may comprise a particular region with which the releasing means interacts to release the fluid. For example, the reservoir may comprise a solid container with a fluid-tight seal positioned across the opening of the container. The releasing means may therefore comprise an instrument which is capable of puncturing the seal on the reservoir.

472161v1 The releasing means by which fluid is released from the reservoir may be any means known to the person skilled in the art which causes the fluid to be released from the reservoir. The releasing means may comprise a mechanical device which is triggered by physical contact with the sample or a sampling device to release the fluid from the reservoir. For example, the releasing means may be a puncturing device capable of puncturing the reservoir to release the fluid. Alternatively, the releasing means may comprise an electronic device which is triggered upon detection of the sample or a sampling device to effect the release of fluid from the reservoir. Many releasing means suitable for use in the assay device of the invention are known to the person skilled in the art.

In one embodiment of the assay device of the invention, the releasing means comprises a pin with a head portion and an elongate pointed shaft extending from the head portion. The pin may be arranged so that a sampling device carrying the sample inserted into the sample receiving chamber abuts the head portion of the pin and exerts a force on the pin which urges the pin to move so that the pointed shaft of the pin punctures the reservoir.

The fluid held in the reservoir is preferably a liquid. In one embodiment of the invention, the fluid is a buffer solution which is capable of maintaining the structural and/or functional integrity of the analyte of interest which may be present in the sample. The fluid may be any fluid which is capable of mobilising the analyte of interest, such that the analyte of interest is transported to the detecting means in solution or suspension.

The fluid may comprise reagents which are molecular components of the means for detecting the presence of an analyte in the sample. Such components may interact with (and possibly bind to) the analyte of interest in the sample, if present, before the fluid reaches the detecting means.

472161v1 The fluid, when released from the reservoir, may be urged to move from the reservoir to the sample and subsequently to the detecting means by any suitable means. For example, the fluid may be held in the reservoir under high pressure (which may be any pressure greater than that in the sample receiving chamber) so that the release of fluid from the reservoir causes the fluid to move from the container into the sample receiving chamber. Alternatively, the fluid may be urged to move by the forces of gravity. For example, the assay device may be designed so that the fluid has a greater gravitational potential when held in the reservoir than the sample when present in the sample receiving chamber, so that the fluid, when released from the reservoir, is urged by gravitational force to move to the sample and subsequently to the detecting means.

Alternatively, the reservoir may comprise a fluid pump, which, when activated by the releasing means, pumps the fluid from the reservoir to the sample, and subsequently to the detecting means. The reservoir may comprise collapsible and/or compressible walls. The collapsible and/or compressible walls may be concertinaed or collapsed by the releasing means, such that the action of force on the reservoir causes a reduction in its internal volume resulting in ejection of fluid from the reservoir. Other means of ensuring that the fluid is urged to move from the reservoir to the sample and subsequently to the detecting means will be apparent to the person skilled in the art.

When the fluid is released from the reservoir into the sample receiving chamber, the fluid contacts the sample prior to reaching the detecting means. The assay device of the invention may be adapted in various ways to ensure (or to improve or increase) contact between the fluid and the sample. For example, the dimensions of the sample receiving chamber and a sampling device on which the sample is presented may be arranged so that the volume of the sample receiving chamber is significantly reduced when the sampling device is inserted into the chamber, whilst retaining a maximal surface area of the sampling device (with the sample carried thereon), so that a high proportion of the fluid directly contacts the sample when moving from the reservoir to the detecting means.

In one embodiment, the inner surface of the sample receiving chamber may have a protruding thread running helically along the length of the sample receiving chamber.

472161v1 When the sample is carried on the outer surface of a sampling device which is a cylindrical rod with a smooth outer surface, the chamber may be adapted to receive the sampling device in such a way that the outer edges of the protruding helical thread on the inner surface of the chamber contact the surface of the sampling device. In this embodiment, when the fluid is released from the reservoir, the fluid moves through the helical channel formed by the helical thread and the outer surface of the sampling device, ensuring that the fluid is held in fluid contact with the exposed surface of the sampling device.

Alternatively, the sample receiving chamber may have a smooth inner surface, and a sampling device on which the sample is carried may be specifically adapted to ensure or improve the contact between the fluid and the sample. For example, the sampling device may comprise a shaft with a protruding thread running helically along the length of the shaft, wherein the sample is carried on the surface of the protruding thread and shaft. When the sampling device is inserted into the sample receiving chamber, the inner surface of the sample receiving chamber may contact the outermost edges of the protruding thread, thereby forming a helical channel through which the fluid can move.

On contact between the sample and the fluid, an analyte of interest may be mobilised in the fluid, and transported in solution or suspension to the detecting means.

The detecting means can be positioned anywhere within the assay device, provided that the fluid, when released from the reservoir, contacts the sample prior to contacting the detecting means.

In the assay device of the invention, the detecting means may be positioned in a separate chamber within the assay device, and the fluid, having contacted the sample, may be conveyed to the detecting means via a conduit positioned in the sample receiving chamber. In one embodiment, when the reservoir is positioned at the distal end of the chamber, a fluid conduit is positioned at the proximal end of the chamber, 472161v1 which conveys the fluid to a detecting means positioned in a separate chamber within the assay device.

The detecting means in the assay device of the invention may be any means suitable for determining the presence or absence of a particular analyte in a sample, or for measuring the amount of the analyte in a sample.

The detecting means may comprise a binding agent capable of binding specifically to the analyte of interest to form a specific binding pair. The formation of a specific binding pair may then be detected by any suitable means. Examples of specific binding pairs, wherein the analyte of interest may be either one of the agents in the specific binding pair, include an antibody and antigen where the antigen may be a peptide sequence, complementary nucleotide or peptide sequences, polymeric acids and bases, dyes and protein binders, peptides and specific protein binders, enzymes and cofactors, enzymes and substrates, and effector and receptor molecules, where the term receptor refers to any compound or composition capable of recognising a particular or polar orientation of a molecule, namely an epitopic or determinant site.

Reference to an antibody includes but is not limited to, polyclonal, monoclonal, bispecific, humanised and chimeric antibodies, single chain antibodies, Fab fragments and F(ab')2 fragments, fragments produced by a Fab expression library, anti-idiotypic (anti-Id) antibodies, and epitope-binding fragments of any of the above. Portions of antibodies include Fv and Fv' portions. Fv portions can be modified to produce a synthetic construct known as a single chain Fv (scFv) molecule. This includes a peptide linker covalently joining Vh and V1 regions, which contributes to the stability of the molecule. Antibodies can be naturally-occurring antibodies, e.g., monoclonal antibodies obtained by the method of Koehier and Milstein and polyclonal antibodies obtained, for example, by injection of an antigen into an animal. Antibodies can also be partially or fully humanised. Other synthetic constructs that can be used include Complementarity Determining Regions (CDR) peptides. These are synthetic peptides comprising antigen- binding determinants. Peptide mimetics may also be used. These 4721 61v1 molecules are usually conformationally restricted organic rings that mimic the structure of a CDR loop and that include antigen-interactive side chains.

The binding agent may be immobilised on a solid substrate or may be present in a solution. The binding agent may be attached to a solid substrate by any means known to one of skill in the art. The binding agent may be attached directly, or may be attached to a supporting molecule which is itself immobilised on the solid substrate.

By way of example, suitable solid substrates for use in the assay device of the invention may include filter paper, or nitrocellulose paper.

Where the analyte of interest is an enzyme, the detecting means may comprise the provision of a substrate for that particular enzyme, wherein the reaction of the enzyme (if present in the sample) with the substrate can be detected. For example, the reaction between the target enzyme and substrate may result in the production of a colour change, which can be visually detected by the operator of the assay device.

When the assay device of the invention is used for the detection of bacterial vaginosis, the detecting means may be a test for bacterial sialidase. The clinical examination and Gram staining of the bacteria present in a sample taken from a patient is time consuming, and can take several days. Therefore diagnostic assays have been developed based upon the detection of bacterial sialidase. High levels of bacterial sialidase activity are found in the vaginal secretions of women with BY as opposed to those without BY (MacGregor et al (1994) Aim J. Obstet. Gynaecol. 170 1048-1060; Briselden et al (1992) J. Clin. Microbiol. 30 663-666). A rapid assay test for sialidase, as disclosed in WO 0055354, may be used in the assay device of the present invention. This test comprises the provision of a bacterial sialidase substrate, which, when sialidase activity is present, results in a detectable colour change. The preferred substrate is a salt of Sbromo-4-chloro-3-indoyl a-D-N-acetyl neuraminic acid, in particular the cyclohexyl amine(X-a-NANA), which is available from Rose Scientific Ltd., Edmonton, Canada.

472161v1 In one embodiment of the assay device of the invention, the detecting means comprises a rapid assay test. In particular, when the assay device of the invention is used for the detection of candida infection, the detecting means may be based upon a rapid assay test. A number of additional tests may be used for testing for candida infection such as an enzyrnic colorimetric test which tests for the presence of two enzymes, J3-galactosaminidase and L-proline aminopeptidase. Both of these enzymes are produced by C. albicans. However one or both enzymes is absent in other yeast species. Therefore, a test for candida infection may comprise the provision of a substrate for each of these enzymes, wherein each substrate produces a colour change when enzymic activity is present. If the test produces a colour reaction for both of these enzymes, the result is presumptive positive for C. albi cans.

Alternatively the test may be based upon an immunoassay. Suitable immunoassay tests are known to the person skilled in the art.

The assay device may be used to detect the presence of an analyte in a fluid or solid sample. When the sample is a solid sample, it is envisaged that a sampling device presents the solid sample on the exterior surface of the sampling device.

The assay device may be used to detect the presence or absence of more than one analyte in a sample. The detecting means may therefore provide a means for detecting two or more analytes in a sample. In a preferred embodiment, the assay device is used to detect bacterial vaginosis and candida infection in a vaginal fluid sample taken from a female subject.

In a second aspect, the invention provides an assay kit for detecting an analyte in a sample, said assay kit comprising: a sampling device; a sample receiving chamber with an opening adapted to receive the sampling device; a reservoir containing fluid; releasing means for releasing the fluid from the reservoir; and 472161v1 means for detecting the presence of an analyte in the sample; wherein insertion of the sampling device carrying the sample into the sample receiving chamber causes the releasing means to release the fluid contained in the reservoir, whereupon the fluid contacts the sample and moves from the sample to the means for detecting the presence of an analyte in the sample.

The assay kit of the invention may comprise an assay device according to the first aspect of the invention, together with a sampling device. The sampling device may be any device capable of retrieving a physical sample from an object or an animal subject. Preferably, when the sampling device is inserted into the sample receiving chamber, the sampling device forms a fluid impervious contact with the walls of the sample receiving chamber, such that the sample is positioned inside a fluid impervious chamber defined by the walls of the sample receiving chamber and the sampling device.

In a third aspect, the invention provides a sampling device for taking a sample from a subject, comprising a shaft having at least one projection extending radially therefrom, the projection forming a substantially continuous peripheral surface around the shaft.

The substantially continuous peripheral surface allows a sample to be collected from a bodily orifice more efficiently than the known devices which have a plurality of radially extending bristles, which form a discontinuous peripheral surface around the shaft. By "substantially continuous" is meant that the surface is continuous for at least 80, 90 or 95% of its length. In cross-section, the shaft may be any shape, such as square, triangular, hexagonal, etc, although it is preferably circular. Thus, the shaft is preferably cylindrical.

In one embodiment, the or each projection extends helically along the shaft, i.e. forms a thread. Thus, in one embodiment, the sampling device comprises a shaft with a protruding thread running helically around the shaft. When the sampling device is inserted into an assay device of the first aspect, the peripheral surface of the sampling 4721 61v1 device may contact the inner surface of the sample receiving chamber, so that fluid released from the reservoir is channelled through the channel formed by the inner surface of the sample receiving chamber and the outer surface of the helical thread and shaft of the sampling device, the fluid contacting the sample present on the surface of the sampling device.

In another embodiment, the shaft has a plurality of projections extending radially from the shaft, each of which forms a substantially continuous peripheral surface around the shaft. The projections may be circular or any other shape, provided that it allows the collection of a sample from a bodily orifice.

The surface between the shaft and the peripheral surface forms an area on which a sample can be collected. This area forms a surface which preferably extends perpendicularly from the shaft. Material (such as bodily fluid) is typically deposited onto this surface when the sampling device is inserted into, and removed from, a subject. In certain embodiments, this surface is continuous, containing no apertures therein. In certain embodiments, this surface has one or more apertures therein. In those embodiments with a plurality of projections, the apertures in those projections may be arranged to form a helical path around the shaft. When the sampling device is inserted into an assay device of the first aspect, the peripheral surface of the sampling device may contact the inner surface of the sample receiving chamber, so that fluid released from the reservoir is channelled through the apertures in the sampling device, contacting the sample present on the surface of the sampling device.

The dimensions of the sampling device may be adapted to conform to the dimensions of the subject from which the sample is to be taken. Preferably, the sampling device is adapted to retrieve a fluid sample from a bodily orifice of a subject. More preferably, the sampling device is adapted to take a sample from a bodily orifice of a mammalian subject, and more preferably from a bodily orifice of a human subject, such as the mouth, ear, nostril, anus, vagina or urethra.

472161v1 In one embodiment, the sampling device is adapted to take a sample from the vagina of a female human subject.

The sampling device may comprise a handle portion to be held by the user. Upon insertion of the shaft into a bodily orifice, the inner surface of the bodily orifice contacts the peripheral surface of the projection(s) andlor the shaft of the sampling device. The projections increase the likelihood that bodily fluid or tissue is collected by the sampling deviceas it is inserted into and removed from an orifice. Thus, the sampling device can be inserted and withdrawn from an orifice without the need for manipulation of the sampling device (e.g. twisting, scraping) to ensure that a sample of bodily fluid or tissue is retained on the device. This allows a more comfortable sampling method for the user, and allows the user to take the sample themselves.

Preferably, the projections comprise a resilient material such as rubber or latex.

The surfaces of the projections may be smooth, or may be textured to increase the friction between them and the subject from which the sample is taken, thereby increasing the likelihood that sample material will be deposited onto the sampling device. For example, the projections may each comprise additional ridges or grooves to increase the likelihood that sample material will be deposited onto the sampling device.

The projections may be a protruding thread which runs helically along the shaft of the sampling device. Thus, in a preferred embodiment, the sampling device comprises a shaft which is threaded, the thread being a protrusion which runs helically along the shaft.

Alternatively, the protrusions may be a series of discs arranged along the length of the shaft. The discs may be circular, although they can be any other shape, provided that they are suitable for collecting a sample from a bodily orifice. As mentioned above, these discs may have one or more apertures therein.

472161v1 The sampling device of the present invention may further comprise one or more wing portions extending radially therefrom, which prevent the flow of sample fluid onto the handle portion of the sampling device when the sample is being taken. The wing portion(s) may also prevent the sampling device from being inserted entirely into the subject from which the sample is being taken, by virtue of the greater diameter of the wing portions than that of the head portion of the sampling device. Preferably the length by which the or each wing portion extends radially from the sampling device is greater than the radius of the orifice from which a sample is taken. Furthermore, the wing portions may be positioned along the length of the sampling device so that, when the sampling device is inserted into an assay device of the invention, the distance between the proximal end of the sample receiving chamber and the wing portion(s) acts as a guide to the distance between the distal end of the sampling device and the releasing means, in those embodiments where the releasing means is present at the distal end of the sample receiving chamber.

The dimensions of the sampling device may be adapted in accordance with the subject from which a sample is taken.

In a preferred embodiment, the invention provides an assay kit comprising an assay device of the first aspect and a sampling device of the third aspect.

Preferred features of each aspect of the invention are as for each of the other aspects mutatis mutandis. The prior art documents mentioned herein are incorporated by the fullest extent permitted by law.

Particular embodiments of the invention are now described with reference to the drawings. The drawings illustrate exemplary embodiments of the invention only, and should not be viewed as limiting the scope of the invention.

Figure 1(a) - (d) shows one embodiment of an assay kit in accordance with the present invention at successive stages of operation of the assay kit.

472161v1 Figure 2 shows one embodiment of a sampling device in accordance with the present invention.

The assay kit illustrated in Figure 1 comprises an assay device (1) and a sampling device (2). The assay device comprises a sample receiving chamber (3), a reservoir (4) containing fluid (5), a releasing means (6), and a means for detecting the presence of an analyte in a sample (7).

The reservoir (4) is compressible. The fluid contained within the reservoir is buffer solution. The releasing means comprises a pin comprising a head portion (15) and a pointed shaft portion (16), and a stopping portion (17). The detecting means comprises porous lateral flow carrier with molecular components of the detecting means immobilised thereon.

The reservoir comprises a container with a seal (8) covering the container. The sample receiving chamber comprises a protruding thread (9) running helically around the inner surface of the sample receiving chamber. A fluid conduit (10) channels the fluid from the sample receiving chamber to the detecting means. The sampling device comprises a head portion (11), a handle portion (12), and wing portions (13).

In Figure 1 (a), the sampling device (2) is shown being inserted into the sample receiving chamber (3). In Figure 1 (b), the sampling device is inserted further into the sample receiving chamber so that the handle portion of the sampling device forms a fluid-tight connection (14) with the inner surface of the sample receiving chamber, and so that the sampling device abuts the head portion (15) of the releasing means (6).

The peripheral surface of the head portion of the sampling device contacts the outer surface of the protruding helical thread inside the sample receiving chamber, forming a helical channel through which the fluid can pass to reach the detecting means.

Figure 1 (c) shows the sampling device inserted still further into the sample receiving chamber, so that the sampling device applies a mechanical force to the head portion of the releasing means. The pin is urged to move towards the reservoir, guided by the 472161v1 releasing means, so that the pin bursts the seal (8) of the reservoir (4). The pin is prevented from reaching the end of the assay device by the stopping portion (17).

Once the pin has burst the seal on the reservoir, the fluid is released. Further insertion of the sampling device into the assay device compresses the reservoir, forcing the buffer to move from the reservoir into the sample receiving chamber, and along the channel defined by the inner surface of the threaded sample receiving chamber and the outer surface of the sampling device. This arrangement ensures that the buffer is brought into contact with the sample carried on the outer surface of the sampling device.

Figure 1 (d) shows the assay kit after the seal to the reservoir has been burst, the reservoir has been compressed and the fluid has moved from the reservoir to the sample, and subsequently to the detecting means (6) via the fluid conduit (10). The detecting means comprises a porous lateral flow carrier with binding agents specific for the analyte of interest immobilised thereon in a detection zone. Once the fluid now carrying the mobilised analyte of interest (if present), moves along the lateral flow carrier, any analyte of interest will be bound to the immobilised binding agents at the detection zone. The presence of bound analyte of interest at the detection zone can then be visually determined to provide the user with a definitive result.

The sampling device illustrated in Figure 2 comprises a head portion (20), a base portion (21), and a handle portion (22). The head portion comprises a shaft (23) and a protruding helical thread (24) which runs helically along the outer surface of the shaft.

The sampling device further comprises a rounded end (25) which allows more comfortable insertion of the device into a bodily orifice. The base portion (21) has a greater diameter than the diameter of the head portion. The handle portion (22) has a greater diameter than the diameter of the base portion. The handle portion has multiple ridges (26) to improve the user's grip on the handle when taking a sample.

The dimensions of the sampling device illustrated in Figure 2 are described as follows. The total cross section of the head portion is 9. 5mm; the length of the head portion is in the range of 50-100mm; the radial protrusions protrude from the shaft by 472161v1 a distance of 1. 8mm and are 1.0mm thick; and the gap between adjacent radial protrusions is 2.8mm.

472161 vi

Claims

Claims: 1. An assay device for detecting an analyte in a sample, said

assay device comprising: a sample receiving chamber with an opening adapted to receive a sample; a reservoir containing fluid; releasing means capable of releasing the fluid from the reservoir; and means for detecting the presence of an analyte in the sample; wherein insertion of the sample into the sample receiving chamber causes the releasing means to release the fluid contained in the reservoir, whereupon the fluid contacts the sample and moves from the sample to the means for detecting the presence of an analyte in the sample.
2. An assay device according to claim 1, wherein the opening is positioned at a proximal end of the sample receiving chamber and the reservoir is positioned at a distal end of the sample receiving chamber.
3. An assay device according to claim 2, wherein the releasing means is positioned at the distal end of the sample receiving chamber intermediate the sample (when received) and the reservoir.
4. An assay device according to any preceding claim, wherein the detecting means is positioned at the proximal end of the sample receiving chamber.
5. An assay device according to claim 1, wherein the opening is positioned at a proximal end of the sample receiving chamber and the reservoir is positioned at the proximal end of the sample receiving chamber.
6. An assay device according any one of claims 1, 2, 3 or 5, wherein the detecting means is positioned at a distal end of the sample receiving chamber.

4721 61v1
7. An assay device according to claim 6, wherein the releasing means is positioned at the proximal or distal end of the sample receiving chamber.
8. An assay device according to any preceding claim, wherein the reservoir comprises a puncturable material and the releasing means comprises a puncturing device.
9. An assay device according to any preceding claim, wherein the reservoir is constructed from metal, a metal alloy, a plastic or a polymer.
10. An assay device according to claim 8 or claim 9, wherein the releasing means comprises a pin with a head portion and an elongate pointed shaft extending from the head portion.
11. An assay device according to any preceding claim, wherein the reservoir comprises collapsible walls which are concertinaed by the releasing means, thereby reducing the internal volume of the reservoir and resulting in the ejection of fluid from the reservoir.
12. An assay device according to any preceding claim, wherein the fluid is a liquid.
13. An assay device according to claim 12, wherein the liquid is a buffer solution capable of maintaining the structural and/or functional integrity of the analyte.
14. An assay device according to claim 12 or claim 13, wherein the liquid comprises reagents which are molecular components of the detecting means.
15. An assay device according to any preceding claim, wherein the sample receiving chamber has a protruding thread running helically along the inner surface of the chamber.

472161v1
16. An assay device according to any preceding claim, wherein the detecting means comprises a binding agent capable of binding the analyte.
17. An assay device according to claim 16, wherein the binding agent is immobilised on a solid substrate.
18. An assay device according to any one of claims 1-15, wherein the analyte is an enzyme and the detecting means comprises a substrate for that enzyme which forms a detectable product upon interaction with the enzyme.
19. An assay device according to claim 18, wherein the activity of the enzyme results in a detectable colour change.
20. An assay device according to any preceding claim, wherein the analyte is bacterial sialidase.
21. An assay device according to claim 20 when dependent on claim 18 or 19, wherein the substrate is a salt of 5bromo-4-chloro-3-indoyl a-D-Nacetyl neuraminic acid.
22. An assay device according to claim 21, wherein the substrate is the cyclohexyl amine(X-a-NANA).
23. An assay device according to any preceding claim, wherein the assay device is for detecting the presence of more than one analyte in a sample.
24. An assay device according to claim 23, wherein the analytes are 3galactosaminidase and L-proline aminopeptidase.
25. An assay device according to any preceding claim, wherein the sample receiving chamber, the fluid reservoir, the releasing means and the means for detecting the presence of an analyte are encased in a single housing.

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26. A sampling device for taking a sample from a subject, comprising a shaft having at least one projection extending radially therefrom, the projection forming a substantially continuous peripheral surface around the shaft.
27. A sampling device according to claim 26, wherein the projection forms a protruding thread running helically along the length of the shaft.
28. A sampling device according to claim 26 or 27, wherein the projection forms a surface extending perpendicularly from the shaft.
29. A sampling device according to any one of claims 26-28, which is adapted to take a sample from a bodily orifice of a human subject.
30. A sampling device according to any one of claims 26-29, wherein the projection is constructed of a resilient material.
31. A sampling device according to claim 30, wherein the resilient material is rubber or latex.
32. A sampling device according to any one of claims 26-31, further comprising one or more wing portions extending radially from the shaft.
33. A sampling device according to any one of claims 26-32, which is adapted to form a fluid-tight seal when inserted into an assay device of any one of claims 1-25.
34. An assay kit for detecting an analyte in a sample, said assay kit comprising: a sampling device; and an assay device according to any one of claims 1-25.
35. An assay kit according to claim 34, wherein the sampling device is a sampling device according to any one of claims 26-33.

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36. An assay device substantially as hereinbefore described with reference to and/or as shown in Figure 1 of the accompanying drawings.
37. A sampling device substantially as hereinbefore described with reference to and/or as shown in Figure 2 of the accompanying drawings.
38. An assay kit substantially as hereinbefore described with reference to and/or as shown in Figure 1 of the accompanying drawings.

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