Support element for a swab and associated system, method and use

Abstract

A support element 5 for a swab 1 comprising a first end forming at least one support surface 6. The swab comprises a hollow member 3 and a strip of flexible sampling material 2. In use the support ele

Description

Technical Field of the Invention The invention relates to a support element for a particular type of commercial-off-the-shelf (COTS) sample swab during the deposition of an agent onto a surface of the swab to enable subsequent testing and evaluation. The invention also relates to an associated system, methods and use. Background to the Invention Testing and evaluation of an agent, in particular a chemical agent in liquid form, can be performed using a non-contact microarray printer, which spot very small volumes of an agent onto a swab surface, analytical sampler or another target. Consistent spot deposition is required for reliable and repeatable test and evaluation. Many varieties of commercial swabs utilise a rounded head of fabric as a sampling surface. A less common swab variety provides a strip of flexible sampling material as the sampling surface. Due to the construction of the latter swab variety, the sampling surface is often curved, rounded or otherwise non-linear, which presents challenges to the spot printing process as the printed sample may roll off the curved sampling surface during deposition. Additionally, consistent spot deposition demands consistent target orientation and consistent spacing between the targets when multiple targets are used in the same printing procedure. However, these targets are often of different sizes and shapes, and the base surface of microarray printers is not generally marked, indented or otherwise manufactured to facilitate their consistent spacing or orientation. There is therefore a need to improve the reliability of sample spot printing, in particular onto swabs that are designed with a curved, rounded or otherwise nonlinear sampling surface. Summary of the Invention According to a first aspect, the invention provides a support element for a swab, the swab comprising: a hollow member with a first opening and a second opening; and a strip of flexible sampling material attached to the hollow member such that the strip of flexible sampling material spans the second opening to provide a non-linear sampling surface, the support element comprising: a) a first end region capable of insertion within the hollow member, the first end region terminating in a first end forming at least one support surface; b) at least a second end; and c) a protruding region, located between the first end and the at least second end, at a defined distance from the first end, the protruding region extending the width of the support element; wherein in use the support element inserts into the first opening of the hollow member of the swab, such that: the at least one support surface protrudes from the second opening and abuts the strip of flexible sampling material; and the defined distance provides for the hollow member of the swab resting upon the protruding region, wherein the at least one support surface provides a tensioning force on the strip of flexible sampling material such that at least part of the strip of sampling material provides a linear sampling surface. The support element advantageously provides a tensioning force to at least part of the underside (relative to placement of an agent) of a specific type of COTS swab (as shown in Figure 1), such that the swab’s flexible sampling material forms a linear sampling surface, thus providing a uniform sampling surface that is better suited to sample spot printing. Furthermore, the support element provides a means to securely hold a sample swab (of the variety described) providing additional stability when test and evaluation procedures are being undertaken. This means is in part provided by the protruding region, extending the width of the support element to a size greater than the first opening of the hollow member of the swab, such that the swab can effectively be seated upon the support element. The protruding region may be provided by an element extending substantially perpendicular to the support element. However, it is envisaged that the protruding region is tapered in design (for example, the widest part of the protruding region is closer to the at least second end region, relative to the first end region, of the support element). The protruding region also prevents the swab from being forced onto on the support element such that the first end region and support surface of the support element protrudes too far from the second opening of the hollow element of the swab, thus preventing the breakage of the swab’s strip of flexible sampling material due to over-tensioning. To achieve this effect, the defined distance from the at least one support surface for the situating of a protruding region must be carefully selected based on the length of the swab and the height from which the sample agent is to be deposited upon the swab sampling surface. It is to be understood that the support element has sufficient rigidity to support the swab, requiring the support element to be made from an appropriately stiff material. In the experience of the inventor, the kind of material used for 3D printing, such as plastic, resins, metal or carbon fibre, provides sufficient stiffness. Preferably, the at least one support surface of the support element is a planar surface to provide a tensioning force. It is to be understood that the planar surface is substantially perpendicular to the longitudinal axis of the first end region of the support element, advantageously providing a tensioning force to the strip of flexible sampling material when abutting said sampling material. A further advantage of the planar surface is its contribution to the ease of manufacture of the overall support element, especially when the support element is 3D printed, when compared to more complex shapes that may be used for the support surface. Alternatively, the first end region comprises a substantially concave surface forming at least one edge region providing the at least one support surface. The edge region can form the point of contact between the concave surface and the strip of flexible sampling material of the swab, advantageously tensioning and flattening the surface of the sampling material. More preferably, the substantially concave surface of the support element is V-shaped. Through experimentation, the inventor has found that a V-shaped surface provides a more consistent tensioning force, and by extension, a more uniformly flat surface on the strip of flexible sampling material than other support element surface shapes. Being axially, reflectionally or rotationally symmetric, the V-shaped concave surface provides the advantage of ease of manufacture of the overall support element, especially when the support element is 3D printed, when compared to more complex concave shapes. The at least second end may engage with a base surface. However, preferably the support element further comprises at least two legs extending from the support element. The at least two legs terminate in respective ends and provide the advantage of increased stability to the overall support element. For example, when adhered to, or provided with a secure connection to, an associated base (the latter achieved e.g. via a complementary set of indents on the base that match the shape of end regions of the legs), the at least two legs are sufficient to provide the required stability. Moreover, the two legs can extend from the support element such that a channel is provided therebetween, said channel providing a means of securing the support element to an associated base e.g. via a complimentary extending element present on, or attached to, the base. Preferably, the at least two legs form the protruding region. For example, the at least two protruding legs form a tapered protruding region. A benefit of this approach is that the region for securing the support element to an associated base and / or extending element is also the region upon which the swab rests, simplifying manufacture while retaining the advantage of preventing the breakage of the strip of flexible sampling material due to over tensioning as described above. Preferably, the at least second end comprises at least one adhesive layer. Alternatively, the at least two legs each comprise at least one adhesive layer. The adhesive layer(s) advantageously provides either permanent or temporary adhesion to a base, depending on the choice of adhesive. This means for securing provides the additional advantages of simplifying the securing method and the manufacture of an associated base. It is to be understood that adhesive layer in this context includes, but is not limited to, glue, epoxy or adhesive tapes. According to a second aspect, the invention provides a system comprising a) at least one support element according to the first aspect; and b) a base surface. The base surface provides additional stability for the at least one the support element during sample deposition. This can be achieved by the support element and base being of unitary construction (i.e. a single integral component forming both the base and support element), or by the support element and base being separate components that are connected and / or joined. For example, the base provides a surface for engagement wherein the means for securing the separate support element to the base is at least one adhesive layer, when the support element and base are separate components. Depending on the modifications to the base, there may be the possibility of additionally securing support elements for different swab types, sample vials and other sampling surfaces. The base may allow for repeatable spacing of support elements / swabs during sample deposition, increasing the usability and / or reliability of the sample deposition process, especially if the samples are deposited via a printer or similar automatic means. Preferably, the base surface comprises at least one indent and / or extending element, complementary to at least part of the at least second end and / or protruding region of the support element, such that a push-to-connect fitting can be formed between the support element and the base. It is to be understood that the term “indent” in this context refers to a depression that is cut, carved or otherwise situated into the otherwise planar surface of the base and / or extending element. When the support element is to be securely attached to the base surface without the use of a separate extending element, a preferred indent is one matching in shape to that the at least second end of the support element, with a cross sectional area slightly larger than that of the at least second end of the support element, such that an interference fit is achieved when the at least second end of the support element is slotted into the indent situated in the base surface or in an extending element associated with the base. It is to be understood that the term ’extending element’ in this context refers to a projection from the planar surface of the base that is capable of engaging with the at least second end and / or protruding region of the support element. The base and extending element can be of unitary construction, or the extending element can be a separate element that engages with the base. A preferred extending element is one with an indent matching in shape to that of the at least second end of the support element, with a cross sectional area slightly larger than that of the at least second end of the support element, such that an interference fit is achieved when the at least second end of the support element is slotted into the indent. Another preferred extending element, used when the element further comprises at least two legs extending from the support element, is one with a notch, slot or other type of depression cut into the projection, which can accommodate part of the at least second end and / or protruding region of the support element, with the support element legs situated either side of the extending element such that a push-to-connect fitting between the support element and extending element is achieved. When the support element is to be attached to a separate extending element that is then attached to the base surface, a preferred extending element is one with one or more feet that engage(s) with a base surface ident matching in shape to that of the foot / feet of the extending element, such that an interference fit is achieved when the foot / feet of the extending element is slotted into the indent situated in the base. The presence of at least one indent and / or extending element advantageously provides a means for firmly securing the support element to the base in a way that is easy to manufacture, particularly when the base is 3D printed. The additive process used for typical 3D printing creates parts made layer-by-layer, leading to a rough textured surface. When the at least second end and / or protruding region of the support element and indent situated in the base surface (or into an extending element) are designed with a respective inference fit, this enables a secure connection, removing the need for adhesive. Such design can also be applied as required to the foot / feet of a separate extending element to enable an interference fit with an indent situated in the base. The indent(s) and / or extending element(s) can be regularly spaced on the base, providing repeatable sample deposition positions, which provides a particular advantage in terms of increasing the usability and / or reliability of the sample deposition process, especially if the samples are deposited via a printer or similar automatic means. To further ensure repeatable and reliable sample deposition, a preferred shape of the indent(s) and / or extending element(s) feet is asymmetric, ensuring that the support element and the swab it holds can only be secured in one rotational orientation. According to a third aspect, the invention provides a method of arranging a swab on a support element comprising the step of inserting the support element of the first aspect into the first opening of the hollow member of the swab such that: the at least one support surface protrudes from the second opening and abuts the strip of flexible sampling material; and the hollow member rests upon the protruding region, wherein the at last one support surface provides a tensioning force on the strip of flexible sampling material such that at least part of the strip of sampling material provides a linear sampling surface. According to a fourth aspect, the invention provides a method of arranging a swab on a support element comprising the steps of: a) arranging the system according to the second aspect, such that the support element is secured to the base; and b) performing the method of the third aspect. It is to be understood that these method steps a) and b) can be performed in either order i.e. a) followed by b), or b) followed by a). According to a fifth aspect, the invention provides a method of placing an agent on a swab comprising the steps of a) undertaking the method according to the third aspect or fourth aspect; and b) placing an agent on the strip of sampling material providing a linear sampling surface. In particular, one envisaged potential method for the placing of an agent on the strip of sampling material is with a non-contact microarray printer. However, other approaches such as manual or automatic pipette droppers are applicable. The act of placing an agent upon a sampling surface of the particular swab associated with the invention is aided by the tensioning force provided by the support surface of the support element ensuring a linear sampling surface of the swab. According to a sixth aspect, the invention provides use of the support element according the first aspect, or a system according the second aspect. In particular, it is envisaged that one potential use of the described system is for the preparation of potentially hazardous substances for further testing, where there is a clear need to prevent the sample from rolling off the sampling surface in order to prevent contamination of surrounding equipment. However, the support element and system are suitable for use in more general sample characterisation, such as the preparation of samples for protein and antibody characterisation, drug target identification, biologies discovery and autoimmunity and / or serology profiling. Any feature in one aspect of the invention may be applied to any other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus, system and / or use aspects and vice versa. The invention extends to a method, apparatus, system or use substantially as herein described, with reference to the accompanying Figures. In all aspects, the invention may comprise, consist essentially of, or consist of any feature or combination of features. Description of the Figures The present invention will now be described, purely by way of non-limiting example, with reference to the accompanying Figures, in which: Figure 1 shows an isometric view of a particular COTS sample swab for use with the support element of the invention; Figure 2 shows an isometric view of a support element according to one preferred embodiment of the invention; Figure 3 shows an isometric view of an extending element, according to one preferred embodiment of the system of the invention; Figure 4 shows an isometric view of the support element of Figure 2, and extending element of Figure 3 in use with the COTS sample swab of Figure 1; Figure 5 shows an isometric view of a base plate according to one preferred embodiment of the system of the invention; and Figure 6 shows an isometric view of the base plate of Figure 5 in use with a plurality of support elements and extending elements of Figure 2 and Figure 3 respectively. The drawings are for illustrative purposes only and are not to scale. Detailed Description Figure 1 shows a typical COTS swab (1), providing a strip of flexible sampling material (2) as the sampling surface shown in its original, untensioned state. The flexible sampling material is adhered to the top of a hollow body (3) which has a first opening (not shown) on the underside of hollow body (3) and a second opening (4) across which spans the strip of flexible sampling material (2). The length of the COTS swab (1) (including the hollow body (3) and untensioned sampling material (2)) is approximately 18.5mm. The hollow body (3) of the COTS swab has a rectangular cross section of approximately 10mm width and approximately 8.5mm depth. From this arrangement, it can be seen that printing liquid samples onto this type of sample swab would be challenging, as the printed sample may roll off the curved sampling surface provided by the flexible sampling material (2) during deposition. Figure 2 shows a support element (5) consisting of a V-shaped support surface (6) at a first end region, atop a body (7) from which two legs (8a, 8b) extend. The support element (5) has a total height (including the V-shaped support surface (6) and legs (8a, 8b)) of approximately 39mm. The maximum width of the support element (5) is approximately 18mm, situated at the terminus of the two legs (8a, 8b). The maximum depth of the support element (5) is approximately 10mm, situated at the terminus of the two legs (8a, 8b). There is a spacing of approximately 5mm between the points that form the V-shaped support surface (6). With reference to Figure 1 and Figure 2, in use, the first end region (6) of support element (5) terminating in a V-shaped support surface (6) is pushed through (via the first opening (not shown)) the second opening (4) of the hollow swab body (3). The length of the support element body (7) and the width of the two legs (8a, 8b) is such that the bottom of the swab body (3) rests upon the two legs (8a, 8b), whilst the V-shaped support surface (6) protrudes through the second opening of the hollow swab body (3), abutting the strip of flexible sampling material (2). The tensioning force asserted by the abutting provides a linear sampling surface, reducing the likelihood of the printed liquid sample rolling off the sampling surface (2). Figure 3 shows an isometric view of an extending element (9) consisting of a foot (10) for housing within a separate base plate (see Figure 5 and Figure 6) from which extends a protruding body (11) into which a notch (12) is cut. The extending element (9) has a height of approximately 36mm. The foot (10) of the support element has a width of approximately 40mm and a depth of approximately 20mm. With reference to Figure 2 and Figure 3, in use, the body (7) of the support element (5) is inserted into the notch (12) of the extending element (9), with the support element legs (8a, 8b) situated either side of the protruding body (11) of the extending element (9), providing a push-to-connect fitting between the support element (5) and the extending element (9). Figure 4 shows an isometric view of the COTS swab (1) of Figure 1, support element (5) of Figure 2, and extending element (9) of Figure 3 in use. In particular, Figure 4 demonstrates how the V-shaped support surface (6) protrudes through the second opening (via the first opening) of the hollow swab body (3) to abut the strip of flexible sampling material (2) such that the resulting tensioning force asserted by the V-shaped support surface (6) provides a linear sampling surface. The length of the support element body ((7), not shown in Figure 4) is carefully chosen such that when the bottom of the swab body (3) rests upon the two legs (8a, 8b), the first end region terminating in a V-shaped support surface (6) cannot be pushed through the hollow swab body (3) in a manner that provides for over-tensioning and potential breakage of the strip of flexible sampling material (2). Figure 5 shows an isometric view of a base plate (13) for housing an extending element (not shown) and associated support element (not shown), comprising a base plate body (14) having screw holes (15) and regularly spaced indentations (16), the latter interposed to house foot (10) of an extending element (not shown). The regularly spaced indentations (16) provide a plurality of sample deposition positions for printing. The indentations (16) of baseplate (13) are shaped such that, in use, the extending element (9) of Figure 3 with a correspondingly shaped foot (10) can only be housed in one particular rotational orientation, ensuring repeatable and reliable sample deposition. Screw holes (15) are interposed at regular intervals allowing the baseplate body (14) to be securely attached to the printing area of a non-contact microarray printer or similar printer. The base plate body (14) has a height of approximately 6mm, a width of approximately 230mm and a depth of approximately 50mm. The spacing between the regularly spaced indentations (16) is approximately 5mm. The spacing between the screw holes (15) is approximately 84mm. Figure 6 shows an isometric view of the support element (5) of Figure 2, the extending element (9) of Figure 3 and baseplate (13) of Figure 5 in use. Figure 6 demonstrates how the push-to-connect fitting between the support element and the extending element is achieved, as well as showing the housing of the extending element into the indentations (16) of the baseplate is achieved. Figure 6 demonstrates the arrangement of multiple support elements connected to their respective extending elements within a single baseplate, as well as the ability to house holders (17) for different samplers or vials within the baseplate. In use, the baseplate body (14) is securely screwed to the printing area through the screw holes (15). Multiple extending elements (9) and / or holders (17) for different vials and / or samplers are housed within the baseplate indentations (16). Support elements (5) are connected to the extending elements (9), and / or different vials and / or samplers are held within their respective holders (17). Sample swabs (not shown) are held and have their flexible sampling material (2) tensioned by the support element (5). Small volumes of samples of agents in liquid form are then dropped onto the sampling materials (2) and / or into other vials and / or samplers to enable testing and evaluation. It will be understood that the present invention has been described above purely by way of example, and modification of detail can be made within the scope of the invention. Each feature disclosed in the description, and (where appropriate) the claims and may be provided independently or in any appropriate combination. Moreover, the invention has been described with specific reference to deposition of an agent, in particular a chemical agent in liquid form, deposited using a non-contact microarray printer. It will be understood that this is not intended to be limiting and the invention may be used more generally. For example, the invention may be used in sample deposition (in biological, biomedical and food safety applications, amongst others). The invention may also be used in the field of material science for the deposition of nanoparticle, polymers, or other materials onto non-linear surfaces. Additional applications of the invention will occur to the skilled person.

Claims

1. A support element for a swab, the swab comprising: a hollow member with a first opening and a second opening; and a strip of flexible sampling material attached to the hollow member such that the strip of flexible sampling material spans the second opening to provide a non-linear sampling surface, the support element comprising:a. a first end region capable of insertion within the hollow member, the first end region terminating in a first end forming at least one support surface;b. at least a second end; andc. a protruding region located between the first end and the at least second end, at a defined distance from the first end, the protruding region extending the width of the support element;wherein in use the support element inserts into the first opening of the hollow member of the swab such that: the at least one support surface protrudes from the second opening and abuts the strip of flexible sampling material; and the defined distance provides for the hollow member of the swab resting upon the protruding region, wherein the at least one support surface provides a tensioning force on the strip of flexible sampling material such that at least part of the strip of sampling material provides a linear sampling surface.

2. A support element according to Claim 1 wherein the at least one support surface is a planar surface substantially perpendicular to the longitudinal axis of the first end region of the support element.

3. A support element according to Claim 1, wherein the first end region comprises a substantially concave surface forming at least one edge region providing the at least one support surface.

4. A support element according to Claim 3, wherein the substantially concave surface is V-shaped.

5. A support element according to any preceding claim, further comprising at least two legs extending from the support element.

6. A support element according to Claim 5, wherein the at least two legs form the protruding region.

7. A support element according to Claim 1 to Claim 4, wherein the at least second end comprises at least one adhesive layer.

8. A support element according to Claim 5 to Claim 6, wherein the at least two legs each comprise at least one adhesive layer.

9. A system comprising:a. at least one support element according to any one of Claim 1 to Claim 8; andb. a base surface.

10. A system according to Claim 9, wherein the base surface comprises at least one indent and / or extending element, complementary to at least part of the at least second end and / or protruding region of the support element, such that a push-to-connect fitting can be formed between the support element and the base.

11. A method of arranging a swab on a support element comprising the step of inserting the support element of Claim 1 to Claim 8 into the first opening of the hollow member of the swab such that: the at least one support surface protrudes from the second opening and abuts the strip of flexible sampling material; and the hollow member rests upon the protruding region, wherein the at last one support surface provides a tensioning force on the strip of flexible sampling material such that at least part of the strip of sampling material provides a linear sampling surface.

12. A method of arranging a swab on a support element comprising the steps of:a. arranging the system of any one of Claim 9 to Claim 10 such that the support element is secured to the base; andb. performing the method of Claim 11.5 13. A method of placing an agent on a swab comprising the steps of:a. Undertaking the method of any one of Claim 11 to Claim 12; andb. placing an agent on the strip of sampling material providing a linear sampling surface.io 14. Use of support element according to any one of Claim 1 to Claim 8, or the system according to any one of Claim 9 to Claim 10.

Images