Abstract:
Embodiments of the invention relate to methods of assembling an apparatus for holding biological samples. Conventionally, storage media are encased in a relatively thin flexible cardboard frame. Such constructions are vulnerable to damage from moisture and mechanical forces; these defects may subsequently cause problems for automated handling systems. In an embodiment, these defects are prevented by providing a pair of rigid frames, each frame comprising an aperture; placing a biological sample storage medium between the two frames so that the biological sample storage medium at least partly overlaps each of the apertures in the frames; and joining the two frames to fix the biological sample storage medium in place while allowing access to the biological sample storage medium via each of the apertures. Thus, in embodiments of the present invention, the frames can be rigid and waterproof, and provide a robust storage media for biological samples. At least one pre-defined area of weakness can be provided in the frames, to allow removal of a portion of the frames.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a device for storing and holding biological samples, to a method of assembling a device for storing and holding a biological sample, and a method of analysing a biological sample using the device. 
       BACKGROUND OF THE INVENTION 
       [0002]    Biological samples, such as blood samples taken for drug discovery and saliva taken for DNA profiling in criminal investigations, are typically manually collected and placed on an absorbent storage medium, which may comprise a membrane impregnated with chemicals for stabilising the sample. The samples are allowed to dry and, once dry, the biological storage medium can be transported to a testing facility for analysis. 
         [0003]    Such biological storage media are typically delicate, and require some kind of protective casing for handling and storage. Conventionally, such cases have been constructed of relatively thin, flexible cardboard; however, such cardboard cases suffer from a number of drawbacks. Firstly, cardboard is susceptible to damage by moisture; the constituent components of a cardboard case are likely to warp or even delaminate if the device comes into contact with water. Secondly, cardboard has a relatively low structural strength; rough handling during transport is likely to result in bending, tearing or crushing of the cardboard case. These defects may present problems in subsequent handling. For example, if the sample stored is a test sample, tests may be carried out using robotic or other automated handling systems. If, however, the storage medium and/or the protective case in which it is stored is not flat or is otherwise damaged, this may cause problems for the automatic handling system. 
         [0004]    US20090117011A1 proposes a rigid holder into which the sample card and cardboard case may be inserted to protect it from mechanical damage during transportation. The construction of the device is such that it is also resistant to water to prevent it from warping if it gets wet. However, the rigid holder adds an additional structure to the sample storage device, making it complicated and expensive to manufacture and assemble. Further, the cardboard case and sample storage medium are simply inserted into the rigid holder by aligning the sample card with a groove in the rigid holder; this means that the cardboard case and sample card can easily be removed, or simply fall out during automated or other handling of the device; this may lead to samples being inadvertently misplaced or misdirected, with obvious undesirable consequences. 
         [0005]    It is an object of the present invention to at least mitigate the problems of the prior art. 
         [0006]    In addition, the device of the present invention is, not exclusively, intended for use with an automated punching system which will remove a piece of sample storage medium. Therefore, the device has to be rigid but the sample storage medium has to be assessable to the punching system. Since automated processing of the manually collected sample is envisaged, the need for communicating incorrect/insufficient/contaminated placement of the sample on the medium is desirable. 
       SUMMARY OF THE INVENTION 
       [0007]    In accordance with a first aspect of the present invention, there is provided a method of assembling a device for storing and holding a biological sample, the method comprising: providing a first rigid frame, the first rigid frame comprising a first aperture; placing a biological sample storage medium onto the first rigid frame so that the biological sample storage medium at least partly overlaps said first aperture; placing a second rigid frame comprising a second aperture onto the first rigid frame such that the first and second rigid frames enclose the biological sample storage medium, the second rigid frame being placed such that the second aperture at least partly overlaps the biological sample storage medium; and attaching the first rigid frame to the second rigid frame, thereby holding the biological sample medium between the first rigid frame and the second rigid frame, whereby the biological sample storage medium is accessible via each of said first aperture and said second aperture, the method being characterised in that the first and/or second frame includes least one pre-defined area of weakness for allowing a portion of said frame to be manually removed. 
         [0008]    By sandwiching the biological sample medium between two rigid frames, a sample holding device can be formed which is easily handled, and is robust against damage during handling. Fixing the sample storage medium between the two rigid frames protects it against inadvertent removal and/or falling out of the frames provided. 
         [0009]    Further, since the rigid frames are applied directly to the biological sample storage medium itself, the device is simple, involving relatively few components. Thus, manufacturing and assembly of the device are efficient. 
         [0010]    Preferably, a recess is provided in at least one of the first rigid frame and the second rigid frame, the recess having dimensions arranged to correspond with the biological sample storage medium, the method comprising locating the biological sample storage medium in said recess. Additionally, or alternatively, the method may comprise attaching the biological storage medium to at least one of the first rigid frame and the second rigid frame using an adhesive. Alternatively, or additionally, the at least one of the first rigid frame and the second rigid frame is provided with at least one stake, and the biological sample storage medium is provided with at least one hole, where the number and positions of at least one of the holes corresponds to the number and positions of at least one of the stakes, and the method comprises: locating the at least one stake in the at least one hole; and performing a heat and/or pressure deformation process to deform the at least one stake such that the deformed stake prevents removal of the biological sample storage medium from the first and/or second rigid frame. 
         [0011]    These features provide convenient ways of locating the biological sample storage medium within the first and second rigid frames. 
         [0012]    In some embodiments, one of the first and second rigid frames comprises at least one boss and the other of the rigid frames comprises at least one hole, and the position of the at least one hole corresponds to the position of the at least one boss, the method comprising locating the at least one boss within the at least one hole to align the first rigid frame with the second rigid frame. This provides a convenient way of correctly aligning the two rigid frames together. 
         [0013]    In accordance with another aspect of the present invention, there is provided a device for holding a biological sample, the device comprising: a biological sample storage medium; a first rigid frame comprising a first aperture, the first aperture at least partly overlapping the biological sample storage medium; and a second rigid frame comprising a second aperture, the second aperture at least partly overlapping the biological sample storage medium, wherein the biological sample storage medium is fixed between the first rigid frame and the second rigid frame, and the biological sample storage medium is accessible via each of said first aperture and said second aperture, and wherein the first and/or second frame includes least one pre-defined area of weakness for allowing a portion of said frame to be manually removed. 
         [0014]    In accordance with an alternative embodiment of the invention, there is provided a device for holding a biological sample, the device comprising: a biological sample storage medium; a first rigid frame comprising a first aperture, the first aperture at least partly overlapping the biological sample storage medium; and a second rigid frame comprising a second aperture, the second aperture at least partly overlapping the biological sample storage medium, wherein the biological sample storage medium is fixed between the first rigid frame and the second rigid frame, and the biological sample storage medium is accessible via each of said first aperture and said second aperture, and wherein the first and/or second frame includes least one notch formed in the periphery of said first and/or second frames. 
         [0015]    In some embodiments, the biological sample medium includes a plurality of pre-defined areas for storing a biological sample, and said areas of weakness in at least one of the first or second rigid frames comprises a plurality of removable parts located at positions corresponding to the pre-defined areas. This enables unusable samples to be reliably indicated by removing a part in a position corresponding to an unusable sample. 
         [0016]    In some embodiments, an outer surface of at least one of the first rigid frame and second rigid frame comprises a textured portion. Alternatively, or additionally, an outer surface of at least one of the first and second rigid frames may comprise at least one recess, the at least one recess having a size and shape corresponding to that of an end effector of an automated handling system. These features improve the ease of handling of the device. 
         [0017]    In accordance with yet another aspect of the present invention, there is provided apparatus for storing biological samples, the apparatus comprising; a magazine comprising a plurality of slots for holding a plurality of devices according to the second aspect of the present invention, the devices each including a notch located on an outside edge of the device; and a plurality of devices according to the second aspect of the present invention, wherein each said slot comprises a protrusion having dimensions arranged to correspond to dimensions of said at least one notch. 
         [0018]    These features enable multiple devices to be reliably stored in a predetermined orientation. 
         [0019]    A method of analysing a biological sample employing the device mentioned above is contemplated. 
         [0020]    Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1   a  shows a perspective exploded view of a device for holding a biological sample according to a first embodiment of the present invention; 
           [0022]      FIG. 1   b  shows a perspective view of a device for holding a biological sample according to the first embodiment; 
           [0023]      FIG. 2  shows a perspective exploded view of a device for holding a biological sample holder according to a second embodiment of the present invention; 
           [0024]      FIGS. 3   a  to  3   c  show perspective exploded views of rigid frames and biological sample holding media for assembly of a device for holding a biological sample according to third, fourth and fifth embodiments of the present invention; 
           [0025]      FIG. 4  shows a perspective view of a device for holding a biological sample according to a sixth embodiment of the present invention; 
           [0026]      FIG. 5  shows a front view of a device for holding a biological sample according to a seventh embodiment of the present invention; 
           [0027]      FIG. 6  shows a perspective view of a device for holding a biological sample according to an eighth embodiment of the present invention, and a magazine for storing same; 
           [0028]      FIG. 7   a  shows a perspective view of a biological sample holder according to a ninth embodiment of the present invention; 
           [0029]      FIG. 7   b  shows a perspective view of a biological sample holder according to a tenth embodiment of the present invention, in which the biological sample holder is provided with a textured area for gripping during automated processing; 
           [0030]      FIG. 8  shows a device for holding a biological sample according to an eleventh embodiment of the present invention; 
           [0031]      FIGS. 9   a  and  9   b  show exemplary dimensions of a device for holding a biological sample according to an embodiment of the present invention; 
           [0032]      FIG. 10  shows a twelfth embodiment of an biological sample holder; 
           [0033]      FIG. 11  shows a thirteenth embodiment of an biological sample holder; and 
           [0034]      FIG. 12  shows schematically a method of analysing biological samples stored on the sample holders illustrated in the previous figures. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]      FIG. 1   a  shows a biological sample holder  10  according to an exemplary embodiment of the present invention. The biological sample holder  10  comprises a biological sample storage medium  11  disposed between two rigid (i.e. resistant to deformation under the application of a mechanical force), substantially flat frames  12   a  and  12   b . The frames  12   a ,  12   b  each contain an aperture  13 , (which will be referred to hereafter as a “window”) such that the biological sample storage medium  11  is accessible to a user from either side of the device  10 . 
         [0036]    The frames  12   a ,  12   b  may be manufactured from a plastics material using an injection moulding process. The plastics material used should be selected such that it does not easily deform when exposed to moisture, or externally applied mechanical forces, and may be selected to withstand high temperatures or pressures. This makes the sample holder  10  particularly suited to automated (e.g. robotic) processing, since the sample holder  10  should substantially remain rigid and flat, allowing precision robotic removal and replacement of the samples from and to sample handling magazines, for example. The plastics material may also be selected such that it does not easily build up a static charge when handled, since such static charge can cause problems such as different sample holders  10  sticking together, interfering with handling. An exemplary suitable plastics material is Acrylonitrile Butadiene Styrene (ABS). However, any other suitable plastics material could be used as an alternative. 
         [0037]    The biological sample storage medium  11  is typically an absorbent membrane storage medium, and may be treated with chemicals to stabilise samples stored on the sample storage medium  11 . Examples of suitable storage media include untreated paper such as #903® brand paper (manufactured by Whatman, Inc.), and treated filter papers, such as FTA® and FTA® Elute brand paper (also manufactured by Whatman, Inc). Examples of samples that may be stored include blood, saliva and other bodily fluids. 
         [0038]    During assembly of the holding device, the storage medium  11  is first aligned with one of the frames  12   a ,  12   b  so that at least part of the storage medium overlaps with the window  13  of that frame  12   a ,  12   b . Next, the other frame  12   b ,  12   a  is further aligned so that at least part of the window  13  of this second frame  12   b ,  12   a  overlaps with the storage medium  11 . Typically, the second frame  12   b ,  12   a  is of the same shape and size as the first frame  12   a ,  12   b , and is aligned so that its edges are aligned with those of the first frame  12   a ,  12   b . Once aligned, the two frames  12   a ,  12   b  are attached to one another so that the storage medium  11  is enclosed within the frames  12   a ,  12   b.    
         [0039]    The frames  12   a ,  12   b  may be attached to one another using an ultrasonic welding process, in which the two frames  12   a ,  12   b  are held together, and ultrasonic vibrations are applied to the edges of the frames  12   a ,  12   b  to create a solid-state weld. Alternatively, the two frames  12   a ,  12   b  could be attached to one another, using an adhesive, for example. 
         [0040]      FIG. 1   b  shows an exemplary assembled sample holder  10 . An ultrasonic weld  14  along the peripheral edge of the sample holder  10  substantially permanently holds the frames  12   a ,  12   b  together such that the biological sample storage medium  11  cannot be removed. The sample storage medium  11  is accessible via the window  13  of each the first frame  12   a  and the second frame  12   b . Aside from providing access to the sample, the windows  13  aid ventilation of the sample storage medium  11 , improving drying of the sample, and also allows the sample to be easily removed during subsequent processing, by, for example “punching out” a portion of the sample storage medium  11  holding the sample. 
         [0041]    The alignment of the frames may be facilitated by the use of bosses and holes, as shown in the embodiment of the present invention illustrated in  FIG. 2 . In  FIG. 2 , the first rigid frame  12   a  includes a set of four alignment bosses  16 , and the second rigid frame  12   b  includes a corresponding set of four alignment holes  17 . The bosses  16  and holes  17  are mutually positioned so that when the two frames  12   a ,  12   b  are brought together the bosses  16  fit into the holes  17 . This allows correct positioning of the two frames  12   a ,  12   b  during assembly of the device and preservation of alignment of the two frames during the joining process. 
         [0042]    In some embodiments of the invention, the holder  10  is additionally provided with means for aligning and/or holding the storage medium in the frames  12   a ,  12   b .  FIG. 3   a  shows an exemplary embodiment of the present invention in which edges of the window  13  in the frame  12   a  form a recess  19 , which has dimensions corresponding to those of the sample medium  11 , so that the sample medium is held tightly in place during, and subsequent to, attaching of the first frame  12   a  to the second frame  12   b . Although not shown, it will be appreciated that a corresponding recess is typically provided in the second frame  12   b.    
         [0043]      FIG. 3   b  shows a further embodiment of the present invention, in which a set of holes  20  are provided in the biological sample storage medium  21 , and a corresponding set of stakes  21  are provided protruding from the internal surface of the frame  12   a . During manufacture, the stakes  21  are positioned in the corresponding holes  20  in the biological sample storage medium  11  and heat and pressure is applied to the end of the stakes  21 . This causes the ends of the stakes  21  to deform as shown in the inset to  FIG. 3   b  such that the external diameter of the ends of each stake  21  is larger than the internal diameter of each of the holes  20 . This prevents removal of the biological sample storage medium  21 . 
         [0044]      FIG. 3   c  shows a further embodiment of the present invention in which the frame  12   a  comprises a set of tabs  25  into which the sample storage medium  11  is slid and locked. This method of attaching the sample storage medium  11  to the frame  12   a  can be performed manually or automatically, and avoids exposing the sample storage medium  11  to heat and or pressure. 
         [0045]    In the embodiments described with reference to  FIG. 3   a  to  FIG. 3   c , the second frame  12   b  is typically attached to the first frame  12   a  subsequent to the biological sample storage medium  11  being attached to the first frame  12   a  as described. However, in the case of  FIGS. 3   b  and  3   c , since the biological sample storage medium  11  is permanently attached to the first frame  12   a , it would also be possible to store the biological sample without using the second frame  12   b , in order to reduce costs, for example. 
         [0046]      FIG. 4  shows an embodiment of the present invention in which a biological sample storage medium  11  includes a series of indicia, in the form of indicating marks  28  indicating positions onto which a sample  29  may be placed. The marks  28  may be printed using an ink that is not soluble in water, or in other common solvents. Typically, droplets  30  of a sample liquid are applied to the marked positions using, for example, a pipette  31 , the sample being subsequently allowed to dry. 
         [0047]    Sometimes samples may be considered unusable because, for example, they do not fall correctly within the position marking  28 , or they become contaminated in some way. In order to enable a visual indication of which samples are unusable, in some embodiments of the present invention, removable tags  32  are provided in positions corresponding to the marked sample areas  28 , as shown in  FIG. 5 . The tags  32  may be physically connected to the frames  12   a ,  12   b  by thin sprues  33  formed during the injection moulding process, such that the sprues form an area of weakness in the plastics moulded material. In this embodiment, the sprues  33  are flush with the surface of the frames  12   a ,  12   b  and are sufficiently strong to hold the tag  32  in place. However, the tags  32  may be removed by applying a small amount of pressure directly to the tag  32  when the sample is deemed unsuitable. The result is a distinct marking can be made, corresponding in alignment to the marks  28 , that identifies unsuitable samples, which is visible to users and is also readable by a variety of mark-identifying equipment. Since the removal of the tag  32  is irreversible, it provides an advantage over prior art methods of indicating a bad sample in which a pen or other mark is applied to the sample holder; in these latter methods, the mark may subsequently be ignored or inadvertently removed, which could lead to unsuitable samples being used in subsequent processing. Further, the presence, or otherwise, of a tag  32 , is more easily sensed by automated machinery than the presence, or otherwise, of a pen mark. 
         [0048]    In order to automatically process high volumes of samples, it may be useful to store multiple sample holders  10  in a magazine  36  provided with multiple slots  37  for receiving the sample holder  10 , as shown in  FIG. 6 . The rigid nature of the sample holders  10  makes it particularly suitable for this purpose. Further, in order to avoid misalignment of the card in the magazine  36 , a notch  38  may be provided at an edge of the sample holder  10 . A corresponding protrusion may be provided in each of the receiving slots  37  of the magazine  36 , such that the sample holder  10  can only be fully inserted into the magazine  36  in one orientation e.g. so that the face of the holder  10  on which the sample is located can only face in one direction. 
         [0049]    The magazine  36  may be arranged to conform to a standard SBS (Standard for Biomolecular Sciences) footprint, for ease of use with existing laboratory equipment. For example, the magazine  36  may have a length (L) of 127.76 mm and a width (W) of 85.48 mm. 
         [0050]      FIG. 7   a  shows an embodiment of the present invention in which the surface of at least one of the frames  12   a ,  12   b  includes recesses  40  that correspond to the size and shape of opposing gripper fittings that often form an end effector of a robotic automated handling system. The recesses  40  allow a better grip of the frames  12   a ,  12   b , and more accurate placement of the sample holder  35  in, for example, a testing machine and/or in a magazine  36  such as that described above with reference to  FIG. 6 . 
         [0051]      FIG. 7   b  shows an embodiment of the present invention in which a textured portion  41  is included on the surface of one or both of the frames  12   a ,  12   b  to provide additional grip. This provides an alternative means of improving handling in automated systems. The textured surface may also act as an identification aid to visually impaired people; for example, different textures could indicate different types of sample. 
         [0052]      FIG. 8  shows an embodiment of the present invention in which a printing technique, such as screen printing, is used to print textual information  43  and/or graphical information  44  on the surface of the holder  10 . This information may include instructions, logos, the holder name etc. The print is typically applied in a material that is not easily removed by contact with other parts such as the magazine  36  or a robot end effector, and is not soluble in water or commonly used solvents. 
         [0053]    The external dimensions of the sample holder  10  may be arranged to conform to a magazine  36  having a standard SBS footprint format, as described above in relation to  FIG. 6 . Exemplary dimensions are shown in  FIGS. 9   a  and  9   b , the numbers shown representing millimetres. 
         [0054]      FIG. 10  shows a sample holder  10  generally as described above. In this embodiment, the previously described notch  38  is replaced by a corner notch  58  which is deeper. The corner notch  58  causes the sample holder  10  to stand above of the magazine  36  if it is inadvertently inserted incorrectly. The corner notch  58  is about 8-10 mm deep, and is deeper than the notch  38 , so any upstanding of the sample holder  10  is more pronounced with this corner notch  10 . This deeper notch  58  is formed at one corner of the sample holder  10  so that it is easier to manufacture the deeper notch at that location. 
         [0055]    In addition the sample holder  10  shown in  FIG. 10  has alignment marks  50  which can be recognised by image recognition software, and provide alignment for a punching mechanism (not shown) to remove a piece of the storage medium  11 . 
         [0056]    With additional reference to  FIG. 11 , the sample holder  10  shown includes a protective wrapping  52 , which is held at its captive end  54  between the two frame pieces  12   a  and  12   b , and has a free end  56  which wraps around the sample holder  10  to protect it from contamination. The wrapping  52 , in this case has a fold  58  for folding around the edge of the sample holder  10 . In addition, the sample holder can be held by the wrapping  52  in an upstanding, drying, position as shown in  FIG. 1 , with the aid of a tab  60  folded away from the remainder of the wrapping  52  to keep the sample holder  10  in place. 
         [0057]      FIG. 12  shows a schematic representation of the processing of the biological sample  29  shown in  FIG. 4 . In practice, the sample holder  10  has samples  29  applied to it manually, and multiple holders  10  are loaded into a magazine  36  for automated picking. Once picked, the holder  10  is moved to a punching station  80 , at which a camera  90  is used to analyse the holder  10 . A moveable punch  110  accesses one side of the holder  10 , and a punch backing  120  accesses the opposite side. The punch and backing which are correctly positioned by information from the camera  90 , move toward each other in the direction of arrows A, to remove a sub-sample portion  100  from the holder&#39;s sample storage medium. Each sample  29  can be punched in this way as the punch and backing, move to each identified sample. 
         [0058]    Incorrectly applied samples  29  are indicated by a removed tag  32  and the corresponding sample  29  (if it is present) is ignored. 
         [0059]    The sub-sample  100  is treated, typically by placing the sub-sample portion  100  into a reaction chamber  130  and bio-chemically treating the sub-sample prior to its analysis, according to know techniques. 
         [0060]    The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. For example, although it was described above that the rigid frames  12   a ,  12   b  could be manufactured using an injection moulding technique, other techniques, such as stamping from a plastic sheet could be used. 
         [0061]    In some cases it may be desirable for the rigid frames  12   a ,  12   b  to be re-usable. In such cases, rather than the rigid frames  12   a ,  12   b  being permanently attached to one another, they could be detachably fixed together using, for example, push fasteners. In this way, when a sample storage medium  11  has been used and is no longer needed it can be removed from the frames  12   a ,  12   b , and a new sample storage medium  11  inserted. 
         [0062]    Further, it is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.