Abstract:
A controlled transfer biological sample material collection device is disclosed which includes a body and a sample collection member for collecting the biological sample material, the body housing a sample storage medium for generally dry storage of the biological material, the collection member being moveable from an exposed position where collection of a biological sample is possible, to a transfer position which effects transfer of at least a portion of the collected sample to said medium. The body of the device slideably supports the sample collection member, and the body or collection member includes a ramp-like projection portion operable to force the collection member into the transfer position against the medium and to effect the transfer as the collection member slides within the body.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The field of the present invention relates to a controlled transfer biological collection device using a dry solid transfer and storage medium, and a method for the collection of biological material of interest, for example genetic or proteinaceous material, in a form suitable for temporary or long term storage, and/or subsequent analysis. Specifically, the present invention provides for a sampling device that controls the transfer of the biological sample to the storage medium by holding the storage medium and a moveable sample collection member having an analyte collection surface. 
         [0003]    2. Description of the Related Art 
         [0004]    The collection of biological samples (such as blood) and extracting DNA for genetic analysis from the sample has been widely used by the forensics and medical community for identification purposes, for paternity testing, for genetic diagnostic testing in new born screening programs, for genetic typing for predisposition to disease and for genetic characterisation for drug susceptibility. However, due to the invasive nature of blood collection, alternative non-invasive methods are coming into favour. Current methods involve scraping cellular mucosa from inside the oral cavity using any of a number of different devices such as cytobrushes, cotton or artificial fibre swabs, mouthwash swish and rinse methods, foam tipped swabs, and supported cellulosic filter paper collection techniques (known as the Bode method). These methods require time-consuming, labour intensive extraction methods. 
         [0005]    The introduction of treated storage media into the forensics community has significantly streamlined the collection and extraction of DNA from a variety of samples. One such treated medium is available commercially under the brand name FTA® from Whatman, Inc. and is described in one or more of the following patents U.S. Pat. No. 6,627,226, U.S. Pat. No. 6,447,804, U.S. Pat. No. 6,294,203, U.S. Pat. No. 6,168,922, U.S. Pat. No. 5,976,572, U.S. Pat. No. 5,972,386, U.S. Pat. No. 5,939,259, and U.S. Pat. No. 5,756,126. The medium is used with a plastics collecting device known as Easicollect® from Whatman Inc, and described in US20100106057 (Harvey et al). This known collecting device includes an arm having buccal cell collector foam pad at one end, which arm is manipulated to collect buccal cells, and is further manipulated to pivot, and thereby to transfer those cells from the foam pad onto an FTA medium held at an opposing end of the device. 
         [0006]    Whilst this technique is adequate, the transfer buccal cells to the treated medium in a consistent and reproducible manner remains a matter of operator skill, which is not ideal particularly where operators may seldom use the device. The correct pressure and timing of the transfer step are important, and it is essential that the exposed medium is not contaminated while transfer takes place. 
         [0007]    Improvements in the device design were disclosed in WO2012/163788 (GE Healthcare), however, the inventors have realised that yet further improvements in the ease of use and prevention of contamination are possible. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention relates to a controlled transfer biological collection device using a dry solid storage and transfer medium and a method for the collection of biological material of interest—a sample (which may be genetic or proteinaceous material) in a form suitable for storage and/or subsequent analysis. 
         [0009]    According to a first aspect, the invention provides a controlled transfer biological sample material collection device, comprising: a body slideably supporting a sample collection member for collecting the biological sample material of interest, the body housing a treated medium for dry storage of the biological material, the collection member being moveable from an exposed position where collection of a biological sample is possible, to a transfer position which effects transfer of at least a portion of the collected sample to the medium, the device being characterised in that the housing includes a ramp portion operable to force the collection member into the transfer position against the medium and to effect said transfer as the collection member slides within the housing. 
         [0010]    In an embodiment, the collection member includes a portion slideable within the housing which slideable portion carries the medium. 
         [0011]    In an embodiment, the collection member further includes an arm hinged to the slideable portion, which arm carries a resilient pad for sample collection, wherein the slideable portion and the arm are foldable together to slide within the body and together to slide across said ramp to effect the transfer. 
         [0012]    In an embodiment the arm includes a slot, which slot accepts the ramp thereby to separate the medium and the pad following the transfer. 
         [0013]    In an embodiment the slideable portion and medium are positionable within the body so as to be substantially enclosed by the body, and when in that position, the arm is able to adopt said exposed position, and the slideable portion and medium are further positionable so as to be partially within the body but able to adopt said folded together position with the arm, for collective reinsertion into the body and to effect said transfer. 
         [0014]    In an embodiment, the extent of movement of the slideable portion is limited by stops on or in the body. 
         [0015]    In an embodiment, the medium is removable from the slideable portion, following said transfer. 
         [0016]    The invention is further characterised by the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1 a    is a perspective view of a preferred embodiment of the present invention showing the claimed device in an initial position; 
           [0018]      FIG. 1 b    is a plan view of the device shown in  FIG. 1 ; 
           [0019]      FIGS. 1 c  and 1 d    are sections through the device shown in  FIG. 1   b;    
           [0020]      FIGS. 2 a    through to  FIG. 6 d    are further views of the device of  FIG. 1 a   , in different positions. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    A preferred embodiment is shown in  FIG. 1 a   . A collection device ( 10 ) for a biological sample that contains degradable biologically sourced analytes is shown which comprises a body  12  which slideably holds a collection member  20 . The collection member has a sample storage portion in the form of a tray  22  for supporting a sample storage medium  30 . Examples of a storage medium material a suitable for the present invention include untreated filter paper, such as #903® brand paper (Whatman, Inc., Florham Park, N.J. USA) or treated filter papers, such as FTA and FTA Elute brand paper (also from Whatman, Inc., Florham Park, N.J. USA). These treated media are described in US patents referenced above. Such treated media provide a simple safe method for collection, shipping and storage of biological samples. They also contain chemistries which make it easy to isolate DNA from complex samples such as blood. Samples collected on treated or untreated media are dried for storage and can be stored at room temperature for long periods of time. 
         [0022]    The collection member  20  further includes an arm  24  hinged to the sample storage portion by means of a hinge  26  formed from flexible moulded plastics. At the distal end of arm  24  a resilient pad  28  of foamed polymeric material is fixed to the arm, which acts as a sample collector when required. 
         [0023]    In the position shown in  FIGS. 1 a  and 1 b   , the device is ready to be used to collect a biological sample by wiping the pad  28 , or otherwise making contact, over an area of interest, for example to collect buccal cells from the inner cheek surface of the mouth of a subject. 
         [0024]      FIG. 1 b    shows the device  10  in plan view.  FIG. 1 c    shows the device  10  in section along line A-A in  FIG. 1 b   , and  FIG. 1 d    shows the device in section along line B-B. As can be seen in more detail in  FIGS. 1 c  and 1 d   , the tray  22  holds a storage medium  30 , and the  22  is slideable in the body  12  along with the medium  30  and the arm  24 .  5  However, the tray is held resiliently in position by means of detents  21  formed on the tray  22  which cooperate with apertures  14  in the body  12 . 
         [0025]    Once the sample has been collected, the collection member  20  is drawn out of the body  12  as shown in  FIG. 2 a   , until the tray abuts further stop members. Further details are  10  shown in  FIGS. 2 b ,2 c    and  2   d.  In that position, the medium  30  becomes exposed. 
         [0026]    The arm  24  is then folded over toward the medium  30  as illustrated in  FIGS. 3 a ,3 b ,3 c    and  3   d.  In this position, the pad  28  may lightly touch the medium  30  to transfer some biological sample material to the medium but that is not certain. It will be noted that the arm  24  includes a through-slot  23 , the function of which is described in more detail below. 
         [0027]    The user then pushes the collection member  30  back into the body  12  holding the arm folded, as shown in  FIG. 4 a   . The user will feel resistance as the detents  14  abut the edge of the body  12 . At this point a ramp  16  on the body  12  forces the back of the arm  24 , adjacent the pad  28 , toward the medium  28  to provide a repeatable and constant contact force, and thereby a controlled transfer of biological material onto the medium  30  is obtained. 
         [0028]    The user pauses with the device  10  in this position for a predetermined time. It has been found that force is a more accurate predictor of material transference rather than time so the pause time is not critical, but 5 to 15 seconds has proven successful, more preferably about 10 seconds. 
         [0029]    The user then pushes the tray  22  fully into the body  12 , until the pad lifts off the medium  30 . This lifting occurs when the through slot  23  coincides with the ramp  16  so the through slot surrounds the ramp  16 . This position is shown in  FIGS. 5 a ,5 b ,5 c   ,and  5   d.  In this position the complementary features  14  and  21  once again come into alignment. The user can then either remove the medium  30  as shown in  FIG. 6 a ,6 b    and  6   c,  for storage, or transportation to a laboratory for storage or further processing, or may do the same with the whole device still containing the medium  30 . 
         [0030]    Since the medium may contain at least one stabilizing reagent the sample will then be preserved for transport or storage. Suitable such reagents include either the combination of a weak base, a chelating agent, and, optionally, uric acid or a urate salt or simply the addition of a chaotropic salt, alone or in combination with a surfactant. The “weak base” of the composition may be a Lewis base which has a pH of about 6 to 10, preferably about pH 8 to 9.5. One function of the weak base is to act as a buffer to maintain a composition pH of about 6 to 10, preferably about pH 8.0 to 9.5, for example, pH 8.6. Hence, a weak base suitable for the composition of the invention may, in conjunction with other components of the composition, provide a composition pH of 6 to 10, preferably, about pH 8.0 to 9.5. Suitable weak bases according to the invention include organic and inorganic bases. Suitable inorganic weak bases include, for example, an alkali metal carbonate, bicarbonate, phosphate or borate (e.g., sodium, lithium, or potassium carbonate). Suitable organic weak bases include, for example, tris-hydroxymethyl amino methane (Tris), ethanolamine, tri-ethanolamine and glycine and alkaline salts of organic acids (e.g., trisodium citrate). A preferred organic weak base is a weak monovalent organic base, for example, Tris. The Tris may be either a free base or a salt, for example, a carbonate salt. 
         [0031]    A preferred chelating agent is a strong chelating agent. By “strong” chelating agent it is meant that the agent binds multivalent metal ions with a comparable or better affinity than ethylene diamine tetraacetic acid (EDTA). A preferred chelating agent according to the invention is EDTA. 
         [0032]    Anioinic surfactants are examples of surfactants which are useful in the present invention. A preferred anionic detergent is a strong anionic detergent. As used herein, a “strong” anionic detergent includes a hydrocarbon moiety, aliphatic or aromatic, containing one or more anionic groups. Particularly preferred anionic detergents suitable for the invention include sodium dodecyl sulphate (SDS) and sodium lauryl sarcosinate (SLS). In a preferred embodiment, the anionic detergent causes inactivation of most microorganisms which have protein or lipids in their outer membranes or capsids, for example, fungi, bacteria or viruses. This includes microorganisms which may be pathogenic to humans and are present in a biological sample. Also preferably, the storage medium will have a visual delineation ( 32   FIG. 6 a   ) placed around the transfer area of the storage medium such that if removed from the tray  22  a user will know where the material was deposited without reference to the device. 
         [0033]    The present device  10  can be used to collect samples such as degradable biologically sourced analytes such as nucleic acids, proteins, and respective fragments thereof. The biological sample can be selected from the group consisting of saliva, blood, serum, lymph fluids, buccal cells, mucosal cells, cerebrospinal fluid, semen, vaginal fluid, faeces, plasma, urine, a suspension of cells, or a suspension of cells and viruses. 
         [0034]    Preferably, the present device is dimensioned and configured such that tray  22  releasably holds the storage medium  30  by holding means  23  in the form of resilient tabs. Thus, one can separate the medium  30  from the remainder of the device  10  for subsequent processing or storage. The tension on the tabs  23  allows for manual or automated extraction, but does not allow for accidental loss of the medium  30 . 
         [0035]    If used in buccal cell collection, the pad  28  should be dimensioned and configured to fit within the human mouth. For record keeping and traceability the present device should also comprise an identification label (such as conventional bar coding) on not only the medium  30 , but also the body  12 . RFID tags may be employed for this purpose. 
         [0036]    To ensure device integrity, the present device can also comprise a sterility envelope surrounding the other device elements. Preferably, those other elements are sterile and free from any biological sample analytes (made for example, from medical grade plastics), which can be done through conventional techniques such as irradiation after the envelope is sealed. 
         [0037]    Kits can be made that incorporate the above device along with any combination of associated equipment or reagents including purification reagents, buffers, or the like and storage systems, containers, or the like. In this regard, the present invention further provides a kit comprising a device as defined herein and one or more components selected from the group consisting of purification reagents for subsequent analysis of the sample, buffers, storage systems and containers. 
         [0038]    Example of Device Use: 
         [0039]    The present device can be used for biological sample collection for the following purposes: the collection of buccal cell samples for criminal databases; the collection of crime scene samples (i.e., rehydrated blood, semen, saliva and liquid samples of the same); the collection of sexual assault samples; the collection of buccal samples for population genetics or pharmacogenomics studies; the collection of buccal samples for personal genetic ID archiving; the collection of bacterial or parasite samples from food sources; the collection of blood from meat at slaughterhouse for meat traceability; or the collection of biological samples from animals for veterinary diagnostics. 
         [0040]    Although one embodiment only has been illustrated, it will be apparent to the skilled addressee that modifications, variants, additions and omissions are possible within the scope and spirit of the invention defined herein. 
         [0041]    For example, a ramp  16  has been described and illustrated, but any ramp-like projection could be used, i.e. a projection which forms an acute angle between the direction of sliding of the collection member  20  and the surface of the ramp or projection. The acute angle is preferably about 30 degrees as illustrated by the angle x in  FIG. 3 c   . The ramp has been shown on the body  12 , but an equally effective arrangement would be to mount the ramp on the arm  24 , and have a reaction surface on the body. Sliding the arm beyond the reaction surface could release the arm from the transfer position in the same way that the slot  23  releases the arm. ‘Sliding and similar terms mean linear or substantially linear movement. 
         [0042]    Moulded plastics is the preferred material for the body  12  and collection member  20 , but other materials could be employed, for example metals, for example diecast aluminium alloy.