Abstract:
Container to be used for preparing a multi-layered blood product by centrifugation, said container comprising a substantially cylindrical body ( 2 ) with a closed bottom ( 3 ) and a top ( 4 ) having a filling opening as well as a filter device ( 15 ), which is slidable inside the container ( 1 ). The filing opening is closed by means of a penetrable membrane ( 13 ), and the filter device ( 15 ) comprises a substantially planar mesh ( 16 ) and a supporting buoyancy body ( 18 ). In addition to this, there are means ( 35, 36, 39, 40, 42 ), for releasable fixation of the filter device ( 15 ) adjacent to the bottom ( 3 ) of the container ( 1 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a container to be used for preparing making a multi-layered blood product by centrifugation, said container comprising a substantially cylindrical body with a closed bottom and a top having a filling opening as well as a filter device, which is slidable inside the container. 
       BACKGROUND 
       [0002]    WO 2010/020254 discloses how to prepare a multi-layered blood product by centrifugation of blood. First, the blood is placed in a container, and the coagulation of the blood is activated during or after placing the blood in the container. During the centrifugation, the components of the blood are separated from each other and produce a three-layered blood product, which in sequential order comprises a first layer, which substantially comprises fibrin, a second, intermediate layer, which substantially comprises thrombocytes, and a third layer, which substantially comprises leukocytes. This three-layered blood product forms a coherent pad, which is separated from serum and erythrocytes. The blood product or the blood pad is suitable for the treatment of wounds. By placing the third layer closest to the wound, the wound is kept substantially aseptic as the leukocytes of the third layer counter infection and attract other cells including macrophages. The second layer substantially comprising thrombocyte contains growth-promoting factors, which stimulate the healing of the wound, whereas the third layer, which comprises substantially fibrin, offers an effective protection against contamination from the surroundings, just as the content of growth-promoting factors of the first layer is released in time. The blood product in question is suitable for autogenic use. Due to a large internal strength, density towards liquids and gasses, the blood product is also suitable for use in other surgical procedures, such as anastomosis, hernioplasties and orthopaedics. 
         [0003]    US 2008/0023414 discloses a container unit for separating blood into a lighter and a heavier constituent by centrifugation. The container unit comprises a tubular body with an interior, a closed bottom and an open top closed by means of a closure. The inner dimension of the tubular body slightly tapers as seen from the top toward the bottom. A separating device is arranged in the interior of the tubular body at the top thereof. The separating device is circumferentially deformable and engages sealingly to the inner surface of the tubular body. When using the container unit, blood is introduced into the interior below the separating device. When the separating device is subjected to centrifugation the separating device moves downwards towards the bottom until it has moved a preselected distance. The lighter constituent flows upwards through the separating device to be situated above the separating device while the heavier constituent is situated below the separating device. 
         [0004]    US 2010/0155319 discloses a separation assembly for separating a fluid such as blood into a heavier fraction and a lighter fraction. The separation assembly comprises a tubular body having a closed bottom end and an open upper end closed by a closure. A separator is displaceably arranged in the interior of the tubular body. The separator comprises a float and ballast, the float and the ballast being connected by bellows sealingly engaging the inner surface of the tubular body when not being subjected to centrifugal force. The overall density of the separator is between that of the heavier and lighter fraction. When using the separation assembly, blood is introduced into the interior of the tubular body below the separator, the separator being initially situated at the top end adjacent the closure. When subjected to centrifugation, the diameter of the bellows decreases and the separator moved downwards toward the bottom until it, due to its overall density, is situated between the lighter and the heavier fraction, the lighter fraction being situated above and the heavier fraction below the separator. 
       DISCLOSURE OF THE INVENTION 
       [0005]    The object of the invention is to provide a container, which is especially suitable for use when preparing said blood product. 
         [0006]    According to the invention, this is achieved by filling opening being closed by a penetrable membrane, that the filter device comprises a substantially planar mesh and a supporting buoyancy body, and that means are provided for releasable fixation of the filter device adjacent to the bottom of the container. 
         [0007]    This container allows for providing of a vacuum in the interior thereof before use. The penetrable membrane allows for easy filling of the container with blood directly from a person, who is to use the blood product. A double needle may be used for the filing, i.e. a needle, which has a cutting edge in both ends, often produced as a thin tube with a needle in both ends. At the same time, the vacuum ensures that the blood is subjected to forces, which may promote the necessary coagulation process, if necessary in combination with the material of which the container is made. The substantially planar mesh of the filter device provides a collecting surface for the blood product during the centrifugation whilst at the same time, heavier parts of the blood, which are still floating, can flow through the mesh down beneath said mesh as the centrifugation is carried out with the bottom of the container facing away from the axis of rotation of the centrifuge. When the blood product has collected above or on the mesh of the filter device, the filter device is appropriately released when stopping the centrifugation or during the subsequent resumption of the centrifugation. This means that the filter device carrying the blood product moves upwards in the container during passing of the liquid blood component, which was situated above the filter device in the container prior to the release of the filter device. When the blood product has moved upwards to the surface of the liquid component in the container, the centrifugation is stopped and the blood product appropriately removed by means of forceps after opening the container appropriately by removing the top. The use of a filter device for collecting the blood product reduces the centrifugation time and the forces compared to a centrifugation without a filter device. The removal of the blood product is facilitated by a filter device with a buoyancy body, which is arranged such that during the centrifugation, the blood product during the continued centrifugation is lifted to the surface of the liquid in the container. The blood product has such strength that it may be removed by means of forceps and applied at a desired spot, e.g. on a wound. 
         [0008]    According to the invention, the filling opening may have a transverse wall placed between the membrane and the inside of the container and having a small passage. Thereby, the blood is subjected to especially great transverse forces during the filling of the container and the presence of a vacuum in the inside of the container. These trans-verse forces promote the initiation of the coagulation process. 
         [0009]    Furthermore, according to the invention, the penetrable membrane may have an annular, protruding and plug-like part at the bottom surface thereof, said plug-like part being adapted to face the inside of the container, and that at the side facing the membrane, the transverse wall has an annular flange extending around the passage and interacting with the protruding plug-like part of the membrane in a tight-fitting way. 
         [0010]    According to the invention, the filling opening may have a transverse wall placed between the membrane and the inside of the container, said transverse wall having a relatively small, penetrable wall thickness. The small wall thickness prevents the needle from being blocked during penetration of the needle of the blood collection set. This wall thickness will depend on the material used. If the membrane is made of Polypropylene, the membrane thickness is preferably less than 0.5 mm. The advantage of the transverse wall without a passage is that the material used will be less permeable than penetration membranes, which are typically made of rubber materials and relatively permeable. In order to ensure a stabile vacuum over time, a membrane of a sealing material will be an advantage. 
         [0011]    In addition to this, according to the invention, the substantially planar mesh ( 16 ) of the filter device may have a downwardly extending skirt, and the buoyancy body is a closed capsule, which is received in the cavity defined by the skirt, and that spacing means are provided for fixing the capsule in a distance from both the bottom surface of the mesh and the inner surface of the skirt. Thereby, an especially easy way is achieved for the filter device to move easily in a free-flowing state inside the container to the surface of the liquid present in the container. The spacing means ensure that the liquid flowing through the filter device during centrifugation can pass the capsule easily and thereby through the filter device during the centrifugation process. 
         [0012]    Advantageously, the spacing means between the mesh and the buoyancy body may be radially extending ribs or rods at the bottom surface of the mesh. Advantageously, these ribs or rods are formed integrally with the mesh. 
         [0013]    Furthermore, the spacing means between the buoyancy body and the skirt may be projections at the lateral face of the buoyancy body and are formed with evenly distributed distances relative to each other along the circumference of the buoyancy body. Advantageously, these projections may be formed integrally with the buoyancy body. 
         [0014]    According to the invention, the capsule forming the buoyancy body is formed by two flat-bottomed bowls engaging each other in a telescope-like way with the bottoms facing away from each other, sealing means being provided for tightly sealing the two bowls together. Thereby, an especially simple and easily manufactured capsule is achieved. 
         [0015]    According to the invention, along the periphery, the skirt of the filter device may have a number of yielding flaps arranged interspaced and each having a radial protruding projection for frictional interaction with the inner face of the container, whereby a good fixation of the filter device is achieved at the bottom of the container before use. 
         [0016]    More appropriately, according to the invention, the container with bottom and top may be rotationally-symmetrically shaped around the longitudinal axis of the cylindrical body, and that the top and the cylindrical body including the bottom are separately formed parts, said parts being adapted to be close-fittingly coupled. 
         [0017]    More appropriately, according to the invention, the mesh of the filter device including the skirt may be integrally formed. 
         [0018]    According to the invention, the means for releasable fixation of the filter device adjacent to the bottom of the container may comprise two cups adapted to be inserted into each other with the mouths facing in the same direction, and where the inner cup is provided with holes for reception of respective slidable squeeze pin extending radially inwardly, the outermost ends of the squeeze pins being adapted to cooperate in a cam follower-like way with the edge of the outer cup when the cups are inserted into each other, whereas the inner most ends of the squeeze pins are adapted to press the wall of the container radially inwards when placing the container with the filter device in the inner cup and thereby fix the filter device in close proximity of the bottom of the container until the two cups are pulled away from each other again. Thereby, an especially simple way for fixation of the filter device at the bottom of the container is achieved as long as desired during the centrifugation. 
         [0019]    Especially appropriate, according to the invention, outer cup may be adapted to be a fixed part of a holder for reception of the container during the centrifugation, and that the cups are telescoped under the influence of the centrifugal force during the centrifugation. Subsequently, the release of the filter device takes place by removing the container with the inner cup from the outer cup and thereafter, the container is placed in the outer cup again without the inner cup with the pins or alternatively with a stabilising second cup without pins. 
         [0020]    Especially appropriate, spring means may be provided between the two cups for moving them automatically away from each other again when stopping the centrifugation, whereby the release of the filter device takes place automatically. 
         [0021]    According to the invention, the inside wall of the outer cup may be provided with at least one groove for co-operation with a guide pin on the inner cup, so that the inner cup is turned a first distance during a telescoped movement of the cups and a subsequent displacement of the cups in a direction away from each other again during a first centrifugation phase and is turned a second distance during a second telescoped movement during a subsequent centrifugation phase, and in that in the end, the squeeze pins are placed opposite each their groove in the outer cup, such that they are released and remain unaffected during a continued centrifugation of the container. Thereby, the release or disengaging of the filter device follows completely automatically simply by stopping the centrifugation, and the centrifugation may be continued without the filter device being retained at the bottom of the container. 
         [0022]    Furthermore, according to the invention, the squeeze pins may be designed to function as guide pins while interacting with corresponding grooves in the outer cup. 
         [0023]    Furthermore, according to the invention, at a level above the mesh, the filter device may carry an easily releasable reinforcement means for the blood product, whereby the inside of the blood product is provided with a reinforcement means, which may function as a reinforcement of the blood product and if desired, be used in connection with a possible sewing on of the blood product to the place of use. 
         [0024]    Finally, according to the invention the reinforcement means may be fixed by means of gravity, whereby it is released especially easy from the filter device by removing the filter device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING(S) 
         [0025]    The invention is explained in detail below with reference to the drawings, in which 
           [0026]      FIG. 1  shows a cross section of an embodiment of a container according to the invention, 
           [0027]      FIG. 2  shows a cross section of another embodiment of a container according to the invention placed in an inner and an outer cup for fixation of the filter device at the bottom of the container, 
           [0028]      FIG. 3  is the same as  FIG. 2 , but seen in another diagonal section and with the filter device being shown schematically, and viewed from the side, 
           [0029]      FIG. 4  is a cross sectional view showing a squeeze pin, and 
           [0030]      FIG. 5  shows a schematic view of a part of the inside of the outer cup shown in  FIGS. 2 and 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    The container shown in  FIG. 1 , which is provided with the general reference number  1 , comprises a rotational-symmetrical, cylindrical body  2  made in one piece with a bottom  3 . At the top or at the other end, the cylindrical body  2  is closed by means of a detachable top  4 , which is tightly sealed to the cylindrical body  2  by means of a seal  5 . The top  4  is also rotationally-symmetrically formed and has a truncated cone-shaped wall  6 , which, in the direction way from the cylindrical body  2 , extends into an annular, radially extending wall  7 , which is delimited by two annular, axially extending flanges  8  and  9 , of which the outer flange  8  has a slightly longer axial direction than the inner flange  9 . At the bottom, the inner flange  9  is formed integrally with a radially extending wall  10  being centrally provided with an axially extending narrow passage  11  and ending on the surface facing the inside of the container  1  in a substantially truncated cone-shaped projection  12  formed integrally with the radial wall  10 . At the top, the top  4  carries a circular, penetrable membrane  13  substantially formed as a disc, but on the one side having an annular protruding part  14 , which interacts with the inner flange  9  at the top  4  in a plug-like way. Along the inner side of the outer flange  8 , the membrane  13  abuts the outer flange  8  tight-fittingly at the top  4 . It may be received in an annular recess in the outer flange  8  (not shown). 
         [0032]    Inside the container  1 , there is a loosely fitted filter device shown by the general reference number  15 . At the top, it comprises a grid or mesh-shaped part  16 , which is formed integrally with an annular skirt  17 . In the cavity defined by the skirt  17 , a capsule-shaped buoyancy body  18  is received, which is formed by two joined cups  19  and  20  formed such that they define a cavity  21  tight-fittingly, if necessary by using an intermediate sealing ring (not shown). Along the periphery of the buoyancy body  18 , projections  22  and  23  are formed with appropriate distance from each other, which maintain the buoyancy body  18  in a distance from the skirt  17  but frictionally engaged therewith. The buoyancy body  18  is also maintained in an appropriate distance from a grid or mesh-shaped part  16  by means of projections  24 ,  25  and  26 , which are formed as one piece with the grid or mesh-shaped part  16 . 
         [0033]    Along the skirt  17 , yielding flaps  27  are formed with appropriate distances from each other by means of axially extending apertures  28  and  29  (see  FIG. 3 ). The flaps  27  between the two apertures  28  and  29  have a projection  30  at the free end, which protrudes in a radial direction. As a result of the projections  30  abutting the inner side of the cylindrical body, these flanges  27  with projections  30  allow for fixation of the filter device  15  at the bottom of the container  1  during transportation. This fixation is achieved by means of friction only. 
         [0034]    In the embodiment shown in  FIG. 1 , upwardly protruding holding means  31 ,  32  and  33  are formed with appropriate distances from each other at the top of the grid or mesh-shaped part  16  of the filter device  15 , said protruding holding means  31 ,  32  and  33  being adapted to support a reinforcement mesh  34 , which is appropriately carried by abutting contact faces on the holding means  31 ,  32  and  33  due to gravity and is in frictional engagement with the holding means  31 ,  32  and  33 . 
         [0035]    In  FIG. 2 , the container  1  is shown in an embodiment without a reinforcement mesh, but with means for releasable fixation of the filter device  15  at the bottom of the container  1  during a centrifugation process. These means comprise two cups, an inner cup  35  and an outer cup  36 , which are formed to be able to be inserted into each other with the mouth facing in the same direction. In a level along the circumference of the inner cup  15 , appropriately spaced holes  37  and  38  are formed for reception of their respective squeeze pin  39  and  40 , adapted to be fixed by means of friction in the respective holes  37  and  38  in the embodiment shown. 
         [0036]    The outer cup  36  has a slanting surface  41  along the upper edge for interaction with the squeeze pins  39  and  40  during telescoping of the cups, the slanting surface  41  displacing the squeeze pins radially inwards in a cam follower-like way. The two cups  35  and  36  are formed in such a way that they may be easily displaced in a direction towards each other and away from each other. The displacement away from each other may be facilitated by means of a schematically shown spring  54 . The pins  39  and  40  are dimensioned in such a way that they push the wall of the cylindrical body  2  of the container  1  somewhat inwards to such an extent that the filter device  15  is fixed at the bottom of the container  1  during the use thereof. 
         [0037]    Appropriately, the outer cup  36  may be a fixed cup in a centrifuge such that during centrifugation, the container  1  is placed therein together with the inner cup  35  and pressed down towards the bottom of the outer cup  36  during centrifugation. 
         [0038]    The container according to the invention is used in the following way. At an appropriate point in time before the container  1  is brought into use, vacuum is established in the container  1  in an appropriate way. When using the container  1 , the membrane  13  is penetrated with a needle, which is connected to a human vein via an appropriate pipe. Assisted by the vacuum in the container  1 , the blood flows into the cavity under the membrane  13  at the top  4  of the container  1 , from where it is sucked through the relatively narrow passage  11  and into the inside of the container  1  as the vacuum therein subjects the blood to large shear forces in the passage, whereupon the blood is sprayed into the interior of the container  1 . Thereby, the initiation of the coagulation process of the blood is facilitated, possibly further facilitated by means of the material, of which the container  1  is made. When the container  1  has been supplied with an appropriate amount of blood, the needle is removed from the membrane  13 , and the container  1  is placed in the inner cup  35 . Together with the inner cup  35 , it is placed in the outer cup  36  in a centrifuge. When the centrifugation is started, the inner cup  35  is pressed down towards the bottom of the outer cup  36 , normally at the same time as the axis of the container is moved into a horizontal or radial position relative to the axis of rotation of the centrifuge. 
         [0039]    During the centrifugation, as mentioned above, the three-layered blood product is produced after an appropriate amount of time (e.g. 8 minutes) and an appropriate application of force. Thereafter, the centrifuge is stopped and the squeeze pins  39 ,  40  are removed, whereupon the centrifugation is resumed. As a result of removing the squeeze pins  39  and  40 , the filter device  15  can now move upwards towards the surface of the liquid, especially as a result of the presence of the buoyancy body  18 . Thereby, the blood product is moved upwards, whereas the surrounding liquid passes through and past the filter device down towards the bottom of the container  1 . When, or a short time after, the filter device has reached the surface of the liquid at the top of the container, or has been stopped when reaching the top  1 , the centrifugation is stopped and the container is removed from the centrifuge. Thereafter, the top  4  is removed from the upper part of the container  1 , and the blood product is now ready to be removed from the container and placed on the desired spot on a patient. 
         [0040]    In connection with the presence of the reinforcement mesh shown in  FIG. 1 , this will, with an appropriate placement on the filter device  15 , be placed on an appropriate place in the blood product, e.g. in the first layer, which comprises mainly fibrin as this layer is the strongest layer. 
         [0041]    Instead of having to remove the squeeze pins manually, they may be preloaded in a direction radially outwards relative to the inner cup. For example, the squeeze pins may be formed as shown in  FIG. 4 , which shows a section of the inner cup  35 , seen in a large scale and with a squeeze pin  42  comprising a bolt-like part  43 , the head  44  of said bolt-like part facing towards the inside of the cup, and a nut  45  having a threaded blindhole supplied with a thread for reception of the bolt  43 . The bolt-like part  43  has a rounded surface for interaction with the slanting surface  41  on the outer cup. By means of a spring  47 , the squeeze pin  42  is preloaded in a position in which the head  44  is aligned with the inside of the cup  35 . Here, the bolt  44  abuts an annular stop face  48  integrally formed with the cup  35 . 
         [0042]    As soon as the outer cup  36  no longer presses the squeeze pin  42  towards the container  1  in the inner cup  35 , the head  44  of the pin  42  is pulled away from its engagement with the container  1 . 
         [0043]    Instead of manually having to remove the container  1  together with the inner cup  35  from the outer cup  36  and thereby ensure the release of the filter device  15 , this process may also be carried out automatically. As shown in  FIGS. 3 and 5 , this may for example take place by forming a groove  49  in the inside of the outer cup  36 . This groove is illustrated in  FIG. 3  by means of a dotted line. The groove  49  is designed to interact with a guide pin  50 , which is fixed to the inner cup  35  in addition to the squeeze pins, which are not shown in  FIG. 3 . The groove  49  may have a course as shown in  FIG. 5 . This course may entail that at first, the guide pin  50  together with the inner cup  35  and the container  1  therein are moved axially downwards in the outer cup  36  until the squeeze pins are activated. During the continued movement of the pin  50 , the inner cup  35  is thereafter, moved from a position a (see  FIG. 5 ) to a position b, where the inner cup  35  with the container  1  is placed during the centrifugation until the bloodproduct is produced. When stopping or braking the centrifugation, the pin  50  is moved from position b to position c as a result of the action of the spring  54 , and in connection with a resumption of the centrifugation, the pin  50  is now moved further down in the outer cup  36  to the position d. During this moving of the position of the pin  50 , the inner cup  35  is turned so far along the inside of the outer cup  36  that the squeeze pins are positioned opposite a groove  51 , which is formed in the outer cup  36  and shown by dotted lines in  FIG. 5 . The position of the squeeze pins  42  opposite this groove  51  means that by means of their respective springs  47 , they are disengaged from the container  1  and thereby release the filter device. The centrifugation process continues with the guide pin  50  in the position d shown in  FIG. 5  until the filter device has moved up to the surface of the liquid in the container  1 . 
         [0044]    The groove shown in  FIG. 5  may have various shapes, but it must have such a shape that it is ensured that the guide pin  50  is moved along the inside of the outer cup  36  such that the squeeze pins are moved into a groove  51 . Appropriately, the groove  51  extends the entire axial length of the inside wall of the outer cup  36  and naturally, there are a number of grooves  51  corresponding to the number of squeeze pins  42  in the inner cup  35 . 
         [0045]    In a preferred embodiment of the invention, the container is made of polyamide, whereas the other parts are made of polypropylene. The reinforcement mesh may be made of Polyglactine, which is a commonly-used degradable suture material. It may also be made of nylon. Depending on the density, it is placed loosely on top of the filter device or by using light barbs. Alternatively, it may also simply be placed anywhere in the container as due to its density, it may move downwards and into engagement with the blood product during the centrifugation. 
         [0046]    In the shown embodiment of the invention, the transverse wall  10  at the top  4  is, as mentioned, designed with a passage  11 . Alternatively, the passage  11  may be omitted. In such case, both the penetrable membrane  11  and the transverse wall  10  are penetrated with a needle during the injection of blood. A suitable diameter of the passage  11  is 0.4 mm. 
         [0047]    The invention has been described referring to preferred embodiments. Many changes may be made without deviating from the scope of the invention. As an example, the hole-delimiting parts of the mesh may have various cross-sectional shapes, but it is preferred that they have a convex shape on the surface facing the blood product.