Abstract:
A freezer bag, a storage system, and a method of freezing are provided. The freezer bag includes a pliable housing having opposing sides and bounding a cavity at least partially disposed between the opposing sides, each opposing side having an interior surface communicating with the cavity and an opposing exterior surface that is openly exposed, the pliable housing including a first panel and a seam. A first tufting couples together the opposing sides of the pliable housing at a distance spaced apart from the seam so that the cavity encircles the first tufting. A first port is connected to the pliable housing and communicates with the cavity.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 14/315,936, filed Jun. 26, 2014, which is hereby incorporated by specific reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to a freezer bag, a storage system, and a method of freezing. More particularly, the present invention is directed to a tufted freezer bag, a storage system including a container for housing the tufted freezer bag, and a method of freezing with the tufted freezer bag. 
       BACKGROUND OF THE INVENTION 
       [0003]    Various liquids, such as culture media, buffers, reagents, bodily fluids, and other biological materials are used extensively in research and development. Often, the liquids include precise compositions with components which begin to degrade after collection or preparation. Due to the degradation of the components, many liquids have finite shelf-lives that limit availability and long-term storage. Additionally, relatively shorter shelf-lives may result in increased costs from increased production and shipping. 
         [0004]    To increase shelf-life, the liquids may be frozen after collection or preparation. Typically, the liquids are collected, prepared, and/or frozen in pliable containers, such as bags. However, due to expansion and uneven freezing, a projection frequently forms on the frozen liquid. The projection creates difficulty in storing multiple containers, and may damage the bags, resulting in contamination, leakage, and/or loss of the liquids. 
         [0005]    One method of reducing damage to the bags includes decreasing the volume of liquid within the bag prior to freezing. However, the decreased volume of liquid still includes an uneven distribution of liquid expansion during freezing, which may damage the bag and create difficulty in storing multiple containers. Furthermore, the decreased volume of liquid increases unused space within the container, which increases shipping cost. 
         [0006]    A freezer bag, storage system, and method of freezing that show one or more improvements in comparison to the prior art would be desirable in the art. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0007]    Exemplary embodiments are directed to freezer bags for increasing uniform freezing of fluids contained therein. 
         [0008]    In one embodiment, a freezer bag includes a pliable housing including at least one panel and a seam, the at least one panel and the seam defining a cavity within the pliable housing, a port extending from the pliable housing, and a tufting coupling opposing sides of the pliable housing, the tufting dividing the cavity into a plurality of regions. 
         [0009]    In another embodiment, a storage system includes a freezer bag and a rigid container. The freezer bag comprises a pliable housing including at least one panel and a seam, the at least one panel and the seam defining a cavity within the pliable housing, a port extending from the pliable housing, and a tufting coupling opposing sides of the pliable housing, the tufting dividing the cavity into a plurality of regions. The rigid container comprises a first portion and a second portion, each portion comprising a dimpled section, a wall, and a plurality of feet. The rigid container is arranged and disposed to receive the freezer bag. 
         [0010]    In another embodiment, a method of freezing includes providing a freezer bag comprising a pliable housing including at least one panel and a seam, the at least one panel and the seam defining a cavity within the pliable housing, a port extending from the pliable housing, and a tufting coupling opposing sides of the pliable housing, the tufting dividing the cavity into a plurality of regions; providing a fluid in the cavity, the fluid at least partially filling each of the regions; and freezing the fluid within the cavity of the freezer bag. The regions increase uniform freezing of the fluid. 
         [0011]    An advantage of exemplary embodiments is that a tufting of the freezer bag forms regions for receiving fluid therein. 
         [0012]    Another advantage of exemplary embodiments is an increase in uniform freezing of fluids contained within the freezer bag. 
         [0013]    Yet another advantage of exemplary embodiments is a reduction or elimination of projections formed during freezing of fluids contained within the freezer bag. 
         [0014]    Still another advantage of exemplary embodiments is that the reduction or elimination of projections facilitates stacking of the freezer bags. 
         [0015]    Another advantage of exemplary embodiments is an ability to maintain freezer bag integrity during freezing. 
         [0016]    Yet another advantage of exemplary embodiments is an ability to store freezer bags in a container without the energy of expansion separating and/or deforming the container during freezing. 
         [0017]    Still another advantage of exemplary embodiments is an ability to freeze an increased volume of fluid without disturbing bag integrity by providing increased uniform freezing of the fluid. 
         [0018]    Other features and advantages of the present invention will be apparent from the following more detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view of a freezer bag, according to an embodiment of the disclosure. 
           [0020]      FIG. 2  is a perspective view of the freezer bag of  FIG. 1  filled with fluid. 
           [0021]      FIG. 3  is a perspective view of a freezer bag, according to an embodiment of the disclosure. 
           [0022]      FIG. 4  is a perspective view of the freezer bag of  FIG. 3  filled with fluid. 
           [0023]      FIG. 5  is a section view of a freezer bag and a conventional bag. 
           [0024]      FIG. 6  is a perspective view of a container for housing the freezer bag of  FIG. 1 . 
           [0025]      FIG. 7  is a perspective view of a container for housing the freezer bag of  FIG. 3 . 
           [0026]      FIG. 8  is a partial cross-sectional perspective view of a stack of the containers of  FIG. 6  in their closed position. 
       
    
    
       [0027]    Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    As illustrated in  FIG. 1 , a freezer bag  100  includes a pliable housing  101 , a tufting  102 , and one or more ports  103 . The pliable housing  101  is formed from any suitable combination of panels  110  and/or seams  112 . For example, in one embodiment the pliable housing  101  includes two panels  110   a ,  110   b  ( FIG. 5 ) secured to each other along a seam  112  to define a cavity configured to receive and hold a fluid, such as a liquid, therein. In another embodiment, the pliable housing  101  includes one panel  110  folded over on itself and secured along the seam  112  to define the cavity. Other embodiments include a plurality of the panels  110  secured to each other along a plurality of seams  112  to define the cavity. 
         [0029]    Each of the panels  110  comprises one or more plies of a flexible sheet or film-like material for providing pliability and support to the liquid contained within the cavity. The material includes any pliable, freeze resistant thermoplastic material and may include, by way of example only, ethylene vinyl acetate. Preferably, USP Class VI materials are employed that are capable of withstanding sterilization without degradation and which do not become brittle at temperatures of up to −70 C or lower. 
         [0030]    The pliable housing  101  can be any shape and/or size as determined by the cavity formed therein. Suitable sizes of the pliable housing  101  include, but are not limited to, greater than about 50 L, between about 50 L and about 200 L, up to about 50 L, between about 100 mL and about 50 L, up to about 25 L, up to about 20 L, between about 100 mL and about 20 L, up to about 16 L, up to about 6 L, about 2 L, between about 100 mL and about 1 L, or any combination, sub-combination, range, or sub-range thereof. Suitable shapes of the pliable housing  101  and/or the cavity include, but are not limited to, spherical, semi-spherical, square, rounded square, rectangular, rounded rectangle, any other rounded or polygonal, or a combination thereof. 
         [0031]    The tufting  102  couples opposing sides of the pliable housing  101  together. As illustrated in  FIGS. 1-2 , a single tufting  102  couples the two panels  110   a ,  110   b  together at a substantially central location within the cavity. In one embodiment, the panels  110  are secured directly to each other to form the tufting  102  by a circular seal  108 . In another embodiment, the panels  110  are coupled through a tufting member, such as, but not limited to, a circular or saucer shaped disk. The tufting  102  may be formed by any sealing technique, such as, but not limited to, heat sealing, radio frequency (RF) sealing, induction sealing, any other film sealing technique, or a combination thereof. The tufting  102  reduces or eliminates movement of the panels  110  relative to each other and reduces or eliminates separation of the panels  110  at the tufting, i.e. in the center of the cavity as shown in  FIGS. 1 and 2 . The seam  112  and the centrally located tufting  102  define a toroid shaped cavity (e.g., torus, doughnut, ring) for receiving a fluid. 
         [0032]    To fill the cavity with fluid, a fluid source is connected to the port  103 . The port  103  is coupled to a break  115  in the seam  112 , the port  103  and the break  115  together providing access to the cavity within the pliable housing  101 . In one embodiment, the port  103  provides a sterile inlet to and/or outlet from the cavity within the pliable housing  101 . As shown in  FIGS. 1-4 , the freezer bag  100  includes a plurality of ports  103 . For example, the plurality of ports  103  may include a male port  105 , a female port  106 , and/or an injection port  107 . Each of the ports  103  may be used to provide fluid to, or remove fluid from, the cavity within the pliable housing  101 . Each of the ports  103  may additionally include a cap, a clamp, and/or any other feature to facilitate coupling of the port  103  and/or control of fluid flow into, or out of, the pliable housing  101 . 
         [0033]    The tufting  102  effectively divides the cavity into separate regions  120  of fluid as the cavity is filled. Filling the pliable housing  101  with fluid expands the cavity, which separates portions of the panels  110  not coupled by the tufting  102  or along the edge at the seam  112 . As the portions of the panels  110  separate, the tufting  102  forms a depression in the pliable housing  101 . The depression formed by the tufting  102  generates recesses  130  in the panels  110 , the recesses  130  defining the regions  120 . The regions  120  are in fluid communication with each other to facilitate the flow of fluid between the regions  120  and allowing a generally equal distribution of fluid about the bag. However, the regions  120  provide identifiable segments of fluid having reduced volume as compared to the entire volume of liquid within the cavity. 
         [0034]    It will be appreciated that in some embodiments, the pliable housing  101  includes more than one tufting  102 . For example, as illustrated in  FIGS. 3-4 , the freezer bag  100  includes at least two of tuftings  102  positioned centrally along a length of the pliable housing  101 . Increasing the number of tuftings  102  increases the number of regions  120  formed in the pliable housing  101 . Additionally, based upon a positioning of the tuftings  102 , increasing the number of regions  120  decreases the size of each region  120 . 
         [0035]    Turning to  FIG. 5 , schematically illustrated is a cross-sectional view of a filled bag having a single tufting in accordance with the embodiment shown in  FIGS. 1 and 2  juxtaposed with a conventional bag  150  shown in dotted line for purposes of comparison. The single tufting is positioned in a location where, without the tufting, the conventional bag  150  would include the largest amount of expansion, i.e., the thickest section of the conventional bag  150  when filled. The fluid in the thickest section is the last to freeze, and where projections from a concentration of fluid expansion would be most likely to occur. The tufting  102  positioned in the thickest section, such as, for example, a central portion of the conventional bag  150 , prevents the thickest section from fully expanding and forms multiple regions  120  having a comparatively smaller thickness than the conventional bag  150 . 
         [0036]    The decreased thickness of each region  120  decreases the thickness of the fluid at any one point in the freezer bag  100 , and thus, decreases the freezer bag  100 ′s ability to form a large “belly”. Additionally, the tufting  102  distributes fluid between the regions  120  around the tufting  102  for a more uniform fluid thickness compared to the conventional bag  150  which expands significantly at the center to form the belly, despite both containing the same amount of fluid. Together, the decreased thickness at any one point and the increased uniformity of thickness throughout the freezer bag  100  provide a more inform freezing of the fluid to decrease or eliminate the formation of projections. By decreasing or eliminating the formation of projections, the tufting  102  can both decrease damage to the freezer bag  100  and increase its stackability. It will be appreciated that the fill volume of the bag, i.e., the volume of the bag which is filled with fluid, is something less than the total volume of the bag in order to accommodate liquid expansion during freezing. By decreasing or eliminating the formation of projections, the tufting permits an increase in the fill volume of the bag. 
         [0037]    The freezer bag  100  may be exposed to a temperature of at −70 ° C. or lower to freeze the fluid. The decreased thickness of the fluid in each of the regions  120  increases uniform freezing of the fluid as compared to the conventional bag  150  having the belly with increased thickness, the central portions of which would take comparatively longer to freeze and decreasing projection (sometime also referred to as cyst or tumor) formation of the liquid that can result during when uneven freezing occurs, particularly as areas in the thickest central portion of the bag remain liquid while the areas around it already have frozen. Additionally, the regions  120  distribute the expansion of the liquid throughout the cavity to reduce the total expansion in any one portion of the freezer bag  100 . 
         [0038]    In one embodiment, the number of tuftings  102  secured to the panels  110  is selected based upon a size of the pliable housing  101  and/or a number of regions  120  to be formed in the pliable housing  101 . For example, a 6 L pliable housing  101  may have a single tufting  102 , while a larger pliable housing  101 , such as a 16 L pliable housing  101 , may include 3-4 of the tuftings  102  to provide an increased number of regions  120 . Additionally, a size of each of the tuftings  102  may be varied, such as, for example, between pliable housings  101  having different sizes. Varying the size of the tufting varies the size of each region  120 , varies the configuration of the regions  120 , varies the strength of the tufting  102 , or a combination thereof. Increasing the number of regions  120  and/or decreasing the size of each region  120  decreases a thickness of the region  120  when filled with liquid. The decreased thickness of the liquid in the region  120  further increases uniform freezing of the liquid and distribution of liquid expansion throughout the cavity. 
         [0039]    The increase in uniform freezing and/or the decreased expansion of liquid in any one portion of the cavity reduces the size and/or formation of projections that may damage the pliable housing  101 . In one embodiment, reducing the size and/or formation of projections facilitates filling the freezer bag  100  with an increased volume of fluid prior to freezing. In a further embodiment, the unfilled volume in the freezer bag  100  provides room for the expansion of the fluid during freezing, while the reduced size and/or formation of projections reduces stress applied by the projections at any one point of the pliable housing  101 . The reduced size and/or formation of the projections also facilitates stacking and/or storage of the freezer bag  100  by forming an exterior surface substantially devoid of projections. 
         [0040]    To further facilitate stacking and/or storage of the freezer bag  100 , a storage system may include the freezer bag  100  and a container  200 . As illustrated in  FIGS. 6-8 , the container  200  includes two portions  200   a  and  200   b . In one embodiment, the two portions  200   a ,  200   b  are minor images of each other. In another embodiment, each portion  200   a ,  200   b  includes a dimpled section  202 , a wall  204 , and a plurality of feet  206 . The two portions  200   a ,  200   b  may be pivotably and/or detachably secured to each other, include corresponding mating features, or a combination thereof. To close the container  200 , the portions  200   a ,  200   b  are positioned opposite each other such that the walls  204  of the portions  200   a ,  200   b  are adjacent and/or in contact with each other. In a further embodiment, the corresponding mating features include extending and/or receiving portions along the wall  204  to orient and/or secure the portions  200   a ,  200   b  together. The container  200  may also include a securing member, such as, but not limited to, a clasp, fastener, or other device to secure the portions  200   a ,  200   b  in a closed position. 
         [0041]    Prior to closing the container  200 , the freezer bag  100  is positioned on the dimpled section  202  of either portion  200   a ,  200   b . In one embodiment, the portions  200   a ,  200   b  are then closed to secure the freezer bag  100  between the dimpled sections  202 . The dimpled sections  202  interlock the freezer bag  100  with the container  200  when the freezer bag  100  is in a frozen state. In another embodiment, each of the sections  200   a ,  200   b  includes a gap  205  in the wall  204 . When the container  200  is closed, the gaps  205  form an opening to facilitate passage of the at least one port  103  therethrough. The closed container  200  including the freezer bag  100  is then positioned in a freezer to freeze the fluid within the freezer bag  100 . 
         [0042]    In one embodiment, stacking the containers  200  includes positioning the feet  206  of one container  200  on or adjacent to the feet  206  of another container  200 . In another embodiment, the plurality of feet  206  includes alternating mating features that facilitate stacking and orienting multiple containers  200  on top of each other. As illustrated in  FIGS. 6-8 , the container  200  includes four feet  206 , two of the feet  206  including a raised rectangular portion, and two of the feet  206  including a recessed rectangular portion. The raised rectangular portions on the feet  206  of one container  200  are positioned within the recessed rectangular portions on the feet  206  of another container  200  to reduce or eliminate movement of the containers  200  relative to each other when stacked. 
         [0043]    In a further embodiment, the feet  206  facilitate uniform freezing of the freezer bags  100  by providing an open space for cold air to flow between the stacked containers  200 . The uniform freezing of the fluid reduces or eliminates the formation of projections during freezing, which reduces or eliminates pressure applied to the container  200  by the projections. By reducing or eliminating the pressure applied to the container  200 , the uniform freezing decreases deformation of container  200 , separation of the portions  200   a ,  200   b , and/or damage to the freezer bag  100  from the projections. 
         [0044]    While the invention has been described with reference to one or more embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.