Abstract:
A sterilized device for storing and transferring a tissue sample collected in a sterile field is provided having a hermetically sealed package containing a tissue storage chamber sealed with a removable cap creating a sample storage chamber housing a tissue preservation agent. The package may be provided as a lid sealed to a tray, a plastic bag that is sealed, or two pieces of plastic sealed along the edges. An interior compartment is created within the package, which is sterile along with the sample container and its contents. A tissue preservation agent is provided to stabilized RNA in a tissue sample. The sterilized device is intended for use in storing and transferring a tissue sample from a patient while in a sterile field. The sterilized device is a single assembly that eliminates disrupting a sterile field in an operating room and transferring an exposed tissue sample out of the sterile field.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/532,767, filed Dec. 24, 2003. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a sterile tissue preservation assembly. More particularly, the present invention relates to a sterilized device for storing and transferring a tissue sample from a sterile field.  
         [0004]     2. Description of Related Art  
         [0005]     Tissue storage chambers are used in the process of retrieving and collecting a biological sample for the purpose of storing a preserved tissue sample. More particularly, the tissue storage chamber provides an environment for containing a ribonucleic acid (RNA) preservation agent that preserves and stabilizes the RNA component of a tissue sample. During the process of tissue sample collection, the preservation and stabilization of RNA within the tissue sample is vital to prevent RNA degradation prior to molecular analysis of the tissue sample. Isolating intact RNA is required for quantitative and qualitative analysis of RNA expression by Northern Blot hybridization, nuclease protection assays and reverse transcriptase polymerase chain reaction.  
         [0006]     RNA can be degraded through enzymatic activity and bio-contamination. In order to minimize the activity of RNase liberated during cellular lysis from collected samples such as intact tissues or cells high in endogenous ribonuclease, cells must be quickly homogenized in a powerful protein denaturant such as guanidinium isothiocyanate. Alternatively, intact tissues or cells must be rapidly frozen in liquid nitrogen at &lt;80° C., stored, ground into a powder, and finally homogenized in a RNA extraction buffer when ready for RNA extraction.  
         [0007]     Recently, new methods to preserve RNA in cell and tissue samples were disclosed in U.S. Pat. No. 6,204,375, which has been assigned to Ambion, Inc. The RNA preservation described in U.S. Pat. No. 6,204,375 is marketed by Ambion, Inc. and Qiagen under the trademarks RNAlater™ and RNeasy®, respectively, both sold in non-sterile form. The RNAlater™ and RNeasy® products, both solutions of ammonium sulfate, have provided researchers and doctors the ability to store tissue or cell samples for one day at 37° C., for one week at room temperature, for one month at 4° C., and indefinitely at minus 20° C. or 80° C. The growing use of RNAlater™ and RNeasy® have improved the ability of pathologists to preserve RNA in the hospital setting to some extent, by providing a less labor-intensive method for preserving RNA by submerging a tissue sample in RNAlater™ or RNeasy®.  
         [0008]     Such ammonium sulfate preservation solutions are currently packaged in relatively large (five cc) Nalgene containers or vials. In practice, the surgeon or pathologist transfers the solution from the Nalgene container to a secondary container prior to placing a piece of cellular tissue or blood sample into the secondary container to begin RNA preservation. However, the step of transferring the solution conflicts with operating room procedures relating to sterility. Specifically, maintaining a sterile field and preventing the introduction of pathogenic microorganisms in the blood is one of the most serious concerns in performing surgery. A sterile field is the aseptic area created around a procedure site where only sterile items are allowed. If one non-sterile object or person enters the sterile field, the field is no longer considered sterile.  
         [0009]     The use of ammonium sulfate in current practice in containers in an operating room situation is inadequate for maintaining a sterile field. Accordingly, the collection of a tissue sample in an operating room typically occurs by way of retrieving a tissue specimen from a patient, placing the tissue specimen on a sterile gauze pad moistened with sterile saline and transporting the tissue specimen to a container which is separately filled with RNA preservative from a large supply container. This process is time consuming, and exposes RNA within the tissue sample to the risk of enzymatic degradation in transit and possibly bio-contamination if exposed to contaminated air outside of the sterile field. Clearly, improvements are needed and desired for the steps of collecting a tissue sample and preserving the RNA in the tissue sample, all within the sterile field of the operating room.  
         [0010]     Accordingly, there is a present need for a sterilized device capable of entering the sterile field of an operating room without contamination, which is used for storing and preserving a tissue sample collected in a sterile field.  
       SUMMARY OF THE INVENTION  
       [0011]     Generally, the present invention is directed to a sterilized device, including a hermetically sealed package containing a container sealed with a removable cap and having a tissue storage chamber containing a tissue preservation agent therein. The present invention is an improvement over the prior art as it provides a sterilized container containing a tissue preservation agent sealed in a package with a sterile interior. The present invention is a further improvement over the prior art as it provides a sterilized container capable of entering the sterile field of an operating room without disrupting the sterility of the field. The present invention is an even further improvement over the prior art as it eliminates the need for collecting a tissue sample from a patient in a sterile field, placing the tissue sample on a sterile transfer mechanism and transporting the tissue sample outside of the sterile field for preservation of the tissue and storage in a storage container.  
         [0012]     Specifically, the present invention is a sterilized device comprising a sterilized container sealed with a removable cap that creates a tissue storage chamber containing a tissue preservation agent, whereby the sterilized container is hermetically sealed within a package having a sterile interior. Preferably, the container includes a container with an integrally formed cap. Preferably, the tissue preservation agent is a salt including sulfate salts or any other salt capable of preserving the RNA in a tissue or cell sample.  
         [0013]     Desirably, the package for the container includes a top lid sheet that is hermetically sealed to a bottom tray after the container having a tissue preservation agent therein is placed within the bottom tray. Alternatively, the package for the container may include a plastic bag, which contains the container, and is hermetically sealed at the open end. A further alternative of the package includes two separate, perimetrically-cut, flat pieces of plastic that are hermetically sealed to create an interior compartment or pouch that houses the container with the tissue preservation agent therein.  
         [0014]     Additionally, the present invention involves a method of manufacturing the aforementioned sterilized device. Specifically, the present invention is a method of manufacturing an assembly including the steps of providing a tissue storage chamber, depositing a tissue preservation agent in the tissue storage chamber, closing the tissue storage chamber to maintain the reagent therein, sealing the tissue storage chamber within a container package, and sterilizing the container package containing the tissue storage chamber. Preferably, the step of sterilizing the device includes irradiation of the device. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a perspective view of a tissue storage chamber with a cap removably attached thereto in accordance with the present invention;  
         [0016]      FIG. 2  is a longitudinal cross-section taken along line  2 - 2  of  FIG. 1 ;  
         [0017]      FIG. 3  is a perspective view of a tissue storage chamber which is sealed within a package having a sterile interior in accordance with the present invention;  
         [0018]      FIG. 4  is an exploded view of a tissue storage chamber sealed within a package having a sterile interior as shown in  FIG. 3 ;  
         [0019]      FIG. 5  is a cross-section of the tissue storage chamber sealed within a package having a sterile interior as shown in  FIG. 3 ;  
         [0020]      FIG. 6  is a perspective view of an alternate embodiment of the present invention including a tissue storage chamber sealed within a bag-like package having a sterile interior;  
         [0021]      FIG. 7  is an exploded perspective view of the tissue storage chamber and bag-like package having a sterile interior as shown in  FIG. 6 ; and  
         [0022]      FIG. 8  is a partial cross-section view of the tissue storage chamber sealed within a bag-like package having a sterile interior as shown in  FIG. 6 .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof,  FIGS. 1 through 8  illustrate embodiments of a sterilized device  10  for storing and transferring tissue sample collected in a sterile field comprised of tissue storage chamber  14  with removable cap  40  containing tissue preservation agent  52 , all hermetically sealed within a package such as package  56 ,  56   a,  or  56   b.  The present invention is generally described in terms of sterilized device  10  with several embodiments.  
         [0024]     An embodiment of tissue storage chamber  14  as shown specifically in  FIGS. 1-2  and throughout remaining  FIGS. 3-8  generally comprises cap  40  that is capable of being removably sealed to tissue storage chamber  14 . Generally, tissue storage chamber  14  has upper portion  16 , lower portion  24  and sidewall  30  extending therebetween. Sidewall  30  defines inner surface  32  and outer surface  34 . Upper portion  16  includes open end  18 , and lower portion  24  comprises closed bottom  26 , defining tissue storage chamber  28  therebetween. Annular skirt  36  extends from sidewall  30  in a direction away from upper portion  16  towards lower portion  24 . Annular skirt  36  provides structure for allowing tissue storage chamber  14  to be placed and maintained upright on a flat surface.  
         [0025]     Cap  40  for tissue storage chamber  14  has open end  42 , closed end  44  and sidewall  46  extending therebetween. Cap  40  and tissue storage chamber  14  mate between upper portion  16  of tissue storage chamber  14  and sidewall  46  of cap  40  to secure and seal cap  40  to tissue storage chamber  14  to provide a leak resistant assembly. This may be accomplished by a friction fit, a threaded engagement, a locking cam with lugs or other means common in the art. Strap  48  is provided to connect cap  40  to tissue storage chamber  14 . Strap  48  can be integrally formed with either one of or both cap  40  and tissue storage chamber  14 , desirably forming a unitary structure with a connection web therebetween. The present invention can incorporate one of many embodiments of a tissue storage chamber which may be known in the art.  
         [0026]     Tissue preservation agent  52  is contained within tissue storage chamber  28 . Tissue preservation agent  52  may be any medium that is capable of stabilizing and preserving RNA in a collected tissue or cell sample when that sample is submersed in tissue preservation agent  52 . Preferably, tissue preservation agent  52  comprises a sulfate salt solution. Alternatively, tissue preservation agent  52  comprises a solution including a preservative selected from the group consisting of ammonium sulfate, ammonium bisulfate, ammonium chloride, ammonium acetate, cesium sulfate, cadmium sulfate, cesium iron (II) sulfate, chromium (III) sulfate, cobalt (II) sulfate, copper (II) sulfate, lithium chloride, lithium acetate, lithium sulfate, magnesium sulfate, magnesium chloride, manganese sulfate, manganese chloride, potassium chloride, potassium sulfate, sodium chloride, sodium acetate, sodium sulfate, zinc chloride, zinc acetate, zinc sulfate, methanol, trichloroacetic acid, 1-propanol, 2-propanol, polyethylene glycol, and acetic acid. Tissue preservation agents prepared in accordance with U.S. Pat. No. 6,204,375, incorporated herein by reference thereto, are useful within the scope of the present invention. Tissue preservation agent  52  is comprised of a solution that contains effective amounts of a preservative capable of stabilizing and preserving RNA in a tissue or cell sample for subsequent molecular analysis.  
         [0027]     Particular embodiments of sterile device  10  including tissue storage chamber  14  having cap  40  sealed to tissue storage chamber  14  with tissue preservation agent  52  therein sealed in package  56 ,  56   a,    56   b  present are shown in  FIGS. 3 through 8 . Preferably, package  56  is comprised of top lid sheet  58  hermetically sealed to bottom tray  60  to create interior compartment  68  as shown in  FIGS. 3 through 5 . Top lid sheet  58  comprises a piece of flat plastic or any other material capable of maintaining an airtight seal when sealed to bottom tray  60 . Bottom tray  60 , a three-dimensional structure, is comprised of bottom wall  62 , four sidewalls  64 ,  64   a,    64   b,    64   c  and open top  66 . Bottom tray  60  is comprised of a plastic material or any other material capable of maintaining an airtight seal when sealed to top lid sheet  58 .  
         [0028]     Alternatively, package  56   a  is comprised of polyethylene or polypropylene bag  72  as shown in  FIGS. 6 through 8 . Bag  72  has hermetically sealed edges  74  thereby creating interior compartment  76  that houses tissue storage chamber  14  having cap  40  sealed to tissue storage chamber  14  with tissue preservation agent  52  therein.  
         [0029]     In a further alternative embodiment as shown in  FIGS. 9-10 , package  56   b  comprises two pieces of generally planar sheet material  80 ,  80   a  constructed from a polymeric material such as polyethylene or polypropylene. Such plastic sheet material  80 ,  80   a  may be cut around a perimetrical edge in a desired shape, such as a square, and positioned to sandwich tissue storage chamber  14 , and hermetically sealed along all four edges to create interior compartment  84 .  
         [0030]     In any of the aforementioned embodiments of package  56 ,  56   a,  and  56   b,  sterile interior compartment  68 ,  76 , and  84 , respectively, contains sterile tissue storage chamber  14  containing sterile tissue preservation agent  52 . This sterility provides the means for tissue storage chamber  14  to be removed from package  56 ,  56   a,    56   b  and transported into the sterile field of the operating room. Alternatively, the sterility provides the means for sterile device  10  to be resterilized immediately prior to entry into the sterile field of the operating room. In order to meet sterility requirements for the operating room, sterile interior compartment  68 ,  76 ,  84  of package  56 ,  56   a,    56   b,  respectively, has preferably a sterility assurance level of better than one in one thousand. More preferably, sterile interior compartment  68 ,  76 ,  84  of package  56 ,  56   a,    56   b  has a sterility assurance level of better that one in one million.  
         [0031]     The present invention is also directed to a method of manufacturing the aforementioned embodiments of sterile device  10 . The method comprises the steps of providing tissue storage chamber  14 , depositing into tissue storage chamber  14  tissue preservation agent  52 , closing tissue storage chamber  14  to maintain tissue preservation agent  52  therein with an airtight seal, sealing tissue storage chamber  14  within container package  56 ,  56   a,    56   b,  and sterilizing container package  56 ,  56   a,    56   b  with tissue storage chamber  14  sealed therein. The result of the method of manufacture is sterile device  10  having sterile interior compartment  68 ,  76 ,  84  containing sterile tissue storage chamber  14  containing sterile tissue preservation agent  52 .  
         [0032]     Tissue preservation agent  52  is included within tissue storage chamber  14  in amounts effective for RNA stabilization that are known in the art. An adequate amount of tissue preservation agent  52  is placed in tissue storage chamber  14  to fully submerse any tissue or cell sample placed within tissue storage chamber  14 . After tissue preservation agent  52  is placed within tissue storage chamber  14 , tissue storage chamber  14  is closed by removably sealing cap  40  to tissue storage chamber  14  thereby creating an airtight seal. For example, the airtight seal may be created by a friction fit, a threaded engagement, a locking cam with lugs or other means or structure common in the art, which is based upon the type of tissue storage chamber  14  employed.  
         [0033]     In the present invention, tissue storage chamber  14  with tissue preservation agent  52  sealed therein, is sealed within package  56 ,  56   a,    56   b.  Package  56 ,  56   a,    56   b  is comprised of any one of the packages described and claimed herein, namely one having top lid  58  sealed to bottom tray  60 , bag  72  with the opening sealed, or two square cut pieces of plastic  80 ,  80   a  sealed at all four edges. In a preferred embodiment, top lid  58  is hermetically and removably sealed to bottom tray  60  by heat sealing top lid  58  to bottom tray  60 . An adhesive may also be placed between top lid  58  and bottom tray  60  to seal the two components together. In another preferred embodiment, the open end of bag  72  is hermetically sealed. The sealing may occur by heat sealing an edge  74  of bag  72 . An adhesive may also be incorporated to facilitate the sealing of bag  72 . In a further embodiment, two square-cut pieces of plastic  80 ,  80   a  are hermetically sealed together. The sealing may occur by heat sealing all four edges of the pieces of plastic  80 ,  80   a.  An adhesive may also be incorporated to facilitate the sealing of the pieces of plastic  80 ,  80   a.  In any of the preferred embodiments, once sealed, interior compartment  68 ,  76 ,  84  is created in package  56 ,  56   a,    56   b,  respectively, that houses sealed tissue storage chamber  14  having tissue preservation agent  52  therein.  
         [0034]     A further step of sterilizing device  10  may be provided in the method of manufacture, which comprises irradiating device  10  comprising package  56 ,  56   a,    56   b  with tissue storage chamber  14  containing tissue preservation agent  52  sealed therein. Preferably, the sterilization step comprises subjecting device  10  to Cobalt-60 radiation process, as is known in the art. An effective amount of Cobalt-60 radiation is in the amount of 2.5 to 100 kGy. Alternatively, the sterilization process comprises subjecting the device  10  to electron beam irradiation, or other acceptable sterilization processes that may be known in the art. In any type of sterilization used, the resulting sterilized device  10  possesses interior compartment  68 ,  76 ,  84  with a sterility assurance level of better than one in a thousand and, preferably, better than one in one million.  
         [0035]     While the present invention is satisfied by embodiments in many different forms, there is shown in the drawings and described herein in detail the preferred embodiments of the invention, with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. Various other embodiments will be apparent to and readily made by those skilled in the art without departing from the scope and spirit of the invention. The scope of the invention will be measured by the appended claims and their equivalents.