The present invention generally pertains to devices for cryopreservation of cells and/or tissues, and more specifically to cryogenic storage containers (i.e., “cryostorage containers”) useful for the cryopreservation of biological material (e.g., cells and/or tissues), such as mammalian cells and tissue samples/specimens.
Cells and tissues are frequently cryopreserved to temporally extend their viability and usefulness in biomedical applications. The process of cryopreservation involves, in part, placing cells into aqueous solutions containing electrolytes and chemical compounds that protect the cells during the freezing process (cryoprotectants). The freezing process, however, is not as benign as one might assume; it generally induces extreme variations in chemical, thermal, and electrical properties that could be expected to alter intracellular organelles, cellular membranes, and the delicate cell-cell interaction systems associated with tissues and organs.
As aqueous solutions containing cryoprotectants and cells are cooled to temperatures slightly below their freezing point, the solutions remain in the liquid state. This condition in which such a solution remains liquid below its phase transition temperature is termed supercooling. As the aqueous solutions are cooled further below their freezing point, the extent of supercooling increases. In the absence of intervention, the water molecules in the solution will, at a point usually no more than 15° C. below the freezing point, spontaneously crystallize, and pure water will precipitate as ice.
During the transition from the liquid to the solid state, the solution moves from a higher to a lower free energy state, resulting in an exothermic reaction. The heat produced during this phase transition causes a transient warming of the sample during which the sample temperature increases. Meanwhile the surrounding environment (e.g., the device in which the sample is being cryopreserved) either remains at a constant temperature or continues to cool (depending upon the cooling approach used).
Subsequently, as the heat in the sample dissipates, the thermal disequilibrium between the sample and cooling device created during this event causes the sample to undergo a rapid cooling rate to re-establish thermal equilibrium. In many cases this rapid cooling rate causes the formation of intracellular ice, which usually results in cell death. This formation of intracellular ice is typically dependent upon the mass of the sample, the heat transfer properties of the sample container, the cooling protocol used, and the fundamental cryobiological properties of the cells.
Notably, deviations from the cooling rate and/or thawing rate prescribed for a particular cell type can lead to cell damage and/or cell death during the process. Conventional cryogenic storage containers useful to directly hold biological material for cryopreservation have shapes and sizes that enable or result in deviations of the cooling rate and/or thawing rate across a volume of the biological material. Vials, for example, which are conventionally used to directly hold biological material during cryopreservation, can yield significant variations in the cooling rate and/or thawing rate across a volume of biological material contained therein. Vials are often positioned within a cryostorage/freezer box, which holds multiple samples and aids in the locating and retrieval of the vials from cryostorage. Some boxes aid in limiting the freezing rate of the biological sample positioned within the vial. For example, some cryostorage/freezer boxes are formed of a foam material that provides thermal insulation. The freezing profile of the sample within the vial, however, is still impacted by the shape and size of the vial.
In small cylindrical vials (e.g., large enough to hold 5 ml or less) substantially all the sample freezes at the same rate. In larger diameter cylindrical vials (e.g., large enough to hold 10 ml or more, 20 ml or more, 30 ml or more, 40 ml or more, and/or 50 ml or more), however, portions in the middle of these larger diameter vials take substantially longer to freeze. These middle portions, therefore, have different cell viability results than other portions within these larger diameter vials.
There remains a need for devices that reduce and/or avoid the problems associated with the disequilibrium conditions described above. Thus, there is a need for improvement in this field.
Containers for cryopreservation, as disclosed herein, are arranged to provide a substantially consistent freeze profile throughout a chamber of the container. Such arrangements facilitate freezing of the contents of the cryostorage container, such as cells, at a constant rate or a more constant rate to reduce the likelihood of damage to the cells during freeze and/or thaw cycles. (In some instances herein, the terms “freeze cycle”, “freeze profile”, or another similar term are used for brevity. It should be understood, however, that containers according to the present disclosure may provide similar advantages to thawing cycles, thawing profiles, and the like).
Cryopreservation containers disclosed herein can be provided with uniform characteristic dimensions and high dimensional aspect ratios while facilitating or maintaining freeze/thaw consistency and while having relatively large capacities compared to conventional or previously existing vials and bags for cryostorage. For example, the cryopreservation containers disclosed herein can be arranged to hold 30 ml or more.
Some embodiments of a cryostorage container may comprise a serpentine chamber for holding a volume of liquid, a vent opening and a drain opening each communicating with the serpentine chamber, a filter associated with the vent opening to filter air entering and/or exiting the serpentine chamber when in communication with a surrounding environment, a first end region, and a second end region. The serpentine chamber may be defined at least partially by a first wall and a second wall, wherein the first wall follows a serpentine path from the first end region of the cryostorage container to the second end region of the cryostorage container. The serpentine path can be defined by a series of straight portions forming a zig-zag or chevron pattern. The serpentine path can additionally or alternatively be defined at least partially by a series of curves bending in alternating directions. The series of curves can be separated by straight portions.
In some embodiments, the second wall can be spaced from the first wall along the serpentine path such that the chamber has a uniform width between the first wall and the second wall along the serpentine path. For example, the width of the chamber between the second wall and the first wall, measured along a vector normal to the first wall, can be at or between 5 mm and 7 mm.
In some embodiments, the cryostorage container can comprise heat-sealable tubing attached to the drain opening and/or the vent opening. The heat-sealable tubing can retain a filter, particularly if the heat-sealable tubing is attached to the vent opening.
In some embodiments, the vent opening can be positioned at a first end of the serpentine chamber and/or the drain opening can be positioned at a second end of the serpentine chamber. The serpentine path can have a length extending from the first end to the second end. The length can be greater than a width and/or a height of the serpentine chamber.
In some embodiments, the cryostorage container can comprise a hanger opening arranged to receive an IV bag hanger. The hanger opening can be positioned at an opposing end of the cryostorage container relative to the drain opening such that when the cryostorage container hangs freely from an IV hanger, the drain opening is at the lowest portion of the serpentine chamber. The hanger opening can be off-center along the end of the cryostorage container.
Cryostorage containers of the present disclosure may comprise: a chamber having a volume; the chamber defined by wall portions of the cryostorage container and wherein the wall portions of the cryostorage container each have an interior surface facing the chamber and an exterior surface opposing the interior surface; and wherein each interior surface has a surface area and wherein a ratio of a sum of the surface areas to the volume of the chamber is at or between 1 to 5 and 2 to 5. The wall portions defining the chamber may follow a serpentine path from a first end of the chamber to a second end of the chamber. The chamber may have a length extending from the first end to the second end and a uniform width along the length. The width may be at or between 5 mm and 7 mm. The ratio may be at or between 3 to 10 and 2 to 5. In any of the disclosed arrangements, the ratio can be about 1 to 3.
The wall portions of the containers may have a thermal conductivity at or between 0.16×10-3 watts per Kelvin and 0.32×10-3 watts per Kelvin at room temperature. In any of the disclosed arrangements, the wall portions may comprise a material having a thermal conductivity at or between 0.10 to 0.20 W/m K at room temperature. The body and/or lid may be formed of a polymer such as cyclic olefin copolymer. The polymer may be doped with nanoparticles (e.g., metals) to increase the thermal conductivity of the material.
Advantageously, the exemplary cryostorage container illustrated in the provided figures can be oriented in multiple directions. For example, the cryostorage container can be positioned with the feet on a supporting surface and the vent and drain openings of the lid located at an uppermost portion of the cryostorage container. The cryostorage container may also be oriented with the drain opening positioned at the lowest point of the chamber so that essentially all the liquid contained in the chamber will drain out through the drain opening. In such an arrangement, the vent opening will also be positioned at an upper portion of the chamber so as to allow air to enter the chamber without mixing in the liquid being drained and/or allowing liquid to escape the chamber through the vent opening. During a drain procedure, air entering the chamber through the vent opening is filtered by the filter associated with the vent opening to avoid contamination of the interior volume of the serpentine chamber.
It will be appreciated by those of skill in the art that the cryostorage container may be formed by a variety of manufacturing techniques, such as injection molding, blow molding, rotational molding, gas assist molding, and rapid prototyping, just to name a few non-limiting examples. The body and lid may be manufactured separately and then attached together, such as by adhesive, ultrasonic welding, hot plate welding, infrared welding, and/or laser welding. In some of the manufacturing techniques (e.g., rapid prototyping) the lid and body may be manufactured as a unitary body. The cryostorage container in the illustrated embodiments can be formed by at least injection molding and rapid prototyping. Preferably, regardless of manufacturing technique, the container will be hermetically sealable.
Cryostorage containers of this disclosure preferably have rigid walls that maintain the same shape when filled or drained, and regardless of the volume of the stored contents. Such arrangements can also provide a more consistent ratio of surface area to volume for the fluid in the container than bags or other flexible storage containers. Advantageously, such arrangements can provide greater predictability and reliability during freezing and thawing cycles, which can help promote cell viability.
Additionally, rigid containers can be less prone to leakage than bags and, therefore, may be more preferred for situations when the contents being stored are toxic or hazardous. One or more inner surfaces of the walls of the container (e.g., the inner surfaces of the first and second walls), may be hydrophobic. Advantageously, such an arrangement can reduce cell adhesion.
A nucleation site for ice crystal formation may be included on an inner surface of a wall defining the chamber. For example, the inner surface may include a coating with an ice nucleating agent (INA). Such coatings may be protected by a water permeable top layer (e.g., titanium carbide, molybdenum disulfide with tungsten chalcogenides, and/or boron nitride with graphyne). By “seeding” the ice formation, random formation of ice in the liquid during freezing can be reduced and/or eliminated, thus increasing sample survival rates. Random ice formation can occur at unpredictable temperatures; consequently, sample survival rates can be highly variable between repeated trials with the same freezing protocol. Furthermore, the extremely rapid crystallization which results when ice forms in a highly supercooled solution can cause damage to cells and tissues. A nucleation site provides control and increases consistency of freezing profile across samples and batches.
Advantageously, the arrangements disclosed herein can provide a cryostorage container having a chamber with a constant surface area per volume ratio along the length, width, and/or height of the chamber. For example, the chamber may have a volume defined by wall portions of the cryostorage container and wherein the wall portions of the cryostorage container each have an interior surface facing the chamber and an exterior surface opposing the interior surface and wherein each interior surface has a surface area and
wherein a ratio of the sum of the surface areas to the volume of the chamber is at or between 1 to 5 and 2 to 5.
Containers of the present disclosure can also exhibit greater compressive strength than linear containers having the same wall thickness. Advantageously, the serpentine path of the side walls of the container increase the compressive strength of the structure in at least one direction relative to a linear-wall container.
Walls of the containers may include one or more thermocouples. The thermocouple(s) may be embedded in the wall. In some embodiments, one or more walls of the containers may include one or more mounting features to facilitate consistent and reliable coupling of thermocouples to the containers. The thermocouple(s) may be separated from the sample so as to not disturb nucleation behavior.
Containers may include electrodes arranged to apply high electric fields, in the kilovolt range, for electrofreezing and/or electroporation purposes. Such electrodes may be coupled to one or more walls of the container.
Containers may include a displacement body that protrudes into the chamber of the container (e.g., the serpentine chamber). For example, one or more fins or rods may extend into the chamber and displace a volume of sample therein. Advantageously, such arrangements may further reduce the distance between a portion of the sample and a surface of the container. The displacement body/bodies may be arranged to remove heat from a sample. For example, the displacement body/bodies may have thermal conductivity greater than that of walls of the container. As one particular example, the displacement body/bodies may comprise a metal and the container walls may comprise plastic. A thermocouple may also extend into the sample volume defined by the container walls.
Containers may include identifications tags. Such tags may include electronics for the remote detection of the container and/or transfer of information therefrom (e.g., RFID, Bluetooth, etc.). Containers may include graduation marks indicative of the volume of a sample in the chamber when the container is in a particular orientation.
Containers may be optically clear, or otherwise include structures, characteristics, and/or materials, to facilitate visual inspection, optical quantitative measurement, and other types of non-destructive testing of the stored contents (for example, spectroscopy, counting, fluorescence, and the like). In some embodiments, containers include cuvette like optical characteristics.
Methods of using the containers disclosed herein include removing of oxygen from the chamber and/or purging the chamber with nitrogen gas through one or more openings. Electrical, mechanical, optical, and/or acoustical measuring of liquid level through one or more openings. Introducing INAs, sensors (e.g., optical and/or electrical such as a thermocouple), cryoprotectants, and/or cells into the chamber through one or more openings. Placing the container in a cryogenic freezer and/or placing the container in a cryopreserved cell thawer, such as the VIA Thaw CB1000 by GE Lifesciences.
The container disclosed herein may be hermetically sealed with cells and/or cryoprotectant positioned in the chamber. The containers disclosed herein may be provided in a sealed, sterile package.
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It should nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates. One embodiment of the invention is shown in great detail, although it will be apparent to those skilled in the relevant art that some features that are not relevant to the present invention may not be shown for the sake of clarity.
The language used in the claims and the written description is to only have its plain and ordinary meaning, except for terms explicitly defined below. Such plain and ordinary meaning is defined here as inclusive of all consistent dictionary definitions from the most recently published (on the filing date of this document) general purpose Merriam-Webster dictionary.
The terms “fill”, “filling”, and “filled” as used herein include both partial and complete filling. The term “drain”, “draining”, and “drained” as used herein include both partial and complete draining. The term “vent” as used herein means an opening to allow equalization of gas pressure between the inside and outside of the cryostorage container. Vents may allow the passage of gas through the vent (e.g., through a filter) and/or include a flexible membrane (e.g., a bag and/or balloon) that allows for expansion and/or contraction of gas within the chamber of the cryostorage container. The term “chamber width” as used herein means the distance between inside surfaces on opposing sides of the chamber, measured along a vector normal (i.e., perpendicular) to at least one of the inside surfaces. The “tubes”, “tubing” and “flexible tubing” disclosed herein can comprise a material suitable for cryostorage at −196° C. or below. Further forms, objects, features, aspects, benefits, advantages, and embodiments of the present invention will become apparent from a detailed description and drawings provided herewith
With respect to the specification and claims, it should be noted that the singular forms “a”, “an”, “the”, and the like include plural referents unless expressly discussed otherwise. As an illustration, references to “a device” or “the device” include one or more of such devices and equivalents thereof. It also should be noted that directional terms, such as “up”, “down”, “top”, “bottom”, and the like, are used herein solely for the convenience of the reader in order to aid in the reader's understanding of the illustrated embodiments, and it is not the intent that the use of these directional terms in any manner limit the described, illustrated, and/or claimed features to a specific direction and/or orientation.
The terms “approximately” and “about”, when qualifying a quantity, size, or geometry, shall mean the given value with a tolerance plus or minus 10 percent of the value, unless otherwise specified.
All ranges disclosed herein, unless otherwise indicated, encompass any and all sub-ranges subsumed therein. For example, a range of “less than 10” can include any and all sub-ranges between (and including) the minimum value of zero and the maximum value of 10, that is, any and all sub-ranges having a minimum value of equal to or greater than zero and a maximum value of equal to or less than 10, e.g., 1 to 5. In certain cases, the numerical values as stated for the parameter can take on negative values. In this case, the example value of range stated as “less than 10” can assume negative values, e.g. −1, −2, −3, −10, −20, −30, etc.
The first wall 120, the second wall 124, and the chamber 110 follow a serpentine path along a length L of the body 102. Each of the first wall 120 and the second wall 124 include a plurality of wall portions positioned at differing angles with respect to each other, or at alternating angles moving from the first end 132 to the second end 136. Along the serpentine path, the first wall 120 and the second wall 124 have a uniform characteristic dimension therebetween, which is a uniform distance 156 therebetween, as measured along a direction perpendicular to an inside surface 150 of the first wall 120. The uniform distance 156 is uniform across a planar cross-section parallel with the distance D. For example, the distance 156 between the second wall 124 and the first wall 120, as measured along a vector normal to the inside surface 150 of the first wall 120, can be at or between 5 mm and 7 mm. The first wall 120 can be parallel to the second wall 124 along the serpentine path.
The first wall 120 and the second wall 124 can also have the uniform distance 156 between them along the height of the body. Accordingly, the first wall 120 and the second wall 124 can be separated by the uniform distance 156 across the length L and/or the height H. Advantageously, having the uniform characteristic dimension between the first wall 120 and the second wall 124 along the length L and/or the height H of the body 102, wherein the value of the uniform characteristic dimension is relatively small, aids in maintaining a substantially uniform freeze profile along the length L and/or the height H of the body 102.
In practicality, an exact uniformity of the uniform characteristic dimension is difficult to manufacture, so some tolerance is acceptable. Further, in some embodiments, an indentation, recess, protrusion, or other nonuniform structural feature can be useful or necessary, for example, to facilitate manufacturing. These nonuniform structural features can affect the uniform characteristic dimension over a portion of a wall of the chamber 110. Accordingly, in some embodiments, the uniform characteristic dimension can range, e.g., within 0.01 mm, 0.1 mm, 0.5 mm, 1.0 mm, or 2.0 mm. In some embodiments, the uniform characteristic dimension can range, for example, to deviate 0.1%, 0.5%, 1%, 2%, 5%, 10%, 20%, or 25% from the uniform characteristic dimension's target value or median value. Generally, higher uniformity of the uniform characteristic dimension is desirable to increase uniform cooling and/or thawing rates of the contained biological samples/materials.
In some embodiment, the uniform characteristic dimension can be uniform, within any of the ranges of the above-described tolerances, for 90% or more, 95% or more, or 99% or more of the perpendicular distances between the first wall 120 and the second wall 124.
In some embodiments, the walls can slightly diverge from one another along a direction extending from a bottom 140 of the body 102 to a top 160 of the body 102. This divergence can facilitate releasing the body 102 from a mold during manufacturing while having no significant impact on varying the freeze profile along the height H of the body 102.
Advantageously, serpentine chambers having a width between inner walls, a height, and an overall length can provide a greater volume for liquid storage than linear chambers of the same width, height, and overall length. Accordingly, serpentine chambers arranged for a cryostorage box can store more liquid than a linear container of similar dimensions (that is, having equal overall lengths).
The thermal resistance of the first wall 120 and the second wall 124 is preferably uniform along the length L and height H. For example, the first wall 120 and/or the second wall 124 can have a uniform material thickness along the length L and the height H. The first wall 120 and the second wall 124 can have the same thermal resistance to promote uniform thermal transfer during freeze/thaw cycles.
Referring additionally to
Referring to
One or more of the openings 202, 204, 206 can be arranged for filling and/or draining liquid from the chamber 110. In some embodiments, one or more of the openings 202, 204, 206 can be high throughput fill ports. In some embodiments, at least one of openings 202, 204, 206 communicating with the chamber 110 can be arranged to vent air into and/or out of the chamber 110. For example, when liquid is being drained from the chamber 110, a vent opening arranged to vent air allows air to enter the chamber 110 and when liquid is being filled into the chamber 110, the vent opening allows air to exit the chamber 110. In the illustrated embodiments, the first opening 202 at the first end of the chamber 110 is arranged for venting, the second opening 204 at the second end of the chamber is arranged for draining, and the third opening 206 is arranged for filling the chamber with liquid.
In some embodiments, the cryostorage container 100 can include a lid.
A bottom side 302 of the lid 300 may include a wall 310 extending between the vent opening (e.g., first opening 202) and the fill opening (e.g., third opening 206). The wall 310 prevents fluid entering through the fill opening from being immediately drawn out the vent opening, particularly when a negative pressure is applied to the vent opening to draw gas out the chamber 110.
Referring to
The cryostorage container can include a hanging element 230, which can be a loop, as shown in
The cryostorage container 100 can be arranged to support itself on a level surface in various positions. For example, the cryostorage container 100 can be arranged to support itself in a filling configuration.
To support itself in one or more configurations (e.g., filling and/or draining configurations), the cryostorage container 100 can include one or more stands. For example, referring to
In some embodiments, the cryostorage container 100 can have a height of about 80 mm, a length of about 125 mm, a width of about 20 mm, and a volume of about 48 ml. In some embodiments, the cryostorage container 100 has a volume in a range of 100 ml to 250 ml.
As described briefly above, cryopreservation containers with relatively large capacities according to the present invention are provided with uniform characteristic dimensions and high dimensional aspect ratios to facilitate consistency and uniformity of freeze/thaw rates. Such containers can have serpentine chambers, such as the cryostorage container 100 described above. Alternatively, such containers can have other shapes. Several exemplary shapes of chambers of such containers are illustrated in
Referring now to
Surface areas of the chamber 400 relate to the aspect ratios as follows:
For relatively high aspect ratios, or relatively high ratios of SA1 to SA2 or SA1 to SA3, the characteristic dimension R significantly affects, and provides substantial consistency of, the freeze profile of the chamber 400. Such relatively high aspect ratios may be, for example, between 1 to 1 and 2 to 1, preferably between 2 to 1 and 5 to 1, and more preferably between to 1 and 20 to 1.
Referring to
Surface areas of the chamber 500 relate to the aspect ratios as follows:
For a relatively high aspect ratio, or a relatively high ratios of SA1 to SA2, the characteristic dimension R significantly affects, and provides substantial consistency of, the freeze profile of the chamber 500. Such a relatively high aspect ratio may be, for example, between 1 to 1 and 2 to 1, preferably between 2 to 1 and 5 to 1, and more preferably between to 1 and 20 to 1.
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Illustratively, the upper wall 1702 includes one recess 1706 and the lower wall 1704 includes two recesses 1708. In some embodiments, the upper wall 1702 and the lower wall 1704 define an optical path length 1710 therebetween, and the optical path length 1710 may be uniform across a set of containers of various volumes. The one recess 1706 and the two recesses 1708 can be deep enough to fulfill their intended purpose of reducing or preventing damage to the walls 1702, 1704 while also being shallow enough to maintain sufficient uniformity of the uniform characteristic dimension D1 (e.g., within the tolerances discussed above) and sufficient consistency/uniformity of the freeze/thaw rates in the chamber.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes, equivalents, and modifications that come within the spirit of the inventions defined by following claims are desired to be protected. All publications, patents, and patent applications cited in this specification are herein incorporated by reference as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated by reference and set forth in its entirety herein.
This application claims one or more inventions which were disclosed in U.S. Provisional Patent Application No. 63/307,614, filed Feb. 7, 2022, titled “Cryogenic Storage Container”. The benefit under 35 USC § 119(e) of this United States provisional application is hereby claimed, and the aforementioned application is hereby incorporated herein by reference.
Number | Date | Country | |
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63307614 | Feb 2022 | US |