Containers for cryopreserved samples

Abstract

A container (100) for cryopreserved biological samples (102) is disclosed, comprising a cavity (108) for receiving at least one cryopreserved biological sample (102) and a sealed reservoir (106) at least partially enclosing the cavity, the sealed reservoir containing a liquefied gas (120), such as liquefied air, which is maintained generally liquefied using a heat transfer engine (112), such as a Stirling refrigerator. A valve (114) may be provided to function as both a pressure relief valve and an inlet valve. The inlet valve may be coupled to a sensor (122) for sensing the volume of the liquefied gas in the sealed reservoir. The container may further comprise a heat exchanger (116) coupled to the heat engine and extending into the sealed reservoir.

Description

[Technical Field]

[0001] The present invention relates to a container for cryopreserved samples, e.g., biological samples, that allows the cryopreserved samples to be maintained for extended periods of time, e.g., months, after arrival at their destination, and that can potentially be used for controlled rates of freezing and thawing. The containers of the present invention may also be used to ship other types of samples requiring cryopreservation without the use of traditional freezing materials such as liquid nitrogen or solid carbon dioxide. [Background technology]

[0002] Cryopreservation is a technique used for the preservation of biological samples that involves cooling samples to very low temperatures, e.g., −78.5°C to −196°C, and maintaining those samples at those very low temperatures for extended periods of time. By cooling biological samples to low temperatures, the kinetics of chemical or enzymatic reactions that would otherwise degrade the sample are slowed to such an extent that the sample no longer degrades, or degrades only at a very slow rate. As a result, biological samples can be stored for extended periods of time and returned to ambient temperature when needed for use and / or analysis.

[0003] Cryopreserved samples can be transported if their temperature is maintained at a sufficiently low temperature during transport. If the sample is allowed to warm above a certain temperature, such as above the sample's glass transition point, the sample's integrity may be lost. This is because the cryoprotectants used in the cryopreservation process are somewhat toxic to the sample, potentially leading to more diffusion and therefore more chemical reactions that can affect the viability of the preserved cells. Prolonged exposure to the cryoprotectant, chemical reactions at higher temperatures, and their cumulative effects can harm cryopreserved materials. Below the glass transition point, the viscosity of the system means that the cumulative effects are very small. During cryopreservation, cooling of cells from ambient temperature must be carried out in a controlled manner to minimize harm and optimize cell viability after thawing. Therefore, to ensure sample integrity during shipping, cryopreserved samples must be kept cold enough so that the cumulative harmful effects are not significant over the expected duration of transport and storage.

[0004] In addition to the need to maintain an appropriately low temperature during transport, the shipping container and its contents must be compatible with the environments they will pass through before, during, and after transport. Therefore, for air transport, the use of phase-change coolants, such as liquid nitrogen, is unacceptable from a safety standpoint if there is a risk of liquid nitrogen spillage. To circumvent this problem, dewars with porous materials, such as dry shippers, molecular sieves, or zeolites, have been developed to ensure that cryogenic shipping can be achieved without the risk of liquid nitrogen spillage. In such dewars, the liquid nitrogen is absorbed into the porous material and retained there until it boils off and exits as gaseous nitrogen.

[0005] A problem associated with these dry shippers is that the porous material is easily contaminated, for example, with particulate biological material from the liquid nitrogen remaining in the dry shipper, and must be sterilized between each use, making its use in sterile environments such as operating rooms and clean rooms highly undesirable. Furthermore, Dewars are vacuum-lined bottles, and to ensure even pressure distribution across the bottle walls, the bottle shape must be roughly cylindrical or spherical. This is because thicker material is required to avoid catastrophic failure, thereby reducing the performance of the Dewar. The combination of these factors means that dry shippers generally take the form of a cylindrical or spherical Dewar with a relatively narrower opening at one end through which liquid nitrogen and sample are loaded. A typical dry shipper has a hole projecting radially from the central axis of the Dewar mouth. The porous material through which the liquid nitrogen is absorbed is provided in an annular shape between the outer wall of the hole and the innermost wall of the Dewar, thereby preventing the porous material (i.e., the molecular sieve element) from being easily removed and replaced in any case without first extracting the sample.

[0006] Simpler shipping containers containing a phase-change cooling material such as solid carbon dioxide as the coolant (cryoagent) can also be used to ship cryopreserved samples, consisting of an insulated bottle, e.g., a Dewar or insulated box, containing the sample on top of or immersed in a layer of solid carbon dioxide. The problem with such containers is that they can only maintain samples at low temperatures for relatively modest periods of time and are unsuitable for shipping or storage over long timescales without frequent refilling with the phase-change cooling material. Solid carbon dioxide has a temperature of approximately −78.5°C, above the glass transition point of many cryoprotectants, and this temperature may not be low enough to prevent harm to the sample before, during, or after transport over longer timescales (several days). Summary of the Invention [Problem to be solved by the invention]

[0007] Advances in medicine mean an increasing need to ship and maintain cryopreserved samples in environments where refrigerated materials (e.g., liquid nitrogen, solid carbon dioxide) and storage facilities are not available and / or practical. For example, the field of immunotherapy is rapidly developing and has considerable therapeutic potential, e.g., in the treatment of cancers such as leukemia and melanoma. In one approach, T cells are collected from a patient's blood and then genetically engineered to incorporate a chimeric antigen receptor (CAR) on their surface. The resulting chimeric antigen receptor T cells (CAR T cells) are then grown in a laboratory to provide sufficient numbers for therapy and then infused back into the patient. The CAR T cells are then able to recognize relevant protein antigens on the surface of tumor cells and further enhance the patient's immune system to kill those tumor cells. This process requires the transport of blood and / or tissue samples to a laboratory where the genetic engineering can be performed to grow the required number of CAR T cells. The CAR T cells must then be shipped back to the patient's clinic and stored until the patient is ready for treatment. This typically requires storage of the cryopreserved CAR T cell samples at the clinic for periods of several weeks or longer, which requires either the construction of an on-site cryopreservation facility or the provision of a shipping container that can also serve as a storage unit upon arrival. It is an object of the present invention to provide such a shipping container. [Means for solving the problem]

[0008] In a first aspect of the present invention, there is provided a container for cryopreserved biological samples, the container comprising an insulated housing comprising a cavity for containing at least one cryopreserved biological sample, and a sealed reservoir at least partially surrounding the cavity in the housing and containing a liquefied gas.

[0009] In a second aspect of the present invention, there is provided a method of monitoring the volume of liquefied gas in a container of the type described herein, the method comprising the steps of determining whether at least one sensor indicates that the volume of liquefied gas is less than a required volume and / or that evaporated liquefied gas is flowing out of a sealed reservoir, and sending a control signal to switch on a heat engine to condense the evaporated liquefied gas in the sealed reservoir of the container.

[0010] In a third aspect of the present invention, there is provided a method of monitoring the integrity of a vessel of the type described herein, comprising the steps of determining whether a measured power consumption of a heat engine of the vessel exceeds a predicted power consumption, and if the measured power consumption exceeds the predicted power consumption, outputting a report on the integrity of the vessel in response to the determination.

[0011] According to a related aspect of the invention, there is provided a non-transitory data carrier carrying code which, when implemented in a processor, causes the processor to perform any of the methods described herein.

[0012] As will be appreciated by those skilled in the art, embodiments of the present technology may be embodied as a system, method, or computer program product, and thus may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects.

[0013] Furthermore, embodiments of the present technology may take the form of a computer program product embodied in a computer-readable medium having a computer-readable program embodied therein. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof.

[0014] Computer program code for carrying out operations of the present technology may be written in any combination of one or more programming languages, including object-oriented and conventional procedural programming languages. Code elements may be embodied as procedures, methods, etc. and may include subelements that may take the form of instructions or sequences of instructions at any level of abstraction, from direct machine instructions to native instructions set forth in higher-level compiled or interpreted language constructs.

[0015] The technique is illustrated diagrammatically, by way of example, in the accompanying drawings. [Brief explanation of the drawings]

[0016] [Figure 1A] FIG. 1 is a schematic diagram of a container for cryopreserved samples. [Figure 1B] FIG. 1B is a schematic diagram of the airflow mechanism of the container of FIG. 1A. [Figure 2] 1B is a flow diagram of example steps for monitoring the volume of liquefied gas in the vessel of FIG. 1A. [Figure 3] 1B is a flow diagram of example steps for monitoring fluid flow from the vessel of FIG. 1A. [Figure 4] 1B is a flow diagram of example steps for monitoring the integrity of the container of FIG. 1A. DETAILED DESCRIPTION OF THE INVENTION

[0017] Many types of biological materials are cryopreserved for later use in medicine, biotechnology, and veterinary medicine. Maintaining samples at temperatures below 150 K is considered essential to ensure long-term viability. The traditional method for achieving such low temperatures is through the use of liquid nitrogen (which has a boiling point of 77 K). Following the addition of cryoprotective additives and controlled-rate freezing, the sample in a specialized cryocontainer is immersed in either liquid nitrogen, usually contained in a Dewar, or the vapor phase above the liquid nitrogen. The liquid nitrogen evaporates and is replenished with fresh liquid nitrogen, which can be done manually or by an automated top-up system from a larger Dewar or storage tank. As an alternative to liquid nitrogen, mechanical freezers operating at 120 K have been developed.

[0018] However, current cryopreservation methods present several problems. For example, liquid nitrogen is expensive and can be difficult to obtain in some geographic locations. Health and safety issues can arise associated with storing and handling large quantities of liquid nitrogen. Furthermore, after production, liquid nitrogen may contain very low levels of contaminants, and further contamination can occur during transportation and storage. Therefore, liquid nitrogen must always be considered contaminated with viable microorganisms. Contamination of liquid nitrogen by ice, inanimate tissue fragments, and viable microorganisms has been documented, and several reports of contaminant transfer from liquid nitrogen to its vapor have been documented. While it is possible in principle to filter liquid nitrogen, this can require specialized equipment and may require verification of the filtration process each time it is performed to prove that contaminants have been removed. If verification is not possible, liquid nitrogen cannot be used in clean rooms without compromising air quality. Furthermore, to achieve cryogenic temperatures, mechanical freezers traditionally employ cascade compressors, which tend to be large, noisy, and expensive.

[0019] Broadly speaking, the present technology relates to a container for cryopreserved biological samples that includes a supply of liquefied gas for maintaining the cryopreserved biological sample at a required temperature while the sample is being stored and / or shipped. The containers described herein include a sealed reservoir containing at least the liquefied gas used to maintain the cryopreserved biological sample at a required temperature, although the liquefied gas does not directly contact the sample. Evaporation of the liquefied gas in the sealed reservoir can be mitigated by providing a means within the container for condensing the evaporated liquefied gas, thereby maintaining the liquefied gas in the sealed reservoir at a volume required to maintain the sample within the container at the required temperature. Embodiments of the container can advantageously eliminate or substantially reduce the possibility of the biological sample being contaminated by the liquefied gas or evaporated liquefied gas. Furthermore, providing a sealed reservoir containing the liquefied gas within the container can also allow the same supply of liquefied gas to be used for a substantially extended period of time, solving the problem of liquefied gas being unavailable in some geographic locations. Furthermore, when provided in a sealed reservoir, the same supply can be used and reused, thereby reducing health and safety concerns as users of the container do not need to come into contact with liquefied gas, particularly when placing a sample into or removing a sample from the container.

[0020] 1A shows a schematic diagram of a container 100 for storing and / or shipping a cryopreserved sample 102, where the cryopreserved sample within the container 100 is maintained at a required temperature for an extended period of time to ensure sample integrity. The cryopreserved sample 102 may be a cryopreserved biological sample or any type of sample that requires low-temperature storage without the use of traditional freezing materials such as liquid nitrogen or solid carbon dioxide.

[0021] Container 100 comprises an insulated housing with a cavity 108 for containing at least one cryopreserved biological sample 102, and a sealed reservoir 106 at least partially enclosing housing cavity 108. In embodiments, sealed reservoir 106 may comprise liquefied gas 120 provided in the sealed reservoir from at least one external source (not shown). Liquefied gas 120 may be any one or more of liquefied helium, liquefied nitrogen, liquefied air, and liquefied oxygen, although it will be understood that this is a non-exclusive and non-limiting list of suitable materials. Additionally or alternatively, sealed reservoir 106 may comprise liquefied gas absorbed in a suitable material.

[0022] The sealed reservoir 106 includes at least one valve 114. The at least one valve 114 may be a relief valve, a pressure relief valve, or a safety valve for controlling or limiting the pressure within the sealed reservoir 106. The relief valve may be designed to open automatically when a predetermined pressure is reached within the sealed reservoir 106. The relief valve may be included in the event of failure of the mechanism within the container for condensing / re-liquefying evaporated liquefied gas (which may result in a buildup of gas within the sealed reservoir 106), a loss of power to this mechanism, or a failure of the insulation of the container 100.

[0023] In an embodiment, at least one valve 114 may be or include a flow sensor. The flow sensor may be used to determine whether gas is entering or leaving the sealed reservoir 106. For example, if it is determined that gas is leaving the sealed reservoir 106, this may indicate a leak due to a pressure relief being activated or that there is a leak that may be allowing gas to escape from the sealed reservoir 106 (which may mean that the supply of liquefied gas 120 needs to be replenished more frequently). The flow sensor (not shown in FIG. 1A ) may be coupled to a controller such that if the flow sensor indicates that gas is escaping the sealed reservoir, the controller can take action to correct this situation. For example, the controller may turn on a refrigerator to cool / condense the gas, thereby reducing or stopping the flow of gas out of the sealed reservoir 106. This is described in more detail below.

[0024] The at least one valve 114 may be an inlet valve for filling the sealed reservoir 106 with gas (to be condensed in the reservoir to provide a liquefied gas) or liquefied gas 120. Accordingly, the inlet valve may be connectable to an external source of gas / liquefied gas 120 so that the gas / liquefied gas can flow into the sealed reservoir 106. In an embodiment, the inlet valve may be connected to at least one sensor 122 in the sealed reservoir 106. The at least one sensor 122 may be a sensor for sensing the volume of liquefied gas 120 in the sealed reservoir 106. The inlet valve 114 may be configured to automatically close when the at least one sensor 122 indicates that the desired volume of liquefied gas 120 is available in the sealed reservoir 106. In an embodiment, the sealed reservoir 106 may have at least two "fill sensors" 122, one that can be used to determine whether a minimum desired volume of liquefied gas 120 is present in the sealed reservoir 106, and another that can be used to determine whether a maximum volume of liquefied gas 120 is present in the sealed reservoir 106. In such an embodiment, the inlet valve 114 may remain open until the sensor indicates that the maximum volume of liquefied gas 120 has been reached.

[0025] In embodiments, liquefied air may be used in the sealed reservoir 106 to maintain the sample 102 in the cavity 108 at the required cooling temperature. Liquefied air is air that has been cooled to a very low temperature so that it condenses into a liquid. Air from the external environment is pumped into the sealed reservoir 106 of the container 100 and cooled to form liquefied air. Air and liquefied gases typically include nitrogen, oxygen, argon, and other inert gases. Using air or liquefied gas as a means for providing cooling to the sample 102 may be advantageous because a separate, dedicated supply of gas / liquid does not need to be provided to the container 100 (e.g., a canister of liquid nitrogen). Instead, air from the environment surrounding the container 100 may be pumped into the container and cooled (condensed) to a cryogenic temperature. This may reduce the operating costs of the container 100.

[0026] However, problems can arise when the liquefied air warms and begins to evaporate. The boiling point of liquid air is between that of liquid nitrogen and that of liquid nitrogen. As a result, as the liquid air boils and evaporates (e.g., because the mechanism for cooling / condensing the air is switched off), the nitrogen component evaporates more quickly than the oxygen component of the liquid air. This can result in a liquid-air mixture containing up to approximately 50% oxygen. Liquid oxygen contains 4,000 times more oxygen by volume than regular air, and materials typically considered non-flammable (such as carbon in powder form, stainless steel, and aluminum) can burn in the presence of liquid oxygen. Therefore, it may be desirable to reduce, minimize, or eliminate the accumulation of liquid oxygen within the container.

[0027] Thus, in embodiments, at least one valve 114 may be coupled to an airflow mechanism for reducing or eliminating liquid oxygen and frost buildup within the container 100. An example airflow mechanism is shown in FIG. 1B. The airflow mechanism can allow gas to flow into the sealed reservoir 106 of the container 100 and allow gas (e.g., evaporated, and therefore warm, liquefied gas) to flow from the sealed reservoir 106. The airflow mechanism can include a tube 124 connectable to the valve 114. The tube 124 can be branched or shaped into a first branch and a second branch, as shown in FIG. 1B. An inlet is provided in the first branch of the tube 124 to allow gas (e.g., air from the external environment) to flow into the sealed reservoir 106 of the container 100. A one-way valve 126 is provided along the first branch to prevent evaporated air from within the sealed reservoir from flowing along the first branch and affecting the functionality of the inlet. An outlet is provided in the second branch of the tube 124 to allow gas (including evaporated liquefied gas) to flow out of the sealed reservoir 106. A one-way valve 128 is provided along the second branch of the tube 124 that is capable of preventing gas from outside the container 100 from flowing through the second branch into the sealed reservoir.

[0028] In embodiments, to reduce the accumulation of liquid oxygen in the sealed reservoir 106, the airflow mechanism may include a chamber 130 located between the inlet and the one-way valve 126 in the first branch of the tube 124. The chamber 130 may contain an oxygen scavenger. An oxygen scavenger or oxygen absorber is a material that helps remove or reduce oxygen levels. The oxygen scavenger may be an iron-based oxygen scavenger or a non-ferrous oxygen scavenger. Thus, oxygen from the gas (e.g., air) flowing into the inlet of the tube 124 can be at least partially removed, which reduces the potential accumulation of liquid oxygen when the gas condenses in the sealed reservoir 106. In embodiments, the chamber 130 may be removably mounted in the first branch of the tube 124. This allows the entire chamber 130 to be removed so that the oxygen scavenger can be discarded and replaced with new oxygen scavenging material. In embodiments, the entire chamber 130 may be discarded and replaced with a new chamber 130 containing new oxygen scavenging material. Additionally or alternatively, chamber 130 may be openable in situ to allow the oxygen scavenger to be removed and replaced with new material.

[0029] In embodiments, to reduce frost buildup in the sealed reservoir 106 (which may reduce the cooling potential of the condensed gas), the airflow mechanism may include a chamber 132 located in the first branch of the tube 124. If chamber 130 is not provided, chamber 132 is located between the inlet and one-way valve 126 in the first branch of the tube 124. If chamber 130 is also present, chamber 132 is located in the first branch of the tube 124 between chamber 130 and one-way valve 126, i.e., after the chamber containing the oxygen scavenging material. Chamber 132 contains a desiccant or other suitable material for absorbing moisture / water from the input gas. Removing moisture / water from the input air reduces the likelihood of frost or ice forming in the container 100, and particularly in the sealed reservoir 106. Frost or ice may reduce the efficiency of the cooling provided by the condensed gas by inhibiting thermal energy transfer between the sealed reservoir 106 and the cavity 108. Chamber 132 may be removably mounted on the first branch of tube 124. This allows the entire chamber 132 to be removed so that the desiccant can be discarded and replaced with new desiccant. In embodiments, the entire chamber 132 may be discarded and replaced with a new chamber 132 containing new desiccant. Additionally or alternatively, chamber 132 may be openable in situ to allow the desiccant to be removed and replaced with new material.

[0030] In an embodiment, a single valve 114 may be capable of functioning as both a pressure relief valve and an inlet valve.

[0031] Thus, in embodiments, at least one valve 114 is an inlet valve for filling the sealed reservoir with gas or liquefied gas. The inlet valve may be connectable to an airflow mechanism to allow gas to flow into the sealed reservoir (where it may be condensed to provide liquefied gas) and to allow evaporated gas to flow from the sealed reservoir. The airflow mechanism may include at least one chamber located between the gas inlet and the inlet valve. The at least one chamber may contain an oxygen absorber or desiccant. In embodiments, a flow sensor may be provided in the inlet valve to detect fluid flow into and / or out of the sealed reservoir, specifically to detect the flow of evaporated liquefied gas out of the reservoir.

[0032] Vessel 100 may include a heat engine 112 for condensing gas in sealed reservoir 106 to provide liquefied gas and / or for cooling liquefied gas 120 in sealed reservoir 106. The heat engine may be a refrigerator, a Klemenko cycle refrigerator, a pulse tube refrigerator, an "acoustic Stirling" refrigerator, a Joule-Thomson refrigerator, a Stirling refrigerator (also known as a Stirling engine), or any other suitable means of cooling. In an embodiment, the heat engine may be a Stirling refrigerator having a cooling capacity of at least 20 W at 77 K. Heat engine 112 may be used to condense / re-liquefy evaporated liquefied gas in sealed reservoir 106 to maintain the height / volume of cryogen within vessel 100.

[0033] The vessel 100 may include a heat exchanger 116 coupled to the heat engine 112. The heat exchanger 116 may extend into the sealed reservoir 106 to provide cooling to the liquefied gas 120, as shown in FIG. 1A. The heat exchanger 116 may thus be able to extract heat from the top of the sealed reservoir 106 to cool the liquefied gas 120 and to condense evaporated liquefied gas 120 that may rise to the top of the sealed reservoir 106. Arrows 118 indicate the direction of flow of condensed water that is formed when the heat engine 112 and the heat exchanger 116 are switched on.

[0034] As the liquefied gas in the sealed reservoir 106 evaporates, the evaporated liquefied gas rises to the top of the sealed reservoir 106 where it can be in proximity to a heat exchanger 116 coupled to a heat engine 112. The heat engine 112 can operate at a temperature below the saturation temperature at the pressure of the liquefied gas in the sealed reservoir 106 (e.g., 77 K for liquefaction at 1 bar for liquid nitrogen) to achieve liquefaction / condensation of the evaporated liquefied gas. When not being used to liquefy gas, the heat engine 112 can be used to lower the temperature of the liquefied gas in the sealed reservoir 106, thereby reducing evaporation.

[0035] As previously mentioned, the container 100 may include at least one sensor 122 within the sealed reservoir 106 for sensing the volume or height of the liquefied gas 120 within the sealed reservoir 106. It is understood that the location of the sensor 122 in Figure 1A is exemplary and non-limiting.

[0036] The vessel 100 may include at least one controller (not shown in FIG. 1A ) coupled to the at least one sensor 122. The controller may be configured to determine whether the at least one sensor 122 indicates that the volume of the liquefied gas 120 is less than the requested volume and to send a control signal to the heat engine 112 to switch on the heat engine, thereby condensing the evaporated liquefied gas in the sealed reservoir 106.

[0037] As previously mentioned, at least one valve 114 may be or may include a flow sensor capable of detecting gas flow into and / or out of the sealed reservoir 106. The flow sensor may be coupled to a controller such that, if it indicates that gas is escaping the sealed reservoir, the controller can take action to correct the situation. For example, the controller may signal the heat engine 112 to switch on and cool / condense the gas, thereby reducing or stopping the flow of gas out of the sealed reservoir 106. The controller may signal the heat engine 112 to switch off when the flow sensor indicates that the flow of gas out of the sealed reservoir 106 has significantly reduced or stopped, which may indicate re-condensation of the evaporated liquefied gas in the sealed reservoir 106. The flow sensor may be able to provide the controller with a faster response than the height / volume sensor 122.

[0038] In an embodiment, the controller may be further configured to determine whether the at least one sensor 122 indicates that the volume of the liquefied gas 120 is less than the requested volume after a specific time, and to send a control signal to the heat engine 112 to switch the heat engine off, and, in response to the preceding determination, to output a message indicating that liquefied gas needs to be added to the sealed reservoir 106. The specific time may be the time after which the requested volume is predicted to be reached. This may be determined from experimentation / calibration of the container 100. In an embodiment, the controller may be able to determine from data from the at least one sensor 122 how much volume deficit there is in the sealed reservoir 106 (i.e., the difference between the requested volume and the sensed volume) and how long the heat engine 112 must be switched on to reach the requested volume. This may determine a specific time after which the sensors may be polled again.

[0039] In an embodiment, the container 100 may be equipped with a power meter (not shown in FIG. 1A ) for measuring the power consumption of the heat engine 112 when it is switched on / used to cool the sealed reservoir 106.

[0040] The aforementioned controller, or an additional controller, may be coupled to the power meter. The controller may be configured to determine whether the measured power consumption of the heat engine 112 exceeds the predicted power consumption, and if the measured power consumption exceeds the predicted power consumption, output a report on the integrity of the vessel 100 in response to the previous determination. In this manner, the integrity of the vessel 100 may be determined. For example, if it is determined that the heat engine 112 is using more power than predicted, the vessel 100 may not be well insulated, or there may be a leak in the sealed reservoir that is causing the liquefied gas to evaporate or leak from the vessel 100.

[0041] Container 100 may include a communications module (not shown in FIG. 1A) for communicating information to any one or more of a user of the container, a remote server, a manufacturer or supplier of the container, an electronic display device, an electronic device, etc. For example, a report on the integrity of the container and / or a message regarding topping off the reservoir with more liquefied gas may be communicated to a user or to a device / server external to container 100 so that relevant action can be taken.

[0042] The container 100 may include vacuum insulation / vacuum insulation layer 104. The vacuum insulation 104 may be provided by one or more vacuum insulation panels. As shown in FIG. 1A , the vacuum insulation surrounds the sealed reservoir 106 and the cavity 108 to prevent overheating of both the liquefied gas in the sealed reservoir 106 and the sample 102 in the cavity 108. In contrast, the sealed reservoir 106 at least partially surrounds the cavity 108 so that the cool liquefied gas can maintain the cavity 108 and the sample 102 at a required temperature.

[0043] The container 100 may be provided with a removable insulating lid or cover 110, and the housing and cavity 108 may be sealable by the removable lid 110.

[0044] The container 100 described herein can be for storing and / or shipping cryopreserved biological samples.

[0045] 2 is a flow diagram of example steps for monitoring the volume of liquefied gas in the configuration of FIG. 1A. In step S200, at least one sensor 122 is used to sense / measure the volume of liquefied gas in the sealed reservoir 106. A controller or processor (or similar component) uses the sensor data to determine whether the sensed volume of liquefied gas is less than a required volume (step S202). The required volume is the volume needed to ensure that the cavity 108 of the container 106, and therefore the sample 102, is at a required temperature to ensure sample integrity. If the sensed volume is equal to or greater than the required volume, processing returns to step S200. If the sensed volume is less than the required volume, the controller sends a control signal to switch on the heat engine 112, thereby condensing the evaporated liquefied gas in the sealed reservoir 106 and lowering the temperature in the reservoir (step S204).

[0046] After a specific time T, the controller may send a control signal to switch off the heat engine 112 (step S206). Data from the at least one sensor 122 may be read again to determine the current volume of liquefied gas in the sealed reservoir 106 (step S208). The specific time may be the time after which the requested volume is predicted to be reached. This may be determined from experimentation / calibration of the container 100. In an embodiment, the controller may be able to determine from the data from the at least one sensor 122 how much volume deficit there is in the sealed reservoir 106 (i.e., the difference between the requested volume and the sensed volume) and how long the heat engine 112 must be switched on to reach the requested volume. This may determine a specific time after which the sensor may be polled again. (As mentioned above, a flow sensor in valve 114 may be used in addition to or instead of height / volume sensor 122 to determine when heat engine 112 may need to be turned on to counteract evaporation of the liquefied gas in sealed reservoir 106. A flow sensor may provide a better and faster response than height / volume sensor 122.)

[0047] In step S210, the controller determines whether the sensed volume is still less than the requested volume. If the sensed volume is at least equal to the requested volume, processing returns to step S200. If the sensed volume is still less than the requested volume, the controller may be configured to output a message or control signal indicating that liquefied gas needs to be added to the sealed reservoir 106 (i.e., that the sealed reservoir 106 needs to be topped up with more liquefied gas from an external source) (step S212). As previously mentioned, this may be achieved by using a communications module to communicate with a user of the container or an external device / server. In an embodiment, in step 212, if liquefied gas needs to be added to the container, the controller may cause a warning light or the like to appear or sound an alarm. After the reservoir has been topped up (either with liquefied gas or with gas that condenses into the provided liquefied gas) so that the requested volume of liquefied gas is achieved, processing returns to step S200.

[0048] 3 is a flow diagram of example steps for monitoring fluid flow from the vessel of FIG. 1A, specifically, the flow of evaporated liquefied gas from the sealed reservoir 106 of the vessel 100. In step S300, a flow sensor in the valve 114 is used to detect / sense the flow of evaporated liquefied gas from the sealed reservoir 106. In response to the flow sensor data, a controller or processor (or similar component) commands the refrigerator / heat engine 112 to switch on (step S302) to cool the liquefied gas in the sealed reservoir and condense the evaporated liquefied gas within the sealed reservoir, thereby stopping or substantially reducing the flow of evaporated liquefied gas from the sealed reservoir 106.

[0049] The controller continues to either receive data from the flow sensor or periodically poll the flow sensor to determine whether gas flow from the sealed reservoir 106 has significantly reduced or stopped (step S304). If the flow sensor data indicates that gas flow from the sealed reservoir 106 (through the valve 114) has significantly reduced or stopped, the controller commands the heat engine 112 to switch off (step S306), and the process returns to step S300. However, if the flow sensor data indicates that gas continues to flow from the sealed reservoir 106 at an unacceptable rate, the controller determines whether a certain time T has elapsed since the heat engine 112 was switched on (step S308). The time T may be determined from experimentation / calibration of the vessel 100 and is the time it takes for the condensation of evaporated liquefied gas to be substantially complete. Alternatively, the time T may be the maximum time the heat engine 112 may be operated for purposes of, for example, vessel power efficiency.

[0050] If, in step S308, time T has not yet been reached, the controller continues to operate the heat engine 112 (step S310). However, if, in step S308, time T has been reached but gas is still flowing from the sealed reservoir 106, the controller may be configured to first command the heat engine 112 to switch off (step S312) and then output a message or control signal indicating that liquefied gas needs to be added to the sealed reservoir 106 (i.e., that the sealed reservoir 106 needs to be topped up with more liquefied gas from an external source) (step S314). As previously mentioned, this may be accomplished using a communications module to communicate with a user of the container or an external device / server. In an embodiment, if liquefied gas needs to be added to the container in step S314, the controller may cause a warning light or the like to appear or sound an alarm. After the reservoir has been topped up (either with gas that is condensed into the liquefied gas being provided, or with liquefied gas) so that the required volume of liquefied gas is achieved, processing returns to step S300.

[0051] In an embodiment, the method illustrated in FIG. 2 and the method illustrated in FIG. 3 may be combined.

[0052] Thus, in an embodiment, there is provided a method for monitoring the volume of liquefied gas in a container, the method comprising the steps of determining whether at least one sensor indicates that the volume of liquefied gas is less than a required volume and / or that evaporated liquefied gas is flowing out of a sealed reservoir, and sending a control signal to switch on a heat engine to condense the evaporated liquefied gas in the sealed reservoir of the container.

[0053] The method may further include determining whether the at least one sensor indicates that the volume of liquefied gas is still less than the required volume after a certain time, sending a control signal to switch off the heat engine, and outputting a message in response to the previous determination indicating that liquefied gas needs to be added to the sealed reservoir.

[0054] The method may further include determining whether, after a certain time, the at least one sensor indicates that evaporated liquefied gas is still flowing out of the sealed reservoir, sending a control signal to switch off the heat engine, and outputting a message in response to the previous determination indicating that liquefied gas needs to be added to the sealed reservoir.

[0055] FIG. 4 is a flow diagram of example steps for monitoring the integrity of the vessel of FIG. 1A. As previously mentioned, the controller may be coupled to a power meter that measures the power consumption of the heat engine 112 during operation. Thus, as step S400, the process involves measuring the power input to, or power consumed by, the heat engine 112. The controller may be configured to determine whether the measured power consumption of the heat engine 112 exceeds the predicted power consumption (step S402). If the measured power consumption is equal to or less than the predicted power consumption, the process may return to step S400. If the measured power consumption exceeds the predicted power consumption, the controller may output a report on the integrity of the vessel 100 (step S404). In this manner, the integrity of the vessel 100 may be determined. For example, if it is determined that the heat engine 112 is using more power than predicted, the vessel 100 may not be well insulated, or there may be a leak in the sealed reservoir that is causing liquefied gas to evaporate or leak from the vessel 100.

[0056] Thus, in an embodiment, a method for monitoring the integrity of a container is provided, the method including determining whether a measured power consumption of a heat engine of the container exceeds a predicted power consumption, and if the measured power consumption exceeds the predicted power consumption, outputting a report on the integrity of the container in response to the determination.

[0057] Embodiments of the present technology also provide a non-transitory data carrier bearing code which, when implemented in a processor, causes the processor to perform the methods described herein.

[0058] The present technology further provides processor control code for carrying out the aforementioned methods, for example in a general-purpose computer system or digital signal processor (DSP). The present technology also provides a carrier carrying processor control code for carrying out any of the aforementioned methods, when executed, in particular in a non-transitory data carrier, a non-transitory computer-readable medium such as a disk, microprocessor, CD-ROM, or DVD-ROM, a programmed storage device such as read-only memory (firmware), or a data carrier such as a carrier of an optical or electrical signal. The code may be provided on a (non-volatile) carrier such as a disk, microprocessor, CD-ROM, DVD-ROM, or a programmed storage device such as non-volatile storage (e.g., flash) or read-only memory (firmware). Code (and / or data) for implementing embodiments of the present technology may include source code, object code, or executable code in a conventional programming language (interpreted or compiled) such as C, or assembly code, such as code for configuring or controlling an ASIC (application-specific integrated circuit) or FPGA (field-programmable gate array), or code for a hardware description language such as Verilog™ or VHDL (Very High Speed Integrated Circuit Hardware Description Language). As those skilled in the art will appreciate, such code and / or data may be distributed among multiple coupled components in communication with each other. The present technology may comprise a controller including a microprocessor, working memory, and program memory coupled to one or more of the system's components.

[0059] Computer program code for carrying out operations for the above-described techniques may be written in any combination of one or more programming languages, including object-oriented and conventional procedural programming languages. Code elements may be embodied as procedures, methods, etc., and may include subelements that may take the form of instructions or sequences of instructions at any level of abstraction, from direct machine instructions to native instruction sets to higher-level compiled or interpreted language constructs.

[0060] It will also be apparent to those skilled in the art that all or part of the logical methods according to preferred embodiments of the present technology may be suitably embodied in a logic device including logic elements for performing the steps of the aforementioned methods, and that such logic elements may comprise components such as logic gates, for example, programmable logic arrays or application specific integrated circuits, etc. Such logical configurations may further be embodied in elements capable of temporarily or permanently establishing logic structures, for example, in arrays or circuits using a virtual hardware description language, which may be stored and transmitted using a fixed or transmissible carrier medium.

[0061] In an embodiment, the technology may be realized in the form of a data carrier carrying functional data, said functional data comprising functional computer data structures which, when loaded into and operated by a computer system or network, enable said computer system to perform all the steps of the above-described method.

[0062] Those skilled in the art will recognize that the foregoing description describes what is believed to be the best mode, and that there are other suitable modes of practicing the technology, and that the technology is not limited to the specific configurations and methods disclosed herein of the preferred embodiment. Those skilled in the art will recognize that the technology has wide application and that the embodiments are susceptible to wide variation without departing from the inventive concept as defined in the appended claims. [Explanation of symbols]

[0063] 100 containers 102 Frozen samples 104 Vacuum insulation 106 Sealed reservoir 108 Vacant Space 110 Insulated lid, cover 112 Heat Engine 114 At least one valve, inlet valve 116 Heat exchanger 120 Liquefied Gas 122 At least one sensor, fill sensor, height / volume sensor 124 tube 126, 128 One-way valve 130, 132 Chambers

Claims

1. 1. A container for cryopreserved biological samples, comprising: an insulated enclosure comprising a cavity for containing at least one cryopreserved biological sample; a sealed reservoir containing a liquefied gas at least partially surrounding the cavity of the insulated enclosure; a heat engine for condensing gas in the sealed reservoir to provide a liquefied gas or for cooling the liquefied gas in the sealed reservoir; an air flow mechanism for filling the sealed reservoir with a gas or liquefied gas, the air flow mechanism comprising a chamber located between a gas inlet and an inlet valve to the sealed reservoir; Including, the sealed reservoir comprises at least one valve, the at least one valve including a pressure relief valve; 10. The container of claim 9, wherein the inlet valve is configured to be connectable to the air flow mechanism to allow gas to flow into the sealed reservoir and to allow evaporated gas to flow out of the sealed reservoir.

2. 10. The container of claim 1, wherein the chamber contains an oxygen absorber and / or a desiccant and / or is removably mounted to the airflow mechanism.

3. 3. A container according to claim 1 or 2, wherein a flow sensor is provided to detect fluid flow into and / or out of the sealed reservoir.

4. 4. The vessel of claim 1, further comprising a heat exchanger coupled to the heat engine, the heat exchanger extending into the sealed reservoir to provide cooling to the liquefied gas.

5. further comprising at least one sensor within the sealed reservoir for sensing a volume of liquefied gas within the sealed reservoir, and a controller coupled to the at least one sensor; The control device determining whether the at least one sensor indicates that the volume of liquefied gas is less than a required volume; sending a control signal to the heat engine to switch on the heat engine to condense the evaporated liquefied gas in the sealed reservoir; Consists of The control device determining whether the at least one sensor indicates that the volume of liquefied gas is less than a required volume after a specified time; sending a control signal to the heat engine to switch off the heat engine; and and in response to said determining, outputting a message indicating that liquefied gas needs to be added to said sealed reservoir.

5. The container according to claim 1, wherein the container is configured as follows:

6. 6. The vessel of any one of claims 1 to 5, further comprising a power meter for measuring the power consumption of the heat engine when it is switched on.

7. 7. The container of claim 1, further comprising a communications module for communicating information to any one or more of a user of the container, a remote server, a manufacturer or supplier of the container, an electronic display device, or an electronic device.

8. 8. The container of any one of claims 1 to 7, further comprising vacuum insulation by one or more vacuum insulation panels.

9. 9. The container of claim 1, further comprising a removable insulating lid, wherein the insulating housing and the cavity are sealed by the removable lid.

10. 10. A method for monitoring the volume of liquefied gas in a container according to any one of claims 1 to 9, comprising the steps of: determining whether at least one sensor indicates that the volume of liquefied gas is less than the required volume and / or that evaporated liquefied gas is flowing out of said sealed reservoir; sending a control signal to switch on the heat engine to condense evaporated liquefied gas in the sealed reservoir of the container; A method comprising:

11. a) determining whether the at least one sensor indicates that the volume of liquefied gas is still less than the required volume after a certain time, or b) determining whether the at least one sensor indicates that evaporated liquefied gas is still flowing out of the sealed reservoir after a certain time; sending a control signal to switch off said heat engine; outputting a message in response to said determining that liquefied gas needs to be added to said sealed reservoir; 11. The method of claim 10, further comprising:

12. 10. A method for monitoring the status of a container according to any one of claims 1 to 9, comprising: determining whether a measured power consumption of the heat engine of the vessel exceeds a predicted power consumption; outputting a report on the status of the vessel in response to said determining if said measured power consumption exceeds predicted power consumption; A method comprising:

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