Background

[0001] Assisted reproductive techniques (ART) facilitate in infertility treatment of couples who are unable to conceive by natural means. In ART, male and female gametes (ovum and sperm) are collected from the couples which are then used for fertilization. In vitro Fertilization (IVF) is a type of ART in which male and female gametes are collected from the body of the prospective parents and are mixed together to allow fertilization in vitro, i.e., outside the body, in a culture media within a controlled environment, such as a laboratory.

[0002] Often the gametes are stored for future use or for transporting between laboratories. Further, during culture, manipulation, and insemination of the gametes they may also be stored in a controlled environment. Cryopreservation techniques may be employed for efficient storage of the collected gametes. In the cryopreservation techniques, the collected gametes may be stored temporarily in boxes, also referred to as cryoboxes, and sometimes in larger tanks for storage over longer time periods.

BRIEF DESCRIPTION OF DRAWINGS

[0003] The following detailed description references the drawings, wherein:

[0004] Fig. 1 illustrates a perspective view of a cryopreservation box, according to an example;

[0005] Fig. 2 illustrates a cross-sectional view of the cryopreservation box, according to an example; and

[0006] Fig. 3 illustrates a cross-sectional view of the cryopreservation box depicting canisters, female gametes carrier device positions, and area of the female gametes carrier device movement during the transfer into the canisters, according to an example.

DETAILED DESCRIPTION

[0007] IVF techniques involve collection of male and female gametes from bodies of the prospective parents. The female gametes called ova (eggs) are collected from the follicles of ovary of the prospective mother. The collected female gametes are either directly frozen so that they can produce optimal results on fertilization of embryos when they are frozen for future use. Vitrification refers to a cryopreservation technique that leads to a glass-like solidification upon freezing. In an example, oocytes, zygotes, embryos or blastocysts may be frozen by vitrification for cryopreservation. Vitrification is generally used for freezing the female gametes. The female gametes are held inside straws that are then immersed inside liquid nitrogen, which is at a temperature of about -196 degrees Celsius, for storing the female gametes for a longer period of time to stop the biological clock and degradation. To enable proper vitrification, the temperature of the straws containing ova or embryos shall be maintained.

[0008] Generally, the straws containing the embryos are immersed inside a liquid nitrogen tank for long term storage. However, the straws are sometimes removed from the tank for embryo/ova manipulation, such as ova sorting, embryo culture, ova screening, and analysis of embryos. The embryo/ova manipulation is generally carried out in a workbench inside an IVF laboratory which is maintained at room temperature. For manipulation, the straws are required to be removed from the tank and carried to the workbench. As the straws are moved out of the liquid nitrogen tank and transported to the workbench for manipulation, the temperature of the surroundings of the straws are subjected to change. Fluctuation of the temperature of the surroundings of the straw may cause damage to the embryos or suboptimal development of the embryos and may result in inefficient vitrification of the ova. Thus, temperature of the straws is required to be maintained while they are transported from the tank to the workbench and vice versa.

[0009] The straws after being removed from the liquid nitrogen tank are generally placed inside a transient box, such as a polystyrene or thermocol box, filled with liquid nitrogen. The liquid nitrogen in the box enables the straws to be maintained at constant temperatures of about -196 degrees Celsius, thereby reducing heat exchange between the straws and its surroundings. Hence, the box acts as an intermediate storage for transporting the straws from the tank to the workbench for thawing or transfer, whereas, from the work bench to the main storage tank after the vitrification procedure. The straws may be removed from the canisters and placed inside the box while being transported to the workbench. [0010] Inside the box, a straw is loosely placed/arranged against a wall of the box. To retrieve the straw from the box, a user/embryologist generally uses a pair of tweezers to grip the straw and pull the straw out of the box. When the user/embryologist attempts to grip the straw with the pair of tweezers, there may be chances that the straw may slip along the wall and fall inside the box. Thus, retrieval of the straw from the box is complex and time consuming. Further, since the box is filled with liquid nitrogen, fumes of liquid nitrogen may be formed over an open face of the box. The fumes may blur the vision of the user attempting to retrieve the straw thereby rendering retrieval of the straw even more cumbersome. Thus, handling and picking the straws from the box is complex and time consuming. Further, for the ova/embryo manipulation, the straws shall be moved from the box to the workbench and then back to the box during the vitrification process within a short time period to prevent the ova/embryos from being exposed to the air. Quick transfer of the straws from the box to workbench and back to the box may make retrieval of the straws from the box additionally complex.

[0011 ] Further, liquid nitrogen is filled inside the box up to a predefined level.

Since the straw is loosed placed along the inside wall of the box, the straw lies in a slanting position inside the box and a substantial portion of the straw remains below the predefined level of liquid nitrogen contained in the box. Thus, a small section of the straw remains above the level of the liquid nitrogen for being gripped by the pair of tweezers during retrieval of the straw from the box. The small section of the straw above the level of liquid nitrogen, may not allow the straw to be conveniently gripped for retrieval from the box.

[0012] The present disclosure describes a box, also referred to as a cryopreservation box, having an arrangement that enables the straws also referred to as female gametes carrier device to be held in a fixed upright position within the box. Since, the female gametes carrier device is held in the fixed upright position, storage of the female gametes carrier device inside the box and retrieval of the female gametes carrier device from the box is convenient. The cryopreservation box, also referred to as cryobox, of the present disclosure has structures to hold cannisters within which the female gametes carrier devices are kept before being moved into the larger liquid nitrogen tanks. The structures for holding the cannisters inside the box, makes the system more compact and convenient for a user to move the female gametes carrier device from a working area to the cannisters and vice versa. Also, in the cryobox of the present disclosure, reservoirs are present for monitoring the inflow of liquid nitrogen which enables efficient use and monitoring the level of liquid nitrogen.

[0013] The following detailed description refers to the accompanying drawings (drawn not to the scale). Wherever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar parts. While several examples are described in the description, modifications, adaptations, and other implementations are within the scope of providing a cryopreservation box having an arrangement that enables the female gametes carrier device to be held in a fixed upright position within the box. Accordingly, the following detailed description does not limit the disclosed examples. Instead, the proper scope of the disclosed examples may be defined by the appended claims.

[0014] Fig. 1 illustrates a perspective view of a cryopreservation box 100, according to an example. As shown, the cryopreservation box 100, also referred to as a cryobox 100, includes a base surface 102, a first wall 104, a second wall 106, a third wall 108, and a fourth wall 1 10, In an example, the cryopreservation box 100 may be of a rectangular or square shape. The cryopreservation box 100 may be made up of polystyrene material in an example, each of the first, second, third and fourth walls has a thickness ranging from about 2 centimeters (cm) to about 5 cm. Further, in an example, each of the first, second, third and fourth walls has a height ranging from about 20 centimeters (cm) to about 50 cm. In an example, the cryobox 100 may have a length, breadth, and height ranging from about 20cm to about40 cm on the inside.

[0015] The first wall 104 includes multiple slots 1 12-1 , 1 12-2, ..., 1 12-N, also referred to as slots 1 12, that are perpendicular to the base surface 102. The slots 1 12-1 , 1 12-2, ..., 1 12-N extend along the height of the cryopreservation box 100 and perpendicular to the base surface 102 along an inner surface of the first wall 104. The slots 1 12 are formed as channels on the first wall 104 and may have a uniform cross-section. The slots 1 12 are configured to hold the female gametes carrier devices in an upright position within the cryopreservation box 100. In an example, a single female gametes carrier device may be held within one slot from the slots 1 12. The slots 1 12 are of a sectional-cylindrical shape. In an example, the slots 1 12 are of a sectional-cuboidal shape. Further, each of the slots 1 12 may have a hole (H) formed at the base surface 102 into which the female gametes carrier device are rested. The slot 1 12 has a depth in a range from 2 cm to 4 cm and cross-sectional diameter in a range from 2 mm to 10 mm. In an example, each of the slots may have a height ranging from about 10 cm to about 20 cm and a cross-sectional diameter ranging from about 0.02 cm to about 0.7 cm. An inlet chamber 122 is formed at one end of the first wall 104 and has a base sloping downwards towards the base surface 102 of the cryopreservation box 100.

[0016] Each female gametes carrier device has a first end and a second end, where the first end of the female gametes carrier device may fit into the hole (H) of a slot, from amongst the slots 1 12. The second end of the female gametes carrier device may protrude upwards for being gripped during retrieval of the female gametes carrier device from the cryobox 100. Each female gametes carrier device also has a marked face that is used for identification purposes. The user/embryologist would identify the correct female gametes carrier device to be retrieved based on the marked face. In an example, the marked face may be a name of the patient, a number indicating the number of female gametes held by the female gametes carrier device, the age of the patient, the name of the hospital that the patient visited, and the like. With the female gametes carrier device being held within the slots 1 12, the marked face may be oriented towards the user and thereby enabling the user to conveniently identify the female gametes carrier device to be gripped and retrieved from the cryobox 100.

[0017] The cryobox 100 has a downward sloping surface 1 14. The downward sloping surface 1 14 interfaces the base of the inlet chamber 122 and the base surface 102 of the cryopreservation box 100 to flow liquid nitrogen from the inlet chamber 122 to a first liquid nitrogen holding chamber 132 formed by the base surface 102, the first wall 104, the downward sloping surface 1 14, and the second wall 106 of the cryopreservation box 100. The second wall 106 is adjacent to the first wall 104. The inlet chamber 122 has a base sloping downwards towards the base surface 102 of the cryopreservation box allowing easy transfer of the liquid nitrogen from the cryobox 100 to the tank after the its use. A reservoir 124 is formed at another end of the first wall 104 and has a surface 126 sloping downwards from a specific height from the base surface 102 of the cryopreservation box 100 towards the base of the reservoir 124 to flow an excess liquid nitrogen to the liquid nitrogen holding chamber from the reservoir 124.

The base surface 102 includes second liquid nitrogen holding chambers 1 16, 1 18. One of the second liquid nitrogen holding chamber 1 16 is formed adjacent to the slope portion 1 14 at a corner formed at the junction of the inner surfaces of the first wall and the fourth wall 1 10. The inner walls at the corner where the second and third walls 106 and 108 meet are rounded such that the surface profile of the second liquid nitrogen holding chambers 1 16, 1 18 matches the outer surface profile of a cannister. Thus, the second liquid nitrogen holding chambers 1 16, 1 18 are configured to hold canisters vertically inside the liquid nitrogen level, into which the female gametes carrier device may be transferred. In an example, the first of the second liquid nitrogen holding chambers may have a depth ranging from about 20cm to about 40cm and a cross-sectional diameter ranging from about 5cm to about 20cm. The downward sloping surface 1 14 forms an obtuse angle with the base surface 102. The obtuse angle is in a range from 1 10 degrees to 60 degrees.

[0018] The canisters may hold multiple female gametes carrier devices. The canisters may be of a cylindrical shape and have a diameter equivalent to a diameter of a water bottle. A mouth, which is in an upper portion of the canister, is brought near to the first end of the female gametes carrier device, when the female gametes carrier devices are removed from the slots 1 12 and transferred into the canister. This ensures that the gametes/embryos present inside the female gametes carrier devices are safely and are transferred with ease into the canisters. The canisters holding the female gametes carrier devices may be then moved to the tanks for further long-term storage. [0019] The first of the second liquid nitrogen holding chambers holds larger sized canisters compared to the second of the second liquid nitrogen holding chambers. In an example, the second of the of the second liquid nitrogen holding chambers 1 18 may have a depth ranging from about 10cm to about 20cm and a cross-sectional diameter ranging from about 2 cm to about 7cm.

[0020] Further, the cryopreservation box 100 may include a separator wall 120. The separator wall 120 may connect the second wall 106 with the downward sloping surface 1 14. In an example, the separator wall 120 may extend from a center position of the second wall 106 till a point where it meets with an edge of the downward sloping surface 1 14. The separator wall 120 also forms an interface between the downward sloping surface 1 14 and of the bulb shaped wall of the second liquid nitrogen holding chambers. The separator wall 120 may be of a cuboid shape. The separator wall 120 may keep accidentally fallen female gametes carrier device at the base surfacel 02 as a barrier wall not allowing them to enter into the second liquid nitrogen holding chambers. The separator wall 120 has a height less than the specific height of the surface 126 of the reservoir 124.

[0021] The inlet chamber is of a cylindrical shape. The inlet chamber 122 is positioned at a corner of the cryopreservation box 100 where the first wall 104 and the fourth wall 1 10 meet. In an example, liquid nitrogen may be poured into the cryopreservation box 100 through the inlet chamber 122. The liquid nitrogen poured in the inlet chamber 122 may flow into the cryopreservation box 100 along the downward sloping surface 1 14. The liquid nitrogen flowed along the downward sloping surface 1 14 may be contained on the base surface 102. A substantial portion of the female gametes collection device pushed inside the slots 1 12 may thus remain submerged within the liquid nitrogen. In an example, the inlet chamber 122 may have a depth ranging from about 5 cm to about 40 cm and a cross-sectional diameter ranging from about 3 cm to about 7cm.

[0022] Further, the cryopreservation box 100 includes a reservoir 124. The reservoir 124 is also of a cylindrical shape and is of a same size as the size of the inlet chamber 122. The reservoir 124 is positioned at a corner of the cryopreservation box 100 where the first wall 104 and the second wall 106 meet. The reservoir 124 has a surface 126 coupled to a bottom of the reservoir 124. The surface 126 is a slope formed at a height from the base surface 102 sloping towards the bottom of the reservoir 124. The curvature portion 126 enables flow of liquid nitrogen into the reservoir 126, when a level of liquid nitrogen inside the cryopreservation box 100 exceeds a threshold level. This ensures that the level of liquid nitrogen stored inside the cryopreservation box 100 is maintained. Further, by monitoring the level of liquid nitrogen in the reservoir 124, the level of liquid nitrogen inside the cryobox 100 may be monitored. In an example, the second reservoir 124 may have a depth ranging from about 5 cm to about 40 cm and a cross-sectional diameter ranging from about 3 cm to about 7 cm.

[0023] The cryopreservation box 100 further includes a first holder 128 that may hold the female gametes collection device before usage and before the female gametes collection device are manipulated at the workbench. The first holder 128 may be of a cylindrical shape. The first holder 128 is positioned at a corner of the cryopreservation box 100 where the second wall 106 and the third wall 108 meet. The female gametes carrier device may also be held before usage and manipulation using a second holder 130. The second holder 1 30 is also of a cylindrical shape and is of a same size as the size of the first holder 128. The second holder 130 is positioned at a corner of the cryopreservation box 100 where the third wall 108 and the fourth wall 1 10 meet.

[0024] Fig. 2 illustrates a cross-sectional view of the cryopreservation box 100, according to an example. The first wall 104 of the cryopreservation box 100 includes slots 1 12 that are perpendicular to the base surface 102, where the slots 1 12 extend along the height of the cryopreservation box 100 as described in Fig. 1 . The depths of the first depression 1 16 and the second depression 1 18 are shown as D1 and D2, respectively, where D1 is greater than D2. Although, in the Figs. 1 and 2, two the liquid nitrogen holding chambers 1 16, 1 18r are shown for holding cannisters, in an example, more than two or less that two depressions may be present on the base surface 102. Further, the obtuse angle“O” of the slope portion 1 14 may be seen in Fig. 2.

[0025] Fig. 3 illustrates a cross-sectional view of the cryopreservation box depicting canisters, according to an example. The first wall 104 of the cryopreservation box 100 includes slots 1 12 that are perpendicular to the base surface 102, where the slots 1 12 extend along the height of the cryopreservation box 100. One female gametes collection device is held within one slot 1 12. Thus, the gametes/embryos present inside the female gametes collection devices are less exposed to air, as the female gametes carrier device may be quickly and conveniently transferred into the canisters. The canisters holding the female gametes collection device may then be taken to the liquid nitrogen tanks for future storage and/or transportation.

[0026] Although implementations of present subject matter have been described in language specific to structural features and/or methods, it is to be noted that the present subject matter is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained in the context of a few implementations for the present subject matter.