WO2020183482A1

WO2020183482A1 - Ovum culture tray

Info

Publication number: WO2020183482A1
Application number: PCT/IN2019/050487
Authority: WO
Inventors: Sravan Kumar PAYELI; Pavani Srividya MOCHARLA
Original assignee: Payeli Sravan Kumar
Priority date: 2019-03-14
Filing date: 2019-06-28
Publication date: 2020-09-17

Abstract

Examples of an ovum culture tray are described. In an example, an ovum culture tray (100) comprises a base surface (102), a tray wall (104) forming a boundary of the base surface (102), and a well (106) on the base surface (102). The well (106) has a circular base (108) and four walls (110) surrounding the circular base (108). The well has a square or rectangular open end opposite to the circular base (108). A wall, from amongst the four walls, is inclined at an obtuse angle with respect to a plane of the circular base (108). The well walls are in contact with surrounding material or substance that transfer heat into the well (106).

Description

OVUM CULTURE TRAY

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. The in vitro fertilization of ovum by the sperm cells results in development of embryos. The embryos are assessed and transferred to the uterus of the prospective mother for further development.

BRIEF DESCRIPTION OF DRAWINGS

[0002] The following detailed description references the drawings, wherein:

[0003] Fig. 1 illustrates an ovum culture tray for cell culture of ovum cells, according to an example;

[0004] Fig. 2 illustrates a sectional view of the ovum culture tray, according to an example;

[0005] Fig. 3 illustrates a perspective view of the ovum culture tray, according to an example;

[0006] Fig. 4 illustrates a perspective view of a porous lid for the ovum culture tray of Figs. 1 and 3, according to an example;

[0007] Fig. 5 illustrates another ovum culture tray for cell culture of ovum cells, according to an example;

[0008] Fig. 6 illustrates a sectional view of the ovum culture tray, according to an example;

[0009] Fig. 7 illustrates a perspective view of a porous lid for the ovum culture tray of Fig. 5, according to an example; and

[0010] Fig. 8 illustrates an ovum culture apparatus, according to an example. DETAILED DESCRIPTION

[0011] 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. An ovum is generally disposed in the follicular fluid. These follicles are randomly distributed inside or on the surface of the ovary. For IVF, the follicular fluid containing the ovum is to be collected from the follicles.

[0012] After the follicular fluid is collected from the body of the prospective mother, the follicular fluid is temporarily stored in an ovum culture tray where sorting, screening and cell culture of ova collected from the follicular fluid is performed. Also, ovum is collected from the follicular fluid and suspended in a culture medium in the ovum culture tray for an intermediate or transient time period for insemination. The culture medium may include an oil and other chemical substances. After the insemination procedure is conducted, the ovum is transferred to an incubator where the ovum is cultured for 0 to 6 days before embryo transfer or flash freezing the ovum/embryos for storage and future use.

[0013] The follicular fluid collected from the human body has a temperature of about 37 degrees Celsius (C) which resembles the optimal temperature inside the human body. After collection of the follicular fluid, during the cell culture, the surroundings of the collected follicular fluid is at an ambient temperature of about 20 to 25 degree C (room temperature). This change in temperature from 37 degrees C inside the human body to the room temperature is not physiological and may cause unwanted damages to the ovum and thereby reduce the fertilization rate or suboptimal development of the embryos.

[0014] Thus, during the cell culture, in order to maintain the temperature of the collected ovum/embryo at about 37 degrees C, the ovum culture tray in which the collected/inseminated ova are stored is mounted on a hot metal plate which provides heat to the ovum culture tray and in turn to the ovum stored in the tray from bottom surface. Typically, the ovum culture tray, also referred to as the tray, has well-shaped enclosures in which the ova are stored. The wells are cylindrical in shape and are formed on the tray. [0015] Due to the cylindrical shape of the wells, when the ovum culture tray is placed under a light microscope for viewing the ova cells, the cylindrical walls of the well may cast a shadow at the periphery of the base of the wells. The cylindrical walls of the well may cause a hindrance in the path of light from the light microscope and thereby the shadow may be case at the peripheral regions. Due to the shadow cast at the periphery, the ova cells suspended in the culture medium which remain scattered at the periphery of the base of the wells are difficult to view or locate under the light microscope while manipulating ovum during the cell culture. This may be referred to as shadow effect. Thus, extraction of the ova cells from the culture medium which are scattered near the periphery becomes difficult and time consuming. Thus, the ova cells lying near the periphery towards the handling side may lead to suboptimal handling/manipulation.

[0016] Further, when the ovum culture tray is placed under the light microscope, holding pipettes for handling/manipulating the ovum are required to be inclined at a specific angle with respect the horizontal because of space constrain resulting from lenses of the microscope being at a close proximity to the ovum culture tray. Since holding pipettes are inclined at the specific angle, therefore a certain portion of the bottom of cylindrical well remains inaccessible and thus the ova/embryos suspended in the inaccessible portions may not be handled/manipulated .

[0017] The present disclosure describes an ovum culture tray and an ovum culture apparatus, where the structure of the well(s) in the tray are such that the shadow effect is reduced or eliminated. The ovum culture tray of the present disclosure has a base surface, a tray wall forming a boundary of the base surface, and a well on the base surface. The well has a circular base and four walls surrounding the circular base, where each wall is inclined at an obtuse angle with respect to a plane of the circular base.

[0018] The walls of the well inclined at obtuse angles with respect to the plane of the circular base of the well, enable peripheries of the circular base to be accessible by the holding pipettes of the user/embryologist for manipulating the ova without hindrance. With the four walls surrounding the circular base, being inclined at the obtuse angle, the holding pipettes used to manipulate the ova may be inclined along the slope of the walls thereby accessing a greater area of the circular base of the well, consequently providing an enhanced freedom of movement while handling the ova in the ovum culture tray under the microscope.

[0019] Due to the incline of the wall of the well with respect to the plane of the circular base, the shadow effect may be reduced or eliminated thereby enabling the ova scattered near the periphery of the circular base, to be conveniently viewed and manipulated. Further, in an example, according to the present disclosure, the tray wall may form an enclosed space on the base surface. The enclosed space may be used to store a liquid with high heat retention capacity, such as water. When the ovum culture tray of the present disclosure is placed on the hot plate with 37 degrees C, heat is transferred into the cultured medium through the base of the well, the water stored in the enclosed space may absorb, retain and transfer the heat horizontally through the walls of the well. This heat may be passed on to the culture medium and to the ova suspended in the culture medium stored in the wells thereby facilitating in maintaining the temperature of the ova at the optimal range of about 37 degrees C with minimized fluctuations when the ovum culture tray is either on the hot surface or during the transition between hot surface and incubator or micromanipulator where the ovum culture tray is exposed to room temperatures. Thus, with the ovum culture tray and the ovum culture apparatus of the present disclosure, the culture medium and the ovum suspended in the culture medium may be maintained at temperatures close to 37 degrees C for a longer period of time thereby reducing fluctuations in the temperature.

[0020] 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. 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. [0021] Fig. 1 illustrates an ovum culture tray 100 for cell culture of ovum cells collected through follicular aspiration, according to an example. The ovum culture tray 100 is also referred to as the tray 100. Although in Fig. 1, the tray 100 is shown to have a rectangular shape, in an example, the tray may have a different geometrical shape. The tray 100 has a base surface 102, as shown in Fig. 1. In an example, the tray 100 may include a heating surface (not shown) opposite to the base surface 102. The heating surface absorbs heat from a heating pate on which the tray 100 may be kept while working with the culture medium. In an example, the heating plate may be a metallic plate maintained at elevated temperatures and may be attached to the heating surface.

[0022] The tray 100 further comprises a tray wall 104 which forms a boundary of the base surface 102. The tray wall 104 may have a height Ή’, as shown in Fig. 2. In an example, the height Ή’ of the tray wall 104 ranges from about 1 centimeter (cm) to about 1.5cm and a thickness of the tray wall 104 ranges from about 0.05 cm to about 2 cm. In an example, the tray 100 is formed from one of glass or polystyrene that allows transparent microscopic vision.

[0023] The tray 100 further includes a well 106 formed on the base surface 102. The well 106 has a circular base 108. The circular base 108 forms the bottom of the well 106 and lies in the same horizontal plane as that of the base surface 102, as can be seen from Fig. 2. In an example, the circular base 108 may have a diameter ranging from about 0.5 cm to about 2 cm. Although the ovum culture tray 100 is shown to have a single well, in an example, the ovum culture tray may include plurality of wells.

[0024] The well 106 has four walls, viz., 110-1, 110-1, 110-3, and 110-4 surrounding the circular base 108, as shown in Fig. 1. The four walls 110-1 to 110- 4 may also be referred to as walls 110. The wall 110-4, from amongst the walls 110, is inclined at an obtuse angle Ό’ with respect to a plane of the circular base 108, as shown in Fig. 2, and is also referred to as a sloping wall 110-4. In an example, the obtuse angle Ό’ ranges from about 120 degrees to about 155 degrees (on the inside of the well 106). The sloping wall 110-4 has a varying thickness which is maximum at the base surface 102 and reduces as the height of the sloping wall 110-4 increases. In an example, the maximum thickness‘t’ of the sloping wall 110-4 at the base surface 102 is greater than a thickness of other walls 110-1, 110-2, and 110-3. In an example, the maximum thickness‘t’ ranges from about 0.5 cm to about 1 cm. The well 106 has an open end opposite to the circular base 108. The open end has a rectangular shape and is surrounded by the four walls 110. In an example, the height Ή’ of the tray wall 104 is greater than a height of each of the walls 110 of the well 106.

[0025] The well 106 includes separator walls 116 formed on the circular base 108. The separator walls 116 divide the circular base 108 into a plurality of compartments or sectors. The separators walls 116 are in the form of ridges and extend perpendicular to the circular base 108. In an example, the separator walls 116 may be formed from glass or polystyrene or any medical grade disposable material. In an example, the separator walls 116 may have a height ranging from about 0.1 mm to about 0.5 mm.

[0026] Fig. 3 illustrates a perspective view of the tray 100. The tray 100 includes a first plurality of projections, of the base surface 102, abutting the tray wall 104. A projection 112-1 abutting the tray wall 104 is shown in Fig. 3. Similar projections 112-2 and 112-3, and 112-4, are also shown abutting the tray wall 104. The projections 112-1 to 112-4 are also referred to as the first plurality of projections 112 or projections 112. The projections 112 are extended portions which emanate perpendicular to the base surface 102 and interface with the tray wall 104.

[0027] Each of the projections 112 extend perpendicular to the base surface 102 and acts a seat for positioning a porous lid (shown in Fig. 4) which overlays on the base surface 102. Each of the projections 112 has a top face on which edges of the porous lid rests. In an example, a height‘hi’ of each of the first plurality of projections 112 is less that the height Ή’ of each of the walls 110 of the well 106. In an example, the height of each of the first plurality of projections 112 from the base surface 102 ranges from about 0.5 cm to about 1 cm.

[0028] The tray 100 further includes a projection formed at each corner of the tray 100. As shown in Fig, 3, projections 114-1, 114-2, 114-3, and 114-4 are formed at the four comers of the tray 100 and are referred to as a second plurality of projections 114 or projections 114. Each of the projections 114 extend from the tray wall 104 and perpendicular to the base surface 102 in a direction away from the base surfacel02. The projections 114 are stubs extending from the comers of the tray wall 104. Each of the projections 114 has a height greater than the height Ή’ of the tray wall 104.

[0029] In an example, a tray cover (not shown) can rest on the projections 114 and overlay on the porous lid. The tray cover may be positioned on the second plurality of projections 114, such that there is a gap between the tray cover and a top edge of the tray wall 104. In an example, the tray cover is a solid non-porous lid that covers the porous lid. In an example, the tray cover is formed from one of glass or any medical grade plastic material such as polystyrene.

[0030] Further, in an example, the tray 100 includes gripping portions 118. The gripping portions 118 may be formed integral to the tray wall 104. The gripping portions 118 protrude parallel to the base surface 102 in a direction away from the well 106. The gripping portions 118 may allow a user to hold the tray 100 for moving of the tray. In an example, the gripping portions 118, on either side of the tray 100, may have different surface profiles. For example, the gripping portions 118 on one side may have pointed edges and the gripping portion on other side may have bevelled edges. This difference in surface profile of the gripping portions 118 enable the user/embryologist to comprehend an orientation of the tray 100 even without looking at the tray. Thus, when the tray 100 is kept inside an incubator or micromanipulator and the user/embryologist holds the tray 100 to bring the tray 100 out of the incubator, the user may identify one or more trays based on the position of the gripping portions 118 of those trays. For example, a tray may be kept inside an incubator such that the gripping portions with bevelled edges of the tray faces the door of the incubator. The user on touching the gripping portion with bevelled edges of that tray may realize that this is the current tray on which he/she was working. Thus, without pulling the tray out of the incubator, the user may be able to identify the tray by feeling the gripping portions 118. Consequently, not all trays need to be moved out of the incubator and a specific tray may be selectively moved for use thereby facilitating of ease in ova handling.

[0031] Fig. 4 illustrates a perspective view of a porous lid 200. The porous lid 200 may be positioned on projections, such as the first plurality of projections 112 of a base surface, such as the base surface 102, of an ovum culture tray, such as the tray 100. The porous lid 200 is configured to overlay on the base surface 102. The porous lid 200 includes a slot 202. The slot 202 is positioned on the porous lid 200 such that a well, such as the well 106, is fittable within the slot 202, when the porous lid 200 is positioned to rest on the projections 112 and overlay on the base surface 102. The length and breadth of the slot 202 may be identical to those of the well, such as the well 106, which is to fit in the slot 202. In an example, the porous lid may include a plurality of slots corresponding to a plurality of wells in the ovum culture tray. Such a porous lid with a plurality of slots is illustrated in Fig. 7. The porous lid 200 has a mesh-like structure 204 forming the pores 206. In an example, a pore has a height, a length and a breadth ranging from about 0.1 cm to about 0.3 cm. In an example, the porous lid 200 is formed from one of glass and polystyrene or any medical disposable material.

[0032] Fig. 5 illustrates an ovum culture tray 300, according to an example. The ovum culture tray 300 includes three wells, viz., 302-1, 302-2, and 302-3. The wells, 302-1, 302-2, and 302-3 may be referred to as wells 302. Although the ovum culture tray 300 is shown to have three wells, in an example, the ovum culture tray 300 may include less than three or more than three wells.

[0033] Each of the wells 302 includes similar features as that of the well 106, shown in Figs. 1 to 3. Each of the wells 302 have a circular base bounded by four walls. The circular base is similar to the circular base 108, as shown in Fig. 1. Each of the wells 302 has a sloping wall, such as the sloping wall 110-4 of the well 106 shown in Figs. 1 to 3. With reference to Fig. 5 and Fig. 6, the well 302-1 has a sloping wall 304-1, the well 302-2 has a sloping wall 304-2, and the well 302-3 has a sloping wall 304-3. The sloping walls 304-1 to 304-3 of each of the wells 302 is inclined at an obtuse angle with respect to a plane of the circular base. In an example, the obtuse angle ranges from about 120 degrees to about 165 degrees (on the inside of the well). Each of the wells 302 also include separator walls, such as the separator walls 116 as shown in Fig. 1, formed on their respective circular base.

[0034] The ovum culture tray 300 includes a base surface 304, similar to the base surface 102, as shown in Fig. 1. The ovum culture tray 300 further includes a tray wall 306 forming a boundary of the base surface 304. The tray wall 306 is similar to the tray wall 104, as shown in Figs. 1 to 3. The wells 302 of the ovum culture tray 300 are separated by a plurality of interspaces 308 in the base surface 304. The interspaces 308 refer to portions of the base surface 304 where wells 302 are not present.

[0035] Further, although not shown in Fig. 5, the tray 300 also includes the first plurality of projections, such as the first plurality of projections 112 as shown in Fig. 3, for positioning of a porous lid. The tray also includes the second plurality of projections, such as the second plurality of projections 114 as shown in Fig. 3, for positioning of a tray cover.

[0036] Fig. 7 illustrates a perspective view of a porous lid 400, according to an example. The porous lid 400 may be positioned on the first plurality of projections of the ovum culture tray 300. The porous lid 400 is configured to overlay on the base surface 304 of the tray 300. The porous lid 400 includes a plurality of slots 402-1, 402-2, and 402-3 corresponding to the wells 302-1, 302-2, and 302-3 of the tray 300. The slots 402-1 to 402-3 are positioned on the porous lid 400 such that each of the wells 302-1 to 302-3 are fittable in a respective slot from amongst the slots 402-1 to 402-3, when the porous lid 400 is positioned to rest on the first plurality of projections of the tray 300. Thus, on placing the porous lid on the first plurality of projections of the tray 300, the well 302-1 fits in the slot 402- 1, the well 302-2 fits in the slot 402-2, and the well 302-3 fits in the slot 402-3. The porous lid 400 has a mesh-like structure 404 forming the pores 406. The mesh-like structure 404 is similar to the mesh-like structure 204 and the pores 406 are similar to the pores 206, as shown in Fig. 4.

[0037] Fig. 8 illustrates an ovum culture apparatus 500, according to an example. The ovum culture apparatus may include an ovum culture tray, similar to the ovum culture tray 100 or 300. Although in Fig. 8, the tray 100 is illustrated, in an example the tray 300 may also be used in the ovum culture apparatus 500, also referred to as the apparatus 500. A porous lid, such as the porous lid 200 may overlay on the base surface of the ovum culture tray 100.

[0038] Fig. 8 also shows a tray cover 502 to overlay on the porous lid. The tray cover may be positioned on the second plurality of projections 114. in an example, a heating plate may be attached to the heating surface opposite to the base surface 102. The ovum culture tray 100, the porous lid 200 and the tray cover 502 may be assembled together to form a single unit viz., the ovum culture apparatus 500. Similarly, the tray 300, the porous lid 400, and the tray cover 502 may be assembled together to form an ovum culture apparatus.

[0039] Consider that the tray 100, as described through Figs. 1 to 3, and the porous lid 200, as described through Fig. 4, is to be used for cell culture of ova cells. During operation, the tray 100 may be filled with sterile water. The sterile water is filled in portions of the base surface 102 where the well 106 is not present. No water is filled inside the well 106. Thus, the wells are surrounded by the sterile water held in the base surface 102 bounded by the tray wall 104. The well 106 is filled with the culture medium on which the ova cells are suspended. The porous lid 200 is overlaid on the base surface 102. Over the porous lid, the tray cover 502 is placed. The tray is placed on a metallic heating plate. Thus, the tray 100, the porous lid 200, tray cover 502, and the metallic heating plate are assembled to form the ovum culture apparatus, such as the apparatus 500.

[0040] The heating plate heats up the culture medium and the sterile water surrounding the wells upto a predefined temperature, such as 37 degrees Celsius. The heat may be absorbed directly by the culture medium stored in the well 106 through the circular base 108 of the well 106. Further, since the tray 100 is filled with the sterile water, the water absorbs the heat which may be transferred to the culture medium stored in the well 106 through the walls 110 of the well 106. Thus, heat may be transferred to the culture medium in the wells directly from the heating plate and from the water surrounding the wells from two dimensions, which may help in maintaining a temperature of the culture medium at the optimal range of about 37 degrees Celsius over surface heating alone. [0041] Further, the porous lid 200 is fitted onto the tray 100, such that the well 106 fits into the slot 202. The pores 206 of the porous lid 200 allow in circulation of air over the surface of the water stored surrounding the well 106 thereby maintaining an optimal relative humidity in the vicinity of the well 106 as in a closed physical system. This enables the relative humidity of the culture medium to be maintained at a predefined level and thereby reduces chances of molality changes of the culture medium thereby increasing efficiency of the cell culture conditions in the culture medium. Further, since the relative humidity of the culture medium is maintained at a predefined level, changes in osmolality and pH are also reduced/eliminated thereby enabling efficient cell manipulation of the ova cells.

[0042] Further, the tray cover 502 is positioned over the porous lid 200 and rests on the second plurality of projections 114 on four comers of the tray 100 such that, there is a gap between the tray cover 502 and a top edge of the tray wall 104. The gap allows efficient gaseous exchange and aeration in the culture medium when the tray 100 is placed the incubator thereby improving buffer capacity of the culture medium and consequently preserving physiological pH of the culture medium. When the tray cover 502 is placed on the porous lid 200, the ovum culture apparatus 500 behaves as a closed physical system thereby reducing/eliminating transfer of energy or transfer of mass. Thus, relative humidity of the air and gaseous exchange at the vicinity of the wells containing the culture medium is maintained at a predefined level. Since the relative humidity is maintained at the predefined level, changes in osmolality and pH of the ova/embryo are also reduced/eliminated thereby enabling efficient cell manipulation of the ova cells/embryos.

[0043] Further, since the well 106 is made of the circular base 108 and the open end of the well 106 has a rectangular or square shape, the shadow effect may be reduced. Thus, the ova cells lying in the periphery of the circular base 108 of the well 106 may also be efficiently captured and utilized for ovum manipulation. Also, the incline of the sloping wall 110-4 facilitates convenient handling of the ova cells during sorting, screening, and manipulation. Although the following description is provided with reference to the tray 100 and porous lid 200, the above description with suitable modifications is also applicable mutatis mutandis to the tray 300 and the porous lid 400.

[0044] 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.

Claims

I/We claim:

1. An ovum culture tray (100, 300) comprising:

a base surface (102, 304);

a tray wall (104, 306) forming a boundary of the base surface (102, 304); and a well (106) on the base surface (102), the well (106) having:

a circular base (108); and

four walls (110) surrounding the circular base (108), wherein a wall, from amongst the four walls (110), is inclined at an obtuse angle with respect to a plane of the circular base (108).

2. The ovum culture tray (100, 300) as claimed in claim 1, wherein the well (106) has an open end opposite to the circular base (108), the open end has a rectangular shape and is surrounded by the four walls (110).

3. The ovum culture tray (100, 300) as claimed in claim 1, wherein the obtuse angle ranges from about 120 degrees to about 165 degrees.

4. The ovum culture tray (100, 300) as claimed in claim 1, wherein the base surface (102) has a first plurality of projections (112) abutting the tray wall (104, 306), each of the first plurality of projections (112) extending perpendicular to the base surface (102, 304) and acts a seat for positioning a porous lid (200, 400) to overlay on the base surface (102, 304).

5. The ovum culture tray (100, 300) as claimed in claim 4, further comprising: a second plurality of projections (114) for positioning a tray cover to overlay on the porous lid (200, 400), each of the second plurality of projections (114) extending from the tray wall (104, 306) perpendicular to the base surface (102, 304) in a direction away from the base surface (102, 304), wherein the tray cover is positioned on the second plurality of projections (114) such that there is a gap between the tray cover and a top edge of the tray wall (104, 306).

6. The ovum culture tray (100, 300) as claimed in claim 1, wherein the well (106) comprises a plurality of separator walls (116) which divide the circular base (108) into a plurality of compartments.

7. The ovum culture tray (100, 300) as claimed in claim 1, wherein the tray wall (104, 306) has a gripping portion (118) protruding parallel to the base surface (102, 304) and in a direction away from the well (106).

8. The ovum culture tray (100, 300) as claimed in claim 1, wherein the tray wall (104, 306) has a greater height than the wall of the well (106).

9. An ovum culture tray (100, 300) comprising:

a base surface (102, 304);

a tray wall (104, 306) forming a boundary of the base surface (102, 304); and a plurality of wells (302) on the base surface (102, 304), a well from the plurality of wells (302) having:

a circular base; and

four walls surrounding the circular base, wherein a wall, from amongst the four walls, is inclined at an obtuse angle with respect to a plane of the circular base.

10. The ovum culture tray (100, 300) as claimed in claim 9, wherein the well has an open end opposite to the circular base, the open end has a rectangular shape and is surrounded by the four walls.

11. The ovum culture tray (100, 300) as claimed in claim 9, wherein the obtuse angle ranges from about 120 degrees to about 165 degrees.

12. The ovum culture tray (100, 300) as claimed in claim 9, wherein the well comprises a plurality of separator walls which divide the circular base into a plurality of compartments.

13. The ovum culture tray (100, 300) as claimed in claim 9, wherein the ovum culture tray comprises a porous lid (200, 400) to overlay on the base surface (102, 304), the porous lid (200, 400) comprising:

a plurality of slots (202, 402-1-402-3) positioned on the porous lid (200, 400) such that each of the plurality of wells are fittable in a respective slot from amongst the plurality of slots (202, 402-1-402-3).

14. The ovum culture tray (100, 300) as claimed in claim 9, further comprising: a tray cover (502) positioned to overlay on the porous lid (200, 400), wherein the tray cover (502) is positioned on a second plurality of projections, each of the second plurality of projections extending from the tray wall perpendicular to the base surface in a direction away from the base surface, wherein the tray cover is positioned on the second plurality of projections such that there is a gap between the tray cover and a top edge of the tray wall.

15. The ovum culture tray (100, 300) as claimed in claim 9, wherein the plurality of wells (302) is separated by a plurality of interspaces (308) in the base surface (304).

16. An ovum culture apparatus (500) comprising:

an ovum culture tray (100, 300) comprising:

a base surface (102, 304);

a heating surface opposite to the base surface (102, 304);

a tray wall (104, 305) forming a boundary of the base surface (102, 304); and a well (106) on the base surface (102, 304), the well (106) having:

a circular base (108); and

four walls surrounding the circular base (108), wherein a wall, from amongst the four walls, is inclined at an obtuse angle with respect to a plane of the circular base (108); a porous lid (200, 400) to overlay on the base surface (102, 304), wherein the porous lid (200, 400) comprises a slot positioned on the porous lid such that the well is fittable in the slot;

a tray cover (502) to overlay on the porous lid (200, 400), wherein the tray cover (502) is positioned on a second plurality of projections, each of the second plurality of projections extending from the tray wall perpendicular to the base surface in a direction away from the base surface, wherein the tray cover is positioned on the second plurality of projections such that there is a gap between the tray cover and a top edge of the tray wall; and

a heating plate attached to the heating surface.

17. The ovum culture apparatus (500) as claimed in claim 16, wherein the well has an open end opposite to the circular base, the open end has a rectangular shape and is surrounded by the four walls.

18. The ovum culture apparatus (500) as claimed in claim 16, wherein the obtuse angle ranges from about 120 degrees to about 165 degrees.

19. The ovum culture apparatus (500) as claimed in claim 16, wherein the well comprises a plurality of separator walls which divide the circular base into a plurality of compartments.