TECHNICAL FIELD

[0001] The present subject matter relates, in general, to separation of biological material from biological fluids and, in particular but not exclusively, to separation of oocytes from follicular fluids under microscope.

BACKGROUND

[0002] Medical procedures related to Assisted Reproductive Technology

(ART) applications, such as in-vitro fertilization (IVF) involve follicular aspiration, cryo-preservation, etc. During follicular aspiration, follicular contents, i.e., follicular fluid containing oocytes may be aspirated from follicles, for example, by puncturing the follicles from a human ovary with an ovum pick up needle.

BRIEF DESCRIPTION OF DRAWINGS

[0003] The detailed description is provided with reference to the accompanying figures. It should be noted that the description and the figures are merely examples of the present subject matter and are not meant to represent the subject matter itself.

[0004] FIG. 1A depicts a perspective view of an oocyte filter, according to example implementations of the present subject matter;

[0005] FIG. 2 illustrates a perspective view of an oocyte filter, according to an example implementation of the present subject matter;

[0006] FIG. 3 illustrates perspective view of a filtration unit, according to example implementations of the present subject matter;

[0007] FIGS. 4A & 4B illustrate a top view and a bottom view respectively, of a filtration unit, according to an example implementation of the present subject matter; and [0008] FIGS. 5 A & 5B illustrate different perspective views of a filtration unit, according to an example implementation of the present subject matter.

[0009] Throughout the drawings, identical reference numbers designate similar elements, but may not designate identical elements. The figures are not drawn to the scale, and the size of some parts may be exaggerated for better illustration of the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

DETAILED DESCRIPTION

[0010] In-vitro fertilization (IVF) procedures facilitate in fertilizing an oocyte (egg) with a sperm in a test tube or plate. In the IVF procedures, oocytes are developed and matured in multiple follicles that are grown in a human ovary over a period of time during controlled ovarian stimulation or controlled ovarian hyper stimulation (COH). Each matured follicle usually consists of about 2 milliliters (ml) to about 3 ml of follicular fluid containing single oocyte or no oocyte. The oocytes have a size of around 100 microns. The oocytes are surrounded by tightly packed layers of cumulus cells forming an oocyte cumulus complex (OCC). The OCC so formed may have an overall size of about 200 microns to about 500 microns with intact cumulus cells depending on the degree of maturation of the oocyte.

[0011] In IVF procedures, initially follicular fluid containing the OCC is collected from the patient. For example, as part of an ovum (egg) pick up process, follicular content from multiple follicles is aspirated. The aspirated follicular content may mainly include follicular fluid, OCC, and follicular tissue. It may also contain blood or ovarian tissue collected from ovary during aspiration. Thereafter, the follicular content is screened visually in a transparent bottom dish, such as a petri dish, while looking under a microscope, such as a stereo zoom microscope in an IVF lab. The OCC may thereafter be hand-picked with appropriate sterile tools from the transparent bottom dish and is separated from the follicular fluid for being used for downstream processing, such as invitro-fertilization or intra cytoplasmic sperm injection or oocyte preservation.

[0012] As the follicular content is screened for OCC while observing under the microscope, a medical practitioner or an embryologist may have to screen complete surface area of the dish of follicular fluid along with the oocytes. For example, generally, total follicular content may range about 10 ml to about 100 ml and an oocyte volume may be about 0.2 ml to about 1ml on an average. Moreover, a focal area of the microscope may accommodate about 0.5 ml to about 2 ml of follicular fluid in one instance, as a result, a field of view (focal area) of the embryologist may become restricted. To cover an entire area of the petri dish of different sizes for being able to screen the entire volume of the follicular content, the medical practitioner or the embryologist may have to screen through the microscope about 20 to 50 times of microscopic focal visions. As a result, separation of oocytes may become tedious and time-consuming for the embryologist or the medical practitioner.

[0013] In addition, the follicular fluid often includes contaminated blood and ovarian tissue, which hinders the transparency and is sometimes prone to clotting. Due to these reasons, it may be tedious and probability of oocyte loss is inevitable due to human error for the medical practitioner or the embryologist to identify and separate the microscopic sized oocytes. Therefore, the process of screening and separation of the oocytes may become complex and time consuming. The microscopic nature of oocytes may also pose constraints for the medical practitioner while separating the oocytes from the follicular fluid. In addition, when more number of cases (patients) are to be handled in one go, chances of human error and strain would increase.

[0014] Furthermore, when the follicular content containing the oocytes is poured into the petri dish for identification and separation of the oocytes, the follicular fluid may spread across the petri dish. Screened follicular fluid is decanted into an additional disposable container, which is an additional step of handling biological fluid that exposes the medical practitioner to spill over. As more time is spent on the handling of biological fluids, safety of an end user is jeopardized.

[0015] The present subject matter describes oocyte filters and filtration units, which facilitate in isolating the oocytes from the follicular fluid in an efficient and time saving manner. The oocyte filter includes a transparent base, thereby facilitates a medical practitioner or an embryologist to directly place the oocyte filter under a microscope and observe while screening. In an implementation, the filtration unit may minimize contact of the medical practitioner or the embryologist with contaminated follicular content. In another implementation, the filtration unit may filter out total follicular content by concentrating the follicular contents in a single microscopic focal view, thereby allowing the embryologist to separate the oocytes quickly and efficiently. The information of total follicular tissue may be utilized to assess or understand the nature of the follicle cohort and associated oocyte quality.

[0016] Various example implementations of the present subject matter describe an oocyte filter and a filtration unit. In an example implementation, the oocyte filter may include a cylindrical body portion with an open top portion and a transparent base portion. The cylindrical body portion may include a mesh having a plurality of pores to filter out total follicular contents. For example, the follicular contents that are above a pre-defined size may be filtered out by the plurality of pores. In an example, the bottom portion of the oocyte filter may have a diameter corresponding to a diameter of a focal area of a microscope. This may allow the embryologist to directly place the oocyte filter under the microscope. As a result, the embryologist may easily locate, isolate or extract oocytes from a smaller area defined by the oocyte filter.

[0017] In another example implementation, the filtration unit of the present subject matter comprises a bottom dish and a lid to cover the bottom dish. In an example, the bottom dish includes a side wall at a bottom portion of the filter. Further, the filtration unit includes the oocyte filter fixedly attached to the bottom dish. For example, the oocyte filter is attached to the transparent bottom surface. Thus, when the follicular content is poured on the bottom dish, the lighter, unwanted follicular content may flow out and the side wall may keep residual fluid to avoid OCC dry out. Further, heavy follicular content, such as OCC may be retained within the oocyte filter with residual fluid content. The filtration unit of the present subject matter thus facilitates the embryologist to filter the oocytes in a single microscopic view without having to adjust the focus consecutively to cover the entire petri dish surface for the oocyte screening. Further, the filtration unit allows the embryologist to extract the oocytes while continuously looking through the microscope. As a result, the filtration unit enhances oocyte recovery during the IVF procedures.

[0018] Although the biological material has been described herein as oocytes, this example is not meant to be construed in a limiting sense. The present subject matter is also applicable for other biological material, such as tissues, cells, embryos, and so on. Further, the present subject matter is applicable to all applications that uses single cell hand picking or automation.

[0019] The present subject matter is further described with reference to the accompanying figures. Wherever possible, the same reference numerals are used in the figures and the following description to refer to the same or similar parts. It should be noted that the description and figures merely illustrate principles of the present subject matter. It is thus understood that various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all the statements herein reciting principles, aspects, designs and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.

[0020] FIG. 1 depicts a perspective view of an oocyte filter 100, according to an example implementation of the present subject matter. In an example, the oocyte filter 100 may be fixedly attached to a cell-culture dish, such as a petri dish (not shown) or a transparent bottom plate or may be separately attached to the cell- culture dish or transparent bottom plate. The oocyte filter 100 includes a holding section 102 and a body portion 104. The holding section 102 hold the oocytes therewithin. Further, the holding section 102 may include a base made of a transparent material. The base may allow the medical practitioner to extract oocytes directly from the oocyte filter 100 under microscope without spreading the follicular fluid into a petri dish.

[0021] Generally, when the follicular fluid collected from both ovaries is transferred into the cell culture dish, because of a fixed size of the cell culture dish, the cell culture dish may get completely filled with the follicular fluid. As a result, a thick layer of the follicular fluid may be formed in the cell culture dish. Such thick layer is observed under the microscope, visibility of the oocytes may get affected. This may cause hindrance in oocyte identification and thus may affect an outcome of the IVF procedure.

[0022] To retain the required amount of follicular fluid inside the cell culture dish and the oocyte filter 100, in an example implementation, the holding section 102 may include a side wall 106. The side wall 106 may facilitate in retaining small amount of the follicular fluid (residual volume) inside the holding section 102 along with the oocytes to avoid drying of the oocytes held within the oocyte filter 100. Accordingly, the oocyte filter 100 is designed in a manner to prevent drying up of the oocytes. In an example, the holding section 102 may be made of a thermoplastic polymer, such as polypropylene.

[0023] In an example, the body portion 104 extends away from the holding section 102 to define a cylindrical or a cone shape. Further, the body portion 102 is made of a mesh 108. The mesh 108 may form an enclosure to separate the oocytes from the remaining follicular content. In an example, the mesh 108 may be formed of a material, such as polyester (PET) or Polyamides (PA). Further, the mesh 108 may facilitate in filtering out unwanted red blood cell fraction, such as residual tissues smaller than OCC, from the oocyte filter 100 into the cell culture dish. The mesh 108 may be shaped and sized in a manner to prevent passage of oocytes and OCC from the oocyte filter 100 into the cell culture dish. In an example, the mesh 108 may have a fixed pore size in a range of about 100 microns to about 500 microns. Further, the oocyte filter 100 may have a height of about 2 centimeters (cm) and a diameter of about 3 cm. Further, the body portion 104 may include an open end to visually inspect the oocytes held within the holding section 102.

[0024] In operation, the oocyte filter 100 may be positioned on the cell culture dish in a manner that the open end of the body portion 104 is in proximity to a lens of a microscope. In an example, the open end of the body portion 104 may have a diameter corresponding to a diameter of a focal area of the lens of the microscope to allow easy adjustment of the oocyte filter 100 underneath the lens. In an example, the diameter of the open end may be bigger or smaller than the focal area of the microscope. When a pre-determined quantity of the follicular fluid is poured inside the oocyte filter 100, the embryologist may look for the oocytes through the microscope and simultaneously extract the oocytes with the help of a pipette (not shown). The transparency of the base of the holding section 102 may facilitate the embryologist to easily visualize and locate the oocytes for extraction 100.

[0025] FIG. 2 illustrates a perspective view of an oocyte filter 200, according to an example implementation of the present subject matter. The oocyte filter 200 may include a holding section 202 and a body portion 204. The holding section 202 and the body portion 204 may be similar to the holding section 102 and the body portion 104. The body portion 204 may also include a mesh 206 similar to the mesh 108. As depicted in FIG. 2, the oocyte filter 200 may include a support member 208 extending outwards from a periphery of the body portion 204. The support member 208 is grippable to hold the oocyte filter 200. For example, the support member 208 may facilitate the medical practitioner or the embryologist to hold the oocyte filter 200. For example, to support member 208 may facilitate in carrying the oocyte filter 200 from one place to another. The support member 208 ensures convenient handling of the oocyte filter 200. Although the support member 208 is depicted as extending outwards from the periphery of the body portion 204, the support member 208 may have different designs for the purposes of the present subject matter.

[0026] Further, the mesh 206 facilitates in discarding any unwanted fluid.

In an example, the diameter of each of the pores of the mesh 206 may be less than a diameter of each of the oocytes and is configured to allow flow of the follicular fluids through the mesh. In an example, the mesh 206 has a pore size of about 200 microns to about 600 microns. In another example, the mesh 206 has a differential pore size ranging from about 200 microns to about 600 microns in gradual increasing manner. For example, the mesh 206 may have pores having sizes gradually increasing from 300 microns to 500 microns. As a result, the oocyte filter 200 may be used for filtering different biological materials. It will be evident to a person skilled in the art that the term ‘about’ used with respect to the pore size of the mesh 206 indicates ± 20% variation in the pore size to incorporate tolerances during manufacturing or otherwise.

[0027] Referring to FIG. 3, a perspective view of a filtration unit 300 is illustrated, according to an example implementation of the present subject matter. The filtration unit 300 may include a lid 302 and a bottom dish 304. Further, the lid 302 may be a removable cover for securely storing the filtration unit 300. In an example, the lid 302 and the bottom dish 304 are made of a glass material. The filtration unit 300 may include an oocyte filter 306 fixedly attached to the bottom dish 304. In an example, the oocyte filter 306 may be similar to the oocyte filter 100 and 200. The oocyte filter 306 may have a cylindrical shape or a conical shape (as shown in FIG. 3). As explained with reference to FIGS. 1 to 2, the oocyte filter 306 may include a mesh 308 to selectively filter the follicular content to retain the oocytes within the holding section 310.

[0028] In an example, the oocyte filter 306 may be attached to the bottom dish 304 such that the bottom dish 304 and the oocyte filter 306 form a single component. It will be understood to a person skilled in the art that when the oocyte filter 306 and the bottom dish 304 are integrated, the oocyte filter 306 does not include a separate base and a surface of the bottom dish 304 may act as the base of the oocyte filter 306.

[0029] In an implementation, the bottom dish 304 may also define a working area, i.e., an area inside the oocyte filter 306 that may be reachable with a pipette. Generally during operation, as the bottom dish 304 is placed under a microscope and an objective lens of the microscope is positioned above the bottom dish 304 at a distance, a right-handed person may not be able to reach the follicular fluid that may be collected at a 3’o clock position or right side of the oocyte filter 306, in the bottom dish 304. As mentioned above, the bottom dish 304 includes the working area such that while filling the follicular fluid into the bottom dish 304, follicular fluid contents having more weight, such as oocytes may be concentrated in the working area inside the oocyte filter 306 due to gravity.

[0030] FIGS. 4A & 4B illustrates a bottom view and a top view of a filtration unit 400, according to example implementations of the present subject matter. As is depicted in FIG. 4A, the filtration unit 400 includes a bottom dish 402. The bottom dish 402 may be similar to the bottom dish 304. Further, the filtration unit 400 includes an oocyte filter having a holding section (not shown) with a base 404. The base 404 of the filter may be a closed surface to retain the oocytes 406. In an example, the base 404 may be made of a transparent material to allow the medical practitioner to be able to clearly locate the oocytes under the microscope.

[0031] As the bottom dish 402 is made of the transparent material and the base 404 of the oocyte filter is transparent, the bottom view depicts the oocytes 406 confined within the base 404 of the oocyte filter. As a result, it becomes convenient and time saving for the embryologist or the medical practitioner to extract the oocytes 406 efficiently without re-adjusting the focus of the microscope several times.

[0032] Referring to FIG. 4B, a top view of the bottom dish 402 of a filtration unit (not shown) is illustrated. The bottom dish 402 may be provided with coupling mechanism, such as press fitting grooves 408 for enabling a filter, such as the oocyte filter 100 for being attached to the bottom dish 402. In an example, the oocyte filter may be coupled with the bottom dish 402 by a fastening means or any other methods in order to preserve fluid retention or to avoid leakage of fluid through contact between the oocyte filter and the bottom dish 402.

[0033] FIGS. 5 A & 5B illustrate different perspective views of a filtration unit 500, according to an example implementation of the present subject matter. As depicted in FIGS. 5 A & 5B, the filtration unit 500 may include a receptacle 502 and an oocyte filter 504. The receptacle 502 includes a cavity 506 for receiving the oocyte filter 504. In an example, the oocyte filter 504 is removably placed within the receptacle 502. As is clearly depicted in the FIGS., a profile of the cavity 506 is complimentary to a shape of the oocyte filter 504 to be able to receive the oocyte filter 504. In addition, one end of the receptacle 502 is closed by a stopper 508, such as a rubber cap. In an example, the receptacle 500 is made of a disposable, medical grade polypropylene or polystyrene materials.

[0034] The oocyte filter 504 may be similar to the oocyte filter 100 and 200.

For example, the oocyte filter 504 includes a holding section 510 to hold oocytes therewithin. The holding section 510 includes a base made of a transparent material. The oocyte filter 504 may also include a body portion 512 extending away from the holding section 510. The body portion 512 is made of a mesh 514 and forms an enclosure to separate the oocytes from the follicular content. The body portion 512 includes an open end to visually inspect the oocytes held within the holding section 510.

[0035] When the medical practitioner or the embryologist has to extract the oocytes, the oocyte filter 504 may be placed within the cavity 506. Thereafter, the follicular fluid may be poured in the oocyte filter 504. The mesh 514 may filter unwanted follicular fluid from the receptacle 502. Thereafter, the embryologist may remove the oocyte filter 504, using a support member 516, from the receptacle 502 and may place the oocyte filter 504 directly under a lens of a microscope or may transfer the content of the oocyte filter 504 into a cell culture dish for being observed under the lens of the microscope. Once the oocyte filter 504 is removed from the receptacle 502, the receptacle 502 carrying the unwanted follicular fluid may be discarded. Hence, the filtration unit 500 minimizes contact of infectious biological fluids. [0036] The filtration units 300, 400, 500 and the filters 100, 200, 306, 504 disclosed herein allows removal of unwanted fluid portion from the follicular content, the present subject matter substantially reduces human error and efforts of inadvertently missing out or discarding oocytes and speeds up the isolation of the oocytes from blood contaminated follicular fluid, by minimizing oocyte retention time in non-physiological conditions (blood). In addition, when light from the microscope falls on the cumulus cells surrounding the oocytes, the cumulus cells become bright, thereby facilitating easy and quick location and extraction of the oocytes from a reduced possible focal area of the screening plate.

[0037] Although the present subject matter has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, such as variety of petri plate shapes, filter shapes, range of pore sizes, transparent material used for the making, filter and plate combining methods adapted to the follicular fluid collection tubes as well as alternate embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter.