Microfluidic methods and apparatuses for denudation of oocytes utilizing oscillatory flow

Abstract

The present disclosure is generally directed to microfluidic methods and apparatuses for separating cells utilizing various techniques, such as oscillatory flow. One example application is the denudation of oocytes. Oocytes may need to be denuded before they can be effectively used in various applications, such as in vivo fertilization (IVF) applications. Certain aspects of the disclosure are thus directed to systems and / or methods that allow for more efficient cell separation. For instance, in some cases, the use of oscillatory flow through a channel may advantageously increase the efficiency of the separation process, while minimizing harmful effects on the cells. The microfluidic device may comprise various components, such as posts which optionally have extruded portions (e.g., teeth), multiple pressure sources to control fluid flow, or the like.

Description

[0001]MICROFLUIDIC METHODS AND APPARATUSES FOR DENUDATION OF OOCYTES UTILIZING OSCILLATORY FLOW RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 518,322, filed August 8, 2023, entitled “Microfluidic Methods and Apparatuses for Denudation of Oocytes Utilizing Oscillatory Flow,” and of U.S. Provisional Patent Application Serial No.63 / 518,323, filed August 8, 2023, entitled “Devices and Methods for Isolation of Biological Entities in Suspension.” Each of the above is incorporated herein by reference in its entirety. GOVERNMENT SUPPORT This invention was made with government support under Grant. No. HD105529 awarded by the National Institutes of Health. The government has certain rights in the invention. FIELD Certain aspects of the present disclosure are generally directed to microfluidic methods and apparatuses for denudation of oocytes utilizing oscillatory flow. BACKGROUND Oocytes contained within biological fluid oftentimes need to be denuded before they can be used in various applications, such as in vivo fertilization (IVF) applications. A typical biological fluid typically contain cumulus oocyte complex (COC), which are oocytes surrounded by layers of various secondary cells (e.g., non-oocyte cells such as cumulus cells, granulosa cells, etc.). For effective use in certain applications (e.g., in vivo fertilization procedures), oocytes need to be initially denuded. Several systems and / or methods for denuding oocytes are available. However, the systems and / or methods can be complicated and inefficient, and thus, more effective systems and / or methods of denuding oocytes are still needed. SUMMARY Certain aspects of the present disclosure are generally directed to microfluidic methods and apparatuses for denudation of oocytes utilizing oscillatory flow. The subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles. One aspect is generally drawn to a microfluidic device. In one set of embodiments, the device comprises a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, wherein at least some of the sub-channels have a minimum cross-sectional dimension of between about 80 micrometers and about 350 micrometers, and wherein the sub-channels define a denuder region having a length within the fluidic channel of no more than 100 millimeters; a first pressure source upstream of the plurality of posts; and a second pressure source downstream of the plurality of posts. In another set of embodiments, the device comprises a fluidic channel having an inlet and an outlet, wherein the fluidic channel has a minimum cross-sectional dimension of between about 80 micrometers and about 350 micrometers; a plurality of posts downstream of the fluidic channel, the posts spaced apart at a distance of no more than 120 micrometers; a first pressure source upstream of the plurality of posts; and a second pressure source downstream of the plurality of posts. Another aspect is generally drawn to a microfluidic device to process fluid and to isolate and denude oocytes for egg banking, egg freezing, and / or for in-vitro fertilization. In a first set of embodiments, the device comprises a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts; a first pressure source upstream of the plurality of posts; and a second pressure source downstream of the plurality of posts. Yet another aspect is generally drawn to a method. In one set of embodiments, the method is a method of preparing a fluid to isolate and denude an oocyte complex comprising an oocyte and bounded non-oocyte cells for egg banking, egg freezing, and / or in-vitro fertilization. In one embodiment, the method comprises passing the fluid through a fluidic channel comprising a plurality of posts such that the complex flows through sub-channels defined between neighboring pairs of posts. Another set of embodiments is generally drawn to a method of denuding an oocyte complex comprising an oocyte and bounded non-oocyte cells to separate the oocyte from the non-oocyte cells. In one embodiment, the method comprise passing the complex through a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, at least one of the sub-channels having a minimum cross-sectional dimension of between about 50 micrometers and 350 micrometers, the sub-channels defining a denuder region having a length within the fluidic channel of no more than 100 millimeters, such that at least 10% of the non-oocyte cells are removed when the complex flows through sub-channels. Still another set of embodiments is directed to a method of manipulating an oocyte complex comprising an oocyte and bounded non-oocyte cells. In certain embodiments, the method comprises causing a flow of fluid containing the complex in a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, such that the complex passes the plurality of posts at least 2 times. Yet another set of embodiments is directed to a method of denuding an oocyte complex comprising an oocyte and non-oocyte cells to separate the oocyte from the non-oocyte cells. In one embodiment, the method comprises causing a first flow of a fluid containing the complex in a first direction through a fluidic channel; removing at least some of the non-oocyte cells from the complex as the complex flows through the fluidic channel in the first direction; causing a second flow of the fluid containing the complex in a second direction through the fluidic channel; and removing at least some of the non-oocyte cells from the complex as the complex flows through the fluidic channel in the second direction. In another embodiment, the method comprises repeatedly causing flow of a fluid containing the complex through a fluidic channel, wherein at least 10% of the non-oocyte cells in the complex are removed during repeated flow of the complex through the fluidic channel. The method, in another set of embodiments, is a method of manipulating an oocyte complex comprising an oocyte and non-oocyte cells. In one embodiment, the method comprises causing a flow of fluid containing the complex in a fluidic channel such that the complex flows across an imaginary line within the fluidic channel at least 2 times, wherein the imaginary line is defined in a direction orthogonal to a direction of bulk fluid flow within the fluidic channel. In another embodiment, the method is a method of manipulating an oocyte complex comprising an oocyte and non-oocyte cells. The method, in certain cases, comprises causing a flow of fluid containing the complex in a channel dimensioned to allow the oocyte to flow through only if not bound to the non-oocyte cells; and repeating the causing step at least 2 times. In another set of embodiments, the method is a method of denuding an oocyte from bounded non-oocyte cells in a fluid. The method, in one embodiment, comprises inducing a first flow of the fluid containing one or more non-oocyte oocyte complex in a first direction through a microfluidic channel, such that at least a portion of the bounded non-oocyte cells is removed from the complex as the oocyte flows through the microfluidic channel in the first direction; and inducing a second flow of the fluid containing the one or more cumulous oocyte complex in a second direction opposite the first direction through the microfluidic channel, such that at least a portion of the bounded non-oocyte cells is removed as the oocyte flows through the microfluidic channel in the second direction. Still another set of embodiments is drawn to a method of preparing a fluid to isolate and denude a target entity-secondary entity complex comprising a target entity and one or more secondary entities to separate the target entity from the secondary entities. In certain cases, the method comprises passing the fluid through a fluidic channel comprising a plurality of posts such that the complex flows through sub-channels defined between neighboring pairs of posts. Yet another set of embodiments is directed to a method of denuding a target entity- secondary entity complex comprising a target entity and one or more secondary entities to separate the target entity from the secondary entities. In certain cases, the method comprises passing the complex through a fluidic channel comprising a plurality of posts defining sub- channels between neighboring pairs of posts, at least one of the sub-channels having a minimum cross-sectional dimension of between about 1 micrometer and about 1 mm, the sub- channels defining denuder region having a length within the fluidic channel of no more than 100 millimeters, such that at least 10% of the secondary entities are removed when the complex flows through sub-channels. Another set of embodiments is directed to a method of manipulating a target entity- secondary entity complex comprising an target entity and one or more secondary entities. In some cases, the method comprises causing a flow of fluid containing the complex in a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, such that the complex passes the plurality of posts at least 2 times. The method, in one set of embodiments, is a method of denuding an target entity- secondary entity complex comprising an target and one or more secondary entities to separate the target from the one or more secondary entities. The method, in certain embodiments, comprises causing a first flow of a fluid containing the complex in a first direction through a fluidic channel; removing at least some of the one or more secondary entities from the complex as the complex flows through the fluidic channel in the first direction; causing a second flow of the fluid containing the complex in a second direction through the fluidic channel; and removing at least some of the one or more secondary entities from the complex as the complex flows through the fluidic channel in the second direction. In another set of embodiments, the method is a method of denuding an target entity- secondary entity complex comprising an target entity and one or more secondary entities to separate the target entity from the one or more secondary entities. In certain cases, the method comprises repeatedly causing flow of a fluid containing the complex through a fluidic channel. In some embodiments, at least 10% of the one or more secondary entities in the complex are removed during repeated flow of the complex through the fluidic channel. In yet another set of embodiments, the method is a method of manipulating an target entity-secondary entity complex comprising an target entity and one or more secondary entities. In certain embodiments, the method comprises causing a flow of fluid containing the complex in a fluidic channel such that the complex flows across an imaginary line within the fluidic channel at least 2 times, wherein the imaginary line is defined in a direction orthogonal to a direction of bulk fluid flow within the fluidic channel. In still another set of embodiments, the method is a method of manipulating an target entity-secondary entity complex comprising an target entity and one or more secondary entities. In some cases, the method comprises causing a flow of fluid containing the complex in a channel dimensioned to allow the target entity to flow through only if not bound to the one or more secondary entities; and repeating the causing step at least 2 times. Another set of embodiments is drawn to a method of denuding an target entity from bounded one or more secondary entities in a fluid. In certain cases, the method comprises inducing a first flow of the fluid containing one or more target entity-secondary entity complex in a first direction through a microfluidic channel, such that at least a portion of the bounded one or more secondary entities is removed as the target entity flows through the microfluidic channel in the first direction; and inducing a second flow of the fluid containing the one or more target entity-secondary entity complex in a second direction opposite the first direction through the microfluidic channel, such that at least a portion of the bounded one or more secondary entities is removed as the target entity flows through the microfluidic channel in the second direction. Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the disclosure when considered in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures: FIG.1A is a schematic illustration showing fluid flow in a fluidic channel in a first direction, in accordance with some embodiments; FIG.1B is a schematic illustration showing fluid flow in a fluidic channel in a second direction, in accordance with some embodiments; FIGS.2A-2C are schematic illustrations showing a microfluidic device for denuding a target entity (e.g., an oocyte) and / or for generating oscillatory flow, in accordance with some embodiments; FIGS.2D-2E are schematic illustrations showing fluid flows through sub-channels between neighboring pairs of posts, in accordance with some embodiments; FIG.3A is a schematic illustration showing a fluidic channel formed by concentric walls, in accordance with some embodiments; FIG.3B is a schematic illustration showing a fluidic channel formed by concentric walls and comprising a plurality of posts therein, in accordance with some embodiments; FIG.4A is a schematic illustration showing a microfluidic device for denuding a target entity (e.g., an oocyte), in accordance with some embodiments; FIGS.4B-4C are microscopy images showing a plurality of oocyte complexes prior to oscillatory flow (FIG.4B) and after oscillatory flow (FIG.4C), in accordance with some embodiments; FIG.5 is a schematic illustration showing a fluidic constriction channel with uni- directional extruded features (e.g., teeth), in accordance with some embodiments; FIG.6 is a schematic illustration showing a fluidic constriction channel with bi- directional extruded features (e.g., teeth), in accordance with some embodiments; FIGS.7A-7D are schematic illustrations showing various example of extruded features, in accordance with some embodiments; FIG.8 is a schematic illustration showing an example of a constriction array with m = 6 or 7 per row, n = 6 rows, and N = 39, in accordance with some embodiments; FIGS.9A-9C are schematic illustrations showing various embodiments of a microfluidic device for generating oscillatory flow, in accordance with some embodiments; FIGS.10A-10C are microscopy images showing a device containing a plurality of saw- shaped teeth in the constriction area, in accordance with some embodiments; FIG.11 is a graph showing denudation time of oocytes at various oscillatory frequencies, in accordance with some embodiments; FIG.12 is a schematic illustration showing a closed-loop control system for controlling oscillatory flow and release of oocytes, based on their denudation level, in accordance with some embodiments; FIG.13 is a schematic illustration showing a specific design of a microfluidic device having a circular form factor, in accordance with some embodiments; FIGS.14A-14C are schematic illustrations showing microfluidic devices comprising angled walls, according to some embodiments; and FIG.15 shows a photomicrograph of denuded oocytes following passage through the denudation region shown in FIG.14C, in another embodiment. DETAILED DESCRIPTION The present disclosure is generally directed to microfluidic methods and apparatuses for separating cells utilizing various techniques, such as oscillatory flow. One example application is the denudation of oocytes. Oocytes may need to be denuded before they can be effectively used in various applications, such as in vivo fertilization (IVF) applications. Certain aspects of the disclosure are thus directed to systems and / or methods that allow for more efficient cell separation. For instance, in some cases, the use of oscillatory flow through a channel may advantageously increase the efficiency of the separation process, while minimizing harmful effects on the cells. The microfluidic device may comprise various components, such as posts which optionally have extruded portions (e.g., teeth), multiple pressure sources to control fluid flow, or the like. Certain aspects as discussed herein is generally directed to systems and methods for cell separation. One example application of cell separation is the denudation of oocytes. Oocytes contained within biological fluid oftentimes need to be denuded before they can be used in various applications, such as in vivo fertilization (IVF) procedures. Accordingly, certain aspects of the disclosure are directed to systems, devices and / or methods that collectively allow for a highly efficient oocyte denudation process. Certain devices and methods described herein may have various advantages compared to conventional devices and methods for oocyte denudation. Referring now to FIG.1, in one set of embodiments, an example microfluidic device comprises a fluidic channel having an inlet, and outlet, and a sub-channel (e.g., a constriction portion) between the inlet and outlet as shown in FIGS.1A-1B. As shown, the microfluidic device comprises a fluidic channel 110a having an inlet 150a, an outlet 170a, and a sub-channel 130a between the inlet 150a and the outlet 170a. During denudation of oocyte from bounded non-oocyte cells (e.g., various secondary cells bounded to the oocyte), one or more oocyte complexes may be repeatedly flowed across the fluidic channel. For example, the oocyte may be flowed back-and-forth, e.g., in an oscillatory fashion through the channel, and / or the oocyte may be flowed through the same channel in a certain direction a plurality of times. For example, in these figures, an oocyte may flow from the inlet 150a to the outlet 170a in a first direction 12 (e.g., from left to right) as shown in FIG.1A, and then from the outlet 170a to the inlet 150a in a second direction 14 (e.g., from right to left) as shown in FIG.1B. Such an oscillatory flow across the fluidic channel may be repeated multiple times within the fluidic channel. In other embodiments, however, the oocyte may be caused to flow in a single direction multiple times repeatedly through the microfluidic channel (e.g., in the direction shown in FIG.1A). In addition to the above, the device may be configured for repeated flow (e.g., oscillatory flow) of a fluid containing one or more oocyte complexes through a plurality of parallel microfluidic channels sized slightly larger than or about the size of an oocyte. The use of such repeated flows through a plurality of parallel channels of the device may allow for effective denudation of oocytes from a variety of fluids (e.g., follicular fluid, ovarian tissue, inseminated oocyte complexes), while preventing chip-clogging issues, and in some cases, it may reduce the duration of the denudation process and / or damage to the denuded oocytes. In some cases, the devices and / or methods described herein may result in effective cleaning of debris contained within biological fluids from the channels. Additionally, or alternatively, in some cases, the devices and / or methods described herein may allow for control of the degree of oocyte denudation by monitoring and / or controlling a variety of device parameters, e.g., such as the number of interactions between the oocytes and certain denudation features (e.g. teeth / jagged edges), direction of flow, flow rate, local velocity profile, and the like. Debris may include any organic (e.g., granulose cells, cell clumps, tissue, red blood cell clusters, blood clots, etc.) or inorganic material other than the targeted cells or cell complexes (e.g., cumulus-oocyte-complex, oocyte, etc.). Certain devices, according to some embodiments, may advantageously allow for visual temporal analysis of the denudation process within a localized section of the device and allow for closed-loop control of the denudation process based on one or more measured parameters. In addition, certain embodiments of the present disclosure may allow for denudation of oocytes within microfluidic channels having a relatively small size (e.g., length and footprint) compared to conventional microfluidic devices. Because the oocytes may be passed through the same channel repeatedly, longer channels and / or larger devices are not necessary for denudation of oocytes. Furthermore, in other embodiments, various other cells may be treated, e.g., in addition to or instead of oocytes. Non-limiting examples are discussed herein. In addition, the microfluidic device, according to some embodiments, may comprise one or more particularly advantageous features, e.g., such a plurality of posts and certain denudation features (e.g., extruded portions such as teeth) thereon, a plurality of microfluidic channels (i.e., sub-channel) between the posts, one or more pressure source and / or fluid controls, that allow for effective denudation of oocytes, as described in more detail below. In some embodiments, microfluidic systems and / or devices are generally described. In some cases, a microfluidic system may include at least one fluid conduit or channel (i.e., a microfluidic channel) having a cross-sectional dimension of less than about 1 millimeter (mm). However, it should be understood that the disclosure herein is not limited to only microfluidic systems. For example, in some cases, larger channels may be used. As described in more detail below, the microfluidic devices described herein may be employed for processing any of a variety of biological fluids to isolate and denude target entities from bounded secondary entities contained within the fluids. In one set of embodiments, the microfluidic devices described herein may be employed to process follicular fluid and to isolate and denude oocytes for egg banking, egg freezing, and / or for in-vitro fertilization. In one set of embodiments, the device comprises a fluidic channel comprising one or more posts (e.g., a plurality of posts) therein. The plurality of posts, according to some embodiments, define sub-channels between neighboring pairs of posts. Alternatively, or additionally, in some case, the plurality of posts may define sub-channels between post(s) and adjacent wall(s) of the fluidic channel. FIG.2A can be used to illustrate one such embodiment. As shown, a microfluidic device 100 comprises a fluidic channel 110 comprising a plurality of posts 120 therein. The plurality of posts 120 may define (parallel) sub-channels 130 between neighboring pairs of posts 120. As an example, neighboring posts 120a and 120b may together define sub-channel 130b therebetween. In some cases, sub-channel 130a may be defined by post 120a and wall 113 of fluidic channel 110. The use of parallel sub-channels may advantageously provide a plurality of paths for a target entity to pass through, which may reduce the risk of chip clogging and increase denudation efficiency. The plurality of posts within the fluidic channel may be arranged in any appropriate fashion. For instance, in one embodiment, the plurality of posts are arranged in an array across the fluidic channel. The array of posts, in some cases, may comprise one or more rows of posts, where each row comprises one or more posts. The posts may be arranged in any suitable arrangement, for example, a rectangular grid or in a staggered fashion, e.g., as shown in FIG. 2A. However, it should be understood that the plurality of posts is not limited to being arranged in an ordered fashion, and that in some cases, at least one of the plurality of posts may be arranged randomly across the fluidic channel. In some embodiments, the array of posts may comprise n number of rows of post(s) and / or sub-channels, where n is at least 1, at least 2, at least 3, at least 5, at least 10, at least 25, at least 50, at least 100, at least 250, at least 500, at least 750, and / or no more than 1000, no more than 750, no more than 500, no more than 250, no more than 100, no more than 50, no more than 25, no more than 10, no more than 5, no more than 3, no more than 2, or less. Combinations of the above-referenced ranges are possible (e.g., at least 1 and no more than 1000, at least 2 and no more than 1000). Other ranges are also possible. In one set of embodiments, the array of posts comprises a single row of post and / or sub-channels. Referring to FIG.2A as a non-limiting example, the array of posts 120 comprises multiple rows of posts and sub-channels, e.g., as exemplified by row numbers ni, ni+1,ni+2, etc. In some embodiments, the array of posts may comprise m number of post(s) and / or sub- channels per row, where m is at least 1, at least 2, at least 3, at least 5, at least 10, at least 25, at least 50, at least 100, at least 250, at least 500, at least 750, and / or no more than 1000, no more than 750, no more than 500, no more than 250, no more than 100, no more than 50, no more than 25, no more than 10, no more than 5, no more than 3, no more than 2, or less. Combinations of the above-referenced ranges are possible (e.g., at least 1 and no more than 1000, at least 2 and no more than 1000). Other ranges are also possible. In one set of embodiments, the array of posts comprises a single post per row. While FIG.2A illustrates an embodiment in which the fluidic channel 110 comprises one or more posts, it should be understood that the disclosure is not so limited, and that in certain embodiments, a fluidic channel in a device does not necessarily include a post therein. FIG.1A can be used to illustrate one such embodiment. As shown, fluidic channel 110a does not contain any posts therein. As shown, in accordance with certain embodiments, the fluidic channel 110a comprise a single sub-channel 130d therein formed between extruded wall portions of the fluidic channel. The sub-channel 130d may have any properties (e.g., minimum cross-sectional dimension) described respective to the sub-channels shown in FIG.2A. The one or more posts within the fluidic channel may individually have any of a variety of appropriate shapes and forms. If more than one post is present, the posts may have the same or different shapes and / or sizes. In some embodiments, at least one of the plurality of posts comprises a shape such as kite-shaped, a hexagon, rectangular, circular, triangular, polygonal, etc. For example, FIG.2A can be used to illustrate a plurality of posts within the fluidic channel 110 having a kite-shaped structure. As another example, FIG.6 can be used to illustrate a plurality of posts having hexagonal shapes. Other shapes are also possible. In some embodiments, at least some of the sub-channel(s) (for example, defined between two neighboring posts) may have an inlet portion, an outlet portion, and a constriction portion between the inlet portion and outlet portion. In some cases, the constriction portion may of the sub-channel(s) may have a cross-sectional dimension that is less than those of the inlet portion and outlet portion. FIG.2A can be used to illustrate one such embodiment. For example, as shown in FIG.2A, a sub-channel defined by neighboring posts may include an inlet portion a, an outlet portion c, and a constriction portion b therebetween, with the constriction portion b having a cross-sectional dimension less than the inlet and outlet portions. In some embodiments, at least one or more (e.g., some) of the sub-channel(s) have a minimum cross- sectional dimension w in the constriction portion of the sub-channel(s), e.g., as shown in FIG. 2D. In some embodiments, the minimum cross-sectional dimension of the sub-channel(s) may be sized so as to allow denudation of a target entity of interest (e.g., an oocyte), e.g., such as having size(s) comparable to (or slightly larger) than the size of the target entity (e.g., oocyte). In some embodiments, some (or all) of the sub-channel(s) within the denuder region may have a minimum cross-sectional dimension w of greater than or equal to 20 micrometers, greater than or equal to 50 micrometers, greater than or equal to 70 micrometers, greater than or equal to 80 micrometers, greater than or equal to 100 micrometers, greater than or equal to 120 micrometers, greater than or equal to 125 micrometers, greater than or equal to 130 micrometers, greater than or equal to 140 micrometers, greater than or equal to 150 micrometers, greater than or equal to 160 micrometers, greater than or equal to 170 micrometers, greater than or equal to 180 micrometers, greater than or equal to 200 micrometers, greater than or equal to 250 micrometers, greater than or equal to 300 micrometers, and / or less than or equal to 350 micrometers, less than or equal to 300 micrometers, less than or equal to 250 micrometers, less than or equal to 200 micrometers, less than or equal to 180 micrometers, less than or equal to 170 micrometers, less than or equal to 160 micrometers, less than or equal to 150 micrometers, less than or equal to 140 micrometers, less than or equal to 130 micrometers, less than or equal to 125 micrometers, less than or equal to 100 micrometers, less than or equal to 80 micrometers, less than or equal to 70 micrometers, less than or equal to 50 micrometers, or less. Combinations of the above-referenced ranges are possible (e.g., between 80 micrometers and 350 micrometers, between 70 micrometers and 350 micrometers, between 120 micrometers and 180 micrometers, between 150 micrometers and 180 micrometers, between 120 micrometers and 160 micrometers, or between 120 micrometers and 150 micrometers). Other ranges are also possible. In some embodiments, the minimum cross-sectional dimension of the sub-channels in the denuder region may depend, at least in part, on the type of target entity that is being denuded in the denuder region. As described elsewhere herein, the target entity may be an oocyte. Depending on the particular type of oocyte (e.g., human oocyte, bovine oocyte, mouse oocyte), the size of the oocyte may also vary. In some embodiments, at least some of the sub- channels in the denuder region may have a minimum cross-sectional dimension that is at least 1.01 times (at least 1.1 times, at least 1.15 times, at least 1.2 times, at least 1.25 times, at least 1.3 times, at least 1.4 times, at least 1.5 times, or more, and / or up to 3 times, up to 2.5 times, up to 2 times, up to 1.5 times, up to 1.4 times, up to 1.3 times, up to 1.25 times, up to 1.2 times, up to 1.15 times, up to 1.1 times, etc.) the size (e.g., diameter) of the target entity (e.g., a bare oocyte). However, in some cases, the minimum cross-sectional dimension of the sub-channels may also be slightly smaller than the target entity (e.g. a bare oocyte). For example, at least some of the sub-channels in the denuder region may have a minimum cross-sectional dimension that is at least 0.8 times, at least 0.82 times, at least 0.85 times, at least 0.87 times, at least 0.9 times, at least 0.92 times, at least 0.94 times, at least 0.95 times, at least 0.96 times, at least 0.97 times, at least 0.98 times, at least 0.99 times, etc. and / or up to 0.99 times, up to 0.98 times, up to 0.97 times, up to 0.96 times, up to 0.95 times, up to 0.94 times, up to 0.92 times, up to 0.9 times, up to 0.87 times, up to 0.85 times, up to 0.82 times, up to 0.8 times the size (e.g., diameter) of the target entity (e.g., a bare oocyte). Without wishing to be bound by any theory, it is believed that slightly smaller dimensions may artificially activate oocytes, and / or induce proliferation towards embryo growth. In some embodiments, the dimensions referenced above may be particularly advantageous for applications directed to oocyte denudation. However, it should be understood that the disclosure is not so limited, and that in some embodiments, the minimum cross- sectional dimension of the sub-channels in the denuder region may be scaled relative to the size of the target entity (e.g., a cell, a tissue, etc.). For example, in some embodiments in which the target entity is a particular type of cell (e.g., a tumor cell), the minimum cross-sectional dimension of the sub-channels be in the size range of micrometers, such as less than 100 microns, less than 50 microns, less than 25 microns, less than 20 microns, less than 15 microns, or less and / or down to 10 microns, down to 5 microns, or less. For example, in some embodiments in which the target entity is a particular type of tissue, the minimum cross- sectional dimension of the sub-channels be in the size range of millimeter, such as at least 0.5 mm, at least 1 mm, at least 2 mm, at least 10 mm, or more. In some embodiments, some of the sub-channels may have dimensions that differ from the rest of the sub-channels. For example, in certain embodiments, the sub-channels may be arranged such that the sub-channel(s) adjacent an inlet of the microfluidic device may have minimum cross-sectional dimension(s) larger than the minimum cross-sectional dimension(s) of sub-channel(s) further away from the inlet of the device. For example, referring to FIG.2A, the sub-channels 130 adjacent an inlet 150 of the device 100 (such as those in row ni) may have minimum cross-sectional dimension(s) larger than cross-sectional dimension(s) of sub- channel(s) further away from the inlet 150 of the device 100 (such as those in row ni+5). In some embodiments, the minimum cross-sectional dimension of the sub-channels furthest away from the inlet 201 (adjacent outlet 202) may have the smallest minimum cross-sectional dimension amongst the other sub-channels in the denuder region, such as having a minimum cross-section dimension that is comparable to the size of the target entity. In some embodiments, starting from a first row or set of sub-channels (e.g., s1) adjacent the inlet of the denuder region, each subsequent row or set of sub-channels (e.g., s2, s3) may have minimum cross-sectional dimensions that decrease by an increment of at least 5 micrometers (e.g., at least 10 micrometers, at least 15 micrometers, or more, and / or up to 20 micrometers, up to 25 micrometers) from the minimum cross-sectional dimensions of the preceding row or set of sub-channels. In some embodiments, such an arrangement in the denuder region may allow for gradual removal (e.g., denudation) of secondary entities from the target entities, which would lead to an overall more efficient denudation process. As an exemplary example, in embodiments in which the target entity is an oocyte, the incremental decrease in sub-channel dimensions may allow for gradual removal of non-oocyte cells (e.g., cumulus cells, corona cells, etc.) from the oocyte as the oocyte complex passes through each row or set of sub-channels. Depending on the particular application, the sub-channels in the denuder region may be sized that a desired level of denudation can be achieved, in some embodiments. For example, in applications in which complete denudation of secondary entities (e.g., non-oocyte cells) from the target entity (e.g., oocyte) is desired, at least some of the sub-channels (e.g., sub-channels in stage s3) may have minimum cross-sectional dimensions comparable or approximately equal to the size of the target entity. For another example, in applications in which partial denudation of secondary entities (e.g., non-oocyte cells) from the target entity (e.g., oocyte) is desired, at least some of the sub-channels (e.g., sub-channels in stage s3) may have minimum cross-sectional dimensions that are slightly larger than the size of the target entity. In some embodiments, the plurality of sub-channels may be divided into one or more stages, with some or all of the stages containing sub-channels having different minimum cross- sectional dimensions from the those in the other stage(s). For example, in some embodiments, the sub-channels may comprise a first stage of sub-channels having a minimum cross-sectional dimension of greater than 140 micrometers and less than or equal to 160 micrometers, a second stage of sub-channels having a minimum cross-sectional dimension of greater than 120 micrometers and less than or equal to 140 micrometers, a third stage of sub-channels having a minimum cross-sectional dimension of greater than 50 micrometers and less than or equal to 120 micrometers, etc. In some embodiments, the plurality of posts and / or sub-channels may be arranged such that a row of posts and / or sub-channels is offset from a subsequent row of posts and / or sub- channels, e.g., as shown in FIG.2A. For example, in one set of embodiments, the sub-channel may be arranged such that the longitudinal axis of sub-channel(s) in one row (such as those in row ni) of the fluidic channel passes through (or coincides with) the longitudinal axis of post(s) in a subsequent row (such as those in row ni+1). However, it should be understood the disclosure is not so limited, and that any appropriate arrangement / order of the posts and / sub- channels are possible. In some embodiments, at least a portion of the walls forming the sub-channels may comprises a plurality of extruded features (e.g., teeth). In some embodiments, the minimum cross-sectional dimension w of a sub-channel may correspond to a distance between the outermost edges (e.g., tips) of extruded features (e.g., teeth) on opposing walls of the sub- channel(s). For example, as shown in FIGS.2A-2E, at least a portion of the walls on the plurality of posts 120 defining the sub-channel(s)130 comprise extruded features (e.g., teeth) 140. As shown in FIG.2D, the minimum cross-sectional dimension w of the sub-channel may correspond to the distance between the outermost edges of extruded features 140 on respective walls of neighboring posts (e.g., post 120a, post 120b). Similarly, as shown in FIGS.1A-1B, at least a portion of the extruded wall portions of the fluidic channel 110a may comprise teeth, and the minimum cross-sectional dimension w may correspond to the distance between the tips of teeth on opposing walls of the fluidic channel. While FIGS.1A-2E show one set of embodiments in which the walls forming the sub- channels comprise a plurality of extruded features (e.g., teeth), it should be understood that the disclosure is not so limited, and that in other embodiments, at least one (or both) of the walls forming the sub-channels may be substantially smooth (e.g., lack of teeth thereon). In some embodiments, the sub-channel(s) and / or post(s) define a denuder region within the fluidic channel. The denuder region, according to some embodiments, is configured to facilitate denuding of target entities (e.g., oocytes) from bounded and / or associated secondary entities (e.g., bounded non-oocyte cells) as the target entities pass through sub-channel(s) within the denuder region. For example, as shown in FIG.2A, the region of fluidic channel 110 comprising the plurality of post(s) 120 and / or subchannel(s) 130 defines a denuder region 115. For another example, as shown in FIG.1A, the region of fluidic channel 110a comprising the subchannel 130d defines a denuder region 115a. The denuder region, according to some embodiments, may advantageously have a relatively small length. According to some embodiments, the length of denuder region may be measured horizontally across from the first (row of) sub-channel(s) or post(s) in the denuder region to the last (row of) sub-channel(s) or post(s) in the denuder region. FIGS.1A-2A can be used to illustrate this. For example, as shown in FIG.2A, the length L of the denuder region can be measured from the first row niof post(s) or sub-channel(s) to the last row ni+5of post(s) or sub-channel(s). As another example, as shown in FIG.1A, in embodiments in which a single sub-channel is present within the fluidic channel, the length of the single denuder region 115a would the same as the length of the sub-channel 130a itself. In some embodiments, the length of denuder region within the microfluidic device may be relatively short, such as at least 50 micrometers, at least 100 micrometers, at least 500 micrometers, at least 1 mm, at least 2 mm, at least 3 mm, at least 5 mm, at least 8 mm, at least 10 mm, at least 20 mm, at least 40 mm, at least 60 mm, at least 80 mm, at least 100 mm, at least 150 mm, and / or no more than 200 mm, no more than 150 mm, no more than 100 mm, no more than 80 mm, no more than 60 mm, no more than 40 mm, no more than 20 mm, no more than 10 mm, no more than 8 mm, no more than 5 mm, no more than 3 mm, no more than 2 mm, no more than 1 mm, no more than 500 micrometers, no more than 100 micrometers, or less. Combinations of the above-referenced ranges are possible (e.g., at least 10 mm and no more than 200 mm, at least 10 mm and no more than 100 mm, at least 20 micrometers and no more than 200 mm, at least 20 micrometers and no more than 200 mm, at least 50 micrometers and no more than 200 mm, or at least 50 micrometers and no more than 10 mm). Other ranges are also possible. Without wishing to be bound by any theory, it is believed that due to the ability to flow entities (such as oocytes) repeatedly through a denuder region, the length of the denuder region can be relatively short, as the effective length of the denuder region that the entities (e.g., cells) actually experience is the product of the length of the denuder region and the number of times that the entities pass therethrough (e.g., in one direction, or in more than one direction). In contrast, in many other systems, only a single pass of the entities through the denuder region is contemplated. However, it should be understood that the length of the denuder region is not limited to the above-referenced ranges, and that in some cases, the length of the denuder region may be longer, e.g., such as 10 cm or longer. In some embodiments, each of the sub-channel(s) in the denuder region described above may have a length of at least 50 micrometers, at least 100 micrometers, 200 micrometers, at least 500 micrometers, at least 1 mm, at least 2 mm, at least 4 mm, at least 10 mm, at least 20 mm, at least 50 mm, at least 100 mm, or more, and / or no more than 200 mm, no more than 100 mm, no more than 50 mm, no more than 20 mm, no more than 10 mm, no more than 5 mm, no more than 2 mm, no more than 1 mm, no more than 500 micrometers, no more than 200 micrometers, no more than 100 micrometers, or less. Combinations of the above-referenced ranges are possible (e.g., at least 200 micrometers and no more than 1 mm, at least 200 micrometers and no more than 10 mm, at least 200 micrometers and no more than 100 mm). Other ranges are also possible. In some cases, some (or all) of the sub-channel(s) comprise inlet portions and / or outlet portions that are tapered towards the constriction portions of the sub-channel(s). For example, as shown in FIG.2A, the inlet portion a and outlet portion b may be tapered into the constriction portion b of the sub-channel. In some cases, the presence of such tapered inlet and / or outlet portions may effectively direct bulk fluid flow into the sub-channel(s) from the inlet and / or outlet portion into the constriction portion, thereby facilitating denudation of target entities (e.g., oocyte) as they travel through the sub-channel(s). In embodiments in which the fluidic channels comprise posts, the post may have any of a variety of shapes (e.g., hexagonal, kite-like, etc. or other shapes such as those described herein) that can lead to formation of sub- channel(s) having tapered inlet and / or outlet portions, as described above. However, it should be understood that the present disclosure is not so limited, and that in certain embodiments, at least one or more of the inlet and / or outlet portions may not be tapered. As noted above, the sub-channel(s) may optionally be formed by one or more wall(s) (of neighboring posts) comprising teeth. In some cases, the presence of teeth on the wall(s) of the sub-channels may advantageously aid denudation of target entities (e.g., oocyte complexes) and they pass through the sub-channel(s). In embodiments in which a plurality of posts is present in the fluidic channel, the wall(s) of the sub-channel(s) are defined by neighboring pairs of posts, e.g., as shown in FIGS.2A-2E. In some cases, both opposing walls forming the sub-channel may comprise teeth. In other cases, only one of the opposing walls forming the sub-channel may comprise teeth. In some cases, at least a portion on the posts 120 forming the walls of inlet portion a, constriction portion b, and outlet portion c of the sub-channel(s) comprises teeth. In some cases, the constriction portion b of the sub-channel(s) comprises teeth. In some cases, the inlet portion a and / or outlet portion c of the sub-channel(s) comprises teeth. The teeth on the post(s) and / or wall(s) of the sub-channel(s) may have any of a variety of appropriate shapes, including, but not limited to, round, triangular, rectangular, saw-teeth, quadrilaterals, and / or other polygonals. While FIG.2A illustrate one embodiment of posts comprising teeth that are saw-teethed, it should be understood that the disclosure is not so limited, and that in other embodiments, the teeth may have other shapes. For example, FIGS. 7A-7B can be used to illustrate various shapes of teeth on the post(s) and / or wall(s) of the sub- channel(s), such as saw-teeth (FIG.7A), rectangular (FIG.7B), triangular (FIG.7C), and circular (FIG.7D). In some embodiments, in may be particularly advantageous for the teeth on the post(s) to have one or more sharp features (e.g., an edge, a corner, a point, a tip, etc.). The presence of these sharp features in the teeth may allow for more efficient denudation of secondary entities from the target entity (by inducing tear and disruption of the secondary entities) and as the target entity gains contact with these features. Non-limiting example of teeth on posts and / or walls having one or more sharp features include saw-teeth, rectangular, triangular, as shown in FIG.2D and / or FIGS.7A-7C. The teeth on the post(s) and wall(s) may have any of a variety of appropriate dimensions and / or orientations. For example, as shown in FIGS.7A-7C, the teeth may comprises a first length (e.g., LFEAT-1), a second length (e.g., LFEAT-3), a first height (e.g., LFEAT-2), a second height (e.g., LFEAT-4), a first angle (αFEAT-1), and a second angle (e.g., αFEAT-2). The first length (e.g., LFEAT-1), may have any of a variety of values, such at between 5 micrometers and 30 micrometers, between 10 micrometers and 20 micrometers, or between 15 micrometers and 30 micrometers. The second length (e.g., LFEAT-3) may have any of a variety of values, such at between 0 micrometers and 30 micrometers, between 10 micrometers and 20 micrometers, or between 15 micrometers and 30 micrometers. The first height (e.g., LFEAT-2) may have any of a variety of appropriate values, such as between 30 micrometers and 80 micrometers, between 40 micrometers and 60 micrometers, or between 50 micrometers and 80 micrometers. The second height (e.g., LFEAT-4) may have any of a variety of appropriate values, such as between 10 micrometers and 50 micrometers, between 20 micrometers and 40 micrometers, or between 30 micrometers and 50 micrometers. In some embodiments, the angles (αFEAT-1,2) can be between 20 degrees and 80 degrees, or 30 degrees and 60 degrees, Other ranges are possible. For example, in some cases, the length of the feature sides (LFEAT-1,2,3,4) can be as small as 1 µm and as large as 1000 µm. In some embodiments, the angles (αFEAT-1,2) can be as small as 0.1° and as large as 179.9°. In one example, the extruded featured may be triangular shaped and may have the following geometrical parameters: LFEAT-3= 0. In another example, the extruded features may be rectangular shaped and may have the following parameters: LFEAT-2 = LFEAT-4, and αFEAT-1 = αFEAT-2. In yet another example, the extruded featured may be circular shaped and the features may be defined by the circle radius (RFEAT), the offset of its center from the wall (LOFFSET), and the distance between features (LFEAT), as shown in FIG.7D. The teeth on the one or more wall(s) of the sub-channel(s) may be oriented in any of a variety of appropriate directions. In some cases, it may be particularly advantageous to have some teeth oriented towards a direction facing a bulk fluid flow across the fluidic channel, as this may lead to an increase in denudation efficiency of target entities as they enter the sub- channel(s). In some embodiments, the teeth may be oriented at any angle, such as being saw- teethed, e.g., as shown in FIGS.2A-2E. In some cases, according to some embodiments, the teeth on one or more wall(s) of the sub-channel may be unidirectional. For example, as shown in FIG.2A, the teeth 140 on the posts 120a and / or 120b may be oriented facing a first direction 12 of bulk fluid flow through the sub-channel(s). In some cases, the teeth on one or more wall(s) of the sub-channel may be bi-directional, such as comprising a first set of teeth that is oriented facing a first direction of bulk fluid flow across the sub-channel, and a second set of teeth that is oriented facing a second direction of bulk fluid flow across the sub-channel, e.g., as shown in FIG.6. As shown, in the constriction portion of the sub-channel between neighboring pair of posts, each of the opposing walls comprise a first set of teeth that is oriented facing a forward fluid flow through the sub-channel and a second set of teeth that is oriented facing a backward fluid flow through the sub-channel. The first set of teeth may be oriented at any of a variety of appropriate angles facing a first direction of bulk fluid flow across the sub-channel. For example, the first set of teeth may be oriented at an angle between 0.1° and 90°, between 5° and 80°, between 20° and 70°, or between 30° and 60° facing the bulk fluid flow across the sub-channel. In some cases, the second set of teeth may be oriented in a direction that is substantially opposite to the first set of teeth. For example, the second set of teeth may have a tip that is oriented in a direction that is at least 5 degrees, at least 10 degrees, at least 20 degrees, at least 30 degrees, at least 35 degrees, at least 40 degrees, at least 45 degrees, at least 60 degrees, at least 70 degrees, at least 90 degrees, or more, and / or up to 120 degrees, up to 140 degrees, up to 160 degrees, or up to 179 degrees, or up to 179.9 degrees clockwise from the tip of the first set of teeth. Combinations of the above-referenced ranges are possible (e.g., at least 5 degrees and up to 179.9 degrees, or at least 30 degrees and up to 160 degrees). Other ranges are also possible. Without wishing to be bound by any particular theory, the presence of bi-directional teeth may advantageously enhance denudation efficiency compared to unidirectional teeth during oscillatory flow, under otherwise identical conditions. Combinations of different configurations of size, shapes and directionality may be used from the above to facilitate denudation. In some embodiments, the microfluidic device comprises a first pressure source upstream of the denuder region containing the plurality of posts and a second pressure source downstream of the denuder region. In some embodiments, the device further comprises a first inlet adjacent and connected to the first pressure source and a second inlet adjacent and connected to the second pressure source. In some embodiments, the first pressure source and / or second pressure source independently comprises one or more pumps (e.g., syringe pumps, peristaltic pumps, positive displacement pumps, etc.). As described elsewhere herein, the presence of at least two pressure sources may advantageously allow for oscillatory flow across the fluidic channel, such as causing flow across the denuder region containing the plurality of posts and sub-channels in the first direction and in the second direction. For example, the first pressure source, according to some embodiments, may be configured exert pressure in a first direction, such that a fluid within the fluidic channel may be caused or induced to flow in the first direction within the device. Conversely, according to some embodiments, the second pressure source may be configured to exert a pressure in a second direction, such that the fluid within the fluidic channel may be caused or induced to flow in the second direction. FIG.2A can be used to illustrate one such embodiment. As shown, the microfluidic device 100 comprises a first inlet 150 and a second inlet 160. In some cases, the first inlet 150 may be positioned adjacent and connected to a first pressure source 155 and the second inlet 160 may be positioned adjacent and connected to a second pressure source 165. The first pressure source 155, according to some embodiments, may be configured exert pressure in a first direction, such that a fluid within the fluidic channel (e.g., denuder region) may flow in the first direction 12 (e.g., a forward direction). Conversely, according to some embodiments, the second pressure source 165 may be configured to exert a pressure in a second direction, such that the fluid within the fluidic channel may flow in the second direction 14 (e.g., a reverse direction). In some embodiments, the microfluidic device comprises a capture region positioned downstream of a denuder region of the fluidic channel containing the post(s) and / or sub- channel(s). In some cases, according to some embodiments, the capture region may be disposed between the first inlet and the second inlet of the microfluidic device. For example, referring to FIG.2A, the microfluidic device 100 may further comprise a capture region 172 positioned downstream of the denuder region 115 containing the posts 120 and / or sub-channels 130 and between the first inlet 150 and the second inlet 160. The capture region may comprise a plurality of posts, in some embodiments. The plurality of posts, in some cases, may be spaced apart such that a plurality of sub-channel(s) are defined between neighboring pairs of posts. The plurality of sub-channels between the posts in the capture region may have a minimum cross-sectional dimension that is less than the minimum cross-sectional dimension of the sub-channel(s) within the denuder region of the fluidic channel, according to some embodiments. In some embodiments, the plurality of sub- channels in the capture region may be sized to only allow denuded entities (e.g., denuded or bare oocytes without the bound non-oocyte cells) to flow readily therethrough while trapping larger target complexes (e.g., oocyte complex) and / or debris. For example, referring again to FIG.2A, the capture region 172 of the device may comprise a plurality of posts 175 defining a plurality of sub-channels 177 between neighboring pairs of posts. In some cases, the first pressure source 155 may be positioned upstream of the capture region 172 containing the posts 175, and the second pressure source 165 may be positioned downstream of the capture region 172. One or more outlets, such as a first outlet 170, may be positioned downstream of the capture region 172. Alternatively or additionally, a second outlet may be positioned upstream of the capture region 172, such as between the denuder region and the capture region, as shown in FIG.9B. In some embodiments, some (or all) of the sub-channel(s) within the capture region of the fluidic channel may have a minimum cross-sectional dimension d (e.g., as shown in FIG.5) of greater than or equal to 30 micrometers, greater than or equal to 40 micrometers, greater than or equal to 50 micrometers, greater than or equal to 65 micrometers, greater than or equal to 80 micrometers, greater than or equal to 90 micrometers, greater than or equal to 100 micrometers, greater than or equal to 110 micrometers, greater than or equal to 120 micrometers, greater than or equal to 130 micrometers, greater than or equal to 140 micrometers, and / or less than or equal to 150 micrometers, less than or equal to 140 micrometers, less than or equal to 130 micrometers, less than or equal to 120 micrometers, less than or equal to 110 micrometers, less than or equal to 100 micrometers, less than or equal to 90 micrometers, less than or equal to 80 micrometers, less than or equal to 65 micrometers, less than or equal to 50 micrometers, less than or equal to 40 micrometers, or less. Combinations of the above-referenced ranges are possible (e.g., greater than or equal to 30 micrometers and less than 120 micrometers, greater than or equal to 30 micrometers and less than or equal to 100 micrometers, greater than or equal to 30 micrometers and less than 80 micrometers, greater than or equal to 120 micrometers and less than or equal to 150 micrometers, or greater than or equal to 80 micrometers and less than or equal to 120 micrometers, or between 50 micrometers and 150 micrometers). Other ranges are also possible. In one set of embodiments, some (or all) of the sub-channel(s) within the capture region of the fluidic channel may have a minimum cross-sectional dimension d of less than or equal to 120 micrometers. In some embodiments, the above-referenced ranges may be particularly advantageous for certain type of applications, e.g., denudation of oocyte complexes. However, it should be understood that the disclosure is not so limited, and that in some embodiments, depending on the application, the minimum cross-sectional dimension of the sub-channels in the capture region may be scaled relative to the size of the target entity (e.g., a cell, a tissue, etc.). For example, in some embodiments in which the target entity is a particular type of cell (e.g., a tumor cell), the minimum cross-sectional dimension of the sub-channels be in the size range of micrometers, such as less than 100 microns, less than 50 microns, less than 25 microns, less than 20 microns, less than 15 microns, or less and / or down to 10 microns, down to 5 microns, or less. For example, in some embodiments in which the target entity is a particular type of tissue, the minimum cross-sectional dimension of the sub-channels be in the size range of millimeter, such as at least 0.5 mm, at least 1 mm, at least 2 mm, at least 10 mm, or more. In some embodiments, at least some (or all) of the sub-channels in the capture regions have a dimension sized such that a fully denuded (or dissociated) target entity (e.g., an oocyte) cannot pass therethrough when subjected to flow. For example, according to some embodiments, at least some (or all) of the sub-channels in the capture regions may have a size that is at least 10 micrometers, at least 20 micrometers, at least 30 micrometers, at least 40 micrometers, and / or up to 50 micrometers, at least 60 micrometers, at least 80 micrometers, or up to 100 micrometers, or more, smaller than the size (e.g., diameter) of the fully denuded (or dissociated) target entity. In some cases, according to some embodiments, at least some (or all) of the sub-channels in the capture regions may have a size that is at least 10%, at least 20%, at least 30%, at least 40%, or more, and / or up to 50%, up to 60%, up to 70%, or up to 80% less than the size of a fully denuded (or dissociated) target entity. In some embodiments, the sub-channel(s) between the posts in the capture region may have a minimum cross-sectional dimension that is less than the minimum cross-sectional dimension of the sub-channel(s) within the denuder region of the fluidic channel, according to some embodiments. For example, the sub-channel(s) between the posts in the capture region may have minimum cross-sectional dimensions that are at least 10 micrometers (e.g., at least 20 micrometers, at least 30 micrometers, at least 40 micrometers, at least 50 micrometers, and / or up to 50 micrometers, up to 70 micrometers, up to 100 micrometers, up to 120 micrometers, up to 150 micrometers, or more) less than the minimum cross-sectional dimension of the sub- channel(s) in the denuder region. In some embodiments, the plurality of sub-channels in the capture region may be sized to only allow denuded entities (e.g., denuded or bare oocytes without the bound non-oocyte cells) to flow readily therethrough while trapping larger target complexes (e.g., oocyte complex) and / or debris. The plurality of posts within the capture region may be arranged in any appropriate manner or combination, such as an array of posts, a row of posts, etc. In some cases, the capture region may comprise a row of posts that spans a cross-section of the fluidic channel, such as shown in FIG.2A. In some cases, the capture region 172 may have an overall width that is larger than the denuder region 115, e.g., such as at least 2 times (or at least 5 times, at least 10 times, at least 20 times) larger than the denuder region. The plurality of posts within the capture region may have any of a variety of appropriate shapes, including but not limited to, triangles, polygons, and / or any other shapes described elsewhere herein with respect to the posts in the denuder region. In some cases, the plurality of posts may have smooth surfaces. In some cases, the plurality of posts may have surfaces comprising teeth, as described elsewhere with respect to the posts in the denuder region. While FIG.2A illustrates an embodiment in which the device comprises a capture region, it should be understood that the disclosure is not so limited, and that in certain embodiments, the fluidic channel 110 does not include capture region therein. FIG.9C can be used to illustrate one such embodiment. As shown, the device does not contain any capture region therein. In some embodiments, the microfluidic device further comprises one or more outlets configured to output one or more denuded target entities (e.g., oocytes) from the microfluidic device. The outlet may be positioned downstream of the denuder region of the fluidic channel comprising a plurality of posts and / or sub-channels, according to some embodiments. In embodiments in which a capture region is present in the microfluidic device, one or more outlet may be positioned downstream and / or upstream of the capture region, as described in more detail below. For example, referring to FIG.2A, the microfluidic device 100 comprises an outlet 170 positioned downstream of the denuder region 115 in the fluidic channel 110 containing the plurality of posts 120 and / or sub-channels 130. In some cases, the outlet 170 may be further positioned downstream the capture region 172. While FIG.2A illustrates an embodiment in which the outlet is positioned downstream of the capture region, it should be understood that the disclosure is not so limited, and that in certain embodiments, the outlet may be disposed upstream of the capture region. For example, as shown in FIG.9B, a first outlet may be disposed upstream of the capture region, while a second outlet may be disposed downstream of the capture region. In some embodiments, the method comprises causing a first flow in a first direction from an inlet (e.g., inlet 1) of the fluidic channel to one or more outlet of the fluidic channel (e.g., outlet 1 or outlet 2). In some embodiments, the method comprises further causing a second flow in a second direction from either the first and / or the second outlet to the inlet of the fluidic channel. In one set of embodiments, the outlet may be in fluidic communication with a collection region. In some cases, the collection region may be a region for collecting oocytes or other target cells. For example, the collection region may comprise one or more wells for collecting an oocyte. The wells may be positioned to allow imaging, e.g., using a camera or a microscope. This may be useful, for example, for examining or selecting oocytes or other target cells. In some embodiments, the microfluidic device may further comprise one or more fluid controls, e.g., valves, switches, actuators, and the like. Specific non-limiting examples of one or more fluid controls include pinch valve, butterfly valve, gate valves, ball valves, plug valves, PDMS valve, quake valve, elastic deformation based valves, piezo valves, and / or pneumatic valves. In some embodiments, the fluid controls may be a solenoid actuated valve. The one or more fluid controls may be arranged to control the one or more pressure sources, inlets and / or outlets of the device. In one set of embodiments, the one or more fluid controls may be disposed between the first pressure source and the first inlet and / or between the second pressure source and the second inlet. As such, the one or more fluid controls may be employed to control connectivity between the pressure source(s) and the inlet(s) and modulate flow directionality of fluids within the device. FIG.2A can be used to illustrate one such embodiment. For example, as shown in FIG. 2A, a fluid control 180 may be disposed between the second inlet 160 and the second pressure source 165. When in a first position (e.g., open position), the fluid control 180 may allow the second pressure source 165 to connect with the second inlet 160, such that a pressure may be applied by the second pressure source 165 to cause fluid flow in the device in the second direction 14. When in a second position (e.g., closed position), the fluid control 180 may disconnect the second pressure source 165 from the second inlet 160, such that the fluid flow within the device is no longer be affected by the second pressure source. Similarly, in some cases, a fluid control 182 may be disposed between the first inlet 150 and the first pressure source 155. Such a fluid control may be employed to modulate connectivity between the first inlet and the first pressure source and to control fluid flow in the first direction 12 in the channel. While FIG.2A illustrates an embodiment in which fluid controls are disposed between the various inlets and pressure sources, it should be understood that the disclosure is not so limited, and that in certain embodiments, one or more fluid controls may be disposed adjacent the one or more outlets (e.g., outlet 170) to control the opening and closing of the outlets (based on a command received from a controller and / or processor), according to some embodiments. The microfluidic device described herein may further comprise a controller (e.g., a closed loop controller), according to some embodiments. The controller, in some cases, may be configured to selectively actuate one or more components, e.g., the one or more pressure sources, one or more inlets and / or outlets, and / or the various fluid control valves, based on one or more measured parameter within the device. Non-limiting examples of measured parameters include a denudation level of a target entity (e.g., oocyte) within the device, various fluid flow properties (e.g., directionality of fluid flow, flow rate), and / or number of rounds of repeated flow (e.g., oscillatory flow) across the fluidic channel (e.g., denuder region) containing the plurality of posts and / or sub-channels. The device may further comprise one or more sensors and / or detectors (e.g., image detector) configured to measure the one or more parameters, and one or more processors configured to relay a signal from the sensors and / or detectors to the controller, and vice versa. As a non-limiting example, referring to FIG.2A, in one set of embodiments, a controller 190 may be configured to selectively actuate one or more fluid control valves, such as the fluid controls 180 and 182 shown in FIG.2A, or the various fluid controls adjacent the one or more outlets (shown in FIG.9B). For example, the controller, in some embodiments, may selectively actuate the fluid controls 180 and / or 182 from a first position, e.g., a closed state, to a second position, e.g., an open state, such that fluids in the device may be caused to flow in the direction 14 or 12 in response to a pressure exerted by the pressure sources 165 or 155. The fluidic channel described herein may have any appropriate height. For example, the fluidic channel may have a height of at least 50 micrometers, 100 micrometers, at least 350 micrometers, at least 500 micrometers, at least 1,000 micrometers, at least 2,500 micrometers, at least 5,000 micrometers, and / or no more than 10,000 micrometers, no more than 5,000 micrometers, no more than 2,5000 micrometers, no more than 1,000 micrometers, no more than 500 micrometers, no more than 350 micrometers, no more than 100 micrometers, or less. Combinations of the above-referenced ranges are possible (e.g., at least 50 micrometers and no more than 350 micrometers, at least 50 micrometers and no more than 500 micrometers, or at least 50 micrometers and no more than 10,000 micrometers ). Other ranges are also possible. Certain aspects of the disclosure are directed to methods of denuding a target entity from one or more bounded secondary entities. In one set of embodiments, the target entity is an oocyte, and the one or more bounded secondary entities include one or more types of secondary cells (i.e., non-oocyte cell(s)) bounded to (e.g., surrounding or attached to) the oocyte, including, but not limited to, cumulus cells, granulosa cells, mural cells, thecal cells, red blood cells, or combinations thereof. In some cases, the secondary or non-oocyte cells, when removed, may be discarded as waste, used for diagnostic analysis, stored for later use, or the like. In some instances, methods of the denuding an oocyte complex comprising an oocyte and non-oocyte cells to separate the oocyte from the non-oocyte cells are described. As described in more detail below, one or more methods described herein may involve the use of oscillatory fluid flow within a microfluidic device for denudation of oocytes contained within a fluid sample. The fluid sample containing the oocyte may include any of a variety of types of fluids, including, but not limited to, follicular fluid, fluid containing ovarian tissue, fluid containing inseminated oocyte complexes, and / or any other fluid containing other tissues and / or debris in addition to the oocyte. The fluid may also include cell culture media in some embodiments. For example, in the fluid sample, the oocyte may be surrounded by or bounded to one or more layers of secondary entities, such as one or more layers of cumulus cells and / or granulosa cells, to form secondary entity bounded oocyte complex, such as cumulus oocyte complex (COC). The fluid sample may be derived from any of a variety of mammals, including, but not limited to, human, mouse, bovine, porcine, goat and / or ovine. The fluid may also be a type of culture media used to store, transport or hold tissues prior to the procedure. The oocyte and / or cumulus oocyte complex may have any of a variety of sizes described herein, depending on the type of mammal. In some embodiments, the method comprises causing repeating or oscillatory flow within a fluid channel. For example, certain embodiments are directed to causing a first flow of the fluid containing one or more oocyte complexes in a first direction through a fluidic channel. In some embodiments, a first flow of fluid in a first direction may correspond to a fluid flowing in a direction from an inlet of the fluidic channel, through the denuder region comprising post(s) and / or sub-channel(s), towards the outlet of the fluidic channel. The fluidic channel may have any of a variety of properties described herein, e.g., such as the fluidic channel 110 or 110a illustrated in FIGS.1A-2. The sub-channel(s) within the denuder region may comprise one of more features (e.g., teeth, constriction portion having a certain minimum cross-sectional dimension, tapered inlet and outlet portions) that aid denudation of oocyte during oscillatory flow. FIG.1A and FIG.2D can be used to illustrate a fluid flow in a first direction. As noted above, the denuder region may comprise a single sub-channel as shown in FIG.1A, or a plurality of sub-channel(s) defined between neighboring posts as shown in FIG.2D. As shown in FIG.1A, a first flow of a fluid containing one or more oocyte complexes 18 may be caused in a first direction 12 through a fluidic channel 110a from the inlet 150a of the fluidic channel, through the sub-channel 130a in the denuder region 115a, to the outlet 170a of the fluidic channel. As shown, the one or more oocyte complexes 18 may comprise an oocyte 18a surrounded at least partially by a plurality of non-targe secondary entities 18b (e.g., non-oocyte cells). Similarly, as shown in FIG.2D, a first flow of a fluid containing one or more oocyte complexes 18 may be caused to flow in a first direction 12 through from an inlet 150 of the fluidic channel, through some of the sub-channels 130 defined by neighboring pairs of posts 120 in the denuder region 115, to an outlet 170 of the fluidic channel. As the fluid containing the oocyte complex is caused to flow through the fluidic channel in the first direction, according to some embodiments, at least a portion of the bounded non- oocyte cells is removed or separated from the complex as the complex flows through the fluidic channel in the first direction. In some cases, at least 1%, at least 5%, at least 10%, at least 20%, and / up to 30%, up to 40%, up to 50%, up to 60%, up to 70%, up to 80%, or up to 9050%, up to 95%, up to 99%, or up to 100%, of the bounded non-oocyte cells is removed as the oocyte complex flows through the fluidic channel in the first direction. For example, referring to FIG. 1A and FIG.2D, at least a portion of the bounded non-oocyte cells 18b is removed as the oocyte complex 18 flows through the fluidic channel (e.g., 110 or 110b) containing the sub- channel(s) (e.g., 130 or 130a) in the first direction 12. In some embodiments, the method comprises causing a second flow of the fluid containing the one or more cumulous oocyte complex in a second direction through the fluidic channel. In some embodiments, a second flow of fluid in a second direction may correspond to a flow in a reverse direction, such as from the outlet of the fluidic channel, through the denuder region comprising post(s) and / or sub-channel(s), towards the inlet of the fluidic channel. For example, referring to FIG.1B, a second flow of a fluid containing one or more oocyte complexes 18 may be caused to flow in a second direction 14 from the outlet 170a of the fluidic channel, through the sub-channel 130a, to the inlet 150a of the fluidic channel. Similarly, referring to FIG.2E, a second flow of a fluid containing one or more oocyte complexes 18 may be caused to flow in a second direction 14, from the outlet 170 of the fluidic channel, through some of the sub-channels 130 in the denuder portion 115, to the inlet 150 of the fluidic channel. In some embodiments, the second direction may be substantially opposite to the first direction. For example, a flow having the second direction may be oriented in a direction that is greater than 90 degrees, greater than or equal to 120 degrees, greater than or equal to 140 degrees, greater than or equal to 160 degrees, greater than or equal to 180 degrees, greater than or equal to 200 degrees, greater than or equal to 220 degrees, greater than or equal to 240 degrees, and / or less than 270 degrees, less than or equal to 240 degrees, less than or equal to 220 degrees, less than or equal to 200 degrees, less than or equal to 180 degrees, less than or equal to 160 degrees, less than or equal to 140 degrees, or less than or equal to 120 degrees from the first direction of the first fluid in the clockwise direction. Combinations of the above- referenced ranges are possible (e.g., greater than 90 degrees and less than 270 degrees). In some embodiments, the second direction may be directly opposite the first direction, e.g., oriented about 180 degrees clockwise from the first direction. As the fluid containing the oocyte complex is caused to flow through the fluidic channel in the second direction, according to some embodiments, at least a portion of the bounded non- oocyte cells is removed or separated from the complex as the complex flows through the fluidic channel (e.g. denuder portion) in the second direction. In some cases, at least 1%, at least 5%, at least 10%, at least 20%, and / up to 30%, up to 40%, or up to 50% of the bounded non-oocyte cells is removed as the oocyte complex flows through the fluidic channel in the second direction. For example, as shown in FIG.1B and FIG.2E, at least a portion of the bounded non-oocyte cells 18b is removed as the oocyte complex 18 flows through the fluidic channel (e.g., 110 or 110b) containing the sub-channel(s) (e.g., 130 or 130a) in the second direction 12. In some embodiments, the first and / or second flow may be caused by a pressure exerted by one or more pressure sources. For example, the first flow may be caused by a pressure exerted by a first pressure source to flow in a first direction, and the second flow may be caused by a pressure exerted by a second pressure source to flow in a second direction, according to some embodiments. For example, referring to FIGS.1A-2E again, the first flow may be caused to flow in the first direction 12 by a first pressure exerted by a first pressure source (e.g., pressure source 155 shown in FIG.2A), and the second flow may be caused to flow in the second direction 14 by a second pressure exerted by a second pressure source (e.g., second pressure source 165 shown in FIG.2A), according to some embodiments. The first pressure and / or second pressure exerted by the pressure sources may have of a variety of values. For example, in some embodiments, the first pressure and / or second pressure may have a value of at least at least 0.01 psi, at least 0.05 psi, at least 0.1 psi, at least 0.5 psi, at least 1 psi, at least 2 psi, at least 5 psi, at least 10 psi, at least 20 psi, at least 50 psi and / or up to 100 psi, up to 200 psi, up to 300 psi, up to 400 psi, up to 500 psi, or more. Combinations of the above-referenced ranges are possible (e.g., at least 0.5 psi and up to 500 psi, at least 1 psi and up to 300 psi). Other ranges are also possible. In some embodiments, the fluid containing the oocyte complex may be subjected to first flow and second flow through the fluidic channel repeatedly, e.g., in an alternating and / or periodic fashion. For example, the oocyte complex subjected to a round of first and second flow (e.g., as shown in FIGS.1A-1B or FIGS.2D-2E) may be further caused to flow through the denuder region of the fluidic channel via a second round of the first and second flow, e.g., as shown in FIGS.1A-1B or FIGS.2D-2E. The above-referenced process may be repeated for any number of times, such as at least 1 round, at least 2 rounds, at least 3 rounds, 5 rounds, at least 10 rounds, at least 20 rounds, at least 30 rounds, at least 50 rounds, at least 100 rounds, and / or up to 200 rounds, up to 500 rounds, up to 1000 rounds, or more, of a first and second flow. Combinations of the above-referenced ranges are possible (e.g., at least 1 round and up to 1000 rounds, at least 5 rounds and up to 1000 rounds). Other ranges are also possible. The step of repeating a first flow and a second flow may be carried out at any of a variety of appropriate frequencies. In some embodiments, the repeating step may be carried out at a rate of at least 0.1 rounds of flow per minute, at least 1 round of flow per minute, at least 2 rounds of flow per minute, at least 4 rounds of flow per minute, at least 6 rounds of flow per minute, at least 8 rounds of flow per minute, at least 10 rounds of flow per minute, at least 20 rounds of flow per minute, at least 40 rounds of flow per minute, at least 60 rounds of flow per minute, at least 100 rounds of flow per minute, at least 500 rounds of flow per minute, at least 1,000 rounds of flow per minute, at least 5,000 rounds of flow per minute, or more, and / or no more than 10,000 rounds of flow per minute, no more than 5,000 rounds of flow per minute, no more than 1,000 rounds of flow per minute, no more than 500 rounds of flow per minute, no more than 100 rounds of flow per minute, no more than 60 rounds of flow per minute, no more than 40 rounds of flow per minute, no more than 20 rounds of flow per minute, no more than 10 rounds of flow per minute, no more than 8 rounds of flow per minute, no more than 6 rounds of flow per minute, no more than 4 rounds of flow per minute, no more than 2 rounds of flow per minute, no more than 1 round of flow per minute, or less, where one round of flow corresponds to a first flow in the first direction followed by a second flow in the second direction. Combinations of the above-referenced ranges are possible (e.g., at least 4 rounds of flow per minute and no more than 60 rounds of flow per minute, or at least 0.1 rounds of flow per minute and no more than 10,000 rounds of flow per minute). Other ranges are also possible. The first flow and / or second flow may have any of a variety of appropriate mean flow velocities. For example, in some embodiments, the first flow and / or second flow has a mean flow velocity of at least 0.01 cm / s, at least 0.1 cm / s, at least 1 cm / s, at least 5 cm / s, at least 10 cm / s, at least 12 cm / s, at least 15 cm / s, at least 20 cm / s, at least 24 cm / s, at least 30 cm / s, at least 50 cm / s, at least 100 cm / s, at least 500 cm / s, at least 1,000 cm / s, at least 5,000 cm / s, or more, and / or no more than 10,000 cm / s, no more than 5,000 cm / s, no more than 1,000 cm / s, no more than 500 cm / s, no more than 100 cm / s, no more than 50 cm / s, no more than 30 cm / s, no more than 24 cm / s, no more than 20 cm / s, no more than 15 cm / s, no more than 12 cm / s, no more than 10 cm / s, no more than 5 cm / s, no more than 1 cm / s, no more than 0.1 cm / s, or less. Combinations of the above-referenced ranges are possible (e.g., between 12 cm / s and 24 cm / s, between 0.01 cm / s and 50 cm / s, or between 0.01 cm / s and 10,000 cm / s). Other ranges are also possible. The first flow and the second flow may have mean flow velocities that are same or different, according to some embodiments. The first flow and / or second flow may have any of a variety of appropriate flow rates. For example, in some embodiments, the first flow and / or second flow has a flow rate of at least 0.01 mL / min, at least 0.1 mL / min, at least 1 mL / min, at least 2 mL / min, at least 5 mL / min, at least 10 mL / min, at least 15 mL / min, at least 50 mL / min, at least 100 mL / min, at least 500 mL / min, at least 1,000 mL / min, at least 5,000 mL / min, or more, and / or no more than 10,000 mL / min, no more than 5,000 mL / min, no more than 1,000 mL / min, no more than 500 mL / min, no more than 100 mL / min, no more than 50 mL / min, no more than 15 mL / min, no more than 10 mL / min, no more than 5 mL / min, no more than 2 mL / min, no more than 1 mL / min, no more than 0.1 mL / min, or less. Combinations of the above-referenced ranges are possible (e.g., between 0.01 mL / min and 1,000 mL / min, between 1 mL / min and 100 mL / min, between 2 mL / min and 1,000 mL / min, or between 5 mL / min and 15 mL / min). Other ranges are also possible. The first flow and the second flow may have flow rates that are same or different, according to some embodiments. The first flow and / or second flow may have any of a variety of appropriate duty cycles. The duty cycle may be measured as a percentage of time the fluid flows in one direction (e.g., first flow in a first direction or second flow in a second direction) during one round of oscillatory flow (e.g., one round of first flow and second flow). For example, a first flow in a first direction may have a duty cycle of at least 0.1%, at least 1%, at least 5%, at least 10%, at least 25%, at least 50%, at least 70%, at least 80%, at least 90%, and / or up to 95%, up to 97%, up to 99%, up to 99.5%, up to 99.9%. Combinations of the above-referenced ranges are possible (e.g., at least 0.1% and up to 99.9%, or at least 70% and up to 99.9%). Other ranges are also possible. To illustrate this, as a non-limiting example, a first flow in a first direction having duty cycle of 70% may correspond to a first flow moving in a first direction for 70% of the time, and a second flow moving in a second direction for 30% of the time, during one round of oscillatory flow. In some embodiments, the method comprises trapping the oocyte complex (or other entities) subjected to the first flow and / or second flow in a capture region comprising a plurality of posts defining a plurality of sub-channels between neighboring pairs of posts. For example, in one set of embodiments, when the oocyte complex is caused to flow through the denuder region containing the sub-channel(s) via a first flow in a first direction, the oocyte complex may become partially denuded and the partially denuded oocyte complex may be subsequently trapped by the sub-channels in the capture region. Upon trapping the partially denuded oocyte complexes, the trapped oocyte complexes may be caused to flow via a second flow in a second direction, such that the trapped oocyte complexes flow through the denuder region containing the sub-channel(s). The above-mentioned oscillatory flow may be repeated for any appropriate number of times, as described elsewhere herein. FIGS.2B-2C can be used to illustrate one such embodiment. For example, as shown in FIG.2B, as the oocyte complex is caused to flow (by a first applied pressure) through the denuder region 115 containing the sub-channel(s) 130 via the first flow in the first direction 12, the oocyte complex becomes at least partially denuded and may be subsequently trapped by the plurality of sub-channels 177 defined between neighboring pairs of posts 175 within the capture region 172. As shown in FIG.2C, in certain embodiments, upon trapping the oocyte complexes in the capture region 172, the trapped oocyte complexes may be caused to flow (by a second applied pressure) via the second flow in the second direction 14, such that the trapped oocyte complexes may again flow through the denuder region 115 containing the sub-channel(s) 130 for further denudation. In some embodiments, the method further comprises releasing the denuded oocyte when a measured parameter within the device reaches a threshold value. For example, the measured parameter may be a denudation level of the oocyte within the device, and the denuded oocyte may be released from the device when the denudation level reaches a predetermined threshold value. In some embodiments, when the measured denudation level is less than the predetermined threshold value, a closed-loop controller described elsewhere herein may be employed to subject the oocyte complexes within the fluid channel to additional rounds of repeated flow (e.g., oscillatory flow) for additional denudation. The controller may be operationally linked to one or more components described here (e.g., one or more pressure sources, inlets and / or outlets, fluid controls) to control the flow of fluid and oocyte complexes within the device. In some embodiments, upon reaching a predetermined denudation level, the controller may be operated to stop the repeated flow (e.g., oscillatory flow) through the fluidic channel. In some cases, the denuded oocytes may be released from device via one or more outlets. For example, in some embodiments in which the device comprises a first outlet downstream of the capture filter, the denuded oocytes may be caused to flow in the first direction through the plurality of sub-channels in the capture region via an application of a pressure by the first pressure source. In embodiments in which the sub-channels in the capture region are sized to allow denuded oocytes (e.g., bare oocytes without the bound non-oocyte cells) to flow readily through, the denuded oocytes may flow through the capture region and flow out of the first outlet. In some embodiments in which the sub-channels in the capture region are sized slightly smaller than the denuded oocyte, the denuded oocyte may be trapped at the capture filter. In such cases, a pressure may be applied to cause slight deformation in shape and / or size of the denuded oocyte, such that the oocyte may be forced through sub-channels in the capture region. The first outlet may be actuated to open by the controller and / or fluid controls to release the oocyte. FIG.2B can be used to illustrate one such embodiment. For example, as shown, the controller 190 may be operated to stop the repeated flow (e.g., oscillatory flow) through the fluidic channel upon detecting a measured parameter of the oocyte complex (e.g., denudation level) and trigger release of the denuded oocyte from the device. During the release, the denuded oocytes may be caused to flow in the first direction 12 through the plurality of sub- channels 177 in the capture region 172 via a pressure applied by the first pressure source 155. In some cases, the denuded oocyte may readily flow through the sub-channels 177 and flow out of the outlet 170. In some cases, a slight pressure may be applied by the first pressure source to cause the denuded oocytes to deform in shape and / or size, such that the denuded oocytes may squeeze through sub-channels 177 in the capture region 155 and flow out of the outlet 170 downstream of the capture region 172. Alternatively, or additionally, in some embodiments in which the device comprises a second outlet upstream of the capture filter, the denuded oocytes trapped at the capture region may be caused to flow in the second direction (e.g., a reverse direction) via an application of a pressure by the second pressure source. The second outlet may be actuated to open by the controller and / or fluid controls and the denuded oocyte may be caused to flow out of the second outlet, according to some embodiments. One such embodiment is illustrated in FIG.9B. For example, as shown, the denuded oocytes trapped at the capture region may be caused to flow in the second direction (e.g., a backward flow) via an application of a pressure by the second pressure source, and subsequently released via the second outlet. In some embodiments, one or more chemicals and / or enzymatic solutions may be flowed through the fluidic channel to facilitate denudation of the oocytes. In some cases, the one or more chemical and / or biological solutions may include an enzyme capable of removing one or more non-oocyte cells bounded to an oocyte. Non-limiting examples of chemicals and / or biological disassociating enzymes may include hyaluronidase, cumulase, trypsin, and / or pronase. The one or more chemical and / or enzymatic solutions may be flowed into the device via the one or more inlets before, during, and / or after the oscillatory flow steps, according to some embodiments. In some embodiments, the method comprises repeatedly causing flow of a fluid containing an oocyte complex comprising an oocyte and non-oocyte cells through a fluidic channel, such that the oocyte separates from the non-oocyte cell. In some embodiments, the fluid containing the complex flowing through the fluidic channel may be repeated for a plurality of times, such as at least 2 times, at least 5 times, at least 10 times, at least 20 times, at least 30 times, at least 50 times, and / or up to 100 times, up to 200 times, up to 500 times, up to 1000 times, or more. Combinations of the above-referenced ranges are possible (e.g., at least 2 times and up to 500 times, or at least 10 times and up to 1000 times). Other ranges are also possible. As mentioned, the flow of fluid may be repeating, or oscillatory in some embodiments. In some embodiments, the repeated flows described herein may lead to a relatively high denudation level. For example, in some embodiments, at least 50%, at least 60%, at least 70%, 80%, at least 85%, at least 90%, or more, and / or up to 95%, up to 97%, up to 99%, up to 99.5%, up to 99.9%, or 100% of the non-oocyte cells in the complex are removed during repeated flow of the complex through the fluidic channel. In some embodiments, the method comprises repeatedly flowing a fluid containing an oocyte complex comprising an oocyte and non-oocyte cells through a fluidic channel to remove non-oocyte cells until a predetermined (and desirable) amount of non-oocyte cells is left behind on (or bounded to) the oocyte. In some cases, such a method may be employed to produce an oocyte complex containing a desirable amount of non-oocyte cells for use in non-ICSI IVF applications. As noted elsewhere herein, the fluidic channel may comprise a plurality of posts defining sub-channels between neighboring pairs of posts, e.g., as shown in FIGS.2A-2E and FIG.3B. In some such embodiments, the flows may be repeated such that the complex passes the plurality of posts at least 2 times, at least 5 times, at least 10 times, at least 20 times, at least 30 times, at least 50 times, and / or up to 100 times, up to 200 times, up to 500 times, up to 1000 times, or more. Combinations of the above-referenced ranges are possible (e.g., at least 2 times and up to 500 times, or at least 10 times and up to 1000 times). In some embodiments, upon repeatedly causing a flow of fluid containing the one or more oocytes through the fluidic channel, the oocyte may repeatedly flow across an imaginary line within the fluidic channel multiple times, such as at least 2 times, at least 5 times, at least 10 times, at least 20 times, at least 30 times, at least 50 times, and / or up to 100 times, up to 200 times, up to 500 times, up to 1000 times, or more. Combinations of the above-referenced ranges are possible (e.g., at least 2 times and up to 500 times, or at least 10 times and up to 1000 times). For example, as shown in FIGS.1A and 2E, upon repeatedly flowing the fluid containing the one or more oocyte complex 18 through the fluidic channel 110 or 110a, the oocyte complex 18 may repeatedly flow across an imaginary axis 20 of the microfluidic channel. The imaginary line, according to some embodiments, is defined in a direction orthogonal to a direction of bulk fluid flow (e.g., direction 12 or 14) within the fluidic channel. The repeated flows, according to some embodiments, may be oscillatory or non- oscillatory in nature. As noted elsewhere herein, in some embodiments, the repeated flows may be oscillatory in nature, e.g., such as capable of oscillating between a first flow in a first direction and a second flow in the second direction (e.g., as shown in FIGS.1A-1B or FIGS. 2D-2E). In some embodiments, the repeated flows through the fluidic channel may be non- oscillatory in nature. For example, in some cases, at least some of the repeated flows through the channel may be in the same direction, e.g., either in a first direction or a second direction. In some embodiments, the first direction may be a clockwise direction and the second direction may be counterclockwise direction. FIGS.3A-3B can be used to illustrate one such embodiment. For example, as shown in FIG.3A, a microfluidic device 200 may comprise a fluidic channel 210 formed between two concentric walls, e.g., an outer wall and an inner wall. The fluidic channel may comprise one or more sub-channels 230 defined by extruded portions on the inner and outer wall, in some embodiments. The sub-channels 230, in some cases, may be sized to have a minimum cross- sectional dimension comparable to or slightly larger than a target entity (e.g., an oocyte) flowing through sub-channel. The sub-channels 230 may have any of a variety of properties (e.g., teeth, minimum cross-sectional dimension) described elsewhere herein. In such a fluidic channel, a fluid containing an oocyte complex 18 comprising an oocyte 18a and non-oocyte cells 18b may be caused to repeatedly flow in the same direction (e.g., clockwise or counterclockwise) through the sub-channels 230, such that the oocyte 18a separates from the non-oocyte cells 18b. In some cases, after reaching a predetermined denudation level, an outlet 250 may be actuated to open and the denuded oocyte may exit from the outlet 250. In some embodiments, to facilitate flow of the fluid around the fluidic channel, the outer and / or inner walls of the fluid channel may be actuated to rotate in a particular direction. FIG.3B can be used to illustrate another embodiment in which the fluidic channel shown in FIG.3A comprises a plurality of posts 220 therein. The plurality of posts 220 may define a plurality of sub-channels between neighboring pairs of posts. The plurality of posts and / or sub-channels may have any of a variety of properties (e.g., shapes, sizes, teeth) described elsewhere herein. The fluidic channel in FIG.3B may be employed for repeated fluid flow in the same manner as the fluidic channel in FIG.3A. For example, a fluid containing an oocyte complex comprising an oocyte and non-oocyte cells may be repeatedly flowed in the same direction (e.g., clockwise or counterclockwise) through some of the sub-channels defined by the plurality of posts 220, such that the complex is denuded and the oocyte separates from the non- oocyte cells. In some embodiments, the method comprises passing one or more oocyte complexes through a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, such that at least 50%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, and / or up to 95%, up to 99%, up to 99.5%, up to 99.9%, or up to 100% of a total amount of the bounded non-oocyte cells are removed when the complex flows through the sub-channels. In some embodiments, at least 90% of the non-oocyte cells are removed when the complex flows through the sub-channels described herein. For example, the oocyte complex may be passed through fluidic channels having any of a variety of configurations, e.g., as shown in FIGS.1-3B. In some embodiments, a method of manipulating an oocyte complex comprising an oocyte and non-oocyte cells is described herein. In some cases, the method comprises causing a flow of fluid containing the complex in a channel dimensioned to allow the oocyte to flow through only if not bound to the non-oocyte cells. For example, referring again to FIG.2A-2C, one or more of the sub-channels 130 in the denuder region 115 of the fluidic channel 110 may be sized to have a minimum cross-sectional dimension comparable to bare oocytes (e.g., oocytes not bounded to non-oocyte cells), such that only bare oocytes may readily pass therethrough. The sub-channel described herein may have any of a variety of minimum cross- sectional dimensions described elsewhere herein. In some embodiments, under an application of sufficient pressure (e.g., such as induced by a pressure source), oocytes complexes having sizes larger than the minimum cross-sectional dimension of the sub-channel may be temporarily deformed and forced through some of the sub-channels, e.g., as shown in FIGS.2A-2C. For example, as shown in FIG.2B, pressure source 155 may be employed to exert a sufficient pressure to cause a flow in the first direction 12 at a sufficient flow rate, such that oocyte complexes having sizes larger than the minimum cross-sectional dimensions of some of the sub-channels 130 may be temporarily deformed and forced through the sub-channels 130. In some cases, causing oocyte complexes to flow through sub-channels dimensioned to have sizes comparable to bare oocytes may facilitate denudation of the oocyte from bounded non-oocyte cells. In some embodiments, the fluid containing the complex may be caused to flow repeatedly (via either the oscillatory or non-oscillatory flow described elsewhere herein) through the sub-channel(s) dimensioned to have minimum cross-sectional dimensions comparable to bare oocyte, e.g., for at least 2 times, at least 5 times, at least 10 times, at least 20 times, at least 30 times, at least 50 times, and / or up to 100 times, up to 200 times, up to 500 times, up to 1000 times, or more. Combinations of the above-referenced ranges are possible (e.g., at least 2 times and up to 500 times, or at least 10 times and up to 1000 times). Other ranges are also possible. Such repeated flow may lead to repeated denudation of the complex, which can lead to in an enhanced denudation level. In addition to the above, the use of oscillatory flow in a fluidic channel may facilitate effective cleaning of non-target entities (e.g., debris and / or contaminates) contained within the fluid samples from the channels to prevent clogging of the channels. For example, according to some embodiments, larger debris contained with the fluid may be trapped by some of the plurality of sub-channels in the denuder region, e.g., denuder region 115 in FIG.2A. The trapped debris, according to some embodiments, may be subjected to oscillatory flows within the device when the fluid is caused to flow in a first direction, e.g., as shown in FIG.2B, followed by a flow in a second direction, e.g., as shown in FIG.2C. The use of repeated oscillatory flow may mechanically break up larger debris originally trapped in the sub-channels into small pieces, thus causing the small pieces of debris to flow through the sub-channels and subsequently be removed from the channel. In some embodiments, a method of preparing follicular fluid to isolate and denude an oocyte complex comprising an oocyte and non-oocyte cells for egg banking, egg freezing, and / or in-vitro fertilization is disclosed here. The method may comprise, according to some embodiments, passing the follicular fluid through a fluidic channel comprising a plurality of posts such that the complex flows through sub-channels defined between neighboring pairs of posts. The fluid channel, the plurality of posts, and / or the sub-channels may have any of a variety of properties (e.g., dimensions, shapes, configurations, arrangements, amounts, etc.) as described elsewhere herein and / or with respect to FIGS.2A-3B. FIGS.2A-3B may be used to illustrate one such embodiment. For example, as shown in FIGS.2A-2E, a follicular fluid may be passed through a fluidic channel (e.g., channel 110 or 210) comprising a plurality of posts (e.g., posts 120 or 220) such that the complex flows through sub-channels (e.g., sub-channels 130 or 230) defined between neighboring pairs of posts. According to some embodiments, the complex may be repetitively passed through the fluidic channel via an oscillatory motion, e.g., as illustrated in FIGS.2A-3B. For example, the complex may be passed through the fluidic channel in a first direction through some of the sub- channels from an inlet to an outlet of the fluidic channel, e.g., as illustrated by FIGS.2B or 2D, followed by a flow through the fluidic channel in a second direction through some of the sub- channels from the outlet to the inlet of the fluidic channel, e.g., as illustrated by FIGS.2C or 2E. In some embodiments, the complex may be repetitively passed through the fluidic channel in a non-oscillatory motion, e.g., as shown in FIGS.3A-3B. Upon flowing the complex through the sub-channels, at least a portion (e.g., at least 10%, at least 25%, at least 50%, at least 90%, and / or up to 95%, up to 99%, or up to 100%) of the non-oocyte cells may be removed from the oocyte complex. While the above-referenced embodiments are generally directed to methods of denuding oocyte complex comprising an oocyte and non-oocyte cells to separate the oocyte from the non- oocyte cells, it should be understood that the disclosure is not so limited, and that in other embodiments, the methods may be generalized to denuding any target entity-secondary entity complex other than the oocyte complex. For example, any of the above-reference methods and / or devices may be employed to denude target entity-secondary entity complex comprising a target entity and one or more secondary entities to separate the target entity from the secondary entities. The target entity may include any of a variety of cell types, including, but not limited to tumor cells. For example, certain embodiments comprises passing the target entity-secondary entity complex through a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, such that at least 50% (e.g., at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 99%, at least 99.9%, up to 100%) of the secondary entities are removed when the complex flows through sub-channels. The target entity- secondary entity complex may be passed repeatedly through a device having any of a variety of configurations noted herein, such as the devices illustrated in FIGS.2A-3B, via either an oscillatory flow (FIGS.2A-2C) or a non-oscillatory flow (FIGS.3A-3B). In some embodiments, the method comprises causing a flow of fluid containing the target entity-secondary entity complex in a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, such that the complex passes the plurality of posts at least 2 times (e.g., at least 5 times, at least 10 times, at least 20 times, at least 30 times, at least at least 20 times, at least 30 times, at least 50 times, and / or up to 100 times, up to 200 times, up to 500 times, up to 1000 times). In some embodiments, the fluid containing the target entity-secondary entity complex may be caused to flow in an oscillatory fashion, e.g., as shown in FIGS.2A-2E. For example, a first flow of a fluid containing the complex may be caused in a first direction 12 through a fluidic channel, followed by a second flow of the fluid containing the complex in a second direction 14 through the fluidic channel. In some cases, at least some (e.g., at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, or more) of the one or more secondary entities from the complex is removed as the complex flows through the fluidic channel 110 in the first direction 12 and at least some (e.g., at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, or more) of the one or more secondary entities from the complex as the complex flows through the fluidic channel 110 in the second direction 14. In some embodiments, the fluid containing the target entity-secondary entity complex may be caused to flow repeatedly in a non-oscillatory fashion, as shown in FIGS.3A-3B. In some cases, the fluid containing the target entity-secondary entity complex (e.g., complex 18) may be caused to flow in the fluidic channel such that the complex flows across an imaginary line (e.g., imaginary line 20 as shown in FIG.2D) within the fluidic channel at least 2 times (e.g., at least 5 times, at least 10 times, at least 20 times, at least 30 times, at least at least 20 times, at least 30 times, at least 50 times, and / or up to 100 times, up to 200 times, up to 500 times, up to 1000 times). In some embodiments, a method of manipulating a target entity-secondary entity complex comprising a target entity and one or more secondary entities is described herein. In some cases, the method comprises causing a flow of fluid containing the complex in a channel dimensioned to allow the target entity to flow through only if not bound to the secondary entities. For example, referring again to FIG.2A-2C, one or more of the sub-channels 130 in the denuder region 115 of the fluidic channel 110 may be sized to have a minimum cross- sectional dimension comparable to a bare target entity (e.g., target entity not bounded to secondary entities), such that only denuded target entity may readily pass therethrough. The sub-channel described herein may have any of a variety of minimum cross-sectional dimensions described elsewhere herein. In some embodiments, under an application of pressure, the fluid containing the complex may be caused to flow repeatedly (via either the oscillatory or non-oscillatory flow described elsewhere herein) through the sub-channel(s), e.g., for at least 2 times, at least 5 times, at least 10 times, at least 20 times, at least 30 times, at least 50 times, and / or up to 100 times, up to 200 times, up to 500 times, up to 1000 times, or more. Combinations of the above- referenced ranges are possible (e.g., at least 2 times and up to 500 times, or at least 10 times and up to 1000 times). Other ranges are also possible. Such repeated flow may lead to repeated denudation of the complex, which can lead to in an enhanced denudation level of the complex. In some embodiments, the above-referenced methods or devices may be employed to dissociate conglomerates or aggregates of target cells into individual cells for use in application such as in cell sorting, single-cell sequencing, etc. For example, in some embodiments, the devices and / or methods described herein may be used to process a fluid containing tumor tissue or circulating tumor cell clusters (CTCCs). The fluid may be passed into the denuder region, where, under an application of repeated flow (e.g., oscillatory flow) and / or enzyme treatment, cell-cell interactions may be weakened and the tissue or the CTCC cluster may dissociate into individual cells in the denuder region. The individual cells may be in turn captured by the capture region and released from the device for further use, according to some embodiments. In addition, in accordance with certain embodiments, it has been found that more efficient enrichment of oocytes can be achieved, compared to manual techniques. In some cases, a variety of oocytes have been determined, e.g., in various stages of maturation (e.g., in the GV stage (Germinal Vesicle), and / or the M1 (Metaphase I) and M2 (Metaphase II) stages). In contrast, manual techniques are usually unable to find and isolate immature oocytes. In some embodiments, one or more devices described herein may be defined using any suitable form factor. In some embodiments, the one or more devices is defined by a rectangular form factor, for example, as shown in FIG.2. In other embodiments, however, the one or more devices is defined by a circular form factor, for example, as shown in FIG.13. In some embodiments, the circular form factor comprise one or more holes. In some embodiments, the one or more holes are concentric about the center of the device. Other form factors are also possible in other embodiments. In some embodiments, the one or more devices described herein comprise a wall angle of between 2 degrees and 10 degrees, relative to an axis that is perpendicular to a bottom surface of the microfluidic device. In some embodiments, the wall angle is greater than or equal to 1 degree, greater than or equal to 2 degrees, greater than or equal to 3 degrees, greater than or equal to 4 degrees, greater than or equal to 5 degrees, greater than or equal to 6 degrees, greater than or equal to 7 degrees, greater than or equal to 8 degrees, greater than or equal to 9 degrees, or greater than or equal to 10 degrees, relative to an axis that is perpendicular to a bottom surface of the microfluidic device. In some embodiments, the wall angle is less than or equal to 10 degrees, less than or equal to 9 degrees, less than or equal to 8 degrees, less than or equal to 7 degrees, less than or equal to 6 degrees, less than or equal to 5 degrees, less than or equal to 4 degrees, less than or equal to 3 degrees, less than or equal to 2 degrees, or less than or equal to 1 degree, relative to an axis that is perpendicular to a bottom surface of the microfluidic device. Combinations of the above recited ranges are also possible in some embodiments. For example, in some embodiments, the wall angle is greater than or equal to 1 degree and less than or equal to 10 degrees, relative to an axis that is perpendicular to a bottom surface of the microfluidic device. In some embodiments, the wall angle is 3 degrees relative to an axis that is perpendicular to a bottom surface of the microfluidic device. In other embodiments, the wall angle is 5 degrees relative to an axis that is perpendicular to a bottom surface of the microfluidic device. In some embodiments, a device may comprise one or more regions (e.g., filter regions, denuder regions, inertial focusing regions, concentrator regions, and / or capture regions, etc.) with one or more wall angles, according to some embodiments. In some embodiments, the one or more wall angles of the one or more regions is the same. In other embodiments, the one or more wall angles of the one or more regions is different. In some embodiments, the one or more wall angles of the one or more regions may be selected from any one of the above recited ranges and / or combinations thereof. As a non-limiting example, in some cases, a filter region has a 3 degree wall angle and a denuder region has a 5 degree wall angle. In another non- limiting example, the filter region and denuder region both have a 3 degree wall angle or a 3 degree wall angle. The skilled artisan will understand that devices comprising adjacent sidewalls having non-zero wall angles may define a channel with a trapezoidal-like shape, wherein a first portion of the trapezoidal-like channel will have a larger cross-sectional dimension than the second portion of the trapezoidal-like channel. Other shapes are also possible in some embodiments, e.g., parallelogram-like shapes. Similarly, devices comprising a plurality of posts (e.g., filter region, denuder region, and capture region) having non-zero wall angles may in some embodiments define a plurality of trapezoidal-like sub-channels between neighboring pairs of posts (see, as examples, FIG.14A and 14B). In some embodiments, a cross-sectional dimension of a first portion of a trapezoidal-like sub-channel is larger than the cross-sectional dimension of a second portion of the trapezoidal-like sub-channel. In some embodiments, the cross-sectional dimension of the first portion of the trapezoidal-like sub-channel is smaller than the cross-sectional dimension of the second portion of the trapezoidal-like sub-channel. FIG.14A illustrates exemplary wall dimensions for a 3-degree wall angle and FIG. 2141B illustrates exemplary wall dimensions for a 5-degree wall angle, as non-limiting examples. However, wall angles may vary in other embodiments, e.g., from about 1 degree to about 10 degrees, etc. FIG.14C shows a scanning electron micrograph of a denudation region with a 3 degree wall angle. In some embodiments, a plurality of trapezoidal-like sub-channels (e.g., formed by neighboring pairs of posts having a non-zero wall angle) has an average cross-sectional dimension of between 10 microns and 200 microns. In some embodiments, the average cross- sectional dimension of the plurality of trapezoidal-like sub-channels (e.g., formed by neighboring pairs of posts having a non-zero wall angle) 10 microns and 200 microns. In some embodiments, the average cross-sectional dimension of the plurality of trapezoidal-like sub- channels (e.g., formed by neighboring pairs of posts having a non-zero wall angle) is greater than or equal to 10 microns, greater than or equal to 25 microns, greater than or equal to 50 microns, greater than or equal to 75 microns, greater than or equal to 100 microns, greater than or equal to 125 microns, greater than or equal to 150 microns, greater than or equal to 175 microns, or greater than or equal to 200 microns,. In some embodiments, the average cross- sectional dimension of the trapezoidal-like sub-channels (e.g., formed by neighboring pairs of posts having a non-zero wall angle) is less than or equal to 200 microns, less than or equal to 175 microns, less than or equal to 150 microns, less than or equal to 125 microns, less than or equal to 100 microns, less than or equal to 75 microns, less than or equal to 50 microns, less than or equal to 25 microns, or less than or equal to 10 microns. Combinations of the above recited ranges are also possible in some embodiments. For example, in some embodiments, the average cross-sectional dimension of the trapezoidal-like sub-channels is greater than or equal to 10 micron and less than or equal to 200 microns. In some embodiments, a plurality of trapezoidal-like sub-channels in a filter region, a denuder region, and / or a capture region (e.g., formed by neighboring pairs of posts having a non-zero wall angle) has an average cross-sectional dimension of between 10 microns and 200 microns. In some embodiments, the average cross-sectional dimension of the plurality of trapezoidal-like sub-channels in the filter region, a denuder region, and / or a capture region (e.g., formed by neighboring pairs of posts having a non-zero wall angle) is greater than or equal to 10 microns, greater than or equal to 25 microns, greater than or equal to 50 microns, greater than or equal to 75 microns, greater than or equal to 100 microns, greater than or equal to 125 microns, greater than or equal to 150 microns, greater than or equal to 175 microns, or greater than or equal to 200 microns,. In some embodiments, the average cross-sectional dimension of the trapezoidal-like sub-channels in the filter region, a denuder region, and / or a capture region (e.g., formed by neighboring pairs of posts having a non-zero wall angle) is less than or equal to 200 microns, less than or equal to 175 microns, less than or equal to 150 microns, less than or equal to 125 microns, less than or equal to 100 microns, less than or equal to 75 microns, less than or equal to 50 microns, less than or equal to 25 microns, or less than or equal to 10 microns. Combinations of the above recited ranges are also possible in some embodiments. For example, in some embodiments, the average cross-sectional dimension of the trapezoidal-like sub-channels in the filter region, denuder region, and / or a capture region is greater than or equal to 10 microns and less than or equal to 200 microns. In some embodiments, an average cross-sectional dimension of a plurality of sub- channels in a denuder region is between 10 microns and 200 microns and the average cross- sectional dimension of the sub-channels in a capture region is between 10 microns and 200 microns. In some embodiments, a plurality of trapezoidal-like sub-channels (e.g., formed by neighboring pairs of posts having a non-zero wall angle) has an average height of between 100 microns and 400 microns. In some embodiments, the average height of the plurality of trapezoidal-like sub-channels (e.g., formed by neighboring pairs of posts having a non-zero wall angle) is greater than or equal to 100 microns, greater than or equal to 130 microns, greater than or equal to 160 microns, greater than or equal to 190 microns, greater than or equal to 220 microns, greater than or equal to 250 microns, greater than or equal to 280 microns, greater than or equal to 310 microns, greater than or equal to 340 microns, greater than or equal to 370 microns, or greater than or equal to 400 microns. In some embodiments, the average height of the plurality of trapezoidal-like sub-channels (e.g., formed by neighboring pairs of posts having a non-zero wall angle) is less than or equal to 400 microns, less than or equal to 370 microns, less than or equal to 340 microns, less than or equal to 310 microns, less than or equal to 280 microns, less than or equal to 250 microns, less than or equal to 220 microns, less than or equal to 190 microns, less than or equal to 160 microns, less than or equal to 130 microns, or less than or equal to 100 microns. Combinations of the above recited ranges are also possible in some embodiments. For example, in some embodiments, the average cross-sectional dimension of the trapezoidal-like sub-channel is greater than or equal to 100 micron and less than or equal to 400 microns. In some embodiments, a plurality of trapezoidal-like sub-channels in a filter region, a denuder region, and / or a capture region (e.g., formed by neighboring pairs of posts having a non-zero wall angle) has an average height of between 100 microns and 400 microns. In some embodiments, the average height of the plurality of trapezoidal-like sub-channels in the filter region, denuder region, and / or capture region is greater than or equal to 100 microns, greater than or equal to 130 microns, greater than or equal to 160 microns, greater than or equal to 190 microns, greater than or equal to 220 microns, greater than or equal to 250 microns, greater than or equal to 280 microns, greater than or equal to 310 microns, greater than or equal to 340 microns, greater than or equal to 370 microns, or greater than or equal to 400 microns. In some embodiments, the average height of the plurality of trapezoidal-like sub-channels in the filter region, denuder region, and / or capture region is less than or equal to 400 microns, less than or equal to 370 microns, less than or equal to 340 microns, less than or equal to 310 microns, less than or equal to 280 microns, less than or equal to 250 microns, less than or equal to 220 microns, less than or equal to 190 microns, less than or equal to 160 microns, less than or equal to 130 microns, or less than or equal to 100 microns. Combinations of the above recited ranges are also possible in some embodiments. For example, in some embodiments, the average cross- sectional dimension of the plurality of trapezoidal-like sub-channels in the filter region, denuder region, and / or capture region is greater than or equal to 100 micron and less than or equal to 400 microns. In some embodiments, an average height of a plurality of sub-channels in a denuder region is between 100 microns and 400 microns and the average height of the sub-channels in a capture region is between 100 microns and 400 microns. Without wishing to be bound by any particular theory, it is generally believed that devices comprising non-zero wall angles in the denuder region may permit sequential shear induced break up of oocyte complexes, that may be advantageous for denuding oocytes in certain cases. As described above, and elsewhere herein, posts within the denuder region may in some cases comprise teeth that serve as strippers to denude the oocytes (see FIGS.1-3). In devices comprising non-zero wall angles, these strippers become tapered, as illustrated in FIG. 14C. Neighboring posts may be used in some instances to create trapezoidal-like sub-channels with a series of tapered strippers. (FIG.14C). Without wishing to be bound by any theory, it is generally believed that initially large oocyte complexes can be denuded at the widest part of the tapered strippers to yield partially denuded oocytes, which may further be denuded via repeated passage through a more narrow portion of the tapered strippers (e.g., via oscillatory flow). U.S. Provisional Patent Application Serial No.63 / 518,322, filed August 8, 2023, entitled “Microfluidic Methods and Apparatuses for Denudation of Oocytes Utilizing Oscillatory Flow,” and U.S. Provisional Patent Application Serial No.63 / 518,323, filed August 8, 2023, entitled “Devices and Methods for Isolation of Biological Entities in Suspension” are each incorporated herein by reference in its entirety. The following examples are intended to illustrate certain embodiments of the present disclosure, but do not exemplify the full scope of the disclosure. EXAMPLE 1 This example features microfluidic systems and methods utilizing oscillatory flow fields for the denudation of mammalian (e.g. human, mouse, bovine) cumulus / granulosa oocyte complexes (COCs) containing oocytes. An example of one such device is shown in FIG.4A. As shown, the microfluidic system contains an array of denudation constrictions in a microfluidic channel, where the widths of the constrictions are similar to the hydrodynamic size of the target oocyte and the cumulus cell layer around them, and the surface of the constriction walls have extruded features (i.e., teeth) that can be of various geometries (e.g. triangles, rectangles, saw-teeth). In a typical application, a fluid sample which contains oocytes (along with other cell and tissue debris) may be processed, such as follicular fluid collected from a patient during IVF treatment, COCs purified and suspended in media, inseminated COCs generated during standard IVF process, and / or dissociated human, bovine or mouse ovaries. The sample fluid containing oocytes may be introduced to the microfluidic device through an inlet port and passed through the array of denudation constrictions via a steady or oscillatory flow field. Then, the oscillatory flow field may be applied such that the direction of flow may be reversed in a controlled periodic fashion, thereby allowing the oocytes to interact with the constriction array a multitude of times and get denuded over time. Examples of parameters that characterize the oscillatory flow may include the frequency of oscillation (f), duty cycle (percent duration of flow in one flow direction) of oscillation (D), and flow-rate (q) in each flow direction. Finally, the denuded oocytes may be released from the chip via a steady or oscillatory flow field. A typical fluidic constriction channel and post is shown in FIG.5 and FIG.6. The narrowest section of the constriction may be defined as the constriction width (w), which may be used to characterize the shortest distance between the extruded features of the constriction. Extruded features can be saw-teeth shaped, rectangular or other quadrilaterals, triangular, or different polygonal or fully- or partially-circular geometries (FIGS.7A-7D). In one example, the extruded features may be similar to saw-teeth shaped and may have the following geometrical parameters: LFEAT-1= 15 µm, LFEAT-2= 52 µm, LFEAT-3= 15 µm, LFEAT-4= 30 µm, αFEAT-1= 30°, αFEAT-2= 60°. In another example, the extruded featured may be triangular shaped and may have the following geometrical parameters: LFEAT-3= 0. In yet another example, the extruded features may be rectangular shaped and may have the following parameters: LFEAT-2= LFEAT-4, and αFEAT-1= αFEAT-2. In yet another example, the extruded featured may be circular shaped and the features may be defined by the circle radius (RFEAT), the offset of its center from the wall (LOFFSET), and the distance between features (LFEAT). In some cases, the length of the feature sides (LFEAT-1,2,3,4) can be as small as 1 µm and as large as 1000 µm. In some embodiments, the angles (αFEAT-1,2) can be as small as 0.1° and as large as 179.9°. In some cases, the extruded feature may be circular,where the feature diameter can beas small as 1 µm and as large as 1000 µm. Posts can have one repeating pattern of a geometrical feature, or a combination of different geometrical features. Depending on the extrusion geometry, the extruded features can be symmetrical with respect to the flow direction, or counter- angled towards one flow direction (Uni-directional, FIG.5) or both of the flow directions (Bi-directional, FIG.6) to improve oocyte denudation performance. In one example, the extruded features are similar to the shape of saw-teeth and are angled towards both flow directions (FIG.6). In some cases, no extrusion features may be used, and the constriction width (w) would be the distance between straight channel walls. In some such cases, the denudation can be achieved by repeated encounter of oocytes with channel segments narrower or in the same order of width to the COCs. A constriction array can be defined based on the number of fluidic constrictions per row (m) and the number of constriction rows (n), and the total number of fluidic constrictions N. FIG.8 shows an example of a constriction array with m = 6 or 7 per row, n = 6 rows, and N = 39. In an example, the width of the fluidic constrictions is the same within a constriction row, but can change between different rows. For example, FIG.8 shows a constriction array where rows 1 and 2 have a constriction width of 160 µm, rows 3 and 4 have a constriction width of 140 µm, and rows 5 and 6 have a constriction width of 120 µm. Depending on the size of the targeted mammalian oocytes, the smallest constriction width (w) can be as small as 50 µm. Depending on the cumulus mass around the targeted oocytes, the largest constriction width (w) can be as large as 1000 µm. In some cases where the footprint of the device is to be minimized, both the number of fluidic constrictions per row (m) and the number of constriction rows (n) can be as small as 1. In some embodiments, m and n can be as large as 1000. In some embodiments, multiple constriction arrays can be utilized in a microfluidic chip, where they are connected to each other in series, in parallel, or used in conjunction with microfluidic sections of the microfluidic chip with other functionalities. In some cases, a final row of filter posts with a smaller gap size and / or reduced flow rate can be added to prevent oocytes from escaping the chip. In some cases, the height (Hd) of the device can be defined as the height (depth) of thefeatures in the z-direction (normal tothe plane of the Figures). In one example, the height ofthe device may be about 350 µm. In some cases, the height of the device is the same throughout the sections of the chip. In some cases, the height of the device is different in different sections of the chip. In some cases, the height of the device in a given section can be as small as 50 µm, and as large as 10,000 µm. The flowrates during the forward (direction 1) phase of the oscillatory flow and thebackward (direction 2)phase of the oscillatory flow can be defined as QFWand QBW. Theflowrates QFWand QBWcan be the same,or different. The net flowrate in the device can beadjusted towards either direction by a combination offlowrates (QFWand QBW) and the dutycycle (percent time of the flow in one direction during one full periodof the oscillatory flow).In a typical embodiment, the duty cycle may be about 70% (meaning flow is going in the forward direction 70% of the period, i.e.70 seconds in forward direction, then 30 seconds in reverse direction). In some cases, the duty cycle can be between 0.1% to 99.9%. In one example, the forward and backward flowrate is about 2 mL / min in each direction. In another example, the flowrate in each direction can be as low as 0.01 mL / min and as high as 1000 mL / min. Oscillatory flow field in a microfluidic chip can be generated by numerous combinations of flow source units (e.g. pressure sources, syringe pumps), sample reservoirs (e.g. syringes, conical tubes), and / or flow control units (e.g. valves). In one embodiment where only one control signal is used for creating an oscillatory flow field, flow may be modulated using two different pressure sources, where the pressures are setat P1for inlet 1 and P2forinlet 2, where P2is greater than P1(FIG.9A). P1may be connected directly to the inlet 1 via tubing, whereas P2may be connected to the inlet 2 via tubing which goes through a solenoid activated pinch valve, and the valve may be controlled by a preprogrammed microprocessor (e.g. Arduino). In some cases, when the pinch valve is in a closed position, no flow can pass through the valve and the flow direction may be from inlet 1 towards the outlet. When the pinch valve is in an open position, flow can pass through and the flow direction may be from inlet 2 towards the inlet 1, which may in turn generate the reverse flow through the constriction array. Meanwhile, there may also be flow from inlet 2 towards the outlet (which would not contribute to the oscillatory flow field). As shown in FIG.9A, the oocyte capture row may stop the oocytes from moving farther during forward flow. This may be achieved by expanding the channel to slow down the flow, and the capture row gaps may have a width slightly smaller than the oocyte. In this example, after a pre-set amount of application of the oscillatory flow field, the valve connected to inlet 2 may be permanently closed, and inlet pressure P1 may be increased to push the oocytes through the capture row and release them through the outlet. Another example of the microfluidic device is illustrated in FIG.9B. As shown, in this example of the device, an oocyte release outlet may be introduced before the capture row along with the second pinch valve. In this case, the second pinch valve may stay closed during oscillatory denudation. After a pre-set amount of application of the oscillatory flow field, the first pinch valve may be permanently opened, inlet 1 may be closed, and the second pinch valve may be opened to release the oocytes with a backward flow to the oocyte release outlet. The advantage of this design is that the oocytes do not pass through the oocyte capture row to be released. Another example of the microfluidic device is illustrated in FIG.9C. As shown, an oocyte capture row may not be present in the device. In this case, the flow parameters may be adjusted to ensure that oocytes stay on the chip during the application of the oscillatory flow field, such that the oocytes do not flow through the outlet channel and leave the chip. In this case, after a pre-set amount of application of the oscillatory flow field, the valve connected to inlet 2 may be permanently closed, and oocytes may be released through the outlet port. In some cases, samples can be treated with hyaluronidase or other similar solutions that facilitate oocyte denudation before the oocytes are transferred to the device. For example, hyaluronidase or other similar solutions that facilitate oocyte denudation can be introduced to the device while the oocytes are in the device. This could be accomplished by through one of the existing inlets, or another embodiment of the system with a different inlet for hyaluronidase or similar solution. Denudation may be carried out using a microfluidic device described above. For example, using a device containing a plurality of saw-shaped teeth in the constriction area (as shown in FIG.5). In this device, oocyte denudation occurred gradually over processing duration, during which oocytes repeatedly travel through denudation segments (FIGS.10A- 10C). As shown, the oocyte at time tend became more denuded compared to the oocyte at time tstart. Denudation time may be defined as the total time oocytes have spent travelling through the denudation segments until all the oocytes are fully denuded. In addition to biological factors such as oocyte origin and cumulus mass, denudation time may depend on the device geometry, such as: number of fluidic constrictions per row (m), the number of constriction rows (n), and the total number of fluidic constrictions (N), and the flow parameters such as: frequency of oscillation (f), duty cycle (percent duration of flow in one flow direction) of oscillation (D), and / or pressure (P) / flow- rate (q) in each flow direction, according to some embodiments. FIG.11 shows that for one particular embodiment of the system, fully denuded bovine oocytes were obtained with oscillation frequencies ranging from 4 oscillations / min to 60 oscillations / min, at pressures from 0.5 psi to 1.0 psi which corresponds to a mean flowvelocity perdenudation constriction (i.e. per one of the fluidic constrictions as shown in FIGS.5-6) of uconstriction=12 to 24 cm / s. In some cases, oscillation frequency can be as low as 0.1 oscillations / min and as high as 10,000 oscillations / min. In different embodiments, the meanflow velocity per denudationconstriction can be as low as uconstriction= 0.01 cm / s touconstriction= 10,000 cm / s.In some cases, a closed-loop control system may be implemented to determine the flow parameters and / or time to stop the oscillatory flow and release the oocytes, based on their denudation level (FIG.12). In this case, an imaging system (e.g. camera) may be employed to take photographs periodically (or a video) to determine the level of denudation of the oocytes at a given time using an image processing algorithm. Once the satisfactory level of denudation is achieved, the microprocessor (e.g. Arduino) can close the pinch valve to release the oocytes. The microprocessor can be pre-programmed to change the flow parameters (e.g. increase the flowrate within the channel), or introduce denudation catalyzing agents (e.g. hyaluronidase) to the flow in order to facilitate denudation, if the image processing algorithm demonstrates that the desired denudation level has not achieved after a preset amount of time. In some cases, the microprocessor (e.g. Arduino, FPGA, Raspberry-Pi) can be used in conjunction with pressure control systems such as (e.g. Elveflow, Fluigent) for flow modulation, and also computer software (e.g. Python packages for computer vision) for image processing. The device and method described above may be used to denude oocyte from various liquid samples. In one application of this system, the oocyte containing fluid may be follicular fluid collected from a patient during IVF treatment. The device, by itself or by integrating with an upstream or downstream process, may be used to obtain denuded oocytes from patient’s follicular fluid. The denuded oocytes can then be either fertilized via intracellular sperm injection (ICSI), or frozen (vitrified) for later use. In another application of this system, the oocyte containing fluid may be IVF-inseminated oocytes which still retain their cumulus / granulosa cells after insemination. This system, by itself or by integrating with an upstream or downstream process, is used to obtain denuded inseminated oocytes (potential embryos) from the sample. Using an embodiment with camera imaging and closed-loop control, the system can also check for fertilization and identify and sort oocytes based on successful fertilization. In yet another application of this system, the oocyte containing fluid may be dissociated animal (mouse, bovine, or other) ovaries. The device described herein, by itself or by integrating with an upstream or downstream process, may be used to obtain denuded oocytes from this sample. The device and method described in this example may allow for denudation of oocytes in microfluidic channels of limited length and footprint, rather than using a long channel of serially or parallelly connected denudation segments. The device and method described above further allows for denudation of oocytes when the oocytes are mixed with other tissue and debris in a complex fluid (such as follicular fluid, ovarian tissue, inseminated cumulus oocyte complexes), without chip-clogging issues. Oscillatory flow through parallel channels actively can be used to clean up debris from channels, and increase the likelihood of oocytes finding and interacting with debris free denudation features during the process. Furthermore, during use, the device may allow for generation of flow fields during oscillation to change the 3D orientation of oocytes before they go through a denudation segment each time, thereby allowing for different surfaces of the oocytes to interact with denudation features and thus increase the efficiency and quality of denudation process. Improved efficiency in turn may allow for shorter duration of the denudation process and fewer interactions with denudation features (e.g., extruded portions). This may in turn reduce potentially harmful stress imposed on the oocytes during denudation process. The device and / or method described in this example further allows for precise control over the exact number of interactions between the oocytes and the denudation features, independently from the number of denudation elements on the chip. This may also allow for slower flowrates and reduced shear stress on the oocytes, in exchange for longer oscillation times. As mentioned above, the device may also allow for visual (qualitative or quantitative) temporal analysis of the denudation process, since: (i) denudation of the oocytes can occur at a small, localized section of the device; (ii) oocytes can appear repeatedly at a region of interest for viewing with the use of oscillatory flow; and (iii) flow can be stopped and restarted at will to allow for better imaging. Furthermore, the continuous visual feedback system associated with the device can allow for closed-loop control, where oocytes can be automatically (via image processing) or manually (by user) verified to be denuded before release. While several embodiments of the present disclosure have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present disclosure. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present disclosure is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the disclosure described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the disclosure may be practiced otherwise than as specifically described and claimed. The present disclosure is directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is included within the scope of the present disclosure. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control. If two or more documents incorporated by reference include conflicting and / or inconsistent disclosure with respect to each other, then the document having the later effective date shall control. All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms. The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc. As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc. When the word “about” is used herein in reference to a number, it should be understood that still another embodiment of the disclosure includes that number not modified by the presence of the word “about.” It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited. In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

What is claimed is: CLAIMS 1. A method of preparing a fluid to isolate and denude an oocyte complex comprising an oocyte and bounded non-oocyte cells for egg banking, egg freezing, and / or in-vitro fertilization, the method comprising: passing the fluid through a fluidic channel comprising a plurality of posts such that the complex flows through sub-channels defined between neighboring pairs of posts.

2. The method of claim 1, wherein the fluid comprises follicular fluid.

3. The method of any one of claims 1 or 2, wherein the fluid comprises culture fluid.

4. The method of any one of claims 1-3, wherein the complex is flowed through at least one sub-channel having a minimum cross-sectional dimension of between about 80 micrometers and about 350 micrometers.

5. The method of any one of claims 1-4, wherein the sub-channels defining a denuder region having a length within the fluidic channel of no more than 100 millimeters.

6. The method of any one of claims 1-5, wherein at least 10% of non-oocyte cells are removed when the complex flows through sub-channels.

7. The method of any one of claims 1-6, wherein at least 50% of non-oocyte cells are removed when the complex flows through sub-channels.

8. The method of any one of claims 1-7, wherein at least 90% of non-oocyte cells are removed when the complex flows through sub-channels.

9. The method of any one of claims 1-8, wherein the complex is flowed through the fluidic channel in a first direction through some of the sub-channels from an inlet to one or more outlet of the fluidic channel.

10. The method of any one of claims 1-9, wherein the complex is flowed through the fluidic channel in a second direction through some of the sub-channels from the one or more outlet to the inlet of the fluidic channel.

11. A method of denuding an oocyte complex comprising an oocyte and bounded non- oocyte cells to separate the oocyte from the non-oocyte cells, the method comprising: passing the complex through a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, at least one of the sub- channels having a minimum cross-sectional dimension of between about 50 micrometers and 350 micrometers, the sub-channels defining a denuder region having a length within the fluidic channel of no more than 100 millimeters, such that at least 10% of the non-oocyte cells are removed when the complex flows through sub- channels.

12. The method of claim 11, wherein the complex is passed through the fluidic channel in a first direction through some of the sub-channels from an inlet to one or more outlet of the fluidic channel.

13. The method of any one of claims 11-12, wherein the complex is passed through the fluidic channel in a second direction through some of the sub-channels from one or more outlet to an inlet of the fluidic channel.

14. The method of any one of claims 11-13, wherein at least 50% of the non-oocyte cells are removed when the complex flows through sub-channels.

15. The method of any one of claims 11-14, wherein at least 90% of the non-oocyte cells are removed when the complex flows through sub-channels.

16. The method of any one of claims 11-15, wherein at least one of the sub-channels having a minimum cross-sectional dimension of between 80 micrometers and 180 micrometers, 17. A method of manipulating an oocyte complex comprising an oocyte and bounded non-oocyte cells, the method comprising:causing a flow of fluid containing the complex in a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, such that the complex passes the plurality of posts at least 2 times.

18. The method of claim 17, wherein the complex passes the plurality of posts at least 5 times.

19. The method of any one of claims 17 or 18, wherein the complex passes the plurality of posts at least 10 times.

20. The method of any one of claims 17-19, wherein the complex passes the plurality of posts at least 50 times.

21. The method of any one of claims 17-20, wherein the complex passes the plurality of posts at least 100 times.

22. A method of denuding an oocyte complex comprising an oocyte and non-oocyte cells to separate the oocyte from the non-oocyte cells, the method comprising: causing a first flow of a fluid containing the complex in a first direction through a fluidic channel; removing at least some of the non-oocyte cells from the complex as the complex flows through the fluidic channel in the first direction; causing a second flow of the fluid containing the complex in a second direction through the fluidic channel; and removing at least some of the non-oocyte cells from the complex as the complex flows through the fluidic channel in the second direction.

23. The method of claim 22, wherein the fluidic channel comprises a plurality of posts defining sub-channels between neighboring pairs of posts.

24. The method of any one of claims 22-23, wherein causing a first flow comprises causing a first flow through some of the sub-channels in a first direction.

25. The method of any one of claims 22-24, wherein causing a second flow comprises causing a second flow through some of the sub-channels in a second direction. 26 The method of any one of claims 22-25, wherein causing a first flow in a first direction comprises causing a first flow from an inlet of the fluidic channel to one or more outlet of the fluidic channel.

27. The method of any one of claims 22-26, wherein causing a second flow in a second direction comprises causing a second flow from one or more outlet of the fluidic channel to an inlet of the fluidic channel.

28. The method of any one of claims 22-27, wherein the second direction is substantially opposite the first direction.

29. The method of any one of claims 22-28, wherein a pressure is applied in the first direction during the first flow by a first pressure source.

30. The method of any one of claims 22-29, wherein a pressure is applied in the second direction during the second flow by a second pressure source.

31. The method of any one of claims 22-30, wherein the first flow and / or second flow has a flow rate of at least 0.01 mL per minute and up to 1000 mL / min.

32. The method of any one of claims 22-31, wherein the first flow and / or second flow has a flow rate of at least 2 mL per minute and up to 1000 mL / min.

33. The method of any one of claims 22-32, wherein a duty cycle of the first flow is at least 0.1% and 99.9% .

34. The method of any one of claims 22-33, wherein a duty cycle of the first flow to the second flow is at least 70% and 99.9%.

35. The method of any one of claims 22-34, wherein the first flow and / or second flow has a mean flow velocity of between 0.01 cm / s and 10,000 cm / s.

36. The method of any one of claims 22-35, wherein the first flow and / or second flow has a mean flow velocity of between 12 cm / s and 24 cm / s.

37. The method of any one of claims 22-36, further comprising subjecting the oocyte complex to repeated first flow and second flow through the fluidic channel in an alternating fashion.

38. The method of any one of claims 22-37, further comprising repeating the steps of first flow and second flow at least 2 times.

39. The method of any one of claims 22-38, further comprising repeating the steps of first flow and second flow at least 5 times.

40. The method of any one of claims 22-39, further comprising repeating the steps of first flow and second flow at least 10 times.

41. The method of any one of claims 22-40, wherein the repeating step is carried out at a rate of between 4 rounds of flow per minute to 60 rounds of flow per minute, wherein one round of flow comprises the first flow followed by the second flow.

42. The method of any one of claims 22-41, wherein the repeating step is carried out at a rate of between 0.1 rounds of flow per minute to 10,000 rounds of flow per minute, wherein one round of flow comprises the first flow followed by the second flow.

43. The method of any one of claims 22-42, further comprising trapping the oocyte complex subjected the first flow and / or the second flow in a region comprising an additional plurality of posts.

44. The method of claim 43, further comprising flowing denuded oocyte through the additional plurality of posts.

45. The method of any one of claims 22-44, further comprising measuring a denudation level of the oocyte within the sub-channel.

46. The method of any one of claims 22-45, further comprising releasing the oocyte when the denudation level of the oocyte reaches a predetermined threshold value.

47. The method of any one of claims 22-46, further comprising flowing the denuded oocytes through the capture region in the first direction, such that the denuded oocyte is released through an outlet of the device downstream of the capture region.

48. The method of any one of claims 22-47, further comprising flowing the denuded oocyte in the second direction, such that the denuded oocyte flows away from the capture region and is released through an outlet of the device upstream the capture region.

49. The method of any one of claims 22-48, further comprising flowing a chemical and / or an enzyme through the fluidic channel to facilitate denudation of oocyte.

50. A method of denuding an oocyte complex comprising an oocyte and non-oocyte cells to separate the oocyte from the non-oocyte cells, the method comprising: repeatedly causing flow of a fluid containing the complex through a fluidic channel, wherein at least 10% of the non-oocyte cells in the complex are removed during repeated flow of the complex through the fluidic channel.

51. The method of claim 50, wherein at least 50% of the non-oocyte cells in the complex are removed during repeated flow of the complex through the fluidic channel.

52. The method of any one of claims 50 or 51, wherein at least 90% of the non-oocyte cells in the complex are removed during repeated flow of the complex through the fluidic channel.

53. The method of any one of claims 50-52, wherein the fluidic channel comprises a plurality of posts defining sub-channels between neighboring pairs of posts.

54. The method of any one of claims 50-53, further comprising separating the oocyte from bounded non-oocyte cells by passing the oocyte through the plurality of sub- channels.

55. The method of any one of claims 50-54, wherein the flow of fluid is caused to oscillate repeatedly from a first direction to a second direction.

56. The method of claim 55, wherein the flow of fluid is caused to flow in a first direction from an inlet to an outlet of the fluidic channel, followed by a flow in the second direction from the outlet to the inlet of the fluidic channel.

57. The method of any one of claims 50-56, wherein the flow of fluid is caused to flow repeatedly in a clockwise or counterclockwise direction.

58. The method of any one of claims 50-57, wherein the fluidic channel is formed by concentric walls.

59. A method of manipulating an oocyte complex comprising an oocyte and non-oocyte cells, the method comprising: causing a flow of fluid containing the complex in a fluidic channel such that the complex flows across an imaginary line within the fluidic channel at least 2 times, wherein the imaginary line is defined in a direction orthogonal to a direction of bulk fluid flow within the fluidic channel.

60. The method of claim 59, wherein the complex flows across the imaginary line at least 5 times.

61. The method of any one of claims 59-60, wherein the complex flows across the imaginary line at least 10 times.

62. A method of manipulating an oocyte complex comprising an oocyte and non-oocyte cells, the method, comprising: causing a flow of fluid containing the complex in a channel dimensioned toallow the oocyte to flow through only if not bound to the non-oocyte cells; and repeating the causing step at least 2 times.

63. The method of claim 62, wherein the channel comprises a plurality of posts defining sub-channels sized to allow the oocyte to flow through only if not bound to the non- oocyte cells.

64. The method of any one of claims 62 or 63, wherein the plurality of sub-channels have a minimum cross-sectional dimension of between about 50 micrometers and about 180 micrometers.

65. The method of any one of claims 62-64, wherein the plurality of sub-channels have a minimum cross-sectional dimension of between about 80 micrometers and about 350 micrometers.

66. The method of any one of claims 62-65, wherein the causing step is repeated at least 5 times.

67. The method of any one of claims 62-66, wherein the causing step is repeated at least 10 times.

68. A method of denuding an oocyte from bounded non-oocyte cells in a fluid, comprising: inducing a first flow of the fluid containing one or more non-oocyte oocyte complex in a first direction through a microfluidic channel, such that at least a portion of the bounded non-oocyte cells is removed from the complex as the oocyte flows through the microfluidic channel in the first direction; and inducing a second flow of the fluid containing the one or more cumulous oocyte complex in a second direction opposite the first direction through the microfluidic channel, such that at least a portion of the bounded non-oocyte cells is removed as the oocyte flows through the microfluidic channel in the second direction.

69. A microfluidic device to process fluid and to isolate and denude oocytes for egg banking, egg freezing, and / or for in-vitro fertilization, comprising:a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts; a first pressure source upstream of the plurality of posts; and a second pressure source downstream of the plurality of posts.

70. The device of claim 69, wherein at least some of the sub-channels have a minimum cross-sectional dimension of between 50 micrometers and 180 micrometers.

71. The device of any one of claims 69-70, wherein at least some of the sub-channels have a minimum cross-sectional dimension of between 80 micrometers and 180 micrometers.

72. The device of any one of claims 69-71, wherein the sub-channels define a denuder region having a length within the fluidic channel of no more than 100 millimeters.

73. A microfluidic device, comprising: a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, wherein at least some of the sub-channels have a minimum cross-sectional dimension of between about 80 micrometers and about 350 micrometers, and wherein the sub-channels define a denuder region having a length within the fluidic channel of no more than 100 millimeters; a first pressure source upstream of the plurality of posts; and a second pressure source downstream of the plurality of posts.

74. The microfluidic device of claim 73, wherein the plurality of posts are arranged in an array across the channel.

75. The microfluidic device of any one of claims 73-74, wherein the array of posts comprises one or more rows of posts, and wherein each row comprises one or more posts.

76. The microfluidic device of any one of claims 73-75, wherein at least one of the plurality of posts comprises a shape selected from a kite-shaped structure, and / or a hexagon.

77. The microfluidic device of any one of claims 73-76, wherein some of sub-channels adjacent an inlet of the microfluidic device have minimum cross-sectional dimensions larger than the minimum cross-sectional dimensions of sub-channels further away from the inlet of the microfluidic device.

78. The microfluidic device of any one of claims 73-77, wherein some of the sub- channels have a minimum cross-sectional dimension of between 80 micrometers and 160 micrometers.

79. The microfluidic device of any one of claims 73-78, wherein some of the sub- channels have a minimum cross-sectional dimension of between 120 micrometers and 160 micrometers.

80. The microfluidic device of any one of claims 73-79, wherein some of the sub- channels may have a cross-sectional dimension of up to 1000 micrometers.

81. The microfluidic device of any one of claims 73-80, wherein at least a portion of the walls on the neighboring pairs of posts defining the sub-channels comprises a plurality of teeth.

82. The microfluidic device of claim 81, wherein at least some of the teeth has a shape selected from round, triangular, rectangular, saw-teeth, quadrilaterals, and / or polygons.

83. The microfluidic device of any one of claims 81-82, wherein at least some of the teeth are present on regions of the walls defining a minimum cross-sectional dimension of the sub-channel.

84. The microfluidic device of any one of claims 81-83, wherein at least some of the teeth are saw-teethed.

85. The microfluidic device of any one of claims 81-84, wherein at least some of the teeth are bi-directional.

86. The microfluidic device of any one of claims 81-85, wherein at least some of the teeth are uni-directional.

87. The microfluidic device of any one of claims 81-86, wherein at least some of the teeth are oriented facing a direction of bulk fluid flow across the sub-channel.

88. The microfluidic device of any one of claims 81-87, wherein a first set of teeth is oriented facing a first direction of bulk fluid flow across the sub-channel, and a second set of teeth is oriented facing a second direction of bulk fluid flow across the sub-channel.

89. The microfluidic device of any one of claims 81-88, where the inlet and / or outlet of the sub-channels are tapered.

90. The microfluidic device of any one of claims 73-89, further comprising a first inlet adjacent the first pressure source, and a second inlet adjacent the second pressure source.

91. The microfluidic device of any one of claims 73-90, further comprising an outlet downstream of the plurality of posts.

92. The microfluidic device of any one of claims 73-91, further comprising a plurality of posts defining a capture region disposed between the first inlet and the second inlet.

93. The microfluidic device of claim 92, wherein the capture region comprises a plurality of posts spaced apart at a distance of between 80 micrometers and 150 micrometers.

94. The microfluidic device of any one of claims 73-93, wherein the first pressure source and / or second pressure source comprises one or more pumps.

95. The microfluidic device of any one of claims 73-94, wherein the first pressure source is configured to exert a pressure in a first direction, and the second pressure source is configured to exert a pressure in a second direction.

96. The microfluidic device of any one of claims 73-95, further comprising an outlet downstream the fluidic channel and configured to output denuded oocyte from the device.

97. The microfluidic device of any one of claims 73-96, further comprising a closed-loop controller configured to control one or more components associated with the device based on a measured parameter within the device.

98. The microfluidic device of any one of claims 73-97, further comprising one or more fluid control valves associated with the first and / or second inlet.

99. The microfluidic device of any one of claims 73-98, wherein the measured parameter is the denudation level of the oocyte, and the one or more components comprise the one or more pressure sources, the one or more inlets, the outlet, the one or more fluid control valve.

100. The microfluidic device of any one of claims 73-99, wherein the fluidic channel is formed by concentric walls.

101. A microfluidic device, comprising: a fluidic channel having an inlet and an outlet, wherein the fluidic channel has a minimum cross-sectional dimension of between about 80 micrometers and about 350 micrometers; a plurality of posts downstream of the fluidic channel, the posts spaced apart at a distance of no more than 120 micrometers; a first pressure source upstream of the plurality of posts; and a second pressure source downstream of the plurality of posts.

102. The microfluidic device of claim 101, wherein the plurality of posts downstream of the fluidic channel comprises at least one row of posts.

103. The microfluidic device of any of claims 101-102, further comprising a first pressure source upstream of the plurality of posts.

104. The microfluidic device of claim 103, further comprising a second pressure source downstream of the plurality of posts.

105. The microfluidic device of any of claims 101-104, further comprising a first outlet downstream of the plurality of posts.

106. The microfluidic device of any of claims 101-105, wherein the posts define one or more sub-channels having a minimum cross-sectional dimension that is less than the minimum cross-sectional dimension of the fluidic channel.

107. A method of preparing a fluid to isolate and denude a target entity-secondary entity complex comprising a target entity and one or more secondary entities to separate the target entity from the secondary entities, the method comprising: passing the fluid through a fluidic channel comprising a plurality of posts such that the complex flows through sub-channels defined between neighboring pairs of posts.

108. The method of claim 107, wherein the fluid comprises culture media.

109. The method of any one of claims 107 or 108, wherein the fluid comprises follicular media.

110. A method of denuding a target entity-secondary entity complex comprising a target entity and one or more secondary entities to separate the target entity from the secondary entities, the method comprising: passing the complex through a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, at least one of the sub- channels having a minimum cross-sectional dimension of between about 1 micrometer and about 1 mm, the sub-channels defining denuder region having a length within the fluidic channel of no more than 100 millimeters, such that at least 10% of the secondary entities are removed when the complex flows through sub- channels.

111. The method of claim 110, wherein at least 50% of the secondary entities are removed when the complex flows through sub-channels.

112. The method of any one of claims 110-111, wherein at least 90% of the secondary entities are removed when the complex flows through sub-channels.

113. The method of any one of claims 110-112, wherein at least one of the sub-channels having a minimum cross-sectional dimension of between about 30 micrometers and about 1 mm.

114. A method of manipulating a target entity-secondary entity complex comprising an target entity and one or more secondary entities, the method comprising: causing a flow of fluid containing the complex in a fluidic channel comprising a plurality of posts defining sub-channels between neighboring pairs of posts, such that the complex passes the plurality of posts at least 2 times.

115. The method of claim 114, wherein the complex passes the plurality of posts at least 5 times.

116. The method of any one of claims 114-115, wherein the complex passes the plurality of posts at least 10 times.

117. A method of denuding an target entity-secondary entity complex comprising an target and one or more secondary entities to separate the target from the one or more secondary entities, the method comprising: causing a first flow of a fluid containing the complex in a first direction through a fluidic channel; removing at least some of the one or more secondary entities from the complex as the complex flows through the fluidic channel in the first direction; causing a second flow of the fluid containing the complex in a second direction through the fluidic channel; and removing at least some of the one or more secondary entities from the complex as the complex flows through the fluidic channel in the second direction.

118. A method of denuding an target entity-secondary entity complex comprising an target entity and one or more secondary entities to separate the target entity from the one or more secondary entities, the method comprising: repeatedly causing flow of a fluid containing the complex through a fluidic channel, wherein at least 10% of the one or more secondary entities in the complex are removed during repeated flow of the complex through the fluidic channel.

119. The method of claim 118, wherein at least 50% of the one or more secondary entities in the complex are removed during repeated flow of the complex through the fluidic channel.

120. The method of any one of claims 118-119, wherein at least 90% of the one or more secondary entities in the complex are removed during repeated flow of the complex through the fluidic channel.

121. A method of manipulating an target entity-secondary entity complex comprising an target entity and one or more secondary entities, the method comprising: causing a flow of fluid containing the complex in a fluidic channel such that the complex flows across an imaginary line within the fluidic channel at least 2 times, wherein the imaginary line is defined in a direction orthogonal to a direction of bulk fluid flow within the fluidic channel.

122. The method of claim 121, wherein the complex flows across the imaginary line at least 5 times.

123. The method of any one of claims 121-122, wherein the complex flows across the imaginary line at least 10 times.

124. A method of manipulating an target entity-secondary entity complex comprising an target entity and one or more secondary entities, the method comprising: causing a flow of fluid containing the complex in a channel dimensioned to allow the target entity to flow through only if not bound to the one or more secondary entities; and repeating the causing step at least 2 times.

125. A method of denuding an target entity from bounded one or more secondary entities in a fluid, comprising: inducing a first flow of the fluid containing one or more target entity- secondary entity complex in a first direction through a microfluidic channel, such that at least a portion of the bounded one or more secondary entities is removed as the target entity flows through the microfluidic channel in the first direction; and inducing a second flow of the fluid containing the one or more target entity- secondary entity complex in a second direction opposite the first direction through the microfluidic channel, such that at least a portion of the bounded one or more secondary entities is removed as the target entity flows through the microfluidic channel in the second direction.

126. The device and / or method of any one of the preceding claims, wherein the non-oocyte cells comprise one or more of cumulus cells, granulosa cells, mural cells, thecal cells, red blood cells, or combinations thereof.

127. The device and / or method of any one of the preceding claims, wherein the microfluidic device is defined by a circular form factor.

128. The device and / or method of any one of the preceding claims, wherein the plurality of posts has a wall angle of between 2 degrees and 10 degrees, relative to an axis that is perpendicular to a bottom surface of the microfluidic device.

129. The device and / or method of any one of the preceding claims, wherein a cross- sectional dimension of a first portion of a trapezoidal-like sub-channel is larger than the cross-sectional dimension of a second portion of the trapezoidal-like sub-channel.

130. The device and / or method of any one of the preceding claims, wherein a cross- sectional dimension of the first portion of the trapezoidal-like sub-channel is smaller than the cross-sectional dimension of the second portion of the trapezoidal-like sub- channel131. The device and / or method of any one of the preceding claims, wherein the trapezoidal-like sub-channels has an average cross-sectional dimension of between 10 microns and 200 microns.

132. The device and / or method of any one of the preceding claims, wherein the average cross-sectional dimension of the sub-channels in the denuder region is between 10 microns and 200 microns and the average cross-sectional dimension of the sub- channels in the capture region is between 10 microns and 200 microns.

133. The device and / or method of any one of the preceding claims, wherein the plurality of sub-channels has an average height of between 100 microns and 400 microns.

134. The device and / or method of any one of the preceding claims, wherein the average height of the sub-channels in the denuder region is between 100 microns and 400 microns and the average height of the sub-channels in the capture region is between 100 microns and 400 microns.

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