CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63/336,632 filed on April 29, 2022, the content of which is relied upon and incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present specification generally relates to methods of manufacture of flasks for use in cell culture and particularly relates to methods of flask manufacture that reduce or eliminate meld lines.

BACKGROUND

[0003] T flasks are traditional flasks used for cell culture. Typically, such flasks are optically clear or transparent in order to view the cell culture happening within the flask. During manufacturing of the flasks, process steps may result in meld line formation. Meld lines are undesirable, as meld lines are typically opaque, thus preventing the flask from being transparent and hindering the user in viewing the cell culture happening within the flask.

SUMMARY

[0004] The present subject matter is directed to methods of designing cell culture flasks that are meld-line free.

[0005] According to an aspect, a method of determining whether a design of a cell culture flask will be meld line-free is provided. The method comprises: training a machine learning model on cell culture flask design parameter data; inputting parameters of a flask design into a machine learning model; and determining whether the flask design will be meld line-free, based on output from the machine learning model.

[0006] In an embodiment, cell culture flask design parameter data comprises data obtained by varying geometric parameters of cell culture flasks.

[0007] In an embodiment, the cell culture flasks comprise U225 and U25 cell culture flasks. [0008] In an embodiment, the geometric parameters comprise ratios of geometric parameters.

[0009] In an embodiment, the ratios of geometric parameters comprise: width panel (Wp) to length of panel (Lp); width of sidewall (Ws) to length of sidewall (Ls); thickness of panel (Tp) to thickness of sidewall (Ts); thickness of panel (Tp) to thickness of rib (Tr); width of rib (Wr) to length of rib (Lr); and length of panel (Lp) to length of sidewall (Ls).

[0010] In an embodiment, multiple values of each parameter were tried in all possible combinations.

[0011] In an embodiment, training further comprises evaluating each design obtained by varying the geometric parameter for its meld line formation tendency by running it through a numerical model.

[0012] In an embodiment, training further comprises conducting a comprehensive numerical design of experiments (DOE) to generate the data on which the machine learning model was trained on.

[0013] In an embodiment, the cell culture flask comprises: a panel; a bottom arranged parallel to the panel; a plurality of sidewalls extending between the panel and the bottom, wherein a sidewall disposed at a first end of the flask comprises an endwall, wherein each sidewall has a sidewall length (Ls), sidewall thickness (Ts), and sidewall width (Ws); a neck portion disposed at an opposite second end of the flask; a rib disposed along at an outer perimeter of the panel, the rib extending upwards from an exterior surface of the panel; and an interior chamber defined by interior surfaces of the panel, the bottom, the plurality of sidewalls, and the neck portion. In an embodiment, the rib surrounds the entire outer perimeter of the panel.

[0014] In an embodiment, the panel comprises a panel length (Lp), a panel thickness (Tp), and a panel width (Wp).

[0015] In an embodiment, each sidewall of the plurality of sidewalls comprises a sidewall length (Ls), sidewall thickness (Ts), and sidewall width (Ws).

[0016] In an embodiment, the rib comprises a rib length (Lr), rib thickness (Tr), and rib width (Wr).

[0017] In an embodiment, the cell culture flask comprises a U-shaped flask. In an embodiment, the U-shaped flask comprises a canted neck. In an embodiment, the U-shaped flask comprises an angled neck. In an embodiment, the U-shaped flask comprises a straight neck. [0018] In an embodiment, the cell culture flask comprises a T-shaped flask. In an embodiment, the T-shaped flask comprises a canted neck. In an embodiment, the T-shaped flask comprises an angled neck. In an embodiment, the T-shaped flask comprises a straight neck.

[0019] In an embodiment, the cell culture flask comprises a rectangular flask. In an embodiment, the rectangular flask comprises a canted neck. In an embodiment, the rectangular flask comprises an angled neck. In an embodiment, the rectangular flask comprises a straight neck.

[0020] According to an aspect, a cell culture flask designed according to the methods described herein. In an embodiment, the cell culture flask comprises a U-shaped flask, a T- shaped flask, or a rectangular flask.

[0021] Additional features and advantages of the embodiments described herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0022] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description, serve to explain the principles and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows perspective view of a flask according to embodiments described herein.

[0024] FIG. 2 shows a cross-sectional view of inset Box A of the flask of FIG. 1 according to embodiments described herein.

[0025] FIG. 3 shows an image of a U75 flask according to embodiments described herein.

[0026] FIG. 4 shows a perspective view of a U225 flask and a U25 flask according to embodiments described herein.

[0027] FIG. 5 shows a distribution chart of design cases, where the length ratio (Lp/Ls) is on the Y axis and the thickness ratio (Tp/Ts) is on the X axis according to embodiments described herein.

[0028] FIG. 6 shows a bar chart countplot of cases with thickness ratio (Tp/Ts) as 1 segregated by length ratio (Lp/Ls) according to embodiments described herein.

[0029] FIG. 7 shows a graph of input parameter model coefficients according to embodiments described herein.

[0030] FIG. 8 shows a top view of a rectangular flask according to embodiments herein. [0031] FIG. 9 shows a top view of an angled neck T flask according to embodiments herein.

[0032] FIG. 10 shows a top view of a U-shaped flask according to embodiments herein. [0033] FIG. 11 shows a side view of a straight neck flask according to embodiments herein. [0034] FIG. 12 shows a side view of a canted neck flask according to embodiments herein. [0035] FIG. 13 shows a side view of an angled neck flask according to embodiments herein.

[0036] Reference will now be made in detail to embodiments of systems and methods of producing cell culture scaffolds, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

DETAILED DESCRIPTION

[0037] T flasks and U flasks are available from Corning Life Sciences (Coming Incorporated, Corning, NY). The U flasks comprise redesigned T flasks with reduced material usage per flask. However, during the prototyping stage of U75, meld lines were observed on the bottom corners of the panel. Similarly, numerical modeling of U175 and U225 also showed that meld lines are formed on the panel. However, numerical modeling of the U25 flask showed no such meld line formation. Thus, a detailed understanding behind the formation of such meld lines was carried out, leading to the methods described herein, which allow for assessing whether a flask is susceptible to meld line formation.

[0038] Design measures that may be adopted to avoid meld line formation were identified through injection molding numerical modeling. For example, if the panel thickness is higher than the side wall thickness by a certain amount, meld line formation could be completely avoided. As another example, meld line formation may also be avoided by changing the gate location such that flow length reduces. However, both of those findings were obtained through numerical modeling - setting up a numerical model to test if a flask design is meld line-free is not only time-consuming, but also requires a specialist. Therefore, a quick and inexpensive method is needed that allows for assessing the tendency of meld line formation on a flask panel.

[0039] The present disclosure illustrates methods and a related machine learning (ML) based model that can be used to quickly evaluate a flask design for its meld line formation tendency. Further, the methods and ML model can be used by a design team that would allow for the design to be changed at the source (i.e., design team) resulting in significant time savings by avoiding various downstream design iterations between various teams (i.e., design team, modeling team, specialists, etc.).

[0040] The present disclosure describes an inexpensive and quick method to verify if the design of a flask is meld line-free. Meld lines are formed when two polymer flow fronts meet at an angle greater than 135°. In the context of cell culture flasks, meld lines were observed in manufacturing cell culture flasks such as U75, U175, and U225 (Coming Incorporated, Corning, NY). The identification of meld line formation was done at a downstream step, such as the prototyping stage of U75, which led to time-consuming design iterations that involved multiple technical teams to avoid formation of meld lines.

[0041] The method herein is a simple and effective way to check the meld line formation tendency in a flask. It is simple enough to be used by a design team to verify if a design is meld line-free at the source, thereby avoiding time-consuming downstream design iterations. [0042] The proposed method is based on a machine learning (ML) model. The ML model is trained on data obtained by varying geometric parameters of the U225 and U25 cell culture flasks. These two flasks were chosen as they are based on a common design philosophy and yet, U225 displays meld line formation tendency but U25 does not. The panel thickness and panel length were varied in both the flasks, and multiple values of each parameter were tried in all possible combinations. Every design so obtained by varying the geometric parameter was then evaluated for its meld line formation tendency by running it through a numerical model. Thus, a comprehensive numerical design of experiments (DOE) was done to generate the data on which the machine learning model was trained on. After the model has been successfully trained, it can be used by anyone to evaluate the meld line formation tendency on the panel of a cell culture flask. A particular advantage of using this model is that its applicability is not limited to the flask designs that it was trained on. If the U flasks are again redesigned in the future, the ML model can be used by the design team to even evaluate the future redesigns. Thus, the need to setup a numerical model to evaluate any new flask with respect to its meld line formation tendency is done away with.

[0043] Since this method is based on a machine learning (ML) model that has been trained on exhaustive values of geometric parameters, its usage is not limited to the flasks on which it was trained on. It can be used to check the meld line formation tendency for any future flask as well. Moreover, unlike numerical modeling, a specialist is not required to use the ML model to verify that the flask panel design is meld line free. It can be used by a design team to quickly verify the design and accordingly change the design, if necessary. Thus, because a design team can use the model to assess the panel design at the source of design, time consuming downstream design revisions with multiple technical teams may be avoided by using methods described herein.

[0044] T flasks (or T-shaped flask) cell culture flasks were redesigned as U flasks (or U- shaped flasks) to increase material savings. FIG. 1 and FIG. 2 illustrate the U225 flask lid and base, and show the terminology or nomenclature used to refer to different regions of the flask 100. FIG. 2 shows a cross-sectional view of Box A of FIG. 1. The flask 100 comprises a bottom 105 and a top or panel 110 disposed opposite to and parallel to the bottom 105. The top or panel 110 and the bottom 105 are flat or substantially flat. A rib 145 is disposed at a perimeter of the top or panel 110 and extends upwards or away from a surface of the panel 110. At least one side wall 125 extends from the top 110 to the bottom 105 and is disposed perpendicular to the top 110 and bottom 105 at a side of the top or bottom. In FIG. 1, two side walls 125 are disposed parallel to and opposite each other on either side of the flask 100, extending from a first end 141 of the flask 100 to a second end 143 of the flask 100.

Moreover, an end wall is disposed at the first end 141 of the flask 100 and extends from the top 110 to the bottom 105, disposed perpendicular to the top 110 and bottom 105, and arranged perpendicular to side walls 125. At the opposite second end 143, the flask comprises a neck region 120. The neck region 120 comprises a canted neck wall 125 with a neck 130 and an aperture 135 allowing access to an internal volume of the flask 100. The neck 130 comprises threading 133 configured for operation with a cap or lid. Panel thickness (Tp), panel length (Lp), panel width (Wp), side wall thickness (Ts), side wall length (Ls), side wall width (Ws), rib thickness (Tr), rib length (Lr), and rib width (Wr) are also designated.

[0045] FIG. 3 illustrates meld lines 150 observed during a prototyping stage of U75, a U- shaped flask having a 75 cm ² surface area. To reduce material usage, the U75 flask panel 110 and side wall 125 were of equal thickness. On further study of these meld lines through numerical simulations, it was realized that meld lines form when the polymer flow from the side wall and rib enters the panel. This happens as the flow front in the panel lags behind the flow front in the side wall and rib due to the high flow resistance of the panel. Through numerical modeling done in Autodesk Moldflow, it was learned that the meld lines may be completely eliminated if the panel thickness is greater than the side wall thickness by a certain critical amount. Making the panel thicker reduces its flow resistance, which allows the flow front in the panel to lead the flow front in the side wall and rib. However, a thicker panel leads to additional material consumption. To avoid the extra material consumption, additional efforts were made to learn that a meld line-free panel could also be made by decreasing the panel length, thereby decreasing its flow resistance. Decreasing the panel length allows for keeping the thickness of the panel equal to the thickness of the side wall while still reducing the material usage.

[0046] The learnings obtained through numerical modeling may be applied to obtain a meld line-free flask design. However, to verify if a flask design is indeed meld line-free, a numerical model in Autodesk Moldflow must first be made that would predict meld line formation. Setting up a numerical model is time-consuming and requires a specialist. Hence, if a future flask design has to be evaluated with respect to meld line formation tendency, it will not only require extra technical resources, but also additional time. In contrast, the machine learning (ML) based method disclosed herein quickly evaluates if the flask design is meld line-free. Further, the method disclosed herein is simple enough that a design team may use the method to evaluate a design, thereby allowing for a design change at the source. As such, the method disclosed herein may lead to significant time savings, as downstream design iterations between various technical teams may be completely avoided.

[0047] Meld lines occur when the flow front in the panel lags behind the flow front in the side wall which allows the melt to enter into the panel from the ribs. Increasing the panel thickness and decreasing the length of the panel were both identified as ways to reduce the panel flow resistance and key techniques to design a meld line-free panel. Thus, the primary geometric parameters that play a role in meld line formation are panel thickness and panel length. These parameters will be given as input to the ML model that would ultimately predict if a flask would display a meld line given its geometric parameters.

[0048] Before discussing the details of the ML model, it is important to understand the capabilities and limitations of ML based predictive classification models. The most important limitation of any such model is that it cannot make predictions on the basis of data that it has not seen or been trained on before. This means that if an ML model is trained on the absolute values of the geometric parameters of the U-shaped cell culture flasks, it will not be applicable to flasks that are designed with dimensions considerably different from the U- shaped cell culture flasks. For example, if a flask has every dimension twice as that of a typical U-shaped cell culture flask, the ML model cannot predict if that flask is prone to meld line formation, as it has not been trained to make predictions on such large flasks. A simple technique to circumvent this limitation is to train the ML model on ratios of geometric parameters rather than the absolute values of the parameters since the ratios of parameters will lie in a typical range, no matter how small or large a flask is. Further, it is even more advantageous to form ratios of those dimensions that have physical importance. For example, formation of a meld line is dictated by the panel flow resistance and its value in comparison to the side wall and rib flow resistance. Thus, the ratio of these flow resistances is physically important, which in turn depends on the ratio of panel thickness (Tp) to side wall thickness (Ts), panel thickness (Tp) to rib thickness (Tr), and panel length (Lp) to the side wall length (Ls). A separate ratio of panel length (Lp) to the rib length (Lr) was not considered since rib length (Lr) is very similar to side wall length (Ls). These ratios are referred to as thickness and length ratios. Training the ML model on such geometric ratios will make it universally applicable and future proof.

[0049] Apart from the thickness and length ratios, the ratio of panel width (Wp) to its length (Lp), side wall width (Ws) to its length (Ls), rib width (Wr) to its length (Ls) are also given as inputs to the ML model. This is done as the width of the panel/ side wall/ rib can affect the flow development length in the panel/ side wall/ rib respectively. This will further affect the flow fronts in the panel/ side wall/ rib and hence contribute towards meld line formation. Thus, the ML model has 6 inputs, and the nomenclature used to refer to the geometric features comprising the 6 input ratios is illustrated in figure 1. For any given values of these 6 inputs, the model predicts if that flask panel is meld line free or not.

[0050] Model Development & Data Analysis

[0051] To train the ML model, 2 flasks were chosen - U25 and U225 - as shown in FIG. 4. These two particular flasks were chosen because U25 did not show any meld lines in numerical simulations but U225 did, even though both of these flasks were designed on the same principles. Further, since both these flasks are significantly different with respect to overall dimensions, varying their geometric parameters to feed to the ML model will ensure a wide coverage of input parameters. Both these flasks are illustrated in FIG. 4 and their respective geometric parameters are detailed in Table 1.

Table 1: Geometric Parameters of U225 and U25

[0052] For both of these flasks, the panel thickness and panel length were varied and multiple values were tried for each parameter. For every new case, a numerical model was setup in Autodesk Moldflow to verify if the new generated design is meld line free or not. Along with the 6 geometric parameter ratios, the meld line result would be fed to the ML model for training. In total, 339 different cases for U25 and U225 were tested for meld line formation, of which 305 cases were used to train the ML model and 34 were used to test it. Table 2 depicts the range of values for every input ratio, and it is clearly evident that a sufficiently wide range has been covered for every input ratio. This allows the model to be applicable on flasks that are different from the base U25 and U225 designs.

Table 2: Value Range of Input Ratios to ML Model [ | | i g

[0053] Since the model was used to make a prediction on the basis of values of certain geometric parameter ratios, a logistic regressor was used. Additionally, a preliminary data analysis was also performed on all the cases.

[0054] FIG. 5 shows a graph of the distribution of all the design cases with the length ratio (Lp/Ls) on the Y axis and the thickness ratio (Tp/Ts) on the X axis, wherein the points are color coded as light grey for presence of a meld line (1) and as dark grey for absence of a meld line (0). From FIG. 5, it can clearly be seen that in general, as the panel to side wall thickness ratio increases, meld line formation decreases. Further, it can be seen from FIG. 5 that above or below a certain thickness ratio, meld lines are either always formed or never formed. In the region around the thickness ratio of 1, the length ratio also seems to be playing a role - meld lines are generally absent for lower values of the length ratio and present for higher values.

[0055] FIG. 6 shows a countplot of all the cases with thickness ratio (Tp/Ts) as 1 segregated by the length ratio (Lp/Ls). The bars are color coded as light grey for presence of a meld line (1) and as dark grey for absence of a meld line (0). As shown in FIG. 6, the plot strongly suggests that for length ratio of 0.8 and below, meld lines are not formed if the thickness ratio is 1. Similar plots are seen when the panel/rib thickness ratio is considered instead of the panel/sidewall thickness ratio, and hence not shown to avoid redundancy.

[0056] Model Results, Validation., and Testing

[0057] The ML model was trained on 305 cases comprised of variations of U25 and U225 base designs obtained by changing either the panel length and/or the panel thickness. FIG. 7 illustrates the importance of the input parameters in deciding if a flask panel is meld line free or not through their model coefficient values. Basically, the larger the absolute value of the coefficient, the higher its impact is in deciding meld line presence. As expected, both the thickness ratios are the most influential factors followed closely by the length ratio. As for the sign of the coefficients, that just shows the nature of dependence of meld line on them - positive coefficients imply direct relationship and negative coefficients imply inverse relationship. For example, higher the value of Lp/Ls, higher is the chance of meld line formation (since meld line presence is numerically depicted as 1 in the model). Conversely, higher the value of Tp/Ts, lower is the chance of meld line formation (since meld line absence is numerically depicted as 0 in the model). This is in line with the previous numerical modeling learnings which showed that making a panel thicker than the side wall/ rib and/ or decreasing the panel flow length leads to a meld line free flask.

[0058] After the model training is complete, the model is validated on 34 designs of U25 and U225. The model accurately predicts meld line formation for each of the 34 test cases. While making predictions is reasonably simple for cases that have panel/ sidewall or panel/ rib thickness ratio significantly higher or lower than 1, it is quite difficult for cases that have the thickness ratios just around 1. It is even more difficult to predict for the outlier cases i.e., cases with thickness ratio more than one but showing meld line and vice versa. Table 3 illustrates the geometric input ratios of such outlier cases that the machine learning model was able to predict correctly. Although validating the model on 34 cases is not exhaustive, the range of values covered for each input ratio in the validation cases is almost as wide as the total range of each of the input ratios. This strongly suggests that the model will perform well even on a larger validation set.

Table 3: Geometric input ratios of the outlier cases used to validate the ML model

[0059] The model was tested on flasks other than the U-shaped cell culture flasks U25 (25 cm ² surface area) and U225 (225 cm ² surface area). Designs of U-shaped cell culture flasks including U75 (75 cm ² surface area), U150 (150 cm ² surface area), U175 (175 cm ² surface area), and traditional T-flask T175 (175 cm ² surface area) were used to carry out the testing. Table 4 shows the design details of these flasks in terms of the geometric input ratios used by the ML model.

Table 4: Geometric input ratios of the flask designs used to test the ML model

[0060] Interestingly, as shown above in Table 4, both the designs of U75 (U75 design 1, U75 design 2) have Tp/Ts slightly more than 1 yet showed meld line formation. The model was able to correctly predict this, which otherwise could have only been verified via timeconsuming numerical modeling. Further, the model also correctly predicted the absence of meld line formation in the T175 flask, which is a different style of cell culture flask than the U-shaped flasks. This demonstrates that the ML model is indeed universally applicable and can be used to assess the design of the future generation flasks.

[0061] The flask may comprise any suitable shape that allows for cell culture within a volume of the flask. The neck of the flask may be any suitable style that allows for cell culture. The flask may further be releasably sealed during cell culture.

[0062] In an embodiment, the flask comprises a rectangular flask (FIG. 8). The rectangular flask may have a ramp from the bottom to a canted neck for easier pouring and pipet access. The canted neck flask may further comprise an anti-tip skirt to enhance stability.

[0063] In an embodiment, the flask comprises an angled neck T flask (FIG. 9). In an embodiment, the flask comprises a traditional straight neck flask. Angled neck flasks and traditional straight neck flasks use the entire bottom area for cell growth, the design thereby saving space and reducing medium sloshing into the neck.

[0064] In an embodiment, the flask comprises a U-shaped flask (FIG. 10). U-shaped flasks comprise rounded shoulders in a “U-shape” for an easier grip and better access when removing or tightening the cap. The ergonomic shape reduces the number of corners, improves cell scraping, and allows the use of a larger pipet.

[0065] In an embodiment, the neck may comprise a straight neck (FIG. 11). Straight neck flasks are ideal for larger medium volumes since this design reduces medium sloshing into the cap. [0066] In an embodiment, the neck may comprise a canted neck (FIG. 12). Canted neck flasks may allow for easier pouring and improved access to the flask for pipetting or scraping. [0067] In an embodiment, the neck may comprise an angled neck (FIG. 13). Angled neck flasks may improve pipet access and reduce medium sloshing into the neck.

[0068] The flask may be releasably sealed by a lid or cap by means of threads. For example, the flask may comprise threads configured to interlock with threads on a lid or cap. Any suitable cap may be used. Non-limiting examples of lids or caps include plug seal caps, phenolic-style caps, and vent caps. Plug seal caps feature one-piece linerless construction and are designed for use in closed systems, providing a liquid- and gas-tight seal. When loosened, this cap can also be used in open systems. Phenolic-style caps are designed (when loosened) for use in open systems requiring gas exchange. With the caps slightly loosened, gas is exchanged between the environments inside and outside of the flask. Vent caps may contain a 0.2 pm pore, hydrophobic membrane sealed to the cap, isolating the container it is placed on from the environment while providing consistent gas exchange. These caps are highly recommended for use in all CO2 incubators, especially for long-term use.

[0069] In a first aspect (aspect 1), a method of determining whether a design of a cell culture flask will be meld line-free is provided. The method comprises: training a machine learning model on cell culture flask design parameter data; inputting parameters of a flask design into a machine learning model; and determining whether the flask design will be meld line-free, based on output from the machine learning model.

[0070] In a second aspect (aspect 2), cell culture flask design parameter data comprises data obtained by varying geometric parameters of cell culture flasks.

[0071] In a third aspect (aspect 3), the cell culture flasks comprise U225 and U25 cell culture flasks.

[0072] In a fourth aspect (aspect 4), the geometric parameters comprise ratios of geometric parameters.

[0073] In a fifth aspect (aspect 5), the ratios of geometric parameters comprise: width panel (Wp) to length of panel (Lp); width of sidewall (Ws) to length of sidewall (Ls); thickness of panel (Tp) to thickness of sidewall (Ts); thickness of panel (Tp) to thickness of rib (Tr); width of rib (Wr) to length of rib (Lr); and length of panel (Lp) to length of sidewall (Ls). [0074] In a sixth aspect (aspect 6), multiple values of each parameter were tried in all possible combinations.

[0075] In a seventh aspect (aspect 7), training further comprises evaluating each design obtained by varying the geometric parameter for its meld line formation tendency by running it through a numerical model.

[0076] In an eighth aspect (aspect 8), training further comprises conducting a comprehensive numerical design of experiments (DOE) to generate the data on which the machine learning model was trained on.

[0077] In a ninth aspect (aspect 9), the cell culture flask comprises: a panel; a bottom arranged parallel to the panel; a plurality of sidewalls extending between the panel and the bottom, wherein a sidewall disposed at a first end of the flask comprises an endwall, wherein each sidewall has a sidewall length (Ls), sidewall thickness (Ts), and sidewall width (Ws); a neck portion disposed at an opposite second end of the flask; a rib disposed along at an outer perimeter of the panel, the rib extending upwards from an exterior surface of the panel; and an interior chamber defined by interior surfaces of the panel, the bottom, the plurality of sidewalls, and the neck portion.

[0078] In a tenth aspect (aspect 10), the rib surrounds the entire outer perimeter of the panel.

[0079] In an eleventh aspect (aspect 11), the panel comprises a panel length (Lp), a panel thickness (Tp), and a panel width (Wp).

[0080] In a twelfth aspect (aspect 12), each sidewall of the plurality of sidewalls comprises a sidewall length (Ls), sidewall thickness (Ts), and sidewall width (Ws).

[0081] In a thirteenth aspect (aspect 13), the rib comprises a rib length (Lr), rib thickness (Tr), and rib width (Wr).

[0082] In a fourteenth aspect (aspect 14), the cell culture flask comprises a U-shaped flask. [0083] In a fifteenth aspect (aspect 15), the U-shaped flask comprises a canted neck.

[0084] In a sixteenth aspect (aspect 16), the U-shaped flask comprises an angled neck. [0085] In a seventeenth aspect (aspect 17), the cell culture flask comprises a T-shaped flask.

[0086] In an eighteenth aspect (aspect 18), the T-shaped flask comprises a canted neck. [0087] In a nineteenth aspect (aspect 19), the T-shaped flask comprises an angled neck. [0088] In a twentieth aspect (aspect 20), the cell culture flask comprises a rectangular flask. [0089] In a twenty-first aspect (aspect 21), the rectangular flask comprises a canted neck. [0090] In a twenty-second aspect (aspect 22), the rectangular flask comprises an angled neck.

[0091] In a twenty-third aspect (aspect 23), a cell culture flask designed according to the methods described herein.

[0092] In a twenty-fourth aspect (aspect 24), the cell culture flask comprises a U-shaped flask, a T-shaped flask, or a rectangular flask.

[0093] It will be appreciated that the various disclosed embodiments may involve particular features, elements, or steps that are described in connection with that particular embodiment. It will also be appreciated that a particular feature, element, or step, although described in relation to one particular embodiment, may be interchanged or combined with alternate embodiments in various non-illustrated combinations or permutations.

[0094] It is also to be understood that, as used herein the terms “the,” “a,” or “an,” mean “at least one,” and should not be limited to “only one” unless explicitly indicated to the contrary. Thus, for example, reference to “an opening” includes examples having two or more such “openings” unless the context clearly indicates otherwise.

[0095] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.

[0096] As used herein, "have," "having," "include," "including," "comprise," "comprising," or the like are used in their open-ended sense, and generally mean "including, but not limited to."

[0097] Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, examples include from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0098] All numerical values expressed herein are to be interpreted as including “about,” whether or not so stated, unless expressly indicated otherwise. It is further understood, however, that each numerical value recited is precisely contemplated as well, regardless of whether it is expressed as “about” that value. Thus, “a dimension less than 10 mm” and “a dimension less than about 10 mm” both include embodiments of “a dimension less than about 10 mm” as well as “a dimension less than 10 mm.” [0099] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.

[00100] While various features, elements or steps of particular embodiments may be disclosed using the transitional phrase “comprising,” it is to be understood that alternative embodiments, including those that may be described using the transitional phrases “consisting” or “consisting essentially of,” are implied. Thus, for example, implied alternative embodiments to a method comprising A+B+C include embodiments where a method consists of A+B+C, and embodiments where a method consists essentially of A+B+C.

[00101] Although multiple embodiments of the present disclosure have been described in the Detailed Description, it should be understood that the disclosure is not limited to the disclosed embodiments, but is capable of numerous rearrangements, modifications and substitutions without departing from the disclosure as set forth and defined by the following claims.