Tangential virus filtration

Abstract

A virus filter includes a filter member characterized by a first surface and a second surface and having a thickness extending between the first surface and the second surface in a first direction, and a plurality of channels formed in the filter member, each of the channels having a channel axis, wherein during use, a solution carrying a viral load flows in a direction parallel to the first surface, and at least a portion of the viral load enters a membrane through the first surface and propagates in the first direction, and wherein for at least 50% of the channels in the filter member, the channel axis is oriented at an angle between 5 degrees and 85 degrees relative to the first direction.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 816,786, filed March 11, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This published text relates to biotechnology and biomanufacturing. Background Technology

[0004] Mammalian cells containing nucleic acids encoding recombinant proteins are commonly used to produce proteins that are therapeutically or commercially important. In today's diversified product pipeline environment, biotechnology companies are increasingly focused on developing innovative solutions for the highly flexible and cost-effective manufacture of therapeutic protein drug substances. Summary of the Invention

[0005] To perform biomanufacturing at production scale, multiple unit operations are implemented as continuous processes. Removing viruses from the product stream between these processes remains a challenging operation. This disclosure features systems and methods for implementing tangential flow viral filtration (TFVF). In some embodiments, TFVF can be performed on a continuous or semi-continuous basis to allow for the online purification of a wide variety of therapeutic protein pharmaceutical substances, including recombinant therapeutic protein substances. In a TFVF system, a fluid (e.g., a process fluid comprising one or more products to be purified) can be circulated through a fluid loop including filter elements that capture or retain viral particles. A portion of the fluid and its contents is not passed through the filter but is recirculated for another pass through the system.

[0006] In one aspect, this disclosure features a virus filter comprising: a filter member characterized by a first surface and a second surface and having a thickness extending between the first surface and the second surface in a first direction; and a plurality of channels formed in the filter member, each channel having a channel axis, wherein during use, a solution carrying a viral load flows in a direction parallel to the first surface, and at least a portion of the viral load enters a membrane through the first surface and propagates in the first direction, and wherein for at least 50% of the channels in the filter member, the channel axis is oriented at an angle between 5 degrees and 85 degrees relative to the first direction.

[0007] The implementation of the filter may include any one or more of the following features.

[0008] The channel axis is oriented at an angle between 5 and 75 degrees (e.g., between 10 and 60 degrees) relative to the first direction. For at least 70% of the channels in the filter member (e.g., for at least 90% of the channels), the channel axis is oriented at an angle between 5 and 85 degrees relative to the first direction.

[0009] The thickness of the filter component may be 150 micrometers or greater (e.g., 300 micrometers or greater, 500 micrometers or greater). Each member of the plurality of channels may include an opening at the first surface, and the ratio of the total area of ​​the openings to the total area of ​​the first surface may be 0.10 or greater (e.g., 0.20 or greater, 0.30 or greater). Each member of the plurality of channels may have a volume, and the ratio of the total volume of the channels to the total volume of the component may be 0.05 or greater (e.g., 0.10 or greater, 0.20 or greater).

[0010] For each of at least some members of the plurality of channels, the member channel includes an opening at the first surface, the opening having a first cross-sectional area in the first surface, and the first cross-sectional area may be smaller than a second cross-sectional area of ​​the member channel at a location between the first surface and the second surface. The ratio of the first cross-sectional area to the second cross-sectional area may be 0.95 or less (e.g., 0.85 or less, 0.75 or less). The at least some members may include at least 40% (e.g., at least 60%, all) of the members of the plurality of channels.

[0011] The channel axes of the plurality of channels may have an orientation distribution relative to the first direction. The average orientation of the distribution may be between 10 and 30 degrees relative to the first direction (e.g., between 30 and 50 degrees, or between 50 and 80 degrees). The full width at half maximum (FWHM) value of the orientation distribution may be 60 degrees or less (e.g., 40 degrees or less, or 15 degrees or less).

[0012] For each of at least some members of the plurality of channels, the member channel may include one or more secondary channels extending from the channel axis. The one or more secondary channels may extend from the channel axis along the secondary axis at an angle between 10 and 80 degrees relative to the channel axis. The one or more secondary channels may extend from the channel axis along the secondary axis at an angle between 50 and 90 degrees relative to the channel axis.

[0013] One or more member channels may include three or more (e.g., five or more) secondary channels. Each member channel may include an average of five or more (e.g., seven or more) secondary channels.

[0014] For each of at least some members of the plurality of channels, the member channel may include an opening at the first surface, the opening having a first cross-sectional area in the first surface and a maximum cross-sectional area different from the first cross-sectional area at a location between the first surface and the second surface. The ratio of the first cross-sectional area to the maximum cross-sectional area may be 0.50 or less (e.g., 0.30 or less, 0.10 or less).

[0015] The at least some members of the plurality of channels may include 50% or more (e.g., 80% or more) of the plurality of channels. For each of the at least some members of the plurality of channels, the member channel may include a maximum cross-sectional area and a minimum cross-sectional area at different locations along the channel axis, and the ratio of the minimum cross-sectional area to the maximum cross-sectional area may be 0.75 or less (e.g., 0.50 or less, 0.30 or less).

[0016] The first surface may be planar and may have a maximum dimension that can be measured in the plane, and the ratio of the maximum dimension to the thickness may be 10 or greater (e.g., 20 or greater). The porosity of the component may be between 0.3 and 0.9.

[0017] The component may be formed of a first material, and each of at least some members of the plurality of channels may include a second material located on the inner surface of the member channel. The first material may be selected from polyvinylidene fluoride (PVDF), hydrophilic PVDF, and regenerated cellulose. The second material may be selected from cellulose, polyethersulfone, and polyethylene glycol.

[0018] The ratio of the average thickness of the second material on the inner surface of the member channel to the maximum cross-sectional size of the member channel may be 0.2 or less (e.g., 0.1 or less, 0.05 or less, 0.02 or less).

[0019] The plurality of channels may be a first plurality of channels, and the filter component may include a first layer characterized by the first plurality of channels and a second layer characterized by a second plurality of channels. The second layer may contact the first layer. At the interface between the first layer and the second layer, at least some members of the first plurality of channels may be in fluid communication with at least some members of the second plurality of channels.

[0020] Each of the second plurality of channels may include a channel axis, and for at least 50% of the second plurality of channels in the second layer, the channel axis may be oriented at an angle between 5 degrees and 90 degrees relative to the first direction. The average orientation of the first plurality of channels relative to the first direction may differ from the average orientation of the second plurality of channels relative to the first direction.

[0021] The average angle between the channel axis and the first direction can be greater than the average angle between the channel axis and the first direction for the first plurality of channels. The average angle between the channel axis and the first direction for the second plurality of channels can be less than the average angle between the channel axis and the first direction for the first plurality of channels.

[0022] The first layer may be formed of a first material selected from polyvinylidene fluoride (PVDF), hydrophilic PVDF, and regenerated cellulose, and the second layer may be formed of a second material selected from cellulose and regenerated cellulose, polyethersulfone, polyethylene glycol, polyethylene, polypropylene, polystyrene, polypropylene glycol, polyurethane, polymethyl methacrylate, and polyacrylic acid. The first material and the second material may be different.

[0023] At least some of the first plurality of channels may include a coating material on the inner surface of the at least some channels. The coating material may be selected from cellulose, polyethersulfone, and polyethylene glycol. At least some of the second plurality of channels may include a coating material on the inner surface of the at least some channels. The coating material may be selected from cellulose, polyethersulfone, and polyethylene glycol. At least some of the first plurality of channels may include a first coating material on the inner surface of the at least some channels of the first plurality of channels, and at least some of the second plurality of channels may include a second coating material on the inner surface of the at least some channels of the second plurality of channels.

[0024] Each member of the first plurality of channels may include an opening at the first surface, and each member of the second plurality of channels may include an opening at the interface between the first layer and the second layer, wherein the average cross-sectional area of ​​the openings of the first plurality of channels is different from the average cross-sectional area of ​​the openings of the second plurality of channels. The average cross-sectional area of ​​the openings of the first plurality of channels may be greater than the average cross-sectional area of ​​the openings of the second plurality of channels. The ratio of the total area of ​​the openings of the first plurality of channels at the first surface to the area of ​​the first surface may be greater than the ratio of the total area of ​​the openings of the second plurality of channels at the interface to the area of ​​the interface.

[0025] Each member of the first plurality of channels may have a volume in the first layer, and each member of the second plurality of channels may have a volume in the second layer, and the ratio of the total volume of the first plurality of channels in the first layer to the volume of the first layer may be greater than the ratio of the total volume of the second plurality of channels in the second layer to the volume of the second layer.

[0026] For each of at least some members of the second plurality of channels, the member channel may have an opening having a first cross-sectional area at the interface between the first and second layers and a second cross-sectional area at a location displaced from the interface along the member channel axis, wherein the first cross-sectional area may be smaller than the second cross-sectional area. The ratio of the first cross-sectional area to the second cross-sectional area may be 0.85 or less (e.g., 0.50 or less). Each member of the second plurality of channels may have an orientation defined by the channel axis of the member relative to the first direction, and the full width at half maximum (FWHM) of the orientation distribution of the second plurality of channels may be 20 degrees or less (e.g., 10 degrees or less).

[0027] Unless otherwise expressly stated, implementations of the filter may also include any other features described herein, including any combination of features described individually in different implementations.

[0028] As used herein, the term “about” means “approximately” (e.g., plus or minus 10% of the value referred to).

[0029] The embodiments described by references such as "an embodiment" or "implementation" in this specification may include specific aspects, features, structures, or characteristics, but not every embodiment is required to include such aspect, feature, structure, or characteristic. Furthermore, such phrases may, but are not necessarily, refer to the same embodiments mentioned in other parts of this specification. Moreover, when a specific aspect, feature, structure, or characteristic is described in connection with an embodiment, whether explicitly stated or not, the influence of such aspect, feature, structure, or characteristic or its association with other embodiments is within the knowledge of a person skilled in the art.

[0030] As used herein, the word "a" preceding a noun indicates one or more of the specific noun. For example, the phrase "a mammalian cell" means "one or more mammalian cells".

[0031] The term "tangential flow filter unit" or "TFF unit" is known in the art and refers to a device comprising at least one housing (such as a cylinder) and at least one cross-flow (tangential) filter located within the housing, such that a majority surface of the filter is positioned parallel to the flow of fluid (e.g., cell culture) through the unit. TFF units are well known in the art and are commercially available. The housing may include a first inlet / outlet and a second inlet / outlet, positioned, for example, to allow fluid to pass through the first inlet / outlet, across at least one cross-flow filter, and through the second inlet / outlet. In some examples, the loop system may include, for example, multiple TFF units connected in series and / or in parallel. For example, a loop system comprising two or more TFF units may include fluid conduits fluidly connecting adjacent pairs of TFF units in the system. In other examples, the loop system may include two or more sets of two or more TFF units fluidly connected by fluid conduits. Any TFF unit described herein or known in the art is capable of receiving fluid in a first flow direction and a second flow direction.

[0032] The term "tangential flow virus filter unit" or "TFVF unit" is known in the art and refers to a device comprising at least one housing (such as a cylinder) and at least one cross-flow (tangential) virus filter located within the housing, such that a majority surface of the virus filter is positioned parallel to the flow of fluid (e.g., cell culture) through the unit. The housing may include a first inlet / outlet and a second inlet / outlet, positioned, for example, to allow fluid to pass through the first inlet / outlet, across the at least one cross-flow virus filter, and through the second inlet / outlet. In some examples, the loop system may include, for example, multiple TFVF units connected in series and / or parallel. For example, a loop system comprising two or more TFVF units may include fluid conduits fluidly connecting adjacent pairs of TFVF units in the system. In other examples, the loop system may include two or more sets of two or more TFVF units fluidly connected by fluid conduits. Any TFVF unit described herein or known in the art is capable of receiving fluid in a first flow direction and a second flow direction.

[0033] The terms "cross-flow filter" or "tangential filter" are known in the art and refer to a filter designed such that it can be positioned within a TFF or TFVF unit such that a large portion of the filter's surface is parallel to the flow of a fluid (e.g., a fluid comprising recombinant therapeutic proteins) (e.g., a first flow direction and a second flow direction). For example, a cross-flow filter can have any shape that allows tangential flow filtration, such as a tubular or rectangular shape. Particularly useful cross-flow filters are designed to generate low amounts of fluid turbulence or shear stress in the fluid when a fluid (e.g., cell culture) flows over the surface of the cross-flow filter (e.g., unidirectional to bidirectional flow). Cross-flow filters are commercially available, for example, from Sartorius, MembraPure, Millipore, and Pall Corporation.

[0034] The terms "low-turbulence pump" or "LTP" are known in the art and refer to a device that can move a fluid (e.g., a fluid comprising recombinant therapeutic proteins) within a system or loop in a single direction (e.g., a first flow direction or a second flow direction), or allow a fluid (e.g., a fluid comprising recombinant therapeutic proteins) to flow reversibly within a system in two directions (a first flow direction and a second flow direction) without inducing significant shear stress or fluid turbulence in the fluid (e.g., the fluid comprising recombinant therapeutic proteins). When an LTP is used to move a fluid (e.g., a fluid comprising recombinant therapeutic proteins) in alternating first and second flow directions, the second flow direction is substantially opposite to the direction of the first flow direction. An example of an LTP is a peristaltic pump. Other examples of LTPs are known in the art.

[0035] The term "mammalian cell" means any cell that is derived from or originates from any mammal (e.g., human, hamster, mouse, green monkey, rat, pig, cow, or rabbit). For example, a mammalian cell can be an immortalized cell. In some embodiments, the mammalian cell is a differentiated cell. In some embodiments, the mammalian cell is an undifferentiated cell. Non-limiting examples of mammalian cells are described herein. Further examples of mammalian cells are known in the art.

[0036] The term “substantially free” means that the composition (e.g., liquid culture medium) is at least or about 90% free (e.g., at least or about 95%, 96%, 97%, 98%, or at least or about 99%, or about 100%) of the specified substance (e.g., mammalian cells).

[0037] The term "0.5x volume" means approximately 50% of the volume. The term "0.6x volume" means approximately 60% of the volume. Similarly, 0.7x, 0.8x, 0.9x, and 1.0x respectively mean approximately 70%, 80%, 90%, or 100% of the volume.

[0038] The term "culture" or "cell culture" refers to the maintenance or proliferation of mammalian cells under a set of controlled physical conditions.

[0039] The term "mammalian cell culture" refers to a liquid culture medium containing multiple mammalian cells maintained or proliferated under a set of controlled physical conditions.

[0040] The term "liquid culture medium" refers to a fluid containing sufficient nutrients to allow cells (e.g., mammalian cells) to grow or proliferate in vitro. For example, a liquid culture medium may contain one or more of the following: amino acids (e.g., 20 amino acids), purines (e.g., hypoxanthine), pyrimidines (e.g., thymidine), choline, inositol, thiamine, folic acid, biotin, calcium, nicotinamide, pyridoxine, riboflavin, thymidine, cyanocobalamin, pyruvate, lipoic acid, magnesium, glucose, sodium, potassium, iron, copper, zinc, and sodium bicarbonate. In some embodiments, the liquid culture medium may contain serum from mammals. In some embodiments, the liquid culture medium does not contain serum or other extracts from mammals (limited to liquid culture medium). In some embodiments, the liquid culture medium may contain trace metals, mammalian growth hormones, and / or mammalian growth factors. Another example of a liquid culture medium is a basal culture medium (e.g., a medium containing only inorganic salts, a carbon source, and water). Non-limiting examples of liquid culture media are described herein. Further examples of liquid culture media are known in the art and are commercially available. Liquid culture media can contain mammalian cells at any density. For example, as used herein, a certain volume of liquid culture medium removed from a bioreactor may be substantially free of mammalian cells.

[0041] The term "liquid culture medium without animal-derived components" means a liquid culture medium that does not contain any components (e.g., proteins or serum) derived from mammals.

[0042] The term "serum-free liquid culture medium" refers to a liquid culture medium that does not contain mammalian serum.

[0043] The term "serum-containing liquid culture medium" refers to a liquid culture medium containing mammalian serum.

[0044] The term "chemically defined liquid culture medium" is a term used in the art and refers to a liquid culture medium in which all chemical components are known. For example, chemically defined liquid culture media do not contain fetal bovine serum, bovine serum albumin, or human serum albumin because these formulations typically contain a complex mixture of albumin and lipids.

[0045] The term "protein-free liquid culture medium" refers to a liquid culture medium that does not contain any protein (e.g., any detectable protein).

[0046] The term "stirring" refers to agitating or otherwise moving a portion of a liquid culture medium in a bioreactor. This is performed, for example, to increase the concentration of dissolved O2 in the liquid culture medium within the bioreactor. Stirring can be performed using any method known in the art (e.g., instruments or propellers). Exemplary devices and methods that can be used to stir a portion of a liquid culture medium in a bioreactor are known in the art.

[0047] The term "therapeutic protein drug substance" refers to the following recombinant proteins (e.g., immunoglobulins, protein fragments, engineered proteins, or enzymes) that have been adequately purified or isolated from contaminating proteins, lipids, and nucleic acids (e.g., those present in liquid culture media or derived from host cells (e.g., from mammalian, yeast, or bacterial host cells)) and biological contaminants (e.g., viral and bacterial contaminants), and can be formulated into a drug substance without any further substantial purification and / or decontamination steps.

[0048] The term "integration process" refers to a process performed using structural elements that work collaboratively to achieve a specific result (e.g., generating a therapeutic protein drug substance from a liquid culture medium).

[0049] The term "continuous process" means a process in which a fluid is continuously fed through at least a portion of a system. For example, in any of the exemplary continuous biomanufacturing systems described herein, a liquid culture medium containing a recombinant therapeutic protein is continuously fed into the system during its operation, and the therapeutic protein drug substance is fed out of the system. In another example, a continuous process is a process in which a liquid culture medium containing a recombinant therapeutic protein from a bioreactor is continuously fed through a first MCCS. Another example of a continuous process is a process in which a liquid culture medium containing a recombinant therapeutic protein from a bioreactor is continuously fed through first and second MCCSs. Further examples include a process in which a liquid culture medium containing a recombinant therapeutic protein is continuously fed through a first MCCS, a process in which a liquid culture medium containing a recombinant therapeutic protein is continuously fed through first and second MCCSs, or a process in which a fluid containing a recombinant therapeutic protein is continuously fed through a second MCCS.

[0050] The term "immunoglobulin" refers to a polypeptide of an immunoglobulin protein containing an amino acid sequence (e.g., a variable domain sequence, a frame sequence, or a constant domain sequence) of at least 15 amino acids (e.g., at least 20, 30, 40, 50, 60, 70, 80, 90, or 100 amino acids). Immunoglobulins can be, for example, light chain immunoglobulins comprising at least 15 amino acids, or heavy chain immunoglobulins comprising at least 15 amino acids. Immunoglobulins can be isolated antibodies (e.g., IgG, IgE, IgD, IgA, or IgM). Immunoglobulins can be subclasses of IgG (e.g., IgG1, IgG2, IgG3, or IgG4). Immunoglobulins can be antibody fragments, such as Fab fragments, F(ab')2 fragments, or scFv fragments. Immunoglobulins can also be bispecific or trispecific antibodies, or dimer, trimer, or multimer antibodies, or biantibodies. or Immunoglobulins can also be engineered proteins (e.g., fusion proteins) containing at least one immunoglobulin domain. Non-limiting examples of immunoglobulins are described herein, and further examples of immunoglobulins are known in the art.

[0051] The terms "protein fragment" or "peptide fragment" refer to a portion of a polypeptide sequence having a length of at least or about 4 amino acids, at least or about 5 amino acids, at least or about 6 amino acids, at least or about 7 amino acids, at least or about 8 amino acids, at least or about 9 amino acids, at least or about 10 amino acids, at least or about 11 amino acids, at least or about 12 amino acids, at least or about 13 amino acids, at least or about 14 amino acids, at least or about 15 amino acids, at least or about 16 amino acids, at least or about 17 amino acids, at least or about 18 amino acids, at least or about 19 amino acids, or at least or about 20 amino acids, or a length of more than 20 amino acids. Recombinant protein fragments can be produced using any of the processes described herein.

[0052] The term "engineered protein" refers to a polypeptide that is not naturally encoded by endogenous nucleic acids present in an organism (e.g., mammals). Examples of engineered proteins include enzymes (e.g., those with one or more amino acid substitutions, deletions, insertions, or additions that increase the stability and / or catalytic activity of the engineered enzyme), fusion proteins, antibodies (e.g., bivalent, trivalent, or dual antibodies), and antigen-binding proteins containing at least one recombinant scaffold sequence.

[0053] The term "multi-column chromatography system" or "MCCS" refers to a system having a total of two or more interconnected or switched chromatographic columns and / or chromatographic membranes. A non-limiting example of a multi-column chromatography system is a periodic countercurrent chromatography system (PCC) containing a total of two or more interconnected or switched chromatographic columns and / or chromatographic membranes. Further examples of multi-column chromatography systems are described herein and are known in the art.

[0054] The term "capture" means performing steps to partially purify (e.g., at least or about 5% by weight (e.g., at least or about 10%, 15%, 20%, 25%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or at least or about 95%), concentrate, and stabilize a recombinant therapeutic protein from a liquid culture medium or diluted liquid culture medium (e.g., at least or about 10%, 15%, 20%, 25%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or at least or about 95%), concentrate, and stabilize a recombinant therapeutic protein. Typically, capture is performed using a resin that binds to the recombinant therapeutic protein (e.g., by using affinity chromatography). Non-limiting methods for capturing recombinant therapeutic proteins from liquid culture media or diluted liquid culture media are described herein, and other methods are known in the art. Recombinant therapeutic proteins can be captured from liquid culture media using at least one chromatographic column and / or chromatographic membrane (e.g., any chromatographic column and / or chromatographic membrane described herein).

[0055] The term "purification" refers to the steps performed to separate a recombinant therapeutic protein from one or more other impurities (e.g., major impurities) or components (e.g., proteins in liquid culture media or one or more other components present in or secreted from mammalian cells, such as DNA, RNA, other proteins, endotoxins, viruses, etc.)) present in the fluid containing the recombinant therapeutic protein. For example, purification may be performed during or after the initial capture step. Purification may be performed using resins, membranes, or any other solid support conjugating the recombinant therapeutic protein or contaminants (e.g., by using affinity chromatography, hydrophobic interaction chromatography, anion or cation exchange chromatography, or molecular sieve chromatography). Recombinant therapeutic proteins may be purified from a fluid containing them using at least one chromatographic column and / or chromatographic membrane (e.g., any column or membrane described herein).

[0056] The term "purification" is a term used in the art and refers to the steps performed to remove residual trace or small amounts of contaminants or impurities from a fluid containing a recombinant therapeutic protein close to the final desired purity. Purification can be performed, for example, by passing the fluid containing the recombinant therapeutic protein through one or more chromatographic columns or one or more membrane absorbers that selectively bind the target recombinant therapeutic protein or small amounts of contaminants or impurities present in the fluid. In such an example, the eluent / filtrate from one or more columns or membrane absorbers contains the recombinant therapeutic protein.

[0057] The term "elution / filtrate" is a term used in the art and refers to a fluid released from a chromatographic column or membrane containing a detectable amount of recombinant therapeutic protein.

[0058] The term “filtration” means the removal of at least some (e.g., at least 80%, 90%, 95%, 96%, 97%, 98%, or 99%) of undesirable biological contaminants (e.g., mammalian cells, bacteria, yeast cells, viruses, or mycobacteria) and / or particulate matter (e.g., precipitated proteins) from a liquid (e.g., a liquid culture medium or fluid present in any system or process described herein).

[0059] The terms "secreted protein" or "secreted recombinant protein" refer to a protein (e.g., a recombinant protein) that, upon translation within mammalian cells, initially contains at least one secretion signal sequence and is at least partially secreted into the extracellular space (e.g., liquid culture medium) by enzymatic cleavage of the secretion signal sequence within mammalian cells. Those skilled in the art will understand that a "secreted" protein does not need to be completely dissociated from the cell to be considered a secreted protein.

[0060] The term "perfusion bioreactor" refers to a bioreactor containing multiple cells (e.g., mammalian cells) in a first liquid culture medium, wherein the culture of cells present in the bioreactor involves periodically or continuously removing the first liquid culture medium and simultaneously or shortly thereafter adding a substantially equal volume of a second liquid culture medium to the bioreactor. In some examples, the volume of the first liquid culture medium removed and added varies incrementally over increasing periods during the culture period (e.g., periods of approximately 24 hours, periods between approximately 1 minute and approximately 24 hours, or periods longer than 24 hours) (e.g., increases or decreases) (e.g., the daily refeed rate of the culture medium). The fraction of culture medium removed and replaced daily can vary depending on the specific cells being cultured, the initial inoculation density, and the cell density at a particular time. "RV" or "reactor volume" refers to the volume of culture medium present at the start of the culture process (e.g., the total volume of culture medium present after inoculation).

[0061] The term "feed-batch bioreactor" is a term used in the art and refers to a bioreactor containing multiple cells (e.g., mammalian cells) in a first liquid culture medium, wherein the culture of cells present in the bioreactor involves periodically or continuously adding a second liquid culture medium to the first liquid culture medium without substantially or significantly removing the first or second liquid culture medium from the cell culture. The second liquid culture medium may be the same as the first liquid culture medium. In some examples of fed-batch culture, the second liquid culture medium is a concentrated form of the first liquid culture medium. In some examples of fed-batch culture, the second liquid culture medium is added as a dry powder.

[0062] The term "clarified liquid culture medium" means a liquid culture medium obtained from bacterial or yeast cell cultures that is substantially free of (e.g., at least 80%, 85%, 90%, 92%, 94%, 96%, 98%, or 99% free of) bacteria or yeast cells.

[0063] The term "unit operation" is a term used in the art and refers to a functional step that can be performed in the process of manufacturing a therapeutic protein pharmaceutical substance from a liquid culture medium. For example, an operation unit may be filtration (e.g., removal of contaminating bacteria, yeast, viruses, and / or mycobacteria and / or particulate matter from a fluid containing recombinant therapeutic proteins), capture, removal of epitope tags, purification, retention or storage, refining, virus inactivation, adjustment of the ion concentration and / or pH of the fluid containing recombinant therapeutic proteins, and removal of unwanted salts.

[0064] "Specific productivity" or "SPR" is a term used in the art and, as used herein, refers to the mass or enzyme activity of recombinant therapeutic proteins produced per mammalian cell per day. The SPR of recombinant therapeutic antibodies is typically measured in mass / cell / day. The SPR of recombinant therapeutic enzymes is typically measured in units / cell / day or (units / mass) / cell / day.

[0065] "Volume Productivity" or "VPR" is a term used in the art and, as used herein, refers to the mass or enzyme activity of recombinant therapeutic proteins produced per day per volume of culture (e.g., per L of bioreactor, vessel, or tube volume). The VPR of recombinant therapeutic antibodies is typically measured in mass / L / day. The VPR of recombinant therapeutic enzymes is typically measured in units / L / day or mass / L / day.

[0066] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While methods and materials similar to or equivalent to those described herein may be used in the practice of this method and system, suitable methods and systems are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated herein by reference in their entirety. In case of conflict, this specification, including its definitions, shall prevail. Furthermore, methods and examples are illustrative only and are not intended to be limiting. Attached Figure Description

[0067] Figure 1 is a schematic diagram of an example of a pressure-driven virus filtering subsystem.

[0068] Figure 2 is a schematic diagram of an example of a tangential flow virus filtering subsystem.

[0069] Figure 3 is a schematic diagram of an example of a pressure-driven and pump-driven tangential flow virus filtering subsystem.

[0070] Figure 4 is a schematic diagram of an example of a constant pressure, constant tangential flow virus filtering subsystem.

[0071] Figure 5 is a schematic diagram of an example of a filter component.

[0072] Figure 6 is a schematic cross-sectional view of the filter component.

[0073] Figures 7A to 7E are schematic diagrams of examples of filter components with thickness variations between the first and second surfaces.

[0074] Figure 8A is a schematic cross-sectional view of an example of a filter component.

[0075] Figure 8B is a schematic cross-sectional view of another example of a filter component.

[0076] Figure 8C is a schematic diagram of a portion of the surface of a filter component.

[0077] Figure 9A is a schematic cross-sectional view of an example of a filter component with an inclined channel.

[0078] Figure 9B is a schematic cross-sectional view of another example of a filter component with inclined channels.

[0079] Figure 10 is a schematic cross-sectional view of another example of a filter component.

[0080] Figure 11 is a schematic cross-sectional view of an example filter component having a channel including lateral protrusions.

[0081] Figure 12 is a schematic cross-sectional view of an example of a filter component including channels with coating.

[0082] Figure 13 is a schematic cross-sectional view of an example of a filter component including multiple channels.

[0083] Figure 14 is a schematic diagram of an example of a layered tangential virus filtering unit.

[0084] The same reference numerals indicate the same elements. Detailed Implementation

[0085] introduction

[0086] Biomanufacturing systems hold great promise for the large-scale production of a wide variety of biological products, including therapeutic drugs such as recombinant protein substances. In many such systems, suitable cell cultures are combined in a bioreactor (e.g., a perfusion reactor) with growth media, buffers, and other input reagent streams to generate product substances. Process fluids are extracted from the bioreactor and typically purified via one or more multi-column chromatography purification units to separate the desired product from the process fluid. Aspects of biomanufacturing systems and their related components are described, for example, in PCT Patent Application Publication No. WO2018 / 035116, the entire contents of which are incorporated herein by reference.

[0087] Biomanufacturing systems also typically include a virus filtration stage or subsystem for removing viral particles from process fluids. Virus filtration subsystems can generally be implemented in a variety of different configurations. For example, some biomanufacturing systems include pressure-driven virus filtration subsystems. Figure 1 is a schematic diagram of a pressure-driven virus filtration subsystem 100. Subsystem 100 includes a feed container 102, a delivery conduit 106, and a filter unit 108 with an internal filter membrane 110. During operation of subsystem 100, fluid 104 (such as process fluid extracted from a bioreactor or from another component of a biomanufacturing system downstream of the bioreactor) is continuously or batch-wise introduced into feed container 102. Feed container 102 is pressurized such that the gas pressure within feed container 102 is significantly greater than atmospheric pressure, thereby creating a pressure gradient relative to the subsystem outlet, which drives fluid 104 out of feed container 102 through conduit 106 and into filter unit 108. Once within filter unit 108, fluid 104 passes through filter element 110, which filters out viral particles.

[0088] The flow of fluid 104 in subsystem 100 is entirely pressure-driven, with a single parameter (feed container gas pressure) determining the flux through filter unit 108. Pressure drops occur only across filter member 110 because the gas pressure downstream of filter member 110, which contains product stream 112, is essentially atmospheric pressure. Product stream 112 corresponds to fluid 104 after the removal of virus particles.

[0089] It should be noted that in subsystem 100, viral particles or other process impurities (such as host cell proteins, microscopically visible particles, or the protein products themselves) accumulate in filter element 110. Therefore, the lifespan of filter element 110 is limited by the time elapsed before viral penetration or filter clogging occurs, and viral particles in fluid 104 upstream of filter element 110 are not completely captured by filter element 110 (i.e., a certain number of particles pass through filter element 110 and appear in product stream 112). Therefore, while subsystem 100 can be implemented with a fairly simple configuration and provides effective filtration of viral particles, filter element 110 may be prone to fouling during operation, which may limit the effectiveness of this type of viral filtration and increase its cost. Due to the relatively short operating window before changes to filter element 110, subsystem 100 may be more suitable for batch operation compared to continuous viral filtration operations as part of a continuous biomanufacturing process.

[0090] Figure 2 is a schematic diagram of a tangential flow filtration subsystem 200. Subsystem 200 includes a feed container 202 that retains fluid 220 (e.g., a process fluid containing one or more products from a bioreactor). Subsystem 200 is pump-driven and includes a pump 206. During operation, pump 206 drives fluid 220 from feed container 202 through conduits 204 and 208 and into filter unit 210, which includes filter member 212. For example, filter member 212 is typically a planar membrane and is oriented substantially tangentially to the flow direction of fluid 220 within filter unit 210. Specifically, within filter unit 210, fluid 220 flows from inlet 224 to outlet 226 in a direction substantially along the length of filter unit 210 (as indicated by arrow 228). As the fluid actively flows in direction 228, a portion of the fluid moves tangentially through member 212 in the direction of outlet 230. The tangentially moving fluid is filtered by component 212 to remove virus particles, so that the product stream 222 exiting from outlet 230 is free of virus particles. Fluid 220 that does not move through filter component 212 exits filter unit 210 as residue through outlet 226 and is recirculated back into feed container 202 via conduits 214 and 218. Flow control device 216 can be used to regulate residue pressure.

[0091] In practice, two process variables control the generation rate of the filtered product stream in subsystem 200: the flow rate of fluid 220 controlled by pump 206; and the residual pressure controlled by flow control device 216. Pressure drops occur at multiple locations in subsystem 200 (i.e., between inlet 224 and outlets 230 and 226, and between outlet 226 and feed container 202).

[0092] Compared to conventional "dead-end" filtration systems (such as those shown in Figure 1), tangential flow virus filtration (TFVF) subsystems offer several advantages. In TFVF, the flux of fluid 220 on component 212 is maintained via a "sweeping" flow motion, which can result in a higher per-unit-area filter membrane throughput. Therefore, TFVF subsystems are better suited for implementation in continuous biomanufacturing systems because they can accommodate continuous inflow of process fluids from the bioreactor and continuous effluent of the resulting product stream for further purification and / or analysis. TFVF subsystems can also be implemented in batch biomanufacturing systems to increase the lifespan of the viral filter membrane due to the relatively low amount of filter fouling caused by the tangential operating mode. Limitations on TFVF subsystems may sometimes include a generally narrower set of available filter components and the use of a recirculation pump, which may impose certain operational constraints on the subsystem.

[0093] It is possible to implement a pressure-driven and pump-driven TFVF subsystem. Figure 3 is a schematic diagram of such a subsystem 300, which includes a feed container 302, a filter unit 304, and a recirculation pump 306. These components function in a manner similar to the corresponding components in Figure 2 above. During operation, the feed container 302 is pressurized by delivering air or another gas via inlet 312. Fluid 308 flows from the feed container 302 to the filter unit 304, which includes tangentially oriented filter elements 314. As the fluid 308 flows over the elements 314, a portion of the fluid moves through the membrane 314, which removes viral particles from the fluid, such that the product stream 310 emerging from the filter unit 304 is free of viral particles. Fluid that has not diffused through the filter elements 314 emerges from the filter unit 304 as effluent and is recirculated back to the feed container 302 by the pump 306. Therefore, in subsystem 300, both the pressurized feed container 302 and the pump 306 drive the fluid 308 to circulate through the subsystem.

[0094] As described above, two operating parameters can be adjusted to control the circulation of fluid 308 through subsystem 300: the recirculation flow rate (determined by pump 306) and the system fluid pressure (pressurized via feed container 302). One advantage of subsystem 300 is that the fluid pressure is effectively kept constant in the recirculation portion of the subsystem. That is, the fluid pressure at the inlet of filter member 314 in feed container 302 and the fluid pressure of the residue emerging from filter member 314 are approximately the same. In subsystem 300, a significant pressure drop occurs only across filter member 314. Therefore, the rate at which the product stream emerges from filter member 314 is controlled relatively directly.

[0095] Subsystem 300 is an example of a constant pressure system. By appropriately adjusting pump 306, subsystem 300 can also operate at a constant tangential flow rate, thereby ensuring that a continuous product stream 310 emerges from filter unit 304 at a constant rate. Constant pressure, constant tangential flow filtration subsystems can also be implemented in different ways. Figure 4 is a schematic diagram showing another example of filtration subsystem 400, which includes a feed container 402, a conduit 404 connecting the feed container 402 and filter unit 406, a conduit 408 connecting the filter unit 406 and pump 410, and a conduit 412 connecting pump 410 and inlet 414 of feed container 402.

[0096] During operation of subsystem 400, air or another gas is delivered to feed container 402 through inlet 424, pressurizing the interior of the feed container. The fluid pressure within feed container 402 drives fluid 426 (e.g., process fluid from an intermediate purification stage of a bioreactor or biomanufacturing system) present in the feed container out of the feed container through conduit 404 and into filter unit 406. Filter unit 406 includes filter elements (not shown in FIG. 4) oriented such that fluid 426 within filter unit 406 flows in a direction tangential (or substantially tangential) to the surface of the filter elements. A portion of fluid 426 moves through the filter elements and exits filter unit 406 as product stream 428 through outlet 430, having little or no viral load. The remaining fluid 426 exits filter unit 406 as residue through outlet 432 and is circulated via conduits 408 and 412 through pump 410. Pump 410 drives the residue back into feed container 402 through inlet 414. Therefore, subsystem 400 is capable of continuously filtering fluid 426, wherein a portion of fluid 426 is removed from the subsystem as filtered product stream 428, and the remaining fluid 426 is recycled for another pass through filter unit 406. Additional fluid 426 may be introduced into subsystem 400 before or during operation via conduit 416 and check valve 418; additional fluid 426 is introduced into feed container 402 through inlet 420.

[0097] The structure of filter unit 406 and the filter element therein differ from the corresponding filter unit in FIG. 3. In FIG. 4, filter unit 406 includes a filter element based on hollow fibers. FIG. 5 is a schematic cross-sectional view showing an example of filter element 406. Filter unit 406 includes filter body 502, filter element 504, and outlet 430. Conduits 404 and 408 are connected to an internal channel within filter body 502. As is apparent from FIG. 5, filter body 502 is formed of hollow fibers, wherein orifices are formed in the sidewalls of the fibers. Filter element 504 contacts the sidewalls of the fibers and effectively has a tubular structure. Fluid 426 enters filter body 502 and flows in the direction indicated by the arrow in FIG. 5. A portion of fluid 426 passes through filter element 504 and exits from outlet 430 as a product stream. The remaining fluid 426 enters conduit 408 as residue and is recirculated by a pump (e.g., pump 410).

[0098] In dead-end filter units (as shown, for example, in Figure 1), the fluid pressure within the filter unit (which drives fluid flow through the filter) also presses solid material against the front surface of the filter, resulting in a reduced throughput due to the reduced open volume within the filter element. For fluids with significant suspended solids, fouling of the filter element can occur relatively quickly.

[0099] Filter unit 406 has many advantages compared to such dead-end filter units. Because fluid 426 flows in a tangential direction relative to the sidewalls of filter body 502 and filter member 504, the cross-flow of fluid 426 helps to "sweep" solid particles from the surface of filter member 504, which helps to reduce the scaling rate on the surface of filter member.

[0100] Furthermore, both the flow rate of fluid 426 on the surface of filter element 504 (referred to as the "cross-flow rate") and the fluid pressure within filter element 504 can be adjusted accordingly by adjusting the pressure within pump 410 and feed container 402. As fluid 426 flows through filter element 504 and filter body 502, a transmembrane pressure (TMP) is applied across the thickness of filter element 504. TMP can be adjusted by changing the cross-flow rate (e.g., via pump 410) and / or by changing the fluid pressure in container 402. The TMP pressure drives a portion of fluid 426 through filter element 504, filtering viral particles from the fluid and generating product stream 428. Due to the cross-flow scavenging effect of fluid 426 and the adjustability of the cross-flow rate and TMP, filter unit 406 can typically operate for a significantly longer period of time before scaling occurs and replacement is required, compared to comparable dead-end filter units.

[0101] Typically, virus filter elements are not used in tangential flow filtration systems, but rather in dead-end filtration systems (such as those shown in Figure 1). For virus filtration in dead-end systems, virus filter elements are typically relatively thin to ensure high flow rates (e.g., high throughput) of fluid through the filter element. As discussed above, such virus filter elements tend to scale relatively quickly and are therefore not well-suited for continuous filtration operations over periods of days or weeks.

[0102] Continuous virus filtration

[0103] To continuously filter process fluids extracted directly from bioreactors or intermediate purification stages of biomanufacturing systems, the inventors have implemented a tangential flow virus filtration subsystem, as shown in Figures 4 and 5. Furthermore, the inventors have discovered that such a subsystem (and particularly the virus filter components) can be configured in various ways to reduce the rate of fouling on the filter components, thereby allowing for extended periods of continuous operation.

[0104] In some implementations, the tangential flow virus filtration subsystem is configured such that the lateral fluid pressure (i.e., transmembrane pressure) applied to the filter element is between 0 psi and 50 psi (e.g., between 0 psi and 45 psi, between 0 psi and 40 psi, between 0 psi and 35 psi, between 0 psi and 30 psi, between 0 psi and 25 psi, between 0 psi and 20 psi, between 0 psi and 15 psi, between 0 psi and 10 psi, between 5 psi and 50 psi, between 5 psi and 40 psi). (Any pressure range between 5 psi and 30 psi, between 5 psi and 20 psi, between 10 psi and 50 psi, between 10 psi and 40 psi, between 10 psi and 30 psi, between 10 psi and 20 psi, between 15 psi and 50 psi, between 15 psi and 40 psi, between 15 psi and 30 psi, between 20 psi and 50 psi, between 20 psi and 40 psi, between 25 psi and 50 psi, or any pressure range between 0 psi and 50 psi). In some implementations, the lateral fluid pressure applied to the filter element is 50 psi or less (e.g., 45 psi or less, 40 psi or less, 35 psi or less, 30 psi or less, 25 psi or less, 20 psi or less, 15 psi or less, 10 psi or less, 5 psi or less, 4 psi or less, 3 psi or less, 2 psi or less, 1 psi or less, 0.5 psi or less, 0.25 psi or less, or even less).

[0105] Generally, by selecting a lower lateral fluid pressure, the flux on the filter element is reduced, which decreases the rate of product flow generation. However, the inventors have observed that a lower lateral fluid pressure increases the lifespan of the virus filter element by increasing the time elapsed before the virus penetrates the outer surface of the filter element.

[0106] Figure 6 is a schematic cross-sectional view of a virus filter component 602. The filter component 602 includes a first surface 604 and a second surface 606. A plurality of channels 612 extend from the first surface 604 through the filter component to the second surface 606. Fluid 608, including virus particles 610, encounters the first surface 604 of the filter component and flows from the first surface 604 through the channels 612 to the second surface 606. As the fluid 608 flows through the channels 612, the virus particles 610 are adsorbed onto the channel walls and retained there, such that the product stream emerging from the second surface 606 is substantially free of virus particles before fouling occurs on the filter element.

[0107] Without being bound by theory, it is believed that once virus particles are within channel 612, fluid transport carries them toward the second surface 606. Furthermore, even adsorbed virus particles can be desorbed and propagated toward the second surface 606 via Brownian motion or fluid transport. By reducing the lateral fluid pressure applied to the filter element, the fluid velocity through the membrane is reduced, thereby decreasing the rate at which virus particles are transported toward the second surface 606 and extending the lifespan of the filter element before viral penetration at the second surface.

[0108] In some implementations, the thickness of the filter element (shown as “d” between the first and second surfaces of the filter element in Figure 6) is significantly greater than the thickness of a standard tangential filter membrane. For example, the thickness of a conventional filter membrane used for tangential filtration operations ranges from about 20 micrometers to 140 micrometers. The filter element 602 used in the tangential viral filtration subsystem described herein can have a thickness d of 150 micrometers or greater (e.g., 160 micrometers or greater, 170 micrometers or greater, 180 micrometers or greater, 190 micrometers or greater, 200 micrometers or greater, 220 micrometers or greater, 240 micrometers or greater, 260 micrometers or greater, 280 micrometers or greater, 300 micrometers or greater, 320 micrometers or greater, 340 micrometers or greater, 350 micrometers or greater, 370 micrometers or greater, 400 micrometers or greater, 450 micrometers or greater, or even greater).

[0109] In some implementations, the thickness of the filter component between the first surface and the second surface is varied. For example, the minimum thickness of the filter component between the surfaces may be 50 micrometers or greater (e.g., 60 micrometers or greater, 70 micrometers or greater, 80 micrometers or greater, 90 micrometers or greater, 100 micrometers or greater, 110 micrometers or greater, 120 micrometers or greater, 130 micrometers or greater, 140 micrometers or greater, 150 micrometers or greater, 160 micrometers or greater, 170 micrometers or greater, 180 micrometers or greater, 190 micrometers or greater, 200 micrometers or greater), and the maximum thickness of the filter component between the surfaces may be 1000 micrometers or less (e.g., 900 micrometers or less, 800 micrometers or less, 700 micrometers or less, 600 micrometers or less, 500 micrometers or less, 475 micrometers or less, 450 micrometers or less, 425 micrometers or less, 400 micrometers or less, 375 micrometers or less, 350 micrometers or less, 325 micrometers or less, 300 micrometers or less, or even less).

[0110] The thickness of the filter component between the first and second surfaces can vary randomly or regularly. Figures 7A to 7E are schematic diagrams illustrating examples of filter components 602 with varying thicknesses between the first surface 604 and the second surface 606. In Figure 7A, the thickness of the filter component varies irregularly along the length of the component. In Figure 7B, the thickness of the filter component varies regularly, where the second surface 606 has a wavy, oscillating, or sinusoidal pattern of peaks and valleys. In Figure 7C, the thickness of the filter component varies regularly, where the second surface has a sawtooth shape, forming a pattern of peaks and valleys, and the thickness of the component varies linearly between the peaks and valleys. In Figure 7D, the thickness of the filter component varies monotonically along the length of the component. The thickness can vary linearly or non-linearly along the length of the component. In Figure 7E, the thickness of the filter component varies in a stepped manner.

[0111] Generally, during tangential virus filtration operations, the flow rate of the fluid passing through the filter element is selected to ensure that the product flow rate is high enough to maintain continuous manufacturing operations, while being low enough to ensure that virus particles do not penetrate the filter element and appear in the product stream. For example, the flow rate can be at least 0.5 L / m² per unit area of ​​the filter element. 2 / hr. (For example, at least 1.0L / m 2 / hr, at least 2.0L / m 2 / hr, at least 5.0L / m 2 / hr, at least 10.0L / m 2 / hr, at least 15.0L / m 2 / hr, at least 20.0L / m 2 / hr, at least 30.0L / m 2 / hr, at least 40.0L / m 2 / hr. The flow rate can also (or alternatively) be 100 L / m³. 2 / hr or less (e.g., 90L / m) 2 / hr or less, 80L / m 2 / hr or less, 70L / m 2 / hr or less, 60L / m 2 / hr or less).

[0112] The overall porosity of the filter element is generally selected to balance the flow rate of fluid passing through the element, the element's ability to retain viral particles, and the element's mechanical strength. In some embodiments, the porosity of the filter element (i.e., the pore volume fraction of the filter element) is 0.05 or greater (e.g., 0.10 or greater, 0.15 or greater, 0.20 or greater, 0.25 or greater, 0.30 or greater, 0.35 or greater, 0.40 or greater, 0.45 or greater, 0.50 or greater, 0.55 or greater, 0.60 or greater, or even greater). In some embodiments, the porosity of the filter element is 0.90 or less (e.g., 0.88 or less, 0.86 or less, 0.84 or less, 0.82 or less, 0.80 or less, 0.78 or less, 0.76 or less, 0.74 or less, 0.72 or less, 0.70 or less, or even less). The porosity of the filter components can be, for example, between 0.30 and 0.90, or any smaller range within this range.

[0113] In some implementations, the thickness of the filter element may be smaller relative to the lateral dimension of the filter element. For example, the filter element may have a maximum lateral dimension when extended in a plane, and the ratio of the maximum lateral dimension of the filter element to the thickness of the filter element may be 5 or greater (e.g., 10 or greater, 15 or greater, 20 or greater, 30 or greater, 40 or greater, 50 or greater, 75 or greater, 100 or greater).

[0114] Filter components can generally be formed from a wide variety of materials. Examples of suitable materials include, but are not limited to, polyvinylidene fluoride (PVDF), hydrophilic PVDF, regenerated cellulose, and other materials used to construct chemically synthesized membranes. The filter components described herein can be manufactured using and / or modified from filter manufacturing methods generally known in the art.

[0115] Channel architecture

[0116] A filter element includes pores or channels extending between a first and a second surface of the element, allowing fluid to pass through the filter element. Simultaneously, viral particles are trapped within the pores (e.g., by adsorption) and thereby prevented from appearing in the product stream. The following discussion will refer to "channels" in the filter element, but it should be understood that the term "pore" can also be used to describe the same feature.

[0117] Figure 8A is a schematic cross-sectional view of a filter member 602 including channel 802. The number density of channels per unit on the first surface 604 of the filter member 602 can be, for example, 100 / cm². 2 With 10,000 / cm 2Between. That is, the number density of channels can be 100 / cm². 2 Or larger (e.g., 200 / cm) 2 Or larger, 300 / cm 2 Or larger, 400 / cm 2 Or larger, 500 / cm 2 Or larger, 600 / cm 2 Or larger, 700 / cm 2 Or larger, 800 / cm 2 Or larger, 900 / cm 2 Or larger, 1000 / cm 2 Or larger, 1500 / cm 2 Or larger, 2000 / cm 2 Or larger, 2500 / cm 2 Or larger, 3000 / cm 2 Or larger, 3500 / cm 2 Or larger, 4000 / cm 2 Or larger, 4500 / cm 2 (or larger, or even larger). The number density of channels can be 10,000 / cm². 2 Or smaller (e.g., 9500 / cm) 2 Or smaller, 9000 / cm 2 or smaller, 8500 / cm 2 Or smaller, 8000 / cm 2 Or smaller, 7500 / cm 2 Or smaller, 7000 / cm 2 Or smaller, 6500 / cm 2 Or smaller, 6000 / cm 2 Or smaller, 5500 / cm 2 Or smaller, or even smaller).

[0118] In some embodiments, the opening sizes of one or more channels formed in the filter member 602 on the first surface 604 and the second surface 606 are substantially the same (i.e., the cross-sectional areas of the openings on the surfaces are the same within 10%). However, in some embodiments, the opening sizes are different. In particular, the filter member 602 can be manufactured such that, for individual channels, the cross-sectional area of ​​the channel opening in the first surface 604 is larger than the cross-sectional area of ​​the channel opening in the second surface, such that the effective diameter of the channel narrows through the body of the filter member. It has been found that by using such tapered channels, the penetration of viral particles at the second surface 606 is prevented. Without being bound by theory, it is believed that this is due to the smaller channel openings and also due to the reduced flow rate of the fluid through the channels.

[0119] Figure 8B is a schematic diagram of a filter member 602 including multiple tapered channels 808 (only one channel is shown in Figure 8B for clarity). The opening 806 of the channel 804 at the first surface 604 of the filter member has a larger cross-sectional area than the opening of the channel 804 at the second surface 606 of the filter member. The cross-sectional area A1 of the opening 806 can typically be 0.1 μm. 2 With 10μm 2 Between. For example, the cross-sectional area could be 0.1 μm. 2 Or larger (e.g., 0.2 μm) 2 or larger, 0.3μm 2 or larger, 0.4μm 2 or larger, 0.5μm 2 Or larger, 0.6μm 2 Or larger, 0.7μm 2 or larger, 0.8μm 2 Or larger, 0.9μm 2 or larger, 1.0μm 2 or larger, 2.0μm 2 Or larger, 3.0μm 2 or larger, 4.0μm 2 or larger, 5.0μm 2 (or larger, or even larger). Alternatively or additionally, the cross-sectional area may be 10 μm. 2 Or smaller (e.g., 9.5 μm) 2 or smaller, 9.0μm 2 or smaller, 8.5μm 2 or smaller, 8.0μm 2 or smaller, 7.5μm 2 or smaller, 7.0μm 2 or smaller, 6.5μm 2 or smaller, 6.0μm 2 Or smaller, or even smaller).

[0120] The cross-sectional area of ​​the opening 808 of channel 804 is A2. Generally, the ratio A2 / A1 can be 1.0 or less (e.g., 0.95 or less, 0.90 or less, 0.85 or less, 0.80 or less, 0.75 or less, 0.70 or less, 0.65 or less, 0.60 or less, 0.55 or less, 0.50 or less, 0.45 or less, 0.40 or less, 0.35 or less, 0.30 or less, or even less). Among the multiple channels in filter member 602, any channel can have the cross-sectional areas A1 and A2 as discussed above. Furthermore, within a single filter member, the cross-sectional areas A1 and / or A2 of multiple channels can be the same, or the cross-sectional areas A1 and / or A2 can be different.

[0121] For a filter component 602 having multiple channels 804, the channels can have a distribution of cross-sectional area A1. The average value of the distribution of cross-sectional area A1 can be 0.1 μm. 2 With 10μm 2 Between. For example, the average cross-sectional area could be 0.1 μm. 2 Or larger (e.g., 0.2 μm) 2 or larger, 0.3μm 2 or larger, 0.4μm 2 or larger, 0.5μm 2 Or larger, 0.6μm 2 Or larger, 0.7μm 2 or larger, 0.8μm 2 Or larger, 0.9μm 2 or larger, 1.0μm 2 or larger, 2.0μm 2 Or larger, 3.0μm 2 or larger, 4.0μm 2 or larger, 5.0μm 2 (or larger, or even larger). Alternatively or additionally, the average cross-sectional area may be 10 μm. 2 Or smaller (e.g., 9.5 μm) 2 or smaller, 9.0μm 2 or smaller, 8.5μm 2 or smaller, 8.0μm 2 or smaller, 7.5μm 2 or smaller, 7.0μm 2 or smaller, 6.5μm 2 or smaller, 6.0μm 2 Or smaller, or even smaller).

[0122] The full width at half maximum (FWHM) of the cross-sectional area A1 distribution can be as low as 0.05 μm. 2 With 5.0μm 2 Between. For example, the FWHM value of the distribution could be 0.05 μm. 2 or larger (0.1μm) 2 or larger, 0.2μm 2 or larger, 0.3μm 2 or larger, 0.5μm 2 or larger, 1.0μm 2 or larger, 2.0μm 2 (or larger, or even larger) and / or 5.0 μm 2 Or smaller (e.g., 4.5 μm) 2 or smaller, 4.0μm 2or smaller, 3.5μm 2 or smaller, 3.0μm 2 Or smaller, or even smaller).

[0123] Each channel 804 in the first surface 604 has an opening 806 with a minimum opening size corresponding to the shortest distance across the opening and through the centroid of the opening. For each opening 806, the minimum opening size may be 20 nm or larger (e.g., 25 nm or larger, 30 nm or larger, 35 nm or larger, 40 nm or larger, 45 nm or larger, 50 nm or larger, 60 nm or larger, 70 nm or larger, 80 nm or larger, 90 nm or larger, 100 nm or larger, 120 nm or larger, 140 nm or larger, 160 nm or larger, 180 nm or larger, 200 nm or larger, 250 nm or larger, or even larger). For each opening 806, the minimum opening size can be 1 micrometer or smaller (e.g., 900nm or smaller, 850nm or smaller, 800nm ​​or smaller, 750nm or smaller, 700nm or smaller, 650nm or smaller, 600nm or smaller, 550nm or smaller, 500nm or smaller, 450nm or smaller, 400nm or smaller, or even smaller).

[0124] The distribution of the minimum aperture size between apertures 806 can have a full width at half maximum (FWHM) value of 500 nm or less (e.g., 450 nm or less, 400 nm or less, 350 nm or less, 300 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, 75 nm or less, 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, 10 nm or less, or even less).

[0125] Generally, the opening 808 of each channel 804 in the second surface 606 has a minimum opening size corresponding to the shortest distance across the opening and through the centroid of the opening. For each opening 808, the minimum opening size can be within any of the limitations and ranges described above in conjunction with the opening 806. Similarly, the distribution of the minimum opening sizes among the openings 808 can have a full width at half maximum (FWHM) value within any of the limitations or ranges described above in conjunction with the opening 806.

[0126] In some embodiments, the openings 806 of the channels 804 in the filter member 602 are irregularly distributed on the first surface 604 of the filter member 602. In some embodiments, the openings 806 are distributed in a more regular manner. For example, the openings 806 may be distributed according to a regular pattern and may form a rectangular array, a hexagonal array, or any other type of array pattern on the first surface 604. In some embodiments, the average spacing between the centroids of the openings 806 in the first surface 604 is between 20 nm and 5 micrometers (e.g., between 30 nm and 5 micrometers, between 40 nm and 5 micrometers, between 50 nm and 5 micrometers, between 75 nm and 5 micrometers, between 100 nm and 5 micrometers, between 50 nm and 4 micrometers, between 50 nm and 3 micrometers, between 50 nm and 2 micrometers, between 100 nm and 4 micrometers, between 100 nm and 3 micrometers, between 100 nm and 2 micrometers, between 250 nm and 4 micrometers, between 250 nm and 3 micrometers, between 250 nm and 2 micrometers, between 250 nm and 1 micrometer, between 500 nm and 4 micrometers, between 500 nm and 3 micrometers, between 500 nm and 2 micrometers, between 1 micron and 4 micrometers, between 1 micron and 3 micrometers, or any other range within the foregoing range).

[0127] Figure 8C is a schematic diagram showing a portion of a first surface 604, which includes openings 806 for forming a plurality of channels 804 in a filter member. The openings 806 are clustered in a plurality of groups 820, each group being indicated by a dashed line surrounding the members of that group. For the first surface 604 having a plurality of openings 806, each opening has a minimum opening size corresponding to the shortest distance across the opening and through the centroid of the opening. For the plurality of openings 806 in the first surface 604, there exists an average minimum opening size.

[0128] Generally, an opening 806 is considered part of a group if the distance between the centroid of an opening and the centroid of another opening in the group is less than twice the average minimum opening size of the first surface 604. For a group 820 of openings 806 in the first surface 604, the center of each group can be defined as the point representing the shortest sum of distances to the centroids of each opening in the group. Between groups 820, the average center-to-center spacing between nearest neighbor groups can be 2.5 times or more (e.g., 3.0 times or more, 3.5 times or more, 4.0 times or more, 4.5 times or more, 5.0 times or more, 5.5 times or more, 6.0 times or more, 7.0 times or more, 8.0 times or more, 8.5 times or more, 9.0 times or more, 10.0 times or more, 12.0 times or more, 15.0 times or more, or even more).

[0129] In some implementations, for example, as shown in Figure 8B, one or more channels 804 are oriented such that the axis of the channel 804 is oriented generally parallel to the direction of fluid flow through the filter member 602. However, it has been found that by oriented at least some channels 804 such that their respective channel axes are inclined relative to the overall direction of fluid flow through the filter member 602, the fouling rate of the filter member can be significantly reduced, and thus the elapsed time before the filter member reaches its replacement date can be significantly extended. Without being bound by theory, it is believed that by inclining the channel axes relative to the overall direction of fluid flow, the capture of viral particles is enhanced due to increased interaction with viral particles along the channel length.

[0130] Figure 9A is a schematic diagram of a filter member 602 with inclined channels. In Figure 9A, the crossflow direction (i.e., within the filter unit) is indicated by arrow 902, and the direction of the overall fluid flow within the filter member 602 (tangential to the crossflow direction 902) is indicated by arrow 904. The direction of the overall fluid flow is nominally orthogonal to the first surface 604 and the second surface 606 of the filter member 602.

[0131] A channel 906 is formed in the filter member 602, and openings 910 and 912 are correspondingly provided in surfaces 604 and 606. A channel axis 908 extends between the centroids of openings 910 and 912. The channel axis 908 is inclined at an angle α relative to the direction of the overall fluid flow 904.

[0132] In some embodiments, the fraction of channels within filter member 602 that are inclined relative to the direction of overall fluid flow is 20% or more (e.g., 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, 97% or more, 98% or more, 99% or more, or even 100%). For a given channel 906, the angle α can be 5 degrees or greater (e.g., 10 degrees or greater, 15 degrees or greater, 20 degrees or greater, 25 degrees or greater, 30 degrees or greater, 35 degrees or greater, 40 degrees or greater, 45 degrees or greater, 50 degrees or greater, or even greater). Alternatively or additionally, angle α can be 90 degrees or less (e.g., 89 degrees or less, 88 degrees or less, 87 degrees or less, 86 degrees or less, 85 degrees or less, 80 degrees or less, 75 degrees or less, 70 degrees or less, 65 degrees or less, 60 degrees or less, or even less). Angle α can be between 1 degree and 90 degrees (or any smaller range within this range).

[0133] In some embodiments, the average value of the inclination angle α between the channels 906 within the filter assembly and relative to the direction of the overall fluid flow 904 is 5 degrees or greater (e.g., 10 degrees or greater, 15 degrees or greater, 20 degrees or greater, 25 degrees or greater, 30 degrees or greater, 35 degrees or greater, 40 degrees or greater, 45 degrees or greater, 50 degrees or greater, or even greater). Alternatively or additionally, the angle α may be 90 degrees or less (e.g., 89 degrees or less, 88 degrees or less, 87 degrees or less, 86 degrees or less, 85 degrees or less, 80 degrees or less, 75 degrees or less, 70 degrees or less, 65 degrees or less, 60 degrees or less, or even less). The angle α may be between 1 degree and 90 degrees (or any smaller range within this range).

[0134] In some embodiments, for a channel 906 that is inclined relative to the direction of the overall fluid flow 904, the full width at half maximum (FWHM) of the distribution of angle α can be between 0 degrees and 60 degrees. For example, the FWHM of the distribution can be 60 degrees or less (e.g., 50 degrees or less, 40 degrees or less, 30 degrees or less, 20 degrees or less, 15 degrees or less, 10 degrees or less, 5 degrees or less).

[0135] In Figure 9A, channel 906 is inclined toward the crossflow direction 902. However, in some embodiments, one or more channels formed in the filter member 602 may be inclined away from the crossflow direction 902 (i.e., counterclockwise in Figure 9A) relative to the overall fluid flow direction 904. Figure 9B is a schematic diagram showing the filter member 602 with channels 906 inclined away from the crossflow direction 902. The angle between the overall fluid flow direction 904 and the channel axis 908 is α. The various features discussed above in conjunction with Figure 9A are applied in a similar manner to channel 906 in Figure 9B.

[0136] In some embodiments, the fraction of channels in filter member 602 that are inclined away from the crossflow direction is 20% or more (e.g., 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, 97% or more, 98% or more, 99% or more, or even more). It has been found that, in some embodiments, orienting filter member 602 such that some or all of the channels are inclined away from the crossflow direction can further increase the lifespan of the filter member by reducing the rate at which viral particles desorb from internal binding sites within the channels and penetrate the second surface 606 of the filter member.

[0137] It should be noted that in Figure 9A, channel 906 does not undulate or meander through filter member 602. However, in some embodiments, channels in the filter member may extend in multiple directions relative to the direction of overall fluid flow (e.g., by undulation). However, the foregoing considerations also apply to channels in which the channel axis and inclination are defined in the same manner.

[0138] In some implementations, for a particular channel having a channel axis that is inclined or parallel to the overall fluid flow direction, the channel may be partially shielded or blocked at or near the channel opening. Figure 10 is a schematic diagram of a filter component 602 including channel 1006. Channel 1006 has a maximum cross-sectional dimension w as shown. However, at opening 1010, the maximum cross-sectional dimension is w0, which is smaller than w. Generally, w can be selected as needed. o The ratio w0 / w is used to create the shielded channel 1006. In some embodiments, for example, the ratio w0 / w is 0.98 or less (e.g., 0.97 or less, 0.96 or less, 0.95 or less, 0.94 or less, 0.93 or less, 0.92 or less, 0.91 or less, 0.90 or less, 0.85 or less, 0.80 or less, 0.75 or less, 0.70 or less, 0.65 or less, 0.60 or less, 0.55 or less, 0.50 or less, 0.45 or less, 0.40 or less, 0.35 or less, 0.30 or less, 0.25 or less, 0.20 or less, or even less).

[0139] In some embodiments, the shading of the channel opening in the first surface 604 is measured relative to a position directly below the first surface 604. For example, referring again to FIG10, w n It is the maximum cross-sectional dimension of channel 1006 at a location representing 10% of the distance between the first surface 604 and the second surface 606. For partially obscured channel 1006, w n It can be greater than w0. In some implementations, for example, the ratio w0 / w n 0.99 or less (e.g., 0.97 or less, 0.96 or less, 0.95 or less, 0.94 or less, 0.93 or less, 0.92 or less, 0.91 or less, 0.90 or less, 0.85 or less, 0.80 or less, 0.75 or less, 0.70 or less, 0.65 or less, 0.60 or less, 0.55 or less, 0.50 or less, 0.45 or less, 0.40 or less, 0.35 or less, 0.30 or less, 0.25 or less, 0.20 or less, or even less).

[0140] To improve viral particle retention, the inner surface of the channel can be configured to increase its surface area, thereby providing adsorption sites for viral particles. It has been found that the ratio of the average cross-sectional area of ​​the openings to the average surface area of ​​the inner surface of the channel can be a significant factor in reducing the likelihood of viral penetration at the second surface 606, thereby extending the lifespan of the filter member 602. In some embodiments, for example, the ratio of the average cross-sectional area of ​​the channel openings in the first surface 604 to the average surface area of ​​the inner surface of the channel can be 0.05 or less (e.g., 0.04 or less, 0.03 or less, 0.02 or less, 0.01 or less, 0.005 or less, 0.003 or less, 0.001 or less, 0.0005 or less, 0.0001 or less, 0.00001 or less, 0.000001 or less, 0.000001 or less, or even less).

[0141] In some embodiments, to further increase the surface area of ​​the inner surfaces of the channels, some or all of the channels may include lateral protrusions. Figure 11 is a schematic diagram of a filter member 602 including a channel 1102 having openings 1104 and 1106 correspondingly at a first surface 604 and a second surface 606, and five lateral protrusions 1108. The channel 1102 has a channel axis 1110 connecting the centroids of the openings 1104 and 1106. The length of the channel axis 1110 is L (measured between the centroids of the openings 1104 and 1106).

[0142] For the purposes of this disclosure, if the extension or protrusion does not reach the second surface 606, and if the vertical distance w from axis 1110 to the farthest point of the extension or protrusion away from axis 1110 is... p If the value is 0.05L or greater, the extension or protrusion of channel 1102 is defined as a "lateral protrusion". Figure 11 shows the vertical distance w of each lateral protrusion. p .

[0143] Generally speaking, for a given lateral protrusion, w p It can be 0.05L or more (e.g., 0.10L or more, 0.20L or more, 0.30L or more, 0.40L or more, 0.50L or more, 0.75L or more, 1.0L or more, 1.25L or more, 1.5L or more, 2.0L or more, 2.5L or more, 3.0L or more, 3.5L or more, 4.0L or more, 5.0L or more, or even more).

[0144] A given channel 1102 may include any number of lateral protrusions (e.g., none, one or more, two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, or even more). A main protrusion extending from the channel axis 1110 may also include secondary protrusions extending from the main protrusion, such that the individual channels have a branching "tree-like" structure. Within the filter member 602, the average number of lateral protrusions in each channel 1102 may be none, or 0.25 or more (e.g., 0.50 or more, 1.0 or more, 1.5 or more, 2.0 or more, 2.5 or more, 3.0 or more, 3.5 or more, 4.0 or more, 4.5 or more, 5.0 or more, 5.5 or more, 6.0 or more, 6.5 or more, 7.0 or more, 7.5 or more, 8.0 or more, or even more).

[0145] In some embodiments, the channels in the filter component may include one or more coating materials. For example, coating materials can be used to enhance the adsorption of viral particles and promote fluid flow through the component. Coatings can also be used to adjust the hydrophobic or hydrophilic properties of the component and / or adjust the ionic properties of the component. Generally, individual channels in the filter component may be without coating, include a single coating, or include multiple (e.g., two or more, three or more, four or more, five or more, or even more) coatings. Figure 12 is a schematic diagram illustrating a filter component 602 including a channel 1202 with two coatings 1204 and 1206. In Figure 12, each coating conforms to the surface of the internal channel. A variety of different coating materials can be used. Examples of such materials include, but are not limited to, cellulose and regenerated cellulose, hydrophilic polymers (e.g., polyethersulfone, polyethylene glycol), hydrophobic polymers (i.e., polyethylene, polypropylene, polystyrene), polypropylene glycol, other polyols, polyurethane, polymethyl methacrylate, and polyacrylic acid.

[0146] Typically, the coating applied to the channel walls of a filter element is relatively thin. For example, for a filter element having multiple channels, each channel has a maximum cross-sectional size measured in a plane orthogonal to the direction of fluid flow in the filter element, and the filter element has an average maximum cross-sectional size across all such channels. In some embodiments, the ratio of the average thickness of the coating material applied to the inner surface of the channel to the average maximum cross-sectional size of the channel is 0.2 or less (e.g., 0.15 or less, 0.10 or less, 0.05 or less, 0.04 or less, 0.03 or less, 0.02 or less, 0.01 or less, 0.005 or less, 0.004 or less, 0.003 or less, 0.002 or less, 0.001 or less).

[0147] Multi-layer filter

[0148] In some embodiments, the filter element 602 may be multilayered and may be effectively formed from two or more filter elements in contact with each other. Figure 13 is a schematic diagram showing a filter element 602 formed from three layers 602a-c. Although three layers are shown in Figure 13, more generally, the filter element 602 may be formed from two or more layers (e.g., three or more layers, four or more layers, five or more layers, six or more layers, seven or more layers, eight or more layers, nine or more layers, ten or more layers, or even more layers).

[0149] Layers 602a-c can each possess any of the properties described above. In other words, any of the thickness, layer and channel geometry, and other properties discussed herein can exist in any one or more layers of 602a-c. Between any two layers 602a-c, one or more channels formed in the upstream layer can be in direct fluid communication with one or more channels in the downstream layer. In this context, "direct fluid communication" means...

[0150] Multilayer filter components can offer advantages in many different operating environments. For example, in some embodiments, the first layer 602a may have a relatively small number of openings per unit area and a relatively smooth surface texture. This configuration allows fluid to move in a cross-flow direction on the surface of the first layer 602a to effectively “sweep” the surface, thereby preventing solids from accumulating on the surface that would otherwise hinder effective filtration. In some embodiments, the second layer 602b may be relatively porous, with a relatively large number of channels for capturing viral particles, and therefore has a relatively coarse texture. In some embodiments, the third layer 602c may have relatively small openings at the second surface (e.g., openings with a maximum cross-sectional size between about 20 nm and 30 nm), making the third layer effectively act as a size-cutoff filter for particles in the fluid.

[0151] Fiber geometry

[0152] As discussed above, filter element 602 is typically implemented as a layer in contact with hollow fibers through which process fluids flow. Generally, the outer diameter of the combination of hollow fibers and filter element 602 can be selected as needed to ensure sufficient cross-flow and tangential flow through the filter unit. In some embodiments, for example, the outer diameter may be 0.3 mm or greater (e.g., 0.4 mm or greater, 0.5 mm or greater, 0.6 mm or greater, 0.7 mm or greater, 0.8 mm or greater, 0.9 mm or greater, 1.0 mm or greater, 1.1 mm or greater, 1.2 mm or greater, 1.3 mm or greater, 1.4 mm or greater, 1.5 mm or greater).

[0153] The inner diameter of the hollow fiber can also be selected as needed. In some embodiments, for example, the inner diameter of the hollow fiber is 0.1 mm or greater (e.g., 0.2 mm or greater, 0.3 mm or greater, 0.4 mm or greater, 0.5 mm or greater, 0.6 mm or greater, 0.7 mm or greater, 0.8 mm or greater, 0.9 mm or greater, 1.0 mm or greater, or even greater). The inner diameter of the hollow fiber can be 0.001 mm or more smaller than the outer diameter of the combination of the hollow fiber and filter component 602 (e.g., 0.005 mm or more, 0.01 mm or more, 0.012 mm or more, 0.014 mm or more, 0.016 mm or more, 0.018 mm or more, 0.020 mm or more, 0.022 mm or more, 0.024 mm or more, 0.026 mm or more, 0.028 mm or more, 0.030 mm or more, 0.032 mm or more, 0.034 mm or more). More, 0.036mm or more, 0.038mm or more, 0.040mm or more, 0.042mm or more, 0.044mm or more, 0.046mm or more, 0.048mm or more, 0.05mm or more, 0.055mm or more, 0.060mm or more, 0.065mm or more, 0.070mm or more, 0.075mm or more, 0.080mm or more, 0.085mm or more, 0.090mm or more, 0.10mm or more, or even more).

[0154] Laminar tangential flow virus filtration

[0155] In the foregoing discussion, hollow fiber-based filter units were used to perform tangential flow virus filtration. Commercially available virus filters are implemented in this way and used in non-recirculating filtration assemblies. However, the filter elements described herein can also be used in laminar tangential filtration subsystems to achieve tangential flow virus filtration. Such subsystems offer several advantages over fiber-based filtration. First, laminar filter elements are typically easier to manufacture than tubular filter elements. Second, laminar filter elements with relatively large surface areas can be produced, and therefore can accommodate larger process fluid fluxes than fiber-based filter elements. Third, laminar filter units can include turbulence promoters (such as screens) that generate turbulent fluid flow over the filter element, thereby helping to “sweep” the surface of the filter element via cross-flowing process fluid.

[0156] Figure 14 is a schematic diagram illustrating an example of a layered tangential virus filtration unit 1402. Unit 1402 includes an inlet 1404 and an outlet 1406, a filter element 1410, a product stream outlet 1412, and a screen 1414 that acts as a turbulence promoter. During operation, process fluid enters through the inlet 1404 and flows to the outlet 1406 in the direction indicated by arrow 1408. When the cross-flowing process fluid interacts with the screen 1414, turbulence is generated in the flowing process fluid, which helps to remove solids from the surface of the filter element 1410.

[0157] A portion of the process fluid within the unit is driven by transmembrane pressure through filter member 1410, thereby generating a product stream that exits the filter member through product stream outlet 1412. The product stream is generally free of viral particles, which are retained and trapped within filter member 1410.

[0158] Generally, filter member 1410 may have any of the features described above in conjunction with filter member 602. That is, any of the thickness, layer and channel geometry, and other properties discussed herein may be present in layer 1410.

[0159] Other implementation plans

[0160] It should be understood that the foregoing description is intended to be illustrative and not to limit the scope of this disclosure, and that embodiments other than those explicitly described are within the scope of this disclosure.

Claims

1. A virus filter, comprising: A filter component, the filter component including a first surface and a second surface and having a thickness extending between the first surface and the second surface in a first direction; as well as A plurality of channels are formed in the filter component, each channel extending from the first surface to the second surface and including a channel axis. Each channel defines a unique path extending from a first opening in the first surface to a second opening in the second surface, the first opening and the second opening being unique for each channel, and the path does not intersect with the paths defined by other channels among the plurality of channels that pass through the thickness of the filter member; During use, the solution carrying the viral load flows in a direction parallel to the first surface, and at least a portion of the viral load enters the membrane through the first surface and propagates in the first direction. Wherein, for at least 50% of the channels in the filter component, the channel axis is oriented at an angle between 5 degrees and 85 degrees relative to the first direction.

2. The filter of claim 1, wherein the channel axis is oriented at an angle between 5 degrees and 75 degrees relative to the first direction.

3. The filter of claim 1, wherein the channel axis is oriented at an angle between 10 degrees and 60 degrees relative to the first direction.

4. The filter of claim 1, wherein for at least 70% of the channels in the filter member, the channel axis is oriented at an angle between 5 degrees and 85 degrees relative to the first direction.

5. The filter of claim 1, wherein for at least 90% of the channels in the filter member, the channel axis is oriented at an angle between 5 degrees and 85 degrees relative to the first direction.

6. The filter of claim 1, wherein the thickness of the filter element is 150 micrometers or greater.

7. The filter according to claim 1, wherein the thickness of the filter element is 300 micrometers or greater.

8. The filter according to claim 1, wherein the thickness of the filter element is 500 micrometers or greater.

9. The filter of claim 1, wherein each member of the plurality of channels includes an opening at the first surface, and wherein the ratio of the total area of ​​the openings to the total area of ​​the first surface is 0.10 or greater.

10. The filter of claim 9, wherein the ratio of the total area of ​​the openings to the total area of ​​the first surface is 0.20 or greater.

11. The filter of claim 9, wherein the ratio of the total area of ​​the openings to the total area of ​​the first surface is 0.30 or greater.

12. The filter of claim 1, wherein each member of the plurality of channels has a volume, and wherein the ratio of the total volume of the channels to the total volume of the member is 0.05 or greater.

13. The filter of claim 12, wherein the ratio of the total volume of the channels to the total volume of the component is 0.10 or greater.

14. The filter of claim 12, wherein the ratio of the total volume of the channels to the total volume of the component is 0.20 or greater.

15. The filter of claim 1, wherein for each of at least some of the plurality of channels, the member includes an opening at the first surface having a first cross-sectional area in the first surface, and the first cross-sectional area is smaller than a second cross-sectional area of ​​the member at a location between the first surface and the second surface.

16. The filter of claim 15, wherein the ratio of the first cross-sectional area to the second cross-sectional area is 0.95 or less.

17. The filter of claim 15, wherein the ratio of the first cross-sectional area to the second cross-sectional area is 0.85 or less.

18. The filter of claim 15, wherein the ratio of the first cross-sectional area to the second cross-sectional area is 0.75 or less.

19. The filter of claim 15, wherein the at least some members comprise at least 40% of the members of the plurality of channels.

20. The filter of claim 15, wherein the at least some members comprise at least 60% of the members of the plurality of channels.

21. The filter of claim 15, wherein the at least some members include all members of the plurality of channels.

22. The filter of claim 1, wherein the channel axes of the plurality of channels include an orientation distribution relative to the first direction.

23. The filter of claim 22, wherein the average orientation of the distribution is between 10 and 30 degrees relative to the first direction.

24. The filter of claim 22, wherein the average orientation of the distribution is between 30 and 50 degrees relative to the first direction.

25. The filter of claim 22, wherein the average orientation of the distribution is between 50 and 80 degrees relative to the first direction.

26. The filter of claim 22, wherein the full width at half maximum (FWHM) value of the orientation distribution is 60 degrees or less.

27. The filter of claim 26, wherein the FWHM value of the distribution is 40 degrees or less.

28. The filter of claim 26, wherein the FWHM value of the distribution is 15 degrees or less.

29. The filter of claim 1, wherein for each of at least some members of the plurality of channels, the member includes one or more secondary channels extending from the channel axis.

30. The filter of claim 29, wherein the one or more secondary channels extend from the channel axis at an angle between 10 degrees and 80 degrees relative to the channel axis along the secondary axis.

31. The filter of claim 29, wherein the one or more secondary channels extend from the channel axis at an angle between 50 and 90 degrees relative to the channel axis along the secondary axis.

32. The filter of claim 29, wherein one or more of the members comprise three or more secondary channels.

33. The filter of claim 29, wherein one or more of the members comprise five or more secondary channels.

34. The filter of claim 29, wherein the member comprises an average of five or more secondary channels.

35. The filter of claim 34, wherein the member comprises an average of seven or more secondary channels.

36. The filter of claim 1, wherein for each of at least some members of the plurality of channels, the member includes an opening at the first surface, the opening having a first cross-sectional area in the first surface and a maximum cross-sectional area different from the first cross-sectional area at a location between the first surface and the second surface.

37. The filter of claim 36, wherein the ratio of the first cross-sectional area to the maximum cross-sectional area is 0.50 or less.

38. The filter of claim 37, wherein the ratio of the first cross-sectional area to the maximum cross-sectional area is 0.30 or less.

39. The filter of claim 37, wherein the ratio of the first cross-sectional area to the maximum cross-sectional area is 0.10 or less.

40. The filter of claim 36, wherein the at least some members of the plurality of channels comprise 50% or more of the plurality of channels.

41. The filter of claim 40, wherein the at least some members of the plurality of channels comprise 80% or more of the plurality of channels.

42. The filter of claim 1, wherein for each of at least some members of the plurality of channels, the member comprises a maximum cross-sectional area and a minimum cross-sectional area at different locations along the channel axis, and wherein the ratio of the minimum cross-sectional area to the maximum cross-sectional area is 0.75 or less.

43. The filter of claim 42, wherein the ratio of the minimum cross-sectional area to the maximum cross-sectional area is 0.50 or less.

44. The filter of claim 42, wherein the ratio of the minimum cross-sectional area to the maximum cross-sectional area is 0.30 or less.

45. The filter of claim 1, wherein the first surface is planar and has a maximum dimension measured in the plane, and wherein the ratio of the maximum dimension to the thickness is 10 or greater.

46. ​​The filter of claim 45, wherein the ratio of the maximum dimension to the thickness is 20 or greater.

47. The filter of claim 1, wherein the porosity of the component is between 0.3 and 0.

9.

48. The filter of claim 1, wherein the member is formed of a first material, and each of at least some members of the plurality of channels includes a second material located on the inner surface of the member.

49. The filter of claim 48, wherein the first material is selected from polyvinylidene fluoride (PVDF), hydrophilic PVDF, and regenerated cellulose.

50. The filter of claim 48, wherein the second material is selected from cellulose, polyethersulfone, and polyethylene glycol.

51. The filter of claim 48, wherein the ratio of the average thickness of the second material on the inner surface of the member to the maximum cross-sectional dimension of the member is 0.2 or less.

52. The filter of claim 51, wherein the ratio of the average thickness of the second material on the inner surface of the member to the maximum cross-sectional dimension of the member is 0.1 or less.

53. The filter of claim 48, wherein the ratio of the average thickness of the second material on the inner surface of the member to the thickness of the member is 0.05 or less.

54. The filter of claim 53, wherein the ratio of the average thickness of the second material on the inner surface of the member to the thickness of the member is 0.02 or less.

55. The filter of claim 1, wherein the plurality of channels is a first plurality of channels, and wherein the filter component comprises: Including the first layer of the first plurality of channels; as well as The second layer includes multiple channels.

56. The filter of claim 55, wherein the second layer contacts the first layer.

57. The filter of claim 55, wherein at the interface between the first layer and the second layer, at least some members of the first plurality of channels are in fluid communication with at least some members of the second plurality of channels.

58. The filter of claim 55, wherein each of the second plurality of channels includes a channel axis, and wherein for at least 50% of the second plurality of channels in the second layer, the channel axis is oriented at an angle between 5 degrees and 90 degrees relative to the first direction.

59. The filter of claim 58, wherein the average orientation of the first plurality of channels relative to the first direction is different from the average orientation of the second plurality of channels relative to the first direction.

60. The filter of claim 59, wherein the average angle between the channel axis of the second plurality of channels and the first direction is greater than the average angle between the channel axis of the first plurality of channels and the first direction.

61. The filter of claim 59, wherein the average angle between the channel axis and the first direction for the second plurality of channels is less than the average angle between the channel axis and the first direction for the first plurality of channels.

62. The filter of claim 55, wherein the first layer is formed of a first material selected from polyvinylidene fluoride (PVDF), hydrophilic PVDF, and regenerated cellulose, and wherein the second layer is formed of a second material selected from cellulose and regenerated cellulose, polyethersulfone, polyethylene glycol, polyethylene, polypropylene, polystyrene, polypropylene glycol, polyurethane, polymethyl methacrylate, and polyacrylic acid.

63. The filter of claim 62, wherein the first material is different from the second material.

64. The filter of claim 55, wherein at least some of the first plurality of channels include a coating material on the inner surface of the at least some channels.

65. The filter of claim 64, wherein the coating material is selected from cellulose, polyethersulfone, and polyethylene glycol.

66. The filter of claim 55, wherein at least some of the second plurality of channels include a coating material on the inner surface of the at least some channels.

67. The filter of claim 64, wherein the coating material is selected from cellulose, polyethersulfone, and polyethylene glycol.

68. The filter of claim 55, wherein at least some of the first plurality of channels include a first coating material on the inner surface of the at least some of the first plurality of channels, and at least some of the second plurality of channels include a second coating material on the inner surface of the at least some of the second plurality of channels.

69. The filter of claim 55, wherein each member of the first plurality of channels includes an opening at the first surface, and each member of the second plurality of channels includes an opening at the interface between the first layer and the second layer, and wherein the average cross-sectional area of ​​the openings of the first plurality of channels is different from the average cross-sectional area of ​​the openings of the second plurality of channels.

70. The filter of claim 69, wherein the average cross-sectional area of ​​the openings of the first plurality of channels is greater than the average cross-sectional area of ​​the openings of the second plurality of channels.

71. The filter of claim 69, wherein the ratio of the total area of ​​the openings of the first plurality of channels at the first surface to the area of ​​the first surface is greater than the ratio of the total area of ​​the openings of the second plurality of channels at the interface to the area of ​​the interface.

72. The filter of claim 55, wherein each member of the first plurality of channels has a volume in the first layer, and each member of the second plurality of channels has a volume in the second layer, and wherein the ratio of the total volume of the first plurality of channels in the first layer to the volume of the first layer is greater than the ratio of the total volume of the second plurality of channels in the second layer to the volume of the second layer.

73. The filter of claim 55, wherein for each of at least some members of the second plurality of channels, the member has an opening having a first cross-sectional area at an interface between the first layer and the second layer and a second cross-sectional area at a position displaced from the interface along the channel axis, and wherein the first cross-sectional area is smaller than the second cross-sectional area.

74. The filter of claim 73, wherein the ratio of the first cross-sectional area to the second cross-sectional area is 0.85 or less.

75. The filter of claim 74, wherein the ratio of the first cross-sectional area to the second cross-sectional area is 0.50 or less.

76. The filter of claim 55, wherein each member of the second plurality of channels has an orientation defined by the channel axis of the member relative to the first direction, and wherein the full width at half maximum (FWHM) of the orientation distribution of the second plurality of channels is 20 degrees or less.

77. The filter of claim 76, wherein the orientation distribution of the second plurality of channels has an FWHM of 10 degrees or less.

78. A method for removing virus particles from a solution, the method comprising: (a) Passing a solution containing virus particles through a filter unit including filter components; (b) Capture the portion of the solution that passes through the filter member in a direction orthogonal to the flow direction of the solution being transported through the filter unit; (c) The remaining portion of the solution that did not pass through the filter member is conveyed into a storage tank; (d) A portion of the solution is recycled from the reservoir through the filter unit; as well as (e) Repeat steps (b)-(d) to capture multiple portions of the solution, wherein each captured portion of the solution passes through the filter element. The filter component has a thickness and includes a plurality of channels, each of which extends through the thickness of the filter component; Each channel defines a unique path extending from a first opening in a first surface of the filter member to a second opening in a second opposing surface of the filter member, the first opening and the second opening being unique for each channel, and the unique path not intersecting with unique paths defined by other channels among the plurality of channels that traverse the thickness of the filter member; and For each of at least 50% of the channels in the filter assembly, the channel axis is oriented at an angle between 5 and 85 degrees relative to the thickness direction of the filter assembly.

79. The method of claim 78, wherein conveying the remaining portion of the solution that has not passed through the filter member into the reservoir comprises: The remaining portion of the solution is pumped into the reservoir.

80. The method of claim 78, wherein recycling a portion of the solution from the reservoir through the filter unit comprises: Fluid pressure is applied to the reservoir to drive a portion of the solution from the reservoir to the filter unit.

81. The method of claim 80, further comprising maintaining a constant fluid pressure applied to the reservoir during the transfer of a portion of the solution from the reservoir to the filter unit.

82. The method of claim 81, further comprising maintaining the constant fluid pressure applied to the reservoir to recirculate each portion of the solution from the reservoir through the filter unit.

83. The method of claim 78, wherein the filter unit has a cylindrical shape, and wherein the filter component has a tubular shape.

84. The method of claim 83, wherein a portion of the solution captured passes through the filter member in one or more radial directions of the filter unit.

85. The method of claim 78, wherein each of the plurality of channels includes an opening at a first surface of the filter member, and wherein the ratio of the total area of ​​the openings to the total area of ​​the first surface is 0.10 or greater.

86. The method of claim 85, wherein the filter member is tubular, and wherein the first surface of the filter member is the surface of the tubular filter member.

87. The method of claim 78, wherein each of the plurality of channels has a volume, and the ratio of the total volume of the channels to the total volume of the filter components is 0.05 or greater.

88. The method of claim 78, wherein each of at least some of the plurality of channels includes an opening at a first surface of the filter member, the opening having a first cross-sectional area in the first surface, and the first cross-sectional area being smaller than a second cross-sectional area of ​​the channel at a location between the first and second surfaces of the filter member.

89. The method of claim 88, wherein the filter member is tubular, and wherein the first surface of the filter member is the surface of the tubular filter member.

90. The method of claim 88, wherein the ratio of the first cross-sectional area to the second cross-sectional area is 0.95 or less.

91. The method of claim 88, wherein the at least some channels comprise at least 40% of the plurality of channels.

92. The method of claim 78, wherein the channel axes of the plurality of channels comprise an orientation distribution relative to the thickness direction of the filter member, and wherein the average orientation of the distribution is selected from the group consisting of: between 10 and 30 degrees relative to the thickness direction; between 30 and 50 degrees relative to the thickness direction; and between 50 and 80 degrees relative to the thickness direction.

93. The method of claim 78, wherein each of at least some of the plurality of channels includes one or more secondary channels extending from the channel axis.

94. The method of claim 78, wherein the filter member is formed of a first material, and each of at least some of the plurality of channels includes a second material located on the inner surface of the channel.

95. The method of claim 94, wherein the ratio of the average thickness of the second material on the inner surface of the at least some channels to the maximum cross-sectional dimension of the at least some channels is 0.2 or less.

96. The method of claim 78, wherein the plurality of channels is a first plurality of channels, and wherein the filter component comprises: Including the first layer of the first plurality of channels; as well as The second layer includes multiple channels.

97. The method of claim 96, wherein the average orientation of the axes of the first plurality of channels relative to the thickness direction of the filter member is different from the average orientation of the axes of the second plurality of channels relative to the thickness direction of the filter member.

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