A deep filtration device and a method for clarifying a biological material liquid using the same

Abstract

The application relates to the field of filtering devices, in particular to a deep filtering device and a method for clarifying biological material liquid by applying the same, wherein the deep filtering device comprises at least two layers of deep filtering medium layers, adjacent deep filtering media are sequentially the first deep filtering medium layer and the second deep filtering medium layer from the liquid inlet end to the liquid outlet end of the deep filtering device; the mass proportion of the filter aid of the first deep filtering medium layer is X a , the mass proportion of the filter aid of the second deep filtering medium layer is X b , the ratio of X a to X b is 0.5-1.5; the tightness of the first area is T1, the tightness of the second area is T2, and the ratio of T1 to T2 is 0.3-1.5:1. The deep filtering device has better filtering effect, filtering efficiency and filtering load on the biological material liquid.

Description

Technical Field

[0001] This invention relates to the field of filtration devices, and more specifically, to a deep filtration device and a method for clarifying biological feed using the same. Background Technology

[0002] Monoclonal antibodies have become a dominant form in the biopharmaceutical industry due to their high specificity for specific diseases. The therapeutic antibody market has been growing rapidly, with numerous drug candidates under regulatory review. Over the past 30 years, regulatory agencies in the US and EU have approved approximately 100 monoclonal antibodies, and more next-generation antibody therapies are expected to be approved in the next decade, including antibody-drug conjugates, biosimilars, engineered antibodies, bispecific antibodies, antibody fragments, and antibody-like proteins. Chinese hamster ovary (CHO) cells are the most commonly used cell line in the industry due to their adaptability to growth in suspensions and serum-free media, as well as their high productivity and post-translational modifications. CHO cells are used to produce protein therapeutics, accounting for over 70% of total production; however, these biopharmaceuticals can also be produced in a variety of systems, including microbial, plant, insect, and other mammalian cell systems.

[0003] The protein of interest in biopharmaceuticals can be one of a variety of naturally or recombinantly expressed proteins. Other biopharmaceuticals that can be used as therapeutic vectors include viral particles such as adenovirus, adeno-associated virus (AAV), or lentivirus; bacterial phages or viral particles; exosomes; or synthetic lipid nanoparticles. Besides CHO cells, host cells used to produce these biopharmaceuticals include other mammalian cell types such as human embryonic kidney (HEK) cells, HeLa cells, or PER.C6 cells; bacteria such as Escherichia coli or Bacillus; insect cells such as Sf6; yeast cells; or plant cells such as tobacco. Regardless of the cell type or therapeutic vector used, the clarification and purification processes related to isolating the biopharmaceutical of interest from the host cells and other components produced by the host cells may share similarities.

[0004] The increasing demand for bioproducts has led to continuous improvements over the past decade in production, upstream cell culture titers, and techniques for characterizing impurities and contaminants. However, with the significant increase in the titers of bioproduct raw materials, the amount of biomass and cell debris they contain has also increased dramatically, placing higher demands on filters used to clarify these raw material solutions.

[0005] Traditional depth filters are used as the primary clarification step, removing cell debris and biomass impurities based on the size of the depth filter channel and the filter aids in the depth filter media. However, as cell density increases from 6 million cells / mL to over 50 million cells / mL, the flux of traditional depth filtration becomes impractical, easily leading to clogging in a short time, resulting in a significant reduction in filtration efficiency and lifespan. Therefore, what is needed is a depth filter that maintains optimal filtration performance, efficiency, and lifespan for the initial clarification of high-cell-density biological feedstock solutions. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a deep filtration device and a method for clarifying biological feed liquid using the same.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A depth filtration device includes at least two layers of depth filtration media, the depth filtration media comprising fibers and a filter aid, wherein the fibers are selected from cellulose fibers or synthetic fibers;

[0009] The adjacent deep filter media, from the liquid inlet end to the liquid outlet end of the deep filter device, are the first deep filter media layer and the second deep filter media layer, respectively.

[0010] The density of the first deep filter media layer and the second deep filter media layer both increase gradually from their respective inlet surfaces to their respective outlet surfaces.

[0011] The density of the first deep filter media layer is not greater than the density of the second deep filter media layer;

[0012] The mass ratio of the filter aid in the first deep filter media layer is X. a The mass ratio of the filter aid in the second deep filter media layer is X. b X a With X b The ratio is 0.5 to 1.5;

[0013] The area within 1 / 3 of the thickness of the first deep filter medium layer, which is the distance from the liquid outlet surface of the first deep filter medium layer, is the first region, and the density of the first region is T1. The area within 1 / 3 of the thickness of the second deep filter medium layer, which is the distance from the liquid inlet surface of the second deep filter medium layer, is the second region, and the density of the second region is T2. The ratio of T1 to T2 is 0.3 to 1.5:1.

[0014] In the same deep filter media layer, controlling the density of the deep filter media layer to gradually increase from the inlet to the outlet in its thickness direction allows the intercepting pore size at the front end near the inlet to be larger than that at the rear end near the outlet. This results in a larger dirt-holding space at the front end of the deep filter media layer, providing better pre-filtration and increasing the interception capacity of each deep filter media layer. Conversely, setting the density at the rear end near the outlet allows for a smaller intercepting pore size, ensuring better interception of impurities of the target particle size. Therefore, by controlling the gradual increase in density of each deep filter media layer, optimal flux, capacity, and interception effect can be achieved for each layer.

[0015] Along the flow direction of the filtered fluid in the depth filter, the density of the previous layer of depth filter media is controlled to be lower than that of the next layer. This helps to improve the targeting of each layer of depth filter media for the specific impurities to be intercepted, and avoids the excessive interception of larger impurity particles in the high-precision depth filter media layer, which would lead to a rapid decline in the flux and load of the depth filter, thereby increasing the filtration capacity and lifespan of the depth filter and reducing the operating cost of the depth filter.

[0016] The main function of filter aids is to provide complex flow channels to slow down the attenuation of flow rate during filtration and improve the interception effect of impurities. In this invention, as the density and filtration accuracy increase from the first deep filter media layer to the second deep filter media layer, the filtration resistance of the filtered fluid in the deep filtration device also gradually increases along the filtration direction. Therefore, by setting the mass ratio of filter aids in the second deep filter media layer to that in the first deep filter media layer within a certain range, the filtration resistance of the first deep filter media layer increases too rapidly over time, while also reducing the resistance of the second deep filter media layer to the filtered fluid, thereby further improving the throughput, capacity, interception effect, and filtration efficiency of the deep filtration device.

[0017] The first region refers to the area between the first deep filter media layer and the second deep filter media layer, while the second region refers to the area between the second deep filter media layer and the first deep filter media layer. Because it's difficult for deep filter media layers to achieve 100% interception of the target impurity particles, and even if 100% interception were achieved, a large number of small particles that should have been intercepted by the next deep filter media layer would also be trapped, significantly reducing the load capacity of the deep filter device and causing a rapid decrease in flow rate. Therefore, for the first deep filter media layer, a small amount of large particles that should have been intercepted by the first deep filter media layer will inevitably penetrate into the second deep filter media layer, causing it to become clogged too quickly, resulting in a rapid decrease in flow rate and a significant drop in load capacity. This invention improves the pre-filtration capability of the front end of the second deep filter media layer for slightly larger impurity particles by controlling the ratio of the tightness of the first region to the tightness of the second region within a certain range. At the same time, it is less likely to adversely affect the interception effect of the target impurity particles that the second deep filter media layer itself should intercept, thereby avoiding the second deep filter media layer from clogging too quickly and improving the overall filtration capacity and filtration efficiency of the deep filtration device.

[0018] Specifically, the density of the first zone affects the interception effect of the first deep filter media layer, while the density of the second zone affects the pre-filtration capacity of the second deep filter media layer for larger-diameter impurities. Therefore, if the ratio of the density of the first zone to the density of the second zone is too large, the first zone may become clogged too quickly due to excessive interception, affecting the overall capacity and utilization rate of the deep filter device. Conversely, if the second zone is too loose, larger-diameter impurities may easily enter areas outside the pre-filtration zone of the second deep filter media layer, causing the area where the second deep filter media layer intercepts target impurities to become clogged quickly, also affecting the throughput and utilization rate of the deep filter device. If the ratio of the density of the first zone to the density of the second zone is too small, the particle size of larger-diameter impurities that inevitably penetrate from the first deep filter media layer may still be too large compared to the pre-filtration capacity of the second deep filter media layer, failing to achieve a good pre-filtration effect. This will cause the second deep filter media layer to still become clogged quickly, resulting in a low overall filtration capacity and utilization rate of the deep filter device.

[0019] Furthermore, the density T of the first deep filter media layer a It is 0.2–0.4 g / cm³. 3 The density T of the second deep filter media layer b It is 0.3–0.5 g / cm³. 3 .

[0020] By controlling the tightness of the first and second deep filter media layers, the synergistic effect of the first and second deep filter media layers can be made more stable, resulting in more significant optimization of the flux, load, interception effect and filtration efficiency of the deep filtration device.

[0021] Furthermore, the mass percentage of the filter aid in the first deep filter media layer is X. a The percentage of filter aid in the second deep filter media layer is 30-70%; X is the mass percentage of filter aid in the second deep filter media layer. b It ranges from 40% to 80%.

[0022] By controlling the mass ratio of filter aids in the first and second deep filter media layers, it is possible to avoid excessive filter aid content in the first and second deep filter media layers, which would cause the filter aids to easily detach and be lost in the deep filter media layers, and to avoid excessive filter aid content, which would result in a weak optimization effect.

[0023] Furthermore, the mass percentage of filter aid X1 in the first region is 40-60%, and the mass percentage of filter aid X2 in the second region is 40-65%, with the ratio of X1 to X2 being 0.8-1.3.

[0024] Because filter aids have greater material rigidity, the mechanical strength of this region can be effectively controlled by adjusting their content ratio. Secondly, filter aids themselves have a relatively complex and abundant pore structure, which helps to improve the filtration flow rate of the deep filter media layer. This invention optimizes the mechanical strength and filtration flow rate of the regions where the first and second deep filter media layers are close to each other by controlling the mass ratio of filter aids in the first region, the second region, and the ratio of the mass ratios of filter aids in the first region and the second region.

[0025] Furthermore, the mass ratio of the region located at a distance of 1 / 3 of the thickness of the first deep filter medium layer from the liquid surface of the first deep filter medium layer is w1, and the mass ratio of the region located at a distance of 1 / 3 of the thickness of the second deep filter medium layer from the liquid surface of the second deep filter medium layer is w2, with w1:w2 being 0.85 to 1.2:1.

[0026] The ratio of w1 to w2 actually refers to the ratio of the magnitude of the change in the density gradient of the first deep filter media layer to the magnitude of the change in the density gradient of the second deep filter media layer; the larger the ratio, the greater the magnitude of the gradient change of the first deep filter media layer relative to the second deep filter media layer.

[0027] Both w1 and w2 need to be controlled within a suitable range: For a single layer, the larger the change in density gradient, the better the pre-filtration effect, and the better the flow rate and interception accuracy can be maintained; however, the change in density gradient should not be too large, as this will cause very dense accumulation at the end near the liquid outlet, resulting in excessively rapid blockage of impurities and excessively rapid decline in flow rate. The smaller the change in density gradient, the more uniform the fiber interlacing in all parts of the deep filter media layer, which is beneficial to improving flux, flow rate, and adsorption capacity of small particulate impurities; however, if the change is too small, it can easily lead to an undesirable decrease in filtration accuracy.

[0028] The ratio of w1 to w2 also needs to be controlled within a suitable range. For both layers, if either w1 or w2 is too large, it will reduce the space utilization of the two deep filter media layers. In other words, the overall load of the deep filter device will be too low, and it will reach saturation and blockage more quickly, thus reducing the filter life.

[0029] Furthermore, the hydrophobic adsorption and electrostatic adsorption of the first and second deep filter media layers both increase gradually from the liquid inlet to the liquid outlet along the thickness direction of the layer.

[0030] By controlling the gradient increase of the hydrophobic adsorption capacity and electrostatic adsorption of the first and second deep filter media layers along their respective thickness directions, the front end of each deep filter media layer can primarily rely on physical interception. This, combined with a gradient increase in density, further enhances the pre-filtration effect and dirt-holding capacity for large particles. Conversely, the rear end of the deep filter media layer utilizes stronger hydrophobic and electrostatic adsorption to more effectively intercept small particles, improving the interception efficiency and precision. Therefore, by controlling the gradient changes in hydrophobic and electrostatic adsorption, the interception precision and filtration capacity of each deep filter media layer are improved.

[0031] Furthermore, a 50 ppm yellow soap dye solution was supplied to the first and second deep filter media layers, respectively. When the absorbance of the permeate at a wavelength of 418 nm increased to 0.05 Å, the total volume of the permeate was A. a and A b A a ∶A b =0.1~1.5.

[0032] When the yellow dye solution passes through the deep filter paper, the yellow dye, carrying a negative charge, is adsorbed by the filter paper through positive charge adsorption. When the filter paper still carries a positive charge, the yellow dye content in the permeate flowing out of the filter paper is almost zero. However, when the absorbance of the permeate flowing out of the filter paper at a wavelength of 418 nm rises to 0.05 Å, it indicates that the positive charge within the filter paper has been largely neutralized by the yellow dye, causing the yellow dye to appear in the permeate. Therefore, measuring the total volume of the permeate can reveal the original positive charge content of the deep filter paper.

[0033] By controlling the electrostatic adsorption of the first deep filter media layer to be lower than that of the second deep filter media layer, it is possible to avoid strong adsorption of particulate impurities with strong negative charge (especially small particles with strong negative charge) in the first deep filter media layer. This would prevent the first deep filter media layer from adsorbing not only relatively large particles but also a large number of large and small particles with strong negative charge through electrostatic adsorption, leading to excessively rapid clogging of the first deep filter media layer and a decrease in the filtration efficiency and lifespan of the deep filter device.

[0034] Furthermore, a 50 ppm yellow dye solution is supplied to the first region of the first deep filter media layer and the second region of the second deep filter media layer. When the absorbance of the permeate at a wavelength of 418 nm rises to 0.05 A, the total volumes of the permeate are A1 and A2, respectively, with A1:A2 = 0.1 to 1.6.

[0035] The electrostatic adsorption of both the first and second deep filter media layers increases gradually along their thickness. The electrostatic adsorption of the first deep filter media layer near its outlet surface is stronger than that of the second deep filter media layer near its inlet surface. This prevents the second deep filter media layer from directly adsorbing negatively charged impurities that have penetrated from the first layer, thus avoiding rapid clogging. However, the electrostatic adsorption of the first deep filter media layer near its outlet surface should not be excessively stronger than that of the second deep filter media layer near its inlet surface. A significant difference in electrostatic adsorption can cause impurities to flow against the filtration direction, leading to undesirable clogging on the outlet surface of the first deep filter media layer and ultimately reducing the overall capacity and lifespan.

[0036] Furthermore, the first deep filter media layer has the following IvIg protein adsorption performance: 0.5 g / L of IvIg protein solution is supplied to the first deep filter media layer from the inlet side to capture IvIg protein, achieving a filtration rate of 100 L / m³. 2 When measuring the filtered IvIg protein solution, the concentration decrease was C. a ;

[0037] The second deep filter media layer has the following IvIg protein adsorption performance: A 0.5 g / L IvIg protein solution is supplied to the second deep filter media layer from the inlet surface to capture IvIg protein, achieving a filtration rate of 100 L / m³. 2 When measuring the filtered IvIg protein solution, the concentration decrease was C. b ;

[0038] C a ∶C b The value ranges from 0.2 to 1.25.

[0039] When IvIg protein passes through a depth filter paperboard, it is retained by the paperboard through non-specific hydrophobic interactions between the hydrophobic groups in the paperboard and the hydrophobic groups on the IvIg protein. While the paperboard also retains some IvIg protein through physical retention, this effect is negligible due to the significant difference in diameter between the paperboard pores and the protein. Therefore, the paperboard primarily adsorbs IvIg protein through hydrophobic interactions. The depth filter paperboard of this application, after filtering with a 0.5 g / L IvIg protein solution, shows a 5%–70% reduction in the IvIg protein concentration in the downstream filtrate, indirectly demonstrating the overall hydrophobic adsorption capacity of the depth filter paperboard.

[0040] By controlling the hydrophobic adsorption of the first deep filter media layer to be lower than that of the second deep filter media layer, it is possible to avoid strong adsorption of highly hydrophobic particulate impurities (especially small, highly hydrophobic particles) in the first deep filter media layer. This would prevent the first deep filter media layer from adsorbing not only relatively large particles but also a large number of highly hydrophobic large and small particles through hydrophobic adsorption, leading to excessively rapid clogging of the first deep filter media layer and a decrease in the filtration efficiency and lifespan of the deep filter device.

[0041] Furthermore, the first region of the first deep filter media layer has the following IvIg protein adsorption performance: when 0.5 g / L of IvIg protein solution is supplied to the first region of the first deep filter media layer from the inlet, IvIg protein is captured, and when the IvIg protein solution is filtered at 100 L / m2, the concentration reduction value is C1.

[0042] The second deep filter media layer has the following IvIg protein adsorption performance: A 0.5 g / L IvIg protein solution is supplied to the second deep filter media layer from the inlet surface to capture IvIg protein, achieving a filtration rate of 100 L / m³. 2 When measuring the filtered IvIg protein solution, the concentration decrease value was C2;

[0043] The C1:C2 ratio is 0.8 to 0.9.

[0044] The hydrophobic adsorption primarily originates from the exposed hydrophobic groups within the pores of the hydrophobic fibers and filter aids. The hydrophobic adsorption of both the first and second deep filter media layers increases gradually along their thickness, with the hydrophobic adsorption on the side of the first deep filter media layer closer to its outlet surface being stronger than that on the side of the second deep filter media layer closer to its inlet surface. This prevents the second deep filter media layer from directly adsorbing hydrophobic impurities that have penetrated from the first layer when the fluid filtered through the first layer enters it, thus avoiding rapid clogging of the second deep filter media layer. However, the hydrophobic adsorption effect of the first deep filter media layer near its liquid outlet surface should not be too strong than that of the second deep filter media layer near its liquid inlet surface. If the difference in hydrophobic adsorption effect is too large, it will easily cause impurities to flow in the opposite direction of the filtration process, which will easily cause undesirable blockage on the side of the first deep filter media layer near the liquid outlet surface, thus reducing the overall load capacity and lifespan.

[0045] Furthermore, the ratio of T1 to T2 is 0.7 to 1.1, and A... a With A b The ratio is 0.3 to 1.2.

[0046] By controlling the density ratio of the first and second zones, the physical interception effect of the deep filtration device on impurity particles in the biological feed liquid is improved. The biological feed liquid after passing through the first deep filtration media layer is essentially free of large-sized impurity particles, thus preventing the second deep filtration media layer from reaching its capacity too quickly and causing the overall filtration capacity of the deep filtration device to be low. Secondly, by controlling the charge of the second deep filtration media layer to be slightly higher than that of the first deep filtration media layer, the electrostatic adsorption of charged impurity particles by the deep filtration device is improved, ensuring that the biological feed liquid after passing through the first deep filtration media layer is essentially free of high-charge impurity particles. Through physical interception and electrostatic adsorption of small-sized, low-charge impurities, the second deep filtration media layer effectively removes impurities from the biological feed liquid, and the dirt-holding space in both the first and second deep filtration media layers is effectively utilized, thereby improving the filtration accuracy and effect of the deep filtration device for biological feed liquids containing a large number of charged impurities.

[0047] Furthermore, when the ratio of the tightness of the first region and the tightness of the second region of the deep filtration device is within the aforementioned range, and simultaneously the ratio of the electrostatic adsorption capacity of the first deep filtration media layer to the electrostatic adsorption capacity of the second deep filtration media layer is within the aforementioned range, the filtration flux, load, interception effect, and filtration efficiency of the deep filtration device for filtering biological liquid are effectively improved.

[0048] Furthermore, the ratio of T1 to T2 is 0.5 to 0.9, and the ratio of A1 to A2 is 0.4 to 0.95.

[0049] By controlling the density of the second zone to be slightly higher than that of the first zone, the depth filtration device can improve its ability to filter biological feed liquids containing mainly small-sized impurity particles. After passing through the first depth filtration media layer, the biological feed liquid contains almost only small-sized impurities. Subsequently, when passing through the second depth filtration media layer, because the density of the second zone is slightly higher than that of the first zone, the biological feed liquid filtered through the first depth filtration media layer can achieve higher interception accuracy when entering the second depth filtration media layer. This improves the overall filtration accuracy and effect of the depth filtration device for biological feed liquids containing mainly small-sized impurity particles.

[0050] Secondly, by simultaneously controlling the density of the second region to be slightly higher than that of the first region, and the charge of the second region to be higher than that of the first region, it is beneficial to improve the electrostatic adsorption and dirt-holding capacity of the first deep filter media layer for high-charge impurity particles. This allows for effective pre-filtration when the biological feed liquid contains a large amount of high-charge impurities. The impurity particles in the biological feed liquid after filtration by the first deep filter media layer are mainly small-sized, low-charge impurity particles. Since the charge of the second region is higher than that of the first region, it can more effectively adsorb and retain small-sized, low-charge impurity particles starting from the second region (i.e., the inlet end of the second deep filter media layer). Furthermore, as the density gradually increases, the probability of collision between small-sized, low-charge impurity particles and the exposed charged groups in the second deep filter media layer also increases, gradually enhancing the adsorption effect and thus achieving higher precision in the retention of the biological feed liquid. Therefore, when filtering biological feed liquids containing a large number of charged impurities, especially small-sized, weakly charged impurities, depth filtration devices have superior filtration accuracy, filtration effect, and filtration capacity.

[0051] Furthermore, by simultaneously controlling the density of the second region to be slightly higher than that of the first region, and the charge on the second region to be higher than that on the first region, the deep filtration device also has high filtration accuracy, filtration capacity, and filtration effect when filtering conventional biological liquid materials.

[0052] Furthermore, the ratio of T1 to T2 is 1.05 to 1.2, and the ratio of A1 to A2 is 0.5 to 0.98.

[0053] By controlling the density of the first region to be higher than that of the second region, a transition zone with lower density can be created between the first and second deep filter media layers. This allows the end of the second deep filter media layer near its inlet surface to have a certain pre-filtration area, enabling a small amount of large particle impurities that have leaked from the first deep filter media layer to be trapped in the pre-filtration area. This prevents the flow rate of the second deep filter media layer from decreasing too quickly and improves its filtration effect.

[0054] Secondly, the lower density of the second region compared to the first region helps reduce the filtration resistance when the filtered fluid enters the second deep filter media layer from the first. Because the second region has more voids than the first region, the filtered fluid passing through the first deep filter media layer can enter the second deep filter media layer more easily and quickly. This reduces the force exerted by the filtered fluid on the outlet and inlet surfaces of the first and second deep filter media layers, slowing the rate of increase in filtration resistance over time. Consequently, the required filtration pressure drop to achieve the same filtration capacity is reduced, thus extending the service life of the deep filtration device.

[0055] Furthermore, the effective pore size of each layer of the deep filter medium decreases gradually from the inlet end to the outlet end of the deep filter device.

[0056] The effective pore size of the first deep filter media layer and the second deep filter media layer decreases from the liquid inlet surface to the liquid outlet surface.

[0057] The first region and the second region are respectively supplied with suspensions of particles with uniform particle size. The minimum average particle size of the particles in the first region and the second region with a mechanical interception rate of more than 98% is P1 and P2, respectively; P1 < P2.

[0058] The effective pore size of impurity particles that the paperboard can intercept gradually decreases along its thickness. Furthermore, the closer the paperboard media is to the liquid outlet surface, the more likely some impurity particles that should have been intercepted by that layer will cross-flow and penetrate, resulting in the downstream filtrate containing some larger impurity particles. If the first and second deep filter media layers are arranged in a strictly decreasing gradient of effective pore size, then when the filtrate filtered by the first deep filter media layer enters the second deep filter media layer, because the effective pore size of the paperboard media on the side of the second deep filter media layer closest to the liquid inlet is already very small, some larger impurity particles that have cross-flowed or penetrated in the first deep filter media layer are more likely to quickly clog the liquid inlet side of the second deep filter media layer, thus reducing the overall capacity of the filter.

[0059] By making the effective pore size of the first region of the first deep filter media layer smaller than that of the second region of the second deep filter media layer, the side of the second deep filter media layer near the liquid inlet can provide a certain amount of dirt-holding capacity for these larger impurities, thereby preventing the second deep filter media layer from being clogged too quickly and increasing the overall load capacity. However, the effective pore size of the second deep filter media layer on the liquid inlet side cannot be too large, otherwise the utilization rate of the pre-filtration zone will be too low.

[0060] Furthermore, P1 is 0.02–5 μm; P2 is 1–20 μm; P1∶P2=1∶5–500.

[0061] When the effective pore size of the first region of the first deep filter media layer and the effective pore size of the second region of the second deep filter media layer are controlled under the above conditions, the utilization rate of the first and second deep filter media layers in the deep filtration device can reach a high level, which can effectively improve the load and filtration flow rate of the deep filtration device.

[0062] Furthermore, the fibers in the first deep filter media layer are polyacrylonitrile fibers, and the fibers in the second deep filter media layer are cellulose fibers; or the fibers in the first deep filter media layer are cellulose fibers, and the fibers in the second deep filter media layer are cellulose fibers; or the fibers in the first deep filter media layer are polyacrylonitrile fibers, and the fibers in the second deep filter media layer are cellulose fibers.

[0063] Furthermore, the filter aid is selected from one or more of diatomaceous earth, silica, perlite, and activated carbon.

[0064] Furthermore, a binder is added to the deep filter media layer, the binder comprising a water-soluble synthetic polymer based on urea or melamine-formaldehyde, a polyamino-polyamide-epioclosan polymer, or acetaldehyde-oxidized polyacrylamide resin.

[0065] A method for clarifying biopharmaceutical raw materials using the aforementioned depth filtration device, comprising rinsing the depth filtration device with ultrapure water at a rate of 100 L / m³. 2 Above this, further supply cells at a density of 5–50 × 10⁶. 6 Unclarified cell harvest fluid with an initial turbidity of 500-4000 NTU within the cell / ml range was clarified and filtered.

[0066] In summary, the present invention has the following beneficial effects:

[0067] First, a deep filtration device is obtained by stacking multiple layers of deep filter media with varying density gradients and different densities. By controlling the density ratio of the first and second regions of adjacent first and second deep filter media layers, the resulting deep filtration device can achieve a better balance between flux, load capacity, and interception effect.

[0068] Secondly, by further controlling the content of filter aids, hydrophobic adsorption, and electrostatic adsorption of the first and second deep filter media layers, and by further controlling the ratio of filter aid content, hydrophobic adsorption, and electrostatic adsorption of the first and second regions that are close to each other in the first and second deep filter media layers, the overall filtration capacity and filtration life of the deep filtration device can be improved. Detailed Implementation

[0069] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0070] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0071] Example

[0072] The parameter tests of the deep filtration media layer in this invention include compactness, charge, hydrophobic adsorption capacity, mass ratio of filter aid, and compactness, charge, hydrophobic adsorption capacity, and mass ratio of filter aid after being divided into three layers.

[0073] (1) Tightness test method

[0074] Tightness is calculated using the following formula:

[0075]

[0076] Where G is the mass of the sample tested using instruments such as an electronic precision balance, d is the thickness of the sample tested using an electric thickness gauge, and S is the area of ​​the sample.

[0077] (2) Charge test method

[0078] The depth filter media layer was cut into circular samples, with a sample cardboard thickness of 3.6 mm and a diameter of 47 mm. A negatively charged yellow soap dye was used as a standard reagent, and a 50 ppm solution was prepared with water. The 50 ppm yellow soap dye solution was supplied at a constant rate of 5 ml / min. When the absorbance of the permeate at 430 nm decreased to 0.05 A, the total volume A of the permeated yellow soap dye solution was measured.

[0079] (3) Test method for hydrophobic adsorption

[0080] The IvIg protein retention capacity can be calculated using the following formula:

[0081]

[0082] The IvIg protein retention capacity was tested using the following method:

[0083] Prepare a 0.5 g / L IVIg protein solution, and use a clamp to hold a sample with a cross-sectional area of ​​13 cm². 2 A circular sheet of paperboard is fed with an 1vIg protein solution from the feed side, with a filtration rate of 120 L / m³ and a filtration rate of 100 L / m³. 2 Then, the concentration z of the IvIg protein solution in the filtrate was measured.

[0084] (4) Test method for the mass ratio of filter aid

[0085] The filter aid content was tested using the following method:

[0086] The sample paperboard was heated in a muffle furnace at 1000±25℃ until constant weight was achieved, and the weight was recorded as m.

[0087] The mass percentage of the filter aid is calculated using the following formula:

[0088]

[0089] (5) Effective Filter Pore Size Test Method

[0090] A polystyrene microsphere suspension with uniform particle size (containing 5 wt% polystyrene microspheres, 0.5–1 mol / L sodium chloride, and pure water) is supplied to the first or second region. The minimum polystyrene microsphere particle size at which the first or second region can retain more than 95% of the particles in the polystyrene microsphere suspension is the effective filtration pore size of that region.

[0091] Example of preparation of depth filter media layer:

[0092] Type A deep filter media layer is obtained by vacuum-suctioning a slurry of cellulose fibers, diatomaceous earth filter aid, and binder into a pre-fabricated stack, followed by drying. The binder is a polyamino-polyamide-epoxychlorohydrin polymer. Type A deep filter media layer is mainly used as the first deep filter media layer, and in some embodiments, it can also be used as the second deep filter media layer. Examples of the preparation methods for various aspects of Type A deep filter media layer are shown in Table 1 below:

[0093] Table 1

[0094]

[0095]

[0096] The effective pore size P1 of the first region of A-12, A-13 and A-14 was found to be 4 μm.

[0097] Type B deep filter media is prepared by vacuum-suctioning a slurry of cellulose fibers, diatomaceous earth filter aid, and binder into a pre-fabricated stack, followed by drying. The binder is a polyamino-polyamide-epoxychlorohydrin polymer. Type B deep filter media is primarily used as a second deep filter media layer, but in some embodiments, it can also be used as a first deep filter media layer. Examples of the preparation methods for various aspects of Type B deep filter media are shown in Table 2 below.

[0098] Table 2

[0099]

[0100] The effective pore size P2 of the second region of B-1 was found to be 5 μm.

[0101] Type C deep filter media layers are prepared by vacuum-suctioning a slurry of polyacrylonitrile fibers, silica filter aid, and binder into a pre-fabricated stack, followed by drying. The binder is a polyamino-polyamide-epoxychlorohydrin polymer. Type C deep filter media layers are primarily used as the first deep filter media layer, but in some embodiments, they can also be used as the second deep filter media layer. Examples of the preparation methods for various types of Type C deep filter media layers are shown in Table 3 below.

[0102] Table 3

[0103]

[0104] Type D deep filter media layers are prepared by vacuum-suctioning a slurry of polyacrylonitrile fibers, silica filter aid, and binder into a pre-fabricated stack, followed by drying. The binder is a polyamino-polyamide-epoxychlorohydrin polymer. Type D deep filter media layers are primarily used as the second deep filter media layer, but in some embodiments, they can also be used as the first deep filter media layer. Examples of the preparation methods for various aspects of the Type D deep filter media layer are shown in Table 4 below.

[0105] Table 4

[0106]

[0107] Examples 1-19

[0108] A depth filtration device combining high and low precision includes two layers of depth filter media, arranged sequentially from the inlet to the outlet. The second depth filter media layer is of type B-1 or B-2, while the first depth filter media layer uses types A-1 to A-19. The physical characteristics of the depth filtration devices in Examples 1 to 19 are shown in Table 5 below.

[0109] Taking Example 1 as an example:

[0110] The density T of the first deep filter media layer a It is 0.32 g / cm 3 The density T of the second deep filter media layer b 0.40 g / cm 3 .

[0111] The mass ratio of the filter aid in the first deep filtration media layer is X. a The percentage of filter aid in the second deep filtration media layer is 45%; X b It is 55%.

[0112] The adsorption capacity C of the first deep filter media layer a The adsorption capacity C of the second deep filter media layer is 4.6%. b It is 4.8%.

[0113] The amount of soap-yellow dye adsorbed in the first deep filtration medium layer, A a The amount of soap-yellow dye adsorbed in the second deep filtration medium layer is 40ml; A b It is 100ml.

[0114] The first deep filter media layer and the second deep filter media layer are each cut into three equal parts along the thickness direction. The cut layer of the first deep filter media layer that is close to the second deep filter media layer is the first region, and the cut layer of the second deep filter media layer that is close to the first deep filter media layer is the second region.

[0115] The density T1 of the first region is 0.33 g / cm³. 3 The density T2 of the second region is 0.38 g / cm³. 3 .

[0116] The tightness of the first zone (X1) is 50%, and the tightness of the second zone (X2) is 50%.

[0117] The tightness of the first area A1 is 20ml, and the tightness of the second area A2 is 25ml.

[0118] The tightness C1 of the first region is 3.2%, and the tightness C2 of the second region is 4.1%.

[0119] The first and second deep filter media layers were each cut into three equal parts along their thickness direction. The mass percentage of the layers near the liquid inlet of the first and second deep filter media layers was measured. The mass percentage of the region at a distance of 1 / 3 of the thickness of the first deep filter media layer from the liquid outlet was w1, and the mass percentage of the region at a distance of 1 / 3 of the thickness of the second deep filter media layer from the liquid outlet was w2. The ratio of w1 to w2 was 1.01.

[0120] A method for clarifying biopharmaceutical raw materials using the aforementioned depth filtration device, comprising rinsing the depth filtration device with ultrapure water at a rate of 100 L / m³. 2 Above this, further supply cells at a density of 5–50 × 10⁶. 6 Unclarified cell harvest fluid with an initial turbidity of 500-4000 NTU within the cell / ml range is clarified and filtered. A cell density of 50 × 10⁻⁶ cells / ml is preferred. 6 Unclarified cell harvest fluid with an initial turbidity of 4000 NTU and a volume of cells / ml was supplied to a deep filtration unit for clarification.

[0121] Table 5

[0122]

[0123]

[0124] Example 20

[0125] A depth filtration device with a combination of high and low precision includes two layers of depth filter media, which are arranged sequentially from the inlet to the outlet. The second depth filter media layer is a D-1 type, while the first depth filter media layer is an A-5 type. The physical characteristics of the depth filtration device in Example 20 are shown in Table 6 below.

[0126] Table 6

[0127] Example 20 C-1 / B-1 1.25 0.40 0.45 1.02 0.72 1.38

[0128] The deep filtration device in this embodiment is preferably used for filtering biological feed liquids containing a large amount of hydrophobic protein impurities, and has a good impurity removal effect.

[0129] Example 21

[0130] A depth filtration device with a combination of high and low precision includes two layers of depth filter media, which are arranged sequentially from the inlet to the outlet. The second depth filter media layer is a D-1 type, while the first depth filter media layer is a C-1 type. The physical characteristics of the depth filtration device in Example 21 are shown in Table 7 below.

[0131] Table 7

[0132] Example 21 C-1 / D-1 1.30 0.48 0.39 0.91 0.78 1.25

[0133] The deep filtration device in this embodiment is preferably used for filtering biological feed liquids containing a large amount of hydrophobic protein impurities, and has a good impurity removal effect.

[0134] Comparative Examples 1-4

[0135] A depth filtration device with a combination of high and low precision includes two layers of depth filter media, which are arranged sequentially from the inlet to the outlet end as a first and a second depth filter media layer. The second and first depth filter media layers are configured using the combinations shown in Table 8 below. Furthermore, the physical characteristics of the depth filtration devices in Comparative Examples 1-4 are specifically shown in Table 8 below.

[0136] Table 8

[0137] Comparative Example 1 A-20 / B-1 0.83 0.41 0.20 0.98 0.80 0.247 Comparative Example 2 A-21 / B-1 0.86 0.39 1.90 0.96 0.82 2.024 Comparative Example 3 A-22 / B-1 0.30 0.39 0.83 0.97 0.86 0.950 Comparative Example 4 A-23 / B-1 1.60 0.38 0.84 1.01 0.83 0.865

[0138] Verification method:

[0139] I. Unclarified non-expressing cell culture medium (CCF) was obtained by growing cells from the Chinese hamster ovary (CHO) cell line to the required density in a 10L bioreactor (New Brunswick Scientific, Edison, NJ) and harvesting them at 80% viability.

[0140] II. Filtration Capacity Test

[0141] First, the depth filtration device is filled with 50L of ultrapure water at a filtration rate of 600L / m². 2 Rinse at 100 L / min to wet the filter media and flush away extractable material. The unclarified cell harvest fluid A, with an initial turbidity of 2000 NTU and a turbidity of 200 NTU after centrifugation, is then rinsed at 100 L / min. 2 Supply the deep filtration unit at a rate of / h until the pressure differential of the deep filtration unit reaches 20psig, and test the turbidity of the filtrate.

[0142] First, the depth filtration device is filled with 50L of ultrapure water at a filtration rate of 600L / m². 2Rinse at 100 L / min to wet the filter media and flush away extractable material. The unclarified cell harvest medium B, with an initial turbidity of 3000 NTU and a turbidity of 180 NTU after centrifugation, is then rinsed at 100 L / min. 2 Supply the deep filtration unit at a rate of / h until the pressure differential of the deep filtration unit reaches 20psig, and test the turbidity of the filtrate.

[0143] III. Filter Load Capacity Test

[0144] First, the depth filtration device is filled with 50L of ultrapure water at a filtration rate of 600L / m². 2 Rinse at 100 L / min to wet the filter media and flush away extractable material. The unclarified cell harvest fluid A, with an initial turbidity of 2000 NTU and a turbidity of 200 NTU after centrifugation, is then rinsed at 100 L / min. 2 The solution is supplied to the deep filtration unit at a rate of / h until the turbidity of the filtered solution reaches 20 NTU. The volume of the filtered solution is recorded, and the DNA content in the filtrate is tested to obtain the DNA removal rate.

[0145] First, the depth filtration device is filled with 50L of ultrapure water at a filtration rate of 600L / m². 2 Rinse at 100 L / min to wet the filter media and flush away extractable material. The unclarified cell harvest medium B, with an initial turbidity of 3000 NTU and a turbidity of 180 NTU after centrifugation, is then rinsed at 100 L / min. 2 The solution is supplied to the deep filtration unit at a rate of / h until the turbidity of the filtered solution reaches 20 NTU, at which point the volume of the filtered solution is recorded.

[0146] Table 9

[0147]

[0148] Conclusion: Through comparison between the examples and the comparative examples, it can be seen that the density of the first deep filter media layer and the second deep filter media layer increases in a gradient. At the same time, when the density of the first region and the second region is within the range of the present invention, the adsorption effect of the deep filtration device on particulate impurities such as cell debris in biological feed liquid is improved, and the overall adsorption load is also optimized.

[0149] By comparing Examples 6-14 with other examples, it can be seen that when the range of T1:T2 is preferably within 0.7 to 1.1, and A... a ∶A b When the turbidity is within the range of 0.3 to 1.2, the filtration effect of the deep filtration device on the biological feed liquid is further enhanced, the turbidity is reduced to a greater extent, and the space utilization rate in the deep filtration device is higher, so that the load can also be further improved.

[0150] By comparing Examples 4-8 with other examples, it can be seen that when the ratio of T1 to T2 is 0.5-0.9 and the ratio of A1 to A2 is 0.4-0.95, the removal rate of DNA by the deep filtration device is improved, and the removal effect of the deep filtration device on charged impurities in biological feed liquid is enhanced.

[0151] By comparing Examples 10-16 with other examples, it can be seen that when the ratio of T1 to T2 is 1.05-1.2 and the ratio of A1 to A2 is 0.5-0.98, the deep filtration device improves the filtration effect and increases the filtration capacity of biological feed liquid with high turbidity and a large number of large-sized impurity particles.

[0152] A comparison of Examples 1, 2, and 19 shows that, in addition to controlling the ranges of T1 and T2 and X, the present invention also... a ∶X b By controlling the range of w1:w2 of the first deep filter media layer and the second deep filter media layer, the utilization rate of the dirt-holding space in the deep filter device can be effectively improved, thereby increasing the filtration capacity of the biological liquid.

[0153] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A depth filtration device, characterized in that, The filter includes at least two layers of deep filter media, the deep filter media comprising fibers and filter aids, the fibers being selected from cellulose fibers or synthetic fibers; The adjacent deep filter media, from the liquid inlet end to the liquid outlet end of the deep filter device, are the first deep filter media layer and the second deep filter media layer, respectively. The density of the first deep filter media layer and the second deep filter media layer both increase gradually from their respective inlet surfaces to their respective outlet surfaces. The density of the first deep filter media layer is not greater than the density of the second deep filter media layer; The mass ratio of the filter aid in the first deep filter media layer is X. a The mass ratio of the filter aid in the second deep filter media layer is X. b X a With X b The ratio is 0.5 to 1.5; The area within 1 / 3 of the thickness of the first deep filter medium layer, which is the distance from the liquid outlet surface of the first deep filter medium layer, is the first region, and the density of the first region is T1. The area within 1 / 3 of the thickness of the second deep filter medium layer, which is the distance from the liquid inlet surface of the second deep filter medium layer, is the second region, and the density of the second region is T2. The ratio of T1 to T2 is 0.3 to 1.5:

1.

2. The depth filtration device according to claim 1, characterized in that, T density of the first deep filter media layer a It is 0.2–0.4 g / cm³. 3 The density T of the second deep filter media layer b It is 0.3–0.5 g / cm³. 3 .

3. The depth filtration device according to claim 1, characterized in that, The mass percentage of filter aid in the first deep filter media layer X a The proportion of filter aid in the second deep filter media layer is 30-70%; b It ranges from 40% to 80%.

4. A depth filtration device according to claim 3, characterized in that, The mass percentage of filter aid X1 in the first region is 40-60%, and the mass percentage of filter aid X2 in the second region is 40-65%, with the ratio of X1 to X2 being 0.8-1.

3.

5. A depth filtration device according to claim 1, characterized in that, The mass ratio of the region located at a distance of 1 / 3 of the thickness of the first deep filter medium layer from the liquid surface of the first deep filter medium layer is w1, and the mass ratio of the region located at a distance of 1 / 3 of the thickness of the second deep filter medium layer from the liquid surface of the second deep filter medium layer is w2, with w1:w2 being 0.85 to 1.2:

1.

6. A depth filtration device according to claim 1, characterized in that, The hydrophobic adsorption and electrostatic adsorption of the first and second deep filter media layers both increase gradually from the liquid inlet to the liquid outlet along the thickness direction of the layer.

7. A depth filtration device according to claim 6, characterized in that, A 50 ppm yellow soap dye solution was supplied to the first and second deep filter media layers, respectively. When the absorbance of the permeate at a wavelength of 418 nm increased to 0.05 A, the total volume of the permeate was A. a and A b A a ∶A b =0.1~1.

5.

8. A depth filtration device according to claim 7, characterized in that, A 50 ppm yellow dye solution was supplied to the first region of the first deep filter media layer and the second region of the second deep filter media layer. When the absorbance of the permeate at a wavelength of 418 nm increased to 0.05 A, the total volumes of the permeate were A1 and A2, respectively, with A1:A2 = 0.1 to 1.

6.

9. A depth filtration device according to claim 6, characterized in that, The first deep filter media layer has the following IvIg protein adsorption performance: A 0.5 g / L IvIg protein solution is supplied to the first deep filter media layer from the inlet side to capture IvIg protein, achieving a filtration rate of 100 L / m³. 2 When measuring the filtered IvIg protein solution, the concentration decrease was C. a ; The second deep filter media layer has the following IvIg protein adsorption performance: A 0.5 g / L IvIg protein solution is supplied to the second deep filter media layer from the inlet surface to capture IvIg protein, achieving a filtration rate of 100 L / m³. 2 When measuring the filtered IvIg protein solution, the concentration decrease was C. b ; C a ∶C b The value ranges from 0.2 to 1.

25.

10. A depth filtration device according to claim 9, characterized in that, The first region of the first deep filter media layer has the following IvIg protein adsorption properties: A 0.5 g / L IvIg protein solution is supplied to the first region of the first deep filter media layer from the inlet surface to capture IvIg protein, achieving a filtration rate of 100 L / m³. 2 When measuring the filtered IVIg protein solution, the concentration decrease value was C1; The second deep filter media layer has the following IvIg protein adsorption performance: A 0.5 g / L IvIg protein solution is supplied to the second deep filter media layer from the inlet surface to capture IvIg protein, achieving a filtration rate of 100 L / m³. 2 When measuring the filtered IvIg protein solution, the concentration decrease value was C2; The C1:C2 ratio is 0.8 to 0.

9.

11. A depth filtration device according to claim 7, characterized in that, The ratio of T1 to T2 is 0.7 to 1.1, and A a With A b The ratio is 0.3 to 1.

2.

12. A depth filtration device according to claim 8, characterized in that, The ratio of T1 to T2 is 0.5 to 0.9, and the ratio of A1 to A2 is 0.4 to 0.

95.

13. A depth filtration device according to claim 8, characterized in that, The ratio of T1 to T2 is 1.05 to 1.2, and the ratio of A1 to A2 is 0.5 to 0.

98.

14. A depth filtration device according to claim 1, characterized in that, The effective pore size of each layer of the deep filter media decreases gradually from the inlet end to the outlet end of the deep filter device. The effective pore size of the first deep filter media layer and the second deep filter media layer decreases from the liquid inlet surface to the liquid outlet surface. The first region and the second region are respectively supplied with suspensions of particles with uniform particle size. The minimum average particle size of the particles in the first region and the second region with a mechanical interception rate of more than 98% is P1 and P2, respectively; P1 < P2.

15. A depth filtration device according to claim 14, characterized in that, The P1 is 0.02–5 μm; the P2 is 1–20 μm; P1∶P2=1∶5–500.

16. A depth filtration device according to claim 1, characterized in that, The fibers in the first deep filter media layer are polyacrylonitrile fibers, and the fibers in the second deep filter media layer are cellulose fibers; or the fibers in the first deep filter media layer are cellulose fibers, and the fibers in the second deep filter media layer are cellulose fibers; or the fibers in the first deep filter media layer are polyacrylonitrile fibers, and the fibers in the second deep filter media layer are cellulose fibers.

17. A depth filtration device according to claim 1, characterized in that, The filter aid is selected from one or more of diatomaceous earth, silica, perlite, and activated carbon.

18. A depth filtration device according to claim 1, characterized in that, The deep filter media layer also contains a binder comprising a water-soluble synthetic polymer based on urea or melamine-formaldehyde, a polyamino-polyamide-epoxychlorohydrin polymer, or acetaldehyde-acidified polyacrylamide resin.

19. A method for clarifying biological feed liquid using the deep filtration device according to any one of claims 1 to 16, characterized in that, Rinse the depth filtration unit with ultrapure water 100L / m 2 Above this, further supply cells at a density of 5–50 × 10⁶. 6 Unclarified cell harvest fluid with an initial turbidity of 500-4000 NTU within the cell / ml range was clarified and filtered.

Images