Particles for making a liquid contact layer, method of making, and multilayer co-extruded bioreactor film made therefrom

Abstract

The application discloses a preparation method of particles for preparing a liquid contact layer, characterized in that the method comprises the following steps: adding metallocene polyethylene and fumed silica into a blender respectively for stirring to obtain a mixture; and adding the mixture into an extruder for hot melt extrusion and underwater cutting to obtain the particles for preparing the liquid contact layer. In addition, the application also discloses a disposable bioreactor membrane material prepared from the particles. The disposable bioreactor membrane material has the advantages of high tensile strength, good barrier property, high transparency and good flexibility.

Description

Technical Field

[0001] This invention relates to the field of bioreactor packaging technology, and in particular to particles for preparing liquid contact layers, preparation methods, and multilayer co-extruded bioreactor membranes obtained therefrom. Background Technology

[0002] The biopharmaceutical industry is shifting from traditional stainless steel containers to disposable bioprocess bag systems. Biopharmaceutical research and development requires numerous reactors, incubators, transfer devices, etc.; these are typically made of stainless steel, which is expensive, difficult to clean after use, has cumbersome accessories, occupies a large area, and is not easily moved. Therefore, disposable bioprocess bags are gradually replacing the former.

[0003] Currently, the disposable bioprocess bags used with bioreactors are pre-sterilized and disinfected, which facilitates the cultivation of active cells, occupies a small area, improves work flexibility and efficiency, reduces the need for cleaning steps in the production process, and avoids the uncertainty of cross-infection caused by inadequate cleaning during use.

[0004] Suitable for scientific research, university experiments, and production enterprises for cell culture and sample preparation, disposable bioprocess bag membrane is made by multi-layer co-extrusion equipment. The production process of bioprocess bags requires multiple steps and has strict requirements for the biocompatibility, gas barrier properties, and chemical stability of the biofilm.

[0005] Therefore, there is an urgent need for a disposable bioreactor membrane material with higher cell culture efficiency and biocompatibility, as well as high tensile strength, good barrier properties, high transparency, and good toughness. Summary of the Invention

[0006] The purpose of this invention is to provide particles for preparing liquid contact layers, a preparation method thereof, and multilayer co-extruded bioreactor membranes made therefrom, thereby solving one or more of the aforementioned problems in the prior art.

[0007] In a first aspect, the present invention provides a method for preparing particles for a liquid contact layer, comprising the following steps:

[0008] Metallocene polyethylene and fumed silica were added separately to a mixer and stirred to obtain a mixture.

[0009] The mixture is added to an extruder, the barrel temperature is controlled at 150-200℃ and the die temperature is controlled at 180-220℃, and the temperature is maintained for 30-60 minutes. The main machine speed is 250-450 r / min. After hot melt extrusion and water cooling, the traction speed of the pelletizer is 90-225 m / min, thereby obtaining the particles used to prepare the liquid contact layer.

[0010] In some implementations, the stirring rate is controlled at 1000 r / min and the stirring time is 3-5 min.

[0011] In some implementations, the metallocene polyethylene content is 50-90% by mass, and the fumed silica content is 10-50% by mass. If the fumed silica (SiO2) content is too high, it will affect light transmittance, making it difficult to observe cell growth. As long as it is uniformly dispersed in the resin, it can improve resin properties, making the film denser and increasing its strength and toughness. Fumed silica (SiO2) can reflect ultraviolet light, reducing resin degradation and thus delaying material aging.

[0012] Secondly, the particles for preparing liquid contact layers provided by the present invention are prepared by the following method, specifically:

[0013] Metallocene polyethylene and fumed silica were added separately to a mixer and stirred to obtain a mixture.

[0014] The mixture is added to an extruder, and after hot melt extrusion and underwater pelleting, the particles used to prepare the liquid contact layer are obtained.

[0015] Thirdly, the multilayer co-extruded bioreactor membrane material provided by the present invention comprises, from the outside to the inside:

[0016] A protective layer, wherein the protective layer is made of linear low-density polyethylene and metallocene polyethylene;

[0017] The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, preferably ethylene-vinyl acetate copolymer;

[0018] A gas barrier layer, wherein the gas barrier layer is selected from polyvinyl alcohol;

[0019] The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, preferably ethylene-vinyl acetate copolymer;

[0020] A liquid contact layer comprising an outer layer and an inner layer, the outer layer being made of the particles described above for preparing the liquid contact layer, and the inner layer being made of metallocene polyethylene.

[0021] Specifically: The protective layer needs to possess certain puncture and bending resistance to ensure reliability during use. The gas barrier layer needs to isolate gases such as carbon dioxide, oxygen, and water vapor, reducing the impact of the external environment on cell growth. The liquid contact layer needs to meet the requirements of cell culture and growth in biopharmaceutical production processes, while inhibiting the leaching of substances from the membrane that are detrimental to cell growth. It should have high drug-liquid compatibility, stable biosafety, and also possess certain adhesive properties and provide good heat-sealing properties to prevent drug leakage during cell culture. The adhesive layer provides good adhesion.

[0022] In existing technologies, some patents use one or a mixture of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ultra-low-density polyethylene (ULPE) for the liquid contact layer. While their tensile strength and heat-sealing performance meet basic performance requirements, they result in low cell culture densities. Culture media containing fumed SiO2 can stimulate cell growth and metabolism, accelerating cell division; however, the use of fumed SiO2 in polymer films has not been reported. It is well known that when fumed SiO2 powder is added to a polymer and extruded, it is uniformly dispersed within the polymer matrix. This highly dense encapsulation prevents cells from contacting the fumed SiO2. This invention utilizes an improved multi-layer co-extrusion process to enrich the surface of the liquid contact layer with fumed SiO2, allowing for easy contact between cells and the culture medium during later use, thereby increasing cell growth rates.

[0023] Furthermore, the liquid contact layer of the present invention employs two layers, inner and outer, wherein metallocene polyethylene and fumed silica are blended in the above proportion and serve as the outer layer of the liquid contact layer, allowing more fumed silica to accumulate on the surface of the liquid contact layer without affecting transparency.

[0024] In some implementations, the following substances can also be used to replace fumed silica to improve cell growth rate, such as calcium phosphate (Ca3(PO4)2), calcium carbonate (CaCO3), calcium sulfate (CaSO4), and calcium silicate (CaSiO4).

[0025] In some embodiments, the thickness of the protective layer is 50-80 μm, and the mass content of metallocene polyethylene in the protective layer is controlled to be 10-40% and the mass content of linear low-density polyethylene is 60-90%.

[0026] Among them, metallocene polyethylene was purchased from Mitsui Chemicals, ExxonMobil, Daerim Chemical, and PetroChina; linear low-density polyethylene was purchased from Yangzi Petrochemical, Shanghai SECCO, and Tianjin United.

[0027] Specifically, metallocene polyethylene has better transparency and higher resin cleanliness than ordinary PE, making it easier to observe cell cultures. Linear low-density polyethylene has higher strength, toughness, tear resistance, and puncture resistance, is easy to process, and has better optical properties in films, making it suitable for use as a protective layer.

[0028] In some embodiments, the thickness of the adhesive layer is 10-18 μm. The thickness of the adhesive layer does not need to be too thick; it is sufficient to provide good bonding to other functional layers.

[0029] The ethylene-vinyl acetate copolymer was purchased from DuPont (USA), Mitsui (Japan), and LG (South Korea).

[0030] Furthermore, ethylene-vinyl acetate copolymer (EVA) is also suitable because EVA possesses excellent flexibility, high transparency, good surface gloss, strong chemical stability, good anti-aging and ozone resistance, and is non-toxic. In multilayer co-extrusion, EVA is molded at temperatures between 160℃ and 200℃, which is closer to the temperatures of the protective layer, liquid contact layer, and gas barrier layer, resulting in better bonding performance.

[0031] In some implementations, the thickness of the gas barrier layer is 20-70 μm, and the thickness is adjusted according to the actual situation. If the thickness is insufficient, it will not be effective in controlling oxygen and water vapor permeability. If it is too thick, it will not significantly improve the barrier performance.

[0032] The polyvinyl alcohol (PVA) used in the gas barrier layer was sourced from synthetic chemistry companies, Changchun Company, and Kuraray (Japan). PVA has high gas permeability, effectively preventing gas exchange between the packaged material and the external environment. Its high transparency and good gloss allow for clearer visualization of cell culture. It also exhibits good resistance to ultraviolet radiation and radiation, withstanding beta-ray sterilization.

[0033] In some embodiments, the thickness of the liquid contact layer is 150-250 μm;

[0034] The fumed silica was purchased from Jiuding Chemical, Kaiyin Chemical, Cabot Corporation (USA), and Tokuyama Corporation (Japan), and its specific surface area was 100-400 m². 2 / g.

[0035] The liquid contact layer primarily promotes cell growth and exhibits excellent weldability. Metallocene polyethylene has a lower initial heat-sealing temperature than ordinary PE, higher heat-sealing strength, and shorter heat-sealing time. It provides excellent sealing, significantly reducing leakage and breakage. Adding an appropriate amount of fumed silica (SiO2) does not affect transparency, and it significantly improves strength, toughness, waterproofing, and anti-aging properties, thus enhancing its effectiveness in biological cell culture.

[0036] Due to the special environment in which bioreactor membranes are used, there are strict limitations on the functional layers of the membrane. Before use, the process bags must be sterilized by ethylene oxide irradiation, electron beam irradiation, or gamma ray treatment. During this process, the membrane material must not undergo any physical or chemical changes; and no low-molecular-weight substances must precipitate or dissolve during cell culture.

[0037] By adjusting the thickness of the bioreactor membrane and adding an appropriate amount of fumed silica to the liquid contact layer, the mechanical strength decreases if the cell density is met; conversely, if the mechanical strength is met, the cell density does not meet the requirements. To better address this issue, the liquid contact layer is divided into an outer layer and an inner layer. The inner layer is made of metallocene polyethylene, and the outer layer is made of the aforementioned liquid contact layer particles, specifically metallocene polyethylene and fumed silica. This approach can simultaneously satisfy both cell density and mechanical properties.

[0038] Fourthly, the method for preparing the multilayer co-extruded bioreactor membrane material provided by the present invention includes the following steps:

[0039] Each extruder is heated to a temperature of 120-240℃ and held at that temperature for 30-90 minutes.

[0040] Add each raw material to the corresponding feeder;

[0041] By gradually adjusting the speed, the membrane material of the multilayer co-extruded bioreactor is obtained through melting, extrusion and casting.

[0042] In some implementation schemes, "gradual speed adjustment, followed by melting and extrusion casting" specifically includes the following steps:

[0043] Preheat the machine to 150-220℃ for the main unit and 180-220℃ for the die head, maintaining this temperature for 30-60 minutes. The main unit speed should be 200-400 rpm, and the main feeder speed 20-80 rpm. To prevent overload and shutdown, gradually increase the speed of the main feeder by 5-10 rpm each time. The auxiliary machine temperature should be 180-220℃, the auxiliary machine speed 100-300 rpm, and the auxiliary machine feeder speed 10-50 rpm.

[0044] Beneficial effects: The multilayer co-extruded bioreactor membrane material of the present invention has the following advantages:

[0045] (1) It has high heat-sealing performance, and the heat-sealing strength can reach more than 40N / 15mm;

[0046] (2) It has high transparency, reaching over 96%;

[0047] (3) It has good gas barrier properties, high puncture resistance, high tensile strength, and oxygen permeability of less than 0.1 mL / m2 .d.atm, water vapor transmission rate less than 0.4 mL / m 2 .d.atm.

[0048] (4) It has good biocompatibility and a cell culture density of 2.05 million / mL, which is suitable for HEK cell culture.

[0049] (5) No toxic substances or low molecular weight substances are released during sterilization. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of the multilayer co-extruded bioreactor membrane material in Example 1. Detailed Implementation

[0051] The present invention will be further described in detail below through embodiments.

[0052] Example 1

[0053] In the production of disposable bio-bag membrane materials, casting extrusion and blow molding are the most commonly used methods. For membrane materials with a thickness of less than 300μm, most are produced using co-extrusion blow molding, a simple process suitable for applications with less stringent requirements. For membrane materials used in disposable bioreactors, the requirements are more stringent. Compared to ordinary packaging films, their thickness is generally over 300μm. The manufacturing process employs a multi-layer co-extrusion casting method.

[0054] This embodiment uses multilayer co-extrusion to prepare a disposable bioreactor membrane material. The composition and structure of this membrane material include, for example, the following: Figure 1 The bag consists of a protective layer 1, an adhesive layer 2, a gas barrier layer 3, an adhesive layer 4, and a liquid contact layer 5. The liquid contact layer is composed of mPE / mPE:SiO2 and comprises an outer layer 51 and an inner layer 52. The tensile strength, transparency, oxygen permeability, water vapor permeability, and biocompatibility of the bag membrane material were investigated.

[0055] Example 2

[0056] This multilayer co-extruded bioreactor membrane material is manufactured using the following steps:

[0057] (1) Metallocene polyethylene and fumed silica were added to a mixer and stirred. The stirring speed was controlled at 1000 r / min and the stirring time was 3 min. The mass ratio of metallocene polyethylene to fumed silica was controlled at 4:6 to obtain a mixture. The mixture was added to an extruder. The extruder barrel temperature was controlled at 150℃ and the die temperature was controlled at 180℃. The temperature was maintained for 60 min. The main machine speed was 250 r / min. After hot melt extrusion and water cooling, the traction speed of the pelletizer was 90 m / min, thus obtaining the particles used to prepare the liquid contact layer.

[0058] (2) Heat each extruder to a temperature of 120°C and keep it heated for 30 minutes;

[0059] (3) Add each raw material to the corresponding feeder;

[0060] (4) Preheat the machine to 150℃ for the main unit and 180℃ for the die head, and maintain the temperature for 60 minutes. The main unit speed is 200 rpm, and the main unit feeding speed is 20 rpm. To prevent the main unit from overloading and shutting down, the main feeder speed is gradually increased by 5 rpm each time. The auxiliary machine temperature is 180℃, the auxiliary machine speed is 100 rpm, and the auxiliary machine feeding speed is 10 rpm, thereby obtaining the multilayer co-extruded bioreactor membrane material.

[0061] The multilayer co-extruded bioreactor membrane material includes:

[0062] The protective layer is made of linear low-density polyethylene and metallocene polyethylene, and the mass ratio of metallocene polyethylene to linear low-density polyethylene is controlled to be 1:9.

[0063] The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, preferably ethylene-vinyl acetate copolymer;

[0064] Gas barrier layer, the gas barrier layer is selected from polyvinyl alcohol;

[0065] The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, preferably ethylene-vinyl acetate copolymer;

[0066] The liquid contact layer comprises an outer layer and an inner layer. The outer layer is made of the particles used to prepare the liquid contact layer, and the inner layer is made of metallocene polyethylene.

[0067] Example 3

[0068] The preparation process of the multilayer co-extruded bioreactor membrane material is the same as in Example 2, except that the mass ratio of metallocene polyethylene to linear low-density polyethylene in the protective layer is changed to 2:8.

[0069] Example 4

[0070] The preparation process of the multilayer co-extruded bioreactor membrane material is the same as in Example 2, except that the mass ratio of metallocene polyethylene to linear low-density polyethylene in the protective layer is changed to 3:7.

[0071] Example 5

[0072] The preparation process of the multilayer co-extruded bioreactor membrane material is the same as in Example 2, except that the mass ratio of metallocene polyethylene to linear low-density polyethylene in the protective layer is changed to 4:6.

[0073] Example 6

[0074] The preparation process of this multilayer co-extruded bioreactor membrane is the same as in Example 2, except that the raw material ratio of the liquid contact layer particles is changed, and the mass ratio of metallocene polyethylene to fumed silica is changed to 5:5.

[0075] Example 7

[0076] The preparation process of the multilayer co-extruded bioreactor membrane material is the same as in Example 2, except that the raw material ratio of the liquid contact layer particles is changed, and the mass ratio of metallocene polyethylene to fumed silica is changed to 6:4.

[0077] Example 8

[0078] This multilayer co-extruded bioreactor membrane material is manufactured using the following steps:

[0079] (1) Metallocene polyethylene and fumed silica were added to a mixer and stirred. The stirring speed was controlled at 1000 r / min and the stirring time was 4 min. The mass ratio of metallocene polyethylene to fumed silica was controlled at 4:6 to obtain a mixture. The mixture was added to an extruder. The extruder barrel temperature was controlled at 180℃ and the die temperature was controlled at 200℃. The temperature was maintained for 45 min. The main machine speed was 350 r / min. After hot melt extrusion and water cooling, the traction speed of the pelletizer was 150 m / min, thus obtaining the particles used to prepare the liquid contact layer.

[0080] (2) Heat each extruder to a temperature of 180°C and keep it heated for 60 minutes;

[0081] (3) Add each raw material to the corresponding feeder;

[0082] (4) Preheat the machine to 180℃ for the main unit and 200℃ for the die head, and maintain the temperature for 45 minutes. The main unit speed is 300 rpm, and the main unit feeding speed is 50 rpm. To prevent the main unit from overloading and shutting down, the main feeder speed is gradually increased by 7 rpm each time. The auxiliary machine temperature is 200℃, the auxiliary machine speed is 200 rpm, and the auxiliary machine feeding speed is 30 rpm, thus obtaining the multilayer co-extruded bioreactor membrane material.

[0083] The multilayer co-extruded bioreactor membrane material includes:

[0084] The protective layer is made of linear low-density polyethylene and metallocene polyethylene, and the mass ratio of metallocene polyethylene to linear low-density polyethylene is controlled to be 1:9.

[0085] The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, preferably ethylene-vinyl acetate copolymer;

[0086] Gas barrier layer, the gas barrier layer is selected from polyvinyl alcohol;

[0087] The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, preferably ethylene-vinyl acetate copolymer;

[0088] The liquid contact layer comprises an outer layer and an inner layer. The outer layer is made of the particles used to prepare the liquid contact layer, and the inner layer is made of metallocene polyethylene.

[0089] Example 9

[0090] This multilayer co-extruded bioreactor membrane material is manufactured using the following steps:

[0091] (1) Metallocene polyethylene and fumed silica were added to a mixer and stirred. The stirring speed was controlled at 1000 r / min and the stirring time was 5 min. The mass ratio of metallocene polyethylene to fumed silica was controlled at 4:6 to obtain a mixture. The mixture was added to an extruder. The extruder barrel temperature was controlled at 200℃ and the die temperature was controlled at 220℃. The temperature was kept for 30 min. The main machine speed was 450 r / min. After hot melt extrusion and water cooling, the traction speed of the pelletizer was 225 m / min, thus obtaining the particles used to prepare the liquid contact layer.

[0092] (2) Heat each extruder to a temperature of 240°C and keep it heated for 90 minutes;

[0093] (3) Add each raw material to the corresponding feeder;

[0094] (4) Preheat the machine to 220℃, maintain the temperature of the main machine and the die head at 220℃ for 30 minutes, with the main machine speed at 400 rpm and the main machine feeding speed at 80 rpm. To prevent the main machine from overloading and shutting down, gradually increase the speed of the main feeder by 10 rpm each time. The auxiliary machine temperature is 220℃, the auxiliary machine speed is 300 rpm, and the auxiliary machine feeding speed is 50 rpm, thereby obtaining the multilayer co-extruded bioreactor membrane material.

[0095] The multilayer co-extruded bioreactor membrane material includes:

[0096] The protective layer is made of linear low-density polyethylene and metallocene polyethylene, and the mass ratio of metallocene polyethylene to linear low-density polyethylene is controlled to be 1:9.

[0097] The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, preferably ethylene-vinyl acetate copolymer;

[0098] Gas barrier layer, the gas barrier layer is selected from polyvinyl alcohol;

[0099] The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, preferably ethylene-vinyl acetate copolymer;

[0100] The liquid contact layer comprises an outer layer and an inner layer. The outer layer is made of the particles used to prepare the liquid contact layer, and the inner layer is made of metallocene polyethylene.

[0101] Specifically, the following substances can also replace fumed silica to improve cell growth rate: calcium phosphate (Ca3(PO4)2), calcium carbonate (CaCO3), calcium sulfate (CaSO4), and calcium silicate (CaSiO4). Furthermore, the preparation process for using these substances to replace fumed silica in the preparation of liquid contact layer particles and multilayer co-extruded bioreactor membrane materials is the same.

[0102] Comparative Example 1

[0103] The preparation process of this multilayer co-extruded bioreactor membrane material is the same as in Example 2, except that the raw material in the protective layer is changed to linear low-density polyethylene.

[0104] Comparative Example 2

[0105] The preparation process of this multilayer co-extruded bioreactor membrane material is the same as in Example 2, except that the raw material in the protective layer is changed to metallocene polyethylene.

[0106] Comparative Example 3

[0107] The preparation process of this multilayer co-extruded bioreactor membrane is the same as in Example 2, except that the composition of the liquid contact layer is changed. The liquid contact layer consists of only one layer made of metallocene polyethylene.

[0108] Performance testing

[0109] A. The tensile strength of the membrane material shall be tested in accordance with ASTM D882. The sample shall be made into a long strip shape as required and tested at a speed of 25 mm / min. 5 to 10 samples shall be prepared for each sample and the average value shall be calculated.

[0110] B. The transparency of the membrane material is tested according to ASTM D1003, using the haze meter method. The samples are tested for 40 hours in an environment with a temperature of 23℃±2℃ and a humidity of 50%±10%, according to the standard adjustment. There are 3 samples in each group.

[0111] C. The water vapor permeability of the membrane material is tested according to ASTM E96, using the weighing method, with 3 samples in each group, and the average value is calculated.

[0112] D. The oxygen permeability of the membrane material was tested according to ASTM D3985. The electrochemical method was used to test the membrane, and the average value was finally calculated.

[0113] E. The multi-layer co-extruded bioreactor membrane material is welded using an automatic frequency welding machine to form 5L disposable bioprocess bags, which are then sterilized by β-ray radiation. Biocompatibility testing is performed on the process bags by culturing HEK293 cells at an initial concentration of 100,000 cells / ml, at a temperature of 36.5℃±0.5℃, for 5-7 days, with a stirring speed of 200 rpm. Cell density is measured after the culture is complete.

[0114] 1. The effects of different protective layers on the performance of the membrane material of the multilayer co-extruded bioreactor were investigated. The specific results are shown in Table 1:

[0115] Table 1

[0116]

[0117] As shown in Table 1, different protective layers have a certain impact on the tensile strength, oxygen permeability, water vapor permeability, transparency and cell culture density of multilayer co-extruded bioreactor membranes.

[0118] The tensile strength, transparency, oxygen permeability, and cell culture effect of mPE and LLDPE as protective layers all meet the requirements for the preparation of disposable bioreactor membrane materials. However, when using a mixture of mPE and LLDPE, the tensile strength and weld strength are significantly better than those of comparative examples 1 and 2; therefore, a mixture of mPE and LLDPE is preferred as the protective layer.

[0119] 2. The effects of different liquid contact layers on the membrane material of the multilayer co-extruded bioreactor were investigated. The specific results are shown in Table 2:

[0120] Table 2

[0121]

[0122] As shown in Table 2, different liquid contact layers have a certain impact on the tensile strength, oxygen permeability, water vapor permeability, transparency and cell culture density of the multilayer co-extruded bioreactor membrane material, especially on the cell culture effect.

[0123] When using both inner and outer layers as the liquid contact layer, the tensile strength, oxygen permeability, water vapor permeability, and transparency of the prepared multilayer co-extruded bioreactor membrane are all suitable, and the cell culture density is significantly improved. This may be because fumed silica (SiO2) has better biocompatibility. However, when the content of fumed silica (SiO2) in the outermost layer is increased to 60%, the tensile strength and transparency decrease significantly. This indicates that the added SiO2 content is too high, affecting the physical properties. Under the condition of meeting the usage requirements, mPE / mPE:SiO2 is preferred as the liquid contact layer.

[0124] In summary, the multilayer co-extruded bioreactor membrane material of the present invention has the following advantages:

[0125] (1) It has high heat-sealing performance, and the heat-sealing strength can reach more than 40N / 15mm;

[0126] (2) It has high transparency, reaching over 96%;

[0127] (3) It has good gas barrier properties, high puncture resistance, high tensile strength, and oxygen permeability of less than 0.1 mL / m 2 .d.atm, water vapor transmission rate less than 0.4 mL / m 2 .d.atm.

[0128] (4) It has good biocompatibility and a cell culture density of 2.05 million / mL, which is suitable for HEK cell culture.

[0129] (5) No toxic substances or low molecular weight substances are released during sterilization.

[0130] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these should also be considered within the scope of protection of the invention.

Claims

1. A multilayer co-extruded bioreactor membrane material, including a liquid contact layer, characterized in that, A method for preparing particles for a liquid contact layer includes the following steps: Metallocene polyethylene and fumed silica were added separately to a mixer and stirred to obtain a mixture. The mixture is added to an extruder, the barrel temperature is controlled at 150-200℃, the die temperature is controlled at 180-220℃, and the temperature is maintained for 30-60 minutes. The main machine speed is 250-450 r / min. After hot melt extrusion and water cooling, the traction speed of the pelletizer is 90-225 m / min, thereby obtaining the particles used to prepare the liquid contact layer. The metallocene polyethylene has a mass content of 50-60%, and the fumed silica has a mass content of 40-50%.

2. The multilayer co-extruded bioreactor membrane material according to claim 1, characterized in that, Control the stirring speed to 1000 r / min and the stirring time to 3-5 min.

3. The multilayer co-extruded bioreactor membrane material according to claim 1, characterized in that, From the outside to the inside, it includes: A protective layer, wherein the protective layer is made of linear low-density polyethylene and metallocene polyethylene; The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer; A gas barrier layer, wherein the gas barrier layer is selected from polyvinyl alcohol; The adhesive layer is selected from any one of ethylene methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer; A liquid contact layer comprising an outer layer and an inner layer, the outer layer being made of particles for preparing a liquid contact layer as described in claim 1, and the inner layer being made of metallocene polyethylene.

4. The multilayer co-extruded bioreactor membrane material according to claim 3, characterized in that, From the outside to the inside, it includes: A protective layer, wherein the protective layer is made of linear low-density polyethylene and metallocene polyethylene; An adhesive layer, wherein the adhesive layer is selected from ethylene-vinyl acetate copolymer; A gas barrier layer, wherein the gas barrier layer is selected from polyvinyl alcohol; An adhesive layer, wherein the adhesive layer is selected from ethylene-vinyl acetate copolymer; A liquid contact layer comprising an outer layer and an inner layer, the outer layer being made of particles for preparing a liquid contact layer as described in claim 1, and the inner layer being made of metallocene polyethylene.

5. The multilayer co-extruded bioreactor membrane material according to claim 3, characterized in that, The thickness of the protective layer is 50-80 μm, and the mass content of metallocene polyethylene is controlled to be 10-40%, and the mass content of linear low-density polyethylene is controlled to be 60-90%.

6. The multilayer co-extruded bioreactor membrane material according to claim 3, characterized in that, The thickness of the adhesive layer is 10-18 μm.

7. The multilayer co-extruded bioreactor membrane material according to claim 3, characterized in that, The thickness of the gas barrier layer is 20-70 μm.

8. The multilayer co-extruded bioreactor membrane material according to claim 3, characterized in that, The thickness of the liquid contact layer is 150-250 μm; Among them, the specific surface area of ​​fumed silica is 100-400 m². 2 / g.

9. A method for preparing the multilayer co-extruded bioreactor membrane material according to any one of claims 1 to 8, characterized in that, Includes the following steps: Each extruder is heated to a temperature of 120-240℃ and held at that temperature for 30-90 minutes. Add each raw material to the corresponding feeder; By gradually adjusting the speed, the membrane material of the multilayer co-extruded bioreactor is obtained through melting, extrusion and casting.

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