A virus-removing membrane based on multi-component hydrogen bond network and its preparation method and application

Abstract

The application discloses a virus-removing membrane based on a multi-component hydrogen bond network and a preparation method and application thereof. The virus-removing membrane is prepared from a casting solution of a polysulfone family amphiphilic block copolymer, a hydrogen bond acceptor type solvent, a hydrogen bond donor type non-solvent and a bifunctional hydrogen bond non-solvent, and then immersed into a coagulation bath with a temperature greater than the cloud point of the casting solution to be solidified and formed. The virus-removing membrane based on the multi-component hydrogen bond network has a sponge-like gradient pore by improving the thermodynamic stability of the system and precisely controlling the hydrogen bond network. The average pore size of the prepared membrane is 15 nm-20 nm, which is obviously smaller than that of the prepared membrane in other RTIPS systems. The pore size is accurately controlled, the porosity is high and the connectivity is good, the pure water flux is high, the virus retention rate is high, the mechanical strength is excellent and the stability is good, and the virus-removing membrane is suitable for virus removal and protein purification of biological products.

Description

Technical Field

[0001] This invention relates to the field of polymer membrane materials and separation technology, and in particular to a virus removal membrane based on a multi-component hydrogen bond network, its preparation method, and its application. Background Technology

[0002] In the biopharmaceutical field, virus safety is the core lifeline of product quality. Virus filtration membranes, with their highly efficient physical retention capabilities, have become a key unit operation for ensuring the safety of biological products such as monoclonal antibodies and recombinant proteins. The pore size of these membranes needs to be approximately 15 nm-20 nm to accurately separate virus particles of similar size (e.g., parvovirus, 18-24 nm) from target antibody proteins (e.g., IgG, ~10 nm). Therefore, extreme requirements are placed on the membrane's pore size uniformity, surface hydrophilicity, and pore structure.

[0003] Currently, the mainstream methods for preparing polymer porous membranes via phase inversion are non-solvent-induced phase separation (NIPS) and thermally induced phase separation (TIPS). The NIPS process is simple, but the phase separation process is intense and instantaneous, easily forming a dense skin layer and finger-like macropore structures. The presence of concentration polarization is detrimental to the permeation of target proteins within the finger-like pores, and the presence of an excessively thin, dense layer also poses a risk of viral leakage. The traditional TIPS method can obtain a more uniform pore structure, but it requires extremely high processing temperatures and specific diluents, resulting in high energy consumption and limited material selection.

[0004] Reverse thermally induced phase separation (RTIPS) is an improved technique that exhibits unique potential. It utilizes a casting solution system with a "low critical eutectic temperature (LCST)" characteristic: a homogeneous, clear solution at room temperature, but a heterogeneous solution above its cloud point. When immersed in a coagulation bath at a temperature above its cloud point, thermally induced phase separation due to temperature rise and solvent-induced phase separation due to solvent intrusion occur simultaneously, resulting in film solidification through both phase transformation mechanisms. Theoretically, the TIPS phase transformation is advantageous for preparing sponge-like porous membranes, while the NIPS phase transformation method is simpler and has lower energy consumption.

[0005] While RTIPS (Reverse Interfiltration and Photofiltration) promises to produce sponge-like membranes with high porosity and good permeability, thus combining high flux with excellent mechanical properties, RTIPS technology faces fundamental technical limitations when applied to high-end applications such as virus filtration. For example, existing RTIPS research and patents (e.g., US10118133B2, CN103055724B) primarily focus on the preparation of microfiltration and macroporous ultrafiltration membranes. To obtain a stable LCST (Liquid Crystallization-Stage Transmission) system, formulations often rely on a high proportion of small-molecule non-solvents (such as alcohols and polyols), resulting in large polymer-depleted phase regions during phase separation. Consequently, the final membrane pore size is generally much larger than 20 nm, even reaching the micrometer scale, failing to meet the nanometer-scale (20 nm) precision required for virus retention. However, obtaining a small-pore membrane means that the polymer solid content must be increased in order to obtain a denser membrane; but in the traditional RTIPS system, increasing the solid content often leads to a sharp increase in viscosity and a decrease in thermodynamic stability, and the cloud point temperature also decreases until the system is unstable at room temperature and cannot be used to form a membrane. Therefore, there is an inherent contradiction between high solid content and the RTIPS process.

[0006] Furthermore, to improve the hydrophilicity of the membrane, hydrophilic polymers (such as PVP and PEG) are typically added. However, in RTIPS systems, the introduction of these additives significantly alters the phase diagram and thermodynamic stability of the system, leading to a decrease in cloud point or disruption of solution homogeneity. More seriously, physically blended additives pose a leaching risk during long-term use, affecting product safety and performance stability. Therefore, there is a trade-off between hydrophilic modification and system stability.

[0007] Based on this, existing technologies lack a molecular design and preparation strategy that can stably achieve RTIPS phase transformation at high polymer solid content and precisely control the final membrane pore size to the nanoscale. This is also a technical barrier that the RTIPS method cannot overcome in its transition from macroporous membranes to precision virus / antibody separation membranes. Summary of the Invention

[0008] The purpose of this invention is to provide a method for preparing a virus-removing membrane based on a multi-component hydrogen bond network, which solves the above-mentioned technical problems and employs reverse thermal phase separation.

[0009] Another objective of this invention is to develop a virus-removing membrane with nanoscale fine pores based on a multi-component hydrogen bond network, prepared by the above-described method, and its application in scenarios such as virus removal and protein purification in biological products.

[0010] Therefore, the technical solution of the present invention is as follows:

[0011] A virus-removing membrane based on a multi-component hydrogen bond network is formed by casting a liquid film prepared from a polysulfone amphiphilic block copolymer, a hydrogen bond acceptor solvent, a hydrogen bond donor non-solvent, and a bifunctional hydrogen bond non-solvent, and then immersing it in a coagulation bath at a temperature higher than the cloud point of the casting liquid to solidify it. The prepared membrane has a sponge-like gradient pore with an average pore size cutoff of 15 nm-20 nm.

[0012] In terms of structure, the hydrophobic segments of polysulfone amphiphilic block copolymers are selected from polyethersulfone and polysulfone, and the hydrophilic segments are selected from polyethylene glycol, polyethyleneimine, polydioxazoline, and β-cyclodextrin.

[0013] Preferably, the polysulfone amphiphilic block copolymer can be selected from, but is not limited to: polyethersulfone-intercalated polyethylene glycol block copolymer (PES-b-PEG), polyethersulfone-intercalated β-cyclodextrin block copolymer (PES-b-β-CD), polyethersulfone-intercalated polyethyleneimine (PES-b-PEI), polysulfone-intercalated polyethyleneimine block copolymer (PSf-b-PEI), polysulfone-intercalated β-cyclodextrin block copolymer (PSf-b-β-CD), and polysulfone-intercalated polyethylene glycol block copolymer (PSf-b-PEG).

[0014] Preferably, the hydrophilic segments in the polysulfone amphiphilic block copolymer account for 3%-25% by mass and have a number average molecular weight of 20,000-50,000 Da.

[0015] In this invention, the polysulfone amphiphilic block copolymer exhibits good film-forming properties and ensures good mechanical strength by limiting its number-average molecular weight. Simultaneously, by limiting the proportion of its hydrophilic segments, hydrophilic modification of the membrane structure is achieved. Since the hydrophilic structure of the membrane is chemically bonded to the polymer backbone, it can be fixed within the polymer network after film formation. Unlike physically blended additives, it avoids the problem of hydrophilic additive dissolution, resulting in durable and stable performance.

[0016] In some embodiments of the present invention, when the mass percentage of hydrophilic segments in the polysulfone amphiphilic block copolymer is less than 3%, it is insufficient to achieve hydrophilic modification of the nanoscale virus removal membrane; while when the mass percentage of hydrophilic segments in the polysulfone amphiphilic block copolymer exceeds 25%, the mechanical strength of the nanoscale virus removal membrane decreases significantly due to the gradual increase in the proportion of hydrophilic segments, and it cannot form a film.

[0017] In other embodiments of the present invention, when the number average molecular weight of the polysulfone amphiphilic block copolymer is lower than the above-mentioned limit range, the nano-virus removal membrane cannot be formed; while when the molecular weight of the polysulfone amphiphilic block copolymer is too high, although it helps to improve the film-forming properties and mechanical strength of the membrane, it is not easy to perform fine pore size control, and the separation effect of virus and protein is poor.

[0018] The casting solution is preferably composed of 18%-30% polysulfone amphiphilic block copolymer, 20%-50% hydrogen bond acceptor solvent, 5%-25% hydrogen bond donor non-solvent, and 10%-40% bifunctional hydrogen bond non-solvent by mass fraction.

[0019] Hydrogen bond acceptor solvents are small molecule solvents whose molecular structure contains at least one hydrogen bond acceptor group; hydrogen bond donor nonsolvents are small molecule solvents or oligomer solvents whose molecular structure contains at least two hydrogen bond donor groups; bifunctional hydrogen bond nonsolvents are solvents whose molecular structure contains at least two hydrogen bond donor groups and at least one hydrogen bond acceptor group; the hydrogen bond acceptor group is selected from ether, carbonyl, sulfoxide, and amino groups, and the hydrogen bond donor group is selected from hydroxyl groups.

[0020] Preferably, the hydrogen bond acceptor solvent is selected from, but not limited to, N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide.

[0021] Preferably, the hydrogen bond donor non-solvent is selected from, but not limited to, glycerol, ethylene glycol, 1,3-propanediol, and polyethylene glycol (number average molecular weight range of 200 Da-400 Da).

[0022] Preferably, the bifunctional hydrogen-bonded nonsolvent is selected from, but not limited to, diethylene glycol, triethylene glycol, diethanolamine, and triethanolamine.

[0023] The casting solution formulated using the above-mentioned method contains a polysulfone amphiphilic block copolymer uniformly dispersed in a multi-component system composed of hydrogen bond donor-type nonsolvents, hydrogen bond acceptor-type nonsolvents, and bifunctional hydrogen bond nonsolvents. The hydrophilic segments of the polysulfone amphiphilic block copolymer (such as PEG and PEI) serve as fixed, high-density hydrogen bond sites within a special hydrogen bond network, forming a strong and stable multi-component hydrogen bond network with the other components. This ultimately results in a dynamically reversible special hydrogen bond network in the casting solution system, acting as the core hub for regulating the entire RTIPS process. The characteristics of this casting solution system are: stable maintenance of a homogeneous and clear state of high-solids content casting solution at low temperatures, and a specific low critical eutectic temperature, i.e., a cloud point; the cloud point of this casting solution system is within the range of 40 ℃ to 80 ℃.

[0024] The special hydrogen bond network in this casting solution system can efficiently "bind" and accommodate a high proportion of block copolymers and non-solvents at low temperatures. This allows the casting solution to maintain uniformity, clarity, and suitable processing fluidity at room temperature even when the polymer solid content is high. The cloud point is precisely controlled within the moderate low temperature range described above, laying the material foundation for obtaining small pore sizes in the future.

[0025] The preparation steps of the virus-removing membrane based on a multi-component hydrogen bond network are as follows:

[0026] S1. Preparation of polysulfone amphiphilic block copolymers suitable for preparing nano-virus-removing membranes;

[0027] S2. Mix the polysulfone amphiphilic block copolymer, hydrogen bond acceptor solvent, hydrogen bond donor non-solvent and bifunctional hydrogen bond non-solvent, and stir at 20 ℃-50 ℃ until a homogeneous and clear homogeneous casting solution is obtained.

[0028] S3. The casting solution prepared in step S2 is scraped or spun to form a liquid film, and immediately immersed in a coagulation bath with a temperature higher than the cloud point of the casting solution, so that the liquid film undergoes rapid thermal phase separation and non-solvent-induced phase separation, and solidifies into a film.

[0029] Preferably, in step S3, the film-forming environment temperature of the liquid film is 25 °C and the humidity is 30%.

[0030] Preferably, in step S3, the thickness of the liquid film is 150 μm-250 μm, so as to control the thickness of the virus removal membrane to be 120 μm-180 μm.

[0031] Preferably, in step S3, the temperature of the coagulation bath is 5 ℃-20 ℃ higher than the turbidity point of the casting liquid; in actual operation, the liquid film can be observed to undergo rapid phase transformation and solidify in the coagulation bath.

[0032] Preferably, in step S3, the coagulation bath is pure water or a mixed solution prepared from a good solvent and pure water; wherein, the good solvent in the mixed solution may be, but is not limited to, N,N-dimethylacetamide or N-methylpyrrolidone, with a mass fraction ≤70%.

[0033] Preferably, the membrane solidified in the coagulation bath is subjected to water washing treatment. Specifically, after the membrane automatically detaches, it is immersed in deionized water for 48 hours, and the deionized water is replaced every 4 hours to wash away residual solvent in the membrane, and finally a nano-virus-removing membrane is prepared.

[0034] In the preparation process of the virus-removing membrane based on the multi-component hydrogen-bonded network, when the liquid membrane is immersed in a coagulation bath above the cloud point of the casting solution, thermal motion weakens the hydrogen-bonded network, resulting in a RTIPS phase transition. At this time, the phase separation process is driven by two synergistic factors: on the one hand, the temperature above the cloud point causes the casting solution to undergo a TIPS phase transition; on the other hand, the intrusion of non-solvents causes the casting solution to undergo a NIPS phase transition. Furthermore, since heat transfer is faster than mass transfer, a large number of depleted phase nuclei appear inside the casting solution due to the TIPS phase transition immediately after the phase transition. These depleted phase nuclei will rapidly become membrane pores during the subsequent NIPS phase transition, thereby reducing the difference in phase transition rate at different locations during the phase transition and making the membrane exhibit a relatively uniform sponge-like pore structure. Due to the high solids content of the casting solution and the hydrogen bonding between the hydrophilic segments in the block copolymer and the solvent in the casting solution, the size of the depleted phase nuclei generated by TIPS is limited to a small range, resulting in a small pore size in the final membrane retaining layer. That is, the "synergistic phase separation" effect guides the formation of nanoscale pores.

[0035] Subsequently, after the phase inversion is completed, the hydrophilic segments are permanently and in situ fixed to the membrane skeleton and the inner surface of the pores as the polymer-rich phase solidifies. This not only achieves the long-lasting hydrophilicity of the membrane body and avoids the leaching risk of physically blended additives, but also ensures that the hydrophilic surface can effectively inhibit protein adsorption, guaranteeing high throughput and high protein recovery rate under long-term operation. In other words, the "in-situ fixation" effect ensures long-lasting high performance.

[0036] An application of a virus removal membrane based on a multi-component hydrogen bond network, which combines high water flux, high virus rejection rate, persistent hydrophilicity and excellent mechanical strength, is suitable for virus removal and protein purification in the field of biopharmaceuticals, such as, but not limited to, the separation of viruses and proteins in the biopharmaceutical field.

[0037] Compared with existing technologies, the beneficial effects of the virus-removing membrane based on a multi-component hydrogen bond network prepared by the method of this invention include:

[0038] (1) Accurate pore size control: By applying block copolymers and multi-component hydrogen bond networks to the RTIPS method to prepare virus-removing membranes, thanks to the improved thermodynamic stability of the system and the precise control of the hydrogen bond network, the average pore size of the prepared membrane is 15nm-20nm, which is significantly smaller than the pore size of membranes prepared in other RTIPS systems. The virus rejection rate is high (LRV≥ 4.5), meeting the requirements of virus-removing membranes.

[0039] (2) High performance: The membrane structure is a typical sponge-like pore with high porosity and good permeability. The pure water flux is significantly higher than that of the NIPS virus removal membrane of the same level, while also having excellent mechanical strength.

[0040] (3) Stability: The hydrophilicity comes from the chemical structure modification, and there is no problem of hydrophilic additives dissolving, so the performance is long-lasting and stable;

[0041] (4) Strong controllability: By adjusting the type of block copolymer and the formation of multi-component hydrogen bond network, the cloud point, phase separation kinetics and final membrane pore size of the casting solution can be systematically controlled. The process window is wide, the repeatability is good, and it is easy to scale up production. Attached Figure Description

[0042] Figure 1 The cross-sectional view of the virus-removing membrane based on a multi-component hydrogen bond network prepared in Example 1 of the present invention is magnified by 500×.

[0043] Figure 2 The image shows the upper surface of the virus-removing membrane based on a multi-component hydrogen bond network prepared in Example 1 of this invention, with a magnification of 80k×.

[0044] Figure 3 The image shows the lower surface of the virus-removing membrane based on a multi-component hydrogen bond network prepared in Example 1 of this invention, with a magnification of 5k×.

[0045] Figure 4 This is a particle size distribution diagram of IgG protein and virus (SM2 bacteriophage) in the test of an embodiment of the present invention;

[0046] Figure 5 The graphs show the contact angle test results of the virus-removing membranes based on multi-component hydrogen bond networks prepared in Examples 1-3 and Comparative Examples 1-3 of this invention. Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention.

[0048] Example 1

[0049] A virus-removing membrane based on a multi-component hydrogen bond network is prepared by the following steps:

[0050] S1. Referring to the published patent CN115873259A, PES-b-PEG was prepared with a number-average molecular weight of 38,000 and a PEG segment mass fraction of 18% in the block copolymer;

[0051] S2. 25 wt.% of PES-b-PEG, 35 wt.% of N-methylpyrrolidone (NMP, hydrogen bond acceptor solvent), 15 wt.% of polyethylene glycol 400 (PEG400, hydrogen bond donor non-solvent) and 25 wt.% of triethylene glycol (TEG, bifunctional hydrogen bond non-solvent) were mixed and stirred at 40 °C for 12 h to form a homogeneous and clear casting solution. The cloud point was measured to be 58 °C.

[0052] S3. At 25 ℃ and 30% humidity, pour the casting solution onto a clean glass plate and scrape it into a liquid film using a 250 μm scraper. Then immerse it in a pure water coagulation bath at 65 ℃. The liquid film will undergo phase transformation and solidify rapidly in the coagulation bath.

[0053] S4. After the membrane automatically detaches, immerse the membrane in deionized water for 48 hours, and replace the deionized water every 4 hours to remove residual solvent, and finally prepare a nanoscale virus-removing membrane.

[0054] Example 2

[0055] A virus-removing membrane based on a multi-component hydrogen bond network is prepared by the following steps:

[0056] S1. Referring to the published patent CN120059198A, PSf-b-PEI was prepared with a number-average molecular weight of 45,000 and a PEI segment mass fraction of 15% in the block copolymer;

[0057] S2. 22 wt.% PSf-b-PEI, 39 wt.% N,N-dimethylacetamide (DMAc, hydrogen bond acceptor solvent), 5 wt.% glycerol (hydrogen bond donor non-solvent) and 34 wt.% diethylene glycol (DEG, bifunctional hydrogen bond non-solvent) were mixed and stirred at 35 °C for 15 h to form a homogeneous and clear casting solution. The cloud point was measured to be 52 °C.

[0058] S3. At 25 ℃ and 35% humidity, pour the casting solution onto a clean glass plate and use a 200 μm scraper to scrape it into a liquid film. Then immerse it in a pure water coagulation bath at 70 ℃. The liquid film will undergo phase transformation and solidify rapidly in the coagulation bath.

[0059] S4. After the membrane automatically detaches, immerse the membrane in deionized water for 48 hours, and replace the deionized water every 4 hours to remove residual solvent, and finally prepare a nanoscale virus-removing membrane.

[0060] Example 3

[0061] A virus-removing membrane based on a multi-component hydrogen bond network is prepared by the following steps:

[0062] S1. Referring to the published patent CN117384385A, PES-b-β-CD was prepared with a number-average molecular weight of 42,000 and a mass fraction of β-CD segments in the block copolymer of 5%.

[0063] S2. 24 wt.% of PES-b-β-CD, 40 wt.% of N,N-dimethylformamide (DMF, hydrogen bond acceptor solvent), 8 wt.% of 1,3-propanediol (hydrogen bond donor non-solvent) and 28 wt.% of triethanolamine (bifunctional hydrogen bond non-solvent) were mixed and stirred at 45 °C for 20 h to form a high-viscosity but homogeneous and clear casting solution with a cloud point of 62 °C.

[0064] S3. At 25 ℃ and 35% humidity, pour the casting solution onto a clean glass plate and use a 200 μm scraper to scrape it into a liquid film. Then immerse it in a pure water coagulation bath at 80 ℃. The liquid film will undergo phase transformation and solidify rapidly in the coagulation bath.

[0065] S4. After the membrane automatically detaches, immerse the membrane in deionized water for 48 hours, and replace the deionized water every 4 hours to remove residual solvent, and finally prepare a nanoscale virus-removing membrane.

[0066] Comparative Example 1

[0067] A nanoscale virus-removing membrane differs from Example 1 in that: in step S3, the casting solution is poured onto a clean glass plate at 25 ℃ and 30% humidity, and a liquid film is formed by scraping with a 250 μm scraper. The film is then immersed in a pure water coagulation bath at 25 ℃, and the liquid film solidifies in the coagulation bath.

[0068] Comparative Example 2

[0069] A nanoscale virus-removing membrane differs from Example 1 in that: in step S2, 25 wt.% of PES-b-PEG, 47.5 wt.% of N-methylpyrrolidone (NMP, hydrogen bond acceptor type solvent) and 27.5 wt.% of polyethylene glycol 400 (PEG400, hydrogen bond donor type non-solvent) are mixed and stirred at 40 °C for 12 h to form a homogeneous and clear casting solution, with a cloud point of 47 °C.

[0070] Comparative Example 3

[0071] A nanoscale virus-removing membrane differs from Example 1 in that: in step S2, 25 wt.% of PES-b-PEG, 42.5 wt.% of N-methylpyrrolidone (NMP, hydrogen bond acceptor solvent) and 32.5 wt.% of triethylene glycol (TEG, bifunctional hydrogen bond non-solvent) are mixed and stirred at 40 °C for 12 h to form a homogeneous and clear casting solution with a cloud point of 55 °C.

[0072] Comparative Example 4

[0073] A nanoscale virus-removing membrane differs from Example 1 in that, in step S2, the casting solution formulation is changed to a mixture of 25 wt.% PES-b-PEG, 32.5 wt.% polyethylene glycol 400 (PEG400, hydrogen bond donor type non-solvent), and 42.5 wt.% triethylene glycol (TEG, bifunctional hydrogen bond non-solvent). However, in this new casting solution formulation, the block copolymer PES-b-PEG cannot be completely dissolved, making it impossible to prepare a homogeneous casting solution and further form a film.

[0074] Performance testing:

[0075] (a) Characterization of the microscopic properties of the membrane:

[0076] like Figure 1 The image shown is a cross-sectional view of the virus-removing membrane based on a multi-component hydrogen bond network prepared in Example 1 of the present invention, with a magnification of 500. Figure 2 The image shown is a SEM image of the upper surface of the virus-removing membrane based on a multi-component hydrogen bond network prepared in Example 1 of the present invention, with a magnification of 5k×. Figure 3 The image shown is a SEM image of the lower surface of the virus-removing membrane based on a multi-component hydrogen bond network prepared in Example 1 of the present invention, with a magnification of 80k×.

[0077] Combination Figures 1-3 It can be determined that the virus-removing membrane based on a multi-component hydrogen-bonded network prepared in Example 1 has a sponge-like porous structure in its cross-section. Uniformly distributed pores can be observed on both the upper and lower surfaces, and there is a significant difference in pore size between the upper and lower surfaces. Testing revealed that the pore size range on the upper surface of this virus-removing membrane based on a multi-component hydrogen-bonded network is 100 nm-700 nm, and the pore size range on the lower surface is 15 nm-30 nm, giving the virus-removing membrane a unique sponge-like gradient pore structure. Similarly, the virus-removing membranes based on multi-component hydrogen-bonded networks prepared in Examples 2 and 3 also possess the same structural characteristics.

[0078] The pore size of the virus-removing membranes based on multi-component hydrogen bond networks prepared in Examples 1-3 and the nanoscale virus-removing membranes prepared in Comparative Examples 1-3 were tested using gas-liquid or liquid-liquid capillary flow pore size testing methods. The specific test results are shown in Table 1 below.

[0079] Table 1:

[0080]

[0081] As can be seen from the test results in Table 1, the virus-removing membranes based on multi-component hydrogen bond networks prepared in Examples 1-3 have a pore size of 18 nm-20 nm. The nanoscale virus-removing membrane prepared in Comparative Example 1, which did not undergo RTIPS phase transformation but only NIPS phase transformation, has smaller pores and a finger-like pore structure in cross-section. The pore size of the nanoscale virus-removing membranes prepared in Comparative Examples 2 and 3 is significantly larger, ranging from 45 nm to 55 nm, and cannot effectively retain viruses.

[0082] (II) Virus Filtration Performance Test:

[0083] The filtration performance of the virus-removing membranes based on multi-component hydrogen bond networks prepared in Examples 1-3 and the nanoscale virus-removing membranes prepared in Comparative Examples 1-3 were tested, including pure water permeability testing, 1 g / L IgG protein permeability testing, and virus rejection rate. The method for testing the 1 g / L IgG protein permeability can refer to the test steps in the national recommended standard GB / T 323602015. The method for determining the virus rejection rate can refer to the published patent CN1759924B.

[0084] The test results are shown in Table 2 below.

[0085] Table 2:

[0086]

[0087] As can be seen from the test results in Table 2, the virus rejection rate of the virus-removing membranes based on multi-component hydrogen bond networks prepared in Examples 1-3 is 6.2 LRV-6.6 LRV, meeting the requirement of a virus rejection rate >6 log+; the IgG protein permeability is 98.9%-99.5%, meeting the requirement of an IgG protein permeability >6 log+; at the same time, the pure water permeability coefficient of the virus-removing membrane based on multi-component hydrogen bond networks is 586 LMH / bar-650 LMH / bar, confirming that the virus-removing membrane based on multi-component hydrogen bond networks prepared by the method of the present invention has good pure water permeability. In contrast, the three nanoscale virus-removing membranes prepared in Comparative Examples 1-3 show significantly reduced performance in both pure water permeability coefficient and virus rejection rate, or have one aspect of performance that is too low, failing to meet the requirements for virus-removing membranes.

[0088] like Figure 4 The figure shows the particle size distribution of IgG protein and virus (MS2 phage) in this test; the average particle size of IgG protein is approximately 9 nm, and the average particle size of virus is approximately 33 nm. (See Table 1 and...) Figure 4 It can be inferred that the average pore size of the virus-removing membrane based on the multi-component hydrogen bond network prepared in the above embodiments is about 20 nm, which is consistent with the pore size of 15 nm-20 nm obtained in the above tests. At the same time, due to its good hydrophilicity, it can effectively separate IgG protein and virus (MS2 bacteriophage) efficiently.

[0089] (III) Mechanical property testing:

[0090] The mechanical properties of the virus-removing membranes based on multi-component hydrogen bond networks prepared in Examples 1-3 and the nanoscale virus-removing membranes prepared in Comparative Examples 1-4 were tested. The specific test results are shown in Table 3 below.

[0091] Table 3:

[0092]

[0093] As can be seen from the test results in Table 3, the virus-removing membranes based on multi-component hydrogen bond networks prepared in Examples 1-3 have a tensile strength ≥7.4 MPa and an elongation at break ≥37%, which meets the application requirements of virus-removing membranes based on multi-component hydrogen bond networks. However, the nanoscale virus-removing membranes prepared in Comparative Examples 1-3 exhibit poor tensile strength and / or elongation at break because their molecular structures lack a strong and stable special multiple hydrogen bond network.

[0094] (iv) Hydrophilicity test:

[0095] The hydrophilicity of the virus-removing membranes based on multi-component hydrogen-bonded networks prepared in Examples 1-3 and the nanoscale virus-removing membranes prepared in Comparative Examples 1-3 were tested. Specific test results are as follows: Figure 5 As shown. From Figure 5 As can be seen, the water contact angles of the virus-removing membranes based on multi-component hydrogen-bonded networks prepared in Examples 1-3 are significantly lower than those in the comparative examples. Among them, the virus-removing membrane based on multi-component hydrogen-bonded networks in Example 1 exhibits the best hydrophilicity. For Comparative Examples 1-3, Comparative Example 1, prepared solely through NIPS phase inversion without undergoing RTIPS phase inversion, exhibits the worst hydrophilicity. While Comparative Examples 2 and 3 use RTIPS phase inversion, their hydrophilicity is better than Comparative Example 1 but worse than Examples 1-3 because the casting solution only employs a binary hydrogen-bonded network. Therefore, based on the above hydrophilicity tests, it is demonstrated that the hydrophilicity of the virus-removing membrane prepared using the present invention based on multi-component hydrogen-bonded networks and block copolymers, and using the RTIPS phase inversion method, is significantly improved.

Claims

1. A method for preparing a virus-removing membrane based on a multi-component hydrogen-bonded network, characterized in that, It is formed by immersing a casting solution, which is prepared from a polysulfone amphiphilic block copolymer, a hydrogen bond acceptor solvent, a hydrogen bond donor non-solvent, and a bifunctional hydrogen bond non-solvent, into a coagulation bath at a temperature higher than the cloud point of the casting solution to solidify.

2. The method for preparing a virus-removing membrane based on a multi-component hydrogen bond network according to claim 1, characterized in that, The number average molecular weight of polysulfone amphiphilic block copolymers is 20,000 Da-50,000 Da, and the mass fraction of their hydrophilic segments is 3%-25%.

3. The method for preparing a virus-removing membrane based on a multi-component hydrogen bond network according to claim 2, characterized in that, The polysulfone amphiphilic block copolymers are selected from polyethersulfone-intercalated-polyethylene glycol block copolymers, polyethersulfone-intercalated-β-cyclodextrin block copolymers, polyethersulfone-intercalated-polyethyleneimine, polysulfone-intercalated-polyethyleneimine block copolymers, polysulfone-intercalated-β-cyclodextrin block copolymers, and polysulfone-intercalated-polyethylene glycol block copolymers.

4. The method for preparing a virus-removing membrane based on a multi-component hydrogen bond network according to claim 1, characterized in that, The casting solution consists of 18%-30% polysulfone amphiphilic block copolymer, 20%-50% hydrogen bond acceptor solvent, 5%-25% hydrogen bond donor non-solvent, and 10%-40% bifunctional hydrogen bond non-solvent by mass fraction.

5. The method for preparing a virus-removing membrane based on a multi-component hydrogen bond network according to claim 1, characterized in that, Hydrogen bond acceptor solvents are small molecule solvents whose molecular structure contains at least one hydrogen bond acceptor group; hydrogen bond donor nonsolvents are small molecule solvents or oligomer solvents whose molecular structure contains at least two hydrogen bond donor groups; bifunctional hydrogen bond nonsolvents are solvents whose molecular structure contains at least two hydrogen bond donor groups and at least one hydrogen bond acceptor group; wherein, the hydrogen bond acceptor group is an ether group, carbonyl group, sulfoxide group, or amino group, and the hydrogen bond donor group is a hydroxyl group.

6. The method for preparing a virus-removing membrane based on a multi-component hydrogen bond network according to claim 5, characterized in that, Hydrogen bond acceptor solvents are selected from N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide; hydrogen bond donor non-solvents are selected from polyethylene glycol, glycerol, ethylene glycol, and 1,3-propanediol; and bifunctional hydrogen bond non-solvents are selected from diethylene glycol, triethylene glycol, diethanolamine, and triethanolamine.

7. The method for preparing a virus-removing membrane based on a multi-component hydrogen bond network according to claim 1, characterized in that, The casting solution is formed by mixing a polysulfone amphiphilic block copolymer, a hydrogen bond acceptor solvent, a hydrogen bond donor non-solvent, and a bifunctional hydrogen bond non-solvent, and stirring at 20 ℃-50 ℃ until homogeneous and clear. Then, a liquid film is formed by scraping or spinning based on the casting solution, and immediately immersed in a coagulation bath at a temperature higher than the cloud point of the casting solution.

8. The method for preparing a virus-removing membrane based on a multi-component hydrogen bond network according to claim 7, characterized in that, The coagulation bath uses pure water or a mixed solution prepared from a good solvent and pure water; wherein, the good solvent in the mixed solution may be, but is not limited to, N,N-dimethylacetamide or N-methylpyrrolidone, with a mass fraction ≤70%; the temperature of the coagulation bath is 5℃-20℃ higher than the cloud point of the casting solution.

9. A virus-removing membrane based on a multi-component hydrogen bond network, characterized in that, Prepared by the preparation method according to any one of claims 1-8, it has a sponge-like gradient pore with an average pore size of 15 nm-20 nm.

10. A method for preparing a virus-removing membrane based on a multi-component hydrogen bond network according to claim 9, characterized in that, Used for the separation of viruses and proteins in the biological field.

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