Nylon 6 nanofiber virus-removing filtering membrane as well as preparation method and application thereof

Abstract

The invention provides a nylon 6 nanofiber virus-removing filtering membrane and a preparation method and application thereof.The nylon 6 nanofiber virus-removing filtering membrane comprises a base material and a nylon 6 nanofiber membrane compounded to the surface of the base material, the average pore size of the virus-removing filtering membrane is 20 nm, the virus-removing filtering membrane plays a role in blocking parvoviruses, the surface of the virus-removing filtering membrane is charged, and the surface of the virus-removing filtering membrane is not prone to being damaged. Proteins with the same charges on the surface can be prevented from adhering to the surface of the fiber. In the preparation process of the virus-removing filtering membrane, the nylon 6 nanofibers with a certain diameter range are selected and compounded on the surface of the base material in a stable dispersion state, the uniform microporous virus-removing filtering membrane is prepared, the effect that parvoviruses are blocked and protein molecules are not easily intercepted is achieved, the hydrophilicity of the nylon 6 nanofibers is relatively good, and the virus-removing filtering membrane has a good application prospect. The non-specific adsorption of the filtering membrane on the protein is reduced; the nylon 6 nanofiber virus-removing filtering membrane can be applied to the field of biological medicine products, and has important significance on separation and purification of biological preparations.

Description

Technical Field

[0001] This invention relates to the field of filter membrane material technology, and in particular to a nylon 6 nanofiber virus-removing filter membrane, its preparation method and application. Background Technology

[0002] With the development of technology, biological pharmaceuticals are widely used due to their good therapeutic effects and few side effects. Antibody macromolecules in biological preparations are mostly produced from biological organisms such as animal cells. Therefore, to ensure the safety and efficacy of the drugs, it is necessary to separate and purify the fluids containing antibody macromolecules, especially to remove various small viruses, the smallest of which, mouse parvovirus, is approximately 20 nm in size. Furthermore, the production process of various biological preparations is extremely complex, requiring a series of steps including cultivation, purification, cleaning, passivation, extraction, freezing, and lyophilization. It is difficult to avoid introducing various viruses during these processes. If these viruses are injected into patients along with the biological preparations, the consequences could be disastrous.

[0003] Currently, membrane separation technology is the most commonly used method for removing viruses from fluids. Using a separation membrane as its core, and driven by external pressure or concentration differences, it can separate, concentrate, and purify components in a feed solution. Compared to conventional separation technologies, membrane separation technology offers higher separation efficiency, requires no external reagents, and can separate systems that conventional technologies cannot. For example, a Chinese invention patent (application publication number CN113842792A) discloses an asymmetric PES filter membrane for virus removal and its preparation method. This PES filter membrane comprises a main body with non-directional tortuous pathways. One side surface of the main body is a first outer surface with an average pore size of 150-450 nm, constituting a macroporous membrane. The other side surface of the main body is a second outer surface with an average pore size of 10-42 nm, constituting a microporous membrane. The average pore size of the main body changes continuously in a gradient from the region near the first outer surface to the region near the second outer surface. The main body includes a pre-filtration layer and a separation layer for virus interception, with continuous fibers forming a transition between the other side of the pre-filtration layer and the other side of the separation layer. However, the PES material in this filter membrane has poor hydrophilicity, which affects protein yield, leading to material waste and increased virus removal filtration costs.

[0004] In view of this, it is necessary to design an improved nylon 6 nanofiber virus-removing filter membrane, its preparation method and application, in order to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a nylon 6 nanofiber antiviral filter membrane, its preparation method and application. By selecting nylon 6 nanofibers within a certain diameter range and composite them in a stable dispersed state on the surface of a substrate, an antiviral filter membrane with an average pore size of 20 nm is obtained, which can block small viruses and is of great significance for the separation and purification of biological agents.

[0006] To achieve the above-mentioned objective, the present invention provides a nylon 6 nanofiber virus-removing filter membrane, comprising a substrate and a nylon 6 nanofiber membrane composited on the surface of the substrate, wherein the average pore size of the virus-removing filter membrane is 20 nm and the surface of the virus-removing filter membrane is charged.

[0007] As a further improvement of the present invention, the nylon 6 nanofiber membrane is composed of nylon 6 nanofibers with a diameter of 20 to 100 nm, and the thickness of the nylon 6 nanofiber membrane is 20 to 50 μm.

[0008] As a further improvement of the present invention, the substrate is a nonwoven fabric with a pore size range of 10 to 50 μm.

[0009] A method for preparing a nylon 6 nanofiber virus-removing filter membrane as described above, comprising the following steps:

[0010] S1. Nylon 6 nanofibers with a diameter range of 20-100 nm were crushed and placed in ethanol. The mixture was stirred at high speed for 1-10 min using a blade mixer to obtain a nylon 6 nanofiber pre-dispersion.

[0011] S2. The nylon 6 nanofiber pre-dispersion obtained in step S2 is placed in a high-pressure homogenizer for circulation dispersion to obtain a stable nylon 6 nanofiber dispersion.

[0012] S3. The nylon 6 nanofiber dispersion obtained in step S3 is wet-coated onto a nonwoven fabric substrate and naturally dried to obtain a composite fiber membrane.

[0013] S4. The composite fiber membrane obtained in step S3 is hot-pressed with a copper plate at a temperature of 80-120°C for 40-80 minutes to obtain the nylon 6 nanofiber virus-removing filter membrane.

[0014] As a further improvement of the present invention, in step S2, when the nylon 6 nanofiber pre-dispersion liquid is circulated and dispersed in the high-pressure homogenizer, the dispersion pressure is gradually increased at a rate of 30 to 100 bar / min. When the pressure rises to 800 to 1200 bar, the pressure is stopped and released after 1 to 10 minutes to complete the dispersion of the nylon 6 nanofiber dispersion liquid.

[0015] As a further improvement of the present invention, in step S1, the solid content of nylon 6 nanofibers in the nylon 6 nanofiber pre-dispersion liquid is 0.5% to 2%.

[0016] As a further improvement of the present invention, in step S1, the nylon 6 nanofibers are prepared by a multiphase melt blending phase separation method.

[0017] As a further improvement of the present invention, in step S1, the nylon 6 nanofibers are broken and have a length range of 10 to 100 μm.

[0018] As a further improvement of the present invention, in step S3, the nonwoven nonwoven fabric substrate is one of PP, PET, or PE.

[0019] The present invention also provides an application of a nylon 6 nanofiber virus-removing filter membrane, which is used in the preparation process of biological pharmaceutical products to remove small viruses during their separation and purification.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention discloses a nylon 6 nanofiber virus-removing filter membrane, comprising a substrate and a nylon 6 nanofiber membrane composited on the surface of the substrate. The average pore size of the virus-removing filter membrane is 20 nm, and the surface of the virus-removing filter membrane is charged. In the preparation process of this virus-removing filter membrane, nylon 6 nanofibers within a certain diameter range are selected and composited onto the surface of the substrate in a stable dispersed state to obtain a virus-removing filter membrane with an average pore size of 20 nm, achieving the effect of blocking small viruses while minimizing the retention of protein molecules. Furthermore, the charged surface of the filter membrane prevents proteins with the same surface charge from adhering to the fiber surface, and the good hydrophilicity of nylon 6 nanofibers reduces the non-specific adsorption of proteins by the filter membrane. This nylon 6 nanofiber virus-removing filter membrane can be applied in the field of biopharmaceutical products and is of great significance for the separation and purification of biological agents.

[0022] 2. This invention uses a large-pore nonwoven fabric as the support layer, and uniformly stacks nylon 6 nanofibers on the surface of the nonwoven fabric in a stable and dispersed manner. This not only avoids excessive adhesion between fibers, which would affect the flux of the virus-removing filter membrane, and prevents the filter membrane from retaining protein molecules, but also allows the nanofibers to be "anchored" in the large pores of the nonwoven fabric, forming a strong composite membrane. Dispersing the nylon 6 nanofibers facilitates the partial bonding of active groups on the fiber surface, allowing for smooth film formation on the nonwoven fabric surface. Furthermore, this invention uses a copper plate at a relatively low temperature during hot pressing and controls the hot pressing time. This is to improve the bonding between nylon 6 nanofibers and between the nanofibers and the nonwoven fabric, thereby improving the mechanical properties of the filter membrane. It also avoids damage to the composite membrane structure caused by hot pressing, which could lead to excessive compression between fibers and adversely affect the flux of the filter membrane. Attached Figure Description

[0023] Figure 1 The microstructure of the nylon 6 nanofiber virus-removing filter membrane prepared in Example 1 is shown at different magnifications. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0026] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0027] A nylon 6 nanofiber virus-removing filter membrane includes a substrate and a nylon 6 nanofiber membrane laminated on the surface of the substrate. The average pore size of the virus-removing filter membrane is 20 nm, and the surface of the filter membrane is charged. The microporous structure of this virus-removing filter membrane enables it to block small viruses while minimizing the retention of protein molecules. Furthermore, the charged surface of the filter membrane prevents proteins with the same surface charge from adhering to the fiber surface. The good hydrophilicity of the nylon 6 nanofibers reduces the non-specific adsorption of proteins by the filter membrane. This nylon 6 nanofiber virus-removing filter membrane can be applied in the field of biopharmaceutical products and is of great significance for the separation and purification of biological agents.

[0028] Specifically, the nylon 6 nanofiber membrane is composed of nylon 6 nanofibers with a diameter of 20–100 nm and a thickness of 20–50 μm. The substrate is a nonwoven fabric with a pore size range of 10–50 μm. This invention uses a large-pore nonwoven fabric as a support layer, uniformly stacking nylon 6 nanofibers on the surface of the nonwoven fabric in a stable, dispersed manner. This not only avoids excessive adhesion between fibers, which would affect the flux of the virus-removing filter membrane and reduce the retention rate of protein molecules, but also allows the nanofibers to be "anchored" in the large pores of the nonwoven fabric, forming a strong bond between the two to form a composite membrane. This improves the overall structural integrity of the filter membrane and extends its service life.

[0029] A method for preparing a nylon 6 nanofiber virus-removing filter membrane includes the following steps:

[0030] S1. Nylon 6 nanofibers with a diameter range of 20-100 nm are crushed and placed in ethanol, and stirred at high speed for 1-10 min using a blade mixer to obtain a nylon 6 nanofiber pre-dispersion liquid; the solid content of nylon 6 nanofibers in the nylon 6 nanofiber pre-dispersion liquid is 0.5%-2%;

[0031] S2. The nylon 6 nanofiber pre-dispersion obtained in step S2 is placed in a high-pressure homogenizer for circulation dispersion to obtain a stable nylon 6 nanofiber dispersion.

[0032] S3. The nylon 6 nanofiber dispersion obtained in step S3 is wet-coated onto a nonwoven nonwoven fabric substrate and naturally dried to obtain a composite fiber membrane.

[0033] S4. The composite fiber membrane obtained in step S3 is hot-pressed with a copper plate at a temperature of 80-120°C for 40-80 minutes to obtain a nylon 6 nanofiber virus-removing filter membrane.

[0034] This invention uses a copper plate at a lower temperature during hot pressing and controls the hot pressing time. On the one hand, this is to improve the bonding between nylon 6 nanofibers and between nanofibers and nonwoven fabric, thereby improving the mechanical properties of the filter membrane. On the other hand, it is to avoid the hot pressing damaging the structure of the composite membrane, causing excessive compression between fibers, which would adversely affect the flux of the filter membrane.

[0035] Specifically, in step S2, when the nylon 6 nanofiber pre-dispersion liquid is circulated and dispersed in a high-pressure homogenizer, the dispersion pressure is gradually increased at a rate of 30–100 bar / min. When the pressure rises to 800–1200 bar, the pressurization is stopped, and the pressure is released after 1–10 minutes, thus completing the dispersion of the nylon 6 nanofiber dispersion liquid. Nylon 2 nanofibers are dispersed at high speed using a mixer and then treated with a high-pressure homogenizer to ensure they remain in a stable dispersed state during coating. This allows for uniform deposition onto the surface of the nonwoven fabric, preparing microporous nanofibers with a uniform structure. This avoids the problem of uneven fiber membrane structure caused by uneven dispersion of nylon 6 nanofibers, which increases the protein retention rate of the filter membrane. Furthermore, the efficient dispersion of nylon 6 nanofibers facilitates the partial bonding of active groups on the fiber surface, enabling successful film formation on the nonwoven fabric surface.

[0036] In step S1, in practical applications, after the nylon 6 nanofibers are crushed and placed in ethanol, a surfactant can be added, including one of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. The amount of surfactant added is 0.1 to 2 times the mass of the nanofibers. By surface-activating the nylon 6 nanofibers, the active groups between the fibers are partially bonded, and a film is successfully formed on the surface of the nonwoven fabric.

[0037] Nylon 6 nanofibers were prepared using a multiphase melt blending phase separation method. After being broken up, the lengths of the nylon 6 nanofibers ranged from 10 to 100 μm. The nylon 6 nanofibers prepared by this method do not adhere to each other and exist as single fibers, which is beneficial to the uniformity of subsequent film formation. Furthermore, their small average diameter is conducive to forming nanoscale pore size filter membranes that can block viruses.

[0038] In some specific embodiments, in step S3, the nonwoven fabric substrate is one of PP, PET, or PE.

[0039] An application of a nylon 6 nanofiber virus-removing filter membrane is disclosed. The nylon 6 nanofiber virus-removing filter membrane is used in the preparation process of biological pharmaceutical products to remove small viruses during their separation and purification.

[0040] Example 1

[0041] This embodiment provides a method for preparing a nylon 6 nanofiber virus-removing filter membrane, including the following steps:

[0042] S1. Nylon 6 nanofibers (average diameter 30 nm) prepared by multiphase melt blending phase separation method were crushed and placed in ethanol. The average length after crushing was 30 μm. The mixture was stirred at high speed for 5 min using a blade mixer to obtain a nylon 6 nanofiber pre-dispersion. The solid content of nylon 6 nanofibers in the nylon 6 nanofiber pre-dispersion was 1.0%.

[0043] S2. Place the nylon 6 nanofiber pre-dispersion obtained in step S2 into a high-pressure homogenizer for circulation dispersion. Gradually increase the dispersion pressure at a rate of 50 bar / min. Stop pressurizing when the pressure reaches 1000 bar. Release the pressure after 5 minutes to obtain a stable nylon 6 nanofiber dispersion.

[0044] S3. The nylon 6 nanofiber dispersion obtained in step S3 is wet-coated onto a nonwoven nonwoven fabric substrate and naturally dried to obtain a composite fiber membrane.

[0045] S4. The composite fiber membrane obtained in step S3 is hot-pressed with a copper plate at a temperature of 100°C for 60 minutes to obtain a nylon 6 nanofiber virus-removing filter membrane. The average pore size of the virus-removing filter membrane is 20 nm, and the thickness of the nylon 6 nanofiber membrane is 30 μm. The surface of the virus-removing filter membrane is positively charged, which can prevent positively charged proteins from adhering to the fiber surface during application.

[0046] Please see Figure 1 The figures shown are microstructure diagrams of the nylon 6 nanofiber virus-removing filter membrane prepared in Example 1 at different magnifications. As can be seen from the figures, the nanofibers are uniformly cross-linked, forming a nanofiber membrane layer with a uniform microporous structure on the surface of the nonwoven fabric.

[0047] Comparative Example 1

[0048] Comparative Example 1 provides a method for preparing a nylon 6 nanofiber virus-removing filter membrane. The difference from Example 1 is that a nylon 6 nanofiber membrane with a thickness of 30 μm is prepared on the surface of a nonwoven fabric substrate by electrospinning to obtain a composite fiber membrane. Then, the membrane is subjected to hot pressing treatment in step S4 to obtain the nylon 6 nanofiber virus-removing filter membrane.

[0049] Comparative Example 2

[0050] Comparative Example 2 provides a method for preparing a nylon 6 nanofiber virus-removing filter membrane. The difference from Example 1 is that step S2 is not performed. The rest is roughly the same as Example 1, and will not be described again here.

[0051] Comparative Example 3

[0052] Comparative Example 3 provides a method for preparing a nylon 6 nanofiber virus-removing filter membrane. The difference from Example 1 is that step S4 is not performed. The rest is roughly the same as Example 1, and will not be described again here.

[0053] The virus-removing filter membranes prepared in Examples 1-2 and Comparative Examples 1-3 were tested for pore size statistics, mechanical properties, and virus removal performance. The results are shown in the table below.

[0054] Table 1. Performance characterization of filtration membranes in Examples 1-2 and Comparative Examples 1-3

[0055]

[0056] Table 1 shows that, as seen in Example 1, the nylon 6 nanofibers obtained by this method have good dispersion and film-forming effects, and the obtained nylon nanofibers all have high virus rejection rates and positively charged protein recovery rates. As seen in Comparative Example 1, the average pore size of the nylon 6 nanofiber membrane obtained by electrospinning is 200 nm, and the prepared filter membrane cannot meet the requirements for virus removal filtration. As seen in Comparative Example 2, without dispersion treatment by a high-pressure homogenizer, the nylon nanofibers cannot be uniformly dispersed, and the formed nanofiber membrane has a large pore size, which cannot meet the requirements for virus removal filtration. As seen in Comparative Example 3, without the hot pressing treatment in step S4, the mechanical properties of the nylon nanofiber membrane are poor, and it cannot maintain structural stability during filtration.

[0057] Example 2

[0058] This embodiment provides a method for preparing a nylon 6 nanofiber virus-removing filter membrane. The difference from Embodiment 1 is that in step S4, the hot pressing temperature is 80°C. The rest is roughly the same as in Embodiment 1, and will not be repeated here.

[0059] Example 3

[0060] This embodiment provides a method for preparing a nylon 6 nanofiber virus-removing filter membrane. The difference from Embodiment 1 is that in step S4, the hot pressing temperature is 120°C. The rest is roughly the same as in Embodiment 1 and will not be repeated here.

[0061] Comparative Example 4

[0062] Comparative Example 4 provides a method for preparing a nylon 6 nanofiber virus-removing filter membrane. The difference from Example 1 is that hot pressing is not performed in step S4. The rest is roughly the same as Example 1, and will not be described again here.

[0063] Comparative Example 5

[0064] Comparative Example 5 provides a method for preparing a nylon 6 nanofiber virus-removing filter membrane. The difference from Example 1 is that in step S4, the hot pressing temperature is 50°C. The rest is roughly the same as in Example 1 and will not be described again here.

[0065] Comparative Example 6

[0066] Comparative Example 6 provides a method for preparing a nylon 6 nanofiber virus-removing filter membrane. The difference from Example 1 is that in step S4, the hot pressing temperature is 150°C. The rest is roughly the same as in Example 1 and will not be described again here.

[0067] The virus-removing filter membranes prepared in Examples 2-3 and Comparative Examples 4-6 were tested for pore size statistics, mechanical properties, and virus removal performance. The results are shown in the table below.

[0068] Table 3. Membrane performance characterization of Examples 2-3 and Comparative Examples 4-6

[0069]

[0070] Table 3 shows that the heat treatment temperature affects the mechanical properties of nylon nanofiber membranes, thus affecting their structural stability during the filtration process. The optimal heat treatment temperature is 80–120℃. When the hot-pressing temperature is below 80℃ or there is no hot-pressing, the tensile strength of the nylon nanofiber membrane is low, and the structural stability is also poor. When the temperature exceeds 120℃, it will affect the pore size of the nylon nanofiber membrane, thus affecting its filtration effect.

[0071] In summary, this invention provides a nylon 6 nanofiber virus-removing filter membrane, its preparation method, and its application. The membrane includes a substrate and a nylon 6 nanofiber membrane composited on the substrate surface. The average pore size of the virus-removing filter membrane is 20 nm, and the membrane surface is charged. During the preparation of this virus-removing filter membrane, nylon 6 nanofibers within a specific diameter range are selected and composited onto the substrate surface in a stable dispersed state to obtain a virus-removing filter membrane with an average pore size of 20 nm. This achieves the effect of blocking small viruses while minimizing protein entrapment. Furthermore, the charged surface of the filter membrane prevents proteins with the same surface charge from adhering to the fiber surface, and the good hydrophilicity of nylon 6 nanofibers reduces the non-specific adsorption of proteins by the filter membrane. This nylon 6 nanofiber virus-removing filter membrane can be applied in the field of biopharmaceutical products and is of great significance for the separation and purification of biological agents.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A nylon 6 nanofiber virus-removing filter membrane, characterized in that, The filter includes a substrate and a nylon 6 nanofiber membrane composited on the surface of the substrate. The average pore size of the virus-removing filter membrane is 20 nm, and the surface of the virus-removing filter membrane is charged.

2. The nylon 6 nanofiber virus-removing filter membrane according to claim 1, characterized in that, The nylon 6 nanofiber membrane is composed of nylon 6 nanofibers with a diameter of 20-100 nm and a thickness of 20-50 μm.

3. The nylon 6 nanofiber virus-removing filter membrane according to claim 1, characterized in that, The substrate is a nonwoven fabric with a pore size ranging from 10 to 50 μm.

4. A method for preparing a nylon 6 nanofiber virus-removing filter membrane according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Nylon 6 nanofibers with a diameter range of 20-100 nm were crushed and placed in ethanol. The mixture was stirred at high speed for 1-10 min using a blade mixer to obtain a nylon 6 nanofiber pre-dispersion. S2. The nylon 6 nanofiber pre-dispersion obtained in step S2 is placed in a high-pressure homogenizer for circulation dispersion to obtain a stable nylon 6 nanofiber dispersion. S3. The nylon 6 nanofiber dispersion obtained in step S3 is wet-coated onto a nonwoven fabric substrate and naturally dried to obtain a composite fiber membrane. S4. The composite fiber membrane obtained in step S3 is hot-pressed with a copper plate at a temperature of 80-120°C for 40-80 minutes to obtain the nylon 6 nanofiber virus-removing filter membrane.

5. The method for preparing the nylon 6 nanofiber virus-removing filter membrane according to claim 4, characterized in that, In step S2, when the nylon 6 nanofiber pre-dispersion liquid is circulated and dispersed in the high-pressure homogenizer, the dispersion pressure is gradually increased at a rate of 30 to 100 bar / min. When the pressure rises to 800 to 1200 bar, the pressure is stopped and released after 1 to 10 minutes to complete the dispersion of the nylon 6 nanofiber dispersion liquid.

6. The method for preparing the nylon 6 nanofiber virus-removing filter membrane according to claim 4, characterized in that, In step S1, the solid content of nylon 6 nanofibers in the nylon 6 nanofiber pre-dispersion liquid is 0.5% to 2%.

7. The method for preparing the nylon 6 nanofiber virus-removing filter membrane according to claim 4, characterized in that, In step S1, the nylon 6 nanofibers are prepared by a multiphase melt blending phase separation method.

8. The method for preparing the nylon 6 nanofiber virus-removing filter membrane according to claim 4, characterized in that, In step S1, the nylon 6 nanofibers are broken down to a length range of 10–100 μm.

9. The method for preparing the nylon 6 nanofiber virus-removing filter membrane according to claim 4, characterized in that, In step S3, the nonwoven fabric substrate is one of PP, PET, or PE.

10. The application of a nylon 6 nanofiber virus-removing filter membrane prepared by any one of claims 1 to 3 or by any one of claims 4 to 9, characterized in that, The nylon 6 nanofiber virus-removing filter membrane is used in the preparation process of biological pharmaceutical products to remove tiny viruses during their separation and purification.

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