A polypeptide-separation-purification antibacterial-antifouling high-flux polyether sulfone membrane

Abstract

The present application relates to a kind of polypeptide separation and purification antibacterial anti-pollution high-flux polyether sulfone membrane, the present application is by dissolving substrate in solvent, and adding pore-forming agent and the modifier synthesized, heating stirring to form yellow transparent casting membrane liquid.Modifier is mainly prepared by synthesizing amino acid hydrochloride.D-A modifier is blended with substrate, solvent and pore-forming agent, and the effect of blending modification is achieved.The experiment uses phase inversion process to prepare a kind of polypeptide separation and purification antibacterial anti-pollution high-flux polyether sulfone membrane.The present application has the advantages that the synthesis condition of modifier is mild, and the method is simple;The addition of modifier realizes the hydrophilization modification of membrane surface, also significantly improves the antibacterial, anti-pollution performance and flux of membrane, is conducive to the long-term stable operation of membrane, and has good permeation rate to polypeptide, has very good rejection rate to macromolecular impurities, and the prepared polypeptide separation and purification antibacterial anti-pollution high-flux polyether sulfone membrane has wide application.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of polypeptide separation and purification antibacterial anti-pollution high-flux polyether sulfone membrane, belong to the technical field of separation membrane preparation, the modified membrane has high pure water flux, polypeptide transmission shows well, with good anti-fouling, antibacterial effect and other advantages, suitable for polypeptide separation and other fields. BACKGROUND

[0002] With the development of bioengineering technology, a large number of bioengineering products are constantly emerging. In recent years, based on genetic engineering technology research, a new series of polypeptide and protein substances are developed and manufactured. Polypeptide has strong activity and can be widely used in medicine, vaccine, clinical research and other medical fields. However, the separation and purification technology in the preparation process of polypeptide is one of the main reasons for its high cost. Traditional polypeptide separation technology includes salting-out method, gel filtration method, isoelectric point precipitation method, affinity chromatography and the like. These traditional methods have the disadvantages of high water consumption and high energy consumption. The application of membrane separation technology in polypeptide separation and purification can greatly reduce energy consumption and improve economic benefits.

[0003] Polyether sulfone is a thermoplastic polymer material with excellent comprehensive performance. By phase separation method, polyether sulfone can be made into a semi-permeable membrane material with porous structure. Polyether sulfone membrane shows excellent oxidation resistance, thermal stability, hydrolysis resistance and good mechanical properties. The membrane structure of polyether sulfone membrane prepared by phase separation is affected by multiple factors in the preparation process, including the concentration of polyether sulfone casting solution, the type of solvent, the type of modifier added, the operation temperature and the type of coagulation bath. Polyether sulfone membrane is used in clinical hemodialysis, plasma separation, industrial wastewater treatment, oil-water separation, ultrafiltration clarification of cane sugar, refining of edible oil and other fields. However, polyether sulfone membrane has hydrophobicity and is easy to adsorb non-polar solutes, colloidal particles and microorganisms and other impurities in water environment system for a long time, which leads to reduction of membrane flux, instability of separation performance and shortening of service life of polyether sulfone membrane.

[0004] Polyether sulfone membrane with anti-pollution and antibacterial effect and high flux can be widely used in actual production. At present, domestic and foreign researches on anti-pollution and protein retention effect of polyether sulfone membrane in separation process are carried out, but there are few researches on application of polyether sulfone membrane to polypeptide and other bio-manufactured products. Therefore, it is necessary to prepare an antibacterial anti-pollution high-flux hydrophilic modified polyether sulfone membrane with good protein retention performance, which meets the requirements of polypeptide separation and purification. SUMMARY

[0005] The purpose of the present application is to solve the problem that the membrane is easily contaminated, and to meet the requirements of membrane separation. A polypeptide separation and purification antibacterial and anti-fouling high-flux polyether sulfone membrane is prepared. The method for preparing the hydrophilic modified polyether sulfone membrane has the advantages of high flux, good anti-fouling performance, and good polypeptide permeation effect, and is suitable for membrane separation process, which can ensure excellent separation effect and long-term stable operation.

[0006] The polypeptide separation and purification antibacterial and anti-fouling high-flux polyether sulfone membrane prepared by the present application is prepared by blending modification method, and then the casting solution is prepared by phase separation method, which comprises the following steps:

[0007] Step 1): The substances involved in the synthesis step of the D-A modifier are composed of the following mass percentages: polyvinyl alcohol 0.5-2%, dimethyl sulfoxide 12.5-20%, amino acid hydrochloride 2-3%, and acetone 75-85%. Polyvinyl alcohol and dimethyl sulfoxide are mixed and dissolved under the condition of 55-65 ℃, and the pH is adjusted to 3-4 with sulfuric acid solution. The weighed amino acid hydrochloride is added to the above solution and ultrasonically dissolved for 5-10 min; with the aid of light induction technology, the solution is irradiated with a UV lamp with a wavelength of 365 nm for 15-30 min; 120-130 ℃ oil bath stirring for 16-24 h; the obtained filtrate is added with acetone solution; the filtrate is filtered again, and the residue is Soxhlet extracted. The residue is soaked in the acetone extraction solution, and siphoned at 80-84 ℃ until the acetone extraction solution is clear, to obtain the D-A modifier; vacuum drying, grinding into powder;

[0008] Step 2): The casting solution is prepared by the following components with mass percentage: polyether sulfone 15-20%, pore former 40-60%, D-A modified material 0.25-1%, and the remaining amount is solvent. The base material is a hydrophobic polymer, which is dissolved in a solvent and then the pore former is added and stirred under heating. After dissolution, the D-A modified material prepared in step (1) is dissolved in the solvent and added, and the stirring is continued until a transparent casting solution is formed. After standing and degassing, it is ready for use;

[0009] Step 3) Preparation of modified membrane: the casting solution in step (2) is spread into a thin layer by using a doctor blade, and then immersed in a phase inversion liquid for phase inversion. The thickness of the thin layer formed by spreading the casting solution is 150-250 µm. The solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid, to obtain an antibacterial and anti-fouling high-flux hydrophilic modified polyether sulfone membrane, which is immersed in a phase inversion liquid for storage.

[0010] Preferably, the stirring time of the D-arginine hydrochloride in step 1) is 16-24 h.

[0011] Preferably, the amino acid hydrochloride material in step 1) is one or more of D-arginine hydrochloride, L-arginine hydrochloride, and lysine hydrochloride.

[0012] Preferably, the solvent in step 2) can be one of N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, N-methyl pyrrolidone.

[0013] Preferably, the pore-making agent in step 2) can be one of polyethylene glycol (MW=400-8000), hydroxypropyl cellulose, polyvinylpyrrolidone.

[0014] Preferably, the mass percentage of the D-A modifier in step 2) is 0.25-1%.

[0015] Preferably, the phase inversion liquid in step 3) is one of ethanol aqueous solution with an ethanol volume fraction of 0%, 20%, 40%, 60%, 80%, and 100%.

[0016] The polypeptide separation and purification antibacterial and anti-pollution high-flux polyether sulfone membrane prepared by the method has the characteristics that the pure water flux of the composite membrane is 600-800 L·m -2 ·h -1 , the bovine serum albumin retention rate is greater than or equal to 99%, the polypeptide permeation rate is greater than or equal to 99%, and the antibacterial effect is obvious. Advantages

[0017] Compared with the prior art, the film is modified by the blending method, the modified monomer is dissolved in the casting solution, the stability is greatly improved, and then the modified polyether sulfone membrane with high flux, good anti-pollution and antibacterial performance, good polypeptide permeation performance, and long-term stability is prepared by the non-solvent induced phase inversion method. The introduction of ammonium ions in the base material enhances the hydrophilicity and improves the antifouling performance, thereby ensuring the long-term stability of the membrane. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The dense surface scanning electron microscope graph of the polyether sulfone modified membrane of the embodiment one of the application

[0019] Figure 2 The dense surface scanning electron microscope graph of the polyether sulfone modified membrane of the embodiment three of the application

[0020] Figure 3 The cross-section scanning electron microscope graph of the polyether sulfone modified membrane of the embodiment five of the application

[0021] Figure 4 The casting solution graph of the polyether sulfone modified membrane of the embodiment eight of the application IMPLEMENTATION

[0022] The application will be further described below in combination with specific embodiments. EMBODIMENT

[0023] Step 1): Preparation of D-A modifier: The substances involved in the synthesis of the D-A modifier in the step are composed of polyvinyl alcohol 2.2 g, dimethyl sulfoxide 50 ml, D-arginine hydrochloride 9.1 g, acetone 300 ml. The polyvinyl alcohol is mixed and dissolved with dimethyl sulfoxide at 65 ℃, and the pH is adjusted to 3.5 with an aqueous solution of sulfuric acid. The weighed amino acid hydrochloride is added to the above solution and ultrasonicated for 10 min until completely dissolved; by means of light induction technology, a UV lamp with a wavelength of 365 nm is used for irradiation for 20 min; 120 ℃ oil bath stirring for 24 h; the filtrate obtained by reduced pressure filtration is added with acetone solution; again filtration, Soxhlet extraction is carried out on the filter residue. The filter residue is soaked in the acetone extraction liquid, and siphoned at 80 ℃ until the acetone extraction liquid is clear, i.e. the D-A modifier is obtained; vacuum drying, grinding into powder;

[0024] Step 2): The casting solution is prepared by the following components, the substrate is polyether sulfone 17 g, the pore former is polyethylene glycol (MW=400) 43 g, the D-A modified material is 0.25 g, and the remaining amount is the solvent N,N-dimethylacetamide. Dissolve in solvent, then add pore former and stir under heating, after dissolution, add the D-A modified material prepared in (1) to the solvent, continue to stir until a transparent casting solution is formed, and stand for degassing, ready for use;

[0025] Step 3) Preparation of modified membrane: using a doctor blade, set the speed to 30 mm / s, spread the casting solution in step (2) into a thin layer, then immerse it in the phase inversion liquid for phase inversion, the phase inversion liquid is pure water. The thickness of the thin layer formed by the casting solution is 250 µm. The solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid to obtain an antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane, which is immersed in the phase inversion liquid for storage.

[0026] The pure water flux of the composite membrane is 600 L·m -2 ·h -1 , the BSA rejection rate is ≥99.1%, the polypeptide permeation rate is ≥99.3%, and when the membrane piece is placed on the surface of the culture medium containing gram-negative escherichia coli and staphylococcus aureus and cultured, the colony counts of escherichia coli and staphylococcus aureus are successively reduced, and a bacterial inhibition zone is formed near the membrane, indicating that the membrane has good antibacterial effect. The SEM image of the dense surface of the membrane is shown in Figure 1 . Example

[0027] Step 1): Preparation of D-A modifier: The substances involved in the synthesis of the D-A modifier in the step are composed of polyvinyl alcohol 2.2 g, dimethyl sulfoxide 50 ml, D-arginine hydrochloride 9.0 g, and acetone 300 ml. The polyvinyl alcohol is mixed and dissolved with dimethyl sulfoxide at 55 ℃, and the pH is adjusted to 3 with an aqueous solution of sulfuric acid. The weighed amino acid hydrochloride is added to the above solution and ultrasonically dissolved for 5 min; by means of light induction technology, a UV lamp with a wavelength of 365 nm is used for irradiation for 30 min; 120 ℃ oil bath stirring for 20 h; the filtrate obtained by reduced pressure filtration is added with acetone solution; again filtration, Soxhlet extraction is carried out on the filter residue. The filter residue is soaked in the acetone extraction liquid, and siphoned at 81 ℃ until the acetone extraction liquid is clear, to obtain the D-A modifier; vacuum drying, grinding into powder;

[0028] Step 2): The casting solution is prepared by the following components: the base material is polyether sulfone 15 g, the pore former is polyethylene glycol (MW=6000) 45 g, the D-A modified material is 0.5 g, and the remaining amount is the solvent N,N-dimethylformamide. Dissolve it in the solvent, add the pore former and stir under heating, after dissolution, add the D-A modified material prepared in (1) to the solvent, continue to stir until a transparent casting solution is formed, and stand for degassing, ready for use;

[0029] Step 3) Preparation of modified membrane: using a doctor blade, set the speed to 10 mm / s, spread the casting solution in step (2) into a thin layer, then immerse it in the phase inversion liquid for phase inversion. The phase inversion liquid is an ethanol aqueous solution with an ethanol volume fraction of 40%. The thin layer formed by spreading the casting solution has a thickness of 250 µm. The solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid to obtain an antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane, which is immersed in the phase inversion liquid for storage.

[0030] The pure water flux of the composite membrane is 630 L·m -2 ·h -1 , the BSA rejection rate is ≥99.2%, the polypeptide permeation rate is ≥99.3%, and the membrane piece is placed on the surface of the culture medium containing gram-negative escherichia coli and staphylococcus aureus for culture. It can be observed that the colony counts of escherichia coli and staphylococcus aureus decrease successively, and a bacterial inhibition zone is formed near the membrane, indicating that the membrane has good antibacterial effect. Example

[0031] Step 1): Preparation of D-A modifier: The substances involved in the synthesis of D-A modifier in the step are composed of polyvinyl alcohol 2.2 g, dimethyl sulfoxide 50 ml, L-arginine hydrochloride 9.2 g, acetone 300 ml. The polyvinyl alcohol is mixed and dissolved with dimethyl sulfoxide at 60 ℃, and the pH is adjusted to 4 with aqueous sulfuric acid solution. The weighed amino acid hydrochloride is added to the above solution and ultrasonically dissolved for 6 min; by means of light induction technology, the ultraviolet lamp with wavelength of 365 nm is irradiated for 15 min; 130 ℃ oil bath stirring for 16 h; the filtrate obtained by reduced pressure filtration is added with acetone solution; again filtration, Soxhlet extraction is carried out on the filter residue. The filter residue is soaked in acetone extraction liquid, and siphoned at 82 ℃ until the acetone extraction liquid is clear, to obtain the D-A modifier; vacuum drying, grinding into powder;

[0032] Step 2): The casting solution is prepared by the following components, the substrate is polyether sulfone 17 g, the pore former is polyethylene glycol (MW=8000) 43 g, the D-A modified material is 0.75 g, and the remaining amount is the solvent dimethyl sulfoxide. Dissolve in solvent, add pore former and stir under heating, after dissolution, add the D-A modified material prepared in (1) to the solvent, continue to stir until a transparent casting solution is formed, and stand for degassing, ready for use;

[0033] Step 3) Preparation of modified membrane: using a doctor blade, set the speed to 20 mm / s, spread the casting solution in step (2) into a thin layer, then immerse it in the phase inversion liquid for phase inversion. The phase inversion liquid is an ethanol aqueous solution with a volume fraction of 60% ethanol. The thickness of the thin layer formed by the casting solution is 175 µm. The solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid to obtain an antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane, which is immersed in the phase inversion liquid for storage.

[0034] The pure water flux of the composite membrane is 612 L·m -2 ·h -1 , the BSA rejection rate is ≥99.4%, the polypeptide permeation rate is ≥99.2%, and the membrane piece is placed on the surface of the culture medium containing gram-negative escherichia coli and staphylococcus aureus for culture. It can be observed that the colony numbers of escherichia coli and staphylococcus aureus decrease successively, and a bacterial inhibition zone is formed near the membrane, indicating that the membrane has good antibacterial effect. The SEM image of the dense surface of the membrane is shown in Figure 2 . Example

[0035] Step 1): Preparation of D-A modifier: The substances involved in the synthesis of the D-A modifier in the step are composed of polyvinyl alcohol 2.2 g, dimethyl sulfoxide 50 ml, lysine hydrochloride 9.1 g, and acetone 300 ml. The polyvinyl alcohol is mixed and dissolved with dimethyl sulfoxide at 63 ℃, and the pH is adjusted to 3.5 with an aqueous solution of sulfuric acid. The weighed amino acid hydrochloride is added to the above solution and ultrasonically dissolved for 7 min; with the aid of light induction technology, a UV lamp with a wavelength of 365 nm is used for irradiation for 20 min; 125 ℃ oil bath stirring for 24 h; the filtrate obtained by reduced pressure filtration is added with acetone solution; again, filtration is carried out, and the filtrate is subjected to Soxhlet extraction. The filtrate is soaked in the acetone extraction liquid, and siphoned at 83 ℃ until the acetone extraction liquid is clear, to obtain the D-A modifier; vacuum drying, grinding into powder;

[0036] Step 2): The casting solution is prepared by the following components: the base material is polyether sulfone 17 g, the pore former is polyvinylpyrrolidone 43 g, the D-A modified material is 0.875 g, and the remaining amount is the solvent N,N-dimethylacetamide. It is dissolved in the solvent and then the pore former is added and stirred with heating. After dissolution, the D-A modified material prepared in (1) is dissolved in the solvent and added, and continues to be stirred until a transparent casting solution is formed. After standing and degassing, it is ready for use;

[0037] Step 3) Preparation of modified membrane: using a doctor blade, set the speed to 15 mm / s, spread the casting solution in step (2) into a thin layer, then immerse it in the phase inversion liquid for phase inversion. The phase inversion liquid is an ethanol aqueous solution with an ethanol volume fraction of 80%. The thin layer formed by the casting solution has a thickness of 225 µm. The solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid to obtain an antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane. The membrane is immersed in the phase inversion liquid for storage.

[0038] The pure water flux of the composite membrane is 716 L·m -2 ·h -1 , the BSA rejection rate is ≥99.6%, the polypeptide permeation rate is ≥99.3%, and the membrane piece is placed on the surface of the culture medium containing gram-negative escherichia coli and staphylococcus aureus for culture. It can be observed that the colony counts of escherichia coli and staphylococcus aureus decrease successively, and a bacterial inhibition zone is formed near the membrane, indicating that the membrane has good antibacterial effect. Example

[0039] Step 1): Preparation of D-A modifier: The substances involved in the synthesis of D-A modifier in the step are composed of polyvinyl alcohol 2.2 g, dimethyl sulfoxide 50 ml, D-arginine hydrochloride 9.1 g, acetone 300 ml. The polyvinyl alcohol is mixed and dissolved with dimethyl sulfoxide at 64 ℃, and the pH is adjusted to 3.3 with aqueous sulfuric acid solution. The weighed amino acid hydrochloride is added to the above solution and ultrasonically dissolved for 10 min; by means of light induction technology, a UV lamp with a wavelength of 365 nm is used for irradiation for 20 min; 120-130 ℃ oil bath stirring for 24 h; the filtrate obtained by reduced pressure filtration is added with acetone solution; again filtration, Soxhlet extraction is carried out on the filter residue. The filter residue is soaked in the acetone extraction liquid, and siphoned at 83 ℃ until the acetone extraction liquid is clear, to obtain the D-A modifier; vacuum drying, grinding into powder;

[0040] Step 2): The casting solution is prepared by the following components, the substrate is polyether sulfone 20 g, the pore former is polyethylene glycol (MW=400) 40 g, the D-A modified material is 1 g, and the remaining amount is the solvent N-methyl pyrrolidone. Dissolve in solvent, then add pore former and stir under heating, after dissolution, add the D-A modified material prepared in (1) to the solvent, continue to stir until a transparent casting solution is formed, and stand for degassing, ready for use;

[0041] Step 3) Preparation of modified membrane: using a doctor blade, set the speed to 25 mm / s, spread the casting solution in step (2) into a thin layer, then immerse it in the phase inversion liquid for phase inversion, the phase inversion liquid is ethanol. The thickness of the thin layer formed by the casting solution is 250 µm. The solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid to obtain an antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane, which is immersed in the phase inversion liquid for storage.

[0042] The pure water flux of the composite membrane is 646 L·m -2 ·h -1 , the BSA rejection rate is ≥99.5%, the polypeptide permeation rate is ≥99.3%, and when the membrane piece is placed on the surface of the culture medium containing gram-negative escherichia coli and staphylococcus aureus, the colony numbers of escherichia coli and staphylococcus aureus are observed to decrease successively, and a bacterial inhibition zone is formed near the membrane, indicating that the membrane has good antibacterial effect. The SEM image of the dense surface of the membrane is shown in Figure 3 . Example

[0043] Step 1): Preparation of D-A modifier: The substances involved in the synthesis of the D-A modifier in the step are composed of polyvinyl alcohol 2.2 g, dimethyl sulfoxide 50 ml, D-arginine hydrochloride 9.1 g, and acetone 300 ml. The polyvinyl alcohol is mixed and dissolved with dimethyl sulfoxide at 60 °C, and the pH is adjusted to 3.5 with an aqueous solution of sulfuric acid. The weighed amino acid hydrochloride is added to the above solution and ultrasonicated for 10 min until completely dissolved; with the aid of light induction technology, a UV lamp with a wavelength of 365 nm is used for irradiation for 20 min; 123 °C oil bath stirring for 24 h; the filtrate obtained by reduced pressure filtration is added with acetone solution; again, filtration is performed, and the filtrate is subjected to Soxhlet extraction. The filtrate is soaked in the acetone extraction liquid, and siphoned at 83 °C until the acetone extraction liquid is clear, to obtain the D-A modifier; vacuum drying, grinding into powder;

[0044] Step 2): The casting solution is prepared by the following components: the base material is polyether sulfone 17 g, the pore former is polyethylene glycol (MW=400) 43 g, the D-A modified material is 0.75 g, and the remaining amount is the solvent N,N-dimethylacetamide. It is dissolved in the solvent and then the pore former is added and stirred with heating. After dissolution, the D-A modified material prepared in (1) is dissolved in the solvent and added, and continues to be stirred until a transparent casting solution is formed. After standing and degassing, it is ready for use;

[0045] Step 3) Preparation of modified membrane: using a doctor blade, set the speed to 18 mm / s, spread the casting solution in step (2) into a thin layer, and then immerse it in the phase inversion liquid for phase inversion. The phase inversion liquid is an ethanol aqueous solution with an ethanol volume fraction of 20%. The thin layer formed by the casting solution has a thickness of 200 µm. The solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid to obtain an antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane. The membrane is immersed in the phase inversion liquid for storage.

[0046] The pure water flux of the composite membrane is 612 L·m -2 ·h -1 , the BSA rejection rate is ≥99.6%, the polypeptide permeation rate is ≥99.8%, and the membrane piece is placed on the surface of the culture medium containing gram-negative Escherichia coli and Staphylococcus aureus for culture. It can be observed that the colony counts of Escherichia coli and Staphylococcus aureus decrease successively, and a bacterial inhibition zone is formed near the membrane, indicating that the membrane has good antibacterial effect. Example

[0047] Step 1): Preparation of D-A modifier: The substances involved in the synthesis of the D-A modifier in the step are composed of polyvinyl alcohol 2.2 g, dimethyl sulfoxide 50 ml, D-arginine hydrochloride 9.1 g, and acetone 300 ml. The polyvinyl alcohol is mixed and dissolved with dimethyl sulfoxide at 65 ℃, and the pH is adjusted to 3.5 with an aqueous solution of sulfuric acid. The weighed amino acid hydrochloride is added to the above solution and ultrasonicated for 10 min until completely dissolved; with the aid of light induction technology, a UV lamp with a wavelength of 365 nm is used for irradiation for 20 min; 128 ℃ oil bath stirring for 24 h; the filtrate obtained by reduced pressure filtration is added with acetone solution; again, filtration is performed, and the filtrate is subjected to Soxhlet extraction. The filtrate is soaked in the acetone extraction liquid, and siphoned at 83 ℃ until the acetone extraction liquid is clear, to obtain the D-A modifier; vacuum drying, grinding into powder;

[0048] Step 2): The casting solution is prepared by the following components: the base material is polyether sulfone 17 g, the pore former is polyethylene glycol (MW=400) 43 g, the D-A modified material is 0.5 g, and the remaining amount is the solvent N,N-dimethylacetamide. It is dissolved in the solvent and then the pore former is added and stirred with heating. After dissolution, the D-A modified material prepared in (1) is dissolved in the solvent and added, and continues to be stirred until a transparent casting solution is formed. After standing and degassing, it is ready for use;

[0049] Step 3) Preparation of modified membrane: using a doctor blade, set the speed to 30 mm / s, spread the casting solution in step (2) into a thin layer, then immerse it in the phase inversion liquid for phase inversion. The phase inversion liquid is an ethanol aqueous solution with an ethanol volume fraction of 20%. The thin layer formed by the casting solution has a thickness of 200 µm. The solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid to obtain an antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane. The membrane is immersed in the phase inversion liquid for storage.

[0050] The pure water flux of the composite membrane is 675 L·m -2 ·h -1 , the BSA rejection rate is ≥99.6%, the polypeptide permeation rate is ≥99.3%, and when the membrane is placed on the surface of a culture medium containing gram-negative Escherichia coli and Staphylococcus aureus and cultured, the colony counts of Escherichia coli and Staphylococcus aureus are successively reduced, and a bacteriostatic ring is formed near the membrane, indicating that the membrane has good bacteriostatic effect. Example

[0051] Step 1): Preparation of D-A modifier: The substances involved in the synthesis of the D-A modifier in the step are composed of polyvinyl alcohol 2.2 g, dimethyl sulfoxide 50 ml, D-arginine hydrochloride 9.1 g, and acetone 300 ml. The polyvinyl alcohol is mixed and dissolved with dimethyl sulfoxide at 58 ℃, and the pH is adjusted to 3.5 with an aqueous solution of sulfuric acid. The weighed amino acid hydrochloride is added to the above solution and ultrasonically dissolved for 10 min; by means of light induction technology, a UV lamp with a wavelength of 365 nm is used for irradiation for 20 min; 122 ℃ oil bath stirring for 24 h; the obtained filtrate is filtered under reduced pressure, and acetone solution is added; the filtrate is filtered again, and the filtrate is extracted by Soxhlet extraction. The filtrate is soaked in the acetone extraction liquid, and the acetone extraction liquid is siphoned at 83 ℃ until it is clear, to obtain the D-A modifier; vacuum drying, grinding into powder;

[0052] Step 2): The casting solution is prepared by the following components: the base material is polyether sulfone 17 g, the pore former is polyethylene glycol (MW=6000) 43 g, the D-A modified material is 1 g, and the remaining amount is the solvent N,N-dimethylacetamide. The above-mentioned components are dissolved in the solvent, and the pore former is added and stirred under heating. After dissolution, the D-A modified material prepared in step (1) is dissolved in the solvent and added, and the stirring is continued until a transparent casting solution is formed. After standing and degassing, it is ready for use;

[0053] Step 3) Preparation of modified membrane: The casting solution in step (2) is spread into a thin layer by using a doctor blade with a speed of 30 mm / s, and then immersed in a phase inversion liquid for phase inversion. The phase inversion liquid is an ethanol aqueous solution with an ethanol volume fraction of 20%. The thickness of the thin layer formed by spreading the casting solution is 150 µm. The solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid, to obtain an antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane. The membrane is immersed in the phase inversion liquid for storage.

[0054] The pure water flux of the composite membrane is about 800 L·m -2 ·h -1 The BSA rejection rate is ≥99.8%, the polypeptide permeation rate is ≥99.5%, and the membrane piece is placed on the surface of the culture medium containing gram-negative escherichia coli and staphylococcus aureus for culture. It can be observed that the colony numbers of escherichia coli and staphylococcus aureus are successively reduced, and a bacterial inhibition zone is formed near the membrane, indicating that the membrane has good antibacterial effect.

[0055] Table 1 Comparison of flux, macromolecular impurity rejection rate and polypeptide permeation rate of the membrane according to the present application and currently marketed ultrafiltration membranes

[0056] Ultrafiltration membrane product name Pure water permeation flux L-m -2 ·h -1 ]]> Macromolecular impurity rejection rate (take bovine serum albumin as an example) Polypeptide permeability L / s 200-280 ≥90.0% ≥97.0% Dupont 260-300 ≥95.0% ≥95.0% Coflex 240-310 ≥92.0% ≥96.0% Hydron 235-310 ≥95.0% ≥98.0% The present invention 600-800 ≥99.0% ≥99.0%

Claims

1. A method for preparing a polypeptide isolated and purified antibacterial and antifouling high flux polyethersulfone membrane, characterized in that, Comprise the following steps: (1) Synthesis of D-A modifier: the substances involved in the synthesis step of D-A modifier are composed of the following mass percentages: polyvinyl alcohol 0.5-2%, dimethyl sulfoxide 12.5-20%, amino acid hydrochloride 2-3%, and acetone 75-85%; polyvinyl alcohol and dimethyl sulfoxide are mixed and dissolved at 55-65°C, and the pH is adjusted to 3-4 with an aqueous sulfuric acid solution; the weighed amino acid hydrochloride is added to the above solution and ultrasonically dissolved for 5-10 min; with the aid of light induction technology, the solution is irradiated with a 365 nm ultraviolet lamp for 15-30 min; the solution is stirred in an oil bath at 120-130°C for 16-24 h; acetone solution is added to the obtained filtrate under reduced pressure; the filtrate is filtered again, and the residue is Soxhlet extracted; the residue is soaked in the acetone extract, and siphoned at 80-84°C until the acetone extract is clear, to obtain the D-A modifier; vacuum drying and grinding into powder; (2) Preparation of casting solution: the casting solution is prepared by the following components in mass percentage: base material 15-20%, pore former 40-60%, D-A modified material 0.25-1%, and the remaining amount is solvent; the base material is polyether sulfone, which is dissolved in the solvent and then the pore former is added and stirred under heating; after dissolution, the D-A modified material prepared in (1) is dissolved in the solvent and added, and continues to be stirred until a transparent casting solution is formed, and then is left to stand and degas, ready for use; (3) Preparation of antibacterial and anti-pollution high-flux polyether sulfone membrane for polypeptide separation and purification: the casting solution in step (2) is spread into a thin layer by a doctor blade and then immersed in a phase inversion liquid for phase inversion; the thickness of the thin layer formed by spreading the casting solution is 150-250 µm; the solidified and shaped membrane is washed with pure water until there is no obvious foam in the washing liquid, to obtain an antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane, which is stored in the phase inversion liquid.

2. A method for preparing a polypeptide separated and purified antibacterial and antifouling high flux polyethersulfone membrane according to claim 1, characterized in that: The main reactant for synthesizing the modifier is one of D-arginine hydrochloride, L-arginine hydrochloride, and lysine hydrochloride.

3. A method for preparing a polypeptide separated and purified antibacterial and antifouling high-flux polyethersulfone membrane according to claim 1, characterized in that: The pore former for preparing the casting solution is one of polyethylene glycol with a molecular weight MW=400-8000, hydroxypropyl cellulose, and polyvinylpyrrolidone.

4. A method for preparing a polypeptide separated and purified antibacterial and antifouling high-flux polyethersulfone membrane according to claim 1, characterized in that: The solvent for preparing the casting solution is one of N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone.

5. A method for preparing a polypeptide separated and purified antibacterial and antifouling high-flux polyethersulfone membrane according to claim 1, characterized in that: The speed of the doctor blade for preparing the antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane is set to 10-30 mm / s.

6. A method of preparing a polypeptide isolated and purified antibacterial and antifouling high flux polyethersulfone membrane according to claim 1, characterized by: The phase inversion liquid for preparing the antibacterial and anti-pollution high-flux hydrophilic modified polyether sulfone membrane is one of ethanol aqueous solution with an ethanol volume fraction of 0%, 20%, 40%, 60%, 80%, and 100%.

7. The polypeptide separation and purification antibacterial and antifouling high-flux polyethersulfone membrane prepared by the method according to any one of claims 1-5, characterized in that, The pure water flux of the membrane is 600-800 L·m -2 ·h -1 , the bovine serum protein rejection rate is ≥99%, the polypeptide permeation rate is ≥95%, and the membrane has obvious antibacterial effect.

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