Bionic functional membrane continuous separation and purification system for liraglutide

Abstract

The invention provides a liraglutide bionic functional membrane continuous separation and purification system, the system is used for continuously operating liraglutide separation and purification at 2-8 DEG C, multiple layers of bionic functional membranes are integrated into a micro-channel to form a micro-fluidic chip, an on-line monitoring system is integrated, the separation effect is monitored in real time, and through an intelligent control system, the liraglutide can be continuously separated and purified. Optimizing a separation strategy; each layer of membrane has a specific pore diameter and surface chemical properties, selective separation is carried out aiming at substances with different molecular weights, polarities and biological characteristics, and the multilayer bionic functional membrane is formed by connecting 3-5 layers of multifunctional membranes in series; the technical problems that in an existing liraglutide purification and separation technology, efficiency is low, purity is not high, environmental pollution is serious, rapid high-purity extraction is difficult to achieve, and continuous production is difficult to achieve are solved.

Description

Technical Field

[0001] The present invention provides a liraglutide separation and purification system, and in particular relates to a liraglutide continuous separation and purification system using a biomimetic functional membrane. Background Art

[0002] Liraglutide is produced by replacing lysine 34 of endogenous GLP-1 with arginine and attaching a 16-carbon palmitoyl side chain to lysine 26. This structural alteration is intended to prolong the drug's duration of action in the body. Therefore, during production, special care must be taken to maintain the integrity of this structure and prevent unwanted chemical changes during separation and purification. This structural feature significantly increases the molecule's hydrophobicity, requiring a high proportion of organic solvents (such as acetonitrile) for dissolution during reversed-phase chromatography purification (e.g., C18 packing). However, high organic concentrations can cause peptide chain aggregation or precipitation. Furthermore, traditional purification relies on highly polar solvents (such as hexafluoroisopropanol (HFIP)) to aid dissolution, increasing cost and operational complexity.

[0003] Liraglutide has unique pharmacokinetic properties, with a prolonged time to peak plasma concentration (10 hours), a half-life of 13 hours, and 24-hour glycemic control with a single daily injection. These properties require ensuring drug stability during the production process to ensure its long-term efficacy in the body. Furthermore, as a peptide drug, liraglutide may induce an immune response. While no reports have shown a significant impact on drug efficacy and safety, care must be taken during production to avoid the introduction of impurities or allosteric variants to avoid increasing the risk of immunogenicity.

[0004] With the growing demand for efficient, environmentally friendly separation technologies in modern industry and medicine, supercritical CO2 extraction and ionic liquid separation technologies are attracting widespread attention due to their unique advantages. Supercritical CO2, as a green solvent, is non-toxic, residue-free, and highly selective. Ionic liquids, on the other hand, exhibit significant potential in separation applications due to their designability, thermal stability, and low vapor pressure.

[0005] Currently, supercritical CO2 extraction technology has been applied in various fields. For example, CN108299298B discloses a method for the efficient extraction of norisoboldine, which combines supercritical CO2 degreasing with ionic liquid aqueous solution extraction to achieve high extraction yield and purity. However, this technology still needs to improve its extraction selectivity and efficiency when dealing with complex components.

[0006] Ionic liquids, a new class of green solvents, are increasingly being used in separation technologies. CN116478042B discloses a method for recovering ethyl acetate from wastewater. Using a composite solvent of 1-allyl-3-methylimidazolium sodium chloride and ethylene glycol as an ionic liquid extractant improves separation efficiency. However, this technology still has limitations in the selectivity and stability of ionic liquids when processing high-concentration mixtures.

[0007] In practical applications, ionic liquid membrane separation technology faces problems with the plasticity and swelling of membrane materials. These problems will affect the stability and separation performance of the membrane, resulting in increased difficulty in control during the separation process. At the same time, membrane fouling is a long-standing problem in membrane separation technology. During operation, ionic liquid membranes are easily affected by physical and chemical factors, which can cause the membrane pore size to become smaller or clogged, thereby affecting the membrane's permeability and separation characteristics. Membrane flux attenuation is an important factor restricting the application of membrane separation technology. During the operation of ionic liquid membranes, a decrease in flux may lead to a significant decrease in separation efficiency. Furthermore, the preparation process of ionic liquid membranes is usually more complicated and requires highly precise control conditions, which increases the difficulty and cost of implementing the technology. In order to further improve its application effect, it is necessary to strengthen the research and development of membrane materials, optimize the preparation process to reduce production costs, and promote the maturity and popularization of the technology through exploration of practical applications.

[0008] Therefore, although the above technologies have made certain progress in the field of separation, the existing technologies still have shortcomings: First, traditional liraglutide separation methods usually require the use of large amounts of organic solvents, which not only causes environmental pollution but also increases production costs; second, it is still difficult to achieve rapid and high-purity extraction in complex components, especially for impurities with similar structures; third, the existing technologies are difficult to achieve continuous production, the batch process production cycle is long, and production capacity is limited; fourth, the synergistic mechanism of ionic liquids and supercritical CO2 has not been fully utilized, resulting in less than ideal separation efficiency and selectivity; finally, the existing membrane separation system is prone to problems such as membrane fouling and performance degradation during long-term use, affecting the stability of the separation effect.

[0009] Therefore, there is an urgent need to develop an integrated separation technology solution that is efficient, environmentally friendly, and continuous to solve the above problems. Summary of the Invention

[0010] To address the technical problems of existing liraglutide purification and separation technologies, such as low efficiency, low purity, severe environmental pollution, difficulty in achieving rapid and high-purity extraction, and difficulty in achieving continuous production, a solution for integrating a biomimetic functional membrane technology for efficient and continuous separation of liraglutide is provided. This solution can significantly improve the extraction rate and purity of liraglutide, reduce the use of organic solvents, improve production efficiency, shorten the production cycle, and achieve continuous production. At the same time, it improves the plasticity and swelling properties of the membrane material, overcomes the problem of rapid membrane flux attenuation caused by membrane fouling, simplifies the preparation process, and reduces production costs.

[0011] The present invention provides a biomimetic functional membrane continuous separation and purification system for liraglutide, wherein the system is used for continuous separation and purification of liraglutide at 2-8°C. The system is composed of multiple layers of biomimetic functional membranes integrated into microchannels to form a microfluidic chip, and an integrated online monitoring system to monitor the separation effect in real time. The separation strategy is optimized through an intelligent control system. The multilayer biomimetic functional membrane, each layer of which has a specific pore size and surface chemical properties, selectively separates substances with different molecular weights, polarities, and biological characteristics. The preparation method thereof comprises: 1) Selecting one or more of polyethersulfone (PES), polyvinylidene fluoride (PVDF) or polysulfone (PSf) as the membrane matrix material and preparing the base membrane by phase inversion method; 2) Using plasma treatment or chemical grafting technology to modify the surface of the base membrane to form a multifunctional membrane and improve the selectivity and anti-fouling ability of the membrane; The multilayer biomimetic functional membrane is formed by 3 to 5 layers of multifunctional membranes connected in series. The multifunctional membrane includes modifying hydrophobic groups on the surface of the base membrane for adsorbing non-polar substances; and / or modifying cation exchange groups on the surface of the base membrane for adsorbing cations; and / or modifying anion exchange groups on the surface of the base membrane for adsorbing anions; and / or modifying affinity ligands on the surface of the base membrane for specifically adsorbing target molecules.

[0012] Liraglutide is a GLP-1 analogue consisting of 31 amino acids with a molecular weight of approximately 3.75 kDa. It relies on fatty acid chains for its long-lasting efficacy. The high hydrophobicity of fatty acid chains makes it difficult to dissolve and aggregate, precipitating; its multiple chiral centers make it difficult to separate isomeric impurities. Fatty acid side chains are easily detached at temperatures above 40°C, shortening its half-life. Liraglutide's amide bonds are susceptible to hydrolysis, and methionine and tryptophan are susceptible to oxidation, requiring low-temperature protection. The present invention utilizes a biomimetic membrane continuous separation and purification system composed of multiple layers of functionalized nanofiber membranes, which can operate continuously at 2–8°C, replacing traditional thermal concentration processes. Each membrane layer is modified with different selective groups, such as affinity ligands and ion exchange groups. The raw material solution is continuously passed through the membrane system under pressure, achieving the simultaneous separation of multiple components.

[0013] The chemical synthesis of liraglutide is prone to producing a variety of impurities with highly similar structures to liraglutide, such as chiral amino acid mismatch products. Due to their highly similar physicochemical properties to the target peptide, and when the palmitic acid side chain coupling efficiency is less than 100%, residual unmodified or partially modified peptide remains, making separation difficult using conventional chromatography. This invention combines microfluidic chip technology with biomimetic membranes integrated into microchannels to achieve continuous flow separation. This method utilizes an optimized tandem assembly of multifunctional membranes, typically with 3-5 membrane layers, to achieve optimal separation. This method achieves precise separation of liraglutide (3.75 kDa) from small molecule impurities (such as salts and pigments). This method combines surface ion modification with electrostatic repulsion to remove host proteins. Nanofiltration charge screening and biomimetic pore size are used to effectively control over 20 impurities (such as deamidation products and oxidized aggregates), meeting drug approval standards.

[0014] Traditional HPLC purification of liraglutide consumes approximately 5,000 liters of solvent (primarily acetonitrile) per kilogram. While polystyrene divinylbenzene packing is acid and alkali resistant, its dynamic binding capacity for hydrophobic peptides is low, necessitating frequent regeneration. This invention effectively addresses the three major pain points of liraglutide: thermal inactivation, residual impurities, and production interruptions. It meets the needs of large-scale production and can effectively promote the industrialization of GLP-1 drugs.

[0015] Preferably, the bionic functional membrane continuous separation and purification system provided by the present invention, wherein the microfluidic chip adopts a sandwich structure design, consisting of three layers of polydimethylsiloxane (PDMS) and two layers of glass, with multiple layers of bionic functional membranes sandwiched in the middle; the chip consists of an injection area, a membrane integration area, a separation area, a collection area, and a detection area; the injection area includes a micro-injection pump and a sample storage pool; the membrane integration area accommodates 3 or more layers of different multifunctional membranes; the separation area is designed as a serpentine channel to increase separation efficiency; the detection area contains a variety of sensors and detectors; the microfluidic chip connects each functional area through microvalves and microchannels to achieve automatic processing of samples and continuous flow separation.

[0016] Preferably, in the biomimetic functional membrane continuous separation and purification system provided by the present invention, the flow rate of the microfluidic chip is adjusted within the range of 0.1-10 μL / min, and the sealing performance of the membrane assembly and the smoothness of the fluid channel are verified by fluorescence tracing experiments.

[0017] Preferably, the biomimetic functional membrane continuous separation and purification system provided by the present invention includes an online monitoring system that employs an automated fractionation collector at the outlet of the microfluidic chip to analyze the purity and content of components in one or more effluents using UV detection, mass spectrometry, high-performance liquid chromatography-mass spectrometry (HPLC-MS), or ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). The present invention integrates an online monitoring system, such as a UV-Vis or mass spectrometry detector, to monitor the separation effect in real time and automatically adjust the system.

[0018] Preferably, in the biomimetic functional membrane continuous separation and purification system provided by the present invention, the intelligent control system is composed of a sensor network, a data acquisition module, an artificial intelligence algorithm and an execution control module; The sensor network includes installing pressure sensors, temperature sensors, flow sensors and / or concentration sensors at key points of the biomimetic functional membrane continuous separation and purification system to monitor process parameters in real time; The data acquisition module collects sensor data at a frequency of 10 Hz and transmits it to the central processing unit; Artificial intelligence algorithms, based on deep learning models, analyze the relationship between process parameters and separation results and predict optimal operating conditions; The execution control module automatically adjusts the system's parameters such as pressure, temperature, flow rate and elution conditions based on the algorithm output to achieve the best separation effect; the system also has a self-learning function, which continuously optimizes the control strategy based on historical operating data to improve separation efficiency.

[0019] Preferably, in the biomimetic functional membrane continuous separation and purification system provided by the present invention, liraglutide needs to pass through a sample pretreatment module before passing through the separation and purification system, including a supercritical CO2 extraction and ionic liquid collaborative separation process; an ionic liquid containing 1,2-dimethyl-3-ethoxymethylimidazolinium is prepared, liraglutide is mixed with it in a mass ratio of 1:2-6, and supercritical CO2 extraction is performed. After the extraction is completed, the solution containing different components is collected through a three-stage gradient decompression separator; the collected solution is diluted to 1-5 mg / ml and continuously separated and purified under pressure through the biomimetic functional membrane continuous separation and purification system.

[0020] The solubility of supercritical CO2 can be precisely controlled by adjusting pressure (7-25 MPa) and temperature, making it particularly suitable for separating heat-sensitive substances. Furthermore, CO2 is non-toxic, inert, and easily separable, leaving no organic solvent residue, thus complying with Good Manufacturing Practice (GMP) requirements. Supercritical CO2 can dissolve imidazolium ionic liquids (such as 1,2-dimethyl-3-ethoxymethylimidazolinium salt) but does not dissolve the ionic liquid itself, enabling efficient stripping of solutes. Imidazolinium ionic liquids (such as 1,2-dimethyl-3-ethoxymethylimidazolinium salt) exhibit high solubility for the hydrophobic peptide liraglutide and can inhibit peptide chain aggregation and reduce side reactions. Currently, the purification of liraglutide primarily relies on a two-step chromatography method: polystyrene divinylbenzene mass chromatography (alkaline ammonia-acetonitrile system) to remove hydrophobic impurities, and C18 reversed-phase chromatography (acidic acetonitrile-water system) to purify to a purity of >98%. The supercritical CO2 extraction and ionic liquid synergistic separation process for liraglutide can reduce solvent consumption and residue, and lower the risk of peptide stability; combined with the bionic functional membrane continuous separation and purification system, the separation selectivity is strong, reducing scale costs; combined with online monitoring, the structural integrity of the peptide can be tracked in real time, breaking through the three major bottlenecks of peptide selectivity, ionic liquid residue, and equipment economy, and has extremely strong practical economic benefits.

[0021] Preferably, the biomimetic functional membrane continuous separation and purification system provided by the present invention, wherein the base membrane surface is modified with hydrophobic groups, comprising placing the base membrane in a plasma treatment apparatus, introducing hydrophobic groups on the membrane surface, wherein the hydrophobic groups are octadecyl chains; Modifying the surface of the base membrane with cation exchange groups, including using an ultraviolet light-initiated graft polymerization method, immersing the membrane in an aqueous solution containing an organic acid and a photoinitiator, and irradiating the membrane with an ultraviolet lamp having a wavelength of 365 nm for 20 to 40 minutes under nitrogen protection to achieve graft polymerization of carboxyl groups, sulfonic acid groups, or nitro groups on the membrane surface to introduce cation exchange groups, wherein the organic acid includes acrylic acid and the photoinitiator includes benzophenone (1 wt %); Anion exchange groups or affinity ligands are modified on the surface of the base membrane, including by chemical grafting. The base membrane is immersed in a toluene solution containing an organic amine, a quaternary ammonium salt, or biotin, and reacted at 60°C to 100°C for 3 to 12 hours to introduce amino groups or biotin onto the membrane surface. The organic amine includes 3-aminopropyltriethoxysilane (APTES, 5wt%). This invention utilizes plasma treatment and chemical techniques to achieve functionalization of the membrane surface, enabling precise and controllable surface modification.

[0022] Preferably, the biomimetic functional membrane continuous separation and purification system provided by the present invention comprises a multilayer biomimetic functional membrane formed by connecting a plurality of multifunctional membranes in series, wherein the multifunctional membrane comprises a carboxyl group modified on the membrane surface for adsorbing alkaline substances; and / or an amino layer modified on the membrane surface for adsorbing acidic substances; and / or a crown ether group layer modified on the membrane surface for selectively complexing metal ions; and / or an unsaturated C18 fatty acid group layer modified on the membrane surface for enhancing affinity with liraglutide.

[0023] Preferably, the biomimetic functional membrane continuous separation and purification system provided by the present invention comprises a first layer comprising a polyvinylidene fluoride (PVDF)-COOH membrane with a pore size of 30 nm, a second layer comprising a polyethersulfone (PES)-crown ether group membrane with a pore size of 10 nm, and a third layer comprising a polyvinylidene fluoride (PVDF)-oleic acid (C18) membrane with a pore size of 5 nm.

[0024] Preferably, the biomimetic functional membrane continuous separation and purification system provided by the present invention comprises modifying the membrane surface with oleic acid (C18) groups, comprising preparing functionalized nanocellulose introduced with oleic acid (C18) and forming a functionalized nanofiber membrane; Functionalized nanocellulose with oleic acid was prepared by extracting cellulose from cotton fibers. The nanocellulose was dispersed in dimethyl sulfoxide (DMSO), and oleic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) / N-hydroxysuccinimide (NHS) were added at a molar ratio of 1:1.2:1.5. The mixture was reacted at 60°C for 6 hours for esterification. The modified nanocellulose was then blended with PVDF in a mass ratio of 1:4 in dimethyl carbonate to prepare functionalized nanocellulose via a phase inversion method. Functionalized nanofiber membranes are prepared by mixing functionalized nanocellulose introduced with oleic acid (C18) with one or more of polyethersulfone (PES), polyvinylidene fluoride (PVDF) or polysulfone (PSf) using electrospinning technology, with fiber diameters ranging from 10 to 200 nm.

[0025] The present invention introduces oleic acid (C18) functional groups into the surface of the nanofiber membrane, which has a strong affinity with liraglutide, thereby improving the functionality of the membrane. The nanofiber membrane is prepared using electrospinning technology, and the fiber diameter is controlled at 10-200 nm to ensure the membrane's efficient separation performance.

[0026] The beneficial effects of the present invention are as follows: by combining supercritical CO2 extraction with a multilayer biomimetic functional membrane continuous separation and purification system of a novel imidazolinium ionic liquid, the product stability, extraction rate and purity of liraglutide are significantly improved, so that the purity of the final target compound can be increased to 99.5%, which is 20-30% higher than that of traditional separation methods; the biomimetic functional membrane continuous separation and purification system composed of multilayer functional nanofiber membranes reduces the use of organic solvents and significantly reduces environmental pollution; the ion enrichment and separation device using concentration polarization effect and real-time calculation automation technology improve production capacity and production efficiency; the production cycle of the traditional batch process is shortened by 60-70%, realizing continuous production; the membrane surface is functionalized and modified by plasma treatment and chemical technology, thereby enhancing the mechanical stability of the membrane and having a high affinity for liraglutide; the system has a modular design, is easy to industrialize, and reduces energy consumption and simplifies operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1. Construction process of a biomimetic functional membrane continuous separation and purification system for liraglutide DETAILED DESCRIPTION

[0029] To further illustrate the present invention, examples are provided below. It should be noted that these examples are purely illustrative. These examples are provided to fully illustrate the significance and content of the present invention, but are not intended to limit the present invention to the scope of the embodiments. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Example 1 Liraglutide Pretreatment Module (Supercritical CO2 Extraction and Ionic Liquid Collaborative Separation Process) Example 1-1

[0030] Step 1: Synthesis and purification of novel imidazolinium ionic liquids First, a novel imidazolinium ionic liquid was synthesized. 10 g of 1,2-dimethylimidazole was mixed with 15 g of methyl ethyl ether chloride and reacted at 60°C under nitrogen for 8 hours. After the reaction, the mixture was cooled to room temperature and washed three times with 50 ml of ethyl acetate to remove any unreacted products. The resulting product was then dissolved in 20 ml of anhydrous ethanol, and 8 g of high-purity sodium perchlorate was added. The mixture was stirred and reacted at 40°C for 4 hours. After the reaction, the precipitated sodium chloride was filtered off, and the solvent was removed from the filtrate under reduced pressure to obtain a crude product. The crude product was dissolved in a small amount of dichloromethane and purified by silica gel column chromatography using dichloromethane / methanol (9:1 by volume) as the eluent. The eluate containing the desired product was collected and the solvent was evaporated under reduced pressure to obtain an ionic liquid with a purity greater than 99%. The resulting ionic liquid was dried under vacuum at 60°C for 24 hours to remove any residual solvent, yielding a colorless, transparent liquid with a yield of approximately 85%.

[0031] Step 2: Supercritical CO2 extraction and ionic liquid synergistic separation Liraglutide and a novel imidazolinium ionic liquid were mixed in a 1:2 mass ratio and placed in the extraction vessel of a supercritical CO2 extraction apparatus. The extraction vessel had a volume of 200 ml and a maximum pressure of 30 MPa. The extraction was carried out for 60 minutes at a CO2 flow rate of 8 ml / min, a temperature of 30°C, and a pressure of 22 MPa. During the extraction, the ionic liquid formed a complex with liraglutide, enhancing the solubility of the target compound in the supercritical CO2. After the extraction, the solution containing the target compound was collected in a vacuum separator. The separator was set at a temperature of 32°C and a pressure of 8 MPa. Under these conditions, the CO2 returned to its gaseous state and was discharged, leaving a liraglutide-rich solution. Example 1-2

[0032] Step 1: Optimized synthesis of novel imidazolinium ionic liquids To improve the purity and performance of the ionic liquid, the synthesis method was optimized. 1,2-dimethylimidazole (15 g) was mixed with 20 g of chloromethyl ethyl ether, and 5 ml of acetonitrile was added as solvent. The mixture was reacted at 100°C for 30 minutes in a microwave reactor (microwave power 300 W). After the reaction, the mixture was cooled to room temperature, and 100 ml of ethyl acetate was added to precipitate a white solid. The solid was collected by filtration and washed three times with 30 ml of ethyl acetate to obtain 1,2-dimethyl-3-ethoxymethylimidazolinium chloride. This chloride was dissolved in 30 ml of anhydrous ethanol, and 12 g of high-purity sodium perchlorate was added. The reaction was stirred at 50°C for 2 hours. After the reaction, the precipitated sodium chloride was removed by filtration, and the filtrate was purified by passing it through an activated carbon column to remove colored impurities. The purified solution was then distilled under reduced pressure to remove the solvent, yielding the ionic liquid. The product was vacuum-dried at 70°C for 48 hours to remove residual solvent and water, resulting in a colorless, transparent liquid with a yield of approximately 92% and a purity greater than 99.5%.

[0033] Step 2: Supercritical CO2 extraction and ionic liquid synergistic separation process Liraglutide was mixed with the previously synthesized high-purity ionic liquid in a 1:6 mass ratio and placed in the extraction vessel of a supercritical CO2 extraction apparatus. The extraction vessel had a capacity of 300 ml and a maximum pressure of 35 MPa. The extraction was performed for 90 minutes under conditions of a CO2 flow rate of 12 ml / min, a temperature of 35°C, and a pressure of 25 MPa. During the extraction process, the ionic liquid formed a specific interaction with liraglutide, significantly improving the solubility and selectivity of the target compound in supercritical CO2. After the extraction, the solution containing the different components was collected through a three-stage gradient vacuum separator. The first stage separator had a temperature of 35°C and a pressure of 15 MPa; the second stage separator had a temperature of 30°C and a pressure of 10 MPa; and the third stage separator had a temperature of 25°C and a pressure of 5 MPa. Precise control of the temperature and pressure of each stage of the separator allowed for the initial separation of the different components. Example 2 Preparation of functionalized nanocellulose with unsaturated C18 fatty acid functional groups

[0034] First, cellulose was extracted from cotton fibers. 100 g of bleached cotton fibers were added to 1000 ml of 64% sulfuric acid solution and heated in a water bath at 45°C with stirring for 60 minutes for acid hydrolysis. After the reaction, 4000 ml of ice water was added to dilute and terminate the reaction. The mixture was centrifuged (10,000 rpm for 10 minutes), and the precipitate was collected and washed with deionized water until neutral (pH ≈ 7). The resulting product was ultrasonically processed for 30 minutes (500 W power, 20 kHz frequency) to fully disperse the cellulose. Subsequently, the product was homogenized five times in a high-pressure homogenizer (150 MPa pressure) to obtain a nanocellulose suspension. Dynamic light scattering measurements revealed that the nanocellulose particles had diameters of 10-20 nm and lengths of 100-500 nm. The suspension was freeze-dried for 48 hours to obtain nanocellulose powder with a yield of approximately 40%.

[0035] 5 g of the prepared nanocellulose powder was dispersed in dimethyl sulfoxide (DMSO). Oleic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) / N-hydroxysuccinimide (NHS) were added at a molar ratio of 1:1.2:1.5, and the mixture was reacted at 60°C for 6 h for esterification. The modified nanocellulose was then blended with polyvinylidene fluoride (PVDF) in dimethyl carbonate at a mass ratio of 1:4 to prepare functionalized nanocellulose via a phase inversion method. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the successful introduction of functional groups. Elemental analysis revealed a functionalization degree (degree of substitution) of approximately 0.8, indicating that most of the cellulose hydroxyl groups were successfully modified. Example 3 Preparation of functionalized nanofiber membrane

[0036] 2g of the functionalized nanocellulose prepared in Example 2 was mixed with 8g of polyvinylidene fluoride (PVDF), and 90g of N,N-dimethylformamide (DMF) was added. The mixture was stirred at 60°C for 12 hours to obtain a uniform spinning solution. Functionalized nanofiber membranes were prepared using electrospinning. The solution was loaded into a 10ml syringe and attached to a stainless steel needle with an inner diameter of 0.8mm. The electrospinning voltage was set at 18kV, the distance between the needle tip and the receiving plate was 15cm, and the solution was fed at a rate of 1ml / h. Spinning was performed at a temperature of 25°C and a relative humidity of 40% for 4 hours. The resulting functionalized nanofiber membranes were vacuum dried at 60°C for 12 hours to remove residual solvent. Scanning electron microscopy revealed that the fiber diameters ranged from 10-180nm, with an average diameter of 60nm, meeting the control requirement of 10-200nm.

[0037] Through mechanical property testing, the tensile strength of the functionalized nanofiber membrane was 25 MPa and the elongation at break was 15%, which were significantly better than the pure PVDF membrane without functionalized nanocellulose (tensile strength 15 MPa, elongation at break 8%). Example 4 Construction of multilayer biomimetic functional membrane

[0038] Designing a multilayer biomimetic functional membrane structure, each layer has a specific pore size and surface chemical properties, which can selectively separate substances of different molecular weights and polarities. Depending on the separation requirements, different functionalized nanofiber membranes are selected and assembled in series.

[0039] First, three polymer materials—polyethersulfone (PES), polyvinylidene fluoride (PVDF), or polysulfone (PSf)—were selected as membrane matrix materials. A phase inversion method was used to prepare the base membrane. For the PES membrane, 15 g of PES powder was dissolved in 85 g of N-methylpyrrolidone (NMP) and stirred at 60°C for 12 hours to obtain a uniform casting solution. The casting solution was evenly coated onto a glass plate using a doctor blade to a thickness of 200 μm. The solution was then immediately immersed in a deionized water coagulation bath and allowed to soak at room temperature for 2 hours to complete the phase inversion. The resulting membrane was then immersed in deionized water for 24 hours to remove residual solvent, and then dried at 40°C for 12 hours to obtain the base PES membrane. By adjusting the polymer concentration, solvent composition, and coagulation bath conditions, four base membranes with pore sizes of 5 nm, 10 nm, 30 nm, and 50 nm were prepared. Scanning electron microscopy and bubble point analysis confirmed the uniform pore size distribution of each membrane, with a deviation within ±10%.

[0040] The prepared base membrane is surface modified using plasma treatment or chemical grafting techniques to improve its selectivity and anti-fouling properties. For example, oxygen plasma treatment is used for PES membranes. The membrane is placed in a plasma treatment apparatus and treated for 5 minutes at a power of 150 W, an oxygen flow rate of 30 sccm, and a pressure of 30 Pa to introduce hydrophobic groups such as octadecyl chains onto the membrane surface. For PVDF membranes, UV-induced graft polymerization is used. The membrane is immersed in an aqueous solution containing acrylic acid (20 wt%) and the photoinitiator benzophenone (1 wt%). Under nitrogen protection, the membrane is irradiated with a 365 nm UV lamp for 30 minutes to graft the acrylic acid onto the membrane surface and introduce carboxyl groups. For PSf membranes, chemical grafting is used. The membrane is immersed in a toluene solution containing 3-aminopropyltriethoxysilane (APTES, 5 wt%) and reacted at 80°C for 6 hours to introduce amino groups onto the membrane surface. Quaternary ammonium salts or biotin can also be introduced using the same method. X-ray photoelectron spectroscopy (XPS) and contact angle measurements confirmed the successful and uniform introduction of various functional groups onto the membrane surface. The water contact angle of the modified membrane decreased from 80-90° to 30-40°, indicating a significant improvement in hydrophilicity. Example 4-1

[0041] In this example, a four-layer functionalized membrane separation system was constructed. The first membrane layer was modified with hydrophobic groups (octadecyl chains) for adsorption of non-polar substances; the second membrane layer was modified with cation exchange groups (carboxyl groups) for adsorption of cations; the third membrane layer was modified with anion exchange groups (quaternary ammonium salts) for adsorption of strong anions; and the fourth membrane layer was modified with an affinity ligand (biotin) for specific adsorption of target molecules. These four membrane layers were sequentially placed on a custom membrane support, with a polytetrafluoroethylene gasket (50 mm inner diameter, 1 mm thickness) placed between each membrane layer to prevent leakage. The membrane support consisted of two plexiglass plates secured by bolts, with the upper plate having an inlet and the lower plate having an outlet. The effective filtration area of ​​the entire membrane assembly was 19.6 cm². Example 4-2

[0042] In this example, three layers of functionalized nanofiber membranes were used, each modified with a different selective group. The first layer was modified with carboxyl groups (-COOH) for alkaline adsorption; the second layer was modified with crown ether groups for selective metal ion complexation; and the third layer was modified with oleic acid (C18) groups to enhance affinity for liraglutide. These three membrane layers were sequentially placed on a custom membrane support, with a silicone gasket (60 mm inner diameter, 1.5 mm thickness) placed between each layer to ensure a tight seal. The membrane support consisted of two stainless steel plates secured by bolts. The upper plate contained the feed inlet and pressure sensor interface, while the lower plate housed the discharge port and temperature sensor interface. The total effective filtration area of ​​the entire membrane assembly was 28.3 cm². Example 5 Design and preparation of microfluidic chip

[0043] Using microfluidic chip technology, a biomimetic functional membrane is integrated into a microchannel to achieve continuous flow separation. First, the microfluidic chip structure was designed using computer-aided design software. The microfluidic chip adopts a sandwich structure. It consists of three layers of PDMS and two layers of glass, with multiple layers of biomimetic functional membranes sandwiched between them. The microfluidic chip measures 30 mm × 20 mm × 5 mm.

[0044] The chip consists of four parts: a liraglutide injection area, a membrane integration area, a separation area, a collection area, and a detection area. The injection area contains a micro-syringe pump and a sample storage tank. The membrane integration area has reserved membrane mounting holes for the subsequent installation of functionalized biomimetic functional membranes. The membrane integration area is designed as a multi-layer structure, for example, it can accommodate 3 to 4 layers of biomimetic functional membranes with different functions. The separation area is designed as a serpentine channel with a length of 20 cm, a width of 500 μm, and a depth of 200 μm to increase separation efficiency. The detection area contains various sensors and detectors. The microfluidic chip connects the various functional areas through microvalves and microchannels to achieve automatic sample processing and continuous flow separation. The flow rate of the microfluidic chip can be adjusted within the range of 0.1-10 μL / min, and the separation efficiency reaches over 95%.

[0045] A microfluidic chip mold was fabricated using soft lithography. A negative photoresist, SU-8 2100, was coated onto a silicon wafer to a thickness of 200 μm. The pattern was exposed through a mask and developed to obtain a microchannel mold. The mold was then replicated using polydimethylsiloxane (PDMS) to fabricate the microfluidic chip itself. A PDMS prepolymer and a crosslinker were mixed in a 10:1 mass ratio, degassed, and poured onto the mold. The mixture was then cured at 80°C for 2 hours. The cured PDMS was peeled from the mold to obtain a PDMS layer containing the microchannel structure. The PDMS layer was then bonded to a glass substrate using oxygen plasma activation to form a closed microfluidic channel. Example 6 Multilayer biomimetic functional membrane and microfluidic chip integrated system Example 6-1

[0046] The functionalized biomimetic membrane prepared in Example 4-1 was cut into 3 mm diameter discs and installed in the membrane integration area of ​​the microfluidic chip in sequence. For example, the installation order is: PES-octadecyl chain membrane with a pore size of 20 nm (first layer), PVDF-COOH membrane with a pore size of 10 nm (second layer), PSf-NH4 with a pore size of 10 nm (second layer), + membrane (third layer) and PES-biotin membrane with a pore size of 5 nm (fourth layer); A micro O-ring (2.5 mm inner diameter, 0.5 mm thickness) was placed between each membrane layer to prevent liquid leakage. Microbolts were used to secure the membrane assembly to ensure a tight seal. Fluorescence tracing experiments verified the membrane assembly's tightness and the smooth flow of the fluid channels. A sodium fluorescein solution (10 μg / ml) was injected into the chip via a microinjection pump at a flow rate of 5 μl / min. Fluorescence microscopy confirmed the absence of leaks and the smooth passage of fluid through all membrane layers, forming an integrated multilayer biomimetic functional membrane and microfluidic chip system. Example 6-2

[0047] The functionalized biomimetic membrane prepared in Example 4-2 was cut into 5 mm diameter discs and sequentially installed onto the membrane integration area of ​​the microfluidic chip. For example, the installation order might be: PVDF-COOH membrane with a pore size of 30 nm (first layer), PES-crown ether membrane with a pore size of 10 nm (second layer), and PVDF-oleic acid (C18) membrane with a pore size of 5 nm (third layer).

[0048] A micro O-ring (2.5 mm inner diameter, 0.5 mm thickness) was placed between each membrane layer to prevent liquid leakage. Microbolts were used to secure the membrane assembly to ensure a tight seal. Fluorescence tracing experiments verified the membrane assembly's tightness and the smooth flow of the fluid channels. A sodium fluorescein solution (10 μg / ml) was injected into the chip via a microinjection pump at a flow rate of 5 μl / min. Fluorescence microscopy confirmed the absence of leaks and the smooth passage of fluid through all membrane layers, forming an integrated multilayer biomimetic functional membrane and microfluidic chip system. Example 7 Continuous separation and purification process of a multilayer biomimetic functional membrane and microfluidic chip integrated system Example 7-1

[0049] The liraglutide solution collected in Example 1-1 was diluted to an appropriate concentration (typically 1-5 mg / ml) and pumped through the multilayer biomimetic functional membrane and microfluidic chip system at a constant flow rate (2 ml / min) using a high-pressure pump for continuous separation and purification. The system inlet pressure was controlled at 0.5 MPa to ensure smooth passage of the solution through the multilayer biomimetic functional membrane and microfluidic chip integrated system of Example 6-1. The solution first passed through the first hydrophobic membrane, where non-polar impurities were adsorbed; then through the second cation exchange membrane, where cationic impurities were adsorbed; then through the third anion exchange membrane, where strongly anionic impurities were adsorbed; and finally, through the fourth affinity membrane, where liraglutide was specifically adsorbed. After all the solution had passed through, each membrane was eluted sequentially with an appropriate eluent (typically a pH buffer or organic solvent), and the eluate containing the different components was collected. The fourth affinity membrane was eluted with a high-concentration competitive ligand solution (e.g., free biotin) to specifically release the target molecule. The entire separation process was performed at room temperature and took approximately 120 minutes.

[0050] An automated fractionation collector was installed at the outlet of the microfluidic chip. It automatically switched to collect different fractions based on signals from an online monitoring system. The collector consisted of eight micro-collection vials, each with a volume of 1 ml. The purity and content of each fraction were analyzed by high-performance liquid chromatography-mass spectrometry (HPLC-MS). HPLC conditions included an amino acid column with a mobile phase consisting of methanol / 0.1% formic acid in water (gradient elution, initial ratio 5:95, linearly increasing to 95:5 over 10 minutes), a flow rate of 0.3 ml / min, a column temperature of 25°C, and a detection wavelength of 254 nm. Mass spectrometry conditions included an electrospray ionization source, alternating positive and negative ion modes, a spray voltage of ±3.0 kV, a capillary temperature of 300°C, and a scan range of m / z 100-1500. The results confirmed a purity of 92.5% for the target compound, with a recovery of approximately 72%. Example 7-2

[0051] The liraglutide solution collected in Example 1-2 was pumped through the multilayer biomimetic functional membrane and microfluidic chip integrated system of Example 6-2 at a constant flow rate (3 ml / min) using a high-pressure pump. The system inlet pressure was controlled at 0.8 MPa to ensure smooth passage of the solution through all membrane layers. The solution sequentially passed through components with different properties, where they were selectively adsorbed or repelled by the corresponding functional layers. In particular, the third membrane layer, containing oleic acid (C18) groups, exhibited a high affinity for liraglutide, enabling efficient separation. During the separation process, the system temperature was maintained at 30°C to maintain optimal membrane performance. After separation, each membrane layer was sequentially eluted with an appropriate eluent (pH buffer, organic solvent, or ionic strength gradient solution), and the eluents containing the different components were collected. The entire separation process lasted approximately 180 minutes and could operate continuously for over 8 hours without membrane replacement.

[0052] The eluates from each layer of the multilayer biomimetic functional membrane system were collected and analyzed for purity and content of each component using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). UPLC conditions included an amino acid column with a mobile phase consisting of methanol / 0.1% formic acid in water (gradient elution, initial ratio 60:40, linearly increasing to 95:5 over 15 minutes), a flow rate of 0.4 ml / min, a column temperature of 40°C, and a detection wavelength of 280 nm. Mass spectrometry conditions included an electrospray ionization source, alternating positive and negative ion modes, a spray voltage of ±3.5 kV, a capillary temperature of 350°C, and a scan range of m / z 100-2000. The analytical results confirmed a purity of 99.5% for the target compound, with a recovery of approximately 93%. Compared with traditional separation methods, this protocol reduces organic solvent usage by over 90% and increases production efficiency by 80%. Example 8 System Performance Evaluation and Optimization

[0053] The system's performance was evaluated by comparing the separation results of traditional separation methods (such as liquid-liquid extraction and column chromatography) with those of this system. Evaluation metrics included productivity improvement, solvent usage reduction, and product purity improvement. Experimental results showed that compared with traditional batch processes, this system increased productivity by 75%, reduced solvent usage by 85%, and achieved product purity exceeding 98%.

[0054] To further optimize system performance, the following parameters can be adjusted: number of membrane layers (3-5 layers), membrane pore size (5-50nm), flow mode (cross flow or straight flow), operating pressure (0.1-1.0MPa), etc. Through orthogonal experimental design, the optimal operating conditions are determined to achieve optimal system performance.

[0055] To further optimize system performance, response surface methodology was used to design experiments to examine the effects of flow rate (0.5-5 μl / min), temperature (20-40°C), pH (5-9), and membrane pore size on separation. Mathematical model analysis determined the optimal operating conditions to be: a flow rate of 2.5 μl / min, a temperature of 28°C, and a pH of 6.8, achieving both optimal system separation efficiency and product purity (99.5%). Example 9 Integration of Intelligent Control System

[0056] In the present embodiment, the biomimetic functional membrane continuous separation and purification system integrates an online monitoring system, such as UV-Vis or mass spectrometer detector, to monitor the separation effect in real time and automatically adjust. A micro-UV-Vis detector is connected at the outlet of the microfluidic chip, with a wavelength range of 190-800nm, which can monitor 8 different wavelengths simultaneously. The concentration of each component is calculated in real time according to the UV absorption value through a pre-established standard curve. At the same time, a micro-mass spectrometer detector is integrated in the system, using an electrospray ionization source with a mass range of m / z 50-2000. Through mass spectrometry data, the molecular weight and structural information of each component can be confirmed in real time. The monitoring data is transferred to a computer via a data acquisition card, and data processing and analysis are performed using independently developed software. The software has automatic peak recognition, quantitative analysis and parameter optimization functions, and can automatically adjust separation conditions such as flow rate, temperature and eluent composition according to the monitoring results to achieve the best separation effect.

[0057] To ensure an efficient and stable operating environment, this embodiment integrates an intelligent control system. The system consists of a sensor network, a data acquisition module, an artificial intelligence algorithm and an execution control module. Pressure sensors, temperature sensors, flow sensors and concentration sensors are installed at key points of the supercritical CO2 extraction device and the multi-layer bionic functional membrane system to monitor process parameters in real time. The data acquisition module collects sensor data at a frequency of 10Hz and transmits it to the central processing unit. The artificial intelligence algorithm is based on a deep learning model to analyze the relationship between process parameters and separation effects and predict the optimal operating conditions. The execution control module automatically adjusts the system's parameters such as pressure, temperature, flow and elution conditions according to the algorithm output to achieve the best separation effect. The system also has a self-learning function, which can continuously optimize the control strategy based on historical operating data to improve separation efficiency.

[0058] The control system, based on a PLC (Programmable Logic Controller) platform, automatically adjusts pump speed, valve switching, and eluent composition through pre-set programs to maintain optimal separation conditions. The system is also equipped with an online UV detector to monitor changes in the composition of the outlet liquid in real time. Based on the detection results, it automatically switches collection containers to achieve automated separation and collection of different components. The entire system features a user-friendly interface, allowing parameter settings and status monitoring via the touchscreen, significantly reducing the need for manual operation.

[0059] Through the above steps, the integrated biomimetic functional membrane continuous separation and purification system for liraglutide provided in this embodiment combines supercritical CO2 with the efficient separation technology of a novel ionic liquid, successfully achieving efficient and simultaneous separation of multiple components. This system leverages the selective adsorption properties of multi-layer functionalized nanofiber membranes, integrated with a microfluidic chip, and combined with the synergistic effects of supercritical CO2 extraction and ionic liquids to significantly improve separation efficiency and product purity. The system enables continuous production, increasing production capacity by 50-100%, reducing solvent usage by over 70%, and is easily scalable and automated.

[0060] This system is particularly suitable for the separation and purification of liraglutide, has obvious advantages in continuous production, and provides a new technical solution for the separation of raw materials or extracts.

[0061] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A biomimetic functional membrane continuous separation and purification system for liraglutide, characterized in that: The system is used for continuous separation and purification of liraglutide at 2–8°C. It integrates a multilayer biomimetic functional membrane into a microchannel to form a microfluidic chip, and integrates an online monitoring system to monitor the separation effect in real time. The separation strategy is optimized through an intelligent control system. Each layer of the multilayer biomimetic functional membrane has a specific pore size and surface chemical properties, allowing for selective separation of substances with different molecular weights, polarities, and biological characteristics. The preparation method includes: 1) Selecting one or more of polyethersulfone (PES), polyvinylidene fluoride (PVDF) or polysulfone (PSf) as the membrane matrix material and preparing the base membrane by phase inversion method; 2) using plasma treatment or chemical grafting technology to modify the surface of the base membrane to form a multifunctional membrane, thereby improving the selectivity and anti-pollution ability of the membrane; The multilayer biomimetic functional membrane is formed by 3 to 5 layers of multifunctional membranes connected in series, and the multifunctional membrane includes modifying hydrophobic groups on the surface of the base membrane for adsorbing non-polar substances; and / or modifying cation exchange groups on the surface of the base membrane for adsorbing cations; and / or modifying strong anion exchange groups on the surface of the base membrane for adsorbing strong anions; and / or modifying affinity ligands on the surface of the base membrane for specifically adsorbing target molecules.

2. The biomimetic functional membrane continuous separation and purification system according to claim 1, characterized in that: The microfluidic chip adopts a sandwich structure design, consisting of three layers of polydimethylsiloxane (PDMS) and two layers of glass, with multiple layers of biomimetic functional membranes sandwiched in between; the chip consists of an injection area, a membrane integration area, a separation area, a collection area, and a detection area; the injection area contains a micro-injection pump and a sample storage pool; the membrane integration area accommodates 3 or more layers of different multifunctional membranes; the separation area is designed as a serpentine channel to increase separation efficiency; the detection area contains a variety of sensors and detectors; the microfluidic chip connects various functional areas through microvalves and microchannels to achieve automatic processing of samples and continuous flow separation.

3. The biomimetic functional membrane continuous separation and purification system according to claim 1, characterized in that: The flow rate of the microfluidic chip is adjusted within the range of 0.1-10 μL / min, and the sealing of the membrane assembly and the smoothness of the fluid channel are verified by fluorescence tracing experiments.

4. The biomimetic functional membrane continuous separation and purification system according to claim 1, characterized in that: The online monitoring system is configured with an automatic fractionation collector at the outlet of the microfluidic chip to analyze the purity and content of components in one or more effluents by ultraviolet detection, mass spectrometry, high performance liquid chromatography-mass spectrometry (HPLC-MS), or ultra performance liquid chromatography-mass spectrometry (UPLC-MS).

5. The biomimetic functional membrane continuous separation and purification system according to claim 1, characterized in that: The intelligent control system consists of a sensor network, a data acquisition module, an artificial intelligence algorithm and an execution control module; The sensor network includes pressure sensors, temperature sensors, flow sensors and / or concentration sensors installed at key points of the biomimetic functional membrane continuous separation and purification system to monitor process parameters in real time; The data acquisition module collects sensor data at a frequency of 10 Hz and transmits it to the central processing unit; The artificial intelligence algorithm is based on a deep learning model to analyze the relationship between process parameters and separation effect and predict the optimal operating conditions; The execution control module automatically adjusts the system's parameters such as pressure, temperature, flow rate and elution conditions based on the algorithm output to achieve the best separation effect; the system also has a self-learning function, which continuously optimizes the control strategy based on historical operation data to improve separation efficiency.

6. The biomimetic functional membrane continuous separation and purification system according to claim 1, characterized in that: Before passing through the separation and purification system, liraglutide passes through a sample pretreatment module, including a supercritical CO2 extraction and ionic liquid collaborative separation process; an ionic liquid containing 1,2-dimethyl-3-ethoxymethylimidazolinium is prepared, liraglutide is mixed with the ionic liquid in a mass ratio of 1:2-6, and supercritical CO2 extraction is performed. After the extraction is completed, a solution containing different components is collected through a three-stage gradient decompression separator; the collected solution is diluted to 1-5 mg / ml and continuously separated and purified under pressure through the biomimetic functional membrane continuous separation and purification system.

7. The biomimetic functional membrane continuous separation and purification system according to claim 1, characterized in that: The method of modifying the surface of the base membrane with hydrophobic groups comprises placing the base membrane in a plasma treatment apparatus and introducing hydrophobic groups on the surface of the membrane, wherein the hydrophobic groups are octadecyl chains; The modification of the cation exchange groups on the surface of the base membrane comprises adopting an ultraviolet light-induced graft polymerization method, immersing the membrane in an aqueous solution containing an organic acid and a photoinitiator, and irradiating the membrane with an ultraviolet lamp with a wavelength of 365 nm for 20 to 40 minutes under nitrogen protection to achieve graft polymerization of carboxyl groups, sulfonic acid groups or nitro groups on the membrane surface to introduce cation exchange groups, wherein the organic acid comprises acrylic acid and the photoinitiator comprises benzophenone (1 wt %); The method of modifying the surface of the base membrane with anion exchange groups or affinity ligands includes using a chemical grafting method to immerse the base membrane in a toluene solution containing an organic amine, a quaternary ammonium salt or biotin, reacting at 60°C to 100°C for 3 to 12 hours, and introducing amino groups or biotin on the membrane surface. The organic amine includes 3-aminopropyltriethoxysilane (APTES, 5wt%).

8. The biomimetic functional membrane continuous separation and purification system according to claim 1, characterized in that: The multilayer biomimetic functional membrane is formed by connecting multiple multifunctional membranes in series. The multifunctional membrane includes a carboxyl group modified on the membrane surface for adsorbing alkaline substances; and / or an amino group modified on the membrane surface for adsorbing acidic substances; and / or a crown ether group layer modified on the membrane surface for selectively complexing metal ions; and / or an unsaturated C18 fatty acid group layer modified on the membrane surface for enhancing affinity with liraglutide.

9. The biomimetic functional membrane continuous separation and purification system according to claim 8, characterized in that: The first layer is a polyvinylidene fluoride (PVDF)-COOH membrane with a pore size of 30 nm, the second layer is a polyethersulfone (PES)-crown ether group membrane with a pore size of 10 nm, and the third layer is a polyvinylidene fluoride (PVDF)-oleic acid (C18) with a pore size of 5 nm.

10. The biomimetic functional membrane continuous separation and purification system according to claim 9, characterized in that: Modifying the membrane surface with oleic acid (C18) groups, including preparing functionalized nanocellulose introduced with oleic acid (C18) and forming a functionalized nanofiber membrane; The functionalized nanocellulose introduced with oleic acid (C18) is prepared by extracting cellulose from cotton fibers, dispersing the nanocellulose in dimethyl sulfoxide (DMSO), adding oleic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) / N-hydroxysuccinimide (NHS) at a molar ratio of 1:1.2:1.5, reacting at 60°C for 6 hours for esterification modification, and blending the modified nanocellulose with PVDF in a mass ratio of 1:4 in dimethyl carbonate to prepare the functionalized nanocellulose by a phase inversion method; The functionalized nanofiber membrane is prepared by mixing functionalized nanocellulose introduced with oleic acid (C18) with one or more of polyethersulfone (PES), polyvinylidene fluoride (PVDF) or polysulfone (PSf) using electrospinning technology, and the fiber diameter is 10-200 nm.

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