Antibacterial nanofiber hemodialysis membrane and preparation method thereof

Abstract

The invention discloses an antibacterial nanofiber hemodialysis membrane and a preparation method thereof, and relates to the technical field of dialysis membranes, and the preparation method comprises the following steps: mixing a chitosan derivative, heparin, dopamine, an unsaturated monomer and an initiator in a DMF / phosphate buffer mixed solution to obtain a surface treating agent; taking the polyethersulfone nanofiber membrane as a supporting layer, dipping in a surface treating agent, and performing UV irradiation to form a functional layer, thereby obtaining the dialysis membrane. The preparation method comprises the following steps: compounding phenanthroline cerium triacrylate hybridized CeO2 with N-vinyl pyrrolidone, sodium p-styrenesulfonate and lauryl methacrylate to obtain an unsaturated monomer, compounding the unsaturated monomer with a chitosan derivative, heparin and dopamine to prepare a surface treating agent, impregnating a polyether sulfone nanofiber membrane, and carrying out irradiation curing to form a functional layer. The prepared hemodialysis membrane has efficient anticoagulation and broad-spectrum antibacterial properties, high permeability, low protein adsorbability and long-term stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dialysis membrane, and particularly relates to an antibacterial nanofiber hemodialysis membrane and a preparation method thereof. BACKGROUND

[0002] Due to the decline of kidney function of patients with chronic kidney disease, endogenous and exogenous toxins in the body cannot be normally discharged, resulting in accumulation of toxins in the blood, which can affect the normal function of various tissues or organs, thereby causing uremia syndrome. Hemodialysis is an extracorporeal blood purification technology, which removes various harmful and redundant metabolic waste and excessive electrolytes in the body through diffusion, convection and the like, so as to purify blood and correct water electrolyte and acid-base balance. During the dialysis process, blood and dialysate contact and exchange substances in the dialyzer by means of a semi-permeable membrane and a concentration gradient, so that metabolic waste and excessive electrolytes in the blood move to the dialysate, and calcium ions and bases in the dialysate move to the blood. Hemodialysis membrane is the core component of hemodialysis device and plays a key role in the process of hemodialysis; mainstream materials thereof include cellulose, polysulfone, polyether sulfone, polymethyl methacrylate, ethylene-vinyl alcohol copolymer, polyacrylonitrile and the like. Hemodialysis center is a high-risk place for hospital infection (especially blood-borne infectious diseases); dialysis patients often have characteristics such as immune system disorder and low immune function, and are prone to hospital infection and inflammatory reaction. Therefore, an antibacterial nanofiber hemodialysis membrane and a preparation method thereof are proposed. SUMMARY

[0003] The present application aims to provide an antibacterial nanofiber hemodialysis membrane and a preparation method thereof to solve the problems in the background.

[0004] In order to solve the above technical problems, the present application provides the following technical scheme: an antibacterial nanofiber hemodialysis membrane, comprising a support layer and a functional layer. Further, the support layer is a polyether sulfone nanofiber membrane.

[0005] Further, the functional layer is formed by impregnating the polyether sulfone nanofiber membrane with a surface treatment agent and then solidifying.

[0006] Further, the surface treatment agent comprises components: sulfonated chitosan, heparin, dopamine, unsaturated monomer and initiator.

[0007] Further, the unsaturated monomer comprises one or more of methyl methacrylate, vinyltriethoxysilane, N-isopropyl acrylamide, methacrylic acid, styrene, N-vinyl pyrrolidone, sodium p-styrenesulfonate, lauryl methacrylate and acrylic acid-rare earth derivative.

[0008] Further, the acrylic acid-rare earth derivative is a cerium phenanthroline triacrylate hybrid CeO2.

[0009] In the technical scheme, the support layer is a polyether sulfone nanofiber membrane prepared by electrospinning, has high porosity, and the pores are interconnected, which can significantly improve the water flux and promote the diffusion and removal of middle-molecular toxins; and has good acid and alkali resistance, high temperature resistance, oxidation resistance and biocompatibility, and has certain mechanical strength.

[0010] A preparation method of an antibacterial nanofiber hemodialysis membrane, comprising the following processes: The sulfonated chitosan, heparin, dopamine, unsaturated monomer and initiator are mixed in a DMF / phosphate buffer solution mixture to obtain a surface treatment agent. The polyether sulfone nanofiber membrane is taken as the support layer, the surface treatment agent is immersed, UV irradiation is performed, a functional layer is formed, and a dialysis membrane is obtained.

[0011] Further, the surface treatment agent comprises the following mass components: 5-8 parts of sulfonated chitosan, 3-5 parts of heparin, 2-3 parts of dopamine, 20-40 parts of unsaturated monomer, and 1-2 parts of photoinitiator.

[0012] Further, the unsaturated monomer comprises the following mass components: 8-10 parts of N-vinyl pyrrolidone, 4-6 parts of sodium p-styrenesulfonate, 1-2 parts of cerium phenanthroline triacrylate hybrid CeO2, and 2.4-3.0 parts of lauryl methacrylate.

[0013] Further, the concentration of the surface treatment agent is 15-20 wt%. The volume ratio of the two in the DMF / phosphate buffer solution (PBS, pH 7.4) mixture is 6:4.

[0014] Further, the photoinitiator is benzophenone.

[0015] In the technical scheme, the sulfonated chitosan provides negative charge anticoagulation and antibacterial groups, has the effects of anticoagulation and inhibition of bacterial adhesion. The heparin cooperates with the sulfonic acid group of the sulfonated chitosan to enhance the anticoagulation effect and improve the anti-Xa activity. The dopamine (hydrochloride) acts as an adhesion promoter, forms hydrogen bonds / π-π stacking with the support layer through the catechol group, and enhances the bonding force between the functional layer and the support layer.

[0016] N-vinylpyrrolidone as a hydrophilic monomer can reduce protein adsorption, indirectly reducing bacterial adhesion. Sodium p-styrenesulfonate can increase the surface negative charge density, interfere with the bacterial cell membrane potential, inhibit metabolism, further improve the anticoagulant property, and improve the clearance rate of middle molecular toxins (such as β2-microglobulin). Lauryl methacrylate as a hydrophobic regulator, regulates the surface microphase separation, balances the hydrophilicity, prevents excessive swelling, and maintains the stability of the membrane structure. Its hydrophobic long chain (C12) inserts into the bacterial membrane, causing structural collapse and improving the antibacterial ability of the functional layer. Ce-TAP@CeO2 as an antibacterial / antioxidant multifunctional filler improves the bacteriostatic rate and ROS clearance rate of the functional layer. The photoinitiator benzophenone initiates the free radical polymerization of the unsaturated monomer to form a functional layer with an interpenetrating three-dimensional network structure.

[0017] Further, in the dipping process, the dipping ratio of polyether sulfone nanofiber membrane and surface treatment agent is 1g:10-15mL; the dipping time is 5-10min; and the extrusion roller pressure is 0.1-0.3MPa.

[0018] Further, the process conditions of UV irradiation are: wavelength 365nm, light intensity 5-8mW / cm 2 , irradiation time 5-10min; and then wavelength 365nm, light intensity 12-18mW / cm 2 , irradiation time 12-20min.

[0019] Further, after UV irradiation, drying is performed, and the thickness of the functional layer after drying is 20%-30% of the thickness of the support layer.

[0020] In the above technical solution, the catechol group of dopamine forms a hydrogen bond with the sulfone group (-SO 2- ) of the PES nanofiber, and UV curing causes the unsaturated monomer (such as NVP, SSS) to graft copolymerize on the PES surface. The treatment agent penetrates into the fiber membrane (about 10-20μm deep), forming a hydrophilic-antibacterial-anticoagulant multifunctional layer that gradually changes from the inside to the outside, which has good biocompatibility. The micropores (1-2μm) of the surface functional layer can retain the high porosity of the support layer, improve the water flux, and optimize the permeability of the prepared dialysis membrane. The formation of the UV crosslinked network can prevent the dissolution of components, improve the mechanical strength of the membrane body, and the prepared dialysis membrane has good durability.

[0021] Further, the sulfonated chitosan is prepared by the following process: Dissolve citric acid in deionized water, add chitosan, heat to 58-62℃, and react for 150-200min; add water, adjust the system pH to neutral, precipitate with acetone, and wash with ethanol to obtain citric acid-chitosan; The glycidol is mixed with the citric acid-chitosan, and reacted at 48-53 ℃ for 8-12 h; the reaction is terminated by adding ice water after cooling to room temperature; precipitated by adding acetone, filtered, washed; redissolved in acetic acid solution, dialyzed, and vacuum dried to obtain hydroxypropyl chitosan; The hydroxypropyl chitosan is mixed with DMF / NMP mixed solvent at 0-5 ℃, and a sulfonating agent is added, and reacted at 25-40 ℃ for 30-180 min; the residual chlorosulfonic acid is quenched by adding 5% NaHCO3 solution, and then the pH is adjusted to 3, dialyzed, and vacuum dried to obtain sulfonated chitosan.

[0022] Further, the mass ratio of chitosan to citric acid is 1: (1.2-1.3) ; The ratio of citric acid to deionized water is 10-15 g / 100 mL; The chitosan is added in the form of a solution, and the concentration is 2 wt%; the solvent is 1 wt% acetic acid solution.

[0023] Further, the mass ratio of citric acid-chitosan to glycidol is 10: (4-6) ; 0.1% triethylamine can be added as a catalyst in the system.

[0024] Further, the sulfonating agent is a mixture of chlorosulfonic acid and pyridine, and the molar ratio is 1:1; The mass ratio of hydroxypropyl chitosan to sulfonating agent is 10: (1.5-2.3) ; The ratio of hydroxypropyl chitosan to DMF / NMP mixed solvent is 10-15 g / 100 mL; In the DMF / NMP mixed solvent, the volume ratio of DMF (N,N-dimethylformamide) to NMP (N-methyl pyrrolidone) is 1:1.

[0025] In the above technical solution, the carboxyl group in citric acid reacts with the amino group in chitosan to form a amide, and the carboxyl group and the hydroxyl group are retained, forming a polycarboxyl chitosan, which is denoted as citric acid-chitosan. The epoxy group in glycidol opens and reacts with the active groups of the prepared citric acid-chitosan, introducing a hydrophilic hydroxypropyl side chain, and the product is denoted as hydroxypropyl chitosan. Triethylamine is used as a catalyst to promote the ring-opening of the epoxy group and inhibit side reactions. The prepared hydroxypropyl chitosan is mixed with a sulfonating agent, and chlorosulfonic acid (HClSO3) and pyridine form a mild sulfonation system, which attacks the hydroxyl group (-OH) in the hydroxypropyl chitosan to generate a sulfonic acid group (-SO3H), obtaining sulfonated chitosan.

[0026] The sulfonic acid group (-SO3H) in the sulfonated chitosan provides a negative charge, which can simulate the structure of heparin, repel platelets and plasma protein adsorption through negative charge, thereby inhibiting the activation of blood coagulation factors and improving the anticoagulation effect of the dialysis membrane. The residual amino group (-NH3+ ) through electrostatic adsorption, electrostatic interaction with the bacterial cell membrane, destroy its integrity, achieve the antibacterial property of the dialysis membrane. At the same time, the sulfonic acid group and the hydroxyl group have hydrophilicity, which can synergistically enhance the hydrophilicity of the surface of the functional layer, reduce protein adsorption, inhibit bacterial adhesion and biofilm formation.

[0027] Further, the cerium triphenanthroline acrylate hybrid CeO2 (Ce-TAP@CeO2) is prepared by the following process: Dissolve the acrylic acid in dimethyl sulfoxide, add the nano cerium oxide and 1,10-phenanthroline in turn, heat to 50-60℃, react for 1-2h; reduce pressure and filter, wash with ethanol for 2-3 times, recrystallize with acetone / ethyl ether, vacuum dry at 40-50℃ for 6-12h to obtain the cerium triphenanthroline acrylate hybrid CeO2.

[0028] Further, the mass ratio of the nano cerium oxide (CeO2), acrylic acid and 1,10-phenanthroline is 1: (0.35-0.45): (0.5-0.7); The particle size of the nano cerium oxide is 20-50nm.

[0029] Further, the amount of dimethyl sulfoxide (DMSO) is 14.3-16.7 times the mass of the acrylic acid.

[0030] Further, the acrylic acid contains 0.05wt% polymerization inhibitor 4-methoxyphenol, and the reaction is carried out under nitrogen protection; The nano cerium oxide is pretreated before being added: ultrasonic dispersion for 30min at a power of 300W to avoid agglomeration.

[0031] In the above technical solution, the nitrogen atom of 1,10-phenanthroline (Phen) coordinates with the Ce 3+ / Ce 4+ of the surface of CeO2, and the carboxyl group (-COOH) of acrylic acid forms a chelate bond with the Ce 3+ of the surface of CeO2 to generate a ternary complex, forming Ce-O-CO-CH=CH2, which is loaded on the surface of the nano cerium dioxide to form Ce-TAP@CeO2, which is recorded as cerium triphenanthroline acrylate hybrid CeO2, and has good adsorption for urea and the like. The carbon-carbon double bond (C=C) of the acrylic acid is reserved to provide active sites for subsequent polymerization.

[0032] Compared with the acrylic acid-rare earth ion derivative (such as cerium triphenanthroline acrylate), the cerium triphenanthroline acrylate hybrid CeO2 introduces the hybrid ion CeO2, and the oxygen vacancies (Ce 3+ / Ce 4+), filled with Phen and acrylic acid, can reduce surface defects and enhance its stability; while the residual oxygen vacancies can catalyze the generation of ROS (·OH, H2O2), and occur redox cycle, inhibit the formation of biofilm, enhance the antibacterial property; neutralize free radicals, reduce oxidative stress. At the same time, the nano CeO2 dispersed in the polymer network of the functional layer can effectively improve the strength of the membrane body.

[0033] Compared with the prior art, the application has the following beneficial effects: The preparation method of the antibacterial nanofiber hemodialysis membrane described in the application uses N-vinyl pyrrolidone, sodium p-styrenesulfonate, cerium phthalocyanine triacrylate CeO2 hybrid, and lauryl methacrylate as unsaturated monomers, and sulfonated chitosan, heparin, and dopamine are compounded to prepare a surface treatment agent, which is impregnated into a polyether sulfone nanofiber membrane, and a functional layer is formed after irradiation and curing, and the prepared hemodialysis membrane has high efficient anticoagulation and broad-spectrum antibacterial property, high permeability, low protein adsorption, and long-term stability. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0035] In the following detailed description, Support layer: polyether sulfone nanofiber membrane prepared by electrospinning technology, porosity 60%, thickness 50 mu m, fiber diameter 300-400 nm; Chitosan: degree of deacetylation 95%, viscosity: 100-200 mPa·s; Chitosan is added in the form of a solution, and the concentration is 2wt%; the solvent is 1wt% acetic acid solution; The particle size of nano cerium oxide is 20-50 nm; Before adding nano cerium oxide, ultrasonic dispersion is performed at 300W power for 30min; The cerium phthalocyanine triacrylate CeO2 hybrid is ultrasonically dispersed at 300W power for 5min before adding the treatment agent.

[0036] Embodiment 1: A preparation method of an antibacterial nanofiber hemodialysis membrane, comprising the following processes: Step 1, citric acid is dissolved in deionized water, chitosan is added and mixed, and the temperature is raised to 58℃, and the reaction is carried out for 200 min; add water, adjust the pH of the system to neutral, precipitate with acetone, wash with ethanol, and obtain citric acid-chitosan; the mass ratio of chitosan to citric acid is 1:1.2; the ratio of citric acid to deionized water is 10g / 100mL; Mix citric acid-chitosan and glycidol, and react at 48℃ for 12h; cool to room temperature, add ice water to terminate the reaction; add acetone to precipitate, filter, wash; redissolve in acetic acid solution, dialysis, vacuum drying, to obtain hydroxypropyl chitosan; the mass ratio of citric acid-chitosan to glycidol is 10:4; 0.1% triethylamine is added as a catalyst in the system; Mix hydroxypropyl chitosan and DMF / NMP mixed solvent at 3℃, add sulfonating reagent, and react at 25℃ for 180 min; add 5% NaHCO3 solution to quench residual chlorosulfonic acid, and then adjust the pH to 3, dialysis, vacuum drying, to obtain sulfonated chitosan; the sulfonating reagent is a mixture of chlorosulfonic acid and pyridine, with a molar ratio of 1:1; the mass ratio of hydroxypropyl chitosan to sulfonating reagent is 10:1.5; the ratio of hydroxypropyl chitosan to DMF / NMP mixed solvent is 10g / 100mL; the volume ratio of DMF to NMP in the DMF / NMP mixed solvent is 1:1; Step 2, acrylate is dissolved in dimethyl sulfoxide, and nano cerium oxide and 1,10-phenanthroline are added in sequence, the temperature is raised to 50℃, and the reaction is carried out for 2h; vacuum filtration is used, and ethanol is used for washing twice, and acetone / ether recrystallization is used, and vacuum drying is carried out at 40℃ for 12h, to obtain triacrylic acid phenanthroline cerium hybrid CeO2; the mass ratio of nano cerium oxide, acrylate and 1,10-phenanthroline is 1:0.35:0.5; the amount of dimethyl sulfoxide is 14.3 times the mass of acrylate; acrylate contains 0.05wt% polymerization inhibitor 4-methoxyphenol, and the reaction is carried out under nitrogen protection; Step 3, dissolve the sulfonated chitosan in the DMF / phosphate buffer mixture, dissolve the heparin in the phosphate buffer, mix the two under light protection, stir at a speed of 200 rpm for 30 min; add dopamine (hydrochloride) and stir for 10 min; add the unsaturated monomer under the protection of nitrogen atmosphere and stir for 120 min; add the photoinitiator and stir for 30 min; add the DMF / phosphate buffer mixture to obtain a surface treatment agent with a concentration of 15 wt%; then pass through a 0.45 μm filter membrane and adjust the pH to 6.5; the surface treatment agent comprises the following mass components: 5 parts of sulfonated chitosan, 3 parts of heparin, 2 parts of dopamine, 20 parts of unsaturated monomer, and 1 part of photoinitiator benzophenone; the unsaturated monomer comprises the following mass components: 8 parts of N-vinyl pyrrolidone, 4 parts of sodium p-styrene sulfonate, 1 part of cerium phthalocyanine triacrylate CeO2, and 2.4 parts of lauryl methacrylate; the volume ratio of DMF to phosphate buffer (PBS, pH 7.4) is 6:4; the two additions of the DMF / phosphate buffer mixture are the same; Step 4, take the polyether sulfone nanofiber membrane as a support layer, immerse the surface treatment agent, and the immersion ratio of the polyether sulfone nanofiber membrane to the surface treatment agent is 1 g:10 mL; the immersion time is 5 min; the pressure of the extrusion roller is 0.1 MPa; UV irradiation, the process conditions of UV irradiation are: under the protection of nitrogen atmosphere, wavelength 365 nm, light intensity 8 mW / cm², and irradiation time 5 min; then wavelength 365 nm, light intensity 15 mW / cm 2 , and irradiation time 12 min; a functional layer is formed to obtain a dialysis membrane.

[0037] Example 2: A preparation method of an antibacterial nanofiber hemodialysis membrane, comprising the following processes: Step 1, dissolve citric acid in deionized water, add chitosan, heat to 60°C, and react for 180 min; add water to adjust the pH of the system to neutral, precipitate with acetone, wash with ethanol, and obtain citric acid-chitosan; the mass ratio of chitosan to citric acid is 1:1.25; the ratio of citric acid to deionized water is 12 g / 100 mL; mix citric acid-chitosan and glycidol, react at 50°C for 10 h; cool to room temperature, add ice water to terminate the reaction; precipitate with acetone, filter, and wash; redissolve in acetic acid solution, dialyze, and vacuum dry to obtain hydroxypropyl chitosan; the mass ratio of citric acid-chitosan to glycidol is 10:5; 0.1% triethylamine is added as a catalyst in the system; The hydroxypropyl chitosan, DMF / NMP mixed solvent was mixed at 3℃, and a sulfonating agent was added, and reacted at 32℃ for 90 min; 5% NaHCO3 solution was added to quench the residual chlorosulfonic acid, and then the pH was adjusted to 3, dialyzed, and vacuum dried to obtain sulfonated chitosan; the sulfonating agent is a mixture of chlorosulfonic acid and pyridine, and the molar ratio is 1:1; the mass ratio of hydroxypropyl chitosan to sulfonating agent is 10:1.9; the ratio of hydroxypropyl chitosan to formamide is 12 g / 100 mL; the volume ratio of DMF to NMP in the DMF / NMP mixed solvent is 1:1; Step 2, dissolve acrylic acid in dimethyl sulfoxide, add nano cerium oxide and 1,10-phenanthroline in sequence, heat to 55℃, and react for 1.5 h; vacuum filtration, washed with ethanol for 3 times, recrystallized with acetone / ether, and vacuum dried at 45℃ for 9 h to obtain triacrylic acid phenanthroline cerium hybrid CeO2; the mass ratio of nano cerium oxide, acrylic acid and 1,10-phenanthroline is 1:0.40:0.6; the amount of dimethyl sulfoxide is 15.5 times the mass of acrylic acid; the acrylic acid contains 0.05wt% polymerization inhibitor 4-methoxyphenol, and the reaction is carried out under nitrogen protection; Step 3, dissolve the sulfonated chitosan in a DMF / phosphate buffer mixed solution, dissolve heparin in a phosphate buffer, and mix them under light shielding conditions, and stir at a speed of 200 rpm for 30 min; add dopamine (hydrochloride) and stir for 10 min; add unsaturated monomers under nitrogen atmosphere protection and stir for 120 min; add a photoinitiator and stir for 30 min; add a DMF / phosphate buffer mixed solution to obtain a surface treatment agent with a concentration of 18wt%; then pass through a 0.45μm filter membrane, and adjust the pH to 7.0; the surface treatment agent comprises the following mass components: 6.5 parts of sulfonated chitosan, 4.5 parts of heparin, 2.5 parts of dopamine, 30 parts of unsaturated monomers, and 1.5 parts of a photoinitiator benzophenone; the unsaturated monomers comprise the following mass components: 9 parts of N-vinyl pyrrolidone, 5 parts of sodium p-styrene sulfonate, 1.5 parts of triacrylic acid phenanthroline cerium hybrid CeO2, and 2.7 parts of lauryl methacrylate; the volume ratio of DMF to phosphate buffer (PBS, pH 7.4) is 6:4; the two times of adding the DMF / phosphate buffer mixed solution are the same; Step 4, take the polyether sulfone nanofiber membrane as a support layer, immerse the surface treatment agent, and the immersion ratio of the polyether sulfone nanofiber membrane to the surface treatment agent is 1g:12mL; the immersion time is 8 min; the pressure of the extrusion roller is 0.2MPa; UV irradiation, the process conditions of UV irradiation are: under nitrogen atmosphere protection, wavelength 365nm, light intensity 9mW / cm², and irradiation time 8min; then wavelength 365nm, light intensity 18mW / cm 2 , and irradiation time 18min; a functional layer is formed to obtain a dialysis membrane.

[0038] Embodiment 3: A preparation method of an antibacterial nanofiber hemodialysis membrane, comprising the following processes: Step 1, dissolve citric acid in deionized water, add chitosan, heat to 62℃, react for 150 min; add water, adjust the pH of the system to neutral, precipitate with acetone, wash with ethanol, obtain citric acid-chitosan; the mass ratio of chitosan to citric acid is 1:1.3; the ratio of citric acid to deionized water is 15g / 100mL; Mix citric acid-chitosan and glycidol, react at 53℃ for 8h; cool to room temperature, add ice water to terminate the reaction; add acetone to precipitate, filter and wash; redissolve in acetic acid solution, dialysis, vacuum drying, obtain hydroxypropyl chitosan; the mass ratio of citric acid-chitosan to glycidol is 10:6; add 0.1% triethylamine as catalyst in the system; Mix hydroxypropyl chitosan and DMF / NMP mixed solvent at 3℃, add sulfonating reagent, react at 40℃ for 30 min; add 5% NaHCO3 solution to quench residual chlorosulfonic acid, then adjust the pH to 3, dialysis, vacuum drying, obtain sulfonated chitosan; the sulfonating reagent is a mixture of chlorosulfonic acid and pyridine, the molar ratio is 1:1; the mass ratio of hydroxypropyl chitosan to sulfonating reagent is 10:2.3; the ratio of hydroxypropyl chitosan to formamide is 15g / 100mL; the volume ratio of DMF to NMP in the DMF / NMP mixed solvent is 1:1; Step 2, dissolve acrylic acid in dimethyl sulfoxide, add nano cerium oxide and 1,10-phenanthroline in turn, heat to 60℃, react for 1h; reduce pressure and filter, wash with ethanol for 3 times, recrystallize with acetone / ether, vacuum dry at 50℃ for 6h, obtain triacrylic acid phenanthroline cerium hybrid CeO2; the mass ratio of nano cerium oxide, acrylic acid and 1,10-phenanthroline is 1:0.45:0.7; the amount of dimethyl sulfoxide is 16.7 times the mass of acrylic acid; acrylic acid contains 0.05wt% polymerization inhibitor 4-methoxyphenol, the reaction is carried out under nitrogen protection; Step 3, dissolve the sulfonated chitosan in the DMF / phosphate buffer mixture, dissolve the heparin in the phosphate buffer, mix the two under light protection, stir at a speed of 200 rpm for 30 min; add dopamine (hydrochloride) and stir for 10 min; under the protection of nitrogen atmosphere, add the unsaturated monomer and stir for 120 min; add the photoinitiator and stir for 30 min; add the DMF / phosphate buffer mixture to obtain a surface treatment agent with a concentration of 20 wt%; then pass through a 0.45 μm filter membrane to adjust the pH to 7.5; the surface treatment agent comprises the following mass components: 8 parts of sulfonated chitosan, 5 parts of heparin, 3 parts of dopamine, 40 parts of unsaturated monomer, and 2 parts of photoinitiator benzophenone; the unsaturated monomer comprises the following mass components: 10 parts of N-vinyl pyrrolidone, 6 parts of sodium p-styrene sulfonate, 2 parts of cerium triacrylate phenanthroline hybrid CeO2, and 3.0 parts of lauryl methacrylate; DMF / phosphate buffer (PBS, pH 7.4) = 6:4; the two additions of the DMF / phosphate buffer mixture are the same; Step 4, take the polyether sulfone nanofiber membrane as a support layer, immerse the surface treatment agent, and the immersion ratio of the polyether sulfone nanofiber membrane and the surface treatment agent is 1 g:15 mL; the immersion time is 10 min; the extrusion roller pressure is 0.3 MPa; UV irradiation, the process conditions of UV irradiation are: under the protection of nitrogen atmosphere, wavelength 365 nm, light intensity 10 mW / cm², irradiation time 10 min; then wavelength 365 nm, light intensity 20 mW / cm 2 , irradiation time 20 min; a functional layer is formed to obtain a dialysis membrane.

[0039] Comparative Example 1: A preparation method of an antibacterial nanofiber hemodialysis membrane, comprising the following processes: Step 1, mix chitosan and a DMF / NMP mixed solvent at a temperature of 3°C, add a sulfonating reagent, and react at 25°C for 180 min; add a 5% NaHCO3 solution to quench residual chlorosulfonic acid, then adjust the pH to 3, dialyze, and vacuum dry to obtain sulfonated chitosan; the sulfonating reagent is a mixture of chlorosulfonic acid and pyridine with a molar ratio of 1:1; the mass ratio of chitosan to sulfonating reagent is 10:1.5; the ratio of hydroxypropyl chitosan to formamide is 10 g / 100 mL; the volume ratio of DMF to NMP in the DMF / NMP mixed solvent is 1:1; Steps 2-4 are the same as in Example 1 to obtain a dialysis membrane; the surface treatment agent comprises the following mass components: 5 parts of sulfonated chitosan, 3 parts of heparin, 2 parts of dopamine, 20 parts of unsaturated monomer, and 1 part of photoinitiator benzophenone; the unsaturated monomer comprises the following mass components: 8 parts of N-vinyl pyrrolidone, 4 parts of sodium p-styrene sulfonate, 1 part of cerium triacrylate phenanthroline hybrid CeO2, and 2.4 parts of lauryl methacrylate.

[0040] Preparation method of an antibacterial nanofiber hemodialysis membrane, comprising the following processes: Steps 1-3 are the same as steps 2-4 in Example 1, and a dialysis membrane is obtained; the surface treatment agent comprises the following mass components: 5 parts of chitosan, 3 parts of heparin, 2 parts of dopamine, 20 parts of unsaturated monomer, and 1 part of photoinitiator benzophenone; the unsaturated monomer comprises the following mass components: 8 parts of N-vinyl pyrrolidone, 4 parts of sodium p-styrene sulfonate, 1 part of tripropylene acid phenanthroline cerium hybrid CeO2, and 2.4 parts of lauryl methacrylate.

[0041] Preparation method of an antibacterial nanofiber hemodialysis membrane, comprising the following processes: Step 1, dissolve acrylic acid in solvent 95v% ethanol, add lanthanum salt and 1,10-phenanthroline in turn, heat to 60°C, and react for 4h; vacuum filtration, washed with ethanol twice, recrystallized with acetone / ethyl ether, vacuum dried at 40°C for 12h, and lanthanum tripropylene acid phenanthroline is obtained; the mass ratio of lanthanum salt, acrylic acid, and 1,10-phenanthroline is 1:3:1; the lanthanum salt is added in the form of lanthanum nitrate solution, and the concentration is 3.0wt%; the solvent is 22 times the mass of acrylic acid; the acrylic acid contains 0.1wt% polymerization inhibitor hydroquinone, and the reaction is carried out under nitrogen protection; Step 2, dissolve chitosan in DMF / phosphate buffer mixture, dissolve heparin in phosphate buffer, mix them under light shielding conditions, and stir at a speed of 200rpm for 30min; add dopamine (hydrochloride) and stir for 10min; add unsaturated monomer under nitrogen atmosphere protection and stir for 120min; add photoinitiator and stir for 30min; add DMF / phosphate buffer mixture to obtain a surface treatment agent with a concentration of 15wt%; then pass through a 0.45μm filter membrane, and adjust the pH to 6.5; the surface treatment agent comprises the following mass components: 5 parts of chitosan, 3 parts of heparin, 2 parts of dopamine, 20 parts of unsaturated monomer, and 1 part of photoinitiator benzophenone; the unsaturated monomer comprises the following mass components: 8 parts of N-vinyl pyrrolidone, 4 parts of sodium p-styrene sulfonate, 1 part of tripropylene acid phenanthroline lanthanum, and 2.4 parts of lauryl methacrylate; DMF / phosphate buffer (PBS, pH7.4)=6:4; the two additions of DMF / phosphate buffer mixture are the same; Step 3 is the same as step 4 in Example 1, and a dialysis membrane is obtained.

[0042] Preparation method of an antibacterial nanofiber hemodialysis membrane, comprising the following processes: Step 1, dissolve chitosan in DMF / phosphate buffer mixture, dissolve heparin in phosphate buffer, mix them under light protection, stir at 200 rpm for 30 min; add dopamine (hydrochloride) and stir for 10 min; add unsaturated monomer under nitrogen atmosphere and stir for 120 min; add photoinitiator and stir for 30 min; add DMF / phosphate buffer mixture to obtain surface treatment agent with a concentration of 15 wt%; then pass through 0.45 μm filter membrane to adjust pH to 6.5; the surface treatment agent comprises the following mass components: 5 parts of chitosan, 3 parts of heparin, 2 parts of dopamine, 20 parts of unsaturated monomer, and 1 part of photoinitiator benzophenone; the unsaturated monomer comprises the following mass components: 8 parts of N-vinyl pyrrolidone, 4 parts of sodium p-styrene sulfonate, and 2.4 parts of lauryl methacrylate; DMF / phosphate buffer (PBS, pH 7.4) = 6:4; the two additions of DMF / phosphate buffer mixture are the same; Step 2 is the same as step 4 in Example 1 to obtain a dialysis membrane.

[0043] Experiment: take the dialysis membranes obtained in Examples 1-3 and Comparative Examples 1-4 to prepare samples, and detect the performance of the samples and record the detection results: Mechanical property test: take GB / T 1040.3 as the reference standard to detect the tensile strength of the sample at a rate of 10 mm / min; before the experiment, the sample is balanced at 25°C and 50% humidity for 24 h; Anticoagulant property test: take GB / T 16886.4 as the reference standard to detect the coagulation time (APTT) of the sample; Antibacterial property test: take GB / T 20944.3 (shaking method) as the reference standard to detect the inhibition rate of the sample on E. coil and S. aureus, and the bacterial solution concentration is OD600=0.1 (~10 8 CFU / mL); and sterile PBS is used to soak the membrane as a negative control to verify the non-inhibition false positive; Take ASTM E2180-07 as the reference standard to detect the biofilm coverage rate of the sample, and the bacterial species is P. aeruginosa; Albumin adsorption capacity test: dissolve bovine serum albumin (BSA) in phosphate buffer (PBS, 0.01M, pH=7.4) to prepare a BSA solution with a concentration of 1.0 mg / mL; place the sample in the BSA solution and incubate in a 37°C constant temperature shaker at a speed of 60-80 rpm for 2 h; detect the BSA concentration of the supernatant to calculate the albumin adsorption capacity (μg / cm 2 ); Water flux test: cut the effective area to 10 cm 2The circular membrane sample was placed in a dialysis cell and sealed. After 10 min of equilibration, the volume of the permeate was collected within 30 min, and the water flux (J) was calculated. In the experiment, the transmembrane pressure was 100 mmHg (13.3 kPa), the temperature was 37±0.5℃, and the test liquid was ultrapure water; β2-microglobulin (β2-MG) clearance test: The β2-microglobulin clearance of the sample was tested using a simulated dialysis system. The blood chamber contained PBS (pH 7.4) containing β2-MG (100 mg / L), and the dialysate chamber contained pure PBS (pH 7.4). The blood flow rate was 200 mL / min, and the dialysate flow rate was 500 mL / min. The experiment was performed at a temperature of 37℃ for 4 h. The β2-MG concentration was determined using an ELISA method, and the clearance rate was calculated. Long-term stability test: The performance decay rate (%) of the sample was detected after 100 times of simulated dialysis.

[0044] Table 1, mechanical properties, anticoagulant properties, and antibacterial performance test data

[0045] Table 2, adsorption, long-term stability test data

[0046] According to the data in the above table, the following conclusions can be clearly obtained: The dialysis membranes obtained in Examples 1-3 were compared with the dialysis membranes obtained in Comparative Examples 1-4, and the test results showed that, Compared with the comparative examples, the dialysis membranes obtained in Examples 1-3 had more excellent tensile strength, clotting time, and bacteriostatic effect. On this basis, the anti-protein adsorption, water flux, β2-MG clearance rate, and long-term stability were maintained well. This fully demonstrates that the present application improves the antibacterial performance of the dialysis membrane and simultaneously improves the mechanical properties, anticoagulation, permeability, low protein adsorption, and long-term stability.

[0047] Compared with Example 1, the preparation process of sulfonated chitosan in the surface treatment agent was different in Comparative Example 1; sulfonated chitosan was replaced by chitosan in Comparative Example 2; sulfonated chitosan in the surface treatment agent was replaced by chitosan, and cerium triacrylphenylphosphine oxide hybrid CeO2 in the unsaturated monomer was replaced by lanthanum triacrylphenylphosphine oxide in Comparative Example 3; sulfonated chitosan in the surface treatment agent was replaced by chitosan in Comparative Example 4, and no triacrylphenylphosphine oxide cerium hybrid CeO2 was added. The performance of the dialysis membranes obtained in Comparative Examples 1-4 deteriorated, and it can be seen that the present application sets the preparation process of the dialysis membrane and the components used, which can improve the comprehensive improvement of high-efficiency anticoagulant performance, high permeability, low protein adsorption, and long-term stability on the basis of imparting broad-spectrum antibacterial properties.

[0048] Comparative Example 2 is contrasted with Comparative Examples 3 and 4 to verify the influence of different acrylate-rare earth derivative Ce-TAP@CeO2 and La-TAP on the performance of hemodialysis membranes. The chitosan in Comparative Example 2 lacks sulfonated modification, resulting in a serious lack of hydrophilicity, anticoagulant property and anti-protein adsorption capacity, and the antibacterial property of chitosan itself is weak; thus, the performance of chitosan is significantly inferior to that of the examples, showing easy contamination, rapid flux and clearance decay, and poor antibacterial property. The La-TAP introduced in Comparative Example 3 provides certain antibacterial activity and a small amount of hydrophilic groups, but its effect is far inferior to that of Ce-TAP@CeO2.

[0049] As can be seen from the above, due to the synergistic enhancement of sulfonated chitosan and Ce-TAP@CeO2, the tensile strength, anticoagulant property, antibacterial property and solute clearance (β2-MG) of the dialysis membrane are significantly improved. Hydroxypropyl modification enhances the interfacial bonding force, which helps to improve the mechanical strength. The samples without sulfonation or CeO2 (Comparative Examples 1 / 4) have insufficient charge density, and the β2-MG adsorption is blocked, resulting in a decrease in solute transfer efficiency, a significant decrease in anticoagulant and antibacterial properties. The carboxymethyl chitosan (Comparative Example 3) has insufficient negative charge density, resulting in a decrease in β2-MG clearance rate. The introduction of the functional layer will cause a decrease in water flux, but the examples 1-3 have controllable decreases in water flux due to the hydrophilic modification of sulfonated chitosan and the ordered pore structure. The significant decrease in flux is caused by poor interfacial bonding or pore blockage (such as unsulfonated chitosan) in the comparative examples.

[0050] It is apparent for those skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and range of equivalents of the claims.

Claims

1. A method for preparing an antibacterial nanofibrous hemodialysis membrane, characterized by: The process comprises the following steps: Mixing chitosan derivative, heparin, dopamine, unsaturated monomer, initiator in DMF / phosphate buffer mixture to obtain a surface treatment agent; Taking nanofiber membrane as support layer, immersing the surface treatment agent, UV irradiation to form a functional layer, obtaining a dialysis membrane; The unsaturated monomer comprises the following mass components: 8-10 parts of N-vinyl pyrrolidone, 4-6 parts of sodium p-styrenesulfonate, 1-2 parts of triacrylphenanthroline cerium hybrid CeO2, 2.4-3.0 parts of lauryl methacrylate; The acrylic acid-rare earth derivative is triacrylphenanthroline cerium hybrid CeO2.

2. The method of claim 1, wherein the method is characterized by: The chitosan derivative is sulfonated chitosan, The sulfonated chitosan is prepared by the following process: Mixing hydroxypropyl chitosan and DMF / NMP mixed solvent at 0-5℃, adding sulfonating reagent, reacting at 25-40℃ for 30-180min to obtain sulfonated chitosan.

3. The method of claim 2, wherein the method is characterized by: The hydroxypropyl chitosan is prepared by the following process: Dissolving citric acid in deionized water, adding chitosan, heating to 58-62℃, reacting for 150-200min to obtain citric acid-chitosan; Mixing citric acid-chitosan and glycidol, reacting at 48-53℃ for 8-12h to obtain hydroxypropyl chitosan.

4. The method of claim 1, wherein the method is characterized by: The triacrylphenanthroline cerium hybrid CeO2 is prepared by the following process: Dissolving acrylic acid in dimethyl sulfoxide, adding nano cerium oxide and 1,10-phenanthroline in sequence, heating to 50-60℃, reacting for 1-2h to obtain triacrylphenanthroline cerium hybrid CeO2.

5. The method of claim 2, wherein the method is characterized by: The mass ratio of hydroxypropyl chitosan to sulfonating reagent is 10:(1.5-2.3).

6. The method for preparing an antibacterial nanofiber hemodialysis membrane according to claim 3, characterized in that: The mass ratio of chitosan to citric acid is 1:(1.2-1.3).

7. The method for preparing an antibacterial nanofiber hemodialysis membrane according to claim 3, characterized in that: The mass ratio of citric acid-chitosan to glycidol is 10:(4-6).

8. The method for preparing an antibacterial nanofiber hemodialysis membrane according to claim 1, wherein: The process conditions for UV irradiation are: wavelength 365 nm, light intensity 5-8 mW / cm 2 , irradiation 5-10 min; then wavelength 365 nm, light intensity 12-18 mW / cm 2 , irradiation 12-20 min.

9. The method for preparing an antibacterial nanofiber hemodialysis membrane according to claim 4, characterized in that: The mass ratio of nano cerium oxide to acrylic acid to 1,10-phenanthroline is 1:(0.35-0.45):(0.5-0.7).

10. An antibacterial nanofiber hemodialysis membrane prepared by the preparation method according to any one of claims 1-9.

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