A platelet-rich suspension leukocyte-removing filtration membrane and its preparation method

Abstract

This invention relates to a filter membrane and its preparation method, particularly to a platelet-rich suspension leukocyte-removing filter membrane and its preparation method. The method uses polyethersulfone (PES) material, which has stable mechanical properties, heat resistance, and chemical properties, as the core material, and polylactic acid (PLA) material, which has good biocompatibility and safety, as the outer material. A coaxial electrospinning process is employed to prepare the PES-PLA filter membrane. Furthermore, a vinylpyrrolidone-acrylamide copolymer is grafted onto the surface of the PES-PLA filter membrane. The resulting platelet-rich suspension leukocyte-removing filter membrane has a narrow pore size distribution, high porosity, and good hydrophilicity, biocompatibility, and antibacterial properties. It can effectively filter out leukocytes from platelet suspensions and reduce the risk of bacterial contamination.

Description

Technical Field

[0001] This invention relates to a filter membrane and its preparation method, and more particularly to a platelet-rich suspension leukocyte-removing filter membrane and its preparation method. Background Technology

[0002] Platelets play multiple crucial roles in the medical field, including hemostasis and coagulation, transfusion therapy for thrombocytopenic diseases, promoting wound healing and tissue repair, and the prevention and treatment of cardiovascular and cerebrovascular diseases. With the development of medical technology, the market demand for platelet-rich plasma (PRP) and leukocyte-reduced platelet products is continuously growing, indicating that platelet-related products have broad application prospects and market potential in the future healthcare industry. Consequently, the demand for easy-to-use platelet-rich leukocyte-reduced filters with high leukocyte removal rates is also continuously increasing.

[0003] Currently, common platelet collection methods include manual separation and apheresis platelet enrichment. Although these methods allow for targeted collection based on clinical needs, the overall quality of the resulting platelet preparations is not high due to variations in personnel skills and low leukocyte removal rates (generally only reaching the 1 log level). Other methods, such as apheresis platelets, washing, and gel filtration, all carry risks of platelet activation and involve complex procedures.

[0004] Common filters used for whole blood leukocyte removal typically employ polybutylene terephthalate (PBT) meltblown nonwoven fabric as the filter membrane material. This material offers advantages such as fine fibers, relatively small pore size, good biocompatibility, and low cost. However, when used for platelet enrichment, this material often suffers from problems such as easy platelet activation and low platelet yield. Existing platelet-rich suspension leukocyte filters using meltblown PBT membranes on the market suffer from a large average pore size and wide pore size distribution, making it difficult to achieve a leukocyte removal rate exceeding 99.5%.

[0005] Chinese patent CN110787647A discloses the preparation of a platelet-removing leukocyte-removing filter membrane. This patent uses acrylate-modified PBT meltblown nonwoven fabric with a grafting rate of 10-20% as the base fabric, impregnating it in a prepolymer solution of vinylpyrrolidone and vinyl acetate to obtain a filter membrane with a leukocyte removal rate of over 99.9%. However, the vinyl acetate used in this process has poor biocompatibility and is classified as a Group 2B carcinogen, posing certain safety risks to the resulting filter membrane.

[0006] Chinese patent CN104923091B discloses the preparation of a leukocyte filtration membrane with high leukocyte retention rate, high platelet permeability, and low hemolysis rate. This patent uses PBT meltblown nonwoven fabric as the base fabric, immerses the nonwoven fabric in a mixture containing grafting modifier, polymerization inhibitor, and initiator, and prepares a leukocyte filtration membrane with a grafting rate of 5-15% by γ-ray irradiation, obtaining a filter membrane with a pore size of 30-50 μm, a leukocyte filtration rate of 99.6%, and a platelet recovery rate of 89.7%. However, the preparation process uses γ-ray irradiation crosslinking, which requires relatively harsh production conditions in industrial applications, and the control of the grafting rate is relatively difficult. Summary of the Invention

[0007] In view of this, and to address the shortcomings of the prior art, the present invention provides a platelet-rich suspension leukocyte-removing filter membrane and its preparation method.

[0008] A platelet-rich suspension leukocyte-removing filtration membrane and its preparation method include the following steps:

[0009] S1: Preparation of polyethersulfone-polylactic acid (PLA) filter membrane: 15-30g of polyethersulfone is dissolved in 50-150g of organic solvent A to obtain a polyethersulfone solution. 10-20g of polylactic acid, 0.3-1g of nano-titanium dioxide, and 0.5-2g of hydrophilic modifier are added to 50-150g of organic solvent B and stirred to obtain a polylactic acid (PLA) solution. A coaxial electrospinning process is used to simultaneously spin the polyethersulfone solution and the PLA solution to prepare a polyethersulfone-PLA filter membrane with polyethersulfone as the core layer and PLA as the skin layer.

[0010] S2: Preparation of platelet-rich suspension leukocyte-reducing filtration membrane: Dissolve 5-10g of vinylpyrrolidone and 10-20g of acrylamide in 800-1000mL of deionized water to obtain a mixed solution. Completely immerse the polyethersulfone-polylactic acid (PESA) filter membrane in the mixed solution. Add an initiator dropwise to the mixed solution containing the PESA filter membrane. The amount of initiator is 3-6% of the total mass of vinylpyrrolidone and acrylamide. Seal the reaction. After the reaction is completed, filter, rinse and dry to obtain the platelet-rich suspension leukocyte-reducing filtration membrane.

[0011] Further, step S1, the preparation of the polyethersulfone-polylactic acid filter membrane, specifically includes the following steps:

[0012] S1.1: Place 15-30g of polyethersulfone into 50-150g of organic solvent A, and stir magnetically at 200-600rpm for 20-50min until the polyethersulfone is completely dissolved to obtain a polyethersulfone solution;

[0013] S1.2: Place 10-20g polylactic acid, 0.3-1g nano titanium dioxide and 0.5-2g hydrophilic modifier into 50-150g organic solvent B, and magnetically stir at 200-600rpm for 20-50min until the polylactic acid and hydrophilic modifier are completely dissolved to obtain a polylactic acid solution;

[0014] S1.3: Polylactic acid solution and polyethersulfone solution were injected into syringes No. 1 and No. 2, each with a capacity of 10 mL. Polyethersulfone solution was injected into syringe No. 1 and polylactic acid solution was injected into syringe No. 2. The PVDF plastic tube was connected to the coaxial spinneret. Syringes No. 1 and No. 2 were fixed to the injection pump. The spinning voltage was set to 10-30 KV, the receiving distance was 10-20 cm, and the feed speed was 0.5-1.5 mL / h. 304 stainless steel was used as the receiving substrate for collection to obtain a polyethersulfone-polylactic acid filter membrane with polyethersulfone as the core layer and polylactic acid as the skin layer.

[0015] Furthermore, organic solvent A is at least one of dimethylformamide, N,N-dimethylacetamide, dichloromethane, acetone, and N-methylpyrrolidone.

[0016] Furthermore, the organic solvent B is at least one of N,N-dimethylacetamide, dichloromethane, chloroform, acetone, and tetrahydrofuran.

[0017] Furthermore, the hydrophilic modifier is at least one of hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.

[0018] Furthermore, the particle size of nano-titanium dioxide is 20–60 nm.

[0019] Furthermore, step S2, the preparation of the platelet-rich suspension leukocyte-reduced filtration membrane, specifically includes the following steps:

[0020] S2.1: Add 5-10g of vinylpyrrolidone and 10-20g of acrylamide to a reactor containing 800-1000mL of deionized water, and mix thoroughly by magnetic stirring at 200-600rpm for 10-20min to obtain a mixed solution.

[0021] S2.2: Completely immerse the polyethersulfone-polylactic acid filter membrane in the mixed solution, and introduce nitrogen gas into the reactor for deoxygenation treatment for 20-30 minutes. Then, add the initiator dropwise into the reactor. The amount of initiator is 3-6% of the total mass of vinylpyrrolidone and acrylamide. Then, seal the reactor and place it in a constant temperature oil bath at 60-80°C for 0.5-2 hours.

[0022] S2.3: After the reaction is completed, the polyethersulfone-polylactic acid filter membrane is filtered out from the reactor and rinsed with deionized water 3 to 5 times. Then, the rinsed polyethersulfone-polylactic acid filter membrane is placed in an 80°C oven to dry, and platelet-rich suspension leukocyte-removing filter membrane is obtained.

[0023] Furthermore, the initiator is azobisisobutyronitrile, potassium persulfate, azobisisobutyramidazole hydrochloride, or azobisisobutyramidovalerate.

[0024] A platelet-rich suspension leukocyte-removing filtration membrane is prepared by the above-mentioned method for preparing a platelet-rich suspension leukocyte-removing filtration membrane.

[0025] Furthermore, the platelet-rich suspension leukocyte-removing filter membrane is stacked to 3-10 layers to prepare a PF-type leukocyte filter, which is used for the filtration of leukocytes in the platelet-rich suspension and the recovery of platelets.

[0026] The present invention has the following advantages:

[0027] 1. In this invention, polyethersulfone (PES) material with stable mechanical properties, heat resistance, and chemical properties is used as the core material, and polylactic acid (PLA) with good biocompatibility and safety is used as the sheath material. A PES-PLA filter membrane is prepared by coaxial electrospinning. The PES-PLA filter membrane is then used to prepare a platelet-rich suspension leukocyte removal filter membrane. The platelet-rich suspension leukocyte removal filter membrane has the characteristics of uniform pore size, narrow pore size distribution, and high porosity, which is beneficial to improving the filtration rate of leukocytes in platelet-rich suspension.

[0028] 2. In this invention, the addition of a hydrophilic modifier to the polylactic acid solution can effectively improve the hydrophilicity of the polyethersulfone-polylactic acid filter membrane, thereby increasing the platelet recovery rate and the leukocyte removal rate. The addition of nano-titanium dioxide to the polylactic acid solution can effectively improve the antibacterial properties of the polyethersulfone-polylactic acid filter membrane, reduce and prevent the risk of bacterial contamination, and thus enable the platelet-rich suspension leukocyte removal filter membrane to have good hydrophilic and antibacterial properties.

[0029] 3. In this invention, grafting vinylpyrrolidone-acrylamide copolymer onto the surface of the polyethersulfone-polylactic acid filter membrane is beneficial to further improve the hydrophilicity and biocompatibility. The resulting platelet-rich suspension leukocyte-removing filter membrane achieves a filtration rate of 99% for leukocytes in the platelet suspension and a platelet yield of over 95%. Attached Figure Description

[0030] Figure 1 The image shows a scanning electron microscope (SEM) image of the platelet-rich suspension leukocyte-reduced filter membrane prepared in Example 1. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] A method for preparing a platelet-rich suspension leukocyte-reducing filtration membrane specifically includes the following steps:

[0034] S1: Preparation of polyethersulfone-polylactic acid filter membrane

[0035] S1.1: Place 18g of polyethersulfone into 100g of dimethylformamide solvent and stir magnetically at 400rpm for 30min until the polyethersulfone is completely dissolved to obtain a polyethersulfone solution;

[0036] S1.2: 12.6g polylactic acid, 0.63g nano-titanium dioxide with a particle size of 30nm and 0.84g hydroxyethyl cellulose are placed in 100g dichloromethane solvent and magnetically stirred at 400rpm for 30min until polylactic acid and hydroxyethyl cellulose are completely dissolved to obtain polylactic acid solution.

[0037] S1.3: Take 10 mL of polylactic acid solution and 10 mL of polyethersulfone solution and inject them into syringes No. 1 and No. 2, each with a capacity of 10 mL. Inject polyethersulfone solution into syringe No. 1 and polylactic acid solution into syringe No. 2. Connect the PVDF plastic tube to the coaxial spinneret and fix syringes No. 1 and No. 2 to the injection pump. Set the spinning voltage to 20KV, the receiving distance to 12cm, and the feed speed to 1mL / h. Use 304 stainless steel as the receiving substrate for collection to obtain a polyethersulfone-polylactic acid filter membrane with polyethersulfone as the core layer and polylactic acid as the skin layer.

[0038] S2: Preparation of platelet-rich suspension leukocyte-depleted filtration membrane

[0039] S2.1: Add 7g of vinylpyrrolidone and 14g of acrylamide to a reactor containing 1000mL of deionized water, and mix thoroughly by magnetic stirring at 200rpm for 20min to obtain a mixed solution.

[0040] S2.2: The polyethersulfone-polylactic acid filter membrane obtained in step S1.3 is completely immersed in the mixed solution obtained in step S2.1. Nitrogen gas is introduced into the reactor for deoxygenation treatment for 30 minutes. Then, 0.84 g of potassium persulfate is added dropwise into the reactor. The reactor is then sealed and placed in a 65°C constant temperature oil bath for 1 hour.

[0041] S2.3: After the reaction is completed, the polyethersulfone-polylactic acid filter membrane is filtered out from the reactor and rinsed with deionized water 5 times. Then, the rinsed polyethersulfone-polylactic acid filter membrane is placed in an 80℃ oven to dry, and platelet-rich suspension leukocyte-removing filter membrane is obtained. Figure 1 Scanning electron microscope image of a leukocyte-free filter membrane for platelet-rich suspension.

[0042] Example 2

[0043] A method for preparing a platelet-rich suspension leukocyte-reducing filtration membrane specifically includes the following steps:

[0044] S1: Preparation of polyethersulfone-polylactic acid filter membrane

[0045] S1.1: Place 18g of polyethersulfone into 100g of organic solvent A, wherein organic solvent A is a mixture of N,N-dimethylacetamide and dichloromethane in a volume ratio of 8:2. Stir magnetically at 400rpm for 30min until the polyethersulfone is completely dissolved to obtain a polyethersulfone solution.

[0046] S1.2: 12.6g of polylactic acid, 0.63g of nano-titanium dioxide with a particle size of 30nm and 1.5g of hydroxypropyl cellulose were placed in 100g of organic solvent B, wherein organic solvent B was prepared by mixing N,N-dimethylacetamide and dichloromethane in a volume ratio of 1:9. The mixture was magnetically stirred at 400rpm for 30min until the polylactic acid and hydroxypropyl cellulose were completely dissolved to obtain a polylactic acid solution.

[0047] S1.3: Take 10 mL of polylactic acid solution and 10 mL of polyethersulfone solution and inject them into syringes No. 1 and No. 2, each with a capacity of 10 mL. Inject polyethersulfone solution into syringe No. 1 and polylactic acid solution into syringe No. 2. Connect the PVDF plastic tube to the coaxial spinneret and fix syringes No. 1 and No. 2 to the injection pump. Set the spinning voltage to 20 KV, the receiving distance to 12 cm, and the feed speed to 0.8 mL / h. Use 304 stainless steel as the receiving substrate for collection to obtain a polyethersulfone-polylactic acid filter membrane with polyethersulfone as the core layer and polylactic acid as the skin layer.

[0048] S2: Preparation of platelet-rich suspension leukocyte-depleted filtration membrane

[0049] S2.1: Add 6g of vinylpyrrolidone and 18g of acrylamide to a reactor containing 1000mL of deionized water, and mix thoroughly by magnetic stirring at 200rpm for 20min to obtain a mixed solution.

[0050] S2.2: The polyethersulfone-polylactic acid filter membrane obtained in step S1.3 is completely immersed in the mixed solution obtained in step S2.1. Nitrogen gas is introduced into the reactor for deoxygenation treatment for 30 minutes. Then, 0.96 g of azobisisobutyrazoline hydrochloride is added dropwise into the reactor. The reactor is then sealed and placed in a 65°C constant temperature oil bath for 1 hour.

[0051] S2.3: After the reaction is completed, the polyethersulfone-polylactic acid filter membrane is filtered out from the reactor and rinsed with deionized water 5 times. Then, the rinsed polyethersulfone-polylactic acid filter membrane is placed in an 80℃ oven to dry, and platelet-rich suspension leukocyte-removing filter membrane is obtained.

[0052] Example 3

[0053] A method for preparing a platelet-rich suspension leukocyte-reducing filtration membrane specifically includes the following steps:

[0054] S1: Preparation of polyethersulfone-polylactic acid filter membrane

[0055] S1.1: Place 24g of polyethersulfone into 100g of dimethylformamide solvent and stir magnetically at 400rpm for 30min until the polyethersulfone is completely dissolved to obtain a polyethersulfone solution;

[0056] S1.2: 20g of polylactic acid, 1g of nano-titanium dioxide with a particle size of 30nm and 2g of hydrophilic modifier are placed in 100g of dichloromethane solvent. The hydrophilic modifier is composed of hydroxypropyl cellulose and hydroxymethyl cellulose in a weight ratio of 1:1. The mixture is magnetically stirred at 400rpm for 30min until the polylactic acid and hydroxyethyl cellulose are completely dissolved to obtain a polylactic acid solution.

[0057] S1.3: Take 10 mL of polylactic acid solution and 10 mL of polyethersulfone solution and inject them into syringes No. 1 and No. 2, each with a capacity of 10 mL. Inject polyethersulfone solution into syringe No. 1 and polylactic acid solution into syringe No. 2. Connect the PVDF plastic tube to the coaxial spinneret and fix syringes No. 1 and No. 2 to the injection pump. Set the spinning voltage to 25 KV, the receiving distance to 15 cm, and the feed speed to 0.8 mL / h. Use 304 stainless steel as the receiving substrate for collection to obtain a polyethersulfone-polylactic acid filter membrane with polyethersulfone as the core layer and polylactic acid as the skin layer.

[0058] S2: Preparation of platelet-rich suspension leukocyte-depleted filtration membrane

[0059] S2.1: Add 6g of vinylpyrrolidone and 18g of acrylamide to a reactor containing 1000mL of deionized water, and mix thoroughly by magnetic stirring at 200rpm for 10min to obtain a mixed solution.

[0060] S2.2: The polyethersulfone-polylactic acid filter membrane obtained in step S1.3 is completely immersed in the mixed solution obtained in step S2.1. Nitrogen gas is introduced into the reactor for deoxygenation treatment for 30 minutes. Then, 0.96g of azodicyanovalerate is added dropwise into the reactor. The reactor is then sealed and placed in a 65°C constant temperature oil bath for 1 hour.

[0061] S2.3: After the reaction is completed, the polyethersulfone-polylactic acid filter membrane is filtered out from the reactor and rinsed with deionized water 5 times. Then, the rinsed polyethersulfone-polylactic acid filter membrane is placed in an 80℃ oven to dry, and platelet-rich suspension leukocyte-removing filter membrane is obtained.

[0062] Comparative Example 1

[0063] Compared with Example 1, Comparative Example 1 differs in that the coaxial electrospinning process in step S1.3 is replaced with the traditional single-nozzle electrospinning process. Specifically, 10 mL of polylactic acid solution and 10 mL of polyethersulfone solution are mixed to obtain a polylactic acid-polyethersulfone mixture. The polylactic acid-polyethersulfone mixture is injected into a syringe, and the syringe is fixed on an injection pump for electrospinning. The spinning voltage is 20 KV, the receiving distance is 12 cm, and the feed rate is 1 mL / h to form a polyethersulfone-polylactic acid mixed filter membrane. In addition, the polyethersulfone-polylactic acid filter membrane in step S2.2 is replaced with a polyethersulfone-polylactic acid mixed filter membrane. The polyethersulfone-polylactic acid mixed filter membrane is subjected to surface grafting treatment, while the other steps remain unchanged. A platelet-rich suspension leukocyte-removing filter membrane is prepared and is referred to as Comparative Example 1.

[0064] Comparative Example 2

[0065] Compared with Example 1, Comparative Example 2 differs in that the hydrophilic modifier used in step S1.2 is removed, while the other steps remain unchanged, and a platelet-rich suspension leukocyte-removing filter membrane is prepared, which is referred to as Comparative Example 2.

[0066] Comparative Example 3

[0067] Compared with Example 1, Comparative Example 3 differs in that step S2 is removed, while the other steps remain unchanged, to prepare a polyethersulfone-polylactic acid filter membrane, which is referred to as Comparative Example 3.

[0068] Comparative Example 4

[0069] Compared with Example 1, the difference of Comparative Example 4 is that the nano-titanium dioxide used in step S1.2 is removed, while the other steps remain unchanged, and a platelet-rich suspension leukocyte-removing filter membrane is prepared, which is referred to as Comparative Example 4.

[0070] Filter membrane physical performance test

[0071] The average pore size, average fiber diameter, porosity, and water contact angle of the platelet-rich suspension leukocyte-removing filter membranes prepared in Examples 1-3 and Comparative Example 1 were measured respectively. The results of the physical property measurements of the platelet-rich suspension leukocyte-removing filter membranes of each group are shown in Table 1.

[0072] Table 1:

[0073] Group Average pore size (μm) Average fiber diameter (nm) Porosity (%) Example 1 8.86 542 95 Example 2 9.51 533 93 Example 3 9.33 438 96 Comparative Example 1 11.82 762 87

[0074] As shown in Table 1, the platelet-rich suspension leukocyte removal filter membranes prepared in Examples 1-3 have a narrower average pore size distribution, an average fiber diameter that can be controlled below 600 nm, and a relatively higher porosity. This indicates that, compared with the traditional single-nozzle electrospinning process, the polyethersulfone-polylactic acid filter membrane prepared by the coaxial electrospinning process can control the fiber diameter below 600 nm, and the filter membrane has a narrow pore size distribution and high porosity, which is beneficial to improving the leukocyte removal rate.

[0075] Hydrophilicity test

[0076] The water contact angle of the platelet-rich suspension leukocyte-removing filter membranes prepared in Examples 1-3 and Comparative Example 2, as well as the polyethersulfone-polylactic acid filter membrane prepared in Comparative Example 3, was measured using a contact angle meter. The water contact angle measurement results of each group of platelet-rich suspension leukocyte-removing filter membranes are shown in Table 2.

[0077] Table 2:

[0078] Group Water contact angle (°) Example 1 55 Example 2 53 Example 3 58 Comparative Example 2 73 Comparative Example 3 65

[0079] As shown in Table 2, the platelet-rich suspension leukocyte-removing filtration membranes prepared in Examples 1-3 all had water contact angles of less than 60°, and their hydrophilicity was significantly better than that of Comparative Examples 2-3. This indicates that the addition of hydrophilic modifiers and the grafting modification of the polyethersulfone-polylactic acid filtration membrane surface by vinylpyrrolidone-acrylamide copolymer can effectively improve the hydrophilicity of the platelet-rich suspension leukocyte-removing filtration membrane.

[0080] Filtration performance test

[0081] The platelet-rich suspension leukocyte-removing filtration membranes prepared in Examples 1-3 and Comparative Examples 1-2, and the polyethersulfone-polylactic acid filtration membrane prepared in Comparative Example 3 were stacked to 5 layers to prepare a PF-type leukocyte filter. 200 mL of platelet-rich suspension was filtered in each filter, and the platelet suspension volume, platelet concentration, and leukocyte count were recorded before and after filtration. The platelet recovery rate and leukocyte filtration rate were calculated, and the results are shown in Table 3.

[0082]

[0083] Where P h P represents the post-filtration platelet concentration. q V represents the pre-filtration platelet concentration. h V is the volume of the platelet suspension after filtration. q This represents the volume of platelet suspension before filtration.

[0084]

[0085] Where L0 is the number of white blood cells in the pre-filtration platelet-rich suspension, and L1 is the number of white blood cells in the post-filtration platelet-rich suspension.

[0086] Table 3:

[0087] Group Platelet recovery rate (%) Leukocyte filtration rate (%) Example 1 95.90 99.81 Example 2 95.05 99.68 Example 3 95.73 99.02 Comparative Example 1 89.71 92.94 Comparative Example 2 80.74 91.13 Comparative Example 3 84.73 93.54

[0088] As shown in Table 3, after the platelet-rich suspension leukocyte removal filtration membranes prepared in Examples 1-3 were used to prepare PF-type leukocyte filters, the platelet recovery rate in the platelet-rich suspension reached 95% and the leukocyte removal rate reached 99%. This indicates that in the preparation process of the platelet-rich suspension leukocyte removal filtration membrane, the use of coaxial electrospinning technology, the addition of hydrophilic modifiers, and the grafting modification of the polyethersulfone-polylactic acid filter membrane surface by vinylpyrrolidone-acrylamide copolymer can effectively improve the platelet recovery rate and leukocyte removal rate in the platelet-rich suspension leukocyte removal filtration membrane.

[0089] Antibacterial performance test

[0090] With a concentration of 10 7 The CFU / mL Staphylococcus aureus solution was divided into five equal portions as bacterial culture samples, each containing 2 mL. The platelet-rich suspension leukocyte-depleted filter membranes prepared in Examples 1-3 and Comparative Example 4 were placed in four of these bacterial culture samples as experimental groups, while the remaining sample served as a control group. All five bacterial culture samples were incubated at 37°C for 24 h. Subsequently, each sample was diluted 10-fold with phosphate-buffered saline (pH 7.4). 0.2 mL of each diluted sample was then spread onto its respective nutrient agar medium (prepared by a 1:30 mass ratio of agar and deionized water) and incubated at 37°C for 24 h. The inhibition rate was calculated by bacterial colony counting, and the results are shown in Table 4.

[0091] The formula for calculating the antibacterial rate is:

[0092] Where C0 represents the number of bacterial colonies in the control group and C1 represents the number of bacterial colonies in the experimental group.

[0093] Table 4:

[0094] Group Staphylococcus aureus inhibition rate (%) Example 1 99.6 Example 2 99.8 Example 3 99.5 Comparative Example 4 24.2

[0095] As shown in Table 4, after the platelet-rich suspension leukocyte-reducing filtration membranes prepared in Examples 1-3 were in contact with the bacterial solution for 24 hours, their antibacterial rate against Staphylococcus aureus could reach over 99%, demonstrating a significant antibacterial effect. This indicates that the addition of nano-titanium dioxide can effectively improve the antibacterial performance of the platelet-rich suspension leukocyte-reducing filtration membrane, which is beneficial in reducing the risk of bacterial contamination.

[0096] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Parts not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A method for preparing a platelet-rich suspension leukocyte-reducing filtration membrane, characterized in that, Includes the following steps: S1: Preparation of polyethersulfone-polylactic acid (PLA) filter membrane: 15-30g of polyethersulfone is dissolved in 50-150g of organic solvent A to obtain a polyethersulfone solution. 10-20g of polylactic acid, 0.3-1g of nano-titanium dioxide, and 0.5-2g of hydrophilic modifier are added to 50-150g of organic solvent B and stirred to obtain a polylactic acid (PLA) solution. A coaxial electrospinning process is used to simultaneously spin the polyethersulfone solution and the PLA solution to prepare a polyethersulfone-PLA filter membrane with polyethersulfone as the core layer and PLA as the skin layer. S2: Preparation of platelet-rich suspension leukocyte-reducing filter membrane: 5-10g of vinylpyrrolidone and 10-20g of acrylamide are dissolved in 800-1000mL of deionized water to obtain a mixed solution. The polyethersulfone-polylactic acid filter membrane is completely immersed in the mixed solution. An initiator is added dropwise to the mixed solution containing the polyethersulfone-polylactic acid filter membrane. The amount of initiator is 3-6% of the total mass of vinylpyrrolidone and acrylamide. The reaction is sealed. After the reaction is completed, the membrane is filtered, rinsed and dried to obtain the platelet-rich suspension leukocyte-reducing filter membrane. Organic solvent A is at least one of dimethylformamide, N,N-dimethylacetamide, dichloromethane, acetone, and N-methylpyrrolidone; Organic solvent B is at least one of N,N-dimethylacetamide, dichloromethane, chloroform, acetone, and tetrahydrofuran; The hydrophilic modifier is at least one of hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.

2. The method for preparing a platelet-rich suspension leukocyte-reducing filtration membrane according to claim 1, characterized in that, Step S1, preparation of the polyethersulfone-polylactic acid filter membrane, specifically includes the following steps: S1.1: Place 15-30g of polyethersulfone into 50-150g of organic solvent A, and stir magnetically at 200-600rpm for 20-50min until the polyethersulfone is completely dissolved to obtain a polyethersulfone solution; S1.2: Place 10-20g polylactic acid, 0.3-1g nano titanium dioxide and 0.5-2g hydrophilic modifier into 50-150g organic solvent B, and magnetically stir at 200-600rpm for 20-50min until the polylactic acid and hydrophilic modifier are completely dissolved to obtain a polylactic acid solution; S1.3: Polylactic acid solution and polyethersulfone solution were injected into syringes No. 1 and No. 2, each with a capacity of 10 mL. Polyethersulfone solution was injected into syringe No. 1 and polylactic acid solution was injected into syringe No.

2. The PVDF plastic tube was connected to the coaxial spinneret. Syringes No. 1 and No. 2 were fixed to the injection pump. The spinning voltage was set to 10-30 KV, the receiving distance was 10-20 cm, and the feed speed was 0.5-1.5 mL / h. 304 stainless steel was used as the receiving substrate for collection to obtain a polyethersulfone-polylactic acid filter membrane with polyethersulfone as the core layer and polylactic acid as the skin layer.

3. The method for preparing a platelet-rich suspension leukocyte-reducing filtration membrane according to claim 2, characterized in that, The particle size of nano-titanium dioxide is 20–60 nm.

4. The method for preparing a platelet-rich suspension leukocyte-reducing filtration membrane according to claim 1, characterized in that, Step S2, preparation of the platelet-rich suspension leukocyte-free filtration membrane, specifically includes the following steps: S2.1: Add 5-10g of vinylpyrrolidone and 10-20g of acrylamide to a reactor containing 800-1000mL of deionized water, and mix thoroughly by magnetic stirring at 200-600rpm for 10-20min to obtain a mixed solution. S2.2: Completely immerse the polyethersulfone-polylactic acid filter membrane in the mixed solution, and introduce nitrogen gas into the reactor for deoxygenation treatment for 20-30 minutes. Then, add the initiator dropwise into the reactor. The amount of initiator is 3-6% of the total mass of vinylpyrrolidone and acrylamide. Then, seal the reactor and place it in a constant temperature oil bath at 60-80°C for 0.5-2 hours. S2.3: After the reaction is completed, the polyethersulfone-polylactic acid filter membrane is filtered out from the reactor and rinsed with deionized water 3 to 5 times. Then, the rinsed polyethersulfone-polylactic acid filter membrane is placed in an 80°C oven to dry, and platelet-rich suspension leukocyte-removing filter membrane is obtained.

5. The method for preparing a platelet-rich suspension leukocyte-reducing filtration membrane according to claim 4, characterized in that, The initiator is azobisisobutyronitrile, potassium persulfate, azobisisobutyramidoline hydrochloride, or azobisisobutyramidoyl valerate.

6. A platelet-rich suspension leukocyte-removing filtration membrane, characterized in that, It was prepared using the method described in any one of claims 1 to 5 for preparing a platelet-rich suspension leukocyte-reducing filtration membrane.

7. A PF-type leukocyte filter for leukocyte filtration and platelet recovery in platelet-rich suspensions, characterized in that, The platelet-rich suspension leukocyte-removing filter membrane described in claim 6 is stacked to 3-10 layers to prepare a PF-type leukocyte filter.

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