Hydrogel, filter material for removing leukocytes from pet blood, and preparation method thereof

Abstract

The present invention belongs to the technical field of leukocyte filtration of blood products, specifically relating to a hydrogel, a filter material for removing leukocytes from pet blood, and a preparation method thereof. The hydrogel of the present invention is obtained by crosslinking the following raw materials in parts by weight: 2 parts polyvinyl alcohol and 4.37-8.74 parts citric acid. The present invention also provides a filter material for removing leukocytes from pet blood, obtained by coating the hydrogel onto a non-woven fabric. The present invention can be used to filter leukocytes from whole blood products of cats or dogs, and has promising application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of leukocyte filtration of blood products, and in particular relates to a hydrogel, a filter material for removing leukocytes from pet blood, and a preparation method thereof. Background Art

[0002] Blood transfusion is a common medical procedure in clinical medicine. Its primary purpose is to help patients recover from illnesses, bleeding during surgery, or heavy bleeding from accidental injuries. With the advancement of medical technology, both domestic and international studies have shown that many transfusion-related adverse reactions (such as non-hemolytic febrile reactions, respiratory distress syndrome, and ineffective platelet transfusion) are caused by white blood cells in the transfused whole blood or blood components. These symptoms are primarily caused by the production of leukocyte antibodies through an allogeneic immune reaction between the donor's blood and the recipient's. Furthermore, white blood cells in the blood are the primary vector for viral transmission. Therefore, to reduce the adverse reactions and viral infections caused by transfusion therapy, the removal of white blood cells from therapeutic blood products has become a new trend in modern blood transfusion.

[0003] With the improvement of living standards, more and more families begin to raise pet cats and dogs. Sick cats and dogs also need blood transfusions, including whole blood, suspended red blood cells, concentrated platelets and other blood components. Like humans, many of the side effects of blood transfusion in cats and dogs (such as non-hemolytic fever reaction, respiratory distress, ineffective platelet transfusion, etc.) are caused by white blood cells in the transfused whole blood or blood components. These symptoms are mainly caused by the white blood cell antibodies generated by the allogeneic immune reaction between the white blood cells in the donor blood and the recipient cat. And the white blood cell content in dog blood ((5.5-19.5)×10 9 / L) is higher than that of humans ((4~10)×10 9 / L), it is necessary to remove white blood cells in the blood. At the same time, the platelets in the blood of cats and dogs ((200-900)×10 9 / L) is higher than that of humans ((100-300)×10 9 / L).

[0004] According to references, the prothrombin time of dogs is 3-5 seconds less than that of humans, suggesting that the coagulation system of dogs is more easily activated. Due to the physiological function of platelets, when a blood vessel ruptures, the fluid dynamics of the blood changes, and platelets can quickly adhere to the ruptured blood vessel, quickly activate and release their intracellular substances, quickly activate the coagulation system, form clots and reduce blood loss. In addition, the platelet content in cat and dog blood is higher than that in humans. The easy adhesion and activation of platelets can lead to coagulation and easy clogging of filters. Therefore, existing white blood cell filters for human blood are not suitable for cat and dog blood. Therefore, the blood compatibility requirements for white blood cell filters for cats and dogs are higher, and the existing filter materials need to further improve blood compatibility (reduce the impact on the coagulation system and platelets).

[0005] Leukocyte filtration belongs to deep filtration. Combining its characteristics and the principle of blood filtration, the filter material used for leukocyte filtration must first consider its fiber diameter, filter material pore size, specific surface area, internal space structure and hydrophilicity. Secondly, it needs to have the following characteristics

[0006] 1) The total porosity should be large and be able to effectively block white blood cells.

[0007] 2) It has good chemical stability, dimensional stability, high temperature resistance, corrosion resistance, fatigue resistance and good mechanical properties.

[0008] 3) Excellent filtration rate and quick start-up.

[0009] 4) Low cost, suitable for industrial production.

[0010] Currently, polyester fiber non-woven fabrics (polybutylene terephthalate (PBT) or polyethylene terephthalate (PET), polypropylene (PP)) are mainly used. In addition, there are also reports on the application of materials such as polyvinyl alcohol in leukocyte filtration (for example: CN109843347B Blood component selective adsorption filter material and blood filter).

[0011] However, existing blood filtration materials are all developed for human blood. There are no filters specifically designed for removing leukocytes from cat or dog blood, either domestically or internationally. These filters cannot achieve both high leukocyte removal rates and high hemocompatibility (reducing clogging) for cat or dog blood, failing to meet practical application requirements. Therefore, developing leukocyte-removal filter materials for cat and dog blood has high application value. Summary of the Invention

[0012] In response to the problems of the prior art, the present invention provides a hydrogel, a filter material for removing leukocytes from pet blood, and a preparation method thereof, with the aim of achieving leukocyte filtration in the whole blood of pets such as cats and dogs.

[0013] A hydrogel is obtained by cross-linking the following raw materials in parts by weight:

[0014] 1-5 parts of polyvinyl alcohol,

[0015] Citric acid 4.37-8.74 parts.

[0016] Preferably, it is obtained by cross-linking the following raw materials in parts by weight:

[0017] 2 parts of polyvinyl alcohol,

[0018] Citric acid 4.37-6.5 parts.

[0019] Preferably, the degree of polymerization of the polyvinyl alcohol is 17-24.

[0020] Preferably, the alcoholysis degree of the polyvinyl alcohol is 88-99%.

[0021] The present invention also provides a filter material for removing leukocytes from pet blood, which is obtained by coating the hydrogel on a non-woven fabric.

[0022] Preferably, the filter material is used to remove leukocytes from the blood of felines or canines.

[0023] The present invention also provides a method for preparing the filter material, comprising the following steps:

[0024] Step 1: polyvinyl alcohol is prepared into solution A, and citric acid is prepared into solution B;

[0025] Step 2, immersing the non-woven fabric in solution A, and then adding solution B to solution A for cross-linking;

[0026] Step 3, take out the non-woven fabric, wash it, and then soak it in a sodium citrate solution.

[0027] Preferably, in step 1, the concentration of solution A is 0.1-0.5 g / ml; the concentration of step B is 0.437-0.874 g / ml;

[0028] In step 2, the volume ratio of solution A to solution B is 5:1 to 1:1;

[0029] In step 3, the concentration of the sodium citrate solution is 0.05-0.5 mol / L.

[0030] Preferably, in step 2, the cross-linking condition is 40-80° C. for 1-5 hours.

[0031] The present invention also provides use of the filter material for filtering leukocytes in pet whole blood.

[0032] This invention provides a novel hydrogel that can be used to modify the surface of nonwoven fabrics, resulting in a filter material suitable for pet blood filtration that balances leukocyte filtration efficiency and coagulation prevention. This is the first leukocyte filter material proposed for cat or dog blood and holds great promise for future applications.

[0033] Obviously, based on the above contents of the present invention, according to common technical knowledge and customary means in this field, without departing from the above basic technical ideas of the present invention, other various forms of modifications, replacements or changes can be made.

[0034] The following further describes the above content of the present invention in detail through specific embodiments in the form of examples. However, this should not be construed as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above content of the present invention fall within the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is the cross-linking principle of PVA and citric acid. DETAILED DESCRIPTION

[0036] In the following examples and experimental examples, reagents and materials not otherwise specified are commercially available.

[0037] Example 1

[0038] The filter material provided in this embodiment was prepared according to the following method:

[0039] Weigh 2g of polyvinyl alcohol (PVA, the brand can be 1788, 1799, 2488, the first two numbers represent the degree of polymerization and the last two numbers represent the degree of alcoholysis; in this embodiment, 1788 is specifically selected), add 20ml of deionized water, heat to 90°C to completely dissolve the polyvinyl alcohol, and then cool to the reaction temperature (60°C). Immerse the non-woven fabric in the PVA solution and add citric acid solution (4.37g citric acid dissolved in 10ml deionized water). After reacting at 60°C for 2 hours, use distilled water to wash the non-woven fabric to remove uncrosslinked PVA and excess citric acid. Soak the non-woven fabric in 0.1mol / L sodium citrate solution for 1h. Finally, wash the non-woven fabric with distilled water and dry it at 60°C.

[0040] Example 2

[0041] The filter material provided in this embodiment was prepared according to the following method:

[0042] Weigh 2g of polyvinyl alcohol (PVA, the brand can be 1788, 1799, 2488, the first two numbers represent the degree of polymerization and the last two numbers represent the degree of alcoholysis; in this embodiment, 1788 is specifically selected), add 20ml of deionized water, heat to 90°C to completely dissolve the polyvinyl alcohol, and then cool to the reaction temperature (60°C). Immerse the non-woven fabric in the PVA solution and add citric acid solution (6.5g citric acid dissolved in 10ml deionized water). After reacting at 60°C for 2 hours, use distilled water to wash the non-woven fabric to remove uncross-linked PVA and excess citric acid. Soak the non-woven fabric in 0.1mol / L sodium citrate solution for 1h. Finally, wash the non-woven fabric with distilled water and dry it at 60°C.

[0043] Example 3

[0044] The filter material provided in this embodiment was prepared according to the following method:

[0045] Weigh 2g of polyvinyl alcohol (PVA, the brand can be 1788, 1799, 2488, the first two numbers represent the degree of polymerization and the last two numbers represent the degree of alcoholysis; in this embodiment, 1788 is specifically selected), add 20ml of deionized water, heat to 90°C to completely dissolve the polyvinyl alcohol, and then cool to the reaction temperature (60°C). I immersed the non-woven fabric in the PVA solution and added citric acid solution (8.74g citric acid dissolved in 10ml deionized water). After reacting at 60°C for 2 hours, the non-woven fabric was washed with distilled water to remove uncross-linked PVA and excess citric acid. The non-woven fabric was soaked in 0.1mol / L sodium citrate solution for 1h, and finally washed with distilled water and dried at 60°C.

[0046] The technical solution of the present invention is further illustrated by experiments below.

[0047] Experimental Example 1 Whole Blood Filtration Experiment

[0048] 1. Experimental samples

[0049] Filter material 1: unmodified non-woven fabric (Wuhu Aidi Purification Equipment Co., Ltd., PET non-woven fabric).

[0050] Filter material 2: Commercially available disposable human whole blood leukocyte removal filter.

[0051] Filter material 3: the filter material prepared in Example 1.

[0052] Filter material 4: the filter material prepared in Example 2.

[0053] Filter material 5: the filter material prepared in Example 3.

[0054] 2. Experimental Methods

[0055] Whole blood filtration experiment:

[0056] The four filter media were individually loaded into 60mm diameter leukocyte filter housings. The filters were then ultrasonically welded and connected to PVC tubing and blood bags. Each bag was filled with 200mL of canine whole blood. Under a net pressure differential of one meter, the blood flowed through the leukocyte filter, and the outflowing blood was collected in the blood bag.

[0057] Characterization methods:

[0058] 1) Surface tension measurement:

[0059] Prepare different concentrations of sodium chloride (1%-4.5%) and calcium chloride (3%-5%) solutions, and use a liquid automatic surface tension meter to test the surface tension of the solutions. Use a syringe to drop liquids of different concentrations on the surface of the sample, and measure the number of droplets that are fully spread within 10 minutes. Let it stand for 10 minutes, and observe between the 10th and 11th minutes. If at least 9 out of 10 drops are soaked within 10 minutes, it is ok.

[0060] If the medium is porous, the liquid with this surface tension is considered to have wetted the medium material; on the contrary, if 2 or more drops out of 10 drops do not wet or are not absorbed within 10 minutes, the liquid with this surface tension is considered to be unable to wet the medium. For example, pure water (whose surface tension is 72×10 -5 N / cm) droplets are placed on the surface of the material, and 9 drops are wetted within 10 minutes; while the surface tension is 75×10 -5 If 10 droplets of liquid with a density of N / cm are placed on the surface of a material and 3 drops are not wetted within 10 minutes, then the critical surface tension of the material is defined as 73.5×10 -5 N / cm.

[0061] 2) Calculation method of leukocyte removal rate

[0062] Platelet recovery rate (%) = (white blood cell concentration before filtration x volume before filtration - residual white blood cell concentration after filtration x volume after filtration) / (white blood cell concentration before filtration x volume before filtration) x 100

[0063] The white blood cell concentration before filtration was determined by a five-differential blood cell counter, the remaining white blood cell concentration after filtration was obtained by a cell counting plate, and the volume was obtained by weighing.

[0064] 3) Calculation method of red blood cell recovery rate

[0065] Platelet recovery rate (%) = (red blood cell concentration after filtration x volume after filtration) / (red blood cell concentration before filtration x volume before filtration) x 100

[0066] The concentration of red blood cells before and after filtration was determined by a five-differential blood cell counter, and the volume was obtained by weighing.

[0067] 4) Calculation method of hemolysis rate

[0068] The test solution of the leukocyte-removing filter device or filter material is prepared by using 0.9% sodium chloride injection as an extraction medium and directly contacting it with blood. The amount of hemoglobin released by red blood cells is measured to detect the in vitro hemolysis degree of the leukocyte-removing filter or filter material.

[0069] 5) Filtering time

[0070] The time required to filter 200 mL of whole blood.

[0071] 6) Calculation method of blood loss rate

[0072] Blood loss rate (%) = (blood weight before filtration - blood weight after filtration) / (blood weight before filtration) x 100

[0073] The platelet concentration before and after filtration was determined using a five-differential blood cell counter, and the volume was obtained by weighing.

[0074] 3. Experimental Results

[0075] The blood-related indicators of the dogs were tested before and after filtration. The results are shown in the following table (N=6):

[0076]

[0077] The blood-related indicators of cats were tested before and after filtration. The results are shown in the following table (N=6):

[0078]

[0079]

[0080] Schematic diagram of the hydrogel structure formed on the surface of non-woven fabric after cross-linking of PVA and sodium citrate Figure 1 As shown in the table above. It can be seen from the results in the above table that increasing the concentration of citric acid can significantly increase the cross-linking degree of the hydrogel and reduce the hydrophilicity of the non-woven fabric. Although the hydrophilicity of filter material 4 is lower than that of filter material 3, the citric acid-sodium citrate in the PVA hydrogel can avoid the activation of the coagulation system and increase the platelet passage rate, which helps to improve the blood filtration performance. The pore size of filter material 5 is reduced due to excessive cross-linking of PVA and citric acid, which is not conducive to the passage of blood. It can be seen that when the ratio of PVA and sodium citrate is appropriate, the filter material of the present invention has good blood filtration performance and can meet the filtration needs of cat and dog blood.

[0081] On the other hand, because cat and dog blood contains higher levels of platelets and coagulation factors than human blood, the compatibility of the filter material with the platelets and coagulation system can affect the filtration rate and quality of the filtered blood. The present invention improves the compatibility of the filter material with platelets, facilitating blood flow through the nonwoven fabric and reducing filter clogging. Consequently, the filter material of the present invention reduces filtration time and achieves a high platelet recovery rate.

[0082] As can be seen from the above embodiments and experimental examples, the present invention provides a leukocyte filtration filter material for pets such as cats and dogs. This filter material can be used to directly filter whole blood, achieving high leukocyte removal efficiency and platelet recovery rate, and has excellent application prospects.

Claims

1. A filter material for removing leukocytes from pet blood, characterized by: It is obtained by preparing hydrogel as a coating on non-woven fabric; The hydrogel is obtained by cross-linking the following raw materials in parts by weight: 2 parts of polyvinyl alcohol, 4.37-6.5 parts of citric acid; The preparation method of the hydrogel comprises the following steps: Step 1: polyvinyl alcohol is prepared into solution A, and citric acid is prepared into solution B; Step 2, immersing the non-woven fabric in solution A, and then adding solution B to solution A for cross-linking; Step 3, take out the non-woven fabric, wash it, and then soak it in a sodium citrate solution.

2. The filter material according to claim 1, characterized in that: The degree of polymerization of the polyvinyl alcohol is 17-24.

3. The filter material according to claim 1, characterized in that: The alcoholysis degree of the polyvinyl alcohol is 88-99%.

4. The filter material according to claim 1, characterized in that: The filter material is used for removing leukocytes from the blood of felines or canines.

5. The method for preparing the filter material according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: polyvinyl alcohol is prepared into solution A, and citric acid is prepared into solution B; Step 2, immersing the non-woven fabric in solution A, and then adding solution B to solution A for cross-linking; Step 3, take out the non-woven fabric, wash it, and then soak it in a sodium citrate solution.

6. The preparation method according to claim 5, characterized in that: In step 1, the concentration of solution A is 0.1-0.5 g / ml; the concentration of step B is 0.437-0.874 g / ml; In step 2, the volume ratio of solution A to solution B is 5:1 to 1:1; In step 3, the concentration of the sodium citrate solution is 0.05-0.5 mol / L.

7. The preparation method according to claim 6, characterized in that: In step 2, the cross-linking condition is 40-80° C. for 1-5 hours.

8. Use of the filter material according to any one of claims 1 to 4 for preparing a filter for filtering leukocytes in whole blood of pets.

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