Soft-shell leukocyte filter

Abstract

The invention discloses a soft-shell leukocyte filter which comprises a filter membrane, the filter membrane comprises a plurality of coarse filter layers and fine filter layers, and the periphery of the filter membrane is fixed through an inner ring; a plurality of heat sealing areas are arranged on the filter membrane in the inner ring, and the total area of the heat sealing areas accounts for 2.7-5.0% of the effective filtering area of the filter membrane. According to the filter disclosed by the invention, the heat sealing area is additionally arranged on the filter membrane, so that white blood cells in collected blood (original blood) can be effectively removed to reach the European Union standard, and the filtering stability can also be ensured.

Description

Technical Field

[0001] The present invention relates to a blood filter, and particularly to a soft-shell leukocyte filter. Background Art

[0002] Leukocytes (leukocyte, white blood cell, abbreviated as: WBC) play an important role in the body's defense against foreign pathogen invasions and maintaining human immune functions. However, when leukocytes are transfused from blood donors to recipients, the situation is quite different: leukocytes in the blood of blood donors carry a lot of virus information, and the inflammatory factors they release can cause transfusion reactions. The cytokines released after leukocyte decomposition will also shorten the lifespan of red blood cells, thus causing harm to the transfused person's body. Therefore, leukocytes in the blood need to be filtered out before transfusion to make transfusion safer.

[0003] Filtering to remove leukocytes from blood has the advantages of easy operation and low cost, and is widely used. Classified according to the filter housing, it can be divided into two types: soft shell and hard shell. The hard shell restricts the filter membrane, which helps to improve the filtering effect of the internal filter membrane (CN111465440A), but the hard shell is not resistant to high-speed centrifugation and forms cracks during centrifugation, damaging the bag body connected to it. The soft shell can avoid this problem (CN 102861365 B), but due to the loss of the hard shell constraint, the filtering effect of the soft-shell filter has decreased: to achieve a leukocyte removal rate of 99.99%, the leukocyte content in the original blood needs to be considered. If the leukocyte content in the original blood is on the high side, the proportion of reaching a leukocyte removal rate of 99.99% will decrease; or the number of filter membrane layers needs to be increased to ensure a proportion of 99.99% removal rate. How to eliminate the influence of the fluctuation of the leukocyte content in the original blood and ensure a proportion of 99.99% removal rate is a problem that needs to be solved. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to provide a soft-shell leukocyte filter that improves the qualification rate of the leukocyte removal rate of 99.99%.

[0005] Technical Solution: A soft-shell leukocyte filter described in the present invention includes a filter membrane. The filter membrane includes a plurality of coarse filter layers and fine filter layers, and the periphery of the filter membrane is fixed by an inner ring; a plurality of heat-sealing areas are provided on the filter membrane within the inner ring, and the proportion of the total area of the heat-sealing areas relative to the effective filtering area of the filter membrane is 2.7 - 5.0%.

[0006] Preferably, the proportion of the heat-sealing area relative to the effective filtering area of the filter membrane is 2.8 - 4.5%, and the heat-sealing areas are arranged in a rectangular array and / or a circular array on the filter membrane.

[0007] Preferably, the total number of layers of the coarse filtration layer and the fine filtration layer is 7 - 15, the number of layers of the coarse filtration layer is 1 - 3, and both the coarse filtration layer and the fine filtration layer are non-woven fabrics of polyethylene terephthalate. More preferably, the total number of layers of the coarse filtration layer and the fine filtration layer is 7 - 12, and the number of layers of the coarse filtration layer is 1 - 2.

[0008] Preferably, the maximum pore diameter of the coarse filtration layer is 50 - 70 μm, and the maximum pore diameter of the fine filtration layer is 13 - 18 μm.

[0009] Preferably, the thickness of the coarse filtration layer is 0.7 - 0.9 mm; the thickness of the fine filtration layer is 1.0 - 1.2 mm.

[0010] Preferably, in order to avoid puncturing the filter membrane during the high-frequency heat sealing process, the width of the heat-sealing inner ring, the diameter or width of the heat-sealing area is not less than 4 mm. In order to ensure the uniform distribution of the heat-sealing area, the number of heat-sealing areas is not less than 4.

[0011] Preferably, the heat-sealing area is a circle with a diameter of 4.5 - 5.5 mm, and the number of heat-sealing areas is 7 - 10.

[0012] Preferably, inner membranes and outer membranes are respectively provided on the opposite sides of the filter membrane. The inner membrane is annular and connected to the heat-sealing inner ring. The outer membrane is heat-sealingly connected to the inner membrane, and a pre-filter cavity and a post-filter cavity are respectively formed on the opposite sides of the filter membrane. The pre-filter cavity and the post-filter cavity are respectively connected with an inlet conduit and an outlet conduit.

[0013] Preferably, the outlet of the inlet conduit and the inlet of the outlet conduit are located between the inner membrane and the outer membrane.

[0014] Preferably, a support is provided at the inlet end of the outlet conduit.

[0015] Advantages: Compared with the prior art, the present invention has the following remarkable advantages: 1. Excluding the interference of fluctuations in the white blood cell content in the original blood and ensuring the qualification rate of the white blood cell filtration rate of 99.99%: Regardless of whether the white blood cell content in the original blood is on the high side, the filter of the present invention can effectively remove white blood cells in the collected blood (original blood). The proportion of the filtration rate of 99.99% can reach 90% or more, ensuring the filtration stability. The residual amount of white blood cells in the blood filtered by the present invention is less than 1×10 6 / unit, meeting the EU standard and ensuring the filtration effectiveness; 2. Easy to process: During the heat-sealing process of the filter membrane, adding an orderly arrangement and a specific number of heat-sealing areas on the surface of the filter membrane at the same time can improve the filtration efficiency and stability. The heat-sealing areas and the inner ring are formed simultaneously, which is easy to process; 3. Wide applicable area: Filters for all blood types, red blood cell types, and platelet types can all use the solution of the present invention to improve stability, and are not limited by the number of layers of the filter membrane. Description of the Drawings

[0016] Figure 1 Cross-sectional view of the soft-shell blood filter structure of the present invention;

[0017] Figure 2 Cross-sectional view of the filter membrane structure provided with heat-sealing zones and inner rings;

[0018] Figure 3 Back view structure cross-sectional view of the soft-shell filter with 9 heat-sealing zones;

[0019] Figure 4 Schematic diagram of the arrangement of the heat-sealing zones of the soft-shell blood filter;

[0020] Figure 5 Schematic diagram of the arrangement of the heat-sealing zones of the red blood cell type soft-shell blood filter.

[0021] Reference numerals: 1. Outer membrane; 2. Inlet catheter; 3. Inner membrane; 4. Filter membrane; 41. Heat-sealing zone; 5. Outlet catheter; 6. Pre-filter chamber; 7. Post-filter chamber; 8. Outer ring; 9. Inner ring. Detailed implementation manners

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0023] Example 1: Structure and preparation method of the soft-shell filter

[0024] As Figure 1 shown, it is a schematic diagram of the structure of the soft-shell blood filter of the present invention, which is similar to the structure disclosed in CN 102861365 A. The soft-shell blood filter of the present invention mainly consists of a filter membrane assembly and an outer membrane 1. The outer membrane 1 is located on the opposite sides of the filter membrane assembly ( Figure 1 the perspectives in are the left and right sides), and is heat-sealed and connected to the outside of the filter membrane assembly around, forming a pre-filter chamber 6 and a post-filter chamber 7 on the left and right sides of the filter membrane assembly respectively. The outer membrane 1 is a soft membrane, which can be made of PVC material.

[0025] The filter membrane assembly ( Figure 1The structure within the dashed-line frame is composed of a filter membrane 4 and an inner membrane 3. The filter membrane 4 is located between two inner membranes 3. The filter membrane 4 is formed by stacking a number of coarse filter layers and fine filter layers. The periphery of the coarse filter layer and the fine filter layer is heat-sealed by high frequency to form an inner ring 9, so as to fix the periphery of the stacked coarse filter layer and fine filter layer. Among them, the total number of layers of the coarse filter layer and the fine filter layer is 7 - 15, the number of layers of the coarse filter layer is 1 - 3, and the remaining are fine filter layers. The coarse filter layer and the fine filter layer are both non-woven fabrics of polyethylene terephthalate. The maximum pore size of the coarse filter layer is 50 - 70 μm, and the thickness is 0.7 - 0.9 mm; the maximum pore size of the fine filter layer is 13 - 18 μm, and the thickness is 1.0 - 1.2 mm. A number of heat-sealing areas 41 are provided on the filter membrane 4 within the area enclosed by the inner ring 9. The heat-sealing areas 41 are used to improve the selective filtration efficiency and filtration stability of the soft-shell filter for white blood cells. The heat-sealing areas 41 and the inner ring 9 adopt the same heat-sealing process, that is, they are formed by high-frequency heat-sealing method. As Figure 2 , compared with the filter membrane 4 without heat-sealing, the thickness on both sides of the heat-sealing area 41 decreases. The outer peripheral contour of the heat-sealing area 41 is not limited, it can be dot-shaped, or it can be one of oval or polygon. For the convenience of processing, the outer peripheral contour of the heat-sealing area 41 is preferably circular; the heat-sealing areas 41 are preferably evenly distributed on the filter membrane 4, which can be a rectangular array, or a circular array, or a combination of both. The width of the inner ring 9, the width or diameter of the heat-sealing area 41 is preferably not less than 4 mm to avoid high-frequency heat-sealing from piercing through the filter membrane 4.

[0026] The inner membrane 3 is annular, with an inner ring edge and an outer ring edge. The inner ring edge forms a through hole in the middle of the inner membrane 3. The outer perimeters of the inner membrane 3 and the outer membrane 1 are larger than that of the filter membrane 4. The membrane body of the inner membrane 3 near the inner ring edge is connected to the periphery of the filter membrane 4 through the inner ring 9, and the membrane body near the outer ring edge is connected to the periphery of the outer membrane 1 through the outer ring 8, so as to form a pre-filter cavity 6 and a post-filter cavity 7 for accommodating blood on the left and right sides of the filter membrane assembly respectively. The inner membrane 3 is also a soft membrane, which can be made of PVC material. The outer ring 8 is also made by high-frequency heat-sealing process. The pre-filter cavity 6 and the post-filter cavity 7 are respectively connected to an inlet catheter 2 and an outlet catheter 5, so that the pre-filter cavity 6 can be connected to a blood collection bag or a blood collection mechanism, and the post-filter cavity 7 can be connected to a blood collection bag or a blood collection mechanism. Before the outer ring 8 is formed, one end of the inlet catheter 2 and the outlet catheter 5 close to the filter membrane 4 is located between the inner membrane 3 and the outer membrane 1. After heat-sealing to form the outer ring 8, the inner membrane 3 forms a smooth diversion groove outside the outlet end of the inlet catheter 2 and the inlet end of the outlet catheter 5, reducing the blood residue in the filter. A support member (CN 205041863 U) is integrally formed at the inlet end of the outlet catheter 5 to ensure the volume and drainage smoothness of the post-filter cavity 7. The inlet catheter 2 and the outlet catheter 5 are arranged in parallel in opposite directions, so that when the filter is hung, siphon filtration of blood is formed.

[0027] In this embodiment, the preparation method of the soft-shell blood filter is as follows:

[0028] (1) Assemble the filter membrane assembly: Stack the inner membranes 3, filter membranes 4, and inner membranes 3 in sequence, and use high-frequency heat sealing to form an inner ring 9 between the filter membrane 4 and the inner membrane 3, and several heat-sealing areas 41 are formed on the filter membrane 4 inside the inner ring 9.

[0029] (2) Assemble the filter: Stack the outer membrane 1, outlet conduit 5, filter membrane assembly, inlet conduit 2, and outer membrane 1 in sequence. The inlet conduit 2 and the outlet conduit 5 are lined with stainless steel rods, and the outer periphery of the filter membrane assembly and the outer membrane 1 is heat-sealed to form a pre-filter chamber 6 and a post-filter chamber 7 between both sides of the filter membrane assembly and the outer membrane 1. The inner membrane 3 is wrapped around the outlet end of the inlet conduit 2 and the inlet end of the outlet conduit 5 to form a smooth diversion groove.

[0030] The outer contour of the soft-shell blood filter of the present invention is square, and it can also be other shapes such as rhombus. The outer contour shape and size are determined according to the type of blood to be filtered (red blood cells, platelets, etc.) and volume.

[0031] Example 2: Filtration efficiency test of the soft-shell blood filter for all blood types

[0032] The filter membrane 4 of the soft-shell blood filter for all blood types is composed of 2 layers of coarse filtration layers and 8 layers of fine filtration layers. The thickness of each coarse filtration layer is 0.82 ± 0.05 mm, and the maximum pore size is 60 ± 10 μm; the thickness of each fine filtration layer is 1.11 ± 0.06 mm, and the maximum pore size is 15.5 ± 1.5 μm. According to the preparation method of the soft-shell blood filter in Example 1, circular dots with a radius of 2.5 mm are formed on the surface of the filter membrane 4, and the heat-sealing areas of different samples are set as shown in Samples 1-10 and Sample 12 in Table 1.

[0033] According to the standard number YY 0329—2024, the method for measuring the leukocyte residue amount, and the methods for measuring the recovery rates of red blood cells and platelets, using 400 mL of freshly collected whole blood as a sample, conduct a filtration efficiency test, and the test results are shown in Table 1.

[0034] Table 1: Parameter settings and filtration effects of the filter membrane samples of the all-blood-type filter

[0035]

[0036] In the above Table 1, (1) represents the average value of n samples, n = 10, and (2) represents that the sample has 6 layers of fine filtration layers and 1 layer of coarse filtration layer.

[0037] When the proportion of the total area of the heat-sealed area 41 relative to the effective filtration area of the filter membrane 4 is about 2.6% (2.5 - 2.6), the selective filtration effect of the filter on white blood cells can be improved, with a filtration rate of 99.99%, meeting the EU standard. However, the test data fluctuates greatly, which is not conducive to the qualification rate. When the proportion of the total area of the heat-sealed area 41 relative to the effective filtration area of the filter membrane is 2.8% - 4.5%, not only can the filtration rate reach 99.99%, but the data fluctuation also becomes significantly smaller, indicating that the stability of the filtration effect can be ensured. Among the tested samples, the proportion of white blood cell removal rate reaching 99.99% is above 90%. Further increasing the proportion of the heat-sealed area 41, such as in sample 12, both the filtration rate and stability decrease. After the filtration test, the heat-sealed area 41 set on the filter membrane 4 of the filter is not stained by red blood cells and appears white, indicating that the heat-sealed area 41 has lost its filtration ability, the effective filtration area decreases, and the filtration rate and stability increase instead. It may be that increasing the heat-sealed area not only prevents the filter membrane 4 from deforming during filtration but also improves the local adsorption ability of the filter membrane 4, thereby promoting the increase of the filtration rate. When the area proportion of the heat-sealed area continues to increase, the white blood cell filtration efficiency drops to 99.9%, and it cannot be further improved. It may be due to insufficient effective filtration area, resulting in a decrease in the filtration rate.

[0038] On this basis, the proportion of white blood cell filtration rate of 99.99% (qualified rate) and filtration stability of the orderly and uniform distribution of the heat-sealed area 41 (sample 6) are higher than those of the random distribution (sample 7).

[0039] Take sample 9 and conduct parallel tests on multiple samples. The detailed data of some test results are shown in Table 2.

[0040] Table 2: Detailed data of parallel tests of sample 9

[0041]

[0042] In the original blood samples of samples 1 to 3, the white blood cell contents are inconsistent. After filtration, the white blood cell contents are all lower than 1×10^6 / unit, indicating that regardless of the white blood cell content in the original blood, the filter of the present invention has a stable filtration effect and can ensure a qualified rate of 99.99% for the filtration rate.

[0043] Example 3: Test on the number of filter membrane layers of the whole-blood-type soft-shell blood filter

[0044] The sample 11 in this example is similar to sample 9 in Example 2. Nine circular heat-sealed areas with a radius of 2.5 mm are evenly formed on the filter membrane 4. The difference is that the number of fine filter layers is reduced to 7 layers and the number of coarse filter layers is reduced to 1 layer. The test results are shown in Table 1. The data shows that by setting the heat-sealed areas, even if the fine filter layer / coarse filter layer is reduced, excellent and stable white blood cell removal rate can still be maintained. The experimental data shows that when the total number of fine filter layers and coarse filter layers is reduced to 7 - 12 layers and the number of coarse filter layers can be reduced to 1 - 3, the white blood cell removal efficiency does not decrease and the removal rate is 99.99%.

[0045] Example 4: Filtration Efficiency Test of Red Blood Cell Type Soft-shell Blood Filter

[0046] The red blood cell type soft-shell blood filter is similar in structure to the soft-shell filter in Example 1: the filter membrane is composed of 1 layer of coarse filter layer and 8 layers of fine filter layers. The thickness of each coarse filter layer is 0.82 ± 0.05 mm and the maximum pore size is 60 ± 10 μm; the thickness of each fine filter layer is 1.11 ± 0.06 mm and the maximum pore size is 19.5 + 5.5 μm. The appearance and dimensions are different. The red blood cell type soft-shell blood filter is prepared according to the preparation method of the soft-shell blood filter in Example 1, and 5 circular dots with a radius of 2.5 mm are formed on the surface of the filter membrane. The arrangement method of the heat-sealed areas refers to Figure 5 . The filtration efficiency test is carried out in the same way as in Example 1. The test results show that by changing the filter specifications, the filtration rate of the filter for white blood cells can still reach 99.99%, meeting the EU standards.

Claims

1. A soft shell leukocyte filter, characterized in that: The invention comprises a filter membrane (4), wherein the filter membrane comprises a plurality of coarse filter layers and a fine filter layer, and the filter membrane (4) is fixed around by an inner ring (9); a plurality of heat-sealed areas (41) are provided on the filter membrane (4) located within the inner ring (9), and the total area of ​​the heat-sealed areas (41) accounts for 2.7 to 5.0% of the effective filter area of ​​the filter membrane (4).

2. The soft shell leukocyte filter according to claim 1, characterized in that: The heat-sealed areas (41) account for 2.8-4.5% of the effective filtering area of ​​the filter membrane, and the heat-sealed areas (41) are arranged in a rectangular array and / or a circular array on the filter membrane.

3. The soft shell leukocyte filter according to claim 1, characterized in that: The total number of the coarse filter layer and the fine filter layer is 7 to 15, the number of the coarse filter layer is 1 to 3, and the coarse filter layer and the fine filter layer are both made of polyethylene terephthalate non-woven fabric.

4. The soft shell leukocyte filter according to claim 1, characterized in that: The maximum pore size of the coarse filter layer is 50-70 μm, and the maximum pore size of the fine filter layer is 13-18 μm.

5. The soft shell leukocyte filter according to claim 4, characterized in that: The thickness of the coarse filter layer is 0.7-0.9 mm, and the thickness of the fine filter layer is 1.0-1.2 mm.

6. The soft shell leukocyte filter according to claim 1, characterized in that: The ring width of the inner ring (9) and the diameter or width of the heat-sealing zone (41) are not less than 4 mm, and the number of the heat-sealing zones is not less than 4.

7. The soft shell leukocyte filter according to claim 1, characterized in that: The heat-sealing area (41) is circular with a diameter of 4.5 to 5.5 mm, and the number of the heat-sealing areas (41) is 7 to 10.

8. The soft shell leukocyte filter according to claim 1, characterized in that: An inner membrane (3) and an outer membrane (1) are respectively provided on opposite sides of the filter membrane (4); the inner membrane (3) is annular and connected to the inner ring (9); the outer membrane (1) and the inner membrane (3) are heat-sealed to form a pre-filter cavity (6) and a post-filter cavity (7) on opposite sides of the filter membrane (4); the pre-filter cavity (6) and the post-filter cavity (7) are respectively connected to an inlet conduit (2) and an outlet conduit (5).

9. The soft shell leukocyte filter according to claim 8, characterized in that: The outlet of the inlet conduit (2) and the inlet of the outlet conduit (5) are located between the inner membrane (3) and the outer membrane (1).

10. The soft shell leukocyte filter according to claim 8, characterized in that: The inlet of the outlet duct (5) is provided with a support member.

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