Filter for filtering white blood cells

Abstract

The invention provides a filter for filtering white blood cells, and relates to the technical field of whole blood filtration. The filter element of the filter is modified by using agarose, chitosan and polyethylene glycol, so that the flowability of red blood cells passing through filter holes of the filter element is improved. Meanwhile, the modified filter element of the filter is applied to a secondary filter and used as a small-aperture filter element, whole blood passes through the filter through fall, the white blood cell filtering effect is guaranteed, damage to erythrocyte tissue in the filtering process is reduced, and the quality of the whole blood is improved. Experimental results show that when the filter for filtering out the white blood cells is used for filtering whole blood, the content of residual white blood cells per unit after filtration is as low as 105 orders of magnitude, and the FHb increase proportion after filtration is as low as 66%.

Description

Technical Field

[0001] The present invention relates to the technical field of whole blood filtration, and particularly relates to a filter for removing white blood cells. Background Art

[0002] Whole blood is a mixture formed by collecting blood in the human body into a blood collection bag, including red blood cells, white blood cells, platelets and plasma. White blood cells play a fundamental role in the body's immune system, but if blood components containing white blood cells are transfused to patients, many side effects will occur. Therefore, it is necessary to remove white blood cells from whole blood to obtain safe and high-quality whole blood. Currently, methods for removing white blood cells from whole blood include washing method, filtration method, etc. Among them, the filtration method is simple in operation and good in filtration effect, and is currently the widely used method for removing white blood cells. The filtration method utilizes the principles of mechanical blockage and adsorption to intercept white blood cells. Whole blood passes through the filter under its own gravity, and white blood cells are retained in the filter, while red blood cells with smooth surfaces and strong deformability can pass through the filter.

[0003] During the process of removing white blood cells, although red blood cells can pass through the pores by deforming, due to the mechanical friction with the filter material fibers, they will inevitably be damaged, thus affecting the quality of whole blood components. Therefore, it is of great significance to explore how to ensure the white blood cell filtration rate and reduce the damage to red blood cells during whole blood filtration. Summary of the Invention

[0004] In view of this, the present invention provides a filter for removing white blood cells, which can protect red blood cells on the basis of ensuring the white blood cell filtration rate, reduce the damage to red blood cells caused by mechanical friction during filtration, and improve the safety and quality of whole blood.

[0005] The filter for removing white blood cells provided by the present invention includes:

[0006] A liquid inlet pipe for conveying whole blood;

[0007] A large-aperture filtration chamber with an inlet connected to the outlet of the liquid inlet pipe;

[0008] A small-aperture filtration chamber with an inlet connected to the outlet of the large-aperture filtration chamber;

[0009] A liquid outlet pipe with an inlet connected to the outlet of the small-aperture filtration chamber;

[0010] Wherein, a first filter element is arranged in the large-aperture filtration chamber; a second filter element is arranged in the small-aperture filtration chamber;

[0011] The second filter element includes a second filter element body and a surface modification layer formed on the surface of the second filter element body; the surface modification layer is composed of agarose, chitosan and polyethylene glycol.

[0012] In some specific implementation manners, the mass ratio of the agarose, chitosan and polyethylene glycol is (15 - 20) : (10 - 20) : (5 - 15).

[0013] In some specific implementation manners, the mass ratio of the surface modification layer to the second filter core body in the second filter core is (5 - 20) : (80 - 95).

[0014] In some specific implementation manners, the molecular weight of the polyethylene glycol is 200 - 400.

[0015] In some specific implementation manners, the small-aperture filter cavity includes a second filter cavity and a third filter cavity, and the connection manner of the second filter cavity and the third filter cavity is in parallel.

[0016] In some specific implementation manners, the first filter core includes multiple layers of first non-woven fabrics; the average pore diameter of the first non-woven fabrics is 10 - 15 μm;

[0017] The second filter core body includes multiple layers of second non-woven fabrics, and the average pore diameter of the second non-woven fabrics is 3 - 6 μm.

[0018] In some specific implementation manners, the number of layers of the multiple layers of first non-woven fabrics and the multiple layers of second non-woven fabrics are independently selected from 5 - 30 layers.

[0019] In some specific implementation manners, the materials of the first non-woven fabric and the second non-woven fabric are independently selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polyurethane, polymethacrylate, polyacrylate, polyacrylonitrile, polyvinyl acetal, polyester, polyamide, polysulfone, polystyrene, polyethylene, polypropylene, cellulose and cellulose acetate.

[0020] In some specific implementation manners, the fiber diameters of the first non-woven fabric and the second non-woven fabric are independently selected from 0.3 - 3.0 μm.

[0021] In some specific implementation manners, the liquid outlet of the large-aperture filter cavity further includes a liquid homogenizing component, and the liquid homogenizing component is connected to the liquid inlet of the small-aperture filter cavity.

[0022] The present invention provides a filter for removing white blood cells. The filter provided by the present invention combines a large-aperture filtration chamber with a small-aperture filtration chamber, and at the same time, the filter material of the small-aperture filtration chamber is surface-modified with agarose, chitosan and polyethylene glycol, which improves the fluidity of red blood cells when passing through the filter pores of the filter element, reduces the damage to red blood cell tissue during the filtration process while ensuring the white blood cell filtration effect, and improves the quality of whole blood. Experimental results show that when filtering whole blood using the filter and method for removing white blood cells provided by the present invention, the residual white blood cell content per unit after filtration is as low as 10 5 order of magnitude, and the increase ratio of FHb after filtration is as low as 66%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the filter for removing white blood cells provided by the present invention;

[0024] Figure 2 Cross-sectional view of the filtration chamber in the filter for removing white blood cells provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] It should be understood that the expression "one or more of..." individually includes each of the objects recited after the said expression and various different combinations of two or more of the recited objects, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited objects should be understood to have the same meaning, unless otherwise understood from the context.

[0026] The terms "comprising", "having" or "containing", including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unrecited elements or steps, unless specifically stated otherwise or understood from the context.

[0027] It should be understood that as long as the present invention is still operable, the order of steps or the order of performing certain actions is not important. In addition, two or more steps or actions can be performed simultaneously.

[0028] The use of any and all examples or exemplary language such as "for example" or "including" herein is merely intended to better illustrate the present invention and does not limit the scope of the present invention unless a claim is made. No language in this specification should be construed as indicating that any unclaimed element is essential for the practice of the present invention.

[0029] In addition, the numerical ranges and parameters used to define the present invention are approximate values. Here, the relevant values in the specific embodiments have been presented as precisely as possible. However, any numerical value inevitably contains standard deviations caused by individual testing methods. Therefore, unless otherwise clearly stated, it should be understood that all ranges, quantities, numerical values, and percentages used in this disclosure are modified by "about". Here, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific numerical value or range.

[0030] The present invention provides a filter for filtering white blood cells, comprising:

[0031] A liquid inlet tube for transporting whole blood;

[0032] A large-aperture filtration chamber with an inlet connected to the outlet of the liquid inlet tube;

[0033] A small-aperture filtration chamber with an inlet connected to the outlet of the large-aperture filtration chamber;

[0034] A liquid outlet tube with an inlet connected to the outlet of the small-aperture filtration chamber;

[0035] Wherein, a first filter element is arranged in the large-aperture filtration chamber; a second filter element is arranged in the small-aperture filtration chamber;

[0036] The second filter element comprises a second filter element body and a surface modification layer formed on the surface of the second filter element body; the surface modification layer is composed of agarose, chitosan, and polyethylene glycol.

[0037] The inventors of the present invention have found that during the filtration of whole blood, the main reason for red blood cell damage is that when red blood cells pass through a filter element with a small aperture, they are deformed greatly and thus easily damaged, while when passing through a filter element with a large aperture, the damage is not obvious due to the small degree of deformation. Therefore, the present invention modifies the surface of the filter element with a small aperture in the filter, thereby reducing the damage to red blood cells during filtration and improving the quality of whole blood.

[0038] See Figure 1 , Figure 1 is a schematic structural diagram of the filter for filtering white blood cells provided by the present invention, comprising a liquid inlet tube 201; a large-aperture filtration chamber 202; a liquid homogenizing device 203; a first small-aperture filtration chamber 204; a second small-aperture filtration chamber 205, and a liquid outlet tube 206.

[0039] In order to filter out white blood cells and other impurities as fully as possible, the filter provided by the present invention adopts a two-stage filtration form, that is, the large-aperture filtration chamber and the small-aperture filtration chamber are used in combination to further improve the purity of whole blood.

[0040] The leukocyte-filtering filter provided by the present invention includes a liquid inlet pipe 201 for conveying whole blood, and the liquid outlet of the liquid inlet pipe 201 is connected to the liquid inlet of a large-aperture filtering cavity 202.

[0041] The large-aperture filtering cavity 202 is used for preliminarily intercepting leukocytes in whole blood, and at the same time removing some impurities and debris in the whole blood to prepare for the second filtration. The liquid outlet of the large-aperture filtering cavity 202 is respectively connected to a first small-aperture filtering cavity 204 and a second small-aperture filtering cavity 205.

[0042] A first filter element is arranged in the large-aperture filtering cavity 202. As a filter element for filtering whole blood, non-woven fabric has the advantages of high filtration efficiency, good air permeability, stable filtration performance, easy processing and shaping, and relatively low cost. Therefore, in some specific implementation manners of the present invention, non-woven fabric is selected as the material of the first filter element. To improve the filtration effect, in some specific implementation manners, the first filter element is preferably a multi-layer first non-woven fabric. In some specific implementation manners, the number of layers of the multi-layer first non-woven fabric is 5 to 30 layers, preferably 10 to 25 layers, and more preferably 12 to 23 layers. When non-woven fabric is used as a filter element for filtering leukocytes, if the fiber diameter is greater than 3.0 μm, the aperture of the made non-woven fabric is too large, and leukocytes cannot be effectively filtered; if the fiber diameter is less than 0.3 μm, the aperture of the made non-woven fabric is too small, which will damage red blood cells and cause blockage. Therefore, in some specific implementation manners, the fiber diameter of the first non-woven fabric is 0.3 to 3.0 μm, preferably 0.4 to 2.5 μm, and more preferably 0.5 to 2.0 μm. In some specific implementation manners, the equivalent aperture of the first non-woven fabric is 10 to 15 μm, preferably 10 to 14 μm. In some specific implementation manners, the material of the first non-woven fabric is selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polyurethane, polymethacrylate, polyacrylate, polyacrylonitrile, polyvinyl acetal, polyester, polyamide, polysulfone, polystyrene, polyethylene, polypropylene, cellulose, and cellulose acetate, preferably polyester, polyamide, polyacrylonitrile, or polypropylene, and more preferably polyethylene terephthalate, polybutylene terephthalate, or polyacrylonitrile.

[0043] To make the whole blood be filtered more fully, the large-aperture filtering cavity 202 of the present invention adopts Figure 2 the shown filtering cavity style, including a filtering cavity liquid inlet pipe 201, a liquid inlet cavity 202a, a filter element 202b, a liquid outlet cavity 202c, and a liquid outlet pipe 203. Among them, the liquid inlet cavity 202a and the liquid outlet cavity 202c are completely separated by the filter element 202b, so that the whole blood is fully filtered, and at the same time, the maximum effective area for filtering the whole blood is ensured, and the filtration efficiency is improved. The first small-aperture filtering cavity and the second small-aperture filtering cavity adopt the Figure 2 same structure, and the difference lies in the different non-woven fabrics.

[0044] The liquid homogenizing device 203 can evenly introduce the whole blood filtered by the large-aperture filtration chamber 202 into the first small-aperture filtration chamber 204 and the second small-aperture filtration chamber 205, ensuring a stable filtration speed and preventing the uneven inflow of whole blood, which may cause the filter to become blocked. The liquid inlet of the liquid homogenizing device 203 is connected to the liquid outlet of the large-aperture filtration chamber 202, and the liquid outlet is connected to the liquid inlets of the first small-aperture filtration chamber 204 and the second small-aperture filtration chamber 205. In some specific implementation manners, the liquid homogenizing device includes a plurality of vertically and parallelly arranged liquid homogenizing pipes.

[0045] Since the aperture of the small-aperture filtration chamber is small, in order to ensure the filtration speed and reduce the blockage of the filter, in some specific implementation manners of the invention, the first small-aperture filtration chamber 204 and the second small-aperture filtration chamber 205 are connected in parallel and jointly serve as the small-aperture filtration chamber of the filter of the present invention.

[0046] Second filter cores are provided in both the first small-aperture filtration chamber 204 and the second small-aperture filtration chamber 205. To reduce friction and increase the fluidity of red blood cells when passing through the filter core, the second filter core of the present invention includes a second filter core body and a surface modification layer formed on the surface of the second filter core body. Based on the advantages of the above non-woven fabric as the filter material for whole blood filtration, the present invention still selects the non-woven fabric as the material of the second filter core body in the first small-aperture filtration chamber 204 and the second small-aperture filtration chamber 205. In some specific implementation manners, the second filter core body is preferably a multi-layer second non-woven fabric. In some specific implementation manners, the number of layers of the multi-layer second non-woven fabric is 5 - 30 layers, preferably 10 - 25 layers, and more preferably 12 - 23 layers. In some specific implementation manners, the fiber diameter of the second non-woven fabric is 0.3 - 3.0 μm, preferably 0.4 - 2.5 μm, and more preferably 0.5 - 2.0 μm. In some specific implementation manners, the equivalent aperture of the second non-woven fabric is 3 - 6 μm, preferably 3 - 5 μm. In some specific implementation manners, the material of the second non-woven fabric is selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polyurethane, polymethacrylate, polyacrylate, polyacrylonitrile, polyvinyl acetal, polyester, polyamide, polysulfone, polystyrene, polyethylene, polypropylene, cellulose, and cellulose acetate, preferably polyester, polyamide, polyacrylonitrile, or polypropylene, and more preferably polyethylene terephthalate, polybutylene terephthalate, or polyacrylonitrile.

[0047] Agarose and chitosan can enhance the modification effect, and polyethylene glycol can reduce the friction force on the surface of the filter material fibers. Therefore, in the present invention, agarose, chitosan, and polyethylene glycol are used to perform surface modification on the second filter core body, so that a surface modification layer is formed on its surface. The surface modification layer has a small friction force, which can increase the fluidity of red blood cells when passing through the non-woven fabric fibers, so as to reduce the damage to the red blood cell tissue when filtering white blood cells. In some specific implementation manners, the mass ratio of agarose, chitosan, and polyethylene glycol is (15-20):(10-20):(5-15), preferably (15-20):(12-20):(5-15), and more preferably (15-20):(14-20):(6-15). In some specific implementation manners, the polyethylene glycol is preferably polyethylene glycol with a molecular weight of 200-400, such as PEG200, PEG300, or PEG400, and more preferably PEG200. In some specific implementation manners, the mass ratio of the surface modification layer to the second filter core body is (5-20):(80-95), preferably (10-20):(80-95), and more preferably (10-20):(80-90).

[0048] Based on the above advantages, the present invention also selects Figure 2 the shown filter cavity as the specific style of the first small-aperture filter cavity 204 and the second small-aperture filter cavity 205. The specific composition is as described above, and the present invention will not elaborate here.

[0049] The whole blood is filtered by the large-aperture filter cavity 202, the first small-aperture filter cavity 204, and the second small-aperture filter cavity 205 and then output by the liquid outlet pipe 206. The liquid inlet of the liquid outlet pipe 206 is connected to the liquid outlets of the first small-aperture filter cavity 204 and the second small-aperture filter cavity 205.

[0050] In some specific implementation manners of the present invention, the filtration speed of the whole blood passing through the filter is controlled at 90-120 drops per minute, preferably 95-115 drops per minute, and more preferably 100-115 drops per minute. Because if the filtration speed is too fast, the whole blood cannot fully infiltrate the filter disc when passing through the filter element, and the effective filtration area of the filter disc is reduced, which will cause the "flower disc" phenomenon and cause excessive damage to red blood cells; if the speed is too slow, it will cause blockage and affect the filtration efficiency.

[0051] In summary, the present invention provides a filter for removing white blood cells. The present invention first selects the combined use of a large-aperture filter chamber and a small-aperture filter chamber as the filter, and at the same time, the filter material of the small-aperture filter chamber is surface-modified with agarose, chitosan, and polyethylene glycol, improving the fluidity of red blood cells when passing through the filter pores of the filter element. While ensuring the white blood cell filtration effect, it reduces the damage to red blood cell tissue during the filtration process and improves the quality of whole blood. The experimental results show that using the filter and method for removing white blood cells provided by the present invention to filter whole blood, the residual white blood cell content per unit after filtration is as low as 10 5 orders of magnitude, and the increase ratio of FHb after filtration is as low as 66%.

[0052] The following further elaborates the present invention in conjunction with embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0053] Example 1

[0054] Select 15 layers of polyethylene terephthalate non-woven fabric as the first filter element, with a surface density of 42 g / m 2 , a thickness of 0.25 mm, a fiber diameter of about 2.0 μm, and an equivalent pore diameter of 10 μm (tested with a 3H-2000PB non-woven fabric pore size tester from Beijing Beishide Instrument Research Institute);

[0055] Select polyethylene terephthalate non-woven fabric as the second non-woven fabric, with a surface density of 40 g / m 2 , a thickness of 0.22 mm, a fiber diameter of about 1.5 μm, and an equivalent pore diameter of 7 μm; Prepare a modified preparation by mixing agarose, chitosan, and polyethylene glycol PEG200 in a ratio of 15:10:8, and spray it on the above-mentioned second non-woven fabric for modification according to the mass ratio of the modified preparation to the non-woven fabric of 10:90, and then dry it at 150 °C for 5 h. Take 15 layers of the modified second non-woven fabric as the second filter element.

[0056] Select medical soft PVC as the filter chamber material, and use high-frequency heat-sealing and melting to form the Figure 2 shown filter chamber, including a filter chamber inlet pipe 201, an inlet chamber 202a, a filter element 202b, an outlet chamber 202, and an outlet pipe 203. First, seal the upper and lower sections of the filter element to be used with glue, and use medical soft PVC to melt on its left and right sides respectively to form an inlet chamber 202a and an outlet chamber 202c. The inlet chamber 202a and the outlet chamber 202c are completely separated by the filter element 202b, and an inlet pipe 201 is provided above the inlet chamber 202a, and an outlet pipe 203 is provided below the outlet chamber 202c.

[0057] The filtration chamber using the first filter element is a large-aperture filtration chamber, and the filtration chambers using the second filter element are the first small-aperture filtration chamber and the second small-aperture filtration chamber. Similarly, the large-aperture filtration chamber, the first small-aperture filtration chamber, and the second small-aperture filtration chamber are made by high-frequency heat-sealing and melting Figure 1 The filter shown in Figure 1 includes a liquid inlet pipe 201, a large-pore filtration chamber 202, a liquid equalizing device 203 provided at the liquid outlet of the large-pore filtration chamber, a first small-pore filtration chamber 204, a second small-pore filtration chamber 205, and a liquid outlet pipe 206. Among them, the first small-pore filtration chamber 204 and the second small-pore filtration chamber 205 are in parallel and are respectively connected to the liquid equalizing device 203 and the liquid outlet pipe 206 provided at the liquid outlet of the first filtration chamber. Specifically, a liquid inlet pipe 201 is provided above the large-pore filtration chamber 202 for transporting whole blood, and a liquid equalizing component 203 is provided below the large-pore filtration chamber 202 to make the whole blood in the large-pore filtration chamber 202 enter the lower filtration chamber evenly. The liquid equalizing component 203 is a plurality of vertically arranged liquid equalizing pipes. The liquid inlet ports of the first small-pore filtration chamber 204 and the second small-pore filtration chamber 205 are connected to the liquid outlet of the liquid equalizing component 203, and the whole blood is filtered by the first small-pore filtration chamber 204 and the second small-pore filtration chamber 205 and then enters the liquid outlet pipe 206 through the liquid outlet for output.

[0058] Example 2

[0059] The difference between this example and Example 1 is that the ratio of agarose, chitosan, and polyethylene glycol PEG200 in the modified preparation is 20:20:10, and the spraying ratio of the modified preparation to the second non-woven fabric is 12:88. The rest are the same as in Example 1, and a filter is obtained.

[0060] Example 3

[0061] The difference between this example and Example 1 is that the ratio of agarose, chitosan, and polyethylene glycol PEG200 in the modified preparation is 18:15:8, and the spraying ratio of the modified preparation to the second non-woven fabric is 15:85. The rest are the same as in Example 1, and a filter is obtained.

[0062] Example 4

[0063] The difference between this example and Example 1 is that the ratio of agarose, chitosan, and polyethylene glycol PEG200 in the modified preparation is 15:20:7, and the spraying ratio of the modified preparation to the second non-woven fabric is 20:80. The rest are the same as in Example 1, and a filter is obtained.

[0064] Example 5

[0065] The difference between this example and Example 1 is that the ratio of agarose, chitosan, and polyethylene glycol PEG200 in the modified preparation is 20:15:14, and the spraying ratio of the modified preparation to the second non-woven fabric is 13:87. The rest are the same as in Example 1, and a filter is obtained.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 1 is that the second non-woven fabric is not modified, and the rest are the same as those in Example 1, and a filter is obtained.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 1 is that both the first non-woven fabric and the second non-woven fabric are polyethylene terephthalate non-woven fabrics, with a basis weight of 42 g / m 2 , a thickness of 0.25 mm, a fiber diameter of about 2.0 μm, an average pore size of 14 μm, the second non-woven fabric is not modified, and the rest are the same as those in Example 1, and a filter is obtained.

[0070] Comparative Example 3

[0071] The difference between this comparative example and Example 1 is that both the first non-woven fabric and the second non-woven fabric are polyethylene terephthalate non-woven fabrics, with a basis weight of 40 g / m 2 , a thickness of 0.22 mm, a fiber diameter of about 1.5 μm, an average pore size of 5 μm, the second non-woven fabric is not modified, and the rest are the same as those in Example 1, and a filter is obtained.

[0072] Comparative Example 4

[0073] The difference between this comparative example and Example 1 is that only polyethylene glycol PEG200 is used to modify the second non-woven fabric, and the rest are the same as those in Example 1, and a filter is obtained.

[0074] Comparative Example 5

[0075] The difference between this comparative example and Example 1 is that only chitosan is used to modify the second non-woven fabric, and the rest are the same as those in Example 1, and a filter is obtained.

[0076] Test Example 1

[0077] Select 10 bags of whole blood at 200 ml / bag. The collection process of the whole blood complies with the requirements of the "Technical Operating Procedures for Blood Stations" (2019 Edition), the collection time ≤ 5 min, and it is stored in an environment of (4 ± 2)°C after collection. Use the whole blood filters prepared in Examples 1 to 5 and Comparative Examples 1 to 5 above to filter the above-mentioned whole blood, and control the filtration speed at 110 drops / minute. If the speed is too fast, the whole blood cannot fully infiltrate the filter disc when passing through the filter element, the effective filtration area of the filter disc decreases, which can cause the "flower disc" phenomenon and excessive damage to red blood cells; if the speed is too slow, it will cause blockage.

[0078] The white blood cell content was tested after filtration. The destruction of red blood cells was characterized by testing FHb (free hemoglobin). The instruments used were: XT-1800i hematology analyzer (SYSMEX Corporation), Nageotte large-volume white blood cell counting chamber (HAUSSERSCIENTIFIC HORSHAM, PAUSA), and plasma FHb kit (Beijing Ruierda Company).

[0079] The white blood cell content after filtration, the FHb before filtration (mg / L), and the FHb after filtration (mg / L) of Test Examples 1-5 and Comparative Examples 1-5 were tested, and the obtained data are listed in Table 1.

[0080] Table 1 Comparison of the results of leukocyte filtration in the examples and comparative examples of the present invention

[0081]

[0082] * The white blood cell content before filtration was approximately 4.8×10 9 (cells / unit)

[0083] As can be seen from Table 1, in Comparative Example 1, since the second non-woven fabric was not modified, the red blood cells were severely damaged; in Comparative Example 2, although the destruction of red blood cells was less, the filtration effect did not meet the standard because the pore size was relatively large and the filtration effect was not ideal; in Comparative Example 3, due to the too small pore size, although the filtration effect was very good, the red blood cells were damaged most severely; in Comparative Examples 4 and 5, only polyethylene glycol or chitosan was used for modification, and there was still a relatively serious situation of red blood cell destruction. The possible reason is that the modification effect of polyethylene glycol or chitosan alone on the non-woven fabric is not ideal. According to the above test results, after the non-woven fabric of the present invention is modified and used as a secondary filter with a small pore size, there is an obvious improvement in reducing the damage of red blood cells during leukocyte filtration.

[0084] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered by the protection scope of the present invention.

Claims

1. A filter for removing leukocytes, characterized in that: include: Inlet tube for whole blood delivery; A large-aperture filter chamber whose liquid inlet is connected to the liquid outlet of the liquid inlet pipe; A small-pore filter chamber whose liquid inlet is connected to the liquid outlet of the large-pore filter chamber; A liquid outlet pipe whose liquid inlet is connected to the liquid outlet of the small-pore filter cavity; Wherein, a first filter element is arranged in the large-aperture filter cavity; a second filter element is arranged in the small-aperture filter cavity; The second filter core comprises a second filter core body and a surface modification layer formed on the surface of the second filter core body; the surface modification layer comprises agarose, chitosan and polyethylene glycol.

2. The filter according to claim 1, characterized in that The mass ratio of agarose, chitosan and polyethylene glycol is (15-20): (10-20): (5-15).

3. The filter according to claim 1, characterized in that The mass ratio of the surface modified layer in the second filter element to the second filter element body is (5-20): (80-95).

4. The filter according to claim 1, characterized in that The molecular weight of the polyethylene glycol is 200-400.

5. The filter according to claim 1, characterized in that The small-pore filter chamber includes a second filter chamber and a third filter chamber connected in parallel.

6. The filter according to claim 1, characterized in that The first filter element comprises multiple layers of first non-woven fabric; the equivalent pore size of the first non-woven fabric is 10-15 μm; The second filter element body includes multiple layers of second non-woven fabric, and the equivalent pore size of the second non-woven fabric is 3-6 μm.

7. The filter according to claim 6, characterized in that The number of layers of the multi-layer first non-woven fabric and the multi-layer second non-woven fabric is independently selected from 5 to 30 layers.

8. The filter according to claim 6, characterized in that The materials of the first non-woven fabric and the second non-woven fabric are independently selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polyurethane, polymethacrylate, polyacrylate, polyacrylonitrile, polyvinyl acetal, polyester, polyamide, polysulfone, polystyrene, polyethylene, polypropylene, cellulose and cellulose acetate.

9. The filter according to claim 6, characterized in that The fiber diameters of the first nonwoven fabric and the second nonwoven fabric are independently selected from 0.3 to 3.0 μm.

10. The filter according to claim 1, characterized in that The liquid outlet of the large-pore filter cavity further comprises a liquid equalizing component, and the liquid equalizing component is connected to the liquid inlet of the small-pore filter cavity.

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