An ultrafiltration centrifuge tube and a manufacturing method thereof

Abstract

The application relates to an ultrafiltration centrifugal tube and a manufacturing method thereof. The ultrafiltration centrifugal tube comprises an inner tube, the inner tube comprises a center tube and a filter sheet, a lower end of the center tube is provided with a first filter surface and a filter hollow in a relative mode, the first filter surface is integrally formed with the center tube, an inner side of the first filter surface is fixed with a first diaphragm through welding, an inner side of the filter sheet is fixed with a second diaphragm through welding, the filter sheet is fixed in the filter hollow through welding inlay to form a second filter surface, the first filter surface and the second filter surface are mirror-symmetrical, the first filter surface and the second filter surface both have filter holes, the inner tube is sleeved with an outer tube, port covers of the inner tube and the outer tube are provided with tube covers, the inner tube has a liquid storage cavity, a gap cavity is formed between an outer wall of the center tube and an inner wall of the outer tube, the filter holes are communicated with the liquid storage cavity and the gap cavity, and the first diaphragm and the second diaphragm cover the filter holes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrafiltration centrifuge tube, in particular to an ultrafiltration centrifuge tube and a manufacturing method thereof. BACKGROUND

[0002] Purification of macromolecular components in tissue culture medium extract, purification of macromolecular components in cell lysate, removal of primers, ligation or molecular markers from reaction mixtures, and removal of proteins before HPLC; or desalination, buffer exchange or diafiltration, etc. all require the use of separation methods to complete.

[0003] Membrane separation is a very efficient separation method. In the field of life sciences, membrane separation gradually replaces traditional separation methods such as chemical precipitation, dialysis, and freeze-drying. However, membrane separation requires very strict assembly, and poor sealing at the local connection of the components of the assembly will cause leakage, seriously affecting the separation effect and making the experimental data unreliable. Among them, ultrafiltration is a membrane separation method that uses ultrafiltration membranes with certain retention capacity as filter media and pressure difference as power to separate very small particles and soluble molecules in the solution. Compared with traditional methods, ultrafiltration has the advantages of gentleness, convenience, rapidity, high efficiency, and is very effective for isovolumetric ultrafiltration for sample desalination and buffer replacement.

[0004] The ultrafiltration centrifuge tube is generally composed of an outer tube, a receiving tube, a receiving sleeve, an ultrafiltration membrane and the like. The receiving tube, the receiving sleeve and the ultrafiltration membrane are assembled in the outer tube, the ultrafiltration membrane is arranged in close contact with the filter hole on the surface of the receiving tube, and the receiving sleeve cooperates with the receiving tube to fix the ultrafiltration membrane. In use, the ultrafiltration centrifuge tube containing the filter stock solution is placed in a centrifuge for centrifugation. After the centrifuge is started, the filter stock solution is continuously supplemented into the receiving tube. In this way, the filter stock solution is separated by the ultrafiltration membrane under the action of the centrifuge and is thrown into the bottom cavity of the outer tube, thereby realizing membrane separation.

[0005] The ultrafiltration centrifuge tube has the function of rapid ultrafiltration, can achieve a high concentration coefficient, and is easy to recover concentrated liquid from dilute liquid and complex sample combinations, so it is widely used in the field of biological filtration. The ultrafiltration centrifuge tube is mainly used for concentrating biological samples containing antigens, antibodies, enzymes, nucleic acids (single or double DNA / RNA samples), microorganisms, eluate and purified samples.

[0006] However, the existing ultrafiltration centrifuge tube still has a series of problems.

[0007] Existing ultrafiltration centrifuge tubes mostly use silicone sealing rings or adhesives to seal with plastic parts. When using silicone rings for sealing, leakage is prone to occur after centrifugal force during use; when using adhesives for sealing, adhesive residue is likely to remain, increasing the amount of dissolved substances and affecting the final test results; moreover, the curing time of adhesives is long, resulting in low efficiency during sealing assembly. These existing methods have a poor user experience and also affect the separation effect and the impurity content of the finished product. Summary of the Invention

[0008] Therefore, it is necessary to provide an ultrafiltration centrifuge tube and its manufacturing method.

[0009] One embodiment of the present invention provides an ultrafiltration centrifuge tube, including an inner tube, the inner tube including a central tube and a filter plate, the lower end of the central tube having a first filter surface and a filter perforation respectively, the first filter surface being integrally formed with the central tube, a first membrane being fixed to the inner side of the first filter surface by welding, a second membrane being fixed to the inner side of the filter plate by welding, the filter plate being fixed to the filter perforation by welding to form a second filter surface, the first filter surface and the second filter surface being mirror symmetrical, both the first filter surface and the second filter surface having filter holes, an outer tube being fitted over the inner tube, the ends of the inner tube and the outer tube being covered with tube caps, the inner tube having a liquid storage chamber, a gap cavity being formed between the outer wall of the central tube and the inner wall of the outer tube, the filter holes communicating with the liquid storage chamber and the gap cavity, the first membrane and the second membrane covering the filter holes.

[0010] Preferably, both the first membrane and the second membrane are ultrafiltration membranes, and the ultrafiltration membranes are flat sheet ultrafiltration membranes.

[0011] Preferably, an annular membrane welding area is provided on the inner side of the central tube around the periphery of the first filter surface. The first membrane covers the first filter surface of the central tube, and the periphery of the first membrane is aligned and covers the membrane welding area, thereby fixing the first membrane by welding.

[0012] Preferably, an annular filter element welding area is provided on the outer side of the central tube at the periphery of the filter perforation, and the membrane filter element is embedded in the filter perforation so that the periphery of the membrane filter element covers the filter element welding area, and the membrane filter element is fixed by welding.

[0013] Preferably, the filter element has a stepped surface formed around its periphery, the stepped surface abutting against the welding area of ​​the filter element, and the stepped surface and the welding area of ​​the filter element are fixed by welding.

[0014] Preferably, the welding method includes one of hot melt welding, high-frequency welding, ultrasonic welding, and laser welding.

[0015] Preferably, the inner tube and the outer tube are concentrically arranged, the outer edge of the inner tube's opening rests on the inner edge of the outer tube's opening, a positioning groove is provided at the inner edge of the outer tube's opening, and a positioning block is provided at the corresponding outer edge of the inner tube's opening, the positioning block being aligned and resting in the positioning groove.

[0016] Preferably, the outer surface of the pipe cap is provided with an anti-roll protrusion, which protrudes above the outer surface of the pipe cap and forms an anti-roll plane.

[0017] Preferably, the anti-roll plane is perpendicular to the line connecting the center of the tube cap.

[0018] On the other hand, a method for manufacturing an ultrafiltration centrifuge tube is also provided, comprising the following steps:

[0019] S1. A one-piece molded central tube is manufactured;

[0020] S2. The filter sheet is manufactured such that the shape and size of the filter sheet match the filter perforation. The second membrane is covered on the inner side of the filter sheet and fixed by welding to obtain a membrane-coated filter sheet.

[0021] S3. Cover the first diaphragm with the first filter surface of the central tube, so that the periphery of the first diaphragm is aligned and covers the welding area of ​​the diaphragm, and fix the first diaphragm by welding.

[0022] S4. The membrane-coated filter sheet from step S2 is embedded in the filter cutout, so that the periphery of the membrane-coated filter sheet covers the welding area of ​​the filter sheet, and the membrane-coated filter sheet is fixed by welding to obtain the inner tube of the ultrafiltration centrifuge tube.

[0023] S5. Perform an airtightness test on the inner tube manufactured in step S4. If the airtightness is qualified, assemble it with the outer tube and the tube cap to obtain an ultrafiltration centrifuge tube.

[0024] The present invention provides an efficient method for sealing and fixing ultrafiltration centrifuge tubes and stable and reliable separation membranes with plastic parts, which avoids leakage problems during high-speed centrifugation of ultrafiltration centrifuge tubes, while shortening the welding process and improving the product yield. Attached Figure Description

[0025] The above and other objects, features, and advantages of the invention will become clearer through a more detailed description of the preferred embodiments illustrated in the accompanying drawings. The same reference numerals denote the same parts throughout the drawings, and the drawings are not intentionally drawn to scale with actual dimensions; the focus is on illustrating the gist of the invention.

[0026] Figure 1 This is a perspective view of the inner tube according to a preferred embodiment of the present invention;

[0027] Figure 2 This is a side view of the inner tube according to a preferred embodiment of the present invention;

[0028] Figure 3 for Figure 2 Sectional view at point AA';

[0029] Figure 4 This is a perspective view of the central tube according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the outer tube structure according to an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the pipe cap structure according to an embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of the pipe cap from another perspective of an embodiment of the present invention;

[0033] Outer tube 1; Inner tube 2; Central tube 3; Filter plate 4; First filter surface 5; First membrane 7; Membrane welding area 10; Filter perforation 9; Second filter surface 6; Filter plate welding area 11; Tube cap 20; Anti-roll boss 14; Anti-roll plane 15; Positioning block 17; Positioning groove 18; Liquid storage chamber 19; Air pressure balance port 21. Detailed Implementation

[0034] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0035] like Figures 1-7As shown, an ultrafiltration centrifuge tube includes an inner tube 2, which includes a central tube 3 and a filter plate 4. The lower end of the central tube 3 is provided with a first filter surface 5 and a filter perforation 9. The first filter surface 5 is integrally formed with the central tube 3. A first membrane 7 is fixed to the inner side of the first filter surface 5 by welding. A second membrane 4 is fixed to the inner side of the filter plate 4 by welding. The filter plate 4 is fixed to the filter perforation 9 by welding to form a second filter surface 6. The first filter surface 5 and the second filter surface 6 are mirror symmetrical. Both the first filter surface 5 and the second filter surface 6 have filter holes. An outer tube 1 is fitted over the inner tube 2. The ports of the inner tube 2 and the outer tube 1 are covered with tube caps 20. The inner tube 2 has a liquid storage chamber 19. A gap cavity is formed between the outer wall of the central tube 3 and the inner wall of the outer tube 1. The filter holes are connected to the liquid storage chamber 19 and the gap cavity. The first membrane 7 and the second membrane cover the filter holes on the first filter surface 5 and the second filter surface 6, respectively. Compared to existing ultrafiltration tubes that use adhesives and sealing rings to seal the ultrafiltration membrane, this invention uses a one-piece molding and welding method to fix the ultrafiltration membrane. This results in higher structural strength for the fixing structure of the first filter surface 5 and the second filter surface 6, allowing it to withstand higher centrifugation speeds, achieve faster filtration, and reduce the risk of leakage. Furthermore, by avoiding the use of adhesives to fix the ultrafiltration tube, the filtrate has extremely low leachate content, resulting in better biocompatibility. Both the first membrane sheet 7 and the second membrane sheet are cut from ultrafiltration membranes.

[0036] In a preferred embodiment, both the first membrane 7 and the second membrane are flat-sheet ultrafiltration membranes; preferably, the flat-sheet ultrafiltration membrane is a PES ultrafiltration membrane with non-woven fabric support; optionally, the central tube 3 and the filter sheet 4 are both made of plastic. Preferably, the central tube and the filter sheet forming the same inner tube are made of the same material. The material of the central tube and the filter sheet is any one of polystyrene (PS), polypropylene (PP), polystyrene-butadiene copolymer (SBR), and polystyrene-butadiene-acrylonitrile copolymer (ABS); or, the material of the central tube and the filter sheet is a blend of any two or more of the above materials.

[0037] In a preferred embodiment, an annular membrane welding area 10 is provided on the inner side of the central tube 3 at the periphery of the first filter surface 5. The first membrane 7 covers the first filter surface 5 of the central tube 3, and the periphery of the first membrane 7 is aligned and covers the membrane welding area 10. The first membrane 7 is fixed to the inner side of the first filter surface 5 of the central tube 3 by welding.

[0038] In a preferred embodiment, an annular filter plate welding area 11 is provided on the outer side of the central tube 3 around the filter perforation 9. The membrane-coated filter plate 4 is embedded in the filter perforation 9, so that the periphery of the membrane-coated filter plate 4 covers the filter plate welding area 11, and the membrane-coated filter plate 4 is fixed by welding. The inner tube 2 of the present invention makes the first filter surface 5 integrally formed with the central tube 3. At the same time, the filter plate 4 on the opposite side is fixed to the central tube by embedding and welding, ensuring sealing performance. The ultrafiltration centrifuge tube provided by the present invention ensures the sealing performance between the membrane and the filter plate, and between the filter plate and the centrifuge tube, avoiding leakage problems during high-speed centrifugation of the ultrafiltration centrifuge tube and ensuring the retention rate of the liquid. In addition, the structural improvement reduces the sealing assembly process of the parts, thereby improving efficiency and making the product qualification rate higher.

[0039] In a preferred embodiment, a stepped surface is formed around the periphery of the filter element 4, and the stepped surface abuts against the welding area 11 of the filter element. The stepped surface and the welding area 11 of the filter element are fixed by welding.

[0040] In a preferred embodiment, the welding method includes one of hot melt welding, high-frequency welding, ultrasonic welding, and laser welding.

[0041] In a preferred embodiment, the inner tube 2 and the outer tube 1 are arranged concentrically. The outer edge of the opening of the inner tube 2 is placed at the inner edge of the opening of the outer tube 1. A positioning groove 18 is provided at the inner edge of the opening of the outer tube 1. A positioning block 17 is provided at the corresponding outer edge of the opening of the inner tube 2. The positioning block 17 is aligned and placed in the positioning groove 18.

[0042] In a preferred embodiment, the outer surface of the tube cap 20 is provided with an anti-roll protrusion 14, which protrudes above the outer surface of the tube cap 20 and forms an anti-roll plane 15. The tube cap 20 has the anti-roll protrusion 14, and the tube cap 20 is fastened to the inner tube and the outer tube by threads. The anti-roll protrusion 14 can prevent the ultrafiltration centrifuge tube from rolling when placed on a table. At the same time, there is an angle between the axis of the ultrafiltration centrifuge tube and the table, which makes storage more convenient, prevents liquid from flowing out when laid flat, and prevents the membrane surface from drying out, resulting in pore shrinkage or cracking.

[0043] In a preferred embodiment, the line connecting the anti-roll plane 15 and the center of the tube cap 20 is perpendicular.

[0044] The method for manufacturing ultrafiltration centrifuge tubes is characterized by comprising the following steps:

[0045] S1, the central tube 3 obtained by integral molding;

[0046] S2. A filter sheet 4 is manufactured so that the shape and size of the filter sheet 4 match the shape of the filter perforation 9. A second membrane is placed over the inner side of the filter sheet 4 and fixed by welding to obtain a membrane-coated filter sheet 4.

[0047] S3. Cover the first diaphragm 7 on the first filter surface 5 of the central tube 3, so that the periphery of the first diaphragm 7 is aligned and covers the diaphragm welding area 10, and fix the first diaphragm 7 by welding.

[0048] S4. The membrane-coated filter 4 from step S2 is embedded in the filter cutout 9, so that the periphery of the membrane-coated filter 4 covers the filter welding area 11, and the membrane-coated filter 4 is fixed by welding to obtain the inner tube 2 of the ultrafiltration centrifuge tube.

[0049] S5. The inner tube 2 manufactured in step S4 is subjected to an airtightness test. If the airtightness is qualified, it is assembled with the outer tube and the tube cap to obtain the ultrafiltration centrifuge tube. The first filter surface 5 is integrally formed with the central tube 3. This integrally formed structure does not require secondary welding, reducing one welding process. Compared with the welded structure ultrafiltration tubes on the market, only one welding of the filter sheet is required. That is, the filter sheet 4 is embedded in the filter hole 9 and the membrane-coated filter sheet 4 is fixed by welding, which simplifies the process, improves production efficiency, and increases the product qualification rate.

[0050] It should be noted that when conducting an airtightness test by detecting the airtightness leakage of the inner tube 2, if the airtightness leakage is lower than the set value, it is determined that the airtightness is qualified.

[0051] It should be noted that the inner tube 2 includes an upper cylindrical section for storing liquid and a lower end for filtering the internal liquid. Both the inner tube 2 and the outer tube 1 are capped with a cap 20, which simultaneously seals both the inner tube 2 and the outer tube 1. The cap 20 prevents the liquid in the storage chamber 19 and the interstitial chamber from being ejected from the centrifuge tube assembly during centrifugation. During centrifugation, the liquid filtered through the membrane in the storage chamber 19 gradually passes through the filter holes into the interstitial chamber, thereby achieving functions such as protein concentration and desalting, buffer replacement, collection of proteins or other molecules from cell supernatant or lysate, and removal of large molecular particles.

[0052] To better illustrate the technical solution of the present invention, several embodiments are now provided to further explain its effects.

[0053] Example 1

[0054] The plastic parts are produced according to the structure and manufacturing method described in this application, including a central tube and a filter sheet.

[0055] A 30kD PES ultrafiltration membrane with nonwoven fabric support is cut into membrane sheets. These sheets are then thermally welded to the membrane sheet welding area of ​​the central tube. Simultaneously, an ultrafiltration membrane is welded to the membrane sheet welding area of ​​the filter element. The filter element is then ultrasonically welded to the filter element welding area of ​​the central tube. The inner tube of the ultrafiltration tube is now complete.

[0056] (1) The inner tube is tested for air tightness.

[0057] The completed inner tube is tested for air tightness using an air tightness tester to detect gas leakage. The air tightness is considered qualified if the leakage rate is ≤0.3mL / min.

[0058] The parameters for the airtightness test are: inflation time set to 10s, pressure holding time set to 15s, and pressure holding pressure set to 200kPa.

[0059] Fifty inner tube samples were randomly selected for airtightness testing, and the airtightness test data are shown in Table 1 below:

[0060] Table 1

[0061]

[0062] As shown in Table 1, the air tightness test results of 50 inner tube samples all showed an air tightness leakage of less than 0.3 mL / min. This indicates that the inner tubes produced using the centrifuge tube structure and manufacturing method of the present invention have excellent air tightness and a high product qualification rate.

[0063] (2) Test the BSA rejection rate of the ultrafiltration tube.

[0064] Twenty-four inner tubes were extracted from the 50 inner tube samples that underwent airtightness testing and had an airtightness leakage rate of less than 0.3 mL / min, and assembled with the outer tube and cap prepared according to the method and structure of this application to form 24 ultrafiltration tubes.

[0065] The BSA rejection rate of these 24 ultrafiltration tubes was tested using a centrifuge:

[0066] The protein solutions were all 1000 mg / L BSA solutions. Twenty-four ultrafiltration tubes were randomly divided into three groups of eight. The centrifuge forces were set to 2000 × g, 3000 × g, and 4000 × g, respectively, with the same centrifugation time for all three groups. The average values ​​of the data from the eight tubes in each group were used to obtain the test results shown in Table 2 below.

[0067] Table 2

[0068] Centrifugal force 2000×g 3000×g 4000×g Average % Retention 98.6 98.4 98.3 Average % Recovery 93.2 92.8 92.4

[0069] The data on the rejection rate in Table 2 above indicate that the inner tube packaging has good sealing performance, and there is no cracking or leakage at the welding positions of the membrane and filter under high-speed centrifugation.

[0070] Example 2

[0071] The plastic parts are produced according to the structure and manufacturing method described in this application, including a central tube and a filter sheet.

[0072] A 10kD PES ultrafiltration membrane with nonwoven fabric support is cut into membrane sheets. These sheets are then thermally welded to the membrane welding area of ​​the central tube. Simultaneously, an ultrafiltration membrane is welded to the membrane welding area of ​​the filter element. The filter element is then ultrasonically welded to the filter welding area of ​​the central tube. The inner tube of the ultrafiltration tube is now complete.

[0073] (1) The inner tube is tested for air tightness.

[0074] The completed inner tube is tested for air tightness using an air tightness tester to detect gas leaks.

[0075] The parameters for the airtightness test are: inflation time set to 10s, pressure holding time set to 15s, and pressure holding pressure set to 200kPa.

[0076] One hundred inner tube samples were randomly selected for airtightness testing, and the airtightness test data are shown in Table 3 below:

[0077] Table 3

[0078]

[0079] Using an airtightness leakage rate of ≤0.3mL / min as the standard for airtightness compliance, the results in Table 3 show that the pass rate of 100 inner tube samples was 99%.

[0080] (2) Test the cytochrome C retention rate of the ultrafiltration tube.

[0081] Thirteen qualified inner tubes were selected from 100 inner tube samples that underwent airtightness testing and had an airtightness leakage rate of less than 0.3 mL / min. These inner tubes were then assembled with the outer tubes and caps prepared according to the method and structure of this application to form 13 qualified ultrafiltration tubes; this constitutes a qualified ultrafiltration tube assembly.

[0082] Simultaneously, one substandard inner tube with an airtightness leakage rate greater than 0.3 mL / min was assembled with the outer tube and cap prepared according to the method and structure of this application to form a substandard ultrafiltration tube. This constitutes a substandard ultrafiltration tube assembly.

[0083] All solutions were 1000 mg / L cytochrome C solution; the centrifugal force was set to 2000 × g; the centrifugation time was the same for both qualified and unqualified ultrafiltration tube groups. The cytochrome C retention data for the ultrafiltration tubes were obtained as shown in Table 4 below.

[0084] Table 4

[0085] Ultrafiltration tube type Passing ultrafiltration tubes Failing ultrafiltration tubes Average % Retention 96.8 86.3 Average % Recovery 91.3 79.2

[0086] As can be seen from the retention rate data in Table 4, qualified ultrafiltration tubes have very high retention and recovery rates, both >90%, and can effectively retain cytochrome C. Unqualified ultrafiltration tubes have lower cytochrome C retention.

[0087] Example 3

[0088] The corresponding plastic parts are produced according to the above structure and manufacturing method. The plastic parts include a central tube and a filter sheet.

[0089] A 3kD PES ultrafiltration membrane with nonwoven fabric support is thermally welded to the membrane welding area of ​​the central tube. Simultaneously, an ultrafiltration membrane is welded to the membrane welding area of ​​the filter element. The filter element is then ultrasonically welded to the filter element welding area of ​​the central tube. The inner tube of the ultrafiltration tube is now complete.

[0090] (1) The inner tube is tested for air tightness.

[0091] The completed inner tube is tested for air tightness using an air tightness tester to detect gas leakage. The air tightness is considered qualified if the leakage rate is ≤0.3mL / min.

[0092] The parameters for the airtightness test are: inflation time set to 10s, pressure holding time set to 15s, pressure holding pressure set to 200kPa, and gas leakage detected.

[0093] The airtightness of the above 30 inner tube samples was tested, and the airtightness test data are shown in Table 5 below:

[0094] Table 5

[0095]

[0096] Based on the results of the airtightness test in Table 1, the pass rate of the inner tube samples in this test was 100%.

[0097] (2) Test the cytochrome C retention rate of the ultrafiltration tube.

[0098] Fourteen tubes were selected from the 30 inner tube samples that underwent airtightness testing and passed the airtightness test, and assembled into 14 ultrafiltration tubes to test cytochrome C retention:

[0099] All solutions were 1000 mg / L cytochrome C solution; 14 ultrafiltration tubes were randomly divided into two groups of 7 tubes each; the centrifugation time was the same for both groups, and the retention data are shown in Table 6 below:

[0100] Table 6

[0101] Centrifugal force Fixed angle centrifuge 4000 x g Swinging bucket centrifuge 5000 x g Average % Retention 96.8 96.6 Average % Recovery 91.3 91.2

[0102] As can be seen from the data in Table 6, the qualified ultrafiltration tubes have very high rejection and recovery rates, both exceeding 90%, and can effectively retain cytochrome C.

[0103] Example 4

[0104] The plastic parts are produced according to the structure and manufacturing method described in this application, including a central tube and a filter sheet.

[0105] A 50kD PES ultrafiltration membrane with nonwoven fabric support is cut into membrane sheets. These sheets are then thermally welded to the membrane sheet welding area of ​​the central tube. Simultaneously, an ultrafiltration membrane is welded to the membrane sheet welding area of ​​the filter sheet. The filter sheet is then ultrasonically welded to the filter sheet welding area of ​​the central tube. The inner tube of the ultrafiltration tube is now complete.

[0106] (1) The inner tube is tested for air tightness.

[0107] The completed inner tube is tested for air tightness using an air tightness tester to detect gas leakage. The air tightness is considered qualified if the leakage rate is ≤0.3mL / min.

[0108] The parameters for the airtightness test are: inflation time set to 10s, pressure holding time set to 15s, and pressure holding pressure set to 200kPa.

[0109] One hundred inner tube samples were randomly selected for airtightness testing, and the airtightness test data are shown in Table 7 below:

[0110] Table 7

[0111]

[0112] Based on the results of the airtightness test in Table 7, the pass rate of the samples produced this time was 98%.

[0113] (2) Test the BSA rejection rate of the ultrafiltration tube.

[0114] Fourteen inner tubes were extracted from the above-mentioned airtight samples to make fourteen ultrafiltration tubes for testing the 1000 mg / L BSA retention. The retention data are shown in Table 8 below:

[0115] Table 8

[0116] Centrifugal force Fixed angle centrifuge 4000 x g Swinging bucket centrifuge 5000 x g Average % Retention 94.3 94.6 Average % Recovery 90.6 90.8

[0117] As shown in Table 8, the ultrafiltration tubes with qualified airtightness have very high rejection and recovery rates, both exceeding 90%, and can effectively retain BSA.

[0118] Example 5

[0119] The plastic parts are produced according to the structure and manufacturing method described in this application, including a central tube and a filter sheet.

[0120] A 100kD PES ultrafiltration membrane with nonwoven fabric support is cut into membrane sheets. These sheets are then thermally welded to the membrane sheet welding area of ​​the central tube. Simultaneously, an ultrafiltration membrane is welded to the membrane sheet welding area of ​​the filter sheet. The filter sheet is then ultrasonically welded to the filter sheet welding area of ​​the central tube. The inner tube of the ultrafiltration tube is now complete.

[0121] (1) The inner tube is tested for air tightness.

[0122] The inner tube that has been made above is tested for air tightness on an air tightness tester to detect gas leakage. The air tightness is qualified if the leakage rate is ≤0.3mL / min.

[0123] The parameters for the airtightness test are: inflation time set to 10s, pressure holding time set to 15s, and pressure holding pressure set to 200kPa.

[0124] A total of 200 inner tube samples were collected for airtightness testing, and the airtightness test data are shown in Table 9 below:

[0125] Table 9

[0126]

[0127] Our internal standard is that a leakage rate of ≤0.3mL / min for a 50kD ultrafiltration tube is acceptable. The pass rate of the samples produced this time was 97%.

[0128] (2) Test the IGG rejection rate of the ultrafiltration tube.

[0129] Fourteen inner tube samples were randomly selected from the 200 inner tube samples that underwent airtightness testing and passed the airtightness test to assemble ultrafiltration tubes. The retention of 1000 mg / L IGG solution was tested, and the retention data are shown in Table 10 below:

[0130] Table 10

[0131] Centrifugal force Fixed angle centrifuge 4000 x g Swinging bucket centrifuge 5000 x g Average % Retention 98.6 97.8 Average % Recovery 93.6 92.7

[0132] (3) Ultrafiltration tube reuse test

[0133] Fourteen ultrafiltration tubes used in the IGG rejection test described in (2) above were reused to test the IGG rejection rate. After each filtration, the tubes were soaked in a 1 mol / L sodium hydroxide solution for 10 minutes, then rinsed with pure water before being used to filter protein solutions. This process was repeated for 20 cycles, and the changes in rejection rate and airtightness of each ultrafiltration tube were measured. The data are shown in Table 11 below:

[0134] Table 11

[0135] First centrifugation 20th centrifugation Air tightness ＜0.3 ＜0.3 Average % Retention 98.6 98.8

[0136] As can be seen from Table 11 above, the rejection rate did not change significantly after 20 centrifugations, and the airtightness also remained unchanged. This indicates that the structure and method of the centrifuge tube of the present invention result in a high connection strength of the inner tube.

[0137] In summary, based on the data from Examples 1-5, the qualified ultrafiltration tubes exhibit very high retention and recovery rates, both exceeding 90%, effectively retaining the target protein (i.e., IGG).

[0138] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. An ultrafiltration centrifuge tube, characterized in that, The device includes an inner tube, which comprises a central tube and a filter element. The lower end of the central tube has a first filter surface and a filter perforation. The first filter surface is integrally formed with the central tube. A first membrane is welded to the inner side of the first filter surface, and a second membrane is welded to the inner side of the filter element. The filter element is welded and embedded within the filter perforation to form a second filter surface. The first and second filter surfaces are mirror-symmetrical and each has filter holes. An outer tube is fitted over the inner tube. Both the inner and outer tubes are capped. The inner tube contains a liquid storage chamber. A gap cavity is formed between the outer wall of the central tube and the inner wall of the outer tube. The filter holes connect the liquid storage chamber and the gap cavity. The first and second membranes cover the filter holes. The inner tube and the outer tube are concentrically arranged. The outer edge of the inner tube's opening rests on the inner edge of the outer tube's opening. A positioning groove is provided at the inner edge of the outer tube's opening. Correspondingly, a positioning block is provided at the outer edge of the inner tube's opening. The positioning block is aligned and rests in the positioning groove. The outer surface of the pipe cap is provided with an anti-roll protrusion, which is higher than the outer surface of the pipe cap and forms an anti-roll plane; the anti-roll plane is perpendicular to the line connecting the center of the pipe cap. The method for manufacturing the ultrafiltration centrifuge tube includes the following steps: S1. A one-piece molded central tube is manufactured; S2. The filter sheet is manufactured such that the shape and size of the filter sheet match the filter perforation. The second membrane is covered on the inner side of the filter sheet and fixed by welding to obtain a membrane-coated filter sheet. S3. Cover the first diaphragm with the first filter surface of the central tube, so that the periphery of the first diaphragm is aligned and covers the welding area of ​​the diaphragm, and fix the first diaphragm by welding. S4. The membrane-coated filter sheet from step S2 is embedded in the filter cutout, so that the periphery of the membrane-coated filter sheet covers the welding area of ​​the filter sheet, and the membrane-coated filter sheet is fixed by welding to obtain the inner tube of the ultrafiltration centrifuge tube. S5. Perform an airtightness test on the inner tube manufactured in step S4. If the airtightness is qualified, assemble it with the outer tube and the tube cap to obtain an ultrafiltration centrifuge tube.

2. The ultrafiltration centrifuge tube as described in claim 1, characterized in that, Both the first membrane and the second membrane are ultrafiltration membranes, and the ultrafiltration membranes are flat sheet ultrafiltration membranes.

3. The ultrafiltration centrifuge tube as described in claim 1, characterized in that, An annular membrane welding area is provided on the inner side of the central tube at the periphery of the first filter surface. The first membrane covers the first filter surface of the central tube, and the periphery of the first membrane is aligned and covers the membrane welding area. The first membrane is fixed by welding.

4. The ultrafiltration centrifuge tube as described in claim 3, characterized in that, An annular filter welding area is provided on the outer side of the central tube at the periphery of the filter cutout. The membrane filter is embedded in the filter cutout, so that the periphery of the membrane filter covers the filter welding area, and the membrane filter is fixed by welding.

5. The ultrafiltration centrifuge tube as described in claim 1, characterized in that, The filter element has a stepped surface formed around its periphery, which abuts against the welding area of ​​the filter element, and the stepped surface is fixed to the welding area of ​​the filter element by welding.

6. The ultrafiltration centrifuge tube as described in claim 1, characterized in that, The welding method includes one of the following: hot melt welding, high-frequency welding, ultrasonic welding, and laser welding.

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