An ultrafiltration centrifuge tube and an inner tube thereof

Abstract

The application provides an ultrafiltration tube and an inner tube thereof, the inner tube comprising a cylindrical part, a filter part being arranged at the lower end of the cylindrical part, the filter part having a filter cavity, a first filter surface and a second filter surface being oppositely arranged at the side surface of the filter part, a filter membrane being arranged at the first filter surface and the second filter surface, an embedded core being arranged in the filter cavity, the embedded core being located between the first filter surface and the second filter surface, the front surface of the embedded core having a first surface, the back surface of the embedded core having a second surface, the first surface being opposite to the first filter surface so that a first gap is formed between the first surface and the first filter surface, the second surface being opposite to the second filter surface so that a second gap is formed between the second surface and the second filter surface.

Description

Technical Field

[0001] This invention relates to the field of centrifuge tubes, and particularly to an ultrafiltration centrifuge tube and its inner tube. Background Technology

[0002] In the life sciences, membrane separation has become a highly efficient separation method, gradually replacing traditional methods such as chemical precipitation, dialysis, and lyophilization. Ultrafiltration centrifuge tubes are commonly used membrane separation tools in laboratories, primarily for the concentration, desalting, buffer replacement, or purification of biological macromolecules. Ultrafiltration centrifuge tubes utilize centrifugal force to drive the solution through the pore size of the filter membrane, selectively retaining large molecules such as proteins in the upper layer, forming a retention solution, while smaller molecules such as salts and water are filtered out to the lower layer, yielding the filtrate. In use, the sample solution to be processed is injected into the upper layer of the ultrafiltration centrifuge tube, and the corresponding centrifugal force and time are set. After centrifugation, the upper layer of the ultrafiltration centrifuge tube is the retention solution concentrated with the target macromolecules, while the lower layer is the filtrate composed of the filtered-out small molecules and the solvent.

[0003] Ultrafiltration centrifuge tubes are classified into two types based on the placement of the filter membrane in their main structure: one type has the filter membrane placed horizontally, and the other has the filter membrane placed vertically. Due to structural limitations, horizontally placed membranes typically have a smaller membrane area and are prone to concentration polarization, leading to increasingly slower filtration speeds and reduced filtration efficiency. Therefore, most commercially available ultrafiltration centrifuge tubes use a near-vertical vertical placement of the filter membrane. Centrifuge tubes with vertically placed membranes have a larger membrane area, reduce membrane fouling caused by concentration polarization, and have a faster filtration speed than the former.

[0004] However, vertical placement of the filter membrane also has its drawbacks: during centrifugation, as the upper layer of liquid gradually concentrates and decreases, when the liquid decreases to a certain extent due to the continuous filtration of small molecules and solvents to the lower layer, the membrane surface at the top of the centrifuge tube can no longer be completely wetted by the remaining liquid and is exposed. As a result, the membrane surface wetted by the remaining liquid decreases, the filtration area gradually decreases, the filtration speed also decreases, the filtration speed slows down in the later stages, resulting in a long overall filtration time, and it can also lead to concentration polarization and membrane fouling.

[0005] In the prior art, although some ultrafiltration centrifuge tubes with improved new structures have emerged to improve these defects of vertical filter membranes, such as the new patent CN205253154U which discloses an ultrafiltration centrifuge tube, the ultrafiltration centrifuge tube includes a sample receiving chamber, a filter plate, a filter membrane, a tube cap, and a filter recovery tube. The sample receiving chamber includes an upper chamber and a lower chamber. The upper chamber forms a sample storage chamber and has a sample inlet opening on its upper end face. The lower chamber includes a dead end and an outer frame wall. The outer frame wall forms a filter chamber. The dead end is located at the bottom of the outer frame wall to prevent the sample from drying out during centrifugation filtration. The filter plate includes a filter membrane support block and a lower edge. The filter membrane support block is in the shape of an inner quadrilateral to provide more filtration area. A guide channel is provided on the upper surface of the filter membrane support block, and multiple drainage holes are provided at the lower end of the guide channel. Although the existing patent has improved the filtration area and efficiency to some extent, these patents on the market have very limited improvement in filtration speed, the overall filtration time is still very long, and they cannot solve the membrane fouling problem caused by concentration polarization. Summary of the Invention

[0006] Therefore, it is necessary to provide an ultrafiltration tube and its inner tube.

[0007] To solve the above-mentioned technical problems, the present invention provides an ultrafiltration tube inner tube, including a cylindrical part, a filtration part at the lower end of the cylindrical part, the filtration part having a filtration cavity, a first filtration surface and a second filtration surface disposed opposite each other on the sides of the filtration part, a filter membrane disposed at the first filtration surface and the second filtration surface, an embedded core disposed in the filtration cavity, the embedded core being located between the first filtration surface and the second filtration surface, the front side of the embedded core having a first surface, the back side of the embedded core having a second surface, the first surface being directly opposite the first filtration surface such that a first gap exists between the first surface and the first filtration surface, and the second surface being directly opposite the second filtration surface such that a second gap exists between the second surface and the second filtration surface.

[0008] Preferably, the embedded core has a liquid extraction groove, the opening of which faces the side where the port of the inner tube is located, and the first gap and the second gap are respectively connected to the liquid extraction groove.

[0009] Preferably, the shape of the liquid collection tank gradually decreases from top to bottom, so that the shape of the liquid collection tank matches the shape of the pipette tip.

[0010] Preferably, the first filter surface and the vertical direction are at an angle, and the second filter surface and the vertical direction are at an angle, and the first filter surface and the second filter surface are mirror images of each other.

[0011] Preferably, the embedded core and the inner tube are integrally formed, and the included angle ranges from 1 to 10°.

[0012] Preferably, the first surface is parallel to the first filter surface, the second surface is parallel to the second filter surface, and the gap width of the first gap and the second gap is 0.05-1.5mm.

[0013] Preferably, the gap width of the first gap and the second gap is 0.1-0.4 mm.

[0014] Preferably, the embedded core is detachably installed inside the inner tube, and the shape and size of the embedded core match the shape and size of the filter cavity, so that the two sides of the embedded core are respectively aligned and fitted into the two ends of the filter cavity.

[0015] Preferably, the inner wall of the inner tube is provided with limiting grooves on both sides opposite to each other, the limiting grooves are arranged in the vertical direction, the two sides of the inner core are respectively embedded in the limiting grooves, and the two sides of the inner core are interference fit with the limiting grooves.

[0016] On the other hand, an ultrafiltration centrifuge tube is also provided, including the inner tube, an outer tube sleeved on the outside of the inner tube, a filtrate cavity formed between the outer wall of the inner tube and the inner wall of the outer tube, and a tube cap covering the ports of the inner tube and the outer tube, and the inner tube and the outer tube are concentrically arranged.

[0017] The beneficial effects of this invention are as follows: By improving the structure of the inner tube, this invention increases the liquid disturbance and turbulence on the membrane surface, which greatly improves the utilization of the membrane area during the concentration process, reduces membrane fouling, increases the filtration speed, and shortens the separation and concentration time. Attached Figure Description

[0018] 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.

[0019] Figure 1 This is a perspective view of the central tube with an embedded core in Embodiment 1 of the present invention;

[0020] Figure 2 This is a front view of the central tube with an embedded core in Embodiment 1 of the present invention;

[0021] Figure 3 for Figure 2 Cross-sectional view of the central tube at point AA;

[0022] Figure 4 for Figure 2 Cross-sectional view of the central tube at the FF point;

[0023] Figure 5 This is a side view of the central tube with an embedded core in Embodiment 1 of the present invention;

[0024] Figure 6 for Figure 5 Cross-sectional view at point BB;

[0025] Figure 7 This is a top view of the central tube in Embodiment 1 of the present invention;

[0026] Figure 8 This is a cross-sectional view of the inner tube according to Embodiment 1 of the present invention;

[0027] Figure 9 This is a perspective view of the inner tube according to Embodiment 1 of the present invention;

[0028] Figure 10 This is a schematic diagram of the outer tube from the front view in Embodiment 1 of the present invention;

[0029] In the figure: Inner tube 1; Cylindrical part 2; Filter part 3; First filter surface 31; Second filter surface 32; Filter chamber 4; Membrane filter 5; Filter membrane 51; Filter sheet 53; Inner core 6; First gap 71; Second gap 72; Outer tube 8; Filter sheet welding position 12; Liquid collection tank 13; Central tube 14. Detailed Implementation

[0030] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings.

[0031] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to and integrated with the other component, or there may be an intervening component present. The terms "mounted," "one end," "the other end," and similar expressions used in this document are for illustrative purposes only.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] refer to Figures 1-10This invention provides an inner tube 1 for an ultrafiltration tube, including a cylindrical portion 2. A filtration portion 3 is disposed at the lower end of the cylindrical portion 2. The filtration portion 3 has a filtration cavity 4 inside. A first filtration surface 31 and a second filtration surface 32 are disposed opposite each other on the sides of the filtration portion 3. A filter membrane 51 is disposed at the first filtration surface 31 and the second filtration surface 32. An embedded core 6 is disposed within the filtration cavity 4, located between the first filtration surface 31 and the second filtration surface 32. The front side of the embedded core 6 has a first surface, and the back side of the embedded core has a second surface. The first surface faces the first filtration surface 31, creating a first gap 71 between the first surface and the first filtration surface 31. The second surface faces the second filtration surface 32, creating a second gap 72 between the second surface and the second filtration surface 32. It should be noted that the first gap 71 and the second gap 72 are the gaps between the filter membrane 51 and the embedded core 6. Preferably, all structures in the inner tube 1 are arranged in a centrally symmetrical manner. Furthermore, in membrane separation methods, if the centrifugation time is too long when the filter membrane forms the ultrafiltration centrifuge tube assembly, the local sealing performance requirements for the filter membrane and the ultrafiltration centrifuge tube assembly are higher. Poor sealing will cause leakage, seriously affecting the separation effect and data reliability. This application innovates the structural design of the filter centrifuge tube by adding an embedded core 6, making full use of the membrane area, improving its filtration speed, and shortening the concentration time. The surface of the embedded core 6 is polished to prevent the adsorption of proteins on the material surface. The inner tube includes components such as a central tube, filter sheet, filter membrane, and embedded core. The embedded core is integrally formed with the central tube, or the embedded core and the central tube are detachably connected. It should be noted that the central tube is the main part of the inner tube.

[0034] In a preferred embodiment, the embedded core 6 has a liquid collection groove 13, with the opening of the groove 13 facing the side where the port of the inner tube 1 is located. The first gap 71 and the second gap 72 are respectively connected to the liquid collection groove 13. Preferably, the liquid collection groove 13 extends through the embedded core 6 from top to bottom and is vertically positioned at the center of the embedded core 6. The opening of the liquid collection groove 13 is the liquid collection port. The liquid collection port is pre-reserved on the embedded core and has a certain taper from top to bottom, making it convenient to use a pipette to draw out the concentrate through the liquid collection port after centrifugation.

[0035] In a preferred embodiment, the shape of the liquid collection groove 13 gradually decreases from top to bottom, so that the shape of the liquid collection groove 13 matches the shape of the pipette tip. More preferably, the shape of the liquid collection groove 13 is a conical groove 13 that is larger at the top and smaller at the bottom, which facilitates the use of a pipette to draw out the concentrate through the liquid collection port.

[0036] In a preferred embodiment, the first filter surface 31 and the vertical direction are at an angle, and the second filter surface 32 and the vertical direction are at an angle, and the first filter surface 31 and the second filter surface 32 are mirror images of each other.

[0037] In a preferred embodiment, the included angle ranges from 1 to 10°.

[0038] In a preferred embodiment, the first surface is parallel to the first filter surface 31, and the second surface is parallel to the second filter surface 32. The gap width of the first gap 71 and the second gap 72 is 0.05-1.5 mm. The two sides of the embedded core 6 are parallel to the membrane surface of the filter membrane 51 and maintain a certain distance. The gap width of 0.05-1.5 mm ensures that the liquid can fully contact the membrane surface. A liquid outlet is reserved in the middle of the embedded core 6 to facilitate the insertion of a pipette to remove the concentrate after centrifugation. Optionally, the filter plate has several liquid outlets. Liquid passing through the membrane surface collects in the outlet holes and flows out into the outer tube 8 for collection.

[0039] In a preferred embodiment, the gap width of the first gap 71 and the second gap 72 is 0.1-0.4 mm. This gap width ensures that the liquid can fully contact the membrane surface. More preferably, the height of the upper end of the embedded core 6 is basically flush with or lower than the upper end of the filter membrane, and the height of the upper end of the embedded core 6 is level with or slightly lower than the upper end of the filter membrane 51 by 0-15 mm.

[0040] In a preferred embodiment, the embedded core 6 is integrally formed with the inner tube 1; alternatively, the embedded core 6 is detachably installed inside the filter cavity 4 of the inner tube 1, with the shape and size of the embedded core 6 matching the shape and size of the filter cavity 4, such that the two sides of the embedded core 6 are respectively aligned and fitted into both ends of the filter cavity 4. The shape of the embedded core 6, especially the shape of the two ends of the embedded core 6, is modeled after the inner cavity structure of the inner tube 1, thus reducing the dead volume of the filtration area. The embedded core 6 can be a separate unit; after the inner tube 1 and the embedded core 6 are manufactured separately, the embedded core 6 is placed into the inner tube 1.

[0041] After the central tube 14 is manufactured, the inner core 6 is inserted to form the inner tube 1.

[0042] Then, the assembled inner tube 1 is inserted into the outer tube 8, and the tube cap is screwed on, thus completing the production of a single centrifuge tube.

[0043] Optionally, the material of the inner core 6 is the same as that of the inner tube 1, and the material of the inner tube 1 is any one or more of polystyrene, polystyrene-butadiene copolymer, polystyrene-butadiene-acrylonitrile copolymer, polycarbonate, polypropylene, etc.

[0044] In a preferred embodiment, the inner tube 1 is provided with limiting grooves on both sides of the inner wall of the filter chamber 4. The limiting grooves are arranged in a vertical direction. The two sides of the embedded core 6 are respectively embedded in the limiting grooves. The two sides of the embedded core 6 are interference-fitted with the limiting grooves.

[0045] The centrifuge tube of the present invention has the following advantages: 1. More efficient use of membrane area and faster filtration speed; 2. Shorter centrifugation and filtration time, and better prevention of protein aggregation during centrifugation; 3. Better membrane flow rate and stronger membrane scouring ability, preventing membrane fouling.

[0046] In a preferred embodiment, another aspect provides an ultrafiltration centrifuge tube, including the inner tube 1. The ultrafiltration centrifuge tube is composed of an outer tube, a cap, and an inner tube. The inner tube is composed of a central tube, a filter element, a filter membrane, and an embedded core. An outer tube 8 is fitted over the inner tube 1. A filtrate cavity is formed between the outer wall of the inner tube 1 and the inner wall of the outer tube 8. Caps are provided at the ends of the inner tube 1 and the outer tube 8. The inner tube 1 and the outer tube 8 are concentrically arranged. An air passage notch is provided at the outer edge of the opening of the inner tube 1. A limiting protrusion is provided at the outer edge of the opening of the inner tube 1, and a corresponding limiting groove is provided at the inner edge of the opening of the outer tube 8. When the outer edge of the opening of the inner tube 1 overlaps the inner edge of the opening of the outer tube 8, the limiting protrusion is aligned and overlaps within the limiting groove. An anti-roll protrusion is provided on the outer surface of the cap, and the anti-roll protrusion protrudes above the outer surface of the cap and forms an anti-roll plane. The anti-roll plane is perpendicular to the line connecting the center of the tube cap.

[0047] Preferably, when the embedded core 6 and the central tube 14 are detachably installed, the inner tube 1 includes the central tube 14, the embedded core 66, and the membrane filter 5. The lower end of the central tube has two filter cutouts facing each other. The filter 5 is fixed to the two facing filter cutouts by welding and embedding to form a first filter surface and a second filter surface. The first filter surface and the second filter surface are mirror symmetrical. Both the first filter surface and the second filter surface have filter holes. The inner tube 1 is covered with an outer tube 8. The ports of the inner tube 1 and the outer tube 8 are covered with tube caps. The inner tube 1 has a liquid storage chamber. A gap filtration chamber is formed between the outer wall of the central tube and the inner wall of the outer tube 8. The filter holes connect the liquid storage chamber and the gap filtration chamber. The filter membrane covers the filter holes. In this design, a filter membrane is welded to the inner side of the filter element 53 to form a membrane-coated filter element 5. An annular filter element welding area 12 is located on the outer side of the central tube 14 around the filter perforation. The membrane-coated filter element 5 is embedded in the filter perforation, such that its periphery covers the filter element welding area 12, and the membrane-coated filter element 5 is fixed by welding. A stepped surface is formed around the periphery of the filter element, abutting against the filter element welding area 12. The stepped surface and the filter element welding area 12 are fixed by welding. The welding method includes one of the following: hot melt welding, high-frequency welding, ultrasonic welding, and laser welding. Optionally, the inner tube 1 includes a central tube 14, an embedded core 66, and a membrane filter 5. A filter cutout is provided on the lower left side of the central tube. The membrane filter 5 is fixed in two oppositely arranged filter cutouts by welding to form a first filter surface. A filter 5 is integrally formed on the lower right side of the central tube. The filter membrane is fixed on the inner side of the filter 53 by welding to form a membrane filter 5, which forms a second filter surface. The first filter surface and the second filter surface are arranged opposite to each other and are mirror-symmetrical.

[0048] Optionally, when the embedded core 6 and the central tube 14 are integrally formed, the manufacturing of the ultrafiltration centrifuge tube includes the following steps: manufacturing an integrally formed central tube and filter sheet, such that the shape and size of the filter sheet match the filter cutout; covering the inner side of the filter sheet with a filter membrane and fixing it by welding to obtain a membrane-coated filter sheet 5; embedding the membrane-coated filter sheet 5 into the filter cutout, such that the periphery of the membrane-coated filter sheet 5 covers the filter sheet welding area 12, and fixing the membrane-coated filter sheet 5 by welding to manufacture the inner tube 1 of the ultrafiltration centrifuge tube;

[0049] The inner tube 1 is subjected to an airtightness test. If the airtightness is qualified, it is assembled with the outer tube 8 and the tube cap to obtain an ultrafiltration centrifuge tube.

[0050] In order to gain a better understanding of the technical solution of the present invention, several embodiments and comparative examples are listed below for further detailed description.

[0051] Example 1

[0052] The ultrafiltration centrifuge tube consists of an outer tube, a cap, and an inner tube. The inner tube comprises a central tube, a filter element, a filter membrane, and an embedded core. After the above components of the centrifuge tube are injection molded using a polystyrene injection molding machine, the pre-cut filter membrane with a molecular weight cutoff of 30 kDa is fixed to the filter element by hot-melt welding to obtain a membrane-coated filter element. The membrane-coated filter element is then welded to the welding positions on both sides of the central tube. The embedded core is embedded in the center of the inner tube, resulting in an inner tube with a gap width of 0.3 mm for both the first and second gaps. The airtightness of the inner tube is tested. After the airtightness is qualified, the outer tube and the cap are fitted onto the inner tube to assemble the ultrafiltration centrifuge tube sample.

[0053] Example 2

[0054] Compared with Example 1, the filter membrane used in Example 2 has a molecular rejection rate of 10kD, and the rest of the structure and manufacturing method are exactly the same as in Example 1. The ultrafiltration centrifuge tube sample was then assembled.

[0055] Comparative Example 1

[0056] Compared with Example 1, the inner tube used in Comparative Example 1 did not have an embedded core installed, but the rest of the structure and manufacturing method were exactly the same as in Example 1, and an ultrafiltration centrifuge tube sample was assembled.

[0057] Comparative Example 2

[0058] Compared with Example 2, the inner tube used in Comparative Example 2 did not have an embedded core installed, but the rest of the structure and manufacturing method were the same as in Example 2, and an ultrafiltration centrifuge tube sample was assembled.

[0059] The filtration rate of the assembled ultrafiltration centrifuge tubes from Examples 1-2 and Comparative Examples 1-2 was compared in a filtration rate test experiment.

[0060] Take the same number of ultrafiltration centrifuge tubes from the ultrafiltration centrifuge tube samples for testing. Add the filtrate to the inner tube and centrifuge using a fixed-angle rotor centrifuge. Concentrate the filtrate with the same centrifugal force and for the same centrifugation time. Record the weight of the liquid filtered out of the outer tube by weighing. Calculate the concentration factor based on the recorded weight. After centrifugation, test and record the protein concentration of the concentrated liquid in the inner tube.

[0061] The specific method for weighing the liquid weight of the filtrate in the outer tube after each centrifugation is as follows: Weigh and record the weight N of the empty outer tube before centrifugation. Fill the inner tube of the assembled centrifuge tube with the filtrate and centrifuge using a fixed-angle rotor centrifuge. After each centrifugation, remove the outer tube and weigh it to obtain the total weight M of the outer tube and the filtrate in the outer tube. Record the weight M. Subtract the weight N of the outer tube from the total weight M to obtain the liquid weight Q of the filtrate in the outer tube, where Q = MN.

[0062] The conditions for the filtration rate test of the ultrafiltration centrifuge tube samples in Examples 1-2 and Comparative Examples 1-2 are shown in Table 1:

[0063] Table 1

[0064]

[0065] 1. Filtration speed test comparison experiment one:

[0066] Centrifuge tube samples assembled using filter membranes with a molecular rejection rate of 30 kDa from both Example 1 and Comparative Example 1 were compared and tested using BSA solution as the filtrate.

[0067] Four ultrafiltration centrifuge tubes were taken from the ultrafiltration centrifuge tube samples in Example 1 as the experimental group, and four ultrafiltration centrifuge tubes were taken from the ultrafiltration centrifuge tube samples in Comparative Example 1 as the control group. 10 mL of 1000 mg / L BSA solution was added to the inner tubes of both the experimental and control groups. Centrifugation was performed using a fixed-angle rotor centrifuge at a centrifugal force of 5000 g for 2 minutes each time, for a total of four cycles. The weight of the filtrate in the outer tube was recorded after each centrifugation. After centrifugation, the protein concentration of the concentrate in the inner tube was recorded. Specific results are shown in Tables 2-5.

[0068] (1) Results of the experimental group

[0069] The test data of the four ultrafiltration centrifuge tubes in the experimental group are shown in Table 2 below:

[0070] Table 2

[0071]

[0072] Based on the data recorded in the table above, the concentration factors were calculated as follows. The concentrations and concentration factors of the four centrifuge tubes in the experimental group after centrifugation for 8 minutes are shown in Table 3 below:

[0073] Table 3

[0074]

[0075] (2) Results of the control group

[0076] The test data of the four ultrafiltration centrifuge tubes in the control group are shown in Table 4 below:

[0077] Table 4

[0078]

[0079] Based on the data recorded in the table above, the following concentration ratios were calculated. The concentrations and concentration ratios of the four centrifuge tubes in the control group after centrifugation for 8 minutes are shown in Table 5 below:

[0080] Table 5

[0081]

[0082] As shown in Table 2, after filtration for 8 minutes using the ultrafiltration tube sample from Example 1, the cumulative weight of the filtrate was 9.768-9.809 g, with a remaining volume of approximately 200-240 μL. As shown in Table 3, the ultrafiltration tube sample from Example 1 achieved a concentration factor of 42.18-51.12 times after filtration for 8 minutes, with an average concentration of 46.65 times.

[0083] As shown in Table 4, after filtration for 8 minutes, the cumulative weight of the filtered liquid in the control group of Comparative Example 2 was 9.285-9.313 g, and the remaining volume of concentrated liquid in the central tube was 680-710 μL, which is approximately three times that of the present invention. As shown in Table 5, the concentration factor of the control group of Comparative Example 2 was 13.43-14.24 times, with an average concentration of 13.74 times.

[0084] In summary, compared to the control group ultrafiltration tube sample from Example 1, the concentration factor was significantly higher after filtration for the same 8 minutes. The results indicate that when using filter membranes with a molecular cutoff of 30 kDa, the use of an embedded core greatly improves the filtration rate of the ultrafiltration tube.

[0085] 2. Comparison Experiment Two: Filtration Speed ​​Test

[0086] Ultrafiltration centrifuge tube samples were assembled using filter membranes with a molecular rejection rate of 10 kDa from both Example 2 and Comparative Example 2. A comparative experiment was conducted to test the filtration rate using cytochrome C concentration.

[0087] Four ultrafiltration centrifuge tubes were taken from the ultrafiltration centrifuge tube samples in Example 2 as the experimental group, and four ultrafiltration centrifuge tubes were taken from the ultrafiltration centrifuge tube samples in Comparative Example 2 as the control group. 10 mL of 250 mg / L cytochrome C solution was added to the inner tube, and centrifugation was carried out using a fixed-angle rotor centrifuge at a centrifugal force of 5000 g for 2-5 min each time. After each centrifugation, the outer tube was removed, and the weight of the filtrate in the outer tube was weighed and recorded. The concentration of cytochrome C in the concentrated solution in the inner tube after centrifugation was measured. The specific results are shown in Tables 6-9.

[0088] (1) Results of the experimental group.

[0089] The test data of the four ultrafiltration centrifuge tube samples in the experimental group are shown in Table 6 below:

[0090] Table 6

[0091]

[0092] Based on the data recorded in the table above, the concentration factor was calculated. The protein concentrations of the four centrifuge tubes in the experimental group after centrifugation for 19 minutes are shown in Table 7 below.

[0093] Table 7

[0094]

[0095] (2) Results of the control group

[0096] The test data of the four ultrafiltration centrifuge tubes in the control group are shown in Table 8 below:

[0097] Table 8

[0098]

[0099] Based on the data recorded in the table above, the concentration factor was calculated. The protein concentrations of the four centrifuge tubes in the experimental group after centrifugation for 19 minutes are shown in Table 9 below:

[0100] Table 9

[0101]

[0102] As shown in Tables 6 and 7, after filtration for 19 minutes, the cumulative weight of the filtered liquid in the ultrafiltration tube sample of Example 2 was 9.442-9.521 g, and the volume of the remaining concentrated liquid in the central tube was 480-560 μL; the concentration factor after 19 minutes of filtration was 16.7-19.56 times, with an average concentration of 18.43 times.

[0103] As shown in Tables 8 and 9, after filtration for 19 minutes, the cumulative weight of the filtered liquid in the ultrafiltration tube of Comparative Example 2 was 9.036-9.059 g, and the volume of the remaining concentrated liquid in the central tube was 940-970 μL. The concentration factor reached 9.70-9.99 times after filtration for 19 minutes, with an average concentration of 9.88 times.

[0104] As can be seen, in comparison, with the same filtration time of 19 min, the concentration factor of the ultrafiltration tube sample in Example 2 was 18.43 times, which is much higher than the average concentration factor of 9.88 times in Control Example 2. The results show that when using filter membranes with a molecular cutoff of 10 kDa, the filtration rate of the ultrafiltration tube is greatly improved by using an embedded core.

[0105] This demonstrates that the inner tube structure of the present invention is reasonable. Due to the more efficient use of membrane area in Examples 1-2, the ultrafiltration tube with an embedded core in the inner tube has a faster filtration speed. The centrifugation speed of the ultrafiltration tube with an embedded core in the inner tube of the present invention is greatly improved.

[0106] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0107] In the description of this specification, the references to terms such as "preferred embodiment," "another embodiment," "other embodiment," or "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0108] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An inner tube for ultrafiltration, characterized in that, The device includes a cylindrical portion, a filter portion at the lower end of the cylindrical portion, a filter cavity, a first filter surface and a second filter surface disposed opposite each other on the sides of the filter portion, a filter membrane disposed on the first filter surface and the second filter surface, an embedded core disposed in the filter cavity, the embedded core being located between the first filter surface and the second filter surface, the front side of the embedded core having a first surface, the back side of the embedded core having a second surface, the first surface being directly opposite the first filter surface such that there is a first gap between the first surface and the first filter surface, and the second surface being directly opposite the second filter surface such that there is a second gap between the second surface and the second filter surface; The embedded core is provided with a liquid extraction groove, the opening of which faces the side where the port of the inner tube is located, and the first gap and the second gap are respectively connected to the liquid extraction groove; The gap width of the first gap and the second gap is 0.05-1.5mm.

2. The inner tube as described in claim 1, characterized in that, The shape of the liquid collection tank gradually decreases from top to bottom, so that the shape of the liquid collection tank matches the shape of the pipette tip.

3. The inner tube as described in claim 2, characterized in that, The first filter surface and the vertical direction are at an angle, and the second filter surface and the vertical direction are at an angle, and the first filter surface and the second filter surface are mirror images of each other.

4. The inner tube as described in claim 3, characterized in that, The included angle ranges from 1 to 10°.

5. The inner tube as described in claim 1, characterized in that, The first surface is parallel to the first filter surface, and the second surface is parallel to the second filter surface.

6. The inner tube as described in claim 5, characterized in that, The gap width of the first gap and the second gap is 0.1-0.4 mm.

7. The inner tube as described in claim 1, characterized in that, The embedded core is detachably installed inside the inner tube. The shape and size of the embedded core match the shape and size of the filter cavity, so that the two sides of the embedded core are respectively aligned and fitted into the two ends of the filter cavity.

8. The inner tube as described in claim 7, characterized in that, The inner wall of the inner tube has two opposing limiting grooves on its inner side. The limiting grooves are arranged in a vertical direction. The two sides of the inner core are respectively embedded in the limiting grooves. The two sides of the inner core are interference-fitted with the limiting grooves.

9. An ultrafiltration centrifuge tube, characterized in that, The device includes an inner tube as described in any one of claims 1-8, an outer tube sleeved around the inner tube, a filter fluid cavity formed between the outer wall of the inner tube and the inner wall of the outer tube, and a cap covering the ports of the inner tube and the outer tube, wherein the inner tube and the outer tube are concentrically arranged.

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