Ultrafiltration centrifuge tube and inner tube thereof

Abstract

The invention provides an ultrafiltration tube and an inner tube thereof, the inner tube comprises a cylindrical part, the lower end of the cylindrical part is provided with a filtering part, the filtering part is provided with a filtering cavity, the side surface of the filtering part is oppositely provided with a first filtering surface and a second filtering surface, the first filtering surface and the second filtering surface are provided with filtering membranes, and an embedded core is arranged in the filtering cavity. The embedded core is located between the first filtering face and the second filtering face, the front face of the embedded core is provided with a first surface, the back face of the embedded core is provided with a second surface, the first surface is right opposite to the first filtering face, so that a first gap is formed between the first surface and the first filtering face, and the second surface is right opposite to the second filtering face. And a second gap is formed between the second surface and the second filtering surface.

Description

Technical Field

[0001] The present invention relates to the field of centrifuge tubes, and particularly to an ultrafiltration centrifuge tube and an inner tube thereof. Background Art

[0002] In the field of life sciences, membrane separation has become an efficient separation method, gradually replacing traditional separation methods such as chemical precipitation, dialysis, and lyophilization. Among them, ultrafiltration centrifuge tubes are commonly used membrane separation tools in laboratories, mainly used for the concentration, desalting, buffer replacement, or separation and purification of biological macromolecules, etc.; ultrafiltration centrifuge tubes drive the solution through the filter membrane by centrifugal force according to the pore size of the filter membrane for selective retention. In this way, macromolecules such as proteins are retained by the filter membrane in the upper layer to form a retention solution, while small molecules such as salts and water are filtered out to the lower layer by the ultrafiltration membrane to obtain a filtrate. When 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 centrifugation time are set. After centrifugation, the upper layer of the ultrafiltration centrifuge tube is a retention solution concentrated with the target macromolecule, and the lower layer of the ultrafiltration centrifuge tube is a filtrate composed of filtered small molecules and solvents.

[0003] Ultrafiltration centrifuge tubes are classified into two categories according to the placement method of the filter membrane in the main structure. One category is that the filter membrane is horizontally placed, and the other category is that the filter membrane is vertically placed in the centrifuge tube; due to the limitation of the structure of the horizontally placed filter membrane, the membrane area is usually small, and it is easy to form concentration polarization, resulting in an increasingly slow filtration speed and affecting the filtration efficiency. Therefore, most of the filter membranes of ultrafiltration centrifuge tubes on the market are placed in an approximately vertical manner. The centrifuge tubes with the filter membrane vertically placed have a larger membrane area, can reduce the membrane pollution caused by concentration polarization, and the filtration speed is also faster than the former.

[0004] However, there are also corresponding defects in the vertical placement of the filter membrane: during centrifugation, as the upper-layer feed liquid is gradually concentrated and reduced, when the feed liquid is reduced to a certain extent due to the continuous filtration of small molecules and solvents to the lower layer, the upper membrane surface of the centrifuge tube begins to be not fully wetted by the remaining feed liquid and is exposed. In this way, the wetted membrane surface by the remaining feed liquid becomes smaller, resulting in a gradual reduction of the filtration area and a decrease in the filtration speed. The filtration speed is slow in the later stage, leading to a long overall filtration time and also causing membrane pollution due to concentration polarization.

[0005] In the prior art, although some ultrafiltration centrifuge tubes with improved new structures have emerged to improve these defects of the vertical filter membrane. For example, the new-type patent CN205253154U discloses an ultrafiltration centrifuge tube, which includes a sample receiving cavity, a filter plate, a filter membrane, a tube cap, and a filtration recovery tube. Among them, the sample receiving cavity includes an upper cavity and a lower cavity. The upper cavity forms a sample storage cavity, and a sample inlet opening is provided on the upper end surface of the upper cavity; the lower cavity includes a dead-end body and an outer frame wall. The outer frame wall forms a filtration cavity, and the dead-end body is arranged at the bottom of the outer frame wall to prevent sample loss to dryness during the centrifugal filtration process; 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 diversion channel is arranged on the upper surface of the filter membrane support block, and a plurality of liquid discharge holes are arranged at the lower end of the diversion channel. Although this existing patent has improved the filtration area and filtration efficiency to a certain extent, however, these patents on the market have very limited improvement in the filtration speed, the overall filtration time is still very long, and the problem of membrane pollution caused by concentration polarization cannot be solved either. Summary of the Invention

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

[0007] To solve the above technical problems, the present invention provides an inner tube of an ultrafiltration tube, which includes a cylindrical part. A filtration part is arranged at the lower end of the cylindrical part. The filtration part has a filtration cavity. A first filtration surface and a second filtration surface are oppositely arranged on the side surface of the filtration part. Filter membranes are arranged at the first filtration surface and the second filtration surface. An embedded core is arranged in the filtration cavity. The embedded core is located between the first filtration surface and the second filtration surface. The front surface of the embedded core has a first surface, and the back surface of the embedded core has a second surface. The first surface faces the first filtration surface directly, so that there is a first gap between the first surface and the first filtration surface. The second surface faces the second filtration surface directly, so that there is a second gap between the second surface and the second filtration surface.

[0008] Preferably, a liquid extraction groove is formed on the embedded core. The notch of the liquid extraction groove faces the side where the port of the inner tube is located. The first gap and the second gap communicate with the liquid extraction groove respectively.

[0009] Preferably, the shape of the liquid extraction groove gradually becomes smaller from top to bottom, so that the shape of the liquid extraction groove matches the shape of the pipette tip.

[0010] Preferably, an included angle exists between the first filtration surface and the vertical direction, and an included angle exists between the second filtration surface and the vertical direction. The first filtration surface and the second filtration surface are mirror-symmetrical.

[0011] Preferably, the embedded core and the inner tube are integrally formed, and the value range of the included angle is 1-10°.

[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 widths of the first gap and the second gap are 0.05 - 1.5 mm.

[0013] Preferably, the gap widths of the first gap and the second gap are 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 both sides of the embedded core are respectively positioned and clamped at both ends of the filter cavity.

[0015] Preferably, on both sides of the inner wall of the inner tube, there are relatively arranged limiting grooves which are arranged in the vertical direction. Both sides of the embedded core are respectively embedded in the limiting grooves, and both sides of the embedded core are in interference fit with the limiting grooves.

[0016] On the other hand, there is also provided an ultrafiltration centrifuge tube, including the inner tube. An outer tube is sleeved outside the inner tube. A filtrate cavity is formed between the outer wall of the inner tube and the inner wall of the outer tube. Tube caps are provided at the ports of the inner tube and the outer tube, and the inner tube and the outer tube are concentrically arranged.

[0017] Advantages of the present invention: By improving the structure of the inner tube, increasing the liquid disturbance on the membrane surface and enhancing the membrane surface turbulence, the present invention greatly improves the utilization of the membrane area during the concentration process, reduces membrane fouling, increases the filtration rate, and shortens the separation and concentration time. Description of the Drawings

[0018] Specifically illustrated by the preferred embodiments of the present invention shown in the drawings, the above and other objects, features and advantages of the present invention will become clearer. The same reference numerals in all the drawings indicate the same parts, and the drawings are not deliberately drawn to scale in actual size, with the emphasis on showing the gist of the present invention.

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

[0020] Figure 2 It is a front view of the central tube with an embedded core in the first embodiment of the present invention;

[0021] Figure 3 It is Figure 2 a sectional view of the central tube at A - A in

[0022] Figure 4 It is Figure 2 a sectional view of the central tube at F - F in

[0023] Figure 5 Side view of the central tube with an embedded core in the first embodiment of the present invention;

[0024] Figure 6 is Figure 5 Cross-sectional view taken at B-B in;

[0025] Figure 7 Top view of the central tube of the first embodiment of the present invention;

[0026] Figure 8 Cross-sectional view of the inner tube of the first embodiment of the present invention;

[0027] Figure 9 Stereogram of the inner tube of the first embodiment of the present invention;

[0028] Figure 10 Schematic diagram of the front view of the outer tube of the first embodiment of the present invention;

[0029] In the figure: inner tube 1; cylindrical part 2; filtering part 3; first filtering surface 31; second filtering surface 32; filtering cavity 4; film-covered filtering sheet 5; filter membrane 51; filtering sheet 53; embedded core 6; first gap 71; second gap 72; outer tube 8; filtering sheet welding position 12; liquid extraction groove 13; central tube 14. Detailed implementation manners

[0030] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings.

[0031] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element and integrated with it, or there may be an intermediate element. The terms "installed", "one end", "the other end" and similar expressions used herein are only for the purpose of illustration.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this technology belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0033] Reference Figures 1-10, the present invention provides an inner tube 1 of an ultrafiltration tube, which includes a cylindrical part 2. A filtering part 3 is arranged at the lower end of the cylindrical part 2. A filtering cavity 4 is formed inside the filtering part 3. A first filtering surface 31 and a second filtering surface 32 are oppositely arranged on the side surface of the filtering part 3. Filter membranes 51 are arranged at the first filtering surface 31 and the second filtering surface 32. An embedded core 6 is arranged in the filtering cavity 4. The embedded core 6 is located between the first filtering surface 31 and the second filtering surface 32. The front surface of the embedded core 6 has a first surface, and the back surface of the embedded core has a second surface. The first surface faces the first filtering surface 31, so that there is a first gap 71 between the first surface and the first filtering surface 31. The second surface faces the second filtering surface 32, so that there is a second gap 72 between the second surface and the second filtering surface 32. It should be noted that the first gap 71 and the second gap 72 are the voids between the filter membrane 51 and the embedded core 6. Preferably, all the structures in the inner tube 1 are centrosymmetrically arranged. Moreover, in the membrane separation method, when forming an ultrafiltration centrifuge tube assembly, if the centrifugation time is too long, higher requirements are imposed on the local sealing performance between the filter membrane and the ultrafiltration centrifuge tube assembly. Poor sealing will cause leakage, seriously affecting the separation effect and data credibility. In this application, the structure design of the filtering centrifuge tube is innovated by adding the embedded core 6, making full use of the membrane area, improving its filtering 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, a filtering sheet, a filter membrane, and an embedded core. The embedded core is integrally formed with the central tube, or the embedded core is detachably connected to the central tube. It should be noted that the central tube is the main part of the inner tube.

[0034] In a preferred embodiment, a liquid extraction groove 13 is formed on the embedded core 6. The notch of the liquid extraction groove 13 faces the side where the port of the inner tube 1 is located. The first gap 71 and the second gap 72 communicate with the liquid extraction groove 13 respectively. Preferably, the liquid extraction groove 13 penetrates the embedded core 6 from top to bottom, and the liquid extraction groove 13 is vertically arranged at the center of the embedded core 6. The notch of the liquid extraction groove 13 is the liquid extraction port. A liquid extraction port is reserved on the embedded core, and the liquid extraction port has a certain taper from top to bottom. After centrifugation, it is convenient to suck out the concentrated solution through the liquid extraction port with a pipette.

[0035] In a preferred embodiment, the shape of the liquid extraction groove 13 gradually becomes smaller from top to bottom, so that the shape of the liquid extraction groove 13 matches the shape of the pipette tip. Preferably, the shape of the liquid extraction groove is a tapered groove 13 that is larger at the top and smaller at the bottom, which is convenient to suck out the concentrated solution through the liquid extraction port with a pipette.

[0036] In a preferred embodiment, an angle is formed between the first filter surface 31 and the vertical direction, and an angle is formed between the second filter surface 32 and the vertical direction, and the first filter surface 31 and the second filter surface 32 are mirror-symmetrical.

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

[0038] In a preferred embodiment, the first surface is parallel to the first filter surface 31, the second surface is parallel to the second filter surface 32, and the gap width of the first gap 71 and the second gap 72 is 0.05-1.5 mm. The two side surfaces of the embedded core 6 are respectively 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 collection port is reserved in the middle of the embedded core 6, so that after the centrifugation is completed, a pipette can be inserted from this position to take out the concentrated liquid. Optionally, the filter plate is provided with a plurality of liquid outflow ports, and the liquid that passes through the membrane surface is collected in the outflow hole, flows out from the outflow port into the outer tube 8, and is collected.

[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. Preferably, the height of the upper end of the embedded core 6 is substantially flush with the upper end of the filter membrane or lower than the membrane surface, and the height of the upper end of the embedded core 6 is flush with the upper end of the filter membrane surface, or slightly lower than 0-15 mm above the filter membrane 51.

[0040] In a preferred embodiment, the embedded core 6 is integrally formed with the inner tube 1; or, the embedded core 6 is detachably installed inside the filter cavity 4 of the inner tube 1, and the shape and size of the embedded core 6 match the shape and size of the filter cavity 4, so that the two side edges of the embedded core 6 are respectively aligned and embedded in the two ends of the filter cavity 4, and the shape of the embedded core 6, especially the shape of the two side ends of the embedded core 6, is contoured according to the inner cavity structure of the inner tube 1, and the embedded core 6 reduces the dead volume of the filtration area. The embedded core 6 can be a split type, and the embedded core 6 is placed in the inner tube 1 after the inner tube 1 and the embedded core 6 are respectively manufactured.

[0041] After the central tube 14 is manufactured, the embedded core 6 is placed in it to form the inner tube 1.

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

[0043] Optionally, the material of the embedded 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, and the like.

[0044] In a preferred embodiment, on both sides of the inner wall of the filtration chamber 4, there are relatively arranged limiting grooves for the inner tube 1. The limiting grooves are arranged in the vertical direction. The two side edges of the embedded core 6 are respectively embedded in the limiting grooves, and the two side edges of the embedded core 6 are in interference fit with the limiting grooves.

[0045] The centrifuge tube of the present invention has the following advantages: 1. The membrane area is utilized more fully and the filtration speed is faster; 2. The centrifugal filtration time is shortened, and the agglomeration of proteins during centrifugation is better prevented; 3. The flow velocity on the membrane surface is better, the scouring ability on the membrane surface is stronger, and membrane fouling is prevented.

[0046] In a preferred embodiment, on the other hand, an ultrafiltration centrifuge tube is also provided, which includes the inner tube 1. The ultrafiltration centrifuge tube is composed of an outer tube, a tube cap, and an inner tube. Among them, the inner tube is composed of a central tube, a filter sheet, a filter membrane, and an embedded core. An outer tube 8 is sleeved outside the inner tube 1. A filtrate chamber is formed between the outer wall of the inner tube 1 and the inner wall of the outer tube 8. Tube caps are provided at the ports of the inner tube 1 and the outer tube 8. The inner tube 1 and the outer tube 8 are concentrically arranged. An air passing notch is provided at the outer edge of the tube orifice of the inner tube 1. A limiting protrusion is provided at the outer edge of the tube orifice of the inner tube 1, and a limiting groove is correspondingly provided at the inner edge of the tube orifice of the outer tube 8. When the outer edge of the tube orifice of the inner tube 1 is placed on the inner edge of the tube orifice of the outer tube 8, the limiting protrusion is placed in the limiting groove in an aligned manner. An anti-rolling boss is provided on the outer surface of the tube cap. The anti-rolling boss protrudes above the outer surface of the tube cap and forms an anti-rolling plane. The connection line between the anti-rolling plane and the center of the tube cap is perpendicular.

[0047] Preferably, when the embedded core 6 is detachably installed with the central tube 14, the inner tube 1 includes a central tube 14, an embedded core 66, and a film-covered filter sheet 5. Two filter cutouts are oppositely provided at the lower end of the central tube. The filter sheet is fixedly embedded by welding respectively in the two oppositely arranged filter cutouts 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. An outer tube 8 is sleeved outside the inner tube 1. The ports of the inner tube 1 and the outer tube 8 are covered with tube caps. A liquid storage cavity is formed inside the inner tube 1. A gap filtration cavity is formed between the outer wall of the central tube and the inner wall of the outer tube 8. The filter holes communicate the liquid storage cavity and the gap filtration cavity, and a filter membrane covers the filter holes. Among them, a filter membrane is fixedly welded to the inner side of the filter sheet 53 to form a film-covered filter sheet 5. An annular filter sheet welding area 12 is provided along the periphery of the filter cutout on the outside of the central tube 14. The film-covered filter sheet 5 is embedded at the filter cutout so that the periphery of the film-covered filter sheet covers the filter sheet welding area 12, and the film-covered filter sheet 5 is fixed by welding. A stepped surface is formed on the periphery of the filter sheet, and the stepped surface abuts against the filter sheet welding area and is fixed to the filter sheet welding area 12 by welding. The welding method includes one of 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 film-covered filter sheet 5. A filter cutout is provided on the left side at the lower end of the central tube. The film-covered filter sheet 5 is fixedly embedded by welding respectively in the two oppositely arranged filter cutouts to form a first filter surface. A filter sheet 5 is integrally formed on the right side at the lower end of the central tube. A filter membrane is fixedly welded to the inner side of the filter sheet 53 to form a film-covered filter sheet 5, forming a second filter surface. The first filter surface and the second filter surface are oppositely arranged, and the first filter surface and the second filter surface are mirror-symmetrical.

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

[0049] Performing an airtightness test on the above-mentioned inner tube 1. If the airtightness is qualified, assembling it with the outer tube 8 and the tube cap to obtain an ultrafiltration centrifuge tube.

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

[0051] Embodiment 1

[0052] The ultrafiltration centrifuge tube is composed of an outer tube, a tube cap, and an inner tube. Among them, the inner tube is composed of a central tube, a filter sheet, a filter membrane, and an embedded core. After using polystyrene to injection mold the above components of the centrifuge tube with an injection molding machine, a filter membrane with a molecular cut-off rate of 30 kD cut to size is fixed to the filter sheet by hot melt welding to obtain a film-coated filter sheet. The film-coated filter sheet is successively welded to the welding positions on both sides of the central tube. The embedded core is embedded in the central position of the inner tube to obtain an inner tube with the gap widths of the first gap and the second gap both being 0.3 mm after assembly. The air tightness of the inner tube is tested. After the air tightness is qualified, the inner tube is sleeved with the outer tube and the tube cap to assemble an ultrafiltration centrifuge tube sample.

[0053] Embodiment 2

[0054] Compared with Embodiment 1, the molecular cut-off rate of the filter membrane used in Embodiment 2 is 10 kD, and the remaining structures and manufacturing methods are exactly the same as those in Embodiment 1, and an ultrafiltration centrifuge tube sample is assembled.

[0055] Comparative Example 1

[0056] Compared with Embodiment 1, the inner tube used in Comparative Example 1 is not installed with an embedded core, and the remaining structures and manufacturing methods are exactly the same as those in Embodiment 1, and an ultrafiltration centrifuge tube sample is assembled.

[0057] Comparative Example 2

[0058] Compared with Embodiment 2, the inner tube used in Comparative Example 2 is not installed with an embedded core, and the remaining structures and manufacturing methods are the same as those in Embodiment 2, and an ultrafiltration centrifuge tube sample is assembled.

[0059] A filtration speed test and comparison experiment is carried out on the assembled ultrafiltration centrifuge tubes of Embodiments 1-2 and Comparative Examples 1-2:

[0060] Take the same number of ultrafiltration centrifuge tubes from the ultrafiltration centrifuge tube samples for testing. Add the filtration liquid into the inner tube, and use a fixed-angle rotor centrifuge to centrifuge. Concentrate the filtration liquid at the same centrifugal force for the same centrifugal time. The weight of the liquid filtered out in the outer tube is obtained by weighing and recorded. The concentration multiple is calculated according to the recorded weight, and the protein concentration of the concentrated liquid in the inner tube is tested and recorded after the centrifugation ends.

[0061] Among them, after each centrifugation, the specific method for weighing the liquid weight of the filtrate in the outer tube is as follows: Weigh and record the weight N of the empty outer tube before centrifugation. Install the filtration liquid in the inner tube of the assembled centrifuge tube, and centrifuge it using a fixed-angle rotor centrifuge. After each centrifugation, take out the outer tube, weigh to obtain the total weight M of the outer tube and the filtrate in the outer tube, and record it. 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, and Q = M - N.

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

[0063] Table 1

[0064]

[0065] 1. Filtration rate test comparison experiment 1:

[0066] A filtration rate test comparison experiment was carried out using the centrifuge tube samples assembled with the filter membranes with a molecular cut-off rate of 30 kD in Example 1 and Comparative Example 1, and using the BSA solution as the filtration liquid:

[0067] Four ultrafiltration centrifuge tube samples from Example 1 were taken as the experimental group, and four ultrafiltration centrifuge tube samples from Comparative Example 1 were taken as the control group. 10 mL of 1000 mg / L BSA solution was added to the inner tubes of the ultrafiltration centrifuge tube samples in the experimental group and the control group respectively, and centrifuged using a fixed-angle rotor centrifuge with a centrifugal force of 5000 g for 2 minutes each time, for a total of 4 cycles. After each centrifugation, record the weight of the filtrate in the outer tube; after centrifugation, record the protein concentration of the concentrated solution in the inner tube. The specific results are shown in Tables 2-5.

[0068] (1) Results of the experimental group

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

[0070] Table 2

[0071]

[0072] The following concentration multiples were calculated based on the data recorded in the above table. The concentrations and concentration multiples 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 tube samples in the control group are shown in Table 4 below:

[0077] Table 4

[0078]

[0079] The following concentration multiples are calculated based on the data recorded in the above table. The concentrations and concentration multiples of the 4 centrifuge tubes in the control group after centrifugation for 8 minutes are as shown in Table 5 below:

[0080] Table 5

[0081]

[0082] As can be seen from the results shown in Table 2, after filtering with the ultrafiltration tube sample of Example 1 for 8 minutes, the cumulative weight of the filtrate is 9.768 - 9.809 g, and the remaining amount is about 200 - 240 μL. As can be seen from the results shown in Table 3, the concentration multiple of the ultrafiltration tube sample of Example 1 after filtering for 8 minutes reaches 42.18 - 51.12 times, with an average concentration of 46.65 times.

[0083] As can be seen from the results shown in Table 4, after the control group of Comparative Example 2 is filtered for 8 minutes, the cumulative weight of the filtered liquid is 9.285 - 9.313 g, the volume of the concentrated liquid remaining in the central tube is 680 - 710 μL, and the remaining amount is about 3 times that of the present invention. As can be seen from the results shown in Table 5, the concentration multiple of the control group of Comparative Example 2 is 13.43 - 14.24 times, with an average concentration of 13.74 times.

[0084] In summary, it can be seen that, in contrast, with the same 8 - minute filtration, the concentration multiple of the ultrafiltration tube sample of Example 1 is much higher than that of the ultrafiltration tube sample of the control group sampled in Comparative Example 2. The results show that when using a filter membrane with a molecular retention rate of 30 kD, after using the embedded core, the filtration speed of the ultrafiltration tube has been greatly improved.

[0085] 2. Filtration speed test comparison experiment two:

[0086] Ultrafiltration centrifuge tube samples assembled with filter membranes having a molecular retention rate of 10 kD of Example 2 and Comparative Example 2 were used to conduct a filtration speed test comparison experiment with cytochrome C concentration:

[0087] Four were taken from the ultrafiltration centrifuge tube samples in Example 2 as the experimental group, and four 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 with a centrifugal force of 5000 g for 2 - 5 minutes each time. After each centrifugation, the outer tube was taken out, weighed, and the weight of the filtrate in the outer tube was recorded; the cytochrome C concentration of the concentrated liquid 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 4 ultrafiltration centrifugal tube samples in the experimental group are shown in Table 6 below:

[0090] Table 6

[0091]

[0092] Calculate the concentration multiple based on the data recorded in the above table. The protein concentrations of the 4 centrifuge tube samples in the experimental group after centrifugation for 19 min are shown in Table 7 below:

[0093] Table 7

[0094]

[0095] (2) Results of the control group

[0096] The test data of 4 ultrafiltration centrifugal tube samples in the control group are shown in Table 8 below:

[0097] Table 8

[0098]

[0099] Calculate the concentration multiple based on the data recorded in the above table. The protein concentrations of the 4 centrifuge tube samples in the experimental group after centrifugation for 19 min are shown in Table 9 below:

[0100] Table 9

[0101]

[0102] It can be seen from the results shown in Table 6 and Table 7 that after the ultrafiltration tube sample of Example 2 was filtered for 19 minutes, the cumulative filtered liquid weight was 9.442 - 9.521 g, and the remaining concentrated liquid volume in the central tube was 480 - 560 μL; the concentration multiple reached 16.7 - 19.56 times after filtering for 19 min, with an average concentration of 18.43 times.

[0103] It can be seen from the results shown in Table 8 and Table 9 that after the ultrafiltration tube sample of Comparative Example 2 was filtered for 19 minutes, the cumulative filtered liquid weight was 9.036 - 9.059 g, and the remaining concentrated liquid volume in the central tube was 940 - 970 μL; the concentration multiple reached 9.70 - 9.99 times after filtering for 19 min, with an average concentration of 9.88 times.

[0104] It can be seen that, in contrast, with the same filtration time of 19 min, the concentration multiple of the ultrafiltration tube sample of Example 2 was 18.43 times, which was much higher than the average concentration multiple of 9.88 times in Comparative Example 2. The results show that when using a filter membrane with a molecular retention rate of 10 kD, the filtration speed of the ultrafiltration tube has been greatly improved after using the embedded core.

[0105] It shows that the inner tube structure of the present invention is reasonable. Since the membrane area in Embodiments 1-2 is utilized more fully, the ultrafiltration tube with an embedded core in the inner tube has a faster filtration speed, and the centrifugation speed of the ultrafiltration tube with the inner tube provided with an embedded core according to the present invention has been greatly improved.

[0106] In this application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0107] In the description of this specification, the description with reference to terms such as "preferred embodiment", "another embodiment", "other embodiments" or "specific examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0108] Although the embodiments of this application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting this application. Those of ordinary skill 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 of an ultrafiltration tube, characterized in that, It includes a cylindrical part. A filtering part is arranged at the lower end of the cylindrical part. The filtering part has a filtering cavity. A first filtering surface and a second filtering surface are oppositely arranged on the side surface of the filtering part. Filter membranes are arranged at the first filtering surface and the second filtering surface. An embedded core is arranged in the filtering cavity. The embedded core is located between the first filtering surface and the second filtering surface. The front surface of the embedded core has a first surface, and the back surface of the embedded core has a second surface. The first surface is directly opposite to the first filtering surface, so that there is a first gap between the first surface and the first filtering surface. The second surface is directly opposite to the second filtering surface, so that there is a second gap between the second surface and the second filtering surface.

2. The inner tube according to claim 1, characterized in that, A liquid extraction groove is formed in the embedded core. The notch of the liquid extraction groove faces the side where the port of the inner tube is located. The first gap and the second gap communicate with the liquid extraction groove respectively.

3. The inner tube according to claim 2, wherein The shape of the liquid extraction groove gradually becomes smaller from top to bottom, so that the shape of the liquid extraction groove matches the shape of the pipette tip.

4. The inner tube according to claim 3, wherein, An angle is formed between the first filtering surface and the vertical direction, and an angle is formed between the second filtering surface and the vertical direction. The first filtering surface and the second filtering surface are mirror-symmetrical.

5. The inner tube according to claim 1, wherein The embedded core and the inner tube are integrally formed. The value range of the angle is 1-10°.

6. The inner tube according to claim 1, characterized in that, The first surface is parallel to the first filtering surface, and the second surface is parallel to the second filtering surface. The gap widths of the first gap and the second gap are 0.05-1.5 mm.

7. The inner tube according to claim 6, wherein, The gap widths of the first gap and the second gap are 0.1-0.4 mm.

8. The inner tube according to 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 filtering cavity, so that the two sides of the embedded core are respectively positioned and clamped at both ends of the filtering cavity.

9. The inner tube according to claim 8, wherein Limit grooves are oppositely arranged on both sides of the inner wall of the inner tube. The limit grooves are arranged in the vertical direction. The two sides of the embedded core are respectively embedded in the limit grooves. The two sides of the embedded core are in interference fit with the limit grooves.

10. An ultrafiltration centrifuge tube, characterized in that, It includes the inner tube according to any one of claims 1-9. An outer tube is sleeved outside the inner tube. A filtered liquid cavity is formed between the outer wall of the inner tube and the inner wall of the outer tube. Pipe caps are provided at the ports of the inner tube and the outer tube. The inner tube and the outer tube are concentrically arranged.

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