Device for extracting platelet-rich plasma

Abstract

The utility model belongs to the technical field of medical instrument preparation, and particularly relates to a device for extracting platelet-rich plasma. The device comprises a separation part, a syringe, an end cover, an isolation part and a piston, wherein the two ends of the separation part are detachably connected with the end cover and the syringe respectively; two ends of the isolation part are respectively connected with the end cover and the syringe; the piston is axially displaceable within the syringe. The separating part and the injection barrel can be separated into two independent spaces through the separating part, the piston can only axially move in the second cavity of the injection barrel, blood in the first cavity can be reliably metered, the proportion of anticoagulant to whole blood can be quantitatively achieved through the device, use of disposable consumables is reduced, and the cost is reduced. The method has the advantages of simple operation, low cost and high extraction efficiency.

Description

Technical Field

[0001] The present application belongs to the technical field of medical device preparation, and specifically relates to a device for extracting platelet-rich plasma. Background Art

[0002] Platelet-rich plasma (PRP) is a high-concentration plasma rich in platelets that is extracted from fresh whole blood after gradient centrifugation according to the different sedimentation rates of blood components during the centrifugation process. It is rich in a large number of biologically active substances and has the effects of rapid hemostasis, analgesia, and accelerated wound healing. Currently, the research and application of platelet-rich plasma (PRP) worldwide has covered cosmetic medicine, sports medicine, orthopedics, diabetic wound treatment, as well as dentistry, otolaryngology, neurosurgery, ophthalmology, urology, wound treatment and other medical fields.

[0003] In recent years, with the increasingly widespread application of PRP technology, preparations for extracting platelet-rich plasma have also been continuously introduced. In the process of preparing platelet-rich plasma, it is often necessary to add anticoagulants to whole blood to prevent blood coagulation from affecting the extraction effect of platelet-rich plasma. In the PRP extraction process, the anticoagulant is often added to the extraction equipment first, and then the whole blood is added to the extraction equipment. The whole blood flows through the flow path of the anticoagulant to mix with the anticoagulant, thereby achieving the effect of preventing blood coagulation. However, in order to ensure the best blood coagulation effect, the ratio of anticoagulant to whole blood must be guaranteed. At present, in order to ensure the realization of this ratio, it is necessary to pre-adjust the volume of the anticoagulant and whole blood in an additional disposable device, and then inject all the pre-adjusted volume of the anticoagulant and whole blood into the extraction equipment. This method has the disadvantages of cumbersome operation and high cost.

[0004] Therefore, there is an urgent need for a device for extracting platelet-rich plasma that can quantitatively achieve the ratio of anticoagulant to whole blood. Utility Model Content

[0005] The purpose of the present application is to provide a device for extracting platelet-rich plasma that can quantitatively achieve the ratio of anticoagulant to whole blood.

[0006] The embodiments of the present application can be implemented through the following technical solutions:

[0007] A device for extracting platelet-rich plasma comprises a separation part, a syringe, an end cover and a piston. The two ends of the separation part along its axial direction are detachably connected to the end cover and the syringe respectively, and the piston can be axially displaced in the syringe.

[0008] The device further comprises a separation part, one end of which along the axial direction is spirally connected to the end cover, and the other end of which can pass through the separation part and be connected to the injection barrel by interference fit, and the separation part can separate the separation part and the injection barrel into two independent spaces;

[0009] The injection cylinder includes a first cavity and a second cavity. The second cavity is located at a side away from the separation portion, and an inner wall of the second cavity cooperates with the piston. The piston can only be displaced in the second cavity along the axial direction of the second cavity.

[0010] Furthermore, the first cavity is a truncated cone-shaped hollow structure, and its inner diameter gradually decreases in a direction away from the second cavity.

[0011] Furthermore, the isolation part includes a connecting rod and a first matching part, and the connecting rod and the first matching part can form a channel for blood circulation;

[0012] One end of the connecting rod along the axial direction is spirally connected to the end cover, and the other end can abut against the first matching portion, and the first matching portion is interference-fitted with the top end of the injection barrel.

[0013] Furthermore, a limiting portion is arranged in the hollow pipe of the first matching portion, the bottom end of the connecting rod can abut against the top end of the limiting portion, and the first matching portion is made of soft material.

[0014] Furthermore, at least one limiting groove is axially provided on the connecting rod, the threaded hole of the end cover extends downward to form a protrusion, and the limiting groove cooperates with the inner wall of the protrusion through a sealing ring.

[0015] Further, the separation portion includes a third cavity and a fourth cavity, the third cavity and the fourth cavity are located on a side close to the injection cylinder, and the fourth cavity is located on a side close to the injection cylinder;

[0016] The upper part of the fourth cavity is a truncated cone structure, and its inner diameter gradually increases along the direction approaching the injection barrel; the lower part of the third cavity is an inverted truncated cone structure, and its inner diameter gradually increases along the direction approaching the end cover.

[0017] Preferably, the bottom angle of the fourth cavity frustum cross section is smaller than the bottom angle of the third cavity frustum cross section.

[0018] Preferably, the bottom angle of the fourth cavity frustum cross section is 30°, the bottom angle of the third cavity frustum cross section is 35°, a cylindrical through hole for liquid flow is provided in the limiting portion, and the diameter of the cylindrical through hole is 9 mm.

[0019] Furthermore, the syringe barrel further comprises a second matching portion, and the second matching portion matches with the bottom end of the fourth cavity to form a space for accommodating blood;

[0020] A through hole is formed on the second matching portion, and the through hole of the second matching portion is interference-fitted with the first matching portion.

[0021] Furthermore, a first through hole and a second through hole are formed on the end cover, a rubber plug is disposed in the first through hole, and a filter membrane is disposed in the second through hole.

[0022] The device for extracting platelet-rich plasma provided by the embodiments of the present application has at least the following beneficial effects:

[0023] (1) The isolating part in the present application can separate the separation part and the syringe into two independent spaces, and the piston can only be axially displaced in the second cavity of the syringe, so that the blood in the first cavity can be reliably measured. The device can not only quantitatively realize the ratio of anticoagulant to whole blood, but also realize the extraction of platelet-rich plasma, which not only ensures the extraction effect of platelet-rich plasma, but also reduces the use of disposable consumables, and has the advantages of simple operation, low cost and high extraction efficiency;

[0024] (2) The isolating part in the present application can separate the separation part and the syringe into two independent spaces, and the piston can only be axially displaced in the second cavity of the syringe, so that the blood in the first cavity can be reliably measured. The present application can adjust the ratio of anticoagulant to whole blood by adjusting the volume of the connecting rod, the first cavity and the second cavity;

[0025] (3) The upper part of the fourth cavity in the present application is a truncated cone structure, and the lower part of the third cavity is an inverted truncated cone structure. On the one hand, the inverted truncated cone structure of the third cavity can increase the blood flow rate to the fourth cavity; on the other hand, the truncated cone structure of the fourth cavity can weaken the siphon effect of the blood, preventing the blood in the fourth cavity from being drawn out when the end cap draws blood from the third cavity, thereby ensuring the efficiency and concentration of the preparation;

[0026] (4) The device in the present application can realize the overall extraction process without the need to use additional devices to adjust the capacity, which not only reduces the use of disposable consumables but also reduces the possibility of contamination. It has the advantages of low cost and high extraction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is an overall structural diagram of a device for extracting platelet-rich plasma in the present application;

[0028] Figure 2 An exploded view of a device for extracting platelet-rich plasma in the present application;

[0029] Figure 3 A perspective view of the device for extracting platelet-rich plasma when the connecting rod abuts against the first matching portion in the present application;

[0030] Figure 4 A perspective view of the device for extracting platelet-rich plasma when the connecting rod is separated from the first mating part in the present application;

[0031] Figure 5 This is an overall structural diagram of the first matching part in this application;

[0032] Figure 6 is the overall structural diagram of the end cover in this application;

[0033] Figure 7 The figure is an overall structural diagram of a device for extracting platelet-rich plasma with a piston push rod.

[0034] Figure numerals: 1. separation part, 11. third cavity, 12. fourth cavity, 2. injection cylinder, 21. first cavity, 22. second cavity, 3. end cover, 31. protrusion, 32. first through hole, 33. second through hole, 4. isolation part, 41. connecting rod, 42. first matching part, 421. limiting part, 4211. cylindrical through hole, 5. piston, 6. piston push rod. DETAILED DESCRIPTION

[0035] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

[0036] The vocabulary in this specification is used to illustrate the embodiments of the present application, but is not intended to limit the present application. Unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or a communication between the two components. For those skilled in the art, the specific meanings of the above terms in this application can be specifically understood.

[0037] In addition, in the description of the embodiments of the present application, various components on the drawings are enlarged or reduced in size for ease of understanding, but this practice is not intended to limit the scope of protection of the present application.

[0038] Figure 1 and Figure 2 They are respectively the overall structure diagram and the exploded diagram of the device for extracting platelet-rich plasma in the present application, such as Figure 1 and Figure 2As shown, the device comprises a separation part 1, a syringe 2, an end cover 3, a separation part 4 and a piston 5. The separation part 1 is detachably connected to the end cover 3 and the syringe 2 at both ends along its axial direction; one end of the separation part 4 is spirally connected to the end cover 3 along its axial direction, and the other end passes through the separation part 1 and is connected to the syringe 2 by interference fit. The separation part 4 can separate the separation part 1 and the syringe 2 into two independent spaces; the piston 5 can be axially displaced in the syringe 2 to change the pressure of the syringe 2, thereby realizing the blood entering and exiting the syringe 2.

[0039] The structure of the syringe 2 will be described in detail below. The syringe 2 includes a first cavity 21 and a second cavity 22 arranged along its axial direction, wherein the second cavity 22 is located on the side away from the separation portion 1 and is a cylindrical structure, and its inner wall cooperates with the piston 5. The piston 5 can only be displaced in the second cavity 22 along the axial direction of the second cavity 22, but cannot be displaced axially in the first cavity 21, so that the liquid in the first cavity 21 can be reliably measured.

[0040] In some specific embodiments of the present application, the first cavity 21 is a truncated cone-shaped hollow structure, and its inner diameter gradually decreases in the direction away from the second cavity 22. Since the inner diameter of the first cavity 21 is smaller than the inner diameter of the second cavity 22, when the piston 5 moves to the top of the second cavity 22, the piston 5 cannot enter the first cavity 21.

[0041] The structure of the isolation part 4 will be described in detail below. The isolation part 4 includes a connecting rod 41 and a first matching part 42. The connecting rod 41 and the first matching part 42 can form a pipeline for liquid circulation. One end of the connecting rod 41 along its axial direction is spirally connected to the end cover 3, and the other end can abut against the first matching part 42. The first matching part 42 is interference-fitted with the top end of the injection barrel 2. Figure 4 As shown, when the connecting rod 41 is screwed upward, the bottom end of the connecting rod 41 is separated from the first matching portion 42, and the separation portion 1 and the injection cylinder 2 form a connected cavity. When the piston 5 moves upward, the liquid in the injection cylinder 2 can flow through the first matching portion 42 and enter the separation portion 1; Figure 3 As shown, when the connecting rod 41 is screwed down, the bottom end of the connecting rod 41 abuts against the first matching portion 42 . At this time, the separation portion 1 and the injection barrel 2 are two independent spaces, and liquid cannot flow in the separation portion 1 and the injection barrel 2 .

[0042] Further, Figure 5 The overall structure of the first matching portion 42 is shown in FIG. Figure 5 As shown, a limiting portion 421 is provided in the hollow tube of the first matching portion 42 , and the bottom end of the connecting rod 41 can abut against the top end of the limiting portion 421 , thereby realizing axial limiting of the connecting rod 41 .

[0043] In some preferred embodiments of the present application, the first matching portion 42 is made of a soft material such as rubber, which can form a good sealing effect on the one hand, and can closely abut against the bottom end of the connecting rod 41 on the other hand, thereby enhancing the stability of the connection.

[0044] Furthermore, if Figure 1 As shown, the top end of the connecting rod 41 can be connected to the Luer connector, and the anticoagulant and whole blood can flow into the connecting rod 41 through the Luer connector.

[0045] Furthermore, if Figure 2 As shown, at least one limiting groove is formed in the circumference of the connecting rod 41, and the threaded hole of the end cover 3 extends downward to form a protrusion 31. The limiting groove cooperates with the inner wall of the protrusion 31 through a sealing ring to form a good sealing effect.

[0046] The structure of the separation unit 1 will be described in detail below. Figure 1 and Figure 2 As shown, the separation part 1 includes a third cavity 11 , and the third cavity 11 can accommodate the blood pushed by the syringe 2 .

[0047] In some preferred embodiments of the present application, the separation part 1 further includes a fourth cavity 12, the third cavity 11 and the fourth cavity 12 are arranged along the axial direction of the syringe 2, the fourth cavity 12 is located on the side close to the syringe 2, the upper part of the fourth cavity 12 is a truncated cone structure, and the inner diameter gradually increases along the direction close to the syringe 2; the lower part of the third cavity 11 is an inverted truncated cone structure, and the inner diameter gradually increases along the direction close to the end cap 3. On the one hand, the inverted truncated cone structure of the third cavity 11 can increase the rate of blood flowing into the fourth cavity 12; on the other hand, the truncated cone structure of the fourth cavity 12 can weaken the siphon effect of blood, prevent the end cap 3 from extracting blood from the third cavity 11, and ensure that the blood in the fourth cavity 12 will not be drawn away, thereby ensuring the efficiency and concentration of the preparation.

[0048] In some preferred embodiments of the present application, the bottom angle of the frustum cross section of the fourth cavity 12 is smaller than the bottom angle of the frustum cross section of the third cavity 11, which can further weaken the siphon effect of the fluid.

[0049] In some specific embodiments of the present application, the bottom angle of the frustum of the fourth cavity 12 is 30°, and the bottom angle of the frustum of the third cavity 11 is 45°.

[0050] In some specific embodiments of the present application, Figure 5 As shown, a cylindrical through hole 4211 for liquid flow is provided in the limiting portion 421, and the cylindrical through hole 4211 extends along the axial direction of the device and has a diameter of 9 mm. The number of platelets squeezed into the red blood cells through the first cavity 21 is significantly reduced, the detected red blood cell value is lower than 1.00, and the platelet recovery rate reaches 84%.

[0051] Furthermore, when the diameter of the cylindrical through hole 4211 is 6 mm, the platelets are squeezed through the first cavity 21 and the platelets are squeezed into the red blood cells. The red blood cell value is detected to be 0.03, and the platelet recovery rate reaches 67%.

[0052] Further, when the diameter of the cylindrical through hole 4211 is 8 mm, part of the platelets are squeezed into the red blood cells after passing through the first cavity 21, and the red blood cell value is detected to be 0.15, and the platelet recovery rate reaches 74%.

[0053] Further, when the diameter of the cylindrical through hole 4211 is 10 mm, part of the platelets squeezed through the first cavity 21 are squeezed into the red blood cells and reduced, and part of the red blood cells enter the fourth cavity 12, the red blood cell value is detected to be 1.43, and the platelet recovery rate reaches 82%.

[0054] Further, when the diameter of the cylindrical through hole 4211 is 11 mm, part of the platelets squeezed through the first cavity 21 are squeezed into the red blood cells and reduced, and part of the red blood cells enter the fourth cavity 12, the red blood cell value is detected to be 3.43, and the platelet recovery rate reaches 80%.

[0055] Furthermore, the syringe 2 further includes a second matching portion 23, which matches with the bottom end of the fourth cavity 12 to form a space for accommodating blood.

[0056] Furthermore, a through hole is formed on the second matching portion 23 , and the through hole of the second matching portion 23 is interference-fitted with the first matching portion 42 .

[0057] The structure of the end cover 3 will be described in detail below. Figure 6 As shown, a first through hole 32 is formed on the end cover 3 , a rubber plug is disposed in the first through hole 32 , and the needle of the syringe can pierce the rubber plug and extend into the third cavity 11 .

[0058] Furthermore, a second through hole 33 is provided on the end cover 3, and a filter membrane is arranged in the second through hole 33, which can not only achieve the effect of ventilation, but also filter out bacteria in the incoming air to prevent contamination of the blood.

[0059] It is conceivable that the axial displacement of the piston 5 in the syringe 2 can be achieved by the user manually driving the piston 5. In some preferred embodiments of the application, for example Figure 7 As shown, the device further comprises a piston push rod 6, which can drive the piston 5 to axially displace in the syringe 2, and has the advantages of labor saving and convenience.

[0060] The following is a detailed description of the method for extracting platelet-rich plasma from whole blood using the device, as follows:

[0061] S1: The connecting rod 41 abuts against the first matching portion 42, and the piston push rod 6 is pulled backward to draw the anticoagulant from the connecting rod 41 into the syringe 2;

[0062] S2: Push the piston push rod 6 forward until the piston 5 reaches the top of the second cavity 22, so that the anticoagulant fills the connecting rod 41 and the first cavity 21. At this time, the excess anticoagulant is discharged from the connecting rod 41;

[0063] S3: Pull the piston push rod 6 backward to draw the whole blood from the connecting rod 41 into the syringe 2 until the piston 5 reaches the bottom end of the second cavity 22, so that the whole blood fills the connecting rod 41, the first cavity 21, and the second cavity 22;

[0064] S4: Take out the piston push rod 6, and put the device into the centrifuge for the first centrifugation. After the first centrifugation is completed, connect the piston push rod 6 with the piston 5;

[0065] S5: The connecting rod 41 is screwed upward and separated from the first matching portion 42, and then the piston push rod 6 is pushed forward until the red-yellow boundary line reaches the top of the first cavity 21, at which time the supernatant mixed with platelet-rich plasma all enters the separation portion 1;

[0066] S6: The connecting rod 41 is screwed down until the bottom end of the connecting rod 41 abuts against the first matching portion 42, and the supernatant mixed with platelet-rich plasma is separated from the lower layer of red plasma rich in blood cells;

[0067] S7: Remove the piston push rod 6 and place the device into a centrifuge for a second centrifugation. After the second centrifugation is completed, the needle of the syringe passes through the end cover 3 and draws out the supernatant from the third cavity 11. At this time, the liquid left in the fourth cavity 12 is the extracted platelet-rich plasma.

[0068] Another method for extracting platelet-rich plasma from whole blood using the device is described in detail below:

[0069] S1: The connecting rod 41 abuts against the first matching portion 42, and the piston push rod 6 is pulled backward to draw the anticoagulant from the connecting rod 41 into the syringe 2;

[0070] S2: Push the piston push rod 6 forward until the piston 5 reaches the top of the second cavity 22, so that the anticoagulant fills the connecting rod 41 and the first cavity 21. At this time, the excess anticoagulant is discharged from the connecting rod 41;

[0071] S3: Pull the piston push rod 6 backward to draw the whole blood from the connecting rod 41 into the syringe 2 until the piston 5 reaches the bottom end of the second cavity 22, so that the whole blood fills the connecting rod 41, the first cavity 21, and the second cavity 22;

[0072] S4: Take out the piston push rod 6, and put the device into a centrifuge for centrifugation. After the centrifugation is completed, connect the piston push rod 6 with the piston 5;

[0073] S5: The connecting rod 41 is screwed upward and separated from the first matching portion 42, and then the piston push rod 6 is pushed forward until the white-red boundary line reaches the top of the first cavity 21, and at this time, the supernatant mixed with platelet-rich plasma all enters the separation portion 1;

[0074] S6: The connecting rod 41 is screwed down until the bottom end of the connecting rod 41 abuts against the first matching portion 42. At this time, the supernatant mixed with platelet-rich plasma is separated from the lower layer of red plasma rich in blood cells. The needle of the syringe passes through the end cover 3 and draws out the supernatant from the third cavity 11. At this time, the liquid left in the fourth cavity 12 is the extracted platelet-rich plasma.

[0075] That is, the device in the present application can extract platelet-rich plasma by one centrifugation or by two centrifugations. In actual production, the appropriate preparation method and centrifugation speed can be selected according to the concentration of whole blood to achieve the best preparation efficiency and concentration.

[0076] There are two types of devices currently available on the market that use double centrifugation to extract platelet-rich plasma: one is to move the part that needs secondary centrifugation to another tube for the second centrifugation through a syringe or a pipetting device after the first centrifugation. During the pipetting process, the platelets that have settled are shaken and re-melted in the syringe or the pipetting device, and the platelets collide with the device again, and some platelets are activated in advance, resulting in a low platelet recovery rate; the other type of double centrifugation is to invert the part after the first centrifugation in the same device. During the inversion process, the platelets that have already settled are re-melted. The platelets need to settle from the top to the bottom again after centrifugation. There is also a phenomenon that the platelets are re-activated, resulting in a low platelet recovery rate. The device in this application does not need to use two devices or inversion operations in the process of preparing PRP, which greatly reduces the probability of platelet re-melting and premature activation, and improves the recovery rate of platelets.

[0077] In summary, the volume of the anticoagulant in the device is the sum of the volumes of the connecting rod 41 and the first cavity 21, and the volume of the whole blood is the volume of the second cavity 22. By adjusting the volume ratio of the connecting rod 41, the first cavity 21, and the second cavity 22, the ratio of the anticoagulant and the whole blood can be prepared, thereby ensuring the effect of extracting platelet-rich plasma.

[0078] In some specific embodiments of the present application, the ratio of anticoagulant to whole blood is 1:9, that is, (volume of connecting rod 41 + volume of first cavity 21): volume of second cavity 22 = 1:9, that is, (volume of connecting rod 41 + volume of first cavity 21): (volume of connecting rod 41 + volume of first cavity 21 + volume of second cavity 22) = 1:10. In actual production, the volumes of connecting rod 41, first cavity 21, and second cavity 22 can be adjusted according to specific needs to adjust the ratio of anticoagulant to whole blood.

[0079] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A device for extracting platelet-rich plasma, comprising a separation portion (1), a syringe (2), an end cover (3) and a piston (5), wherein the separation portion (1) is detachably connected to the end cover (3) and the syringe (2) at both ends along its axial direction, and the piston (5) is axially displaceable in the syringe (2), characterized in that: It also comprises a separation part (4), one end of which along the axial direction is spirally connected to the end cover (3), and the other end of which can pass through the separation part (1) and be connected to the injection cylinder (2) by interference fit, and the separation part (4) can separate the separation part (1) and the injection cylinder (2) into two independent spaces; The injection cylinder (2) comprises a first cavity (21) and a second cavity (22), wherein the second cavity (22) is located on a side away from the separation portion (1), and an inner wall thereof cooperates with the piston (5), and the piston (5) can only be displaced in the second cavity (22) along the axial direction of the second cavity (22).

2. A device for extracting platelet-rich plasma according to claim 1, characterized in that: The first cavity (21) is a truncated cone-shaped hollow structure, and its inner diameter gradually decreases in a direction away from the second cavity (22).

3. The device for extracting platelet-rich plasma according to claim 1, characterized in that: The isolation part (4) comprises a connecting rod (41) and a first matching part (42), and the connecting rod (41) and the first matching part (42) can form a channel for blood circulation; One end of the connecting rod (41) along its axial direction is spirally connected to the end cover (3), and the other end can abut against the first matching portion (42), and the first matching portion (42) is interference-fitted with the top end of the injection cylinder (2).

4. The device for extracting platelet-rich plasma according to claim 3, characterized in that: A limiting portion (421) is arranged in the hollow pipe of the first matching portion (42), the bottom end of the connecting rod (41) can abut against the top end of the limiting portion (421), and the first matching portion (42) is made of a soft material.

5. The device for extracting platelet-rich plasma according to claim 3, characterized in that: At least one limiting groove is axially provided on the connecting rod (41), the threaded hole of the end cover (3) extends downward to form a protrusion (31), and the limiting groove cooperates with the inner wall of the protrusion (31) via a sealing ring.

6. The device for extracting platelet-rich plasma according to claim 3, characterized in that: The separation portion (1) comprises a third cavity (11) and a fourth cavity (12), wherein the third cavity (11) and the fourth cavity (12) are located on a side close to the injection cylinder (2), and the fourth cavity (12) is located on a side close to the injection cylinder (2); The upper portion of the fourth cavity (12) is a truncated cone-shaped structure, and its inner diameter gradually increases in a direction approaching the injection barrel (2); the lower portion of the third cavity (11) is an inverted truncated cone-shaped structure, and its inner diameter gradually increases in a direction approaching the end cover (3).

7. The device for extracting platelet-rich plasma according to claim 6, characterized in that: The bottom angle of the frustum cross section of the fourth cavity (12) is smaller than the bottom angle of the frustum cross section of the third cavity (11).

8. The device for extracting platelet-rich plasma according to claim 7, characterized in that: The bottom angle of the frustum cross section of the fourth cavity (12) is 30°, the bottom angle of the frustum cross section of the third cavity (11) is 35°, and a cylindrical through hole (4211) for liquid flow is provided in the limiting portion (421), and the diameter of the cylindrical through hole (4211) is 9 mm.

9. The device for extracting platelet-rich plasma according to claim 6, characterized in that: The syringe (2) further comprises a second matching portion (23), wherein the second matching portion (23) matches with the bottom end of the fourth cavity (12) to form a space for accommodating blood; A through hole is provided on the second matching portion (23), and the through hole of the second matching portion (23) is interference-fitted with the first matching portion (42).

10. The device for extracting platelet-rich plasma according to claim 1, characterized in that: The end cover (3) is provided with a first through hole (32) and a second through hole (33); a rubber plug is arranged in the first through hole (32), and a filter membrane is arranged in the second through hole (33).

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