Leaflet structure, method of making a leaflet structure, and valve prosthesis

Abstract

The application relates to the technical field of medical devices, and discloses a leaflet structure, a preparation method of the leaflet structure and a valve prosthesis. The leaflet structure comprises a leaflet body, the leaflet body comprises a fixed end, a free end and a side wall, the side wall extends from the fixed end to the free end, and the hydrophobicity of the side wall in the region close to the fixed end is greater than the hydrophobicity of the side wall in the region close to the free end. According to the leaflet structure, the hydrophobicity of the side wall close to the fixed end is designed to be greater than the hydrophobicity close to the free end, so that a humidity gradient effect is formed on the side wall, the leaflet body has the function of guiding fluid (i.e. blood) from one side close to the fixed end to one side close to the free end, the probability of blood deposition in the semi-closed region of the leaflet is reduced, and the service life of the leaflet structure is prolonged.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a leaflet structure, a method for preparing the leaflet structure, and a valve prosthesis. Background Technology

[0002] This section provides only background information relevant to this disclosure and is not necessarily prior art.

[0003] like Figure 1 and Figure 2 As shown, an artificial valve typically includes a leaflet structure 100 and a stent structure 210. A semi-closed region 119 with a one-sided opening is easily formed between the leaflet structure 100 and the stent structure 210. When blood flows into this semi-closed region 119, the blood flow velocity slows down, causing blood deposition and thrombus formation. The thrombus deposited in this semi-closed region 119 accumulates over a long period of time, forming a thrombus that compresses the closing movement of the leaflet structure 100, reduces the effective opening area of ​​the artificial valve, and thus accelerates the reduction of the lifespan of the leaflet structure 100. Summary of the Invention

[0004] The purpose of this application is to at least address the problem of blood deposition and thrombosis easily occurring in the semi-closed area between the leaflet and the stent of an artificial valve. This purpose is achieved through the following technical solution:

[0005] A first aspect of this application provides a leaflet structure including a leaflet body, the leaflet body including a fixed end, a free end and a sidewall, the sidewall extending from the fixed end to the free end, the sidewall having a greater hydrophobicity in the region near the fixed end than in the region near the free end.

[0006] According to the leaflet structure of this application, by designing the hydrophobicity of the sidewall near the fixed end to be greater than that near the free end, a wetting gradient effect is formed on the sidewall. The leaflet body has the function of guiding fluid (i.e., blood) from the side near the fixed end to the side near the free end. When the leaflet structure is assembled with the stent structure to form a valve prosthesis, the closed side of the semi-closed region is usually the position corresponding to the fixed end, and the open side of the semi-closed region is usually the position corresponding to the free end. By designing the hydrophobicity of the sidewall near the fixed end to be greater than that near the free end, it is beneficial for blood to flow out of the semi-closed region, reducing the probability of blood deposition in the semi-closed region of the leaflet and improving the service life of the leaflet structure.

[0007] In addition, the leaflet structure of this application may also have the following additional technical features:

[0008] In some embodiments of this application, the hydrophobicity of the sidewall decreases from the fixed end to the free end.

[0009] In some embodiments of this application, the sidewall is provided with a plurality of protrusions, and the plurality of protrusions are spaced apart;

[0010] Along the direction from the fixed end to the free end, the height of the protrusion near the fixed end is greater than the height of the protrusion near the free end, and / or, the cross-sectional area of ​​the protrusion near the fixed end is greater than the cross-sectional area of ​​the protrusion near the free end.

[0011] In some embodiments of this application, each of the protrusions extends in a strip shape along a first direction, and the plurality of protrusions are arranged in parallel in sequence along a second direction, wherein the first direction is perpendicular to the second direction.

[0012] In some embodiments of this application, a plurality of protrusions are provided on the sidewall, and the plurality of protrusions are arranged at intervals along the direction from the fixed end to the free end;

[0013] Along the direction from the fixed end to the free end, the spacing between adjacent protrusions among the plurality of protrusions increases.

[0014] In some embodiments of this application, the cross-sectional shape of the protrusion includes a square, a circle, or a triangle.

[0015] In some embodiments of this application, the leaflet body includes a woven mesh skeleton, the weaving density of the mesh skeleton near the fixed end is less than the weaving density near the free end, and the sidewall is the sidewall of the mesh skeleton.

[0016] In some embodiments of this application, the mesh skeleton includes multiple braided filaments, wherein the diameter of the braided filaments near the fixed end is smaller than the diameter of the braided filaments near the free end.

[0017] A second aspect of this application provides a valve prosthesis, comprising:

[0018] A support structure, wherein a tubular channel is formed on the inner side of the support structure;

[0019] The first aspect of this application provides a leaflet structure, wherein the leaflet structure is disposed inside the support structure, and the fixed end of the leaflet structure is connected to the support structure.

[0020] According to the valve prosthesis of this application, the closed side of the semi-closed region is usually the position corresponding to the fixed end, and the open side of the semi-closed region is usually the position corresponding to the free end. By designing the hydrophobicity of the sidewall near the fixed end to be greater than that near the free end, a humidity gradient effect is formed on the sidewall. The valve leaflet body has the function of guiding fluid (i.e. blood) from the side near the fixed end to the side near the free end, thereby facilitating the flow of blood out of the semi-closed region, reducing the probability of blood deposition in the semi-closed region of the valve leaflet, and improving the service life of the valve prosthesis.

[0021] The third aspect of this application discloses a method for preparing a leaflet structure, used to prepare the leaflet structure proposed in the first aspect of this application. The leaflet structure includes a leaflet body, the leaflet body including a fixed end, a free end, and a sidewall, the sidewall extending from the fixed end to the free end. The method for preparing the leaflet structure includes:

[0022] Provide the leaflet body;

[0023] The sidewall of the leaflet body is treated to be hydrophobic, such that the hydrophobicity of the sidewall in the region near the fixed end is greater than that in the region near the free end.

[0024] According to the method for preparing the leaflet structure of this application, when the processed leaflet structure is assembled with the stent structure to form a valve prosthesis, the closed side of the semi-closed region is usually the position corresponding to the fixed end, and the open side of the semi-closed region is usually the position corresponding to the free end. By designing the hydrophobicity of the sidewall near the fixed end to be greater than that near the free end, a humidity gradient effect is formed on the sidewall. The leaflet body has the function of guiding fluid (i.e., blood) from the side near the fixed end to the side near the free end, thereby facilitating the flow of blood out of the semi-closed region, reducing the probability of blood deposition in the semi-closed region of the leaflet, and improving the service life of the leaflet structure.

[0025] In addition, the method for preparing the leaflet structure according to this application may also have the following additional technical features:

[0026] In some embodiments of this application, the hydrophobic treatment of the sidewalls of the leaflet body includes:

[0027] The leaflet body is immersed in a PDMS solution to obtain the leaflet body with a PDMS coating on the sidewall;

[0028] A stamping element with a preset graphic structure on its surface is provided. The stamping element is used to press the leaf body with a PDMS coating on its sidewall to obtain a leaf structure in which the height of the protrusion near the fixed end is greater than the height of the protrusion near the free end in the direction from the fixed end to the free end, and / or the cross-sectional area of ​​the protrusion near the fixed end is greater than the cross-sectional area of ​​the protrusion near the free end. Attached Figure Description

[0029] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0030] Figure 1 A schematic diagram of the leaflet structure in the open state according to Embodiment 1 of this application is shown.

[0031] Figure 2 A schematic diagram of the leaflet structure in a closed state according to Embodiment 1 of this application is shown.

[0032] Figure 3 A schematic diagram of the leaflet structure according to Embodiment 1 of this application is shown;

[0033] Figure 4 A schematic diagram of a leaflet structure according to another embodiment of this application is shown;

[0034] Figure 5 A schematic diagram of the leaflet structure according to Embodiment 2 of this application is shown;

[0035] Figure 6 A schematic diagram of another leaflet structure according to Embodiment 2 of this application is shown;

[0036] Figure 7 A schematic diagram of another leaflet structure according to Embodiment 2 of this application is shown;

[0037] Figure 8 for Figure 7 A schematic diagram from one of the perspectives;

[0038] Figure 9 A schematic diagram of the leaflet structure according to Embodiment 3 of this application is shown;

[0039] Figure 10 for Figure 9 A schematic diagram of the TT cross-section in the diagram;

[0040] Figure 11 A schematic diagram of the leaflet structure according to Embodiment 4 of this application is shown;

[0041] Figure 12 A schematic diagram of a valve prosthesis according to Embodiment 5 of this application is shown. Figure 13 for Figure 12 A schematic diagram from one of the perspectives;

[0042] Figure 14 A schematic diagram of the engraving element according to Embodiment Six of this application is shown;

[0043] Figure 15 A flowchart illustrating the preparation method of the leaflet structure according to Embodiment Six of this application is shown schematically;

[0044] Figure 16 A flowchart illustrating the hydrophobic treatment of the sidewalls of the leaflet body according to Embodiment Six of this application is shown schematically.

[0045] The attached figures are labeled as follows:

[0046] 100. Leaflet structure; 110. Leaflet body; 111. Fixed end; 112. Free end; 113. Sidewall; 114. Mesh skeleton; 115. Inflow surface; 116. Outflow surface; 117. Fixed part; 118. Free part; 119. Semi-enclosed region; 120. Protrusion; 130. Groove; 141. First region; 142. Second region; 143. Third region; 144. Fourth region;

[0047] 200. Valve prosthesis; 210. Stent structure; 211. Drainage membrane;

[0048] 300. Engraved part; 310. Groove;

[0049] A. With the direction of blood flow; B. Against the direction of blood flow; C. First direction; D. Second direction. Detailed Implementation

[0050] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0051] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0052] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0053] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0054] Example 1

[0055] Embodiment 1 of the present invention provides a leaflet structure 100, including a leaflet body 110. The leaflet body 110 includes a fixed end 111, a free end 112 and a sidewall 113. The sidewall 113 extends from the fixed end 111 to the free end 112. The hydrophobicity of the sidewall 113 near the fixed end 111 is greater than that of the sidewall 113 near the free end 112.

[0056] The leaflet structure 100 can be used in the valve prosthesis 200, which can be inserted into the mitral, tricuspid, or aortic valve to replace or replace a damaged aortic, mitral, tricuspid, or pulmonary valve in the human body.

[0057] Reference Figures 1 to 3 The leaflet structure 100 includes a leaflet body 110, which can be made of biological tissue such as bovine pericardium or porcine pericardium, or it can be formed by weaving filaments. The leaflet body 110 includes a fixed portion 117 and a free portion 118, which are usually an integral structure. The fixed portion 117 is roughly semi-circular in shape, and the arcuate edge of the fixed portion 117 forms a fixed end 111, which is connected to the support structure 210 of the valve prosthesis 200. The free portion 118 is elongated, and the fixed portion 117 is integrally connected to the free portion 118. The end of the free portion 118 away from the fixed portion 117 forms a free end 112.

[0058] The free end 112 can move toward the side closer to the center of the stent structure 210 or toward the side farther away from the center of the stent structure 210. The valve prosthesis 200 includes an open state and a closed state. When the valve prosthesis 200 is in the open state, the free ends 112 of two adjacent leaflet structures 100 are spaced apart to form an opening for blood flow. When the valve prosthesis 200 is in the closed state, the free ends 112 of two adjacent leaflet structures 100 are abutted.

[0059] like Figure 3 As shown, the sidewall 113 includes a first region 141 and a second region 142 adjacent to each other in the direction from the fixed end 111 toward the free end 112. The first region 141 is disposed close to the fixed end 111, and the second region 142 is disposed close to the free end 112. The hydrophobicity of the first region 141 is greater than that of the second region 142. It should be noted that hydrophobicity and hydrophilicity are relative concepts; the stronger the hydrophobicity, the weaker the hydrophilicity, and vice versa. In this embodiment, the hydrophobicity and hydrophilicity of the first region 141 and the second region 142 can be tested by methods such as contact angle testing or Zeta potential analysis (Zeta is also known as Zeta potential, which refers to the potential of the shear surface).

[0060] In this way, by setting the sidewall 113 to be more hydrophobic near the fixed end 111 than near the free end 112, the surface of the sidewall 113 forms a structure with one side being more hydrophilic and the other side being more hydrophobic. When the fluid flows through the sidewall 113, under the action of the wetting gradient effect, the fluid will migrate from the hydrophobic side to the hydrophilic side, thereby guiding the fluid from the fixed end 111 to the free end 112.

[0061] Reference Figure 1 and Figure 2 The sidewall 113 of the leaflet body 110 includes an outflow surface 116 and an inflow surface 115 disposed opposite to each other. In this embodiment, the sidewall 113 can refer to either the outflow surface 116 or the inflow surface 115. The side through which blood flows in the direction of blood flow is defined as the outflow surface 116, and the other side as the inflow surface 115. This embodiment exemplifies the inflow surface 115 and the outflow surface 116 in the working state of the valve prosthesis 200 inserted into the pulmonary valve. Here, direction A is defined as the direction of blood flow, which refers to the direction in which blood passes through the leaflet structure 100 when the valve prosthesis 200 is open. Direction B is the direction of blood flow against the direction of blood flow, which is the opposite direction to the direction of blood flow A. (Refer to...) Figure 1 As shown, when blood flows in the direction of blood flow, the valve prosthesis 200 is in the open state, and blood flows through the inner side of the multiple leaflet structures 100; (Refer to...) Figure 2 As shown, when blood flows in the opposite direction, the valve prosthesis 200 is in a closed state to prevent backflow.

[0062] In this embodiment, the hydrophobicity of the inflow surface 115 near the fixed end 111 is greater than that near the free end 112. When the blood flows into the semi-closed region 119, the blood flows towards the opening side of the semi-closed region 119 under the guidance of the sidewall, which reduces the possibility of blood deposition in the semi-closed region 119 and extends the service life of the leaflet structure 100.

[0063] It is understood that in some other embodiments, the hydrophobicity of the outflow surface 116 near the fixed end 111 can be greater than that near the free end 112, so that the outflow surface 116 can promote blood flow in a set direction (that is, the direction from the fixed end 111 to the free end 112, specifically referring to the first direction C). This can cause more blood to gather towards the free end 112 of the leaflet structure 100 during the flow process, increasing the blood pressure on the free end 112, thereby enabling the free end 112 to unfold more fully and reducing the probability that the leaflet body 110 is not fully opened.

[0064] It is understood that in some other embodiments, the hydrophobicity near the fixed end 111 can be greater than that near the free end 112 on both the inlet surface 115 and the outlet surface 116.

[0065] The hydrophobicity of the sidewall 113 decreases from the fixed end 111 to the free end 112.

[0066] Hydrophobicity gradually decreases from the fixed end 111 to the free end 112, or hydrophilicity gradually increases from the fixed end 111 to the free end 112, creating a gradient of decreasing hydrophobicity or increasing hydrophilicity on the surface of the sidewall 113. For example, in one embodiment, such as Figure 4 As shown, the sidewall 113 includes a first region 141, a second region 142, a third region 143, and a fourth region 144. The first region 141, the second region 142, the third region 143, and the fourth region 144 are arranged adjacent to each other in the direction from the fixed end 111 toward the free end 112. The hydrophobicity of the first region 141 is greater than that of the second region 142, the hydrophobicity of the second region 142 is greater than that of the third region 143, and the hydrophobicity of the third region 143 is greater than that of the fourth region 144. Thus, the hydrophobicity increases from the first region 141 to the fourth region 144. It is understood that the division of the first region 141, the second region 142, the third region 143 and the fourth region 144 is only an illustrative example. This embodiment does not limit the number of regions on the sidewall 113. It can be five regions, six regions or even ten regions, as long as the hydrophobicity decreases from the fixed end 111 to the free end 112 or the hydrophilicity increases from the fixed end to the free end.

[0067] This creates a gradual gradient wetting effect on the sidewall 113 from the fixed end 111 to the free end 112. When blood is at any position on the sidewall 113, it will flow towards the free end 112 due to the difference in hydrophobicity between its position and its adjacent positions. This facilitates the flow and guidance of blood towards the free end 112, further reducing the probability of blood deposition.

[0068] In this embodiment, the difference in hydrophilicity or hydrophobicity between different regions on the sidewall 113 can be achieved by applying different hydrophobic or hydrophilic coatings to the sidewall 113. For example, in one embodiment, a hydrophobic coating can be applied to the first region 141, and a hydrophilic coating can be applied to the second region 142, so that the hydrophobicity of the first region 141 is greater than that of the second region 142. The hydrophobic coating can be PDMS, paraffin, etc., and the hydrophilic coating can be PEG, polyacrylic acid, etc. Accordingly, the sidewall 113 is divided into multiple regions, and hydrophobic coatings with different hydrophobicities are applied to each of the multiple regions to achieve a decrease in the hydrophobicity of the sidewall 113 from the fixed end 111 to the free end 112.

[0069] Example 2

[0070] The difference between this embodiment and Embodiment 1 is that, as Figures 5 to 8 As shown, a plurality of protrusions 120 are provided on the side wall 113, and the plurality of protrusions 120 are spaced apart; along the direction from the fixed end 111 to the free end 112, that is, the first direction C, the height L of the protrusion 120 near the fixed end 111 is greater than the height L of the protrusion 120 near the free end 112, and / or, the cross-sectional area of ​​the protrusion 120 near the fixed end 111 is greater than the cross-sectional area of ​​the protrusion 120 near the free end 112.

[0071] The protrusion 120 refers to a structure that protrudes from the surface of the sidewall 113. The height L of the protrusion 120 refers to the distance between its two ends perpendicular to the sidewall 113, and the height L is between 2 micrometers and 30 micrometers. Specifically, the height L can be 2 micrometers, 5 micrometers, 10 micrometers, 15 micrometers, 20 micrometers, 25 micrometers, or 30 micrometers. The cross-sectional area of ​​the protrusion 120 refers to the cross-sectional area of ​​the protrusion 120 parallel to the sidewall 113. The cross-sectional area of ​​the protrusion 120 near the fixed end 111 is larger than that of the protrusion 120 near the free end 112. The cross-sectional area of ​​the protrusion 120 is set to between 5 square micrometers and 300 square micrometers. Specifically, the cross-sectional area of ​​the protrusion 120 can be 5 square micrometers, 20 square micrometers, 50 square micrometers, 100 square micrometers, 150 square micrometers, or 300 square micrometers. In this embodiment, the protrusion 120 exhibits a micropattern structure, that is, the width of the protrusion 120 and the spacing between two adjacent protrusions 120 are micrometers in size. The structural dimensions of the protrusion 120 in this embodiment can be obtained by observation using an electron microscope or a scanning electron microscope. Figures 5 to 7 As shown, the protrusion 120 can be cylindrical, cuboid, or triangular prism. The protrusion 120 can be formed by electrospinning on the surface of the leaflet body 110, or by coating the surface of the leaflet body 110 with a hydrophilic or hydrophobic coating, and then laser etching or imprinting the coating.

[0072] In this embodiment, as Figures 7 to 8As shown, multiple protrusions 120 have a columnar structure and are arrayed on the sidewall 113. Any two adjacent protrusions 120 are spaced apart, forming a grid-like structure. The spacing between two adjacent protrusions 120 is between 20 micrometers and 200 micrometers, specifically 20 micrometers, 40 micrometers, 50 micrometers, 80 micrometers, 90 micrometers, 100 micrometers, 150 micrometers, 180 micrometers, and 200 micrometers. Along the direction from the fixed end 111 to the free end 112 (i.e., the first direction C), the height L of the protrusion 120 near the fixed end 111 is greater than the height L of the protrusion 120 near the free end 112. It is understandable that, for micropatterns, within a certain height range, the height of the protrusion 120 and the contact angle between the sidewall 113 and the fluid are directly proportional. The greater the height of the protrusion 120, the larger the contact angle between the fluid and the sidewall 113, thus making the sidewall 113 more hydrophobic (i.e., less hydrophilic). Through the height difference of the protrusions 120, a hydrophobicity difference is formed on the sidewall 113. On the basis of the hydrophilicity-hydrophobicity difference already existing on the sidewall 113 of the leaflet body 110, the difference in hydrophilicity-hydrophobicity is further amplified by setting the pattern structure on the sidewall 113, thereby increasing the guiding effect of the sidewall 113 on the fluid and further reducing the probability of blood deposition in the semi-enclosed area 119. It is also understandable that, in some embodiments, the height of the protrusion 120 can be set to decrease from near the fixed end 111 to the free end 112 to increase the hydrophilicity-hydrophobicity difference at the interface, thereby further enhancing the guiding effect of the sidewall 113 on the fluid.

[0073] In other embodiments, the protrusions 120 are designed such that the end face surface area of ​​the protrusions 120 near the fixed end 111 is greater than the end face surface area near the free end 112. The end face refers to the end face of the protrusion 120 away from the side wall 113. It can be understood that within a certain range, the larger the end face surface area of ​​the protrusion 120, the larger its contact angle with the fluid, and the stronger the hydrophobicity. Thus, through the difference in end face surface area between the protrusions 120 and the region near the fixed end 111 and the region away from the fixed end 111, the side wall 113 forms a hydrophobicity difference in the region near the fixed end 111 and the region near the free end 112, further increasing the hydrophilicity-hydrophobicity difference of the side wall surface structure and enhancing the guiding effect of the side wall 113 on the fluid.

[0074] In other embodiments, in the direction from the fixed end 111 to the free end 112, the distance between two adjacent protrusions 120 increases from the fixed end 111 to the free end 112. The distance between two adjacent protrusions is inversely proportional to the contact angle of the fluid on the sidewall; the larger the distance, the smaller the contact angle. This makes the hydrophobicity of the sidewall 113 greater in the region near the fixed end than in the region near the free end, further increasing the hydrophilicity-hydrophobicity difference of the sidewall surface structure and enhancing the guiding effect of the sidewall 113 on the fluid. The adjacent distances are set to 0.5, 1, 1.5, 2, 2.5, and 3 times the diameter of the adjacent protrusions 120.

[0075] In this embodiment, the protrusions 120 are designed such that the cross-sectional area of ​​the protrusions 120 near the fixed end 111 is greater than the cross-sectional area near the free end 112, and the height L of the protrusions 120 near the fixed end 111 is greater than the height L of the protrusions 120 near the free end 112.

[0076] Example 3

[0077] The difference between this embodiment and Embodiment 1 is that, referring to... Figures 9 to 10 As shown, a plurality of protrusions 120 are provided on the side wall 113. Each protrusion 120 extends in a strip shape along the first direction C. The plurality of protrusions 120 are arranged in parallel along the second direction D. The first direction C is perpendicular to the second direction D.

[0078] It should be noted that the protrusion 120 in this embodiment exhibits a micro-patterned structure, that is, the width of the protrusion 120 and the spacing between two adjacent protrusions 120 are micrometer-sized micro-patterned structures. The structure and dimensions of the protrusion 120 in this embodiment can be obtained by observation using an electron microscope or a scanning electron microscope. The protrusion 120 can be cylindrical, cuboid, or triangular prism-shaped. The protrusion 120 can be formed by electrospinning on the surface of the leaflet body 110, or by coating the surface of the leaflet body 110 with a hydrophobic or hydrophilic coating, and then laser etching or imprinting the corresponding coating.

[0079] In this embodiment, as Figure 9 and Figure 10As shown, the first direction C is the direction from the fixed end 111 to the free end 112, and the second direction D is the direction perpendicular to the direction from the fixed end 111 to the free end 112. Multiple protrusions 120 are spaced apart from each other along the second direction D. A groove 130 extending from the fixed end 111 to the free end 112 is formed between adjacent protrusions 120. The width of the groove 130 is between 10 micrometers and 100 micrometers, specifically 10 micrometers, 20 micrometers, 30 micrometers, 40 micrometers, 50 micrometers, 60 micrometers, 70 micrometers, 80 micrometers, 90 micrometers, 100 micrometers, etc. In this embodiment, each protrusion 120 extends from the fixed end 111 to the free end 112. The height L of each protrusion 120 at the fixed end 111 is greater than its height L at the free end 112, and the height L of each protrusion 120 decreases from the fixed end 111 to the free end 112.

[0080] In this embodiment, the width W of each protrusion 120 near the fixed end 111 is greater than the width W of the free end 112, and the width W of each protrusion 120 decreases from the fixed end 111 toward the free end 112.

[0081] In this way, by the difference in height L and / or width W of each protrusion 120 in the direction from the fixed end 111 to the free end 112, a structural hydrophilicity-hydrophobicity difference is formed on the sidewall 113, thereby realizing the flow of fluid on the sidewall 113. Furthermore, by setting the protrusions 120 to extend along the first direction C and the multiple protrusions 120 to be spaced apart along the second direction D, the protrusions 120 form grooves 130 on the surface of the sidewall 113 along the first direction C. Thus, under the guidance of the grooves 130, the fluid moves directionally from the fixed end 111 to the free end 112, further enhancing the flow of fluid in the direction from the fixed end 111 to the free end 112.

[0082] Example 4

[0083] The difference between this embodiment and Embodiment 1 is that, as Figure 11 As shown, the leaflet body 110 includes a woven mesh skeleton 114. The weaving density of the mesh skeleton 114 near the fixed end 111 is less than the weaving density near the free end 112. The sidewall 113 is the sidewall 113 of the mesh skeleton 114.

[0084] It should be noted that weaving density refers to the number of intersections of the weaving threads per unit area. The mesh skeleton 114 forms the supporting structure of the leaf body 110.

[0085] In this embodiment, the mesh skeleton 114 requires the weaving threads to cross each other during weaving. The same weaving thread typically needs to cross multiple weaving threads (weaving threads typically need to be cross-woven; the crossing threads can be divided into warp and weft threads; the same warp thread needs to cross multiple weft threads, and the same weft thread needs to cross multiple warp threads). In one specific implementation, the number of weaving threads (corresponding to weft threads) of the same length (the weaving thread here can be a warp thread, and the weft threads that cross later are weft threads) crossing the fixed end 111 is less than the number of weaving threads (also corresponding to weft threads) crossing the free end 112. This results in the mesh skeleton 114 having fewer intersections of weaving threads near the fixed end 111 than near the free end 112, thereby achieving a weaving density in the mesh skeleton 114 that is lower than the weaving density near the free end 112. For example, in one embodiment, the mesh skeleton 114 includes a first region and a second region, the first region being disposed near the fixed end and the second region being disposed near the free end, and the number of weaving intersections of the braided wires in the first region being less than the number of weaving intersections of the braided wires in the second region.

[0086] In this embodiment, different areas on the surface of the mesh skeleton 114 are also coated with a hydrophobic coating or a hydrophilic coating. The hydrophobicity of the hydrophobic coating or the hydrophilic coating increases from the fixed end 111 toward the free end 112. The surface of the coating is provided with the aforementioned protrusions 120.

[0087] Because the mesh skeleton 114 has a lower weaving density near the fixed end 111, it is more prone to deformation in this region. Consequently, during the opening and closing of the valve structure 100, the blood flow pressure on the outflow surface 116 is greater. The braided fibers tend to shift from the end near the free end 112 towards the fixed end 111, reducing the distance between adjacent protrusions 120. This increases the contact angle of the fluid near the fixed end 111, increasing the hydrophobicity at the fixed end 111 and the difference in hydrophobicity between the fixed end 111 and the free end 112 of the outflow surface 116, thus enhancing the fluid guidance effect. Furthermore, the opening and closing of the valve structure 100 coincides with the reverse flow of blood, facilitating the removal of blood from the semi-enclosed area.

[0088] It is understood that in other embodiments, the number of braided filaments on the side near the fixed end 111 is limited, so that the number of braided filaments on the fixed end 111 side is less than the number of braided filaments on the free end 112 side. This results in the mesh area of ​​the mesh skeleton 114 on the side near the fixed end 111 being greater than the mesh area of ​​the mesh skeleton 114 on the side near the free end 112, thereby achieving a braiding density of the mesh skeleton 114 near the fixed end 111 being less than the braiding density near the free end 112.

[0089] It is understood that in other embodiments, the mesh skeleton 114 includes multiple braided filaments, and the diameter of the braided filaments near the fixed end 111 is smaller than the diameter of the filaments near the free end 112. Here, the diameter of the braided filaments refers to the diameter of a single filament.

[0090] The diameter of the filament near the fixed end 111 is smaller than that near the free end 112. This makes it easier for the braided filaments near the fixed end 111 to deform during the opening or closing of the valve structure 100. This facilitates the gathering of the braided filaments towards the side near the fixed end 111, which in turn helps the braided filaments to pull the protrusions 120 towards the fixed end 111. This, in turn, helps to create a higher hydrophobic difference between the fixed end 111 and the free end 112, promoting the flow of blood from the fixed end 111 to the free end 112.

[0091] It is understood that in other embodiments, at least a portion of the braided filaments near the fixed end 111 have greater elasticity than the braided filaments near the free end 112. This difference in braided filament elasticity can similarly achieve the effect of promoting deformation of the mesh skeleton 114 on the side near the fixed end 111 during the opening or closing of the leaf-shaped structure 100.

[0092] Example 5

[0093] Reference Figure 12 and Figure 13 As shown, this embodiment also provides a valve prosthesis 200, including a stent structure and a leaflet structure 100. A lumen channel is formed on the inner side of the stent structure. The leaflet structure 100 is the leaflet structure 100 proposed in this embodiment, which is disposed on the inner side of the stent structure, and the fixed end 111 of the leaflet structure 100 is connected to the stent structure.

[0094] The fixed end 111 of the leaflet structure 100 can be sewn onto the support structure. A flow-blocking membrane 211 is provided on the side wall 113 of the support structure, and the flow-blocking membrane 211 and the closed leaflet structure 100 together form a semi-closed area 119.

[0095] According to the valve prosthesis 200 of this application, the closed side of the semi-closed region corresponds to the fixed end 111, and the open side of the semi-closed region corresponds to the free end 112. By designing the hydrophobicity of the sidewall 113 near the fixed end 111 to be greater than that near the free end 112, a wetting gradient effect is formed on the sidewall 113. The leaflet body 110 has the function of guiding fluid (i.e., blood) from the side near the fixed end 111 to the side near the free end 112, thereby facilitating the outflow of blood from the semi-closed region, reducing the probability of blood deposition in the semi-closed region 119 of the leaflet, and improving the service life of the valve prosthesis 200.

[0096] Example 6

[0097] Reference Figures 14 to 16 As shown, this embodiment also provides a method for preparing a leaflet structure 100, used to prepare the leaflet structure 100 proposed in this embodiment. The leaflet structure 100 includes a leaflet body 110, which includes a fixed end 111, a free end 112, and a sidewall 113, with the sidewall 113 extending from the fixed end 111 to the free end 112. The method for preparing the leaflet structure 100 includes:

[0098] Step S1: Provide the leaflet body 110.

[0099] The leaflet body 110 can be made of biological tissues such as bovine pericardium or porcine pericardium, or it can be woven from filaments.

[0100] Step S2: Perform hydrophobic treatment on the sidewall 113 of the leaflet body 110 so that the hydrophobicity of the sidewall 113 in the region near the fixed end 111 is greater than that in the region near the free end 112.

[0101] According to the preparation method of the leaflet structure 100 in this embodiment, when the processed leaflet structure 100 is assembled with the stent structure to form a valve prosthesis 200, the closed side of the semi-closed region is usually the position corresponding to the fixed end 111, and the open side of the semi-closed region is usually the position corresponding to the free end 112. By designing the hydrophobicity of the sidewall 113 near the fixed end 111 to be greater than that near the free end 112, a wetting gradient effect is formed on the sidewall 113. The leaflet body 110 has the function of guiding fluid (i.e., blood) from the side near the fixed end 111 to the side near the free end 112, thereby facilitating the flow of blood out of the semi-closed region, reducing the probability of blood deposition in the semi-closed region 119 of the leaflet, and improving the service life of the leaflet structure 100.

[0102] like Figure 14 As shown, in one embodiment of this invention, hydrophobic treatment of the sidewall 113 of the leaflet body 110 includes:

[0103] Step S21: Immerse the leaflet body 110 in a PDMS (Polydimethylsiloxane) solution to obtain a leaflet body 110 with a PDMS coating on the sidewall 113.

[0104] Before being immersed in the PDMS solution, the leaflet body 110 is dried to give it a porous structure. The specific drying method for the leaflet body 110 can be freeze-drying, typically for about 12 hours; or critical point drying, typically for about 2 hours.

[0105] In step S21, the PDMS solution is specifically used to immerse the porous structure of the leaflet tissue and maintain the immersion for 1 to 6 hours to ensure sufficient immersion, thereby obtaining a leaflet body 110 with a PDMS coating on the sidewall 113.

[0106] It should be noted that the leaflet body 110 is usually immersed at low temperature, that is, the leaflet body 110 is immersed in a PDMS solution at a low temperature, and curing is usually carried out within the range of 10℃-37℃. A curing agent can usually be added to the PDMS solution. The crosslinking rate is slower at low temperature than at room temperature, which can promote the filling of PDMS in the porous structure.

[0107] Step S22: Provide an engraving 300 with a preset graphic structure on its surface, and use the engraving 300 to press the leaf body 110 with a PDMS coating on the sidewall 113 to obtain a leaf structure in the direction from the fixed end 111 to the free end 112 (refer to the first direction C), where the height of the protrusion 120 near the fixed end 111 is greater than the height L of the protrusion 120 near the free end 112, and / or the cross-sectional area of ​​the protrusion 120 near the fixed end 111 is greater than the cross-sectional area of ​​the protrusion 120 near the free end 112.

[0108] The etched part 300 can be a photolithographic silicon wafer. The processing method of the photolithographic silicon wafer is roughly as follows: select a silicon wafer substrate, the shape and size of which can be the same as the leaf structure 100; then use laser engraving to impart a certain preset graphic structure on the silicon wafer substrate according to the set program.

[0109] The preset graphic structure is adapted to the shape of the protrusion 120. The preset graphic structure is usually a groove 310 on the engraving part 300, and each groove 310 forms a protrusion. The depth of each groove 310 corresponds to the height L of the protrusion 120 to be formed, and the width of each groove 310 corresponds to the cross-sectional area of ​​the protrusion 120 to be formed. That is, the larger the width of the groove 310, the larger the cross-sectional area of ​​the corresponding protrusion 120.

[0110] like Figure 14 As shown, the groove 310 on the engraved part 300 can be a circular groove, and the correspondingly processed leaf structure 100 has such Figures 10 to 12 The cylindrical protrusion 120 shown; the groove 310 on the engraved part 300 can also be a square groove, and the correspondingly processed leaf structure 100 has such Figures 4 to 6 The cuboid protrusion 120 shown; the groove 310 on the engraved part 300 can also be a triangular groove, and the correspondingly processed leaf-shaped structure 100 has such Figures 5 to 7 The triangular prism-shaped protrusion 120 shown.

[0111] The embossing element 300 is used to press the leaflet body 110 with a PDMS coating on its sidewall 113. Specifically, the leaflet body 110 with a PDMS coating on its sidewall 113 can be placed on the embossing element 300, and a flat pressing method (specifically, the embossing element 300 presses the leaflet body 110) is used to control the thickness h of the leaflet structure 100 to be equal to h0 plus 0.01 mm to 0.1 mm. Specifically, h can be (h0 + 0.01) mm, h = (h0 + 0.05) mm, or h = (h0 + 0.1) mm. Here, h0 is the thickness of the leaflet body 110, that is, the overall thickness of the leaflet structure 100 with the protrusion 120 is 0.1 mm to 1 mm thicker than the thickness h0 of the leaflet body 110. When both sides of the leaflet body 110 have protrusions 120, an imprinting element 300 can be provided on both sides of the leaflet body 110. Then, by pressing the imprinting elements 300 on both sides, protrusions 120 are formed on both sides of the leaflet body 110. When one side of the leaflet body 110 has a protrusion 120, the leaflet body 110 can be loaded into a mold with the side where the protrusion 120 needs to be formed facing outwards from the mold. When imprinting is required, the side of the leaflet body 110 where the protrusion 120 needs to be formed faces the imprinting element 300, and the leaflet body 110 is placed on the imprinting element 300. The imprinting element 300 flattens the leaflet body 110, forming the protrusion 120 on the leaflet body 110.

[0112] During or after pressing the leaflet body 110 with a PDMS coating on the sidewall 113 using the embossing piece 300, the device is placed in an environment with a temperature of 30 to 60 degrees Celsius and maintained for a certain period of time to promote PDMS curing. Then, the leaflet structure 100 is gently peeled off from the embossing piece to obtain the leaflet structure 100 with protrusions.

[0113] It should be noted that the engraved part 300 is pre-processed, that is, before step S22, the engraved part 300 with corresponding grooves 310 is pre-processed according to the height L and / or cross-sectional area of ​​the protrusion 120 of the leaf structure 100. The engraved part 300 can be a reusable component or a disposable component.

[0114] The processing method of the leaflet structure 100 in this embodiment forms a hydrophobic difference on the sidewall 113 by the height difference L of the protrusion 120 and / or the difference in the cross-sectional area of ​​the protrusion 120 of the processed leaflet structure 100, so that the leaflet structure can guide blood from the fixed end 111 to the free end 112 and avoid blood deposition to form a thrombus.

[0115] It is understood that in some embodiments, a leaf structure 100 is formed by step S22 through an engraving member 300 corresponding to the groove shape, in which a plurality of protrusions 120 are sequentially spaced along the direction from the fixed end 111 to the free end 112 (refer to the first direction C), and the spacing between adjacent protrusions 120 gradually increases along the direction from the fixed end 111 to the free end 112 (refer to the first direction C). This difference in spacing between the plurality of protrusions 120 creates a hydrophobic difference on the sidewall 113, enabling the leaf structure to guide blood from the fixed end 111 to the free end 112, thus preventing blood from depositing and forming a thrombus.

[0116] Furthermore, after step S22, that is, after the protrusion 120 is constructed on the leaflet body 110, the leaflet structure 100 can be treated with plasma to make the hydrophilicity of the side near the fixed end 111 and the side near the free end 112 different. Specifically, the surface of the leaflet structure 100 can be plasma-treated using a low-temperature plasma device or a plasma treatment device. After the plasma treatment of the surface of the leaflet structure 100, the functional groups on the surface of the leaflet body 110 are changed to enhance the hydrophilicity.

[0117] Furthermore, the superhydrophobic surface can be transformed into a superhydrophilic surface through partial plasma treatment. Specifically, the surface of the leaflet structure 100 near the free end 112 is made into a superhydrophilic surface, which can further promote the flow of blood from the superhydrophobic region to the superhydrophilic region, that is, promote the flow of blood from the fixed end 111 of the leaflet body 110 to the free end 112.

[0118] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A leaflet structure, characterized in that, The valve leaflet structure comprises a valve leaflet body, the valve leaflet body comprises a fixed end, a free end and a side wall, the fixed end is used for connecting with a stent structure of a valve prosthesis, the side wall extends from the fixed end to the free end, the hydrophobicity of the side wall in the area close to the fixed end is greater than the hydrophobicity of the side wall in the area close to the free end, the hydrophobicity of the side wall decreases from the fixed end to the free end, and the valve leaflet body has an effect of guiding fluid from one side close to the fixed end to one side close to the free end.

2. The leaflet structure of claim 1, wherein, A plurality of protrusions are arranged on the side wall, and the plurality of protrusions are arranged in sequence in parallel. In the direction from the fixed end to the free end, the height of the protrusion close to the fixed end is greater than the height of the protrusion close to the free end, and / or the cross-sectional area of the protrusion close to the fixed end is greater than the cross-sectional area of the protrusion close to the free end.

3. The leaflet structure of claim 2, wherein, Each of the protrusions extends in a strip shape along a first direction, and the plurality of protrusions are arranged in sequence in parallel along a second direction, the first direction is perpendicular to the second direction, and the first direction is a direction from the fixed end to the free end.

4. The leaflet structure of claim 1, wherein, A plurality of protrusions are arranged on the side wall, and the plurality of protrusions are arranged in sequence in parallel. In the direction from the fixed end to the free end, the distance between adjacent protrusions in the plurality of protrusions increases.

5. The leaflet structure of claim 2, wherein, The cross-sectional shape of the protrusion comprises a square, a circle or a triangle.

6. The leaflet structure of claim 1, wherein, The valve leaflet body comprises a woven mesh framework, the weaving density of the woven mesh framework close to the fixed end is less than the weaving density of the woven mesh framework close to the free end, and the side wall is a side wall of the woven mesh framework.

7. The leaflet structure of claim 6, wherein, The woven mesh framework comprises a plurality of woven wires, and the wire diameter of the woven wire close to the fixed end is less than the wire diameter of the woven wire close to the free end.

8. A valve prosthesis, characterized in that, It comprises: A stent structure, the inner side of the stent structure forms a lumen passage; The valve leaflet structure of any one of claims 1-7 is arranged on the inner side of the stent structure, and the fixed end of the valve leaflet structure is connected with the stent structure.

9. A method for producing a leaflet structure for producing a leaflet structure according to any one of claims 1 to 7, characterized in that The valve leaflet structure comprises a valve leaflet body, the valve leaflet body comprises a fixed end, a free end and a side wall, the side wall extends from the fixed end to the free end, and the preparation method of the valve leaflet structure comprises: Providing the valve leaflet body; The side wall of the valve leaflet body is subjected to hydrophobic treatment, so that the hydrophobicity of the side wall in the area close to the fixed end is greater than the hydrophobicity of the side wall in the area close to the free end.

10. The method of claim 9, wherein the leaflet structure is prepared by, The hydrophobic treatment of the side wall of the valve leaflet body comprises: The valve leaflet body is soaked in a PDMS solution to obtain the valve leaflet body provided with a PDMS coating on the side wall; A stamping piece provided with a pre-designed pattern structure is provided, and the valve leaflet body provided with the PDMS coating on the side wall is pressed by using the stamping piece to obtain the valve leaflet structure in which the height of the protrusion close to the fixed end is greater than the height of the protrusion close to the free end in the direction from the fixed end to the free end, and / or the cross-sectional area of the protrusion close to the fixed end is greater than the cross-sectional area of the protrusion close to the free end.

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