A method for manufacturing a nano-plugging structure

Abstract

The application relates to a manufacturing method of a nano plugging structure, comprising the following steps: S100, obtaining PDO wires, a cylindrical base block and a PLLA flow resistance film; S200, weaving the PDO wires around the outer side of the cylindrical base block and integrally wrapping the whole cylindrical base block to form a first assembly; S300, immersing the first assembly into isopropyl alcohol for ultrasonic cleaning to obtain a cleaned assembly; S400, performing photoetching on at least one end surface of the cleaned assembly to obtain a second assembly; S500, dismounting the cylindrical base block on the second assembly to obtain a woven fabric; S600, heat setting the woven plugging device to obtain a woven plugging device; and S700, sewing the PLLA flow resistance film to the inside of the woven fabric. The super-hydrophilic structure is formed on the surface of the plugging structure which is in contact with blood, so that the plugging structure is prevented from forming a blood clot.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more specifically to a method for manufacturing a sealing structure. Background Technology

[0002] Traditional metal occluders have smooth surfaces, resulting in slow endothelialization (typically 3-6 months) and a long-term risk of thrombosis. Biodegradable occluders, compared to traditional metal occluders, shorten the endothelialization time to some extent (typically 1-3 months). However, cardiac implantable devices immediately affect hemodynamics within the heart after implantation, subsequently influencing thrombus formation on the device surface and the endothelialization process. In recent years, research into anticoagulation and endothelialization has focused on several directions: First, optimizing device design to reduce post-implantation surface area and better conform to surrounding tissue structures; second, using biocompatible and biodegradable polymers to provide a supportive path for cell climbing during the endothelialization stage, with no residue in long-term degradation; third, surface modification of devices or cholinergic membrane materials, such as fluorinated coatings (PTFE) cholinergic membranes, drug-impregnated coatings, or bioactive coatings (heparin, albumin, phosphorylcholine). Current surface modifications and coatings can reduce platelet activation and inflammatory responses to some extent, but existing coating technologies (such as heparin coatings) lack durability and are prone to detachment in the early stages of implantation. They cannot provide a sustained endothelialization-promoting coating, and their long-term effects are unclear. Furthermore, the effects of drug-coated coatings are not entirely controllable for different patients and are influenced by the patient's blood environment. Therefore, there is still a need in the field for biodegradable cardiac occluders with long-term anticoagulation and more stable endothelialization-promoting functions. Summary of the Invention

[0003] In view of this, the present invention provides a method for manufacturing a nano-blocking structure, wherein a first nano-tooth of a first preset array is formed on the target end face of the prepared blocking structure, so that a superhydrophilic structure is formed on the side of the blocking structure that is in contact with blood, thereby avoiding the formation of thrombi on the blocking structure.

[0004] The technical solution adopted in this invention:

[0005] A method for manufacturing a nanoblocking structure includes the following steps:

[0006] S100, obtain PDO filaments, cylindrical substrates and PLLA flow-blocking membranes;

[0007] S200: Weave PDO filaments around the outside of the cylindrical base block and wrap the entire cylindrical base block to form a first assembly;

[0008] S300. The first assembly is immersed in isopropanol for ultrasonic cleaning to obtain the cleaned assembly.

[0009] S400: Photolithography is performed on at least one end face of the cleaned assembly to obtain a second assembly;

[0010] S500, Remove the columnar base block from the second assembly to obtain the woven fabric;

[0011] S600, Heat set the woven fabric to obtain the woven plug;

[0012] S700, Sew the PLLA flow barrier membrane into the interior of the braided occluder;

[0013] In step S400, the end face of the second assembly undergoing photolithography is the target end face, and a first nanotooth of a first preset array is formed on the target end face. The first preset array is a matrix, and the first nanotooth is columnar. The top area S of the first nanotooth is 8000-20000 nm. 2 The tooth height H is 24-33 μm, and the spacing P between two adjacent first nanotooths is 1-2 μm.

[0014] Preferably, the tip of the first nanotooth is hemispherical.

[0015] Preferably, the PLLA flow-blocking membrane includes an end membrane.

[0016] In step S300, the end membrane is immersed in isopropanol for ultrasonic cleaning;

[0017] In step S400, the cleaned end film is photolithographically etched to obtain a photolithographic end film;

[0018] In step S700, the photolithographic end film is bonded to the inner side of the target end face, and the photolithographic end face of the photolithographic end film faces outward;

[0019] In step S400, a second nanotooth of a second preset array is formed on the photolithographic end film. The second preset array is a matrix, and the tip area S of the second nanotooth is 8000-250000 nm. 2 The tooth height is 15-25 μm, and the spacing P between two adjacent second nanotooths is 1-2 μm.

[0020] Preferably, the cleaned assembly and the photolithographic end film are collectively referred to as the target body, and step S400 includes...

[0021] S410. Photoresist is spin-coated onto the target end face of the target body using a spin coater to form a photoresist layer with a thickness of 120-160μm on the target end face. Then, it is baked in an oven at 90℃ for 2 minutes to obtain the target body with photoresist.

[0022] S420. Expose the target end face of the adhesive-coated target body through a grayscale mask, and then bake it in an oven at 90°C for 3 minutes to obtain the primary product.

[0023] S430. Soak the primary product in SU-8 developer for 2 minutes to remove the photoresist in the unexposed areas, rinse with deionized water for 30 seconds, blow dry with nitrogen, and finally cure in an oven at 90℃ for 10 minutes to obtain the second assembly and the photolithographic end film.

[0024] Preferably, in step S420, the exposure time is 60 seconds and the light intensity is 10 mW / cm². 2 .

[0025] Preferably, the method further includes the step of:

[0026] S800: Apply solution A and solution B to the primary sealing structure obtained in step S700 to form a hydrogel layer at the outer edge transition of the target end face of the primary sealing structure.

[0027] Solution A is an Alg / HA-BP solution; Solution B is a CaSO4 solution containing YAP / TAZ activating peptide, wherein the concentration of YAP / TAZ activating peptide is 10 μM, and CaSO4 is... 2+ Concentration 80mM.

[0028] Preferably, step S800 specifically includes:

[0029] S10, Obtain HA-BP and Alg-RGD-BP;

[0030] S20. Dissolve Alg-RGD-BP and HA-BP in HEPES to obtain an Alg / HA-BP solution, wherein the mass ratio of Alg-RGD-BP to HA-BP is 4:1 and the mass ratio of Alg-RGD-BP to Alg / HA-BP is 1:100.

[0031] S30. Cover the surface of the primary sealing structure with silicone or PTFE, wherein the surface of the primary sealing structure other than the outer edge transition of the photolithographic end is the covering surface.

[0032] S40. Apply solution A and solution B sequentially to the outer edge transition of the photolithographic end of the primary sealing structure, and crosslink solutions A and B at the outer edge transition to form a hydrogel layer.

[0033] Preferably, HA-BP is obtained using the following method:

[0034] MeHA was dissolved in triethanolamine buffer and stirred overnight to obtain solution number one.

[0035] Add 5.5 eq of thiol-BP and 7.5 mM of tris(2-carboxyethyl)phosphine hydrochloride to solution No. 1, stir and react for 48 h to obtain solution No. 2;

[0036] Solution No. 2 was dialyzed with deionized water for 3 days to obtain solution No. 3;

[0037] Solution No. 3 was frozen overnight at -30°C, then transferred to a lyophilizer for lyophilization to obtain HA-BP, which was then stored at -20°C.

[0038] Preferably, Alg-RGD-BP is obtained using the following method:

[0039] Dissolve 0.2 g of sodium alginate in 20 mL of L2-(N-morpholino)ethanesulfonic acid buffer, stir, and let stand overnight to obtain solution No. 4;

[0040] Add excess N-hydroxysulfosuccinimide, excess 1-ethyl-(3-dimethylaminopropyl)carbodiimide and excess bisphosphate to solution No. 4, stir and react for 24 h to obtain solution No. 5;

[0041] Solution No. 5 was dialyzed with deionized water for 3 days to obtain solution No. 6;

[0042] Solution No. 6 was frozen overnight at -30°C, then transferred to a lyophilizer to obtain Alg-RGD-BP, which was stored at -20°C.

[0043] The beneficial effects of this invention are:

[0044] This invention involves photolithography on at least one end face of the cleaned assembly to form a first nanotooth of a first predetermined array on the target end face. The first nanotooth is columnar, and the tip area S of the first nanotooth is 8000-20000 nm. 2 This results in the first nanotooth having a width of approximately 100-500 nm. The first nanotooth is arranged in a matrix, meaning that the row spacing and column spacing of the first nanotooth are both 1-2 μm. Therefore, the first nanotooth structure of the first preset array constitutes a superhydrophilic structure. After the occlusion structure is implanted into the patient's body, the target end face is in direct contact with the blood. The target end face mainly contacts the flowing blood, and a super-slippery and superhydrophilic structure is formed on the target end face. Blood will not coagulate on the target end face, avoiding the formation of thrombi on the occlusion structure, and facilitating the subsequent cell attachment to the target end face. Attached Figure Description

[0045] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0046] Figure 1This is a schematic diagram of the structure of the left atrial appendage occluder prepared according to the present invention;

[0047] Figure 2 This is a schematic diagram of a left atrial appendage occluder placed in the left atrial appendage;

[0048] Figure 3 This is a schematic diagram of the first nanotooth of the first preset array;

[0049] Figure 4 This is a comparison of the contact angles of blood droplets on the smooth surface of PLLA and the target end membrane;

[0050] Figure 5 A comparison of the coefficient of friction and frictional force of PLLA smooth surface and comb-shaped structure surface;

[0051] Figure 6 It is a comparison of endothelial cell proliferation before and after dynamic hydrogel coating;

[0052] Figure 7 This is a picture of an atrial septal occluder, where the white part inside is a PLLA flow-blocking membrane;

[0053] Figure 8 This is a comparison of the friction force and coefficient of friction of PDO smooth surface and comb-shaped structure surface. Detailed Implementation

[0054] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail, but well-known methods, processes, procedures, and elements are not described in detail in order to avoid obscuring the essence of the present invention.

[0055] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0056] Unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as encompassing rather than being exclusive or exhaustive; that is, meaning "including but not limited to."

[0057] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0058] See Figures 1-8 This invention provides a method for manufacturing a nano-occlusion structure, such as a left atrial appendage occluder or an atrial septum / ventricular septum occluder, the method comprising the steps of:

[0059] S100, obtain PDO filaments, cylindrical substrates and PLLA flow-blocking membranes;

[0060] S200: Weave PDO filaments around the outside of the cylindrical base block and wrap the entire cylindrical base block to form a first assembly;

[0061] S300. The first assembly is immersed in isopropanol for ultrasonic cleaning to obtain the cleaned assembly.

[0062] S400: Photolithography is performed on at least one end face of the cleaned assembly to obtain a second assembly;

[0063] S500, Remove the columnar base block from the second assembly to obtain the woven fabric;

[0064] S600, Heat set the woven fabric to obtain the woven plug;

[0065] S700, Sew the PLLA flow barrier membrane into the interior of the braided occluder;

[0066] In step S400, the end face of the second assembly undergoing photolithography is the target end face. A first nanotooth of a first preset array is formed on the target end face. The first preset array is a matrix, and the first nanotooth is columnar. The tip area S of the first nanotooth is 8000-250000 nm. 2 The tooth height H is 24-33 μm, and the spacing P between two adjacent first nanotooths is 1-2 μm.

[0067] The PDO yarn has a diameter of 0.1 mm. In step S200, a braided part with a braiding density of approximately 50 mesh is formed on the outside of the cylindrical base block. The braided part and the cylindrical base block together constitute the first assembly. Since the cylindrical base block is cylindrical and has two flat end faces, the first assembly is also cylindrical as a whole and has two basically flat end faces.

[0068] In step S300, the first assembly is immersed in isopropanol for ultrasonic cleaning for 10 minutes to remove surface contaminants. Then, the first assembly is subjected to plasma treatment with a mixture of Ar / O2 (the mixing ratio of the two is 3:1), which reduces the contact angle of the PDO filament surface from 75° to about 30°, thereby improving the hydrophilicity of the PDO filament surface.

[0069] If the occlusion structure is a left atrial appendage occluder, only one end face of the left atrial appendage occluder is in contact with blood. Therefore, in step S400, only one end face of the cleaned assembly needs to be photolithographically processed.

[0070] If the occlusion structure is an atrial septal / ventricular septal occluder, in step S400, photolithography needs to be performed on the two end faces of the cleaned assembly.

[0071] Due to photolithography, a first nanotooth array is formed on the target end face, meaning multiple first nanotooths are formed on the target end face. These multiple first nanotooths are arranged in a first preset array to cover the entire target end face. Microscopically, the cross-sectional area of ​​the first nanotooth can be circular or square, and the top surface area (corresponding to the cross-sectional area) of the first nanotooth is 8000-250000 nm. 2 The width of the first nanotooth is approximately 100-500 nm. The first nanotooth is arranged in a matrix, meaning that the row spacing and column spacing of the first nanotooth are both 1-2 μm. The radius of the blood droplet is approximately 25-50 μm. Therefore, when the blood droplet comes into contact with the target end face, the outermost first nanotooth presses against the blood, thereby reducing the contact area between the target end face and the blood droplet and reducing the friction between the two. Experiments show that this reduces the contact angle between the blood droplet and the target end face (see below), thereby preventing the formation of thrombi on the target end face. After the occlusion structure is implanted into the patient, the contact angle between the blood droplets and the target end face (superhydrophilic structure) is less than 10°. Therefore, the target end face is not superhydrophilic relative to the blood. As the blood flows through the target end face, the blood droplets can spread out on the target end face, forming a blood film. Thus, when the blood flows on the target end face, the blood droplets actually flow on the blood film, reducing the friction of the blood flowing on the target end face. In this way, the blood droplets will not aggregate on the target end face, and thrombi will not form on the target end face. After the left atrial appendage occluder is implanted, the tissue cells will climb along the left atrial appendage occluder. Since no thrombi will form on the target end face, the tissue cells can gradually cover the target end face of the left atrial appendage occluder, thereby closing the left atrial appendage. The PDO wire and PLLA choke membrane have biodegradable properties, so the cellular tissue will eventually close the left atrial appendage, thus achieving the purpose of the surgery.

[0072] In addition, the spacing P between the first nanotooth is 1-2 μm. Blood contains red blood cells, white blood cells and platelets. Among these three, platelets have the smallest radial size of 2-4 μm. Therefore, neither red blood cells, white blood cells or platelets in the blood will fall into the gaps between the tooth structure, thus eliminating the possibility of thrombus formation in terms of physical structure.

[0073] When blood flows across the target end face, the flowing blood continuously and dynamically replaces the blood forming the blood film. In other words, the blood forming the blood film is also dynamic, so the blood film will not solidify and form a thrombus.

[0074] Furthermore, the tip of the first nanotooth is hemispherical. This further reduces the friction between the blood droplet and the tip of the first nanotooth, preventing the formation of a thrombus on the target surface.

[0075] The PLLA flow-blocking membrane includes an end membrane.

[0076] In step S300, the end membrane is immersed in isopropanol for ultrasonic cleaning;

[0077] In step S400, the cleaned end film is photolithographically etched to obtain a photolithographic end film;

[0078] In step S700, the photolithographic end film is bonded to the inner side of the target end face;

[0079] In step S400, a second nanotooth of a second preset array is formed on the photolithographic end film. The second preset array is a matrix, and the tip area S of the second nanotooth is 8000-20000 nm. 2 The tooth height is 15-25 μm, and the spacing P between two adjacent second nanotooths is 1-2 μm.

[0080] In step S300, the end membrane and the first assembly are immersed in isopropanol for ultrasonic cleaning for 10 minutes to remove surface contaminants. Then, the first assembly and the end membrane are subjected to plasma treatment with a mixture of Ar / O2 (the mixing ratio of the two is 3:1), which reduces the contact angle of the PDO filament surface from 75° to about 30° and the contact angle of the end membrane surface from 80° to about 30°, thereby improving the hydrophilicity of the PDO filament surface.

[0081] Because braided occluders are made of PDO filaments, they inevitably have many pores. Therefore, when forming the occlusion structure, the PLLA flow barrier membrane is sewn into the inside of the braided occluder to prevent blood from entering the occlusion structure. As a result, in actual application, blood will inevitably come into contact with the PLLA flow barrier membrane, and blood will form a thrombus on the outside of the PLLA flow barrier membrane.

[0082] Therefore, this invention uses photolithography on the end membrane (the part of the PLLA flow barrier membrane that is in direct contact with blood) to form a superhydrophilic structure on the outer side of the end membrane that is similar to that on the target end surface. This gives the outer side of the end membrane superhydrophilicity as well. Since only the end membrane of the entire PLLA flow barrier membrane is in contact with blood, it can prevent blood from forming thrombi on the PLLA flow barrier membrane, thereby avoiding the formation of thrombi on the sealing structure.

[0083] The second nanotooth structure is similar to and has the same function as the first nanotooth structure. The difference lies in the specific size. Therefore, the specific principles and effects will not be elaborated here.

[0084] It should be noted that when the occlusion device is a left atrial appendage occluder, only one end membrane is needed; when the occlusion device is an atrial septal / ventricular septal occluder, two end membranes are needed.

[0085] Figure 4 As shown, the contact angle of a blood droplet with a radius of 25 μm on the smooth surface of the PLLA flow-blocking film (without photolithography) is 80°. According to the Cassie-Baxter theory, the theoretical contact angle of the comb-shaped surface is 5° (it can be clearly confirmed that the target end face of the present invention has superhydrophilic properties).

[0086] Figure 5 As shown, the solid-liquid contact area of ​​the smooth surface without photolithography is 3.2 × 10⁻⁶. -9 m 2 The coefficient of friction is 0.12, and the surface friction force is 0.006 μN; while on the comb-like surface, the theoretical apparent solid-liquid contact area is 1.5 × 10⁻⁶. -11 m 2 The coefficient of friction is 0.048, which is 60.00% lower than that of a smooth surface, and the surface friction force is 0.000037μN, which is 99.35% lower than that of a smooth surface.

[0087] Figure 8 As shown, the PDO smooth surface without photolithography has a contact angle of 75°, a friction coefficient of 0.148, and a surface friction force of 18.14 μN. However, after photolithography, the contact angle of the four samples is less than 10°, which is a superhydrophilic surface, and the friction force and friction coefficient are reduced by more than 90%.

[0088] Contact angle Coefficient of friction (mean ± standard deviation) Frictional force (mean ± standard deviation, μN) θ = 75.0° 0.1486±0.0048 18.14±0.29 θ = 8.2° 0.0021±0.0002 0.25±0.01 θ = 9.5° 0.0025±0.0002 0.31±0.02 θ = 7.8° 0.0018±0.0002 0.22±0.02 θ = 8.6° 0.0022±0.0002 0.26±0.02

[0089] Compared to the above two methods, the frictional force of blood droplets on the target membrane is reduced by nearly 110 times. Therefore, blood droplets are less likely to accumulate or remain on the target membrane, thus avoiding the formation of thrombi on the target membrane.

[0090] In another embodiment, a blood droplet with a radius of 50 μm has a contact angle of 85° on the smooth surface of the PLLA flow-blocking film (without photolithography) and a frictional force of 1.18 × 10⁻⁶. -10 N; A blood droplet with a radius of 50 μm has a contact angle of 35.9° on the target end film (photolithographically etched, with a second tooth structure) and a frictional force of 1.87 × 10⁻⁶. -11 N, the friction is reduced by nearly 63 times.

[0091] The cleaned assembly and the photolithographic end film are collectively referred to as the target body. Step S400 includes...

[0092] S410. Photoresist is spin-coated onto the target end face of the target body using a spin coater to form a photoresist layer with a thickness of 120-160μm on the target end face. Then, it is baked in an oven at 90℃ for 2 minutes to obtain the target body with photoresist.

[0093] S420. Expose the target end face of the adhesive-coated target body through a grayscale mask, and then bake it in an oven at 90°C for 3 minutes to obtain the primary product.

[0094] S430. Soak the primary product in SU-8 developer for 2 minutes to remove the photoresist in the unexposed areas, rinse with deionized water for 30 seconds, blow dry with nitrogen, and finally cure in a 90°C oven for 10 minutes to enhance structural stability, thus obtaining the second assembly and the photolithographic end film.

[0095] In step S420, the exposure time is 60 seconds and the light intensity is 10 mW / cm². 2 .

[0096] It also includes the following steps:

[0097] S800: Apply solution A and solution B to the primary sealing structure obtained in step S700 to form a hydrogel layer at the outer edge transition of the photolithographic end of the primary sealing structure.

[0098] Solution A is an Alg / HA-BP solution; Solution B is a CaSO4 solution with added YAP / TAZ activating peptide, wherein the concentration of YAP / TAZ activating peptide is 10 μM and the concentration of Ca2+ is 80 mM.

[0099] The thickness of the hydrogel layer is 10-20μm. Taking the left atrial appendage occluder as an example, the hydrogel layer is located on the surface of the left atrium that is in contact with blood (except for the photolithography end). The surface of the left atrial appendage occluder that is not in contact with blood is not provided with a hydrogel layer to avoid the friction between it and the left atrial appendage being too small and causing it to fall off.

[0100] The hydrogel layer facilitates the attachment of tissue cells (endothelial cells) to the hydrogel layer and allows them to proliferate to the edge of the photolithographic end. Since the photolithographic end is typically concave, tissue cells can easily cover it, thus sealing the entire sealing structure. Figure 6 (This indicates a 3-fold increase in endothelial cell proliferation rate).

[0101] Step S800 is as follows:

[0102] S10, Obtain HA-BP and Alg-RGD-BP;

[0103] S20. Dissolve Alg-RGD-BP and HA-BP in HEPES to obtain an Alg / HA-BP solution, wherein the mass ratio of Alg-RGD-BP to HA-BP is 4:1 and the mass ratio of Alg-RGD-BP to Alg / HA-BP is 1:100.

[0104] S30. Cover the surface of the primary sealing structure with silicone or PTFE (the surface that does not require hydrogel layer coverage), and the surface other than the outer edge transition of the photolithographic end of the primary sealing structure is the covering surface;

[0105] S40. Apply solution A and solution B sequentially to the outer edge transition of the photolithographic end of the primary sealing structure, and crosslink solutions A and B at the outer edge transition to form a hydrogel layer.

[0106] HA-BP is obtained using the following method:

[0107] MeHA (methacrylated hyaluronic acid) was dissolved in triethanolamine buffer and stirred overnight to obtain solution No. 1.

[0108] Add 5.5 eq of thiol-BP (thiol-bisphosphate) and 7.5 mM of TCEP (tris(2-carboxyethyl)phosphine hydrochloride) to solution No. 1, stir and react for 48 h (stirring continuously for 48 h) to obtain solution No. 2;

[0109] Solution No. 2 was dialyzed with deionized water for 3 days to obtain solution No. 3;

[0110] Solution No. 3 was frozen overnight at -30°C, then transferred to a lyophilizer and lyophilized to obtain HA-BP, which was then stored at -20°C to obtain HA-BP.

[0111] Alg-RGD-BP is obtained using the following method:

[0112] Dissolve 0.2g of sodium alginate in 20mL of MES (L2-(N-morpholino)ethanesulfonic acid) buffer, stir, and let stand overnight to obtain solution No. 4;

[0113] Add excess Sulfo-NHS (N-hydroxysulfosuccinimide), excess EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide), and excess BP (bisphosphate) to solution No. 4, stir and react for 24 h to obtain solution No. 5;

[0114] Solution No. 5 was dialyzed with deionized water for 3 days to obtain solution No. 6;

[0115] Solution No. 6 was frozen overnight at -30°C, then transferred to a lyophilizer to obtain Alg-RGD-BP, which was stored at -20°C.

[0116] In addition, in step S40, the hydrogel layer can be formed by spin coating or spray coating.

[0117] Spin coating method: Tilt the surface of the plug (photolithography end) and rotate the edge of the plug to immerse it in Alg / HA-BP solution (45° angle, 5 seconds), then pull it up; immerse it in solution B, rotate it 3 times to uniformly crosslink and form hydrogel, then pull it up.

[0118] Spraying method: First spray solution A, then spray solution B, which cross-links to form a hydrogel layer.

[0119] The hydrogel layer has a hardness of 8-10 kPa and a relaxation time of 20 s.

[0120] It should be understood that the above embodiments are merely exemplary and not restrictive. Various obvious or equivalent modifications or substitutions that can be made by those skilled in the art regarding the above details without departing from the basic principles of the present invention will be included within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a nano-blocking structure, characterized in that, Including the following steps: S100, obtain PDO filaments, cylindrical substrates and PLLA flow-blocking membranes; S200. The PDO filaments are woven around the outside of the cylindrical base block and wrapped around the entire cylindrical base block to form a first assembly. S300. The first assembly is immersed in isopropanol for ultrasonic cleaning to obtain the cleaned assembly. S400: Photolithography is performed on at least one end face of the cleaned assembly to obtain a second assembly; S500, Remove the columnar base block from the second assembly to obtain the woven fabric; S600, Heat set the woven fabric to obtain the woven plug; S700, Sew the PLLA flow barrier membrane into the interior of the braided occluder; S800: Apply solution A and solution B to the primary sealing structure obtained in step S700 to form a hydrogel layer at the outer edge transition of the target end face of the primary sealing structure. Solution A is an Alg / HA-BP solution; Solution B is a CaSO4 solution containing YAP / TAZ activating peptide, wherein the concentration of YAP / TAZ activating peptide is 10 μM, and CaSO4 is... 2+ Concentration 80mM; In step S400, the end face of the second assembly undergoing photolithography is the target end face. A first nanotooth of a first preset array is formed on the target end face. The first preset array is a matrix, and the first nanotooth is columnar. The tip area S of the first nanotooth is 8000-250000 nm. 2 The tooth height H is 24-33 μm, and the spacing P between two adjacent first nanotooths is 1-2 μm.

2. The method according to claim 1, characterized in that, The tip of the first nanotooth is hemispherical.

3. The method according to claim 2, characterized in that, The PLLA flow-blocking membrane includes an end membrane. In step S300, the end membrane is immersed in isopropanol for ultrasonic cleaning; In step S400, the cleaned end film is photolithographically etched to obtain a photolithographic end film; In step S700, the photolithographic end film is bonded to the inner side of the target end face, and the photolithographic end face of the photolithographic end film faces outward; In step S400, a second nanotooth of a second preset array is formed on the photolithographic end film. The second preset array is a matrix, and the tip area S of the second nanotooth is 8000-20000 nm. 2 The tooth height is 15-25 μm, and the spacing P between two adjacent second nanotooths is 1-2 μm.

4. The method according to claim 3, characterized in that, The cleaned assembly and the photolithographic end film are collectively referred to as the target body. Step S400 includes... S410. Photoresist is spin-coated onto the target end face of the target body using a spin coater to form a photoresist layer with a thickness of 120-160μm on the target end face. Then, it is baked in an oven at 90℃ for 2 minutes to obtain the target body with photoresist. S420. Expose the target end face of the adhesive-coated target body through a grayscale mask, and then bake it in an oven at 90°C for 3 minutes to obtain the primary product. S430. Immerse the primary product in SU-8 developer for 2 minutes to remove the photoresist in the unexposed areas, rinse with deionized water for 30 seconds, blow dry with nitrogen, and finally cure in a 90°C oven for 10 minutes to obtain the second assembly and photolithographic end film.

5. The method according to claim 4, characterized in that, In step S420, the exposure time is 60 s and the light intensity is 10 mW / cm².

6. The method according to claim 1, characterized in that, Step S800 is as follows: S10, Obtain HA-BP and Alg-RGD-BP; S20. Dissolve Alg-RGD-BP and HA-BP in HEPES to obtain an Alg / HA-BP solution, wherein the mass ratio of Alg-RGD-BP to HA-BP is 4:1 and the mass ratio of Alg-RGD-BP to Alg / HA-BP is 1:

100. S30. Cover the surface of the primary sealing structure with silicone or PTFE, wherein the surface of the primary sealing structure other than the outer edge transition of the photolithographic end is the covering surface. S40. Apply solution A and solution B sequentially to the outer edge transition of the photolithographic end of the primary sealing structure, and crosslink solutions A and B at the outer edge transition to form a hydrogel layer.

7. The method according to claim 6, characterized in that, HA-BP is obtained using the following method: MeHA was dissolved in triethanolamine buffer and stirred overnight to obtain solution number one. Add 5.5 eq of thiol-BP and 7.5 mM of tris(2-carboxyethyl)phosphine hydrochloride to solution No. 1, stir and react for 48 h to obtain solution No. 2; Solution No. 2 was dialyzed with deionized water for 3 days to obtain solution No. 3; Solution No. 3 was frozen overnight at -30°C, then transferred to a lyophilizer for lyophilization to obtain HA-BP, which was then stored at -20°C.

8. The method according to claim 6, characterized in that, Alg-RGD-BP is obtained using the following method: Dissolve 0.2 g of sodium alginate in 20 mL of L2-(N-morpholino)ethanesulfonic acid buffer, stir, and let stand overnight to obtain solution No. 4; Add excess N-hydroxysulfosuccinimide, excess 1-ethyl-(3-dimethylaminopropyl)carbodiimide and excess bisphosphate to solution No. 4, stir and react for 24 h to obtain solution No. 5; Solution No. 5 was dialyzed with deionized water for 3 days to obtain solution No. 6; Solution No. 6 was frozen overnight at -30°C, then transferred to a lyophilizer to obtain Alg-RGD-BP, which was stored at -20°C.

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