Plugging structure convenient for cells to climb and attach

Abstract

The invention relates to a plugging structure convenient for cell creeping attachment, which comprises a plugging body, the plugging body comprises a contraction section and an outer disc section, and the contraction section and the outer disc section are connected with each other; in the unfolded state, the outer diameter of the contraction section is smaller than that of the outer disc section, the outer surface of the outer disc section comprises a circular outer disc face and an annular outer circumferential face, the cross section of the outer circumferential face is semicircular, the outer edge of the outer disc face is connected with the first edge of the outer circumferential face, and the outer edge of the outer disc face is connected with the second edge of the outer circumferential face. The first edge of the peripheral surface is connected with one end of the contraction section, the second edge of the peripheral surface is connected with one end of the contraction section, the first edge and the second edge are circular, the first edge is far away from the contraction section compared with the second edge, and a hydrogel layer is formed on the peripheral surface. And the hydrogel layer is formed on the peripheral surface, so that the creeping attachment of tissue cells is facilitated, and the endothelialization process is accelerated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a convenient cell climbing occlusion structure. BACKGROUND

[0002] Traditional metal occlusion devices have smooth surfaces, and the endothelialization speed is slow (usually 3-6 months are needed). Compared with traditional metal occlusion devices, the endothelialization time of degradable occlusion devices is shortened to a certain extent (usually 1-3 months are needed). However, the heart implant device has an impact on the blood flow dynamics in the heart immediately after implantation, and then has an impact on the formation of thrombus on the surface of the device and the process of endothelialization. In recent years, the exploration of promoting endothelialization mainly has the following several directions: first, the optimization of the structure design of the device reduces the surface area remaining after implantation and is more consistent with the tissue structure around the implant; second, the use of high polymer materials with good biocompatibility and degradability provides a climbing path for cells during the endothelialization stage, and the long-term degradation has no residue; third, the surface modification of the device or the flow blocking film material, such as fluorinated coating (polytetrafluoroethylene) flow blocking film, drug immersion coating or coating with biological activity (heparin, albumin, phosphorylcholine). The current surface modification and coating can reduce platelet activation and inflammatory response to a certain extent, but the existing coating technology (such as heparin coating) has poor durability and is easy to fall off in the early stage of implantation, which cannot provide a sustained coating for promoting endothelialization, and the long-term use effect is still unclear. Moreover, the effect of drug coating on different patients is not completely controllable and is affected by the blood environment in the patient's body. Therefore, there is still a need for a biodegradable heart occlusion device with long-term anticoagulation and more stable endothelialization function in the field. SUMMARY

[0003] Therefore, the present application provides a convenient cell climbing occlusion structure, which forms a hydrogel layer on the outer peripheral surface to facilitate the climbing of tissue cells and accelerate the endothelialization process.

[0004] The technical scheme adopted by the present application is as follows: A convenient cell climbing occlusion structure includes an occlusion body, the occlusion body includes a contraction section and an outer disc section, the contraction section and the outer disc section are connected with each other; in the expanded state, the outer diameter of the contraction section is smaller than the outer diameter of the outer disc section, the outer surface of the outer disc section includes a circular outer disc surface and a circular ring-shaped outer peripheral surface, the cross section of the outer peripheral surface is semicircular, the outer edge of the outer disc surface is connected with the first edge of the outer peripheral surface, the second edge of the outer peripheral surface is connected with one end of the contraction section, the first edge and the second edge are both circular, the first edge is farther away from the contraction section than the second edge, and a hydrogel layer is formed on the outer peripheral surface.

[0005] Preferably, the outer peripheral surface includes a first area and a second area that are connected to each other, the first area and the second area are both annular, the first area and the second area completely cover the outer peripheral surface, the first area is connected to the first edge, the second area is connected to the second edge, the cross-section of the first area is arc-shaped, and its curvature is 120°-135°; a hydrogel layer is formed on the first area, and no hydrogel layer is formed on the second area.

[0006] Preferably, the first region forms a hydrogel layer by the following method, Applying solution A and solution B respectively on the first area to form a hydrogel layer on the first area; Solution A is Alg / HA-BP solution; Solution B is CaSO4 solution with YAP / TAZ activating peptide added, where the concentration of YAP / TAZ activating peptide is 10 μM and Ca 2+ Concentration 80mM.

[0007] Preferably, the Alg / HA-BP solution is obtained by the following method: S10, obtaining 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.

[0008] Preferably, the method of forming the hydrogel layer on the first region is: S30, covering the covering surface of the blocking body with silicone or PTFE, wherein the covering surface is all surfaces of the blocking body except the first area; S40, applying solution A and solution B sequentially on the first area, and cross-linking solutions A and B to form a hydrogel layer.

[0009] Preferably, HA-BP is obtained by the following method: Dissolve MeHA in triethanolamine buffer and stir overnight to obtain solution No. 1; 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 hours to obtain solution No. 2; Solution No. 2 was dialyzed against deionized water for 3 days to obtain solution No. 3; Solution No. 3 was frozen at -30°C overnight, then transferred to a freeze dryer for freeze drying to obtain HA-BP, which was then stored at -20°C.

[0010] Preferably, the Alg-RGD-BP is obtained by the following method: Dissolve 0.2 g of sodium alginate in 20 mL of L2-(N-morpholino)ethanesulfonic acid buffer, stir overnight to obtain solution No. 4; Add excess N-hydroxysulfosuccinimide, excess 1-ethyl-(3-dimethylaminopropyl) carbonyldiimide and excess bisphosphate to solution No. 4, stir and react for 24 h to obtain solution No. 5; Dialyze solution No. 5 through deionized water for 3 days to obtain solution No. 6; Freeze solution No. 6 at -30℃ overnight, then transfer it to a freeze dryer to obtain Alg-RGD-BP, and store it at -20℃.

[0011] Advantages of the present application: The water gel layer is formed on the outer circumferential surface of the occlusion body, in actual application, the contraction section of the occlusion structure is clamped at the target position, the outer disc section closes the target position from the outside, most of the outer circumferential surface and the entire outer disc surface of the outer disc section are in contact with blood, the water gel layer is convenient for tissue cells to climb, so that the tissue cells can climb along the water gel layer to the first edge, so that the tissue cells can easily cover the entire outer circumferential surface; in actual use, from the outside to the inside in the radial direction, the outer disc surface gradually recesses to one side of the contraction section, which reduces the difficulty of tissue cells climbing on the outer disc surface, so that the tissue cells can easily cover the entire occlusion structure, thereby achieving the purpose of accelerating the endothelialization process. BRIEF DESCRIPTION OF DRAWINGS

[0012] The above and other objects, features and advantages of the present application will become more apparent from the following description of embodiments of the present application taken in conjunction with the accompanying drawings, in which: Figure 1 is a structural schematic diagram of the occlusion structure; Figure 2 is a structural schematic diagram of the occlusion structure; Figure 1 is a sectional view of the occlusion structure in FIG. 1; Figure 3 is a comparison of endothelial cell proliferation before and after dynamic water gel coating.

[0013] In the figure: 1, outer disc section; 2, contraction section; 11, outer disc surface; 12, outer circumferential surface. DETAILED DESCRIPTION

[0014] The present application is described below based on examples, but the present application is not limited to only these examples. In the following detailed description of the present application, some specific details are described in detail in order to avoid obscuring the essence of the present application, and well-known methods, processes, procedures, elements are not described in detail.

[0015] Furthermore, persons of ordinary skill in the art will appreciate that the figures provided herein are for illustration purposes only and are not necessarily drawn to scale.

[0016] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include," "comprising," and similar words should be construed in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to."

[0017] In the description of the present invention, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0018] See also Figures 1-3 The present invention provides a blocking structure that facilitates cell attachment, including a blocking body, wherein the blocking body includes a contraction section 2 and an outer disc section 1, and the contraction section 2 is connected to the outer disc section 1; in the expanded state, the outer diameter of the contraction section 2 is smaller than the outer diameter of the outer disc section 1, and the outer surface of the outer disc section 1 includes a circular outer disc surface 11 and an annular outer peripheral surface 12, the cross-section of the outer peripheral surface 12 is semicircular, the outer edge of the outer disc surface 11 is connected to the first edge of the outer peripheral surface 12, and the second edge of the outer peripheral surface 12 is connected to one end of the contraction section 2, the first edge and the second edge are both circular, the first edge is farther away from the contraction section 2 than the second edge, and a hydrogel layer is formed on the outer peripheral surface 12.

[0019] In the present invention, the occluding structure can be a left atrial appendage occluder or an atrial septum / ventricular septum occluder. In the embodiment in which the occluding structure is a left atrial appendage occluder, the number of contraction segments 2 and the number of outer disc segments 1 are each one; in the embodiment in which the occluding structure is an atrial septum / ventricular septum occluder, the number of contraction segments 2 is one, the number of outer disc segments 1 is two, and the two ends of the contraction segment 2 are respectively connected to an outer disc segment 1, so that the overall occluding structure is dumbbell-shaped.

[0020] The occlusion structure is described by taking a left atrial appendage occluder as an example.

[0021] When the occlusion structure is implanted into the left atrial appendage, the contraction section 2 is inserted into the left atrial appendage, and the radial size of the outer disc section 1 is larger than the opening of the left atrial appendage, so that the outer disc section 1 covers the entire opening of the left atrial appendage, and most of the outer surface of the outer disc section 1 is not in direct contact with the left atrial appendage, only part of the outer peripheral surface 12 near the contraction section 2 is in contact with the tissue near the left atrial appendage, so that the water gel layer is arranged on the outer peripheral surface 12, which reduces the difficulty of cell climbing, so that the tissue cells can climb along the outer peripheral surface 12 to the outer disc surface 11, and the tissue cells can easily cover the entire outer peripheral surface 12; in actual use, from the outside to the inside in the radial direction, the outer disc surface 11 gradually recedes to one side of the contraction section 2 (that is, the center of the outer disc surface 11 is inwardly contracted), which reduces the difficulty of cell climbing on the outer disc surface 11, so that the tissue cells can easily cover the entire occlusion structure, thereby achieving the purpose of accelerating the endothelialization process. Figure 3 The fluorescence image (blue cell nucleus, red actin fiber) of the endothelial cells measured by the confocal microscope (model: Carl Zeiss LSM880, Germany) can clearly show that the proliferation speed of the endothelial cells is increased by 3 times.

[0022] The occlusion body includes a woven occluder woven by PDO (poly-p-dioxanone) wires and a PLLA (poly-L-lactic acid) flow blocking film sewn inside the woven occluder. As described above, the tissue cells will climb the entire outer surface of the outer disc section 1, so that the tissue cells will naturally close the opening of the left atrial appendage. At the same time, the PDO wires and the PLLA flow blocking film also have degradable properties, so that the cell tissue will eventually close the left atrial appendage, thereby achieving the purpose of the operation.

[0023] The outer peripheral surface 12 includes a first region and a second region connected to each other, both the first region and the second region are annular, the first region and the second region completely cover the outer peripheral surface 12, the first region is connected to the first edge, the second region is connected to the second edge, the cross section of the first region is in the shape of a circular arc with an arc degree of 120°-135°; the water gel layer is formed on the first region, and no water gel layer is formed on the second region.

[0024] The first region and the second region jointly constitute the outer peripheral surface 12, the cross section of the outer peripheral surface 12 has an arc degree of 180°, the arc degree of the first region is 120°-135°, so that the arc degree of the second region is 60°-45°. In actual application, the first region is not in direct contact with the left atrial appendage, and the second region is in direct contact with the left atrial appendage. No water gel layer is formed on the second region, so as to avoid the setting of the water gel layer, reduce the friction between the occlusion structure and the left atrial appendage, and avoid the friction between the left atrial appendage being too small to cause falling off.

[0025] The first region forms the water gel layer by the following method.

[0026] A solution and B solution are respectively applied on the first region, so that a hydrogel layer is formed on the first region; The A solution is an Alg / HA-BP (alginate and bisphosphonate-modified hyaluronic acid) solution; the B solution is a CaSO4 (calcium sulfate) solution added with YAP / TAZ activating peptide, wherein the concentration of the YAP / TAZ activating peptide is 10 μM, and the concentration of CaSO4 is 80 mM. 2+ The concentration is 80 mM.

[0027] YAP / TAZ is YAP (Yes-associated protein): Yes-associated protein (or "YAP transcriptional regulatory protein"); TAZ (Transcriptional coactivator with PDZ-binding motif): transcriptional coactivator TAZ (transcriptional coactivator with PDZ-binding motif).

[0028] The Alg / HA-BP solution is obtained by the following method: S10, HA-BP (bisphosphonate-modified hyaluronic acid) and Alg-RGD-BP are obtained.

[0029] The Alg-RGD-BP is sodium alginate modified by bisphosphonate (BP) and a cell adhesion-promoting short peptide (RGD) composed of arginine (R), glycine (G), and aspartic acid (D).

[0030] S20, Alg-RGD-BP and HA-BP are dissolved in HEPES (4-hydroxyethylpiperazine ethanesulfonic acid solution) 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] The method for forming a hydrogel layer on the first region is: S30, the covering surface of the blocking body is covered by silica gel or PTFE (polytetrafluoroethylene), which is all the surface of the blocking body except the first region.

[0032] S40, A solution and B solution are sequentially applied on the first region, and the A and B solutions are crosslinked to form a hydrogel layer.

[0033] The HA-BP is obtained by the following method: MeHA (methyl acrylate hyaluronic acid) is dissolved in triethanolamine buffer and stirred overnight to obtain a first solution.

[0034] Add 5.5 eq of thiol-BP (thiol-bisphosphate) and 7.5 mM of TCEP (tris(2-carboxyethyl)phosphine hydrochloride) to the No. 1 solution, stir, and react for 48 h (stir for 48 h), to obtain a No. 2 solution.

[0035] Dialyze the No. 2 solution with deionized water for 3 days to obtain a No. 3 solution.

[0036] Freeze the No. 3 solution at -30°C overnight, then transfer it to a freeze dryer to obtain HA-BP, and store it at -20°C.

[0037] Alg-RGD-BP is obtained by the following method: Dissolve 0.2 g of sodium alginate in 20 mL of MES (L2-(N-morpholino)ethanesulfonic acid) buffer, stir, and react overnight to obtain a No. 4 solution.

[0038] Add excess Sulfo-NHS (N-hydroxysulfosuccinimide), excess EDC (1-ethyl-(3-dimethylaminopropyl) carbodiimide), and excess BP (bisphosphate) to the No. 4 solution, stir, and react for 24 h to obtain a No. 5 solution.

[0039] Dialyze the No. 5 solution with deionized water for 3 days to obtain a No. 6 solution.

[0040] Freeze the No. 6 solution at -30°C overnight, then transfer it to a freeze dryer to obtain Alg-RGD-BP, and store it at -20°C.

[0041] In addition, in step S40, the hydrogel layer can be formed by a spin coating method or a spraying method.

[0042] Spin coating method: tilt the outer disc surface 11 of the occluder, immerse the first edge into the Alg / HA-BP solution (45° angle, 5 seconds), and pull up; immerse it into the B solution, rotate for 3 turns to uniformly crosslink and form a hydrogel, and pull up.

[0043] Spraying method: spray the A solution on the first area first, then spray the B solution, and crosslink to form a hydrogel layer.

[0044] The hardness of the hydrogel layer is 8-10 kPa, and the relaxation time is 20 s.

[0045] It should be understood that the above embodiments are only exemplary and not limiting, and various obvious or equivalent modifications or replacements can be made to the above details by those skilled in the art without departing from the basic principles of the present application, which will be included in the scope of the claims of the present application.

Claims

1. A blocking structure that facilitates cell attachment, characterized in that: The invention comprises a sealing body, wherein the sealing body comprises a contraction section and an outer disc section, and the contraction section and the outer disc section are connected to each other; in the expanded state, the outer diameter of the contraction section is smaller than the outer diameter of the outer disc section, the outer surface of the outer disc section comprises a circular outer disc surface and an annular outer peripheral surface, the cross-section of the outer peripheral surface is semicircular, the outer edge of the outer disc surface is connected to the first edge of the outer peripheral surface, the second edge of the outer peripheral surface is connected to one end of the contraction section, the first edge and the second edge are both circular, the first edge is farther away from the contraction section than the second edge, and a hydrogel layer is formed on the outer peripheral surface.

2. The blocking structure for facilitating cell attachment according to claim 1, characterized in that: The outer peripheral surface includes a first area and a second area that are interconnected, the first area and the second area are both annular, the first area and the second area completely cover the outer peripheral surface, the first area is connected to the first edge, the second area is connected to the second edge, the cross-section of the first area is arc-shaped, and its curvature is 120°-135°; a hydrogel layer is formed on the first area, and no hydrogel layer is formed on the second area.

3. The blocking structure for facilitating cell attachment according to claim 2, characterized in that: The first region forms a hydrogel layer by the following method: Applying solution A and solution B respectively on the first area to form a hydrogel layer on the first area; Solution A is Alg / HA-BP solution; Solution B is CaSO4 solution with YAP / TAZ activating peptide added, where the concentration of YAP / TAZ activating peptide is 10 μM and Ca 2+ Concentration 80mM.

4. The blocking structure for facilitating cell attachment according to claim 3, characterized in that: The Alg / HA-BP solution was obtained by the following method: S10, obtaining 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.

5. The blocking structure for facilitating cell attachment according to claim 4, characterized in that: The method of forming the hydrogel layer on the first area is: S30, covering the covering surface of the blocking body with silicone or PTFE, wherein the covering surface is all surfaces of the blocking body except the first area; S40, applying solution A and solution B sequentially on the first area, and cross-linking solutions A and B to form a hydrogel layer.

6. The blocking structure for facilitating cell attachment according to claim 4, characterized in that: The HA-BP is obtained using the following method: Dissolve MeHA in triethanolamine buffer and stir overnight to obtain solution No. 1; 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 hours to obtain solution No. 2; Solution No. 2 was dialyzed against deionized water for 3 days to obtain solution No. 3; Solution No. 3 was frozen at -30°C overnight, then transferred to a freeze dryer for freeze drying to obtain HA-BP, which was then stored at -20°C.

7. The blocking structure for facilitating cell attachment according to claim 6, characterized in that: Alg-RGD-BP was obtained using the following method: Dissolve 0.2 g of sodium alginate in 20 mL of L2-(N-morpholino)ethanesulfonic acid buffer, stir, and store 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 hours to obtain solution No. 5; Solution No. 5 was dialyzed against deionized water for 3 days to obtain Solution No. 6; Solution No. 6 was frozen at -30°C overnight, then transferred to a freeze dryer for freeze drying to obtain Alg-RGD-BP, which was then stored at -20°C.

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