A dura repair patch having suture guide structures and methods of making the same

Abstract

The application provides a dura mater repair patch with a suture guiding structure and a preparation method thereof, and belongs to the technical field of biomedical materials. The patch comprises at least three layers: an A layer facing the brain, a C layer facing the skull, and a B layer buffer layer arranged between the two. The C layer is provided with a suture guiding blind hole extending inward from the surface and terminating at the B layer, and the B layer is provided with a thickened area at the area corresponding to the blind hole. The structure can guide the suture path, reduce stress concentration at the suture, and at the same time, the B layer can realize zero leakage by sealing the hole bottom, and the thickened area can further improve the bearing capacity. The patch has good suture guiding property, tear resistance and clinical cutting adaptability, and is suitable for the field of dura mater defect repair.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and in particular to a dura mater repair patch with a suture guidance structure and its preparation method. Background Technology

[0002] The dura mater is an important connective tissue structure covering the surface of the brain and spinal cord. Its main function is to protect the central nervous system and maintain a closed environment for cerebrospinal fluid circulation. During craniocerebral surgery, traumatic brain injury, or tumor resection, the dura mater often suffers defects or requires partial resection. Therefore, it needs to be repaired with artificial materials to restore the integrity of the dura mater and prevent cerebrospinal fluid leakage. An ideal dura mater repair material should meet the following requirements: (1) effectively block cerebrospinal fluid leakage; (2) allow dura mater tissue regeneration; (3) be easy to suture and fix, and the suture site is not easy to tear; (4) adapt to intracranial pressure fluctuations.

[0003] Currently, the main materials used clinically for dura mater repair include autologous tissue, allogeneic materials, and synthetic materials. Autologous tissues, such as fascia or periosteum, have good biocompatibility, but suffer from limited availability and significant invasiveness during harvesting. Allogeneic or xenogeneic materials may pose risks of immune reactions and disease transmission. Biodegradable synthetic materials are gradually becoming an important research direction for dura mater repair. In actual surgical procedures, the artificial dura mater usually needs to be sutured and fixed to the surrounding tissues. However, due to the thinness or dense structure of the repair material, local stress concentration can easily occur during suturing, leading to tearing or damage at the suture sites. Furthermore, the suture location often depends on the surgeon's experience, and uneven suture placement can further increase local stress concentration on the material.

[0004] To improve the mechanical properties of materials, some existing technologies increase overall strength by increasing material thickness or employing multi-layered structures. However, these structures are often formed simply by stacking layers, offering limited improvement to the stress concentration problem in localized suture areas. When sutures pass through the material, tears or crack propagation may still occur around the sutures, affecting the repair outcome. Furthermore, in some multi-layered materials, the layers are typically rigidly bonded or directly stacked, lacking an intermediate layer to effectively buffer stress. When the material is subjected to tensile or shear forces during suturing or tissue movement, the layers cannot effectively disperse stress, potentially leading to localized structural failure.

[0005] Therefore, the existing dura mater repair materials still have the following problems in practical applications: (1) Stress concentration is easily generated at the suture line during the suturing and fixation process, which leads to tearing or damage of the material; (2) The suture position lacks a clear guiding structure, and uneven suture position may further aggravate the uneven local stress of the material; (3) Most of the existing multilayer structure materials are simple stacked structures, and there is no effective buffer structure between each layer, making it difficult to effectively disperse stress when subjected to tension or shear.

[0006] Therefore, it is necessary to provide a new dura mater patch structure that, through a reasonable layered structure design and suture guidance structure setting, reduces stress concentration at the suture site and improves the tear resistance of the material during the suturing process, thereby enhancing the safety and reliability of the material in dura mater repair. Summary of the Invention

[0007] In view of this, the present invention provides a dura mater repair patch with a suture guidance structure, the dura mater repair patch comprising at least three layers, namely layer A, layer B and layer C; layer A facing the brain, layer C facing the skull, and layer B disposed between layer A and layer C to form an interlayer buffer layer.

[0008] Furthermore, a suture guide hole is provided on the C layer, which extends inward from the C layer to form a blind hole structure and terminates in the B layer; the B layer has a thickened area in the region corresponding to the blind hole structure of the C layer, and a relatively thinned area in the region away from the blind hole structure.

[0009] Furthermore, the thickness of layer A is 30-50 μm.

[0010] Furthermore, the thickness of the thickened area of ​​the B layer is 80-150 μm, and the thickness of other areas of the B layer is 50-80 μm.

[0011] Furthermore, the thickness of the C layer is 60-100 μm.

[0012] Furthermore, the B-layer buffer structure is selected from any one of porous polymer membrane structure, elastic polymer coating structure, and loose fiber layer structure.

[0013] Furthermore, the suture guide hole includes either a continuous guide type or an intermittent guide type.

[0014] Furthermore, the continuous guide type has a hole center spacing of 1.5-3mm, and guides needles one by one.

[0015] Furthermore, in the spaced-guide type, the center-to-center spacing of the holes is 4-8mm, and a guide point is set every 2-3 needles.

[0016] Furthermore, the diameter of the suture guide hole is 0.3-0.8 mm.

[0017] Furthermore, the suture guide hole array includes at least two hole areas distributed radially along the patch, wherein the center of the first hole area is 2-4 mm from the edge; and the second hole area is located inside the first hole area, with the center of the hole 5-10 mm from the edge.

[0018] Furthermore, the arrangement of the suture guide hole array includes any one of the following: single-row linear arrangement, double-row linear arrangement, double-row staggered arrangement, ring or elliptical array.

[0019] Furthermore, layers A, B, and C are all made of biodegradable polymer materials.

[0020] Furthermore, the biodegradable polymer material is selected from at least one of aliphatic polyester materials and natural polymer materials;

[0021] Furthermore, the aliphatic polyester material includes blends of any one or more of polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), polylactic acid-glycolic acid copolymer (PLGA), and polylactic acid-caprolactone copolymer (PLCL).

[0022] Furthermore, the natural polymeric material includes any one or a blend of collagen, gelatin, chitosan, or hyaluronic acid.

[0023] The present invention also provides a method for preparing the dura mater repair patch with the suture guidance structure, comprising the following steps:

[0024] (1) Using biodegradable polymer materials as raw materials, prepare spinning solution, perform electrospinning, and prepare A-layer fiber membrane;

[0025] (2) Porous polymer membrane, using biodegradable polymer as raw material, B layer fiber membrane is prepared by non-solvent induced phase separation method, and thickened area is formed in the region corresponding to the blind pore structure of C layer by local stacking method;

[0026] (3) Prepare spinning solution using aliphatic polyester materials or a mixture of aliphatic polyester materials and natural polymer materials as raw materials, and perform electrospinning to prepare C-layer fiber membrane;

[0027] (4) A suture guide hole is fabricated on the C-layer fiber membrane;

[0028] (5) Layers A, B and C are laminated to obtain a dura mater repair patch with a suture guidance structure.

[0029] Furthermore, an elastic polymer coating is used to replace the porous polymer membrane in step (2); the preparation method of the elastic polymer coating includes: using a biodegradable polymer as raw material, curing it after spraying or dipping, and forming a local thickening area by selective coating in the area corresponding to the blind hole structure of layer C.

[0030] Furthermore, a loose fiber layer is used to replace the porous polymer membrane in step (2); the method for preparing the loose fiber layer includes: using a biodegradable polymer as raw material, preparing a loose fiber layer through electrospinning process, and selectively compacting the area during hot pressing process to maintain a larger thickness in the area corresponding to the blind pore structure, thus forming a relatively thickened area.

[0031] Furthermore, the loose fiber layer is prepared using a low-speed (speed < 300 rpm) electrospinning process.

[0032] Furthermore, the processing and stitching guide hole method described in step (4) includes any one of micro-needle punching, laser micromachining, and mold pre-made hole.

[0033] Furthermore, the interlayer composite process in step (5) includes either hot pressing or electrospinning.

[0034] The present invention also provides the application of the dura mater repair patch in the field of dura mater defect repair.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) Reduce stress concentration at the seam

[0037] This invention provides a suture guide hole that penetrates the C-layer structure in the medical repair membrane, allowing the suture to pass through the material at a preset position. This reduces local stress concentration caused by uneven suture placement and improves the stability of the material during the suture fixation process.

[0038] (2) Balancing guidance with operational freedom

[0039] By setting up a non-continuous blind hole array, rigid restrictions on the suture path are avoided, improving the surgeon's operational flexibility and adaptability.

[0040] (3) The buffer layer structure can effectively disperse stress.

[0041] This invention incorporates a buffer structure, layer B, between layers A and C. The suture guide hole does not penetrate layer B, and layer B forms a continuous thickened gasket around the hole. When the material is subjected to tensile or shear forces during suturing or tissue movement, the suture tension is first absorbed by the elastic deformation of layer B, rather than directly acting on the fibers of layers A and C. This reduces the risk of local structural damage to the material and improves the overall tear resistance.

[0042] (4) Gradient thickness matching stress distribution

[0043] The gradient design of different thicknesses in layer B matches the actual mechanical environment of high stress in the suture area and relatively low stress in other areas during dura mater repair, thus optimizing material utilization.

[0044] (5) To achieve sewing guidance under different cutting conditions

[0045] The multi-level perforation structure enables stable suture guidance of the patch under different cutting conditions, thereby improving clinical adaptability.

[0046] (6) Multi-layer structure improves material reliability

[0047] Through the multi-layer structure design of layers A, B, and C, the material maintains the necessary mechanical properties while possessing certain flexibility and cushioning properties. At the same time, layers A and B seal the bottom of the guide hole, achieving zero leakage, thereby improving the safety and reliability of the material in actual surgical applications. Attached Figure Description

[0048] Figure 1 These are the suture performance test results of the dura mater repair patch described in Embodiment 1 and Comparative Examples 1-5 of the present invention.

[0049] Figure 2 These are the tensile strength test results of the dura mater repair patches described in Embodiment 1 and Comparative Examples 1-5 of the present invention.

[0050] Figure 3 The graph shows the test results of the fracture elongation of the dura mater repair patch described in Embodiment 1 and Comparative Examples 1-5 of the present invention.

[0051] Figure 4 This is a schematic diagram of the dura mater repair patch structure of the present invention.

[0052] Figure 5 This is a schematic diagram of the porous polymer membrane structure of the present invention.

[0053] Figure 6 This is a schematic diagram of the elastic coating layer structure of the present invention.

[0054] Figure 7 This is a schematic diagram of the loose fiber layer structure of the present invention.

[0055] Note: Figure 4 In the diagram, 1 represents the guide hole for suturing in layer C, 2 represents layer C, 3 represents the thickened area in layer B, 4 represents layer B, and 5 represents layer A.

[0056] Figure 5 In the figure, 1 represents the porous polymer membrane of layer B.

[0057] Figure 6 In the middle, 1 represents the B layer elastic coating layer.

[0058] Figure 7 In the middle, 1 represents the loose fibrous layer B.

[0059] Figure 8 This is a schematic diagram of a single-row linear arrangement of the present invention.

[0060] Figure 9 This is a schematic diagram of the double-row linear arrangement of the present invention.

[0061] Figure 10 This is a schematic diagram of the double-row staggered arrangement of the present invention.

[0062] Figure 11 This is a schematic diagram of the ring array of the present invention.

[0063] Figure 12 This is a schematic diagram of the elliptical array of the present invention.

[0064] Figure 13 This is a schematic diagram of the single-row linear multi-level pore region structure of the present invention.

[0065] Figure 14 This is a schematic diagram of the ring array multi-level hole region structure of the present invention. Detailed Implementation

[0066] The present invention provides a dura mater repair patch with a suture guidance structure, the dura mater repair patch comprising at least three layers, namely layer A, layer B and layer C; layer A and layer C are supporting structural layers, layer A facing the brain and layer C facing the skull, and layer B is disposed between layer A and layer C to form an interlayer buffer layer.

[0067] In some embodiments of the present invention, a suture guide hole is provided on the C layer. The suture guide hole extends inward from the C layer to form a blind hole structure and terminates at the B layer. The reason for this design is that it provides the best surgical visibility, allowing the doctor to directly see the hole array during operation and suture according to the hole positions; it does not affect the sealing performance, as the holes do not penetrate the B and A layers, and cerebrospinal fluid will not leak through the holes; it also has a more obvious tear resistance effect, as the holes are pre-fabricated, stress is concentrated at the edge of the holes, and crack propagation stops at the holes, controlling the tear propagation path, similar to the "crack blocking design" in engineering materials.

[0068] The B layer has a thickened area corresponding to the blind hole structure in the C layer to improve the load-bearing capacity of the suture area; and a relatively thinned area in the area away from the blind hole structure to ensure overall flexibility. Therefore, the thickness of the thickened area of ​​the B layer is 80-150 μm, preferably 100 μm, and the thickness of other areas is 50-80 μm, preferably 60 μm.

[0069] In some embodiments of the present invention, the suture guide hole is located at the edge of layer C, the hole is located in the thickened area of ​​layer B, the blind hole only penetrates layer C and terminates in layer B, and does not penetrate layer A. Layer A and layer B seal the bottom of the hole to achieve zero leakage.

[0070] Through the above innovative combination, this invention achieves synergistic optimization of dura mater repair patches in terms of preventing leakage and suture tearing.

[0071] In some embodiments of the present invention, layer A is a dense barrier layer facing the brain tissue, which must have a certain degree of adhesion; excessive thickness will reduce compliance and affect adhesion. The thickness of layer A is 30-50 μm, preferably 40 μm.

[0072] In some embodiments of the present invention, the B-layer buffer structure (stress buffer layer) is selected from any one of porous polymer membrane structure, elastic polymer coating structure, and loose fiber layer structure, and is used to dissipate stitching stress, buffer the difference in modulus between layers, and seal the bottom of blind holes to prevent leakage. Specifically, the porous polymer membrane structure provides buffering through pore compression; the elastic polymer coating structure absorbs stress through elastic deformation of the material; and the loose fiber layer structure dissipates energy through fiber slippage and pore compression.

[0073] In some embodiments of the present invention, the C layer is a tissue integration layer facing the skull and has a blind hole structure. During use, the C layer directly bears the puncture of the suture needle and localized concentrated stress, therefore it needs to have a certain thickness to avoid tearing. Therefore, the thickness of the C layer is set to 60-100 μm, preferably 80 μm.

[0074] In some embodiments of the present invention, the suture guide hole includes either a continuous guide type or an intermittent guide type.

[0075] In some embodiments of the present invention, the continuous guide type has a hole center spacing of 1.5-3 mm, and guides needles one by one.

[0076] In some embodiments of the present invention, the spaced guide type has a hole center spacing of 4-8 mm, preferably 5-7 mm, and a guide point is provided for every 2-3 needles.

[0077] In this invention, the spaced guiding design is to set a guiding point every 2-3 stitches during clinical suturing. This structural design provides the surgeon with a reference positioning point during suturing, allowing the surgeon to perform 1-2 stitches of free suturing operation space between adjacent blind holes, thereby improving operational flexibility while ensuring suturing uniformity.

[0078] In some embodiments of the present invention, the diameter of the suture guide hole is 0.3-0.8 mm.

[0079] In some embodiments of the present invention, the suture guide hole array includes at least two hole areas (multi-level hole area structure) distributed radially along the patch. The first hole area, located near the edge of the patch with a hole center 2-4 mm from the edge, functions to provide direct suture path guidance when the patch edge is not trimmed. The second hole area, located inside the first hole area with a hole center 5-10 mm from the edge, serves as a backup guide structure after the patch edge has been trimmed, ensuring the suture guidance function remains functional. A third hole area (optional) is located further inward to further improve adaptability under extreme trimming conditions.

[0080] In this invention, the multi-level hole area structure ensures that the patch can provide stable suture guidance under different cutting conditions. Even if the outer hole area is partially or completely removed, the inner hole area can still be retained, thereby maintaining the suture guidance function and improving its clinical applicability and operational flexibility.

[0081] In some embodiments of the present invention, the arrangement of the suture guide hole array includes any one of the following: single-row linear arrangement, double-row linear arrangement, double-row staggered arrangement, annular or elliptical array. Preferably, a double-row staggered arrangement can better reduce the risk of crack propagation along the hole array direction. More preferably, the spacing of the double-row linear arrangement is 1.5-2.5 mm, and most preferably 2 mm.

[0082] In some embodiments of the present invention, the dura mater repair patch is a sheet-like structure, and its shape can be set to any one or a combination of the following according to clinical needs: regular shape or irregular shape; the regular shape includes, but is not limited to, any one of rectangle, square, circle, and ellipse; preferably, the dura mater repair patch is a regular shape, which is convenient for cutting and use according to the shape of the defect during surgery.

[0083] In some embodiments of the present invention, layers A, B and C are all made of biodegradable polymer materials.

[0084] In some embodiments of the present invention, the biodegradable polymer material is selected from at least one of aliphatic polyester materials and natural polymer materials.

[0085] In some embodiments of the present invention, the aliphatic polyester material includes blends of any one or more of polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), polylactic acid-glycolic acid copolymer (PLGA), and polylactic acid-caprolactone copolymer (PLCL).

[0086] In some embodiments of the present invention, the natural polymer material includes any one or a blend of collagen, gelatin, chitosan or hyaluronic acid.

[0087] The present invention also provides a method for preparing the dura mater repair patch with the suture guidance structure, comprising the following steps:

[0088] (1) Using biodegradable polymer materials as raw materials, prepare spinning solution, perform electrospinning, and prepare A-layer fiber membrane;

[0089] (2) Porous polymer membrane, using biodegradable polymer as raw material, B layer fiber membrane is prepared by non-solvent induced phase separation method, and thickened area is formed in the region corresponding to the blind pore structure of C layer by local stacking method;

[0090] (3) Prepare spinning solution using aliphatic polyester materials or a mixture of aliphatic polyester materials and natural polymer materials as raw materials, and perform electrospinning to prepare C-layer fiber membrane;

[0091] (4) A suture guide hole is fabricated on the C-layer fiber membrane;

[0092] (5) Layers A, B and C are laminated to obtain a dura mater repair patch with a suture guidance structure.

[0093] In some embodiments of the present invention, an elastic polymer coating is used to replace the porous polymer membrane in step (2); the preparation method of the elastic polymer coating includes: using a biodegradable polymer as raw material, curing it after spraying or dipping, and forming a local thickening area by selective coating in the area corresponding to the blind hole structure of layer C.

[0094] In some embodiments of the present invention, a loose fiber layer is used to replace the porous polymer membrane in step (2); the method for preparing the loose fiber layer includes: using a biodegradable polymer as raw material, preparing a loose fiber layer by electrospinning process, and selectively compacting the region during hot pressing process to maintain a larger thickness in the region corresponding to the blind pore structure, thereby forming a relatively thickened region.

[0095] In some embodiments of the present invention, the loose fiber layer is prepared using a low-speed (speed < 300 rpm) electrospinning process.

[0096] In some embodiments of the present invention, the aliphatic polyester material or the mixture of aliphatic polyester material and natural polymer material mentioned in step (3) refers to the raw material being either "aliphatic polyester material" or "a mixture of aliphatic polyester material and natural polymer material".

[0097] In some embodiments of the present invention, the method of processing the stitching guide hole in step (4) includes any one of micro-needle punching, laser micromachining, and mold pre-made hole.

[0098] In some embodiments of the present invention, the interlayer lamination in step (5) includes either hot pressing or electrospinning. In the present invention, during hot pressing, anti-sticking films, such as PTFE films or Kapton films, must be used on both sides of layers A and C; otherwise, the materials will stick to the hot pressing plate.

[0099] The present invention also provides the application of the dura mater repair patch in the field of dura mater defect repair.

[0100] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0101] Unless otherwise specified, the test methods or experimental methods described in the following examples are all conventional methods; unless otherwise specified, the raw materials and additives are obtained from conventional commercial sources or prepared by conventional methods.

[0102] Example 1

[0103] (PLCL system + collagen + loose fiber layer + UV laser perforation)

[0104] A method for preparing a dura mater repair patch with a suture guiding structure, the specific steps of which are as follows:

[0105] (1) Dissolve PLCL in hexafluoroisopropanol to prepare a spinning solution with a concentration of 14wt%, and perform electrospinning to prepare an A-layer fiber membrane with a thickness of 40μm.

[0106] The electrospinning parameters are as follows: positive voltage 14kV, negative voltage -2kV, liquid pushing speed 2.4mL / h, receiving distance 17cm, roller speed 500rpm, and spinning time 45min.

[0107] (2) Dissolve PLCL in hexafluoroisopropanol to prepare a spinning solution with a concentration of 12wt% and prepare a B-layer fiber membrane;

[0108] Electrospinning parameters: positive voltage 15kV, negative voltage -2kV, liquid pushing speed 4 mL / h, receiving distance 18cm, roller speed 200rpm, spinning time 45min, initial thickness 150μm; selective compaction was performed using a zoned hot-pressing mold, with a hot-pressing temperature of 105℃ (below the melting point), a pressure of 0.2MPa for the thickened zone to 100μm, and a pressure of 0.8MPa for the other zones to 60μm, for 60s.

[0109] (3) PLCL and collagen were added to hexafluoroisopropanol at a mass ratio of PLCL:collagen = 8:2 to prepare a spinning solution with a concentration of 12wt%, and electrospinning was performed to prepare a C-layer fiber membrane with a thickness of 80μm.

[0110] The electrospinning parameters are: positive voltage 15kV, negative voltage -2kV, liquid pushing speed 4mL / h, receiving distance 16cm, roller speed 400rpm, and spinning time 50min.

[0111] (4) The suture guide hole is processed by ultraviolet laser drilling on the C layer fiber membrane. The suture guide hole penetrates the thickness of the C layer and has a diameter of 0.4 mm. The suture guide hole array is arranged in a double row staggered arrangement, and only the first hole area is set. The center distance of the outer hole is 3 mm from the edge of the patch, and the spacing between the two rows is 2 mm.

[0112] The ultraviolet laser drilling method involves fixing the C-layer fiber membrane onto a laser processing platform, controlling the laser path via computer to perform point scanning within a set area, using a pulsed laser frequency of 50kHz, a laser power of 5.5W, and an energy density of 0.4J / mm². 2 The single-hole scanning time is 0.15s, and the laser spot diameter is 0.15mm.

[0113] (5) Layers A, B and C are laminated to obtain a dura mater repair patch with a suture guidance structure.

[0114] Layers A, B, and C were sequentially laid flat on a flatbed hot press. A PTFE anti-adhesion membrane was used on both sides of layers A and C. The temperature was 110°C, which is below the polymer melting point but above the glass transition temperature, causing segmental diffusion at the interface rather than complete melting. This ensured the interlayer bonding strength while maintaining the stability of the porous structure. The pressure was 1.8 MPa, and the time was 90 seconds. After hot pressing, the membrane was cooled to below 30°C for 5 minutes while maintaining the pressure to achieve structural fixation. Subsequently, the resulting composite patch was dried in a vacuum environment for 72 hours to remove residual solvent, yielding a dura mater repair patch with a suture guiding structure.

[0115] Comparative Example 1 (PLLA system monolayer membrane)

[0116] PLLA was dissolved in hexafluoroisopropanol to prepare a spinning solution with a concentration of 18wt%, and electrospinning was performed to prepare a single-layer fiber membrane with a thickness of 180μm.

[0117] The electrospinning parameters are as follows: positive voltage 16kV, negative voltage -2kV, liquid pushing speed 1.0mL / h, receiving distance 16cm, roller speed 400rpm, and spinning time 90min.

[0118] Comparative Example 2 (the only difference from Example 1 is that it is not thickened)

[0119] The difference from Example 1 is that the partitioned hot pressing in step (2) is deleted and replaced with uniform hot pressing.

[0120] Step (2) process is as follows:

[0121] PLCL was dissolved in hexafluoroisopropanol to prepare a spinning solution with a concentration of 12wt% to prepare a B-layer fiber membrane.

[0122] Electrospinning parameters: positive voltage 15kV, negative voltage -2kV, liquid pushing speed 4 mL / h, receiving distance 18cm, roller speed 200rpm, spinning time 45min, initial thickness 150μm; compaction was performed using a hot press mold at a temperature of 105℃ (below the melting point), a pressure of 0.8MPa, to a thickness of 60μm, and a time of 60s.

[0123] Comparative Example 3

[0124] (The only difference from Example 1 is the absence of blind holes)

[0125] The difference from Example 1 is that step (4) of making the blind hole in layer C is deleted, and step (5) is changed to step (4).

[0126] Comparative Example 4

[0127] (The only difference from Example 1 is the through hole)

[0128] The difference from Example 1 is that step (4) of making blind holes in layer C is deleted; and step (5) of drilling holes in the whole piece is added after layer A, layer B and layer C are composited. Therefore, the original "step (5)" is changed to "step (4)" and the content is slightly changed; and "step (5)" is added.

[0129] Step (4) process is as follows:

[0130] Layers A, B, and C were sequentially laid flat on a flatbed hot press. A PTFE anti-adhesion membrane was used on both sides of layers A and C. The temperature was 110°C, which is below the polymer melting point but above the glass transition temperature, causing segmental diffusion at the interface rather than complete melting. This ensured the interlayer bonding strength while maintaining the stability of the porous structure. The pressure was 1.8 MPa, and the time was 90 seconds. After hot pressing, the membrane was cooled to below 30°C for 5 minutes while maintaining the pressure to achieve structural fixation. Subsequently, the resulting composite patch was dried in a vacuum environment for 72 hours to remove residual solvent, yielding a preliminary integrated dura mater repair patch.

[0131] Step (5) process is as follows:

[0132] Suture guide holes are fabricated on the integrated dura mater repair patch using ultraviolet laser drilling. The suture guide holes penetrate the entire thickness of the patch and have a diameter of 0.4 mm. The array of suture guide holes is arranged in a double-row staggered pattern.

[0133] The ultraviolet laser drilling method involves fixing the patch onto a laser processing platform, controlling the laser path via computer to perform point scanning within a set area, using a pulsed laser frequency of 50kHz, a laser power of 8W, and an energy density of 0.7J / mm². 2 The single-hole scanning time is 0.4s, and the laser spot diameter is 0.18mm.

[0134] Comparative Example 5

[0135] The difference from Example 1 is that step (2) of making layer B is deleted; therefore, the original "step (3), step (4), step (5)" are changed to "step (2), step (3), step (4)" respectively; the content of the modified "step (4)" is slightly changed.

[0136] Step (4) process is as follows:

[0137] Layers A and C are laminated to obtain a dura mater repair patch with a suture guidance structure.

[0138] Layers A and C were sequentially laid flat on a flatbed hot press, with PTFE anti-adhesion films applied to both sides of layers A and C. The temperature was 110°C, which is below the polymer melting point but above the glass transition temperature, causing segmental diffusion at the interface rather than complete melting. This ensured the interlayer bonding strength while maintaining the stability of the porous structure. The pressure was 1.3 MPa, and the time was 60 seconds. After hot pressing, the membrane was cooled to below 30°C under the same pressure for 4 minutes to achieve structural fixation. Subsequently, the resulting composite patch was dried in a vacuum environment for 72 hours to remove residual solvent, resulting in a dura mater repair patch with a suture guiding structure.

[0139] Test Example 1

[0140] The suture performance of dura mater repair patches with different structures prepared in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5 was tested.

[0141] Test method for suture retention strength:

[0142] (1) Cut each group of samples into 30mm*10mm specimens, soak them in PBS buffer at 37℃ for 30min and then test them;

[0143] (2) Use 4-0 sutures to perform single-needle sutures 3mm from the edge of the sample and tie the knots in a standard surgical manner (if there are no blind holes, the surgeon can suture by free puncture).

[0144] (3) The main body of the sample is fixed in the lower fixture of the universal testing machine, and the free end of the suture is fixed in the upper fixture. The sample is stretched at a speed of 50 mm / min. The maximum load when the suture is pulled out is recorded as the suture holding strength. Each test group has n=5.

[0145] The suture retention strength results for each group of samples are shown in the figure. Figure 1 .

[0146] Depend on Figure 1 It can be seen that the three-layer dura mater repair patch with blind hole suture guidance structure and locally thickened buffer prepared in the embodiment has a significantly higher suture retention strength than the single-layer membrane structure of Comparative Example 1. This shows that the present invention can effectively improve the tear resistance of the material during the suture fixation process through the design of multi-layer structure and local buffer structure.

[0147] In Comparative Example 2, although a blind-hole suture guide structure was provided, the suture strength decreased to 4.3 ± 0.3 N because no local thickening area was provided in layer B. This indicates that the local thickening buffer structure can further improve the load-bearing capacity of the suture area and reduce stress concentration at the suture.

[0148] Comparative Example 3, with its non-blind hole structure, retains the three-layer structure and the thickened B-layer, resulting in higher overall load-bearing capacity. However, due to the lack of a pre-defined suture guidance area, the needle puncture position is random, easily causing irregular local fiber damage and uneven stress distribution around the hole, thus reducing the suture's stress stability. Therefore, compared to the embodiment, its suture retention strength is still reduced, indicating that the blind hole structure can improve the uniformity of stress around the hole and the consistency of suture by pre-defining the needle puncture position, thereby further improving the suture retention strength.

[0149] Comparative Example 4, with its through-hole structure, exhibits lower suture strength compared to the embodiment and other comparative examples. This is because the through-hole penetrates layers A, B, and C, disrupting the overall continuity of the patch and reducing the effective load-bearing cross-sectional area. Furthermore, the edges of the through-hole easily form continuous stress concentration areas, making the suture more prone to hole expansion and crack propagation during stress, ultimately leading to the suture tearing through the material. Therefore, while the through-hole structure provides suture positioning, it significantly weakens the overall pull-out resistance of the patch.

[0150] Comparative Example 5, which did not have a B-layer buffer structure, maintained a suture strength of 3.7 ± 0.4 N, indicating that the B-layer buffer structure plays an important role in distributing suture load and absorbing local deformation energy.

[0151] In summary, by incorporating a blind-hole suture guide structure, a B-layer buffer structure, and a locally thickened area, this invention can effectively improve the tear resistance and suture stability of the dura mater repair patch during the suture fixation process.

[0152] Test Example 2

[0153] Mechanical properties were tested on the dura mater repair patches with different structures prepared in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5.

[0154] Methods for testing mechanical properties:

[0155] (1) Cut each group of samples into 50mm*10mm specimens, soak them in PBS buffer at 37℃ for 30min and then test them;

[0156] (2) Tensile tests were performed using a universal testing machine with a clamping distance of 30 mm and a tensile speed of 20 mm / min to obtain tensile strength and elongation at break. Each test group had n=5.

[0157] The tensile strength and elongation at break results for each group of samples are shown in the figure. Figure 2 and Figure 3 .

[0158] Depend on Figure 2 and Figure 3 As can be seen, the three-layer composite dura mater repair patch prepared in the embodiment has a tensile strength of 7.2±0.5 MPa, which is significantly higher than that of the single-layer PLLA membrane structure in Comparative Example 1 (5.1±0.4 MPa). This indicates that the PLCL multilayer composite structure used in this invention can effectively improve the overall load-bearing capacity of the material. Meanwhile, the elongation at break in the embodiment reached 138±9%, indicating that while improving the overall mechanical properties, this invention can still maintain good flexibility and deformation adaptability.

[0159] In Comparative Example 2, since layer B did not have a locally thickened area, its tensile strength decreased to 6.6±0.4 MPa, but its elongation at break increased to 145±12%. Because a hot-pressing process was used to make the thickened area of ​​layer B, the fibers were denser, indicating that while the locally thickened structure improves the local load-bearing capacity, it also imposes certain restrictions on the overall free deformation of the material.

[0160] Comparative Example 3, without blind holes, achieved a tensile strength of 7.5 ± 0.5 MPa and an elongation at break of 150 ± 11%, which are among the higher levels in the group. This is because the absence of blind holes makes the material more continuous, thus facilitating continuous load transfer and fiber orientation rearrangement during overall tensile testing, resulting in higher overall tensile performance.

[0161] Comparative Example 4, which uses a through-hole structure, shows a decrease in tensile strength and elongation at break to 5.8±0.5 MPa and 112±9%, respectively. This indicates that the through-hole structure creates a continuous defect region inside the material, which can easily induce premature crack propagation during tensile testing, thereby reducing the overall mechanical stability of the material.

[0162] Comparative Example 5, which did not have a B-layer buffer structure, had a tensile strength and elongation at break of 6.2±0.4 MPa and 125±10%, respectively, which were lower than those of the Example. This indicates that the B-layer buffer structure can not only improve the stress state of the local suture area, but also has a positive effect on the overall deformation coordination and energy absorption.

[0163] In summary, the three-layer composite structure constructed in this invention can effectively improve the overall mechanical properties and structural stability of the material while maintaining high flexibility, making it suitable for dura mater defect repair applications.

[0164] Example 2

[0165] The difference from Embodiment 1 is that the arrangement of the suture guide hole array is a single-row linear arrangement, and includes a first hole area and a second hole area.

[0166] Step (4) process is as follows:

[0167] Suture guide holes are fabricated on the C-layer fiber membrane using ultraviolet laser drilling. These suture guide holes penetrate the thickness of the C-layer and are arranged in a single-row linear array, comprising a first hole area and a second hole area. The first hole area is located near the edge of the patch, with the hole center 3 mm from the patch edge. The hole array is arranged in a single-row linear array, with a center-to-center distance of 2 mm between adjacent holes. The second hole area is located inside the first hole area, with the hole center 7 mm from the patch edge. The hole array is also arranged in a single-row linear array, with a center-to-center distance of 2 mm between adjacent holes.

[0168] The ultraviolet laser drilling method is as follows: the C-layer fiber membrane is fixed on the laser processing platform, and the laser path is controlled by computer to perform point scanning in a set area. The pulse laser frequency is 50kHz, the laser power is 5.5W, the energy density is 0.4J / mm2, the single hole scanning time is 0.15s, and the laser spot diameter is 0.15mm.

[0169] Example 3

[0170] The difference from Example 2 is that only the first hole area is provided.

[0171] Step (4) process is as follows:

[0172] Suture guide holes are processed on the C-layer fiber membrane using ultraviolet laser drilling. The suture guide holes penetrate the thickness of the C-layer. The suture guide hole array is arranged in a single row linear arrangement, with only the first hole area set. The center distance of the hole is 3mm from the edge of the patch. The hole array adopts a single row linear arrangement, and the center distance between adjacent holes is 2mm.

[0173] The ultraviolet laser drilling method involves fixing the C-layer fiber membrane onto a laser processing platform, controlling the laser path via computer to perform point scanning within a set area, using a pulsed laser frequency of 50kHz, a laser power of 5.5W, and an energy density of 0.4J / mm². 2 The single-hole scanning time is 0.15s, and the laser spot diameter is 0.15mm.

[0174] Test Example 3

[0175] Cutting adaptability tests were conducted on the dura mater repair patches with different structures prepared in Examples 2 and 3 to evaluate the ability of the multi-level pore area structure described in Example 2 of the present invention to maintain the suture guidance function and suture retention performance after the patch edge is cut, and compared with Example 3 which only has a single-level pore area structure.

[0176] Test method:

[0177] (1) Cut each group of samples into 30mm*30mm specimens, cut along the parallel direction of the patch edge, and set the cutting distances to 0mm, 4mm, 6mm and 8mm respectively. After cutting, soak them in PBS buffer at 37℃ for 30min before testing.

[0178] (2) Use 4-0 sutures to puncture and suture along the remaining hole area (if the hole area is completely cut off, the surgeon can puncture freely and suture at a distance of 3mm from the cut edge), and tie the knots and fix them using standard surgical methods;

[0179] (3) The main body of the sample is fixed in the lower fixture of the universal testing machine, and the free end of the suture is fixed in the upper fixture. The sample is stretched at a speed of 50 mm / min. The maximum load when the suture is pulled out is recorded as the suture holding strength. Each test group has n=5.

[0180] The suture retention strength results for each group of samples are shown in Table 1.

[0181] Table 1

[0182]

[0183] Experimental results show that the dura mater repair patch with a double-hole structure described in Example 2 of this invention exhibits high and stable suture retention strength under different cutting conditions. In the uncut state, its suture retention strength is 5.5 ± 0.4 N, which is not significantly different from that in Example 3 (5.3 ± 0.4 N), indicating that both have good basic mechanical properties under intact structural conditions.

[0184] When the patch edge is trimmed by 4 mm, in Example 3, due to its single-hole structure, the suture guide structure in the edge area fails, requiring the suturing operation to rely more on free puncture, resulting in uneven local stress distribution and a decrease in suture retention strength to 4.9 ± 0.5 N. In contrast, Example 2, retaining the inner second-hole structure, continues to provide a stable backup suture guide path, maintaining a relatively regular and consistent suture stress position. Therefore, its suture retention strength remains at 5.3 ± 0.4 N, a significantly lower decrease than in Example 3.

[0185] When the cutting was further increased to 6 mm and 8 mm, the first hole area of ​​Example 3 also completely failed, and the patch as a whole entered a holeless guiding state. The suturing behavior was completely dependent on the surgeon's free puncture. Therefore, the strength of the suture tended to be stable, at 4.8 ± 0.5 N and 4.8 ± 0.5 N respectively, without any significant changes, showing typical plateau characteristics after structural degradation.

[0186] In contrast, under the condition of 6 mm cutting, Example 2 can still rely on the second hole area structure to maintain a relatively stable suture guiding function, so that the suture force path still maintains a certain regularity, and its suture holding strength is 5.1 ± 0.4 N. When it is cut to 8 mm, the suture guiding structure in its edge area fails, and the suture holding strength drops to 4.9 ± 0.5 N. The overall downward trend of Example 2 is relatively mild.

[0187] The results show that the dual-hole area structure of the present invention, by setting the main hole area and the spare hole area at different radial positions of the patch, enables the patch to maintain the sewing guidance function through the inner hole area even after the outer hole area fails due to edge cutting. This effectively reduces the adverse effects of cutting on the suture retention performance and ensures that the patch still has good structural stability and sewing reliability under different cutting conditions.

[0188] Therefore, the dura mater repair patch described in Embodiment 2 of the present invention has better cutting adaptability and more stable suture retention performance compared with the single-hole area structure patch, and has good clinical application value.

[0189] Example 4

[0190] (PLCL system + collagen + porous polymer membrane + microneedle punching method)

[0191] A method for preparing a dura mater repair patch with a suture guiding structure, the specific steps of which are as follows:

[0192] (1) Dissolve PLCL in hexafluoroisopropanol to prepare a spinning solution with a concentration of 14wt%, and perform electrospinning to prepare an A-layer fiber membrane with a thickness of 40μm.

[0193] The electrospinning parameters are: positive voltage 14kV, negative voltage -2kV, liquid pushing speed 2.4L / h, receiving distance 17cm, roller speed 500rpm, and spinning time 40min.

[0194] (2) A porous polymer membrane was prepared as the B-layer fiber membrane using the non-solvent induced phase separation method (NIPS method). The specific steps included: first, adding PLCL to hexafluoroisopropanol to prepare a polymer solution with a concentration of 10wt%; then, coating the polymer solution onto a glass substrate; allowing it to evaporate at room temperature for 20s to increase the surface polymer concentration and prevent the membrane from completely dissolving when entering the water bath; then, immediately immersing the substrate in a room temperature water bath (using deionized water) for 3min to allow the solvent and water to exchange and form a microporous structure; and then, in the area corresponding to the C-layer stitching guide hole position, coating or attaching a membrane of the same material, and fixing it by hot pressing and light pressing, with the thickened area having a thickness of 100μm and the other areas having a thickness of 60μm.

[0195] (3) PLCL and collagen were added to hexafluoroisopropanol at a mass ratio of PLCL:collagen = 8:2 to prepare a spinning solution with a concentration of 12wt%, and electrospinning was performed to prepare a C-layer fiber membrane with a thickness of 80μm.

[0196] The electrospinning parameters are: positive voltage 15kV, negative voltage -2kV, liquid pushing speed 4mL / h, receiving distance 16cm, roller speed 400rpm, and spinning time 45min.

[0197] (4) The suture guide hole is processed on the C-layer fiber membrane by micro-needle punching method. The suture guide hole penetrates the thickness of the C-layer and has a diameter of 0.4 mm. The suture guide hole array is arranged in a double-row staggered arrangement, and only the first hole area is set. The center distance of the outer hole is 3 mm from the edge of the patch, and the spacing between the two rows is 2 mm.

[0198] The microneedle punching method is as follows: the stainless steel microneedle tip has a diameter of 0.45mm. The C-layer fiber membrane is laid flat on the rubber pad. The hole position is marked using a positioning template. The microneedle is vertically aligned with the marked point. Appropriate pressure is manually applied to penetrate the C-layer fiber membrane. The punching pressure is 2N. After punching, a circular hole is formed.

[0199] (5) Layers A, B and C are laminated to obtain a dura mater repair patch with a suture guidance structure.

[0200] Layers A, B, and C were sequentially laid flat on a flatbed hot press. A PTFE anti-adhesion membrane was used on both sides of layers A and C. The temperature was 110°C, which is below the polymer melting point but above the glass transition temperature, causing segmental diffusion at the interface rather than complete melting. This ensured the interlayer bonding strength while maintaining the stability of the porous structure. The pressure was 1.8 MPa, and the time was 90 seconds. After hot pressing, the membrane was cooled to below 30°C for 5 minutes while maintaining the pressure to achieve structural fixation. Subsequently, the resulting composite patch was dried in a vacuum environment for 72 hours to remove residual solvent, yielding a dura mater repair patch with a suture guiding structure.

[0201] Example 5

[0202] (PLCL system + collagen + elastic polymer coating + microneedle punching method)

[0203] The difference from Example 4 is that step (2) uses an "elastic polymer coating" instead of a "porous polymer membrane", while the rest of the steps are the same as in Example 1.

[0204] Step (2) process is as follows:

[0205] PLCL was dissolved in hexafluoroisopropanol to prepare a coating solution with a concentration of 8wt%. The coating method was blade coating. The dense fiber film of layer A was laid flat on the glass substrate, and the edges of the film were fixed with tape. The coating solution was evenly dripped onto the film surface and uniformly coated with a blade at a moving speed of 10mm / s. After coating, the film was immediately placed in a ventilated environment to evaporate the solvent. After the surface was initially dried, the non-thickened areas were masked with a template, and the hole areas were coated twice. The coating was then evaporated at room temperature for 30 minutes and then dried in a vacuum oven at 40℃ for 12 hours. The thickness of the thickened area was 100μm, and the thickness of other areas was 60μm.

[0206] Example 6

[0207] (PLCL system + collagen + loose fiber layer + microneedle punching method)

[0208] The difference from Example 4 is that step (2) uses a “loose fiber layer” instead of a “porous polymer membrane”, while the rest of the steps are the same as in Example 1.

[0209] Step (2) process is as follows:

[0210] PLCL was dissolved in hexafluoroisopropanol to prepare a spinning solution with a concentration of 12wt%.

[0211] Electrospinning parameters: positive voltage 15kV, negative voltage -2kV, liquid pushing speed 4 mL / h, receiving distance 18cm, roller speed 200rpm, spinning time 45min, initial thickness 150μm; selective compaction of areas was performed using a zoned hot-pressing mold, with a hot-pressing temperature of 45-60℃ (below the melting point), a pressure of 0.2MPa for the thickened area to 100μm, and a pressure of 0.8MPa for other areas to 60μm, for 60s.

[0212] Example 7

[0213] (PLLA system + gelatin + porous polymer membrane + microneedle punching method)

[0214] The difference from Example 4 is that in step (1), “PLLA” is used to replace “PLCL” in an equal amount, and in step (3), “gelatin” is used to replace “collagen” in an equal amount. The remaining steps are the same as in Example 1.

[0215] Step (1) process is as follows:

[0216] PLLA was dissolved in hexafluoroisopropanol to prepare a spinning solution with a concentration of 14wt%, and electrospinning was performed to prepare an A-layer fiber membrane with a thickness of 40μm.

[0217] The electrospinning parameters are as follows: positive voltage 14kV, negative voltage -2kV, liquid pushing speed 2.4L / h, receiving distance 17cm, roller speed 500rpm, and spinning time 40min.

[0218] Step (3) process is as follows:

[0219] PLCL and gelatin were added to hexafluoroisopropanol at a mass ratio of PLCL:gelatin = 8:2 to prepare a spinning solution with a concentration of 12wt%. Electrospinning was then performed to prepare a C-layer fiber membrane with a thickness of 80μm.

[0220] The electrospinning parameters are as follows: positive voltage 15kV, negative voltage -2kV, liquid pushing speed 4mL / h, receiving distance 16cm, roller speed 400rpm, and spinning time 45min.

[0221] Example 8

[0222] (Layer A is PLLA system + Layer B is PCL system + gelatin + porous polymer membrane + UV laser perforation)

[0223] The difference from Example 4 is that: in step (1), PLLA is used to replace PLCL in an equal amount; in step (2), PCL is used to replace PLCL in an equal amount; in step (3), gelatin is used to replace collagen in an equal amount; in step (4), ultraviolet laser drilling is used to replace microneedle punching. The remaining steps are the same as in Example 1.

[0224] The ultraviolet laser drilling method described in step (4) is as follows:

[0225] The C-layer fiber membrane was fixed on a laser processing platform, and the laser path was controlled by a computer to perform point scanning in a set area. The pulsed laser frequency was 50kHz, the laser power was 5.5W, and the energy density was 0.4J / mm². 2 The single-hole scanning time is 0.15s, and the laser spot diameter is 0.15mm. The aperture can be controlled by controlling the scanning time.

[0226] Example 9

[0227] (Layer A is PLLA system + Layer B is PCL system + gelatin + porous polymer membrane + mold pre-drilled hole method)

[0228] The difference from Example 4 is that: in step (1), PLLA is used to replace PLCL in an equal amount; in step (2), PCL is used to replace PLCL in an equal amount; in step (3), gelatin is used to replace collagen in an equal amount; in step (4), the pre-drilled hole method is used instead of the micro-needle punching method, and the remaining steps are the same as in Example 1.

[0229] The method for pre-forming holes in the mold described in step (4) is as follows:

[0230] A porous structure is formed directly during the spinning process in the C layer. A micro-bump array is set on the spinning receiving plate. The bumps are made of stainless steel or silicone, with a diameter of 0.7 mm and a height of 0.5 mm. Electrospinning is performed, and as the fibers are deposited on the receiving plate, the fiber deposition density in the bump area is significantly reduced or a thin layer is formed due to electric field distortion and physical obstruction. Pores are formed by slight airflow purging or slight mechanical treatment. The fiber membrane is then removed, revealing regular pores formed at the bump locations. This porous structure penetrates the C layer.

[0231] Since layer C will be combined with layers B and A in the future, the hole only exists in layer C. After the three layers are combined, the bottom of the hole is sealed by layer B, forming a structural suture guide hole.

[0232] Example 10

[0233] (Layer A is a PGA system + Layer B is a PGA system + gelatin + porous polymer membrane + mold pre-formed hole method)

[0234] The difference from Example 4 is that: in step (1), PGA is used to replace PLCL in equal amounts; in step (2), PGA is used to replace PLCL in equal amounts; in step (3), gelatin is used to replace collagen in equal amounts; in step (4), the mold pre-drilling method is used to replace the micro-needle punching method, and the remaining steps are the same as in Example 1.

[0235] The method for pre-forming holes in the mold described in step (4) is as follows:

[0236] A porous structure is formed directly during the spinning process in the C layer. A micro-bump array is set on the spinning receiving plate. The bumps are made of stainless steel or silicone, with a diameter of 0.7 mm and a height of 0.5 mm. Electrospinning is performed, and as the fibers are deposited on the receiving plate, the fiber deposition density in the bump area is significantly reduced or a thin layer is formed due to electric field distortion and physical obstruction. Pores are formed by slight airflow purging or slight mechanical treatment. The fiber membrane is then removed, revealing regular pores formed at the bump locations. This porous structure penetrates the C layer.

[0237] Since layer C will be combined with layers B and A in the future, the hole only exists in layer C. After the three layers are combined, the bottom of the hole is sealed by layer B, forming a structural suture guide hole.

[0238] Example 11

[0239] (Layer A is PLA system + Layer B is PGA system + gelatin + porous polymer membrane + mold pre-drilled hole method)

[0240] The difference from Example 4 is that: in step (1), PLA is used to replace PLCL in equal amounts; in step (2), PGA is used to replace PLCL in equal amounts; in step (3), gelatin is used to replace collagen in equal amounts; in step (4), the pre-drilled hole method is used instead of the micro-needle punching method, and the remaining steps are the same as in Example 1.

[0241] The method for pre-forming holes in the mold described in step (4) is as follows:

[0242] A porous structure is formed directly during the spinning process in the C layer. A micro-bump array is set on the spinning receiving plate. The bumps are made of stainless steel or silicone, with a diameter of 0.7 mm and a height of 0.5 mm. Electrospinning is performed, and as the fibers are deposited on the receiving plate, the fiber deposition density in the bump area is significantly reduced or a thin layer is formed due to electric field distortion and physical obstruction. Pores are formed by slight airflow purging or slight mechanical treatment. The fiber membrane is then removed, revealing regular pores formed at the bump locations. This porous structure penetrates the C layer.

[0243] Since layer C will be combined with layers B and A in the future, the hole only exists in layer C. After the three layers are combined, the bottom of the hole is sealed by layer B, forming a structural suture guide hole.

[0244] Testing revealed that the suture performance and mechanical properties of the dura mater repair patches obtained in Examples 4-11 were not significantly different from those in Example 1.

[0245] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A dura repair patch having suture guide structures, characterized in that, The dura mater repair patch comprises at least three layers: layer A, layer B, and layer C. Layer A faces the brain, layer C faces the skull, and layer B is positioned between layer A and layer C to form an interlayer buffer layer. The C layer is provided with a suture guide hole, which extends inward from the C layer to form a blind hole structure and terminates in the B layer; the B layer is provided with a thickened area in the region corresponding to the blind hole structure of the C layer.

2. The dura repair patch having suture guide structures of claim 1, wherein, The B-layer buffer structure is selected from any one of porous polymer membrane structure, elastic polymer coating structure, and loose fiber layer structure.

3. The dura repair patch having suture guide structures of claim 1, wherein, The suture guide hole includes either a continuous guide type or an intermittent guide type; The continuous guide type has a hole center spacing of 1.5-3mm, and guides needles one by one; The spaced guide type has a hole center spacing of 4-8mm, and a guide point is set every 2-3 pins.

4. The dura repair patch having suture guide structures of claim 1, wherein, The suture guide hole array includes at least two hole areas distributed radially along the patch, wherein the center of the hole in the first hole area is 2-4 mm from the edge; the second hole area is located inside the first hole area, and the center of the hole is 5-10 mm from the edge; the arrangement of the suture guide hole array includes any one of the following: single-row linear arrangement, double-row linear arrangement, double-row staggered arrangement, ring or elliptical array.

5. The dura mater repair patch with a suture guiding structure according to claim 1, characterized in that, Layers A, B, and C are all made of biodegradable polymer materials.

6. The dura mater repair patch with a suture guiding structure according to claim 5, characterized in that, The biodegradable polymer material is selected from at least one of aliphatic polyester materials and natural polymer materials; The aliphatic polyester material includes blends of any one or more of polylactic acid, polyglycolic acid, polycaprolactone, polylactic acid-glycolic acid copolymer, and polylactic acid-caprolactone copolymer. The natural polymer material includes any one or a blend of collagen, gelatin, chitosan or hyaluronic acid.

7. The method for preparing a dura mater repair patch with a suture guiding structure according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Using biodegradable polymer materials as raw materials, prepare spinning solution, perform electrospinning, and prepare A-layer fiber membrane; (2) Porous polymer membrane, using biodegradable polymer as raw material, B layer fiber membrane is prepared by non-solvent induced phase separation method, and thickened area is formed in the region corresponding to the blind pore structure of C layer by local stacking method; (3) Prepare spinning solution using aliphatic polyester materials or a mixture of aliphatic polyester materials and natural polymer materials as raw materials, and perform electrospinning to prepare C-layer fiber membrane; (4) A suture guide hole is fabricated on the C-layer fiber membrane; (5) Layers A, B and C are laminated to obtain a dura mater repair patch with a suture guidance structure.

8. The method for preparing the dura mater repair patch according to claim 7, characterized in that, The porous polymer membrane described in step (2) is replaced with an elastic polymer coating; The method for preparing the elastic polymer coating includes: using a biodegradable polymer as raw material, curing it after spraying or dipping, and selectively coating to form a local thickening area in the region corresponding to the blind hole structure of layer C.

9. The method for preparing the dura mater repair patch according to claim 7, characterized in that, The porous polymer membrane in step (2) is replaced with a loose fiber layer; the preparation method of the loose fiber layer includes: using a biodegradable polymer as raw material, preparing a loose fiber layer by electrospinning process, and selectively compacting the region during hot pressing process to maintain a larger thickness in the region corresponding to the blind pore structure, forming a relatively thickened region; the interlayer composite in step (5) includes any one of hot pressing process and electrospinning process.

10. The application of the dura mater repair patch according to any one of claims 1-6, or the dura mater repair patch prepared according to the method of claims 7-9, in the field of dura mater defect repair.

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