Repair membrane and preparation method therefor

Abstract

The present invention relates to the technical field of biomaterials. Disclosed are a repair membrane and a preparation method therefor. The preparation method comprises the following steps: S1, preparing a polymer membrane; S2, mixing the polymer membrane with a natural polymer material solution, and performing unidirectional freezing to prepare a through hole structure; and S3, cross-linking a composite membrane of a polymer and a natural polymer material to obtain a repair membrane. According to the repair membrane and the preparation method therefor provided by the present invention, the repair membrane prepared takes a polymer material as a support and slow-degradation inner layer and takes a cross-linked natural polymer material having a unidirectional channel as a guide outer layer. When the present application is applied to repair of soft tissues such as smooth muscle, blood vessels, and tendons, a gelatin unidirectional channel can guide directed cell migration, adhesion, proliferation, and alignment, and a polymer of an inner layer can ensure the matching between the degradation rate of the material and tissue growth, so that the present invention can achieve a better tissue repair effect.

Description

Repair film and preparation method thereof Technical Field

[0001] The present invention relates to the technical field of biomaterials, and in particular to a repair membrane and a preparation method thereof. Background Art

[0002] Biomaterials are widely used in regenerative medicine. These materials usually act as temporary fillers and gradually degrade and metabolize as the tissue itself grows. In this process, not only the type and properties of the material will affect tissue repair, but the macro and micro structures of the material also play an important role. In human tissue, cells and extracellular matrix are often distributed according to certain rules, and most of the time they are distributed according to the direction of the force applied to the tissue. For example, the collagen fibers in tendons and ligaments are almost all arranged in one direction, the muscle fibers of smooth muscle and skeletal muscle are also arranged in the direction of contraction force, and the trabeculae of cancellous bone will also grow more densely in the direction where the force needs to be applied. In the process of these tissues having defects and needing to be implanted with biomaterials for repair, the microstructure of the material plays an important role. A structure that can guide cells to migrate, grow and proliferate in the direction where the force needs to be applied will have a better repair effect. The present invention provides a repair membrane and a preparation method thereof, which prepares directional channels of natural polymer materials through unidirectional freezing, while other existing membranes do not have such a directional structure.

[0003] Biomaterials implanted in the human body must meet not only the necessary safety and biocompatibility requirements but also functionality. For example, oral repair membranes, hernia patches, and anti-adhesion membranes all require physical isolation, while artificial tendons require more tensile strength. The present invention provides a repair membrane and preparation method that not only possesses a directional pore structure but also possesses high mechanical strength when combined with polymer materials. Therefore, it can not only meet clinical needs in a variety of application scenarios but also exhibit better overall performance than other biorepair membranes.

[0004] After implantation, materials slowly degrade under the influence of cells and body fluids. However, the rate of degradation also affects tissue growth. Some materials, such as calcium sulfate, degrade too quickly, often completely degrading before tissues have fully grown. Other materials, such as polylactic acid, degrade too slowly, limiting tissue growth.

[0005] Currently, there are relatively few repair membranes clinically used for soft tissue, especially in specific application scenarios. For example, repair membranes are used to repair the myometrium after cesarean section. With the increasing cesarean section rate in recent years, uterine scar defects and other cesarean section-related complications have increased accordingly. Using repair membranes for repair is a promising treatment strategy, as they can promote the healing of uterine scar incisions and reduce the incidence of scar healing defects and postoperative menstrual abnormalities. However, existing biofilms are not very satisfactory for repairing the myometrium.

[0006] Summary of the Invention

[0007] The present invention provides a repair membrane and its preparation method. Directed channels of natural polymer materials are created through unidirectional freezing, and the polymer materials are then combined to form a repair membrane. The outer layer of the repair membrane uses natural polymer materials, while the inner layer uses synthetic polymer materials. This ensures excellent biocompatibility while ensuring that the rate of tissue regeneration matches the rate of membrane degradation. Therefore, the repair membrane can be applied to a variety of defect repair scenarios, achieving clinical results unattainable by other biological membranes.

[0008] A method for preparing a repair membrane comprises the following steps:

[0009] S1 preparation of polymer membrane;

[0010] S2 mixes the polymer membrane with a natural polymer material solution and freezes it in one direction to prepare a through-hole structure;

[0011] S3 cross-links the composite film of the polymer and the natural polymer material to obtain a repair film.

[0012] The present invention can use commercially available polymer membranes, or can be prepared using existing methods, such as 3D printing, electrospinning, and the like.

[0013] Optionally, the polymer membrane material is polylactic acid, polyglycolic acid, polycaprolactone, and copolymerization and blending combinations of these polyesters (such as copolymerization products of polycaprolactone and polylactic acid).

[0014] Preferably, the polymer film is printed by a near-field direct writing 3D printer. Optionally, the printing material is polycaprolactone, polylactic acid, or a copolymer of polycaprolactone and polylactic acid, PLCL.

[0015] Furthermore, the polymer membrane is obtained by the following method: the printing material is polycaprolactone, polylactic acid, or PLCL, a copolymer of polycaprolactone and polylactic acid; the printing temperature is 50-230°C; the printing pressure is 0-50KPa; the printing voltage is 1-20KV; the number of printing layers is 1-30 layers; and the minimum grid size of the printed structure is 0.1-5mm.

[0016] Preferably, the natural polymer material is a combination of one or more protein polymers such as gelatin, collagen, silk fibroin, etc. and polysaccharide polymers such as hyaluronic acid, alginate, chitosan, starch, etc. More preferably, the natural polymer material is collagen, silk fibroin, gelatin.

[0017] Preferably, step S2 specifically includes:

[0018] S21 prepares a natural polymer material solution;

[0019] S22: placing the polymer film into a mold, placing the mold on a one-way freezing platform, then pouring in a natural polymer material solution, and placing the solution in a refrigerator to heat up after freezing and solidifying;

[0020] After S23 is heated, it is placed in a freeze dryer for drying, and a composite film is obtained after drying.

[0021] The natural polymer material solution uses water as a solvent. The mass percentage concentration of the natural polymer material solution is 0.1 to 10%, and more preferably 0.5 to 4%.

[0022] Optionally, after the natural polymer material solution is prepared, the natural polymer material solution may be cooled to 35-40°C.

[0023] Preferably, the one-way freezing platform is a flat metal plate with a temperature of 0 to -200°C; the refrigerator temperature is 0 to -20°C.

[0024] Preferably, the operating steps of unidirectional freezing are: place a polymer film (such as a polycaprolactone film) into a mold, place the mold on a unidirectional freezing platform, keep the polymer film perpendicular to the unidirectional freezing platform, the freezing platform temperature is -200°C to -80°C, then pour in the gelatin solution, and put it into the refrigerator after the solution is frozen and solidified.

[0025] As an embodiment, step S3 includes:

[0026] S31 prepares a cross-linking solution;

[0027] S32: placing the composite membrane into a cross-linking solution, degassing, and then cross-linking;

[0028] After S33 cross-linking, the cross-linking agent is removed and the repaired membrane is obtained after drying.

[0029] Preferably, the cross-linking agent is one or more of glutaraldehyde, carbodiimide, genipin, and diisocyanate; and the cross-linking solvent is one or more of water, ethanol, isopropanol, butanediol, and glycerol.

[0030] Optionally, the mass percentage concentration of the cross-linking agent is 0.01 to 5%.

[0031] Preferably, the cross-linking solvent is a mixed solvent including water and one or more of ethanol, isopropanol, butanediol, and glycerol, to ensure that the solvent does not dissolve the freeze-dried composite membrane and to ensure the qualitative pore structure.

[0032] Preferably, the volume percentage of water in the cross-linking solvent is 0.1 to 50%; further preferably, the volume percentage of water in the cross-linking solvent is 5 to 50%; further preferably, it is 5 to 30%; further preferably, it is 5 to 25%; more specifically, it is 10 to 25%; and more specifically, it is 15%.

[0033] Optionally, the air pressure used for the degassing is 10-100000 Pa; the cleaning solution for removing the cross-linking agent is one or more of water, ethanol, and isopropanol; and the drying temperature is 20-60°C.

[0034] A repair membrane is obtained by the preparation method described in any of the above technical solutions.

[0035] The repair membrane is a three-layer structure, with the polymer membrane in the middle and natural polymer material layers with directional pore structures on both sides.

[0036] Optionally, the diameter of the directional channel is 1-1000 μm. More preferably, the diameter of the directional channel is greater than 50 μm. Furthermore, the diameter of the directional channel is greater than 60 μm. In some embodiments, the diameter of the resulting directional channel is greater than 80 microns. As a preferred embodiment, the diameter of the directional channel is 50-1000 μm, further 60-1000 μm, and further 70-1000 μm; more specifically, the diameter of the resulting directional channel is 60-500 μm or 70-500 μm.

[0037] The preparation method of the repair film provided by the present invention has the following advantages:

[0038] The present invention uses unidirectional freezing to prepare a unidirectional channel of natural polymer materials, and at the same time combines the polymer materials and cross-linked natural polymer materials to prepare a repair membrane. The ordered through-holes of this repair membrane can guide the better repair of the uterine muscle layer and also have a good repair effect on other soft tissues with ordered structures. At the same time, the polymer materials prepared by 3D printing ensure the matching of material degradation and autologous tissue growth, which is a safe and effective new type of biological repair membrane.

[0039] The repair membrane of the present invention is used for repairing the myometrium after cesarean section. Its ordered through holes can guide better repair of the myometrium and prevent uterine diverticula. At the same time, the polymer material ensures the matching of material degradation and autologous tissue growth. It is a safe and effective repair membrane for repairing the myometrium.

[0040] The repair membrane and its preparation method provided by the present invention utilize a polymer material as a support and slowly degrading inner layer, and a cross-linked natural polymer material with unidirectional channels as a guiding outer layer. When applied to soft tissue repair, such as smooth muscle, blood vessels, and tendons, the unidirectional channels of gelatin can guide directional cell migration, adhesion, proliferation, and alignment, while the polymer in the inner layer ensures that the degradation rate of the material matches tissue growth. Therefore, the present invention can achieve better tissue repair results.

[0041] In summary, the repair membrane and preparation method thereof provided by the present invention have better comprehensive performance than other biological membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG1 is a schematic diagram showing the structure of the repair membrane of the present invention;

[0043] FIG2 is an appearance diagram of the repair film prepared in Example 1 of the present invention;

[0044] FIG3 is a microscope photograph of the repair film prepared in Example 1 of the present invention;

[0045] FIG4 is a microscope photograph of the repair film prepared in Example 1 of the present invention from another direction;

[0046] FIG5 is an appearance diagram of the repair film prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0047] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0048] The structure of the repair film of the present invention is shown in FIG1 , wherein the upper figure in FIG1 is a disassembled view of the repair film, and the lower figure in FIG1 is a cross-sectional view of the repair film.

[0049] Example 1

[0050] This embodiment provides a method for preparing a repair film, which comprises the following steps:

[0051] S11: Place polycaprolactone material in the printer barrel and set the following printing parameters: barrel temperature 90°C, needle 130°C, air pressure 40 kPa, voltage 4.5 kV, height 3 mm, speed 1000 mm / min, number of layers 8, print pitch 500 μm, size 10 × 50 mm, grid size 500 × 500 μm. Use the printer's built-in software to generate code and print the polycaprolactone film.

[0052] S21: Soak 1 gram of gelatin in 100 ml of purified water for 20 minutes, then heat to 60°C until the gelatin is completely dissolved to obtain a 1% gelatin solution. Then cool to 35-40°C.

[0053] S22: Place the polycaprolactone film into the mold, and place the mold on a one-way freezing platform (in this embodiment, the polycaprolactone film is arranged perpendicular to the one-way freezing platform), the freezing platform temperature is -196°C, and then pour the gelatin solution. After the solution is frozen and solidified, put it in the refrigerator for 2 hours, and the refrigerator temperature is -20°C.

[0054] S23: placing the mold into a freeze dryer for drying for 24 hours to obtain a composite film.

[0055] S31: prepare a cross-linking solution, which is 85 ml of anhydrous ethanol, 15 ml of purified water, and 1 ml of 50% glutaraldehyde, and add them in order and stir for 10 minutes.

[0056] S32: The composite film is placed in a cross-linking liquid, and then placed in a vacuum oven to evacuate the air. After no bubbles emerge, the cross-linking liquid is taken out of the oven and allowed to stand for 2 hours.

[0057] S33: The composite membrane is taken out, washed with anhydrous ethanol and purified water, and then dried in a forced air drying oven to obtain a repaired membrane.

[0058] The resulting composite membrane is shown in Figure 2, and a microscopic photograph of the cross section of the composite membrane is shown in Figure 3. The pore sizes are all above 130 microns. A microscopic photograph of the side of the composite membrane is shown in Figure 4, and the pore sizes are all above 150 microns.

[0059] Example 2

[0060] This embodiment provides a method for preparing a repair film, which comprises the following steps:

[0061] S11: Place polycaprolactone material into the printer barrel and set the printing parameters: barrel temperature 90°C, needle 130°C, air pressure 40 kPa, voltage 4.5 kV, height 3 mm, speed 1000 mm / min, number of layers 8, print pitch 500 microns, size 10 × 50 mm. Use the printer's built-in software to generate code and print the polycaprolactone film.

[0062] S21: Soak 2 grams of gelatin in 100 ml of purified water for 20 minutes, then heat to 60°C until the gelatin is completely dissolved to obtain a 2% gelatin solution. Then cool to 35-40°C.

[0063] S22: Place the polycaprolactone film into a mold, place the mold on a one-way freezing platform with a freezing platform temperature of -90°C, then pour in the gelatin solution, and after the solution is frozen and solidified, place it in a refrigerator for 2 hours with a refrigerator temperature of -20°C.

[0064] S23: placing the mold into a freeze dryer for drying for 24 hours to obtain a composite film.

[0065] S31: prepare a cross-linking solution, which is 85 ml of anhydrous ethanol, 15 ml of purified water, and 1 ml of 50% glutaraldehyde, and add them in order and stir for 10 minutes.

[0066] S32: The composite film is placed in a cross-linking liquid, and then placed in a vacuum oven to evacuate the air. After no bubbles emerge, the cross-linking liquid is taken out of the oven and allowed to stand for 2 hours.

[0067] S33: The composite membrane is taken out, washed with anhydrous ethanol and purified water, and then dried in a forced air drying oven to obtain a repaired membrane.

[0068] Comparative Example 1

[0069] This embodiment provides a method for preparing a repair film, which comprises the following steps:

[0070] S11: Place polycaprolactone material into the printer barrel and set the printing parameters: barrel temperature 90°C, needle 130°C, air pressure 40 kPa, voltage 4.5 kV, height 3 mm, speed 1000 mm / min, number of layers 8, print pitch 500 microns, size 10 × 50 mm. Use the printer's built-in software to generate code and print the polycaprolactone film.

[0071] S21: Soak 1 gram of gelatin in 100 ml of purified water for 20 minutes, then heat to 60°C until the gelatin is completely dissolved to obtain a 1% gelatin solution. Then cool to 35-40°C.

[0072] S22: Place the polycaprolactone film into a mold, place the mold on a one-way freezing platform with a freezing platform temperature of -90°C, then pour in the gelatin solution, and after the solution is frozen and solidified, place it in a refrigerator for 2 hours with a refrigerator temperature of -20°C.

[0073] S23: placing the mold into a freeze dryer for drying for 24 hours to obtain a composite film.

[0074] S31: prepare a cross-linking solution, which is 15 ml of anhydrous ethanol, 85 ml of purified water, and 1 ml of 50% glutaraldehyde, and add them in order and stir for 10 minutes.

[0075] S32: The composite film is placed in a cross-linking liquid, and then placed in a vacuum oven to evacuate the air. After no bubbles emerge, the cross-linking liquid is taken out of the oven and allowed to stand for 2 hours.

[0076] S33: The composite membrane is taken out, washed with anhydrous ethanol and purified water, and then dried in a forced air drying oven to obtain a repaired membrane.

[0077] The purified water content of the cross-linking solution is too high, causing the gelatin to swell and unable to maintain its original unidirectional pore structure, as shown in Figure 5.

Claims

1. A method for preparing a repair film, characterized in that: The steps include: S1 preparation of polymer membrane; S2 mixes the polymer membrane with the natural polymer material solution and prepares a through-hole structure by unidirectional freezing; S3 cross-links the composite film of the polymer and the natural polymer material to obtain a repair film.

2. The method for preparing a repair film according to claim 1, characterized in that: The polymer film material is polylactic acid, polyglycolic acid, polycaprolactone, copolymers of these polyesters, or blends of two or more of these polyesters.

3. The method for preparing a repair film according to claim 1, characterized in that: The natural polymer material is one or more combinations of gelatin, collagen, silk fibroin, hyaluronic acid, alginate, chitosan and starch.

4. The method for preparing a repair film according to claim 1, characterized in that: Step S2 specifically includes: S21 prepares natural polymer material solution; S22: placing the polymer film into a mold, placing the mold on a one-way freezing platform, and then pouring in a natural polymer material solution, and placing the solution in a refrigerator to heat up after freezing and solidification; After S23 is heated, it is placed in a freeze dryer for drying, and a composite film is obtained after drying.

5. The method for preparing a repair film according to claim 1, characterized in that: The cross-linking agent is one or more of glutaraldehyde, carbodiimide, genipin, and diisocyanate; and the cross-linking solvent is one or more of water, ethanol, isopropanol, butanediol, and glycerol.

6. The method for preparing a repair film according to claim 1 or 5, characterized in that: The one-way freezing platform is a flat metal plate with a temperature of 0 to -200°C; the refrigerator temperature is 0 to -20°C.

7. The method for preparing a repair film according to claim 5, characterized in that: The cross-linking solvent is a mixed solvent, including water and one or more of ethanol, isopropanol, butanediol and glycerol; in the cross-linking solvent, the volume percentage of water is 0.1-50%.

8. The method for preparing a repair film according to claim 7, characterized in that: In the cross-linking solvent, the volume percentage of water is 10-25%.

9. The method for preparing a repair film according to claim 1, characterized in that: The polymer membrane is printed by a 3D printer.

10. A repair film, characterized in that: Obtained by the preparation method described in any one of claims 1 to 9; the repair membrane is a three-layer structure, with the polymer membrane in the middle and natural polymer material layers with directional pore structures on both sides.

11. The repair film according to claim 10, characterized in that: The diameter of the directional channel is 1-1000 μm.

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