Composite multi-layer anti-adhesion film and preparation method thereof

Abstract

The present invention discloses a composite multi-layer anti-adhesion membrane and a preparation method thereof. Carboxymethyl cellulose and a biodegradable high molecular polymer are made into a composite membrane. The surface carboxymethyl cellulose contacts the damaged tissue to provide initial adhesion so that the membrane is tightly attached to the tissue, avoiding movement of the isolation membrane and leakage of the anastomosis. It can effectively stop bleeding and prevent other body fluids and fibrinogen from seeping out. The gradual dissolution of the carboxymethyl cellulose in the mixed fiber layer avoids the carboxymethyl cellulose from being diluted too quickly and absorbed by the body, making it difficult to maintain a stable concentration and amount at the damaged site for a long time. As the carboxymethyl cellulose in the mixed fiber layer is gradually diluted and absorbed, the remaining loose high molecular polymer structure can guide fibroblasts to grow into the membrane, promote wound healing, and keep the anti-adhesion membrane fixed to the tissue. The high molecular polymer base layer on the other side has a dense structure that can effectively prevent fibroblasts from breaking through the anti-adhesion membrane, providing an anti-adhesion effect.

Description

Technical Field

[0001] The present invention relates to the field of biomedical materials, and in particular to a composite multi-layer anti-adhesion film and a preparation method thereof. Background Art

[0002] Postoperative adhesions can occur in virtually any part of the body undergoing surgical intervention, but are particularly common after abdominal and pelvic, tendon, and spinal surgeries. They typically occur during the healing process of traumatic tissue. They can lead to a variety of serious complications, such as intestinal obstruction, chronic abdominal pain, and female infertility, severely impacting surgical outcomes and patients' quality of life, increasing their emotional and financial burdens, and even potentially leading to death. To prevent tissue adhesions, surgical anti-adhesion products are essential.

[0003] The most commonly used solid barrier membranes in China are made of polylactic acid (PLA). PLA is non-toxic, non-irritating, and non-antigenic, and has excellent biocompatibility. However, PLA is a hydrophobic material with poor tissue adhesion, making it difficult to adhere tightly to tissues and requiring additional suturing.

[0004] Chinese patent publication number CN105194739A provides a double-layer anti-adhesion membrane. This membrane is prepared by electrospinning a polymer nanofiber membrane, which is then placed in a mold and coated with a gel solution. The membrane is freeze-dried to obtain a double-layer anti-adhesion membrane. Chinese patent publication number CN1994476A provides a biodegradable composite biomaterial medical membrane. A base layer is prepared by electrospinning a copolymer of one or both of polylactic acid and polyglycolic acid. The biodegradable composite medical membrane is then coated or sprayed with a chitosan aqueous solution.

[0005] The tissue adhesion of the two patented anti-adhesion membranes mentioned above depends on the surface gel layer or chitosan, but the complex environment in the body may cause the surface layer to be quickly diluted or absorbed, and the remaining polymer layer is difficult to maintain at the site of injury, causing it to fall off.

[0006] Chinese patent publication number CN104368049A discloses a hemostatic and anti-adhesion composite material based on an oxidized cellulose system. The composite fiber material is electrospun from hemostatic powder and anti-adhesion fibers, which are then heat-pressed to form the resulting hemostatic and anti-adhesion composite material. While this product offers good hemostatic effects, the degradation rate of the hemostatic powder within the composite fiber layer is difficult to maintain uniformly upon dilution, making it difficult to guarantee the fibroblast-blocking effect of the entire membrane. Its anti-adhesion effectiveness remains questionable.

[0007] At present, the solid isolation membrane anti-adhesion products widely used in clinical practice have an anti-adhesion effect limited to a small part of the tissue surface covered by the isolation membrane, and cannot be tightly attached to the wound and its surrounding tissues. If not sutured, the isolation membrane may move and the anastomosis may leak, and it cannot effectively prevent the leakage of other body fluids and fibrinogen.

[0008] Therefore, how to realize an anti-adhesion product that can avoid being diluted too quickly and absorbed by the body while providing better hemostasis and anti-adhesion effects is one of the research directions that technicians in this field are committed to. Summary of the Invention

[0009] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a composite multi-layer anti-adhesion film and a preparation method thereof.

[0010] The object of the present invention is achieved like this:

[0011] The composite multi-layer anti-adhesion membrane of the present invention comprises, in sequence, a polymer base layer composed of a biodegradable polymer, a mixed fiber layer formed on the surface of the polymer base layer, and a gel layer formed on the surface of the mixed fiber layer;

[0012] The material of the gel layer is carboxymethyl cellulose, and the thickness of the gel layer is 0.001-0.03 mm;

[0013] The mixed fiber layer is made of mixed fibers composed of a biodegradable polymer and carboxymethyl cellulose, the mass ratio of the biodegradable polymer to the carboxymethyl cellulose is 0.5-5:1, the mixed fiber layer has a thickness of 0.01-0.1 mm and a pore size of 60-250 μm;

[0014] The pore size of the polymer base layer is ≤20 μm, the porosity is >70%, and the thickness of the polymer base layer is 0.01-0.03 mm;

[0015] The molecular weight of the carboxymethyl cellulose is 250-1000 kDa.

[0016] The above-mentioned composite multi-layer anti-adhesion film, wherein the preparation method of the mixed fiber layer comprises:

[0017] The biodegradable polymer and carboxymethyl cellulose are respectively formed into spinning solutions, and the injection needles are arranged in a staggered manner to obtain the mixed fiber layer by electrospinning;

[0018] Alternatively, a biodegradable high molecular polymer is mixed with carboxymethyl cellulose to prepare a W / O solution, which is then electrospun to prepare a uniform fiber layer, namely the mixed fiber layer.

[0019] In the above-mentioned composite multi-layer anti-adhesion film, the biodegradable high molecular polymer is polylactic acid PLA or polylactic acid-glycolic acid copolymer PLGA.

[0020] The present invention also provides a method for preparing a composite multi-layer anti-adhesion film, comprising the following steps:

[0021] Step 1: dissolving a biodegradable polymer in an organic solvent to obtain a polymer spinning solution with a mass concentration of 5%-30%, extruding the polymer spinning solution through an electrospinning machine with a single needle or multiple needles at a flow rate of 1-6 mL / h, applying an electric field voltage of -10-30 kV, and spinning for 5-60 minutes to obtain a polymer base layer;

[0022] Step 2: dilute the carboxymethyl cellulose with water to form a carboxymethyl cellulose spinning solution with a mass concentration of 1-10%, and place the carboxymethyl cellulose spinning solution and the polymer spinning solution prepared in step 1 in an alternate manner. Set the liquid feeding speed to 5-60mL / h, apply an electric field voltage of -10-30kV, and spin for 5-30min to form a mixed fiber layer on the surface of the polymer base layer by electrospinning.

[0023] Step 3: Add the carboxymethyl cellulose spinning solution prepared in step 2 into the injector, set the liquid feeding rate to 5-60 mL / h, apply the electric field voltage of -10-30 kV, and electrospin for 0.5-5 minutes to form a gel layer on the surface of the mixed fiber layer.

[0024] In the method for preparing the composite multi-layer anti-adhesion film, the biodegradable high molecular polymer is polylactic acid PLA or polylactic acid-glycolic acid copolymer PLGA, and the organic solvent is acetone or dichloromethane.

[0025] The present invention further provides a method for preparing a composite multi-layer anti-adhesion film, comprising the following steps:

[0026] Step 1: dissolving a biodegradable polymer in an organic solvent to obtain a polymer spinning solution with a mass concentration of 5%-30%, extruding the polymer spinning solution through an electrospinning machine with a single needle or multiple needles at a flow rate of 1-6 mL / h, applying an electric field voltage of -10-30 kV, and spinning for 5-60 minutes to obtain a polymer base layer;

[0027] Step 2: diluting carboxymethyl cellulose with water to form a carboxymethyl cellulose spinning solution with a mass concentration of 1-10%, then configuring the carboxymethyl cellulose spinning solution and the polymer spinning solution prepared in step 1 to form an electrospinning W / O emulsion, extruding the electrospinning W / O emulsion through an electrospinning machine with a single needle or multiple needles, setting the liquid flow rate to 5-60 mL / h, applying an electric field voltage of -10-30 kV, spinning for 5-30 minutes, and electrospinning to form a mixed fiber layer on the surface of the polymer base layer;

[0028] Step 3: Add the carboxymethyl cellulose spinning solution prepared in step 2 into the sample injector, extrude the carboxymethyl cellulose spinning solution through an electrospinning machine with a single needle or multiple needles, set the liquid feeding speed to 5-60 mL / h, apply an electric field voltage of -10-30 kV, and electrospin for 0.5-5 minutes to form a gel layer on the surface of the mixed fiber layer.

[0029] In the method for preparing the composite multi-layer anti-adhesion film, the biodegradable high molecular polymer is polylactic acid PLA or polylactic acid-glycolic acid copolymer PLGA, and the organic solvent is acetone or dichloromethane.

[0030] The composite multilayer anti-adhesion membrane of the present invention comprises a loose carboxymethyl cellulose layer on one side and a mixed fiber layer composed of a biodegradable polymer and carboxymethyl cellulose in the middle layer. The membrane has a loose porous structure and contains carboxymethyl cellulose and biodegradable polymer. Carboxymethyl cellulose is a hydrophilic cellulose that absorbs body fluids upon contact with body fluids to form a gel-like substance, which can adhere well to the wound, thus overcoming the defect of pure polymer anti-adhesion products that are difficult to adhere to tissues and require additional suturing and fixation. The mixture of biodegradable polymer and carboxymethyl cellulose can prevent the carboxymethyl cellulose from being diluted too quickly by body fluids, allowing it to maintain a stable concentration and amount at the injury site. The higher pore size can guide fibroblasts to grow into and fix the anti-adhesion membrane. The other side is a relatively dense polymer base layer, which has a lower pore size to prevent fibroblasts from passing through, thereby achieving an anti-adhesion effect.

[0031] At the initial stage of implantation, carboxymethyl cellulose forms a gel in the body, providing initial adhesion to allow the anti-adhesion membrane to adhere to the tissue. The carboxymethyl cellulose in the mixed fiber layer is gradually absorbed by the human body to form a high-molecular polymer layer with larger pores, which enables fibroblasts to grow along the pores into the membrane, accelerate wound healing, and allow the anti-adhesion membrane to always be fixed to the tissue.

[0032] The other side is a pure high molecular polymer base layer with a pore size smaller than the diameter of fibroblasts, which can not only provide strength support but also provide anti-adhesion effect.

[0033] The composite anti-adhesion membrane of the present invention not only combines the high mechanical strength and long residence time of pure polymer anti-adhesion membranes, but also provides better anti-adhesion effects. During the initial stage of lamination, the surface carboxymethyl cellulose provides initial adhesion, allowing the anti-adhesion membrane to adhere tightly to the wound and surrounding tissues, preventing movement of the isolation membrane. The carboxymethyl cellulose also absorbs leakage from the anastomosis, preventing the leakage of other body fluids and fibrinogen, and enhancing the anti-adhesion effect after surgery.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The composite multi-layer anti-adhesion membrane of the present invention has a simple preparation process, and the composite multi-layers are all prepared using the same process. The present invention prepares a composite membrane with carboxymethyl cellulose and a biodegradable high molecular polymer. The surface carboxymethyl cellulose contacts the damaged tissue to provide initial adhesion so that the membrane is tightly attached to the tissue, avoiding movement of the isolation membrane and leakage of the anastomosis, effectively stopping bleeding and preventing other body fluids and fibrinogen from seeping out. The gradual dissolution of the carboxymethyl cellulose in the mixed fiber layer avoids the carboxymethyl cellulose from being diluted too quickly and absorbed by the body, making it difficult to maintain a stable concentration and amount at the damaged site for a long time. As the carboxymethyl cellulose in the mixed fiber layer is gradually diluted and absorbed, the remaining loose high molecular polymer structure can guide fibroblasts to grow into the membrane, promote wound healing, and keep the anti-adhesion membrane fixed on the tissue at all times. The high molecular polymer base layer on the other side has a dense structure that can effectively prevent fibroblasts from breaking through the anti-adhesion membrane, providing an anti-adhesion effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of the composite multi-layer anti-adhesion film of the present invention;

[0037] Figure 2 It is an experimental model for evaluating the effectiveness of polymer base layers and hybrid fiber layers;

[0038] Figure 3 is a micrograph of the bottom of the 24-well plate of Example 6 on day 3;

[0039] Figure 4 This is a micrograph of the bottom of the 24-well plate of Example 5 on day 14. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to the embodiments. It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0042] like Figure 1As shown, the composite multi-layer anti-adhesion membrane of the present invention sequentially comprises a polymer base layer 3 composed of a biodegradable polymer, a mixed fiber layer 2 formed on the surface of the polymer base layer 3, and a gel layer 1 formed on the surface of the mixed fiber layer 2;

[0043] The material of the gel layer 1 is carboxymethyl cellulose, and the thickness of the gel layer 1 is 0.001-0.03 mm;

[0044] The material of the mixed fiber layer 2 is a mixed fiber composed of a biodegradable polymer and carboxymethyl cellulose, the mass ratio of the biodegradable polymer to the carboxymethyl cellulose is 0.5-5:1, the layer thickness of the mixed fiber layer is 0.01-0.1 mm, and the pore size is 60-250 μm;

[0045] The pore size of the high molecular polymer base layer 3 is ≤ 20 μm, the porosity is > 70%, and the thickness of the high molecular polymer base layer 3 is 0.01-0.03 mm;

[0046] The molecular weight of carboxymethyl cellulose is 250-1000 kDa.

[0047] The biodegradable high molecular polymer is polylactic acid PLA or polylactic acid-glycolic acid copolymer PLGA.

[0048] The raw materials used in this embodiment are all commercially available products.

[0049] Example 1

[0050] Poly(lactic acid-co-glycolic acid) copolymer (PLGA) (the molar ratio of glycolide monomer to lactide monomer is 1:1) was prepared. The specific preparation steps are as follows:

[0051] Take 116 grams of glycolide and 144 grams of lactide and place them in a dried flask, add 0.78 mL of initiator and 2.6 mL of catalyst, evacuate and react at 60°C for 2 hours, then heat to a molten state, and continue to react at 120°C for 40 hours. After the reaction is completed, take out and add 1.5 L of dichloromethane to dissolve. After the dissolution is complete, pour into alcohol to precipitate, wash several times, put into a vacuum oven and dry at 25-60°C for 12 hours to obtain polylactic acid-glycolic acid copolymer PLGA for use.

[0052] The preparation method of the composite multi-layer anti-adhesion film of this embodiment comprises the following specific steps:

[0053] Step 1: Weigh 30 g of poly(lactic acid-co-glycolic acid) copolymer (PLGA), add 220 g of dichloromethane as a solvent to prepare a polymer spinning solution, add the polymer spinning solution into the injector, set the liquid feeding rate to 1.2 mL / h, apply an electric field voltage of 12 kV, and spin with a multi-needle for 40 min to obtain a polymer base layer.

[0054] Step 2: Add 97 grams of purified water into a mixing tank with a stirring device. While turning on the stirring device, slowly and evenly sprinkle 3 grams of carboxymethyl cellulose into the mixing tank and stir continuously to completely blend and dissolve the carboxymethyl cellulose and water. When the carboxymethyl cellulose is evenly dispersed in the water and no obvious large lumps exist, stop stirring and allow it to penetrate and blend with the water in a static state to obtain a carboxymethyl cellulose spinning solution for use.

[0055] 0.3 g of emulsifier (Span-80) was added to 20 g of dichloromethane, and 100 g of carboxymethyl cellulose spinning solution was added under high-speed stirring. Then, 15 g of poly(lactic-co-glycolic acid) copolymer (PLGA) and 30 g of hexafluoroisopropanol were added. The mixture was stirred vigorously for 4 hours. When the solution was uniform, the electrospun W / O emulsion was obtained.

[0056] The electrospun W / O emulsion was electrospun on a high molecular polymer base layer, the liquid feeding speed was set to 28 mL / h through a multi-needle head, an electric field voltage of 25 kV was applied, and the spinning was performed for 5 minutes to form a mixture fiber layer on the upper surface of the high molecular polymer base layer.

[0057] Step 3: Add the carboxymethyl cellulose spinning solution prepared in step 2 into the injector, set the liquid feeding rate to 5 mL / h through the multi-needle head, apply an electric field voltage of 30 kV, and spin for 0.5 min to form a carboxymethyl cellulose gel layer on the upper surface of the mixed fiber layer.

[0058] Step 4: The obtained finished product is vacuum dried for 18 hours.

[0059] Example 2

[0060] Preparation of polylactic acid PLA, the specific preparation steps are as follows:

[0061] Take 200 grams of lactide and place it in a dried flask, add 0.6 mL of initiator and 2 mL of catalyst, react at 80 ° C for 3 hours after vacuuming, heat to a molten state, and continue to react at 130 ° C for 12 hours. After the reaction is completed, take it out and add 1 L of ethyl acetate to dissolve it. After the dissolution is complete, pour it into alcohol for precipitation, wash it several times, put it into a vacuum oven and dry it at 35 ° C for 12 hours to obtain polylactic acid PLA for use.

[0062] The preparation method of the composite multi-layer anti-adhesion film of this embodiment comprises the following specific steps:

[0063] Step 1: Weigh 30 grams of polylactic acid (PLA), add 220 grams of acetone as a solvent to prepare a polymer spinning solution, add the polymer spinning solution into the injector, set the liquid feeding rate to 1.2 mL / h, apply an electric field voltage of 12 kV, and spin with a multi-needle for 40 minutes to obtain a polymer base layer.

[0064] Step 2: Add 99 grams of purified water into a mixing tank with a stirring device. While turning on the stirring device, slowly and evenly sprinkle 1 gram of carboxymethyl cellulose into the mixing tank and stir continuously to completely blend and dissolve the carboxymethyl cellulose and water. When the carboxymethyl cellulose is evenly dispersed in the water and no obvious large lumps exist, stop stirring and allow it to penetrate and blend with the water in a static state to obtain a carboxymethyl cellulose spinning solution for use.

[0065] 0.1 g of emulsifier (Span-80) was added to 20 g of dichloromethane, and 100 g of carboxymethyl cellulose spinning solution was added under high-speed stirring. Then, 5 g of polylactic acid (PLA) and 10 g of hexafluoroisopropanol were added and stirred vigorously for 3 hours. When the solution was uniform, the electrospinning W / O emulsion was obtained.

[0066] The electrospun W / O emulsion was electrospun on a high molecular polymer base layer, the liquid feeding speed was set to 28 mL / h through a multi-needle head, an electric field voltage of 25 kV was applied, and the spinning was performed for 5 minutes to form a mixture fiber layer on the upper surface of the high molecular polymer base layer.

[0067] Step 3: Add the carboxymethyl cellulose spinning solution prepared in step 2 into the injector, set the liquid feeding rate to 5 mL / h through the multi-needle head, apply an electric field voltage of 30 kV, and spin for 0.5 min to form a carboxymethyl cellulose gel layer on the upper surface of the mixed fiber layer.

[0068] Step 4: The obtained finished product is vacuum dried for 18 hours.

[0069] Example 3

[0070] Poly(lactic acid-co-glycolic acid) copolymer (PLGA) (the molar ratio of glycolide monomer to lactide monomer is 1:1) was prepared. The specific preparation steps are as follows:

[0071] Take 116 grams of glycolide and 144 grams of lactide and place them in a dried flask, add 0.78 mL of initiator and 2.6 mL of catalyst, evacuate and react at 60°C for 2 hours, then heat to a molten state, and continue to react at 120°C for 40 hours. After the reaction is completed, take out and add 1.5 L of dichloromethane to dissolve. After the dissolution is complete, pour into alcohol to precipitate, wash several times, put into a vacuum oven and dry at 25-60°C for 12 hours to obtain polylactic acid-glycolic acid copolymer PLGA for use.

[0072] The preparation method of the composite multi-layer anti-adhesion film of this embodiment comprises the following specific steps:

[0073] Step 1: Weigh 30 g of poly(lactic acid-co-glycolic acid) copolymer (PLGA), add 220 g of dichloromethane as a solvent to prepare a polymer spinning solution, add the polymer spinning solution into the injector, set the liquid feeding rate to 1.2 mL / h, apply an electric field voltage of 12 kV, and spin with a multi-needle for 40 min to obtain a polymer base layer.

[0074] Step 2: Add 98 grams of purified water into a mixing tank with a stirring device. While turning on the stirring device, slowly and evenly sprinkle 2 grams of carboxymethyl cellulose into the mixing tank and stir continuously to completely blend and dissolve the carboxymethyl cellulose and water. When the carboxymethyl cellulose is evenly dispersed in the water and no obvious large lumps exist, stop stirring and allow it to penetrate and blend with the water in a static state to obtain a carboxymethyl cellulose spinning solution for use.

[0075] The high molecular weight polymer spinning solution prepared in step 1 is added to the injector, and the carboxymethyl cellulose spinning solution is placed in another injector. The two injectors are placed alternately, the liquid feeding rate is set to 12 mL / h, the electric field voltage is applied to 25 kV, and the spinning is performed for 5 minutes. A double-layer or multi-layer composite membrane, i.e., a mixture fiber layer, is formed on the upper surface of the high molecular weight polymer base layer by electrospinning.

[0076] Step 3: Close the polymer spinning solution injector, keep the solution feeding speed, distance, and electric field voltage unchanged, and spin for 0.5 minutes to form a carboxymethyl cellulose gel layer on the upper surface of the mixed fiber layer.

[0077] Step 4: The obtained finished product is vacuum dried for 18 hours.

[0078] Example 4

[0079] Preparation of polylactic acid PLA, the specific preparation steps are as follows:

[0080] Take 200 grams of lactide and place it in a dried flask, add 0.6 mL of initiator and 2 mL of catalyst, react at 80 ° C for 3 hours after vacuuming, heat to a molten state, and continue to react at 130 ° C for 12 hours. After the reaction is completed, take it out and add 1 L of ethyl acetate to dissolve it. After the dissolution is complete, pour it into alcohol for precipitation, wash it several times, put it into a vacuum oven and dry it at 35 ° C for 12 hours to obtain polylactic acid PLA for use.

[0081] The preparation method of the composite multi-layer anti-adhesion film of this embodiment comprises the following specific steps:

[0082] Step 1: Weigh 30 grams of polylactic acid (PLA), add 220 grams of acetone as a solvent to prepare a polymer spinning solution, add the polymer spinning solution into the injector, set the liquid feeding rate to 1.2 mL / h, apply an electric field voltage of 12 kV, and spin with a multi-needle for 40 minutes to obtain a polymer base layer.

[0083] Step 2: Add 98 grams of purified water into a mixing tank with a stirring device. While turning on the stirring device, slowly and evenly sprinkle 2 grams of carboxymethyl cellulose into the mixing tank and stir continuously to completely blend and dissolve the carboxymethyl cellulose and water. When the carboxymethyl cellulose is evenly dispersed in the water and no obvious large lumps exist, stop stirring and allow it to penetrate and blend with the water in a static state to obtain a carboxymethyl cellulose spinning solution for use.

[0084] The high molecular weight polymer spinning solution prepared in step 1 is added to the injector, and the carboxymethyl cellulose spinning solution is placed in another injector. The two injectors are placed alternately, the liquid feeding rate is set to 12 mL / h, the electric field voltage is applied to 25 kV, and the spinning is performed for 5 minutes. A double-layer or multi-layer composite membrane, i.e., a mixture fiber layer, is formed on the upper surface of the high molecular weight polymer base layer by electrospinning.

[0085] Step 3: Close the polymer spinning solution injector, keep the solution feeding speed, distance, and electric field voltage unchanged, and spin for 0.5 minutes to form a carboxymethyl cellulose gel layer on the upper surface of the mixed fiber layer.

[0086] Step 4: The obtained finished product is vacuum dried for 18 hours.

[0087] Comparative Example 1

[0088] The preparation method of the anti-adhesion film of this comparative example comprises the following specific steps:

[0089] Step 1: Weigh 30 grams of polylactic acid (PLA), add 220 grams of acetone as a solvent to prepare a polymer spinning solution, add the polymer spinning solution into the injector, set the liquid feeding rate to 1.2 mL / h, apply an electric field voltage of 12 kV, and spin with a multi-needle for 40 minutes to obtain a polymer base layer.

[0090] Step 2: Add carboxymethyl cellulose spinning solution with a mass concentration of 2% into the sample injector, set the liquid feeding speed to 5 mL / h through the multi-needle head, apply an electric field voltage of 30 kV, and spin for 0.5 min to form a carboxymethyl cellulose gel layer on the upper surface of the polymer base layer.

[0091] In vitro degradation experiment

[0092] The composite multilayer anti-adhesion membranes prepared in Examples 1-4 and the anti-adhesion membrane prepared in Comparative Example 1 were placed in test tubes, 20 mL of pH 7.4 ± 0.3 phosphate buffer was added, and the samples were placed in a constant temperature box at 37 ± 1 ° C for in vitro degradation experiments. After 48 hours, 7 days, and 14 days, the samples in the test tubes were filtered with filter paper, dried, and the mass of the remaining components was weighed. The difference between the mass of the remaining components and the initial mass of the sample as a percentage of the initial mass of the sample was the degradation rate. The experimental results are shown in the following table:

[0093] Table 1 Degradation rates (%) of Examples 1-4 and Comparative Example 1 under different degradation cycles

[0094]

[0095] The mass of carboxymethyl cellulose in the composite multi-layer anti-adhesion films prepared in Examples 1-4 accounts for about 0.5% of the total mass of the films, while the mass of carboxymethyl cellulose in the comparative example accounts for about 0.25% of the total mass of the films.

[0096] The degradation rates of Examples 1-4 gradually increased to the designed mass of carboxymethyl cellulose at 48 hours, 7 days, and 14 days. The degradation rate of the comparative example was close to the designed mass of carboxymethyl cellulose at 48 hours, and the mass loss did not change much at 7 days and 14 days. Comparison of the data of the Examples and Comparative Examples shows that the intermediate layer can slow down the degradation rate of carboxymethyl cellulose and extend the residence time. The fact that the mass of the polymer in the Examples and Comparative Examples did not change much proves the integrity of its structure. The anti-adhesion performance is determined by the structure of the polymer, and different polymer materials have little effect on degradation.

[0097] Example 5

[0098] The high molecular weight polymer spinning solution prepared in Example 1 was added to the injector, the liquid feeding rate was set to 3 mL / h, an electric field voltage of 20 kV was applied, and multi-needle spinning was performed for 30 minutes to obtain a high molecular weight polymer base layer.

[0099] After testing, it was found that the thickness of the high molecular polymer base film was 0.03 mm, the pore size range was 1.6-15.5 μm, and the porosity was 84.32%.

[0100] Example 6

[0101] The high molecular weight polymer spinning solution prepared in step 1 of Example 3 was added to an injector, and the carboxymethyl cellulose spinning solution prepared in step 2 of Example 3 was placed in another injector. The two injectors were placed alternately, the liquid feeding rate was set to 30 mL / h, the electric field voltage was applied to 18 kV, and the spinning was performed for 5 minutes to form a mixture fiber layer by electrospinning.

[0102] After testing, it was found that the membrane thickness of the fiber layer of the mixture was 0.02 mm and the pore size range was 65-200 μm.

[0103] By evaluating the efficacy of the dense layer and the loose layer and simulating the penetration of fibroblasts into the membrane, the barrier function of the high molecular polymer base layer of Example 5 and the space for fibroblasts to grow in the mixture fiber layer of Example 6 were tested in vitro.

[0104] Experimental models such as Figure 2 As shown, a matrix was injected into a 24-well plate, and a prepared test membrane 43 was placed into the wells. The test membrane 43 divided the matrix into an upper matrix layer 41 and a lower matrix layer 42. NIH / 3T3 fibroblasts 44 were seeded into the upper matrix layer, and the nuclei of the NIH / 3T3 fibroblasts 44 were stained with DAPI. Microscopic photographs of the bottom of the 24-well plate were observed on days 3, 7, and 14. Test membrane 43 consisted of the polymer base layer prepared in Example 5 and the mixture fiber layer prepared in Example 6.

[0105] The test results show that: Figure 3 As shown, stained cell nuclei were observed at the bottom of the 24-well plate of Example 6 on the 3rd day, while no cell nuclei were observed at the bottom of the 24-well plate of Example 5 until the 14th day. Figure 4 This is a microscopic photograph of the bottom of the 24-well plate of Example 5 on the 14th day.

[0106] The above experiments confirmed that the barrier function of the high molecular polymer base layer of the present invention and the structure of the mixed fiber layer provide space for fibroblasts to grow inward.

[0107] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the art may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention and should be defined by the claims.

Claims

1. A composite multi-layer anti-adhesion film, characterized in that: The invention sequentially comprises a polymer base layer composed of a biodegradable polymer, a mixed fiber layer formed on the surface of the polymer base layer, and a gel layer formed on the surface of the mixed fiber layer; The material of the gel layer is carboxymethyl cellulose, and the thickness of the gel layer is 0.001-0.03 mm; The mixed fiber layer is made of mixed fibers composed of a biodegradable polymer and carboxymethyl cellulose, the mass ratio of the biodegradable polymer to the carboxymethyl cellulose is 0.5-5:1, the mixed fiber layer has a thickness of 0.01-0.1 mm and a pore size of 60-250 μm; The pore size of the polymer base layer is ≤20 μm, the porosity is >70%, and the thickness of the polymer base layer is 0.01-0.03 mm; The molecular weight of the carboxymethyl cellulose is 250-1000 kDa; The preparation method of the mixed fiber layer comprises: The biodegradable polymer and carboxymethyl cellulose are respectively formed into spinning solutions, and the injection needles are arranged in a staggered manner to obtain the mixed fiber layer by electrospinning; Alternatively, a biodegradable polymer and carboxymethyl cellulose are mixed to form a W / O solution, and then electrospun to form a uniform fiber layer, namely the mixed fiber layer; The biodegradable high molecular polymer is polylactic acid PLA or polylactic acid-glycolic acid copolymer PLGA.

2. A method for preparing the composite multi-layer anti-adhesion film according to claim 1, characterized in that: The following steps are involved: Step 1: dissolving a biodegradable polymer in an organic solvent to obtain a polymer spinning solution with a mass concentration of 5%-30%, extruding the polymer spinning solution through an electrospinning machine with a single needle or multiple needles at a flow rate of 1-6 mL / h, applying an electric field voltage of -10-30 kV, and spinning for 5-60 minutes to obtain a polymer base layer; Step 2: diluting carboxymethyl cellulose with water to form a carboxymethyl cellulose spinning solution with a mass concentration of 1-10%, placing the carboxymethyl cellulose spinning solution and the polymer spinning solution prepared in step 1 alternately on the injector, setting the liquid feeding rate to 5-60 mL / h, applying an electric field voltage of -10-30 kV, spinning for 5-30 minutes, and forming a mixed fiber layer on the surface of the polymer base layer by electrospinning; Step 3: Add the carboxymethyl cellulose spinning solution prepared in step 2 into the injector, set the liquid feeding rate to 5-60 mL / h, apply the electric field voltage of -10-30 kV, and electrospin for 0.5-5 minutes to form a gel layer on the surface of the mixed fiber layer.

3. The method for preparing the composite multi-layer anti-adhesion film according to claim 2, wherein The biodegradable high molecular polymer is polylactic acid PLA or polylactic acid-glycolic acid copolymer PLGA, and the organic solvent is acetone or dichloromethane.

4. A method for preparing the composite multi-layer anti-adhesion film according to claim 1, characterized in that: The following steps are involved: Step 1: dissolving a biodegradable polymer in an organic solvent to obtain a polymer spinning solution with a mass concentration of 5%-30%, extruding the polymer spinning solution through an electrospinning machine with a single needle or multiple needles at a flow rate of 1-6 mL / h, applying an electric field voltage of -10-30 kV, and spinning for 5-60 minutes to obtain a polymer base layer; Step 2: diluting carboxymethyl cellulose with water to form a carboxymethyl cellulose spinning solution with a mass concentration of 1-10%, then configuring the carboxymethyl cellulose spinning solution and the polymer spinning solution prepared in step 1 to form an electrospinning W / O emulsion, extruding the electrospinning W / O emulsion through an electrospinning machine with a single needle or multiple needles, setting the liquid flow rate to 5-60 mL / h, applying an electric field voltage of -10-30 kV, spinning for 5-30 minutes, and electrospinning to form a mixed fiber layer on the surface of the polymer base layer; Step 3: Add the carboxymethyl cellulose spinning solution prepared in step 2 into the sample injector, extrude the carboxymethyl cellulose spinning solution through an electrospinning machine with a single needle or multiple needles, set the liquid feeding speed to 5-60 mL / h, apply an electric field voltage of -10-30 kV, and electrospin for 0.5-5 minutes to form a gel layer on the surface of the mixed fiber layer.

5. The method for preparing the composite multi-layer anti-adhesion film according to claim 4, wherein The biodegradable high molecular polymer is polylactic acid PLA or polylactic acid-glycolic acid copolymer PLGA, and the organic solvent is acetone or dichloromethane.

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