Tissue strengthening material for thoracoabdominal surgery and preparation method thereof

Abstract

The invention relates to the technical field of implantable medical instruments, in particular to a tissue strengthening material for thoracoabdominal surgery and a preparation method of the tissue strengthening material. According to the material, glycerol-lactic acid-glycolic acid hyperbranched polyester is used as a strength supporting layer, acylhydrazone bond-containing pH response antibacterial and anti-inflammatory microcapsules and chitosan-polylactic acid growth factor microcapsules are loaded, and an integrated system is formed through chemical grafting and crosslinking of 1, 4-butanediol diglycidyl ether. Time sequence coordination of mechanical support, preferential release of antibacterial components in an inflammatory environment and subsequent slow release of growth factors is realized. The material degradation path is clear, products are human body metabolizable substances such as lactic acid and glycerol, toxicity risks are avoided, biocompatibility and safety are achieved, the material is suitable for postoperative wound repair such as digestive tract reconstruction and tumor resection, the infection rate can be remarkably reduced, tissue regeneration is accelerated, adhesion is prevented, and an efficient repair scheme is provided for complex surgical operations.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of implantable medical devices, in particular to a tissue reinforcing material for thoraco-abdominal surgery and a preparation method thereof. BACKGROUND

[0002] Tissue repair after thoraco-abdominal surgery faces multiple challenges, including insufficient mechanical support of the wound surface, high risk of postoperative infection, imbalance of inflammatory response regulation, and difficulty in constructing the tissue regeneration microenvironment. The currently widely used degradable materials such as polylactic acid (PLA), polyglycolic acid (PGA) and their copolymer (PLGA) can provide short-term mechanical support, but their linear molecular structure leads to significant defects in the mechanical properties of the materials: the tensile strength and elongation at break are negatively correlated, making it difficult to balance high strength and tissue adhesion. Studies have shown that the degradation rate of PLGA materials in the body fluid environment does not match the tissue regeneration period. Early degradation is too fast, which easily leads to support failure, while excessive cross-linking will prolong the degradation time and cause foreign body reaction risk; in addition, the surface of traditional polyester materials is highly hydrophobic, and the cell adhesion rate is generally low, which seriously limits the directional regeneration of the extracellular matrix.

[0003] In terms of functional improvement, the existing technology mostly uses physical blending method to integrate drug components, but there are problems of burst release effect and uncontrollable release, which cannot meet the continuous anti-infection needs after surgery. The pH-responsive carrier developed in recent years can achieve environment-triggered release, but the single response mechanism cannot adapt to the dynamic changes of the postoperative microenvironment. Studies have shown that the local pH value during the inflammation period can drop to 5.5-6.5, while the repair period rises to 7.2-7.4. The existing carrier system lacks the ability to respond to different pH thresholds, resulting in disorder of the release timing of anti-inflammatory drugs and growth factors.

[0004] These technical bottlenecks seriously restrict the application effect of tissue repair materials in complex dynamic physiological environments. SUMMARY

[0005] The purpose of the present application is to solve the problems existing in the prior art and to provide a tissue reinforcing material for thoraco-abdominal surgery and a preparation method thereof.

[0006] In order to achieve the above purpose, the present application provides a preparation method of a tissue reinforcing material for thoraco-abdominal surgery, comprising the following steps: S1. Under nitrogen protection, glycerol, lactic acid, glycolic acid and p-toluenesulfonic acid were added into a reaction kettle, heated to 100-110℃, stirred for 30-60 min, then heated to 130-140℃, and reduced to 5-10 KPa, reacted for 4-6 h, cooled to room temperature, and then the obtained solid was washed and dried, then added into dichloromethane, stirred for 20-30 min, then poured onto a glass plate, heated to 35-40℃ to volatilize the solvent, and then peeled off to obtain a film, which was washed and dried to obtain a strength support layer material, and the chemical reaction schematic diagram is as follows: Formula (1), glycerol as a branched core, copolymerizes with lactic acid and glycolic acid under the catalysis of p-toluenesulfonic acid to form a hyperbranched copolymer, which has a hyperbranched structure. Compared with traditional linear structure polymers, the hyperbranched copolymer can not only meet the tensile strength of the tissue strengthening material, but also improve the elongation at break, so that it will not be separated due to tissue movement under complex wound, and the hyperbranched structure brings more surface hydroxyl groups, enhances the hydrophilicity of the material, and improves the adhesion rate of tissue cells, so that the tissue cells can grow along the skeleton of the strengthening material, providing a good environment for postoperative rehabilitation; S2. Add oxalyl dihydrazide and deionized water into a reaction container, stir, heat to 70-90℃, then prepare a glycerol aldehyde ethanol solution by adding glycerol aldehyde into ethanol, add the glycerol aldehyde ethanol solution into the reaction container, stir and react for 3-5 h, cool to room temperature, filter, wash and dry the obtained white solid with ethanol / water mixed solution to obtain an acylhydrazone compound, and the chemical reaction equation is as follows: Formula (2), the product is characterized by H NMR, the acylhydrazone bond in the product is easily hydrolyzed and broken under acidic conditions, and is used for subsequent preparation of microcapsule wall material. Under the condition of local tissue pH being acidic due to inflammation in vivo, the acylhydrazone bond is rapidly hydrolyzed and broken to release the antibacterial and anti-inflammatory agent in the core material, so as to sterilize and anti-inflammation the inflammation site and accelerate the healing of the wound; S3. Add the acylhydrazone compound obtained in S2 into deionized water, adjust the pH to 9-11, add sodium periodate, stir at room temperature for 1-3 h, filter and collect the solid, wash and dry to obtain a carboxylated acylhydrazone compound, and the chemical reaction equation is as follows: Formula (3), under alkaline conditions, sodium periodate breaks the C-C bond in the vicinal diol structure of the acylhydrazone compound, oxidizes the hydroxyl group to aldehyde group and further to carboxyl group, and the product is characterized by H NMR; S4. The chitosan-polylactic acid copolymer and soy lecithin are added to dichloromethane, stirred at room temperature for 20-40 min to obtain an oil phase, and then the growth factor is added to deionized water to obtain an aqueous phase. The aqueous phase is poured into the oil phase, and genipin is added. Stirring is carried out at 1000-1500 rpm for 1.5-2.5 h. After drying the volatile solvent, the microcapsules are collected by centrifugation, washed, and freeze-dried to obtain the growth factor microcapsules. Genipin is used as a crosslinking agent to improve the mechanical strength of the microcapsule wall material by crosslinking with chitosan. The chemical reaction schematic diagram is as follows: Formula (4); S5. The carboxylated acylhydrazone compound obtained in S3 is added to a phosphate buffered saline solution, 1-ethyl-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide are added, and stirred for 30-40 min. Then chitosan-polylactic acid copolymer is added, and the temperature is raised to 35-45°C. The reaction is carried out for 3-5 h. After cooling to room temperature, the product is filtered, washed, and dried to obtain the chitosan-polylactic acid-acylhydrazone copolymer. The chemical reaction process schematic diagram is as follows: Formula (5); S6. The chitosan-polylactic acid-acylhydrazone copolymer obtained in S5 and soy lecithin are added to dichloromethane, stirred at room temperature for 20-40 min to obtain an oil phase. Then the antibacterial and anti-inflammatory agent is added to deionized water and stirred for 20-40 min to obtain an aqueous phase. The aqueous phase is poured into the oil phase, and genipin is added. Stirring is carried out at 1000-1500 rpm for 1.5-2.5 h. After drying the volatile solvent, the microcapsules are collected by centrifugation, washed, and freeze-dried to obtain the anti-inflammatory and antibacterial microcapsules. When the wall material is faced with the inflammation that may occur on the postoperative wound surface, the local tissue pH decreases due to inflammation, and the surrounding tissue becomes weakly acidic, which matches the hydrolysis and rupture of the acylhydrazone bond under acidic conditions. The anti-inflammatory and antibacterial microcapsule wall material breaks faster than the growth factor microcapsule, and the anti-inflammatory and antibacterial microcapsule releases the antibacterial and anti-inflammatory agent in the core material first to sterilize and anti-inflammation, and then combines with the growth factor microcapsule to release the growth factor, achieving the purpose of inflammation regulation and tissue regeneration. S7. The strength support layer material obtained in S1 is immersed in a borax buffer solution containing 1,4-butanediol diglycidyl ether, the temperature is raised to 40-45°C, and the reaction is oscillated for 1-2 h. Then it is washed with deionized water, added to a borax buffer solution, and then the growth factor microcapsules obtained in S4 and the anti-inflammatory and antibacterial microcapsules obtained in S6 are added. The temperature is raised to 35-45°C, and the reaction is oscillated for 1-2 h. The product is washed, dried, and obtained as a tissue strengthening material for thoracic and abdominal surgery.

[0007] Preferably, the glycerol, lactic acid, hydroxyacetic acid, p-toluenesulfonic acid, and dichloromethane in S1 are in a weight ratio of 0.1-0.2:2-3:2-3:0.005-0.01:20-30.

[0008] Preferably, the oxalyl dihydrazide, glycerol, deionized water and ethanol in S2 are in a weight ratio of 1:1:8-12:3-7, and the ethanol / water mixed solution refers to a mixture of ethanol and water in a weight ratio of 3:7.

[0009] Preferably, the acylhydrazone compound, sodium periodate and deionized water in S3 are in a weight ratio of 1:1:8-12.

[0010] Preferably, the chitosan-polylactic acid copolymer, soybean lecithin, growth factor, genipin, dichloromethane and deionized water in S4 are in a weight ratio of 2-5:0.5-2:0.01-0.1:0.02-0.2:100:20-50.

[0011] Preferably, the growth factor in S4 is fibroblast growth factor (bFGF).

[0012] Preferably, the carboxylated acylhydrazone compound, chitosan-polylactic acid copolymer, 1-ethyl-(3-dimethylaminopropyl) carbodiimide, N-hydroxysuccinimide and phosphate buffered saline solution in S5 are in a weight ratio of 1:5-10:0.05-0.07:0.05-0.07:80-120.

[0013] Preferably, the phosphate buffered saline solution in S5 has a pH of 7.4.

[0014] Preferably, the chitosan-polylactic acid-acylhydrazone copolymer, soybean lecithin, antibacterial and anti-inflammatory agent, genipin, dichloromethane and deionized water in S6 are in a weight ratio of 2-5:0.5-2:0.1-0.15:0.02-0.2:100:20-50.

[0015] Preferably, the antibacterial and anti-inflammatory agent in S6 refers to a mixture of vancomycin and dexamethasone in a weight ratio of 1:1.

[0016] Preferably, the aforementioned two kinds of microcapsules are prepared by solvent evaporation method, using chitosan-polylactic acid copolymer or modified copolymer containing acylhydrazone bond as wall material, soybean lecithin as emulsifier, dichloromethane as oil phase solvent, and deionized water containing growth factor or antibacterial and anti-inflammatory agent as water phase, dissolving the wall material and soybean lecithin in dichloromethane to form oil phase, dissolving the core material in water to form water phase, pouring the water phase into the oil phase under high-speed stirring, adding genipin crosslinking agent to form stable W / O primary emulsion; then removing dichloromethane by evaporation to make the wall material deposit and wrap the water phase droplets, collecting, washing and freeze-drying to obtain microcapsules with uniform particle size.

[0017] Preferably, the intensity support layer material in S7, the borax buffer containing 1,4-butanediol diglycidyl ether, the borax buffer, the growth factor microcapsule and the anti-bacterial and anti-inflammatory microcapsule are in a weight ratio of 1:10-20:10-20:0.01-0.03:0.02-0.05.

[0018] Preferably, the content of 1,4-butanediol diglycidyl ether in the borax buffer containing 1,4-butanediol diglycidyl ether in S7 is 8-15%.

[0019] Preferably, the pH of the borax buffer in S7 is 9.0.

[0020] Further, the application also provides a tissue strengthening material for thoracic and abdominal surgery, which is prepared by the above preparation method and is used for postoperative tissue repair and strengthening in thoracic and abdominal surgery, provides mechanical support through the intensity support layer material, realizes the integrated treatment of postoperative infection prevention, inflammation control and tissue regeneration through the sequential release of the growth factor microcapsule and the anti-bacterial and anti-inflammatory microcapsule, and is especially suitable for wound repair and adhesion prevention after digestive tract reconstruction and tumor resection.

[0021] The beneficial effects of the application are: 1. The application constructs a three-dimensional hyperbranched polyester network with glycerol as a branched core, and the unique molecular entanglement and branch slip characteristics of the polyester network make the material have high strength and high toughness, which can withstand the dynamic mechanical load of complex wounds in thoracic and abdominal surgery and avoid tearing or separation of the material due to tissue movement. At the same time, the hydroxyl groups on the surface of the hyperbranched structure significantly improve the hydrophilicity of the material, adsorb extracellular matrix proteins through hydrogen bonding, provide an efficient adhesion interface for fibroblasts, promote the ordered growth of cells along the material skeleton, and construct a microenvironment conducive to tissue regeneration, solving the problem of insufficient hydrophilicity and low cell adhesion rate of traditional linear polymers.

[0022] 2. Based on the acid-sensitive characteristics of acylhydrazone bonds, the anti-bacterial and anti-inflammatory microcapsule wall material rapidly hydrolyzes and breaks in the local acidic environment of inflammation, preferentially releasing vancomycin and dexamethasone, and realizing early postoperative infection prevention and inflammation control; and the growth factor microcapsule adopts a non-responsive chitosan-polylactic acid wall material, which continuously releases fibroblast growth factor through polymer degradation in a neutral environment, ensuring stable supply of tissue regeneration signals after inflammation subsides. This two-stage release mechanism of "anti-inflammation first and then repair" avoids the problem of invalid growth factors in the traditional synchronous release mode, improves treatment efficiency and reduces side effects.

[0023] 3. The present application forms a stable three-dimensional chemical network through the covalent cross-linking reaction of the epoxy groups of 1,4-butanediol diglycidyl ether and the hydroxyl groups of hyperbranched polyester, not only significantly improving the mechanical strength and swelling resistance of the material, but also firmly anchoring the microcapsules inside the support layer. Compared with the physical loading method, chemical cross-linking can greatly improve the retention rate of microcapsules, avoiding drug loss due to fluid flushing or material degradation in the physiological environment. At the same time, the adjustable cross-linking density of the material degrades the period and matches the process of tissue regeneration, providing continuous mechanical support while gradually releasing the pore structure to guide the growth of new tissues, realizing the seamless connection of material degradation and functional replacement.

[0024] 4. The present application integrates mechanical support, antibacterial and anti-inflammatory, and growth factor release into a single material system: the hyperbranched polyester backbone provides dynamic mechanical support, the pH-responsive microcapsule precisely controls the inflammation-repair timing, and the chemical cross-linking network guarantees the structural stability. This multi-dimensional synergistic effect can significantly reduce the postoperative infection rate of thoracic and abdominal surgery, reduce adhesion formation, and accelerate wound healing by promoting fibroblast proliferation and collagen deposition. It is especially suitable for complex surgical scenarios such as digestive tract reconstruction and tumor resection, providing a "support-anti-inflammatory-regeneration" integrated solution for clinical practice, breaking through the limitations of traditional materials with single function and disjointed treatment links.

[0025] 5. The material system used in the present application has a clear degradable path and safe metabolic products, ensuring that there is no toxic substance left during the gradual degradation in the body: the hyperbranched copolymer with glycerol, lactic acid, and hydroxyacetic acid as monomers degrades through ester bond hydrolysis, the main products are lactic acid, hydroxyacetic acid, and glycerol, lactic acid is a natural intermediate of human sugar metabolism and can be completely metabolized to CO2 and H2O through the tricarboxylic acid cycle, hydroxyacetic acid can be excreted through the urine or involved in gluconeogenesis, glycerol is an endogenous substance that directly participates in fat metabolism, all of which are non-toxic to the body; chitosan can be degraded into glucosamine and glucose, which are components of the extracellular matrix and have natural biocompatibility; the polylactic acid segment generates lactic acid through ester bond rupture, following the inherent metabolic pathway of the human body; the acylhydrazone bond in the antibacterial microcapsule wall material hydrolyzes into oxalic acid dihydrazide and glycerol in an acidic inflammatory environment, oxalic acid dihydrazide can be further metabolized into carbon dioxide and ammonia, which are excreted through the liver detoxification pathway, and glycerol can be directly utilized by cells or converted into pyruvic acid to enter the metabolic cycle; soy lecithin degrades into glycerol, fatty acids, and choline, all of which are components of cell membranes; genipin, as a natural cross-linking agent, forms stable covalent bonds with chitosan after cross-linking, and its degradation products are low-molecular-weight phenolic compounds, which are excreted after liver metabolism; the 1,4-butanediol diglycidyl ether cross-linking agent generates butanediol and glycerol through ether bond hydrolysis, both of which are non-toxic substances, and butanediol is a commonly used solvent in the cosmetics and pharmaceutical industries, with safety having been widely verified. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 H NMR spectrum of the acylhydrazone compound prepared in Example 2 of the present application; Figure 2 H NMR spectrum of the carboxylated acylhydrazone compound prepared in Example 2 of the present application. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with specific examples.

[0028] The reagent raw materials used in the examples of the present application are as follows: Glycerol was purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., with a purity of 99.7% biotechnology grade; lactic acid was purchased from Jinan Yuno Chemical Co., Ltd., with a purity of food grade; glycolic acid was purchased from Shanghai Melin Biochemical Technology Co., Ltd., with a purity of 98%; p-toluenesulfonic acid was purchased from Shanghai Melin Biochemical Technology Co., Ltd., with a purity of 99%; oxalyl dihydrazide was purchased from Shanghai Bide Pharmaceutical Technology Co., Ltd., with a purity of 98%; glycerol aldehyde was purchased from Shanghai Melin Biochemical Technology Co., Ltd., with a purity of 97%; sodium periodate was purchased from Shanghai Melin Biochemical Technology Co., Ltd., with a purity of 99.5%; chitosan-polylactic acid copolymer was purchased from Xi'an Qiyue Biological Technology Co., Ltd.; soybean lecithin was purchased from Shanghai Melin Biochemical Technology Co., Ltd., with a purity of biotechnology grade; genipin was purchased from Shanghai Melin Biochemical Technology Co., Ltd., with a purity of 98%; phosphate buffered saline solution was purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., with a pH of 7.4; 1-ethyl-(3-dimethylaminopropyl) carbonyldiimide was purchased from Shanghai Melin Biochemical Technology Co., Ltd., with a purity of 98%; N-hydroxy succinimide was purchased from Shanghai Melin Biochemical Technology Co., Ltd., with a purity of biotechnology grade; 1,4-butanediol diglycidyl ether was purchased from Tianjin Xinsisheng Biochemical Technology Co., Ltd., with a purity of 98%; borax buffer was purchased from Shanghai Zolbio Technology Co., Ltd., with a pH of 9.0; fibroblast growth factor was purchased from Hunan Hui Baisheng Biological Technology Co., Ltd., with a purity of 95%; vancomycin was purchased from Hunan Hui Baisheng Biological Technology Co., Ltd., with a purity of 98%; dexamethasone was purchased from Hunan Hui Baisheng Biological Technology Co., Ltd., with a purity of 99%.

[0029] Example 1: A specific preparation method of a tissue reinforcing material for thoraco-abdominal surgery, comprising the following steps: (1) Under nitrogen protection, 5 g glycerol, 100 g lactic acid, 100 g glycolic acid and 0.25 g p-toluenesulfonic acid were added into a reaction kettle, and stirred for 30 min after being heated to 100°C, then heated to 130°C and reduced to 5 KPa, and reacted for 4 h. After being cooled to room temperature, the obtained solid was washed and dried, and then added into 1000 g dichloromethane, stirred for 20 min, then poured on a glass plate, and the solvent was evaporated after being heated to 35°C, and then the film was peeled off, and the film was washed and dried to obtain a strength support layer material; (2) 10 g oxalyl dihydrazide and 80 g deionized water were added into a reaction container, and stirred, and then heated to 70°C. 10 g glycerol aldehyde was added into 30 g ethanol to prepare a glycerol aldehyde ethanol solution, and the glycerol aldehyde ethanol solution was added into the reaction container, and stirred and reacted for 3 h. After being cooled to room temperature, filtration was performed, and the obtained white solid was washed and dried with an ethanol / water mixed solution (ethanol and water were mixed in a weight ratio of 3:7) to obtain an acylhydrazone compound; (3) 8 g of the acylhydrazone compound obtained in (2) was added into 64 g deionized water, and the pH was adjusted to 9. 8 g sodium periodate was added, and stirred and reacted at room temperature for 1 h. The solid was collected by filtration, and washed and dried to obtain a carboxylated acylhydrazone compound; (4) 2 g chitosan-polylactic acid copolymer and 0.5 g soybean lecithin were added into 100 g dichloromethane, and stirred at room temperature for 20 min to obtain an oil phase. 0.01 g bFGF was added into 20 g deionized water to obtain an aqueous phase, and the aqueous phase was poured into the oil phase, and 0.02 g genipin was added. Stirring was performed at 1000 rpm for 1.5 h, and the volatile solvent was dried. The microcapsules were collected by centrifugation, washed, and freeze-dried to obtain growth factor microcapsules; (5) 5 g of the carboxylated acylhydrazone compound obtained in (3) was added into 400 g phosphate buffered saline solution, and 0.25 g 1-ethyl-(3-dimethylaminopropyl) carbonyl diimide and 0.25 g N-hydroxysuccinimide were added, and stirred for 30 min. Then 25 g chitosan-polylactic acid copolymer was added, and heated to 35°C, and reacted for 3 h. After being cooled to room temperature, filtration, washing and drying were performed to obtain chitosan-polylactic acid-acylhydrazone copolymer; (6) 5 g of the chitosan-polylactic acid-acylhydrazone copolymer obtained in (5) and 1.25 g soybean lecithin were added into 250 g dichloromethane, and stirred at room temperature for 20 min to obtain an oil phase. 0.25 g of an antibacterial and anti-inflammatory agent (vancomycin and dexamethasone were mixed in a weight ratio of 1:1) was added into 50 g deionized water, and stirred for 20 min to obtain an aqueous phase. The aqueous phase was poured into the oil phase, and 0.05 g genipin was added. Stirring was performed at 1000 rpm for 1.5 h, and the volatile solvent was dried. The microcapsules were collected by centrifugation, washed, and freeze-dried to obtain anti-inflammatory and antibacterial microcapsules; (7) 100 g of the strength supporting layer material obtained in (1) was immersed in 1000 g of a borax buffer solution containing 80 g of 1,4-butanediol diglycidyl ether, and the temperature was raised to 40°C, and the reaction was carried out with shaking for 1 h. Then, after washing with deionized water, 1000 g of a borax buffer solution was added, and 1 g of the growth factor microcapsules obtained in (4) and 2 g of the anti-inflammatory and antibacterial microcapsules obtained in (6) were added, and the temperature was raised to 35°C, and the reaction was carried out with shaking for 1 h. After washing and drying, a tissue strengthening material for thoracic and abdominal surgery was obtained.

[0030] Example 2: A specific preparation method of a tissue strengthening material for thoracic and abdominal surgery, comprising the following steps: (1) 5 g of glycerol, 83 g of lactic acid, 83 g of glycolic acid, and 0.27 g of p-toluenesulfonic acid were added to a reaction kettle under nitrogen protection, and the temperature was raised to 105°C, and stirred for 45 min. Then, the temperature was raised to 135°C, and the pressure was reduced to 7 KPa, and the reaction was carried out for 5 h. After cooling to room temperature, the obtained solid was washed and dried, and then added to 833 g of dichloromethane, stirred for 25 min, and then poured onto a glass plate. After evaporating the solvent at a temperature of 37°C, the film was peeled off, washed, and dried to obtain a strength supporting layer material; (2) 3 g of oxalyl dihydrazide and 30 g of deionized water were added to a reaction vessel, and stirred, and the temperature was raised to 80°C. Then, 3 g of glycerol aldehyde was added to 15 g of ethanol to prepare a glycerol aldehyde ethanol solution, which was added to the reaction vessel. The reaction was carried out with stirring for 4 h, and after cooling to room temperature, the white solid was filtered, washed with an ethanol / water mixed solution (prepared by mixing ethanol and water in a weight ratio of 3:7), and dried to obtain an acylhydrazone compound; (3) 3 g of the acylhydrazone compound obtained in (2) was added to 30 g of deionized water, and the pH was adjusted to 10. Then, 3 g of sodium periodate was added, and the reaction was carried out with stirring at room temperature for 2 h. The solid was collected by filtration, washed, and dried to obtain a carboxylated acylhydrazone compound; (4) 5 g of chitosan-polylactic acid copolymer and 1.9 g of soybean lecithin were added to 125 g of dichloromethane, and stirred at room temperature for 30 min to obtain an oil phase. Then, 0.07 g of bFGF was added to 37.5 g of deionized water to obtain an aqueous phase. The aqueous phase was poured into the oil phase, and 0.015 g of genipin was added. The stirring was carried out at 1200 rpm for 2 h. After drying and evaporating the solvent, the microcapsules were collected by centrifugation, washed, and freeze-dried to obtain growth factor microcapsules; (5) 1.25 g of the carboxylated acylhydrazone compound obtained in (3) was added to 125 g of a phosphate buffered saline solution, 0.075 g of l-ethyl-(3-dimethylaminopropyl) carbodiimide and 0.075 g of N-hydroxysuccinimide were added, stirred for 35 min, then 10 g of chitosan-polylactic acid copolymer was added, warmed to 40 °C, reacted for 4 h, after cooling to room temperature, filtered, washed, dried to obtain chitosan-polylactic acid-acylhydrazone copolymer; (6) 10 g of the chitosan-polylactic acid-acylhydrazone copolymer obtained in (5) and 3.75 g of soybean lecithin were added to 250 g of dichloromethane, stirred at room temperature for 30 min to obtain an oil phase, then 0.3 g of an antibacterial and anti-inflammatory agent (vancomycin and dexamethasone mixed at a weight ratio of 1:1) was added to 100 g of deionized water, stirred for 30 min to obtain an aqueous phase, the aqueous phase was poured into the oil phase, and 0.25 g of genipin was added, stirred at 1250 rpm for 2 h, after drying the volatile solvent, the microcapsules were collected by centrifugation, washed, and freeze-dried to obtain anti-inflammatory and antibacterial microcapsules; (7) 100 g of the strength support layer material obtained in (1) was immersed in 1500 g of a borate buffer solution containing 120 g of 1,4-butanediol diglycidyl ether, warmed to 43 °C, and oscillated for 1.5 h, then washed with deionized water, added to 1500 g of a borate buffer solution, then added 2 g of the growth factor microcapsules obtained in (4) and 4 g of the anti-inflammatory and antibacterial microcapsules obtained in (6), warmed to 40 °C, oscillated for 1.5 h, the product was washed, dried to obtain a tissue strengthening material for thoracic and abdominal surgery.

[0031] Example 3: A specific preparation method of a tissue strengthening material for thoracic and abdominal surgery, comprising the following steps: (1) Under nitrogen protection, 5 g of glycerol, 75 g of lactic acid, 75 g of 0 hydroxyacetic acid and 0.25 g of p-toluenesulfonic acid were added to a reaction kettle, warmed to 110 °C, stirred for 60 min, then warmed to 140 °C, and reduced to 10 KPa, reacted for 6 h, cooled to room temperature, the obtained solid was washed, dried and added to 750 g of dichloromethane, stirred for 30 min, then poured onto a glass plate, warmed to 40 °C to volatilize the solvent, then peeled off to obtain a film, the film was washed, dried to obtain a strength support layer material; (2) 2 g of oxalic acid dihydrazide and 24 g of deionized water were added to a reaction vessel, stirred, warmed to 90 °C, then 2 g of glyceraldehyde was added to 14 g of ethanol to prepare a glyceraldehyde ethanol solution, the glyceraldehyde ethanol solution was added to the reaction vessel, stirred and reacted for 5 h, cooled to room temperature, filtered, the obtained white solid was washed with an ethanol / water mixed solution (ethanol and water were mixed at a weight ratio of 3:7), dried to obtain an acylhydrazone compound; (3) 2 g of the acylhydrazone compound obtained in (2) was added to 24 g of deionized water, the pH was adjusted to 11, 2 g of sodium periodate was added, and the reaction was stirred at room temperature for 3 h. The solid was collected by filtration, washed, and dried to obtain a carboxylated acylhydrazone compound; (4) 5 g of chitosan-polylactic acid copolymer and 2 g of soybean lecithin were added to 100 g of dichloromethane, stirred at room temperature for 40 min to obtain an oil phase. 0.1 g of bFGF was added to 50 g of deionized water to obtain an aqueous phase. The aqueous phase was poured into the oil phase, and 0.2 g of genipin was added. The mixture was stirred at 1500 rpm for 2.5 h. After the volatile solvent was dried, the microcapsules were collected by centrifugation, washed, and freeze-dried to obtain growth factor microcapsules; (5) 1 g of the carboxylated acylhydrazone compound obtained in (3) was added to 120 g of phosphate buffered saline solution, 0.07 g of 1-ethyl-(3-dimethylaminopropyl) carbonyl diimide and 0.07 g of N-hydroxysuccinimide were added, and the mixture was stirred for 40 min. Then 10 g of chitosan-polylactic acid copolymer was added, and the reaction was carried out at 45°C for 5 h. After cooling to room temperature, the product was filtered, washed, and dried to obtain a chitosan-polylactic acid-acylhydrazone copolymer; (6) 10 g of the chitosan-polylactic acid-acylhydrazone copolymer obtained in (5) and 4 g of soybean lecithin were added to 200 g of dichloromethane, and the mixture was stirred at room temperature for 40 min to obtain an oil phase. Then 0.3 g of an antibacterial and anti-inflammatory agent (a mixture of vancomycin and dexamethasone at a weight ratio of 1:1) was added to 100 g of deionized water, and the mixture was stirred for 40 min to obtain an aqueous phase. The aqueous phase was poured into the oil phase, and 0.4 g of genipin was added. The mixture was stirred at 1500 rpm for 2.5 h. After the volatile solvent was dried, the microcapsules were collected by centrifugation, washed, and freeze-dried to obtain anti-inflammatory and antibacterial microcapsules; (7) 100 g of the strength support layer material obtained in (1) was immersed in 2000 g of borax buffer solution containing 300 g of 1,4-butanediol diglycidyl ether, and the reaction was carried out at 45°C for 2 h. After washing with deionized water, the product was added to 2000 g of borax buffer solution, and 3 g of growth factor microcapsules obtained in (4) and 5 g of anti-inflammatory and antibacterial microcapsules obtained in (6) were added. The reaction was carried out at 45°C for 2 h. After washing and drying, a tissue strengthening material for thoracic and abdominal surgery was obtained.

[0032] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that the wall material of the growth factor microcapsules is also made of chitosan-polylactic acid-acylhydrazone copolymer. The specific preparation method is as follows: a specific preparation method of a tissue strengthening material for thoracic and abdominal surgery, comprising the following steps: (1) Under nitrogen protection, 5 g of glycerol, 83 g of lactic acid, 83 g of glycolic acid and 0.27 g of p-toluenesulfonic acid were added into a reaction kettle, and the temperature was raised to 105°C, and stirred for 45 min, then the temperature was raised to 135°C, and the pressure was reduced to 7 KPa, and reacted for 5 h, and then cooled to room temperature, the obtained solid was washed and dried, and then added into 833 g of dichloromethane, stirred for 25 min, then poured on a glass plate, the solvent was evaporated by raising the temperature to 37°C, and then the film was peeled off, and then washed and dried to obtain a strong support layer material; (2) 3 g of oxalic acid dihydrazide and 30 g of deionized water were added into a reaction container, and stirred, and then the temperature was raised to 80°C, and then 3 g of glycerol aldehyde was added into 15 g of ethanol to prepare a glycerol aldehyde ethanol solution, and then the glycerol aldehyde ethanol solution was added into the reaction container, and stirred and reacted for 4 h, and then cooled to room temperature, and filtered, and then the obtained white solid was washed and dried with an ethanol / water mixed solution (ethanol and water were mixed in a weight ratio of 3:7) to obtain an acylhydrazone compound; (3) 3 g of the acylhydrazone compound obtained in (2) was added into 30 g of deionized water, and the pH was adjusted to 10, and then 3 g of sodium periodate was added, and stirred and reacted at room temperature for 2 h, and then the solid was collected by filtration, and then washed and dried to obtain a carboxylated acylhydrazone compound; (4) 1.88 g of the carboxylated acylhydrazone compound obtained in (3) was added into 187.5 g of a phosphate buffered saline solution, and then 0.113 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide and 0.113 g of N-hydroxysuccinimide were added, and stirred for 35 min, and then 15 g of chitosan-polylactic acid copolymer was added, and the temperature was raised to 40°C, and reacted for 4 h, and then cooled to room temperature, and filtered, washed and dried to obtain a chitosan-polylactic acid-acylhydrazone copolymer; (5) 5 g of the chitosan-polylactic acid-acylhydrazone copolymer obtained in (4) and 1.9 g of soybean lecithin were added into 125 g of dichloromethane, and stirred at room temperature for 30 min to obtain an oil phase, and then 0.07 g of bFGF was added into 37.5 g of deionized water to obtain an aqueous phase, and then the aqueous phase was poured into the oil phase, and 0.015 g of genipin was added, and stirred at 1200 rpm for 2 h, and then the volatile solvent was dried, and the microcapsules were collected by centrifugation, and then washed and freeze-dried to obtain growth factor microcapsules; (6) 10 g of the chitosan-polylactic acid-acylhydrazone copolymer obtained in (4) and 3.75 g of soybean lecithin were added into 250 g of dichloromethane, and stirred at room temperature for 30 min to obtain an oil phase, and then 0.3 g of an antibacterial and anti-inflammatory agent (vancomycin and dexamethasone were mixed in a weight ratio of 1:1) was added into 100 g of deionized water, and stirred for 30 min to obtain an aqueous phase, and then the aqueous phase was poured into the oil phase, and 0.25 g of genipin was added, and stirred at 1250 rpm for 2 h, and then the volatile solvent was dried, and the microcapsules were collected by centrifugation, and then washed and freeze-dried to obtain anti-inflammatory and antibacterial microcapsules; (7) 100 g of the strength support layer material obtained in (1) was immersed in 1500 g of a borax buffer solution containing 120 g of 1,4-butanediol diglycidyl ether, and the temperature was raised to 43°C, and the reaction was carried out for 1.5 h with shaking, and then washed with deionized water, and then added to 1500 g of a borax buffer solution, and then added 2 g of the growth factor microcapsules obtained in (5) and 4 g of the anti-inflammatory and antibacterial microcapsules obtained in (6), and the temperature was raised to 40°C, and the reaction was carried out for 1.5 h with shaking, and then washed and dried to obtain a tissue strengthening material for thoracic and abdominal surgery.

[0033] Comparative Example 2: Comparative Example 2 differs from Example 2 in that the wall material of the growth factor microcapsules and the anti-inflammatory and antibacterial microcapsules is made of chitosan-polylactic acid copolymer, and the specific preparation method is as follows: a specific preparation method of a tissue strengthening material for thoracic and abdominal surgery, comprising the following steps: (1) 5 g of glycerol, 83 g of lactic acid, 83 g of glycolic acid, and 0.27 g of p-toluenesulfonic acid were added to a reaction kettle under nitrogen protection, and the temperature was raised to 105°C, and stirred for 45 min, and then the temperature was raised to 135°C, and the pressure was reduced to 7 KPa, and the reaction was carried out for 5 h, and then cooled to room temperature, and the obtained solid was washed and dried, and then added to 833 g of dichloromethane, and stirred for 25 min, and then poured onto a glass plate, and the solvent was volatilized by raising the temperature to 37°C, and then peeled off to obtain a film, and the film was washed and dried to obtain a strength support layer material; (2) 5 g of chitosan-polylactic acid copolymer and 1.9 g of soybean lecithin were added to 125 g of dichloromethane, and stirred at room temperature for 30 min to obtain an oil phase, and then 0.07 g of bFGF was added to 37.5 g of deionized water to obtain an aqueous phase, and the aqueous phase was poured into the oil phase, and 0.015 g of genipin was added, and stirred at 1200 rpm for 2 h, and then dried to volatilize the solvent, and then centrifuged to collect the microcapsules, and then washed and freeze-dried to obtain growth factor microcapsules; (3) 10 g of chitosan-polylactic acid copolymer and 3.75 g of soybean lecithin were added to 250 g of dichloromethane, and stirred at room temperature for 30 min to obtain an oil phase, and then 0.3 g of an antibacterial and anti-inflammatory agent (vancomycin and dexamethasone mixed in a weight ratio of 1:1) was added to 100 g of deionized water, and stirred for 30 min to obtain an aqueous phase, and the aqueous phase was poured into the oil phase, and 0.25 g of genipin was added, and stirred at 1250 rpm for 2 h, and then dried to volatilize the solvent, and then centrifuged to collect the microcapsules, and then washed and freeze-dried to obtain anti-inflammatory and antibacterial microcapsules; (4) 100 g of the strength support layer material obtained in (1) was immersed in 1500 g of a borax buffer solution containing 120 g of 1,4-butanediol diglycidyl ether, and the temperature was raised to 43°C, and the reaction was stirred for 1.5 h, and then washed with deionized water, and then added to 1500 g of a borax buffer solution, and then added to 2 g of the growth factor microcapsules obtained in (2) and 4 g of the anti-inflammatory and antibacterial microcapsules obtained in (3), and the temperature was raised to 40°C, and the reaction was stirred for 1.5 h, and then the product was washed and dried to obtain a tissue strengthening material for thoracic and abdominal surgery.

[0034] Comparative Example 3: Comparative Example 3 and Example 2 are different in that the strength support layer material is made of a copolymer of lactic acid and glycolic acid, and the specific preparation method is as follows: a specific preparation method of a tissue strengthening material for thoracic and abdominal surgery, comprising the following steps: (1) 120 g of a polylactic acid-glycolic acid copolymer was added to 600 g of dichloromethane, stirred for 25 min, then poured onto a glass plate, the solvent was volatilized at a temperature of 37°C, and then peeled off to obtain a film, and then the film was washed and dried to obtain a strength support layer material; (2) 3 g of oxalyl dihydrazide and 30 g of deionized water were added to a reaction vessel, stirred, and the temperature was raised to 80°C, and then 3 g of glyceraldehyde was added to 15 g of ethanol to prepare a glyceraldehyde ethanol solution, and the glyceraldehyde ethanol solution was added to the reaction vessel, and the reaction was stirred for 4 h, and then cooled to room temperature, filtered, and the white solid obtained was washed with an ethanol / water mixed solution (ethanol and water were mixed in a weight ratio of 3:7) and dried to obtain an acylhydrazone compound; (3) 3 g of the acylhydrazone compound obtained in (2) was added to 30 g of deionized water, the pH was adjusted to 10, 3 g of sodium periodate was added, and the reaction was stirred at room temperature for 2 h, and then the solid was collected by filtration, washed and dried to obtain a carboxylated acylhydrazone compound; (4) 5 g of chitosan-polylactic acid copolymer and 1.9 g of soybean lecithin were added to 125 g of dichloromethane, stirred at room temperature for 30 min to obtain an oil phase, and then 0.07 g of bFGF was added to 37.5 g of deionized water to obtain an aqueous phase, and the aqueous phase was poured into the oil phase, and 0.015 g of genipin was added, and stirred at 1200 rpm for 2 h, and then the solvent was dried, and the microcapsules were collected by centrifugation, washed and freeze-dried to obtain growth factor microcapsules; (5) 1.25 g of the carboxylated acylhydrazone compound obtained in (3) was added to 125 g of a phosphate buffered saline solution, 0.075 g of 1-ethyl-(3-dimethylaminopropyl) carbonyl diimide and 0.075 g of N-hydroxysuccinimide were added, stirred for 35 min, and then 10 g of chitosan-polylactic acid copolymer was added, and the temperature was raised to 40°C, and the reaction was carried out for 4 h, and then cooled to room temperature, filtered, washed and dried to obtain a chitosan-polylactic acid-acylhydrazone copolymer; (6) 10 g of the chitosan-polylactic acid-acylhydrazone copolymer obtained in (5) and 3.75 g of soybean lecithin were added to 250 g of dichloromethane, stirred at room temperature for 30 min to obtain an oil phase, then 0.3 g of an antibacterial and anti-inflammatory agent (vancomycin and dexamethasone were mixed at a weight ratio of 1:1 to prepare) was added to 100 g of deionized water, stirred for 30 min to obtain an aqueous phase, the aqueous phase was poured into the oil phase, and 0.25 g of genipin was added, stirred at 1250 rpm for 2 h, after the volatile solvent was dried, the microcapsules were collected by centrifugation, washed, and then freeze-dried to obtain anti-inflammatory and antibacterial microcapsules; (7) 100 g of the strength support layer material obtained in (1) was immersed in 1500 g of a borax buffer solution containing 120 g of 1,4-butanediol diglycidyl ether, the temperature was raised to 43°C, and the reaction was oscillated for 1.5 h, then after washing with deionized water, 1500 g of a borax buffer solution was added, 2 g of the growth factor microcapsules obtained in (4) and 4 g of the anti-inflammatory and antibacterial microcapsules obtained in (6) were added, the temperature was raised to 40°C, and the reaction was oscillated for 1.5 h, the product was washed, dried, and then a tissue strengthening material for thoracic and abdominal surgery was obtained.

[0035] Comparative Example 4: Comparative Example 4 differs from Example 2 in that 1,4-butanediol diglycidyl ether is not added, and the microcapsules are physically loaded on the strength support layer material, and the specific preparation process is as follows: a specific preparation method of a tissue strengthening material for thoracic and abdominal surgery, comprising the following steps: (1) Under nitrogen protection, 5 g of glycerol, 83 g of lactic acid, 83 g of glycolic acid, and 0.27 g of p-toluenesulfonic acid were added to a reaction kettle, the temperature was raised to 105°C, and stirred for 45 min, then the temperature was raised to 135°C, and the pressure was reduced to 7 KPa, and the reaction was carried out for 5 h, then the obtained solid was washed, dried, and added to 833 g of dichloromethane, stirred for 25 min, then poured onto a glass plate, the temperature was raised to 37°C to volatilize the solvent, and then the film was peeled off, washed, and dried to obtain a strength support layer material; (2) 3 g of oxalyl dihydrazide and 30 g of deionized water were added to a reaction vessel, stirred, and the temperature was raised to 80°C, then 3 g of glycerol aldehyde was added to 15 g of ethanol to prepare a glycerol aldehyde ethanol solution, the glycerol aldehyde ethanol solution was added to the reaction vessel, and the reaction was stirred for 4 h, then the temperature was cooled to room temperature, filtered, and the obtained white solid was washed with an ethanol / water mixed solution (ethanol and water were mixed at a weight ratio of 3:7 to prepare), dried, and then a acylhydrazone compound was obtained; (3) 3 g of the acylhydrazone compound obtained in (2) was added to 30 g of deionized water, the pH was adjusted to 10, 3 g of sodium periodate was added, and the reaction was stirred at room temperature for 2 h, then the solid was collected by filtration, washed, and dried to obtain a carboxylated acylhydrazone compound; (4) 5 g of chitosan-polylactic acid copolymer and 1.9 g of soybean lecithin were added into 125 g of dichloromethane, stirred at room temperature for 30 min to obtain an oil phase, 0.07 g of bFGF was added into 37.5 g of deionized water to obtain an aqueous phase, the aqueous phase was poured into the oil phase, 0.015 g of genipin was added, stirred at 1200 rpm for 2 h, after drying the volatile solvent, the microcapsules were collected by centrifugation, washed, and then freeze-dried to obtain the growth factor microcapsules; (5) 1.25 g of the carboxylated acylhydrazone compound obtained in (3) was added into 125 g of phosphate buffered saline solution, 0.075 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide and 0.075 g of N-hydroxysuccinimide were added, stirred for 35 min, then 10 g of chitosan-polylactic acid copolymer was added, the temperature was raised to 40°C, and reacted for 4 h, after cooling to room temperature, filtration, washing and drying, the chitosan-polylactic acid-acylhydrazone copolymer was obtained; (6) 10 g of the chitosan-polylactic acid-acylhydrazone copolymer obtained in (5) and 3.75 g of soybean lecithin were added into 250 g of dichloromethane, stirred at room temperature for 30 min to obtain an oil phase, then 0.3 g of an antibacterial and anti-inflammatory agent (vancomycin and dexamethasone were mixed in a weight ratio of 1:1) was added into 100 g of deionized water, stirred for 30 min to obtain an aqueous phase, the aqueous phase was poured into the oil phase, and 0.25 g of genipin was added, stirred at 1250 rpm for 2 h, after drying the volatile solvent, the microcapsules were collected by centrifugation, washed, and then freeze-dried to obtain the anti-inflammatory and antibacterial microcapsules; (7) 100 g of the strength support layer material obtained in (1) was laid on a glass plate, 2 g of the growth factor microcapsules obtained in (4) and 4 g of the anti-inflammatory and antibacterial microcapsules obtained in (6) were added into 100 g of deionized water, uniformly sprayed on the strength support layer material, and dried to obtain the tissue reinforcing material for thoracic and abdominal surgery.

[0036] Performance test: 1. Mechanical property test: The tissue reinforcing materials prepared in Examples 1-3 and Comparative Examples 3-4 were cut into strips of 50 mm x 10 mm, a universal material testing machine was used, the tensile speed was set to 5 mm / min at room temperature, and the tensile strength and elongation at break of the materials were tested, and the experimental results are shown in Table 2.

[0037] 2. Cell adhesion rate test: The tissue reinforcing materials prepared in Examples 1-3 and Comparative Examples 3-4 were cut into sizes suitable for 12-well plates, placed in 12-well plates, and inoculated with fibroblast cell suspension at a density of 1 x 10 5The tissue-reinforcing material was removed, washed with a phosphate buffered saline solution, and then dyed with crystal violet for 15 minutes. After being dissolved with anhydrous ethanol, the absorbance value at 595 nm was read by an enzyme-labeled instrument. The absorbance value of Comparative Example 3 was defined as 1, and the cell adhesion rate of Examples 1-3 was calculated. The experimental results are shown in Table 2.

[0038] 3. Degradation time test: The tissue-reinforcing materials prepared in Examples 1-3 and Comparative Examples 3-4 were cut into 50 mm x 10 mm strips and placed in 10 ml of a phosphate buffered saline solution at 37°C and pH = 7.2. The phosphate buffered saline solution was replaced every 5 days, and samples were taken every 7 days. The weight loss rate was calculated by freeze-drying and weighing. The weight loss rate of each sample was recorded, and the experimental results are shown in Table 3.

[0039] 4. pH response test: The tissue-reinforcing materials prepared in Examples 1-3 and Comparative Examples 1-2 were cut into 50 mm x 10 mm strips and immersed in 5 ml of a buffer solution preheated to 37°C at pH = 6 and pH = 7.2, respectively. The release start time T1 and peak concentration time T2 of growth factors and anti-inflammatory and antibacterial components in the buffer solution were detected by HPLC high performance liquid chromatography. The experimental results are shown in Table 4.

[0040] 5. In vivo model experiment: The tissue-reinforcing materials prepared in Examples 1-3 and Comparative Examples 1-4 were divided into 5 groups, with one group serving as a blank control. The blank control was a tissue-reinforcing material made of a commercially available polylactic acid-glycolic acid copolymer. A total of six groups of experiments were conducted, with 8 SPF male mice provided for each group. Acute inflammation was induced by local injection of LPS at the wound site 24 hours before the subsequent surgery. After the mice were anesthetized, the wound site was shaved and disinfected, a 1.5 cm longitudinal incision was made, and the subcutaneous tissue was bluntly separated to form a 2 cm x 2 cm interstice. An appropriately sized tissue-reinforcing material was implanted and sutured to fully adhere to the wound. Three days after the surgery, the wound inflammation was scored according to the standard shown in Table 1: Table 1 Scoring Standard

[0041] The inflammation score of each group of experiments was the average of the sum of the redness range score and the exudate / abscess score of each mouse in the group. Seven days after the surgery, the infection rate of each group of experiments was calculated A wound with pus, odor, or an animal in a state of spiritual decline and refusing to eat was considered infected. Finally, the average wound healing time of each group of experiments was recorded, and the experimental results are shown in Table 5.

[0042] Table 2 Mechanical properties and cell adhesion rate test Table 3 Degradation time test

[0043] Table 4 pH response test

[0044] Table 5 in vivo model experiment

[0045] Performance analysis: From the experimental data in Tables 2-5, it can be seen that the tissue reinforcing material prepared by the present application has good mechanical properties, higher tensile strength to meet the support needs of the reinforcing material, and improved elongation at break to meet the needs of complex lamination; at the same time, the more surface hydroxyl groups brought by the hyperbranched structure improve the hydrophilicity, increase the cell adhesion rate, and make the tissue cells grow along the material skeleton, providing a mechanical framework for tissue repair; compared with traditional poly(lactic-co-glycolic acid), the hyperbranched crosslinked material improves the degradation time, meets the mechanical support needs of the tissue growth stage, and avoids the problem of strength support failure caused by too fast degradation; combined with microcapsules with different release speeds, it can achieve the effect of regulating inflammation first and then promoting growth, avoiding the loss of growth-promoting function of growth factors due to the presence of inflammation; finally, in the in vivo model experiment, it presents the use results of "low inflammation-no infection-fast healing"; among them, the comprehensive performance of Example 2 is the best.

[0046] From the data in Table 2, it can be seen that the tissue reinforcing material prepared by Example 2 has good mechanical properties and cell adhesion rate, which may be because: in the preparation process of Example 2, glycerol is used as a branched core to construct a three-dimensional hyperbranched network, and the hyperbranched structure is crosslinked through the entanglement of molecular chains and the hydrogen bonds of hydroxyl groups, forming a "rigid and flexible" structure. Compared with the linear polymer used in Comparative Example 3, the hyperbranched structure can more evenly disperse stress, improving the toughness while maintaining the strength. In Comparative Example 4, the lack of 1,4-butanediol diglycidyl ether leads to a decrease in tensile strength, which confirms that 1,4-butanediol diglycidyl ether can act as a crosslinking agent to strengthen the material structure; at the same time, the cell adhesion rate of Example 2 is significantly higher than that of the traditional material used in Comparative Example 3, which may be because the hyperbranched polymer prepared in Example 2 has a rich surface hydroxyl group, which can adsorb serum proteins through hydrogen bonding to form a biomimetic interface conducive to cell adhesion. Hydroxyl groups can also improve the hydrophilicity of the material, thereby promoting cell spreading. In Comparative Example 4, due to the physical loading of microcapsules, the uneven loading during the loading process leads to the covering of hydroxyl sites by microcapsules. Although the number of surface hydroxyl groups increases compared to Example 2, the uneven loading shields more hydroxyl sites, resulting in a decrease in the cell adhesion rate of Comparative Example 4.

[0047] As can be seen from the experimental data in Table 3, the degradation period of the reinforcing material prepared in Example 2 is more matched with the tissue regeneration process, and can continuously provide mechanical support for tissue regeneration, which may be because: the adaptability of the degradation period in Example 2 to the tissue regeneration process is derived from the synergistic regulation mechanism of the multi-level molecular structure, the molecular chain entanglement effect generated by the three-dimensional network of the hyperbranched polymer skeleton in the material system, and the stable covalent network constructed by the crosslinking agent, forming a gradient degradation characteristic: in the initial stage, the close intermolecular force maintains the material integrity, providing a rigid support framework for cell migration and tissue reconstruction; with the passage of time, the directional hydrolysis of the main chain ester bond in the neutral environment and the gradual dissociation of the branched node form a dynamic balance, gradually releasing a moderate pore structure, guiding the orderly growth of the new tissue and establishing a mechanical transmission channel, this controllable degradation mode from the surface to the inside and from the local to the whole, not only avoids the early support failure caused by the rapid disintegration of traditional materials, but also prevents the long-term foreign body retention caused by excessive crosslinking, achieving precise matching of the degradation period and the repair process; Comparative Example 3 uses traditional linear polylactic acid-glycolic acid copolymer, which forms a high crystalline region with regular molecular chain arrangement, and water molecules preferentially penetrate along the grain boundary to induce rapid bulk degradation, Comparative Example 4 retains the hyperbranched skeleton but lacks the crosslinking network, and after swelling, the material forms a loose porous structure, the specific surface area increases the rate of ester bond hydrolysis, and the physical adsorption of microcapsules on the material surface forms a stress concentration point, inducing crack propagation to cause non-uniform degradation.

[0048] As can be seen from the data in Table 4, the tissue reinforcing material prepared in Example 2 can achieve the effect of regulating inflammation first and promoting growth later, which may be because: in Example 2, the wall material of the antibacterial microcapsule is constructed by introducing an acylhydrazone bond to form a pH-responsive unit: under the weak acidic conditions of the inflammatory microenvironment, the imine nitrogen atom of the acylhydrazone bond is preferentially protonated, triggering the intramolecular charge distribution reconstruction, leading to the shift of the π electron cloud of the C=N double bond to the nitrogen end, weakening the binding energy with the adjacent carbon atom, and then inducing the rapid rupture of the molecular chain, realizing the rapid release of the antibacterial and anti-inflammatory components, and the wall material of the growth factor microcapsule is designed based on ester bond, and its degradation depends on the nucleophilic attack of water molecules in the neutral environment: the carbonyl oxygen of the ester bond is combined with H2O through hydrogen bonding to form a tetrahedral transition state, followed by slow and gradual hydrolysis, and the release rate is controlled by the kinetics of the bulk degradation of the material; the failure of Comparative Example 1 is due to the confusion of chemical bond functions, and after the growth factor microcapsule is mistakenly introduced into the acylhydrazone bond, the rapid dissociation of its wall material under acidic conditions leads to the premature exposure of the growth factor to the inflammatory environment rich in proteases, and the active ingredients are inactivated by enzymatic hydrolysis, and Comparative Example 2 lacks selectivity due to the single design of the chemical bond, and cannot distinguish the microenvironment difference between the inflammation period and the repair period, leading to the release lag of the antibacterial agent and the disordered release of the growth factor; this hierarchical response system constructed by the intrinsic reactivity of the chemical bond realizes the precise correspondence between the drug release behavior and the biological demand of the tissue repair stage.

[0049] From the data in Table 5, it can be seen that the small mice using the reinforcing material prepared in Example 2 have a "low inflammation-no infection-fast healing" postoperative condition, which may be because: its excellent performance is due to the synergistic effect of its multi-level responsive material system: the gradient degradation network constructed by the hyperbranched polymer skeleton provides sustained mechanical support, and the dual-path microcapsule system realizes precise time release based on the intrinsic characteristics of chemical bonds, the acylhydrazone bond of the antibacterial microcapsule triggers rapid hydrolysis in the inflammatory microenvironment, and the growth factor microcapsule ester bond depends on the neutral environment to release active ingredients, avoiding premature inactivation. In contrast, Comparative Example 1 causes the two components to be released synchronously due to the mismatch of chemical bond functions, anti-inflammatory and regenerative interference, Comparative Example 2 loses environmental response ability due to the single chemical bond, and the release timing is disorderly, Comparative Example 3's linear polymer structure causes degradation rate imbalance, and the mechanical support fails prematurely, and Comparative Example 4 causes microcapsule shedding and material structure disintegration due to the lack of cross-linking; the blank control completely lacks anti-inflammatory and bactericidal and growth factor components, and cannot meet the repair requirements. This multi-dimensional synergistic design of hierarchical regulation of chemical bond reaction activity and material structure is the fundamental reason for Example 2 to achieve precise regulation of the whole process of "infection control-inflammation subsides-tissue regeneration".

[0050] The above description is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing a tissue reinforcement material for thoracic and abdominal surgery, characterized in that, Includes the following steps: S1. Under nitrogen protection, glycerol, lactic acid, glycolic acid and p-toluenesulfonic acid are added to a reaction vessel, heated to 100-110℃ and stirred for 30-60 min, then heated to 130-140℃ and reduced to 5-10 kPa, reacted for 4-6 h, cooled to room temperature, the obtained solid is washed and dried and then added to dichloromethane, stirred for 20-30 min, then poured onto a glass plate, heated to 35-40℃ to evaporate the solvent, peeled off to obtain a film, the film is then washed and dried to obtain a strength support layer material; S2. Add oxalic acid dihydrazide and deionized water to a reaction vessel, stir, and heat to 70-90℃. Then add glyceraldehyde to ethanol to prepare a glyceraldehyde ethanol solution. Add the glyceraldehyde ethanol solution to the reaction vessel, stir and react for 3-5 hours. After cooling to room temperature, filter. The white solid obtained is washed with an ethanol / water mixture and dried to obtain an acylhydrazone compound. S3. Add the acylhydrazone compound obtained in S2 to deionized water, adjust the pH to 9-11, add sodium periodate, stir the reaction at room temperature for 1-3 hours, filter to collect the solid, wash and dry to obtain the carboxylated acylhydrazone compound; S4. Add chitosan-polylactic acid copolymer and soybean lecithin to dichloromethane and stir at room temperature for 20-40 min to obtain an oil phase. Then add growth factor to deionized water to obtain an aqueous phase. Pour the aqueous phase into the oil phase and add genipin. Stir at 1000-1500 rpm for 1.5-2.5 h. After drying and evaporating the solvent, collect the microcapsules by centrifugation, wash, and freeze-dry to obtain growth factor microcapsules. S5. The carboxylated hydrazone compound obtained in S3 is added to a phosphate buffer solution, along with 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide. The mixture is stirred for 30-40 min, then chitosan-polylactic acid copolymer is added. The temperature is raised to 35-45℃, and the reaction is carried out for 3-5 h. After cooling to room temperature, the mixture is filtered, washed, and dried to obtain chitosan-polylactic acid-hydrazone copolymer. S6. Add the chitosan-polylactic acid-hydrazone copolymer and soybean lecithin obtained in S5 to dichloromethane and stir at room temperature for 20-40 min to obtain the oil phase. Then add the antibacterial and anti-inflammatory agent to deionized water and stir for 20-40 min to obtain the aqueous phase. Pour the aqueous phase into the oil phase and add genipin. Stir at 1000-1500 rpm for 1.5-2.5 h. After drying and evaporating the solvent, collect the microcapsules by centrifugation, wash them, and freeze-dry them to obtain the anti-inflammatory and antibacterial microcapsules. S7. Immerse the strength support layer material obtained in S1 in a borax buffer solution containing 1,4-butanediol diglycidyl ether, heat to 40-45℃, and shake for 1-2 hours. Then wash with deionized water, add to the borax buffer solution, and then add the growth factor microcapsules obtained in S4 and the anti-inflammatory and antibacterial microcapsules obtained in S6. Heat to 35-45℃ and shake for 1-2 hours. After washing and drying, the product is used to obtain a tissue reinforcement material for thoracic and abdominal surgery.

2. The method for preparing the tissue reinforcement material for thoracic and abdominal surgery according to claim 1, characterized in that, In S1, glycerol, lactic acid, glycolic acid, p-toluenesulfonic acid, and dichloromethane are present in a weight ratio of 0.1-0.2:2-3:2-3:0.005-0.01:20-30.

3. The method for preparing the tissue reinforcement material for thoracic and abdominal surgery according to claim 1, characterized in that, In S2, oxaloyl hydrazide, glyceraldehyde, deionized water and ethanol are in a weight ratio of 1:1:8-12:3-7. The ethanol / water mixed solution refers to the mixture of ethanol and water in a weight ratio of 3:

7.

4. The method for preparing the tissue reinforcement material for thoracic and abdominal surgery according to claim 1, characterized in that, In S3, the acylhydrazone compound, sodium periodate, and deionized water are in a weight ratio of 1:1:8-12.

5. The method for preparing the tissue reinforcement material for thoracic and abdominal surgery according to claim 1, characterized in that, In S4, the chitosan-polylactic acid copolymer, soybean lecithin, growth factor, genipin, dichloromethane and deionized water are in the following weight ratios: 2-5:0.5-2:0.01-0.1:0.02-0.2:100:20-50, and the growth factor is fibroblast growth factor.

6. The method for preparing the tissue reinforcement material for thoracic and abdominal surgery according to claim 1, characterized in that, In S5, the carboxylated hydrazone compound, chitosan-polylactic acid copolymer, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide, and phosphate buffer solution are present in a weight ratio of 1:5-10:0.05-0.07:0.05-0.07:80-120, and the pH of the phosphate buffer solution is 7.

4.

7. The method for preparing the tissue reinforcement material for thoracic and abdominal surgery according to claim 1, characterized in that, In S6, the chitosan-polylactic acid-hydrazone copolymer, soybean lecithin, antibacterial and anti-inflammatory agent, genipin, dichloromethane and deionized water are mixed in a weight ratio of 2-5:0.5-2:0.1-0.15:0.02-0.2:100:20-50. The antibacterial and anti-inflammatory agent is a mixture of vancomycin and dexamethasone in a weight ratio of 1:

1.

8. The method for preparing the tissue reinforcement material for thoracic and abdominal surgery according to claim 1, characterized in that, The strength support layer material, borax buffer containing 1,4-butanediol diglycidyl ether, borax buffer, growth factor microcapsules, and antibacterial and anti-inflammatory microcapsules in the S7 are in a weight ratio of 1:10-20:10-20:0.01-0.03:0.02-0.

05.

9. The method for preparing the tissue reinforcement material for thoracic and abdominal surgery according to claim 1, characterized in that, The borax buffer solution containing 1,4-butanediol diglycidyl ether in S7 has a content of 8-15% and a pH of 9.

0.

10. A tissue-reinforcing material for thoracic and abdominal surgery, characterized in that, Prepared using the preparation method described in any one of claims 1-9, the tissue strengthening material is formed on the surface of a strength support layer material by chemical grafting of pH-responsive antibacterial and anti-inflammatory microcapsules containing acylhydrazone bonds and growth factor microcapsules embedded in chitosan-polylactic acid. It is used for postoperative tissue repair and strengthening in the thoracic and abdominal cavities. The strength support layer material provides mechanical support, and the sequential release of growth factor microcapsules and antibacterial and anti-inflammatory microcapsules achieves integrated treatment of postoperative infection prevention, inflammation regulation and tissue regeneration. It is suitable for wound repair and adhesion prevention after digestive tract reconstruction and tumor resection.

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