Injectable bone repair composition as well as preparation method and application thereof

Abstract

The invention provides an injectable bone repair composition as well as a preparation method and application thereof. The injectable bone repair composition comprises a mixture and / or reactant of modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure, sulfonated chitosan, a fibrinogen solution and a thrombin solution, thrombin interacts with fibrinogen to form gel in situ, and then the injectable bone repair composition is prepared. The shape of the gel is matched with the edge of a defect notch, and the gel is suitable for repairing damage of various shapes and areas.

Description

Technical Field

[0001] The present invention belongs to the technical field of bone repair materials, and particularly relates to an injectable bone repair composition, a preparation method thereof and an application thereof. Background Art

[0002] With the acceleration of the aging society process, the incidence of bone diseases such as fractures, bone tumors and osteoporosis has increased rapidly. The resulting bone injuries not only seriously threaten the physical and mental health of patients, but also bring a huge economic burden to society. Bone injuries are often accompanied by structural defects, especially in the modern fast-paced life, so bone repair and bone substitute materials with social benefits for the human body have gradually attracted the attention of researchers.

[0003] Autologous bone and allogeneic bone have good osteogenic effects and biocompatibility, but generally have the disadvantages of limited sources, difficult to degrade, potential risks of disease transmission and immune rejection, and longer healing times. In recent years, biomaterials have been increasingly used in the treatment of bone defects and have become a new development trend. Bone repair by implanting a scaffold material is a traditional treatment method. However, the scaffold material needs to be shaped in vitro first, and then cells are adsorbed for transplantation. The operation process is complex, and the stability and use effect in the clinical application are not good. Injectable bone repair materials are a kind of biomedical materials used for local bone defect repair and replacement. Their use can replace traditional complex and time-consuming bone defect treatment methods, such as autologous bone transplantation and allogeneic bone transplantation. Compared with implanting scaffold materials, they also have the advantages of less tissue damage, simple operation, and fewer surgical complications. An ideal injectable bone repair material generally has the following conditions: good biocompatibility, good osteoconductivity and osteoinductivity, a certain pore structure, and degradability in tissues, etc.

[0004] Biodegradable polyesters such as polylactic acid (PLA), polyglycolic acid (PGA) and their copolymers (polylactic acid-glycolic acid copolymer, PLGA) have gradually become a research hotspot in the orthopedic field due to their good biocompatibility, simple processability and controllable degradability. Especially as bone repair materials, they have been widely developed and studied in recent years. After being implanted into the body, they can degrade in situ to form pores, promote the growth of cells and tissues, and enhance bone integration. However, compared with bone tissue, the strength of degradable polyester materials is lower, and the compressive strength is insufficient, which limits their clinical application in the field of bone repair. In addition, polyester materials have poor hydrophilicity, weak cell adsorption force, and are prone to cause aseptic inflammation. Among them, clinical experimental studies have shown that the degradation products of polylactic acid-based materials are acidic, which will cause local pH changes and have the potential hazard of causing inflammatory reactions. Most importantly, these materials are bio-inert materials, lack active functional groups, and have insufficient bioactivity for promoting tissue regeneration, which is not conducive to obtaining satisfactory bone defect regeneration and repair effects.

[0005] A large number of studies have shown that introducing bioceramic components with a chemical composition similar to that of bone mineral, such as hydroxyapatite particles (HAp) and tricalcium phosphate (TCP), into the polyester material matrix can not only partially neutralize the acidic degradation products of polyester through the continuous release of calcium ions and phosphate ions, but also the released ions can effectively promote bone regeneration. Among inorganic materials, hydroxyapatite not only has no immunogenicity, but also has good osteoconductive ability and biological activity, and its crystal structure is similar to that of mineralized bone salt. Hydroxyapatite has a strong affinity for bone morphogenetic proteins and has no toxic side effects. Organic-inorganic direct composite methods are often used in domestic and foreign research to prepare bone repair materials containing nano-hydroxyapatite. For example, mixing nano-hydroxyapatite with collagen or silk fibroin to prepare scaffold materials can solve the problem of insufficient mechanical strength of single materials and endow the materials with cell compatibility. However, nano-sized hydroxyapatite is extremely prone to agglomeration, resulting in uneven distribution of the inorganic phase and seriously affecting the bone repair effect of the materials. At the same time, when hydroxyapatite is compounded with organic polymers, the interfacial compatibility is poor, which easily causes phase separation of the composite material, is not conducive to cell adhesion and proliferation, and limits its application. Therefore, how to improve the dispersibility of HAp in the organic phase, increase the compatibility between the inorganic phase and the organic phase, promote the adhesion and proliferation of stem cells while endowing it with strong tissue adhesion, and enhance the angiogenesis and osteogenesis of stem cells remains one of the difficult problems that need to be solved urgently in this field.

[0006] Fibrin glue is a commercially available injectable bone repair material that forms a clot through the reaction of thrombin and fibrinogen for tissue sealing and filling damaged tissues. Its components such as fibrinogen and thrombin can be derived from blood or prepared by recombinant technology. Fibrin glue mimics the final stage of blood coagulation. Under the combined action of thrombin and calcium ions, fibrinogen molecules are cleaved into fibrinopeptides A and B to form fibrin monomer proteins. At the same time, under the action of thrombin-activated factor X, fibrin cross-links to form a stable gel. Moreover, fibrin glue, as a natural product, has been proven to have good biocompatibility and safety through clinical practice, has no tissue toxicity, and can be absorbed by tissues.

[0007] In summary, developing an injectable composition that can improve the dispersibility of nano-hydroxyapatite, has biological activity and osteoconductive properties, is degradable, can be absorbed by tissues, is easy to operate, and can adapt to the complex and changeable bone defect environment in the body is expected to be used in the repair of articular cartilage, subchondral bone, jawbone, skull defects, and medical aesthetic filling, etc., and has extremely high application prospects and market value. Summary of the Invention

[0008] The present invention aims at the application fields such as the repair and reconstruction of craniofacial bone defects, articular cartilage defects, and full-thickness subchondral bone defects, as well as facial filling in medical aesthetics, promotes cell adhesion and proliferation, enhances angiogenesis and osteogenesis, prevents chronic inflammatory reactions or infections, and provides a new method for medical repair treatment.

[0009] One of the objectives of the present invention is to provide an injectable bone repair composition, comprising: a mixture and / or reaction product of powder A, powder B, curing liquid A, and curing liquid B, wherein the powder A is a modified nano-hydroxyapatite / degradable polyester composite microsphere with a core-shell structure, the powder B is sulfonated chitosan, the curing liquid A is a fibrinogen solution, and the curing liquid B is a thrombin solution.

[0010] According to the present invention, in the injectable bone repair composition:

[0011] The weight ratio of fibrinogen, powder A, and powder B in the curing liquid A is 1:(5 - 120):(2 - 25), preferably 1:(10 - 25):(2 - 6);

[0012] The volume ratio of the curing liquid A to the curing liquid B is (1 - 10):1, preferably (1 - 5):1.

[0013] According to the present invention, in the injectable bone repair composition:

[0014] The particle size of the composite microspheres of the powder A is 10 - 1000 μm, preferably 15 - 500 μm;

[0015] In the composite microspheres of the powder A, the shell layer is modified nano-hydroxyapatite, and the core layer is a degradable polyester;

[0016] In the composite microspheres of the powder A, the shell layer thickness is 60 - 1000 nm, preferably 70 - 150 nm;

[0017] Calculated based on the total weight of the powder A being 100 wt%, in the powder A, the content of the modified nano-hydroxyapatite is 1 - 30 wt%, preferably 5 - 20 wt%;

[0018] The modified nano-hydroxyapatite is obtained by chemically grafting nano-hydroxyapatite with a modifier, and the modifier is at least one of acrylate compounds, acrylamide compounds, butenamide compounds, and silane coupling agents; preferably, the modifier is selected from at least one of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, aminoacrylate, acrylamide, hydroxyacrylamide, fumaramide, maleic diamide, 3-(trimethoxysilyl)propyl acrylate, 3-(methacryloyloxy)propyltrimethoxysilane, (acryloxymethyl)dimethylmethoxysilane, and vinyltrimethoxysilane; the molar ratio of the modifier to nano-hydroxyapatite is (0.1-100):1, preferably (1-20):1; the particle size of the nano-hydroxyapatite is 10-900 nm, preferably 50-300 nm;

[0019] The biodegradable polyester is selected from at least one of polylactic acid (such as L-polylactic acid, D-polylactic acid, racemic polylactic acid, meso-polylactic acid, etc.), polyglycolic acid, poly(lactic-co-glycolic acid), polycaprolactone, poly(lactic acid-block-polyethylene glycol), polyhydroxyalkanoate, and polyurethane;

[0020] The sulfonated chitosan is obtained by modifying chitosan with a sulfonating agent. Preferably, the sulfonating agent is selected from at least one of sulfur trioxide pyridine, sulfuric acid, chlorosulfonic acid, sulfamic acid, sulfite, sulfonyl chloride, sulfonic anhydride, and sulfimide; the mass ratio of the sulfonating agent to chitosan is (0.1-100):1, preferably (3-20):1;

[0021] In the solidifying solution A, the solvent S1 for dissolving fibrinogen is selected from at least one of normal saline, phosphate buffer solution, ultrapure water, and distilled water; the concentration of fibrinogen in the solidifying solution A is 20-200 mg / mL;

[0022] The thrombin solution is a thrombin solution formed by dissolving thrombin with a calcium chloride solution; preferably, the concentration of the calcium chloride solution is 0.01-0.1 mol / mL; the concentration of thrombin in the thrombin solution (or solidifying solution B) is 20-500 U / mL.

[0023] The modified nano-hydroxyapatite used in the present invention can improve the dispersibility of the nano-hydroxyapatite in the composition, increase the integration of the hydroxyapatite with the organic phase, and graft double-bonded groups onto the surface of the hydroxyapatite. Among the components of the injectable bone repair composition, curing liquid A and curing liquid B are mixed to form a fibrin glue in situ. Curing liquid A containing powders A and B is mixed to form an in situ fibrin glue containing composite microspheres and sulfonated chitosan. The composite microsphere material can be fixed within the gel, and the gel can maintain its intact shape for a long time, thereby allowing it to act in a targeted manner at the bone defect.

[0024] A second object of the present invention is to provide a method for preparing the above-mentioned injectable bone repair composition, comprising: adding modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure and sulfonated chitosan to a fibrinogen solution, mixing them thoroughly, and then adding a thrombin solution, wherein thrombin and fibrinogen interact to form a gel in situ to obtain the injectable bone repair composition.

[0025] According to the present invention, the preparation method of the injectable bone repair composition specifically comprises the following steps:

[0026] Step 1, dissolving fibrinogen in solvent S1 to obtain a fibrinogen solution;

[0027] Step 2: Add modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure and sulfonated chitosan to the fibrinogen solution, mix well at low temperature, and then stand for defoaming to obtain a mixed solution C1, and then add the obtained mixed solution to syringe 1;

[0028] Step 3: dissolving thrombin in a calcium chloride solution to obtain thrombin solution C2, and adding the solution into syringe 2;

[0029] Step 4: Mix the solutions in syringe 1 and syringe 2 by injection, and the resulting material is the injectable bone repair composition.

[0030] According to the present invention, in the method for preparing the injectable bone repair composition:

[0031] The low temperature mixing condition in step 2 is 0-25°C, preferably 4-15°C;

[0032] During the injection mixing in step 4, the volume ratio of the mixed solution C1 in the syringe 1 to the thrombin solution C2 in the syringe 2 is (1-10):1, preferably (1-5):1.

[0033] According to the present invention, the modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure are prepared by a picking emulsion method and a photoinitiation method, specifically by the following preparation method:

[0034] (a) dissolving a degradable polyester in an organic solvent S2 to obtain a degradable polyester solution;

[0035] (b) adding the modified nano-hydroxyapatite to water under ice bath conditions and fully dispersing the water to obtain a suspension, then adding the degradable polyester solution to the modified nano-hydroxyapatite suspension, stirring to form a microsphere phase, and raising the temperature to volatilize the organic solvent to obtain a mixed solution;

[0036] (c) adding a photoinitiator to the mixed solution obtained in step (b) and subjecting the mixture to light treatment to obtain modified nano-hydroxyapatite / degradable polyester composite microspheres having a core-shell structure.

[0037] According to the present invention, in the method for preparing the modified nano-hydroxyapatite / degradable polyester composite microspheres having a core-shell structure:

[0038] The organic solvent S2 in step (a) is selected from at least one of dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, hexafluoroisopropanol, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and 1,4-dioxane, preferably at least one of dichloromethane, chloroform, ethyl acetate, and tetrahydrofuran;

[0039] In the degradable polyester solution obtained in step (a), the concentration of the degradable polyester is 2 to 15 wt %, preferably 5 to 10 wt %;

[0040] The water in step (b) is preferably deionized water;

[0041] In the step (b), the mass ratio of the modified nano-hydroxyapatite to water is (0.001-0.1):1, preferably (0.005-0.01):1;

[0042] The temperature for volatilizing the organic solvent in step (b) can be a common solvent volatilization temperature, for example, 20 to 60° C., preferably 25 to 50° C.;

[0043] The photoinitiator is selected from at least one of an ultraviolet light initiator and a blue light initiator, and any one or more commonly used photoinitiators can be used, such as at least one of Irgacure 819, Irgacure 2959, and Darocur 1173. The amount of the photoinitiator is not particularly limited and can be added in a commonly used amount. For example, the amount of the photoinitiator is 0.1% to 10% of the degradable polyester material.

[0044] The conditions for the light treatment in step (c) are as follows: the light wavelength is 200-500 nm, and the irradiation time is 10-180 min; preferably, the conditions for the light treatment are: the light wavelength is 240-410 nm, and the irradiation time is 30-90 min;

[0045] Step (c) further includes the steps of washing the composite microspheres and freeze-drying. Among them, common operation methods can be used for washing and freeze-drying. For example, deionized water can be used for washing, and then freeze-drying after filtration.

[0046] According to the present invention, the modified nano-hydroxyapatite can be obtained by a surface chemical grafting modification method, using at least one of acrylate compounds, acrylamide compounds, butenamide compounds, and silane coupling agents as a modifier to modify nano-hydroxyapatite.

[0047] According to a specific embodiment of the present invention, a modification method of nano-hydroxyapatite can be synthesized by the method described in the reference document Y Yang, Q Zhang, T Xu, et al. Photocrosslinkable nanocomposite ink for printing strong, biodegradable and bioactive bone graft [J]. Biomaterials 263 (2020) 120378. For example, the following steps can be adopted: under normal temperature and in an atmosphere of a protective gas (such as nitrogen), disperse the dried nano-hydroxyapatite in dimethylformamide, add polyhexamethylene diisocyanate and dibutyltin dilaurate, mix well and react, then add 2-hydroxyethyl methacrylate to the mixed solution and continue the reaction; then add methanol to terminate the reaction to obtain a suspension of 2-hydroxyethyl methacrylate-grafted nano-hydroxyapatite; finally, centrifuge the suspension, wash it with ultra-dry dichloromethane, and dry it in a vacuum drying oven to obtain 2-hydroxyethyl methacrylate-grafted nano-hydroxyapatite powder.

[0048] According to a specific embodiment of the present invention, another method for nano-hydroxyapatite can be as follows: add 3-(methacryloyloxy)propyltrimethoxysilane to an ethanol / water mixed solution and hydrolyze it; add nano-hydroxyapatite particles to the ethanol / water mixed solution to form a dispersion; gradually add the hydrolyzed 3-(methacryloyloxy)propyltrimethoxysilane solution dropwise to the nano-hydroxyapatite dispersion system and heat to react; after the reaction is completed, centrifuge the reaction mixture; wash the collected nano-hydroxyapatite particles with water and ethanol respectively, and vacuum-dry the washed nano-hydroxyapatite particles to obtain modified nano-hydroxyapatite.

[0049] According to the present invention, the sulfonated chitosan can be obtained by modifying chitosan through the sulfonation reaction commonly used in the prior art. For example, chitosan can be modified with sulfur trioxide - pyridine under alkaline conditions, or modified with sulfuric acid or chlorosulfonic acid. According to a specific embodiment of the present invention, one modification method of sulfonated chitosan is as follows: Dissolve chitosan and an alkaline compound (such as sodium carbonate) in distilled water to form a mixed solution, then add sulfur trioxide - pyridine thereto, heat the reaction, dialyze, and freeze - dry to obtain sulfonated chitosan. According to another specific embodiment of the present invention, another modification method of sulfonated chitosan is as follows: Add chitosan to formamide, then add concentrated sulfuric acid and chlorosulfonic acid thereto, filter by suction, dialyze, and freeze - dry after the reaction to obtain sulfonated chitosan.

[0050] The third object of the present invention is to provide an application of an injectable repair composition in implantable and interventional medical materials for in - situ repair and treatment of bone injuries and defects. The injectable bone repair composition is the injectable bone repair composition described in the first object of the present invention or the injectable bone repair composition obtained by the preparation method described in the second object of the present invention.

[0051] According to the present invention, the application includes: using a dual - syringe or Y - type syringe. In one syringe, a fibrinogen solution C1 containing modified nano - hydroxyapatite / degradable polyester composite microspheres with a core - shell structure and sulfonated chitosan is filled, and in the other syringe, a thrombin solution C2 is filled. At the same time, the solutions in the two syringes are uniformly injected into the defect site, and a gel is quickly formed at the defect site to fill and repair the defect site. In the two syringes, the volume ratio of the fibrinogen solution C1 to the thrombin solution C2 is (1 - 10):1, preferably (1 - 5):1. During the injection of the dual - syringe / Y - type syringe into the bone defect site, filling and repair are carried out according to the shape of the defect site, so that the shape of the gel fits the edge of the defect notch, which is suitable for repairing injuries of various shapes and areas.

[0052] The advantages of the present invention are as follows:

[0053] 1. The polymer material and the inorganic material form a multiple hybrid network structure, and hydroxyapatite is uniformly distributed therein, realizing a high degree of integration of the organic - inorganic phase; it can realize the assembly of inorganic solid particles and organic polymer phases to prepare organic / inorganic composite shell materials with special structures or properties.

[0054] 2. The injectable bone repair composition can adhere firmly and form in the defect site. Utilizing the biological activity of sulfonated chitosan, it can induce cell osteogenic and angiogenic differentiation under the condition of no exogenous growth factors, reducing the potential uncontrollable clinical risks of exogenous growth factors and having broad application prospects in the field of bone defect regeneration and repair. At the same time, sulfonated chitosan can also provide a certain antibacterial effect, effectively avoiding bacterial infection during the bone defect repair process.

[0055] 3. Using fibrinogen solution and thrombin solution loaded with active ingredients to in-situ form fibrin glue at the bone defect site, it has a fast curing and forming speed, adapts to the shape of the defect site, and closely and seamlessly combines with the defect site to achieve complete repair. It is convenient for nutrient components to penetrate, and can also play a role in cell recruitment, providing a good growth space for cells and promoting cell proliferation. During the surgical operation, the operation is simple, and the doctor can freely shape in the debridement space. It is especially suitable for clinical doctors to perform regeneration and repair after debriding the bone defect site.

[0056] 4. Fibrin and nano-hydroxyapatite delay the degradation rate of the polyester material, enabling it to have sufficient mechanical strength in the early stage after injection to meet the initial load-bearing needs. As tissue regenerates, the polyester component degrades to form pores in-situ in the body, and the polyester material gradually degrades and is absorbed by the body, making way for the regenerated tissue.

[0057] 5. In practical applications, according to the bone defect location, bone defect degree, and regeneration rate, adjusting the ratio of each component can obtain a bone repair material with appropriate mechanical properties and a degradation rate matching the new bone formation rate. Selecting an appropriate solid phase ratio in the injection combination can achieve the best bone defect repair effect. By adjusting the ratio of the material components, the pore formation rate of the material can be precisely controlled to achieve a match between the degradation rate and the tissue ingrowth and new bone formation rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a schematic diagram for the preparation of modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure in Examples 1-2 of the present invention.

[0059] Figure 2 is the electron microscope photograph of composite microspheres with different sizes, Figure 2a which is the electron microscope photograph of the modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure obtained in Example 1, Figure 2b and which is the electron microscope photograph of the modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure obtained in Example 2.

[0060] Figure 3 It is a picture of the injectable composition obtained by mixing fibrinogen solution C1 and thrombin solution C2 containing modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure and sulfonated chitosan.

[0061] Figure 4 Pictures of the repair of cartilage defects by the bone repair compositions obtained in Examples 1-2 and Comparative Examples 1-2.

[0062] Figure 5 Experimental results of tissue sectioning and staining of articular cartilage after 12 weeks of repair of articular cartilage with the bone repair compositions obtained in Examples 1-2 and Comparative Examples 1-2. Detailed implementation manners

[0063] The present invention will be specifically described below in conjunction with specific embodiments. It is necessary to point out here that the following embodiments are only for further illustration of the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0064] The raw materials used in the examples and comparative examples, if not specifically limited, are all disclosed in the prior art. For example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0065] Example 1

[0066] The modified nano-hydroxyapatite described in Example 1 of the present invention was synthesized according to the method described in the reference (YYang, Q Zhang, T Xu, et al. Photocrosslinkable nanocomposite ink for printing strong, biodegradable and bioactive bone graft [J]. Biomaterials 263 (2020) 120378), and the entire content of this reference is taken as one of the specific implementation manners of the present invention.

[0067] 1) Preparation of modified nano-hydroxyapatite

[0068] 10 g of nano-hydroxyapatite (60 - 80 nm, Macklin) was placed in a vacuum drying oven and dried at 120 °C for 48 h. Under normal temperature and nitrogen atmosphere, the dried nano-hydroxyapatite was dispersed in 200 mL of dimethylformamide. At 55 °C, 2 mL (12.5 mmol) of polyhexamethylene diisocyanate and 0.2 mL (0.3 mmol) of dibutyltin dilaurate were added, and the mixture was thoroughly mixed and reacted for 24 h. Subsequently, 4 mL (66 mmol) of 2-hydroxyethyl methacrylate was added to the mixture, and the reaction was carried out at 55 °C for 5 h. 200 mL of methanol was added to terminate the reaction, and a suspension of 2-hydroxyethyl methacrylate grafted nano-hydroxyapatite was obtained. Finally, the suspension was centrifuged, washed with ultra-dry dichloromethane, and dried in a vacuum drying oven at 50 °C for 72 h to obtain 2-hydroxyethyl methacrylate grafted nano-hydroxyapatite powder P1.

[0069] 2) Preparation of modified nano-hydroxyapatite / degradable polyester composite microspheres

[0070] 10 g of polylactic acid (PLA 4032D, NatureWorks, USA) pellets were dissolved in 90 g of dichloromethane to form a solution with a polylactic acid concentration of 10%. Under ice bath conditions, 1.5 g of modified nano-hydroxyapatite P1 was added to 300 mL of deionized water and ultrasonically dispersed thoroughly to form a suspension. Using the Picking emulsion method, the dichloromethane solution of polylactic acid was added to the suspension of modified nano-hydroxyapatite, and the mass ratio of the two was 1:3. The mixture was stirred at a speed of 500 r / min for 30 min to form a microsphere phase. The temperature was raised to 50 °C, the speed was reduced to 150 r / min, and the mixture was stirred for 6 h to allow the dichloromethane to evaporate fully. Subsequently, 3 mg of photoinitiator I819 was added to the solution and stirred thoroughly. The mixture was exposed to ultraviolet light with a wavelength of 365 nm and an energy of 10 mW / cm 2 for 1 h to in-situ polymerize and coat the 2-hydroxyethyl methacrylate grafted hydroxyapatite on the outer layer of the polylactic acid microspheres to form a core-shell structure. The obtained material was washed with deionized water, filtered, and freeze-dried for 24 h to obtain modified nano-hydroxyapatite / degradable polyester composite microspheres A1.

[0071] 3) Preparation of sulfonated chitosan

[0072] Disperse 2 g of chitosan (Sigma - aldrich, CAS: 9012 - 76 - 4) in 150 mL of deionized water, add 4 g of sodium carbonate, and adjust the pH of the solution to be greater than 9. Add 6 g of sulfur trioxide pyridine to the solution, and maintain the mixture at 60 °C under argon for 24 h to form a yellow liquid. Use the method of washing with ethanol and suction filtration to filter the obtained yellow solution to obtain a solid material. After washing the solid material with ethanol 3 - 4 times, add it to deionized water. Adopt the method of dialysis to remove unreacted chemical reagents or small molecules. Freeze - dry the dialyzed material for 24 h to obtain sulfonated chitosan powder B1.

[0073] 4) Preparation of injectable bone repair composition

[0074] Dissolve fibrinogen (Macklin, CAS: 9001 - 32 - 5) in physiological saline with a concentration of 0.9% to prepare 6 mL of fibrinogen solution with a concentration of 80 mg / mL. Add 12 g of modified nano - hydroxyapatite / degradable polyester composite microspheres A1 and 2.5 g of sulfonated chitosan B1 to the solution. After mixing well at 10 °C and standing to defoam, then add the mixed solution to syringe 1. Dissolve thrombin (Innochem, CAS: 9002 - 04 - 4) in calcium chloride solution with a concentration of 0.1 mol / mL to prepare 3 mL of thrombin solution with a concentration of 300 U / mL, and add it to another syringe 2. Inject and mix the solutions in the two syringes in equal volumes, and the obtained material is the bone repair composition.

[0075] Example 2

[0076] 1) Preparation of modified nano - hydroxyapatite

[0077] Add 75 mmol of 3 - (methacryloyloxy) propyltrimethoxysilane to 30 mL of 80% ethanol aqueous solution, and hydrolyze it at 20 °C for 6 h. Add 10 g of nano - hydroxyapatite particles (60 - 80 nm, Macklin) to 80 mL of 90% ethanol aqueous solution to form a dispersion. Dropwise add the hydrolyzed 3 - (methacryloyloxy) propyltrimethoxysilane solution into the nano - hydroxyapatite dispersion system, and react at 55 °C for 24 h. After the reaction, centrifuge the reaction mixture. Wash the collected modified nano - hydroxyapatite particles with water and ethanol respectively. Vacuum - dry the washed modified nano - hydroxyapatite particles at 60 °C for 10 h to obtain modified nano - hydroxyapatite P2.

[0078] 2) Preparation of composite microspheres of modified nano - hydroxyapatite and degradable polyester

[0079] 10g of polylactic acid (PLA 4032D, NatureWorks, USA) pellets were dissolved in 90g of dichloromethane to prepare a 10% polylactic acid solution. 1.5g of modified nanohydroxyapatite P2 was added to 300mL of deionized water in an ice bath and thoroughly ultrasonically dispersed to form a suspension. Using the Picking emulsion method, the polylactic acid solution in dichloromethane was added to the modified nanohydroxyapatite suspension at a mass ratio of 1:3. The mixture was stirred at 800 rpm for 30 minutes to form microspheres. The temperature was raised to 50°C, the speed was reduced to 150 rpm, and the mixture was stirred for 6 hours to allow the dichloromethane to evaporate. Subsequently, 6mg of photoinitiator I819 was added to the solution and thoroughly stirred. The mixture was exposed to 365nm UV light for 1 hour, causing the modified hydroxyapatite P2 to polymerize in situ and coat the outer layer of the polylactic acid microspheres, forming a core-shell structure. The obtained material was washed with deionized water, filtered, and freeze-dried for 24 hours to obtain composite microspheres A2.

[0080] 3) Preparation of sulfonated chitosan

[0081] At room temperature, add 2g of chitosan (Sigma-aldrich, CAS: 9012-76-4) to 50mL of formamide solution, mix evenly, and let it stand to defoam. Add 5mL of 98% concentrated sulfuric acid to the solution and mix evenly. Under argon protection, add 10mL of chlorosulfonic acid dropwise to the mixture and mix evenly. Place the mixture at 2°C to react for 3h to obtain a transparent yellow solution. Use ethanol washing and filtration to filter the obtained yellow solution to obtain a solid material. After washing the solid material with ethanol 3-4 times, add it to deionized water. Use dialysis to remove unreacted chemical reagents or small molecules. Freeze-dry the dialyzed material for 24h to obtain sulfonated chitosan powder B2.

[0082] 4) Preparation of injectable composition

[0083] Dissolve fibrinogen (Macklin, CAS: 9001-32-5) in 0.9% saline to prepare 6 mL of a 200 mg / mL fibrinogen solution. Add 12 g of composite microspheres A2 and 2.5 g of sulfonated chitosan B2 to the fibrinogen solution, mix thoroughly at 10°C, and allow to stand to defoam. The mixture is then added to syringe 1. Dissolve thrombin (Innochem, CAS: 9002-04-4) in 0.1 mol / mL calcium chloride solution to prepare 3 mL of a 200 U / mL thrombin solution, which is then added to another syringe 2. The solutions in the two syringes are mixed by injection at a 1:3 volume ratio to create the bone repair composition.

[0084] Example 3

[0085] 1) Preparation of modified nano-hydroxyapatite

[0086] 10 g of nano-hydroxyapatite (60 - 80 nm, Macklin) was placed in a vacuum drying oven and dried at 120 °C for 48 h. Under normal temperature and nitrogen atmosphere, the dried nano-hydroxyapatite was dispersed in 200 mL of dimethylformamide. At 55 °C, 2 mL (12.5 mmol) of polyhexamethylene diisocyanate and 0.2 mL (0.3 mmol) of dibutyltin dilaurate were added, mixed well, and reacted for 24 h. Subsequently, 4 mL (66 mmol) of 2-hydroxyethyl methacrylate was added to the mixture and reacted at 55 °C for 5 h. 200 mL of methanol was added to terminate the reaction, and a suspension of 2-hydroxyethyl methacrylate grafted nano-hydroxyapatite was obtained. Finally, the suspension was centrifuged, washed with ultra-dry dichloromethane, and dried in a vacuum drying oven at 50 °C for 72 h to obtain 2-hydroxyethyl methacrylate grafted nano-hydroxyapatite powder P3.

[0087] 2) Preparation of modified nano-hydroxyapatite / degradable polyester composite microspheres

[0088] 10 g of poly (lactic-co-glycolic acid) (PLGA, Esunmed, CAS: 26780 - 50 - 7) was dissolved in 90 g of dichloromethane to form a solution with a poly (lactic acid) concentration of 10%. Under ice bath conditions, 1.5 g of modified nano-hydroxyapatite P3 was added to 300 mL of deionized water and ultrasonically dispersed to form a suspension. Using the Picking emulsion method, the dichloromethane solution of poly (lactic acid) was added to the suspension of modified nano-hydroxyapatite, and the mass ratio of the two was 1:3. Stir at a speed of 600 r / min for 30 min to form a microsphere phase. Raise the temperature to 50 °C, reduce the speed to 150 r / min, and stir for 6 h to allow the dichloromethane to evaporate fully. Subsequently, 3 mg of photoinitiator I819 was added to the solution and stirred well. The mixture was exposed to ultraviolet light with a wavelength of 365 nm and an energy of 10 mW / cm 2 for 1 h to in-situ polymerize and coat the 2-hydroxyethyl methacrylate grafted hydroxyapatite on the outer layer of the poly (lactic acid) microspheres to form a core-shell structure. The obtained material was washed with deionized water, filtered, and freeze-dried for 24 h to obtain modified nano-hydroxyapatite / degradable polyester composite microspheres A3.

[0089] 3) Preparation of sulfonated chitosan

[0090] Disperse 2 g of chitosan (Sigma - aldrich, CAS: 9012 - 76 - 4) in 150 mL of deionized water, add 4 g of sodium carbonate, and adjust the pH of the solution to be greater than 9. Add 6 g of sulfur trioxide pyridine to the solution, and maintain the mixture at 60 °C under argon for 24 h to form a yellow liquid. Use the method of washing with ethanol and suction filtration to filter the obtained yellow solution to obtain a solid material. After washing the solid material with ethanol 3 - 4 times, add it to deionized water. Use the method of dialysis to remove unreacted chemical reagents or small molecules. Freeze - dry the dialyzed material for 24 h to obtain sulfonated chitosan powder B3.

[0091] 4) Preparation of injectable bone repair composition

[0092] Dissolve fibrinogen (Macklin, CAS: 9001 - 32 - 5) in physiological saline with a concentration of 0.9% to prepare a fibrinogen solution with a concentration of 80 mg / mL, 6 mL. Add 12 g of composite microsphere A3 and 2.5 g of sulfonated chitosan B3 to the solution. After mixing evenly at 10 °C and standing to defoam, then add the mixed solution to syringe 1. Dissolve thrombin (Innochem, CAS: 9002 - 04 - 4) in calcium chloride solution with a concentration of 0.1 mol / mL to prepare a thrombin solution with a concentration of 300 U / mL, 3 mL, and add it to another syringe 2. Inject and mix the solutions in the two syringes in equal volumes, and the obtained material is the bone repair composition.

[0093] Example 4

[0094] 1) Preparation of modified nano - hydroxyapatite

[0095] Place 10 g of nano - hydroxyapatite (60 - 80 nm, Macklin) in a vacuum drying oven and dry it at 120 °C for 48 h. Under normal temperature and nitrogen atmosphere, disperse the dried nano - hydroxyapatite in 200 mL of dimethylformamide. Add 2 mL (12.5 mmol) of polyhexamethylene diisocyanate and 0.2 mL (0.3 mmol) of dibutyltin dilaurate at 55 °C, mix well, and continue the reaction for 24 h. Subsequently, add 4 mL (66 mmol) of 2 - hydroxyethyl methacrylate to the mixture and react at 55 °C for 5 h. Add 200 mL of methanol to terminate the reaction to obtain a suspension of 2 - hydroxyethyl methacrylate - grafted nano - hydroxyapatite. Finally, centrifuge the suspension, wash it with ultra - dry dichloromethane, and dry it in a vacuum drying oven at 50 °C for 72 h to obtain 2 - hydroxyethyl methacrylate - grafted nano - hydroxyapatite powder P4.

[0096] 2) Preparation of modified nano - hydroxyapatite / biodegradable polyester composite microspheres

[0097] 10g of polycaprolactone (PCL, Sigma-aldrich, CAS: 24980-41-4) was dissolved in 90g of dichloromethane to prepare a solution with a polylactic acid concentration of 10%. 1.5g of modified nanohydroxyapatite P4 was added to 300mL of deionized water under ice bath conditions and fully ultrasonically dispersed to form a suspension. Using the Picking emulsion method, the dichloromethane solution of polylactic acid was added to the suspension of modified nanohydroxyapatite with a mass ratio of 1:3. Stir at a speed of 500r / min for 30min to form a microsphere phase. Raise the temperature to 50°C, reduce the speed to 150r / min, and stir for 6h to allow the dichloromethane to fully evaporate. Subsequently, 3mg of photoinitiator I819 was added to the solution and stirred thoroughly. The mixture was exposed to 365nm and an energy of 10mW / cm 2 The microspheres were then exposed to ultraviolet light for 1 hour, allowing the hydroxyethyl methacrylate-grafted hydroxyapatite to polymerize in situ and coat the outer layer of the polylactic acid microspheres, forming a core-shell structure. The resulting material was washed with deionized water, filtered, and freeze-dried for 24 hours to obtain modified nanohydroxyapatite / degradable polyester composite microspheres A4.

[0098] 3) Preparation of sulfonated chitosan

[0099] Disperse 2g of chitosan (Sigma-aldrich, CAS: 9012-76-4) in 150mL of deionized water, add 4g of sodium carbonate, and adjust the solution pH to greater than 9. Add 6g of sulfur trioxide pyridine to the solution, and maintain the mixture at 60°C under argon for 24 hours to form a yellow liquid. Use ethanol washing and filtration to filter the resulting yellow solution to obtain a solid material. After washing the solid material with ethanol 3-4 times, add it to deionized water. Use dialysis to remove unreacted chemical reagents or small molecules. Freeze-dry the dialyzed material for 24 hours to obtain sulfonated chitosan powder B4.

[0100] 4) Preparation of injectable bone repair composition

[0101] Dissolve fibrinogen (Macklin, CAS: 9001-32-5) in 0.9% saline to prepare 6 mL of 80 mg / mL fibrinogen solution. Add 12 g of composite microspheres A4 and 2.5 g of sulfonated chitosan B4 to this solution, mix thoroughly at 10°C, and allow to stand to defoam. The mixture is then added to syringe 1. Dissolve thrombin (Innochem, CAS: 9002-04-4) in 0.1 mol / mL calcium chloride solution to prepare 3 mL of 300 U / mL thrombin solution, which is then added to syringe 2. The solutions in the two syringes are mixed by injecting equal volumes. The resulting material is the bone repair composition.

[0102] Example 5

[0103] The modified nano-hydroxyapatite P1, composite microspheres A1, and sulfonated chitosan B1 are the same as those in Example 1.

[0104] Preparation of injectable bone repair composition:

[0105] Dissolve fibrinogen (Macklin, CAS: 9001-32-5) in physiological saline with a concentration of 0.9% to prepare 6 mL of fibrinogen solution with a concentration of 80 mg / mL. Add 8 g of composite microspheres A1 and 2.5 g of sulfonated chitosan B1 to the fibrinogen solution. After fully mixing evenly at 10°C and standing to defoam, then add the mixture into syringe 1. Dissolve thrombin (Innochem, CAS: 9002-04-4) with a 0.1 mol / mL calcium chloride solution to prepare 3 mL of thrombin solution with a concentration of 300 U / mL, and add it into another syringe 2. Inject and mix the solutions in the two syringes in equal volumes, and the obtained material is the bone repair composition.

[0106] Example 6

[0107] The modified nano-hydroxyapatite P1, composite microspheres A1, and sulfonated chitosan B1 are the same as those in Example 1.

[0108] Preparation of injectable bone repair composition:

[0109] Dissolve fibrinogen (Macklin, CAS: 9001-32-5) in physiological saline with a concentration of 0.9% to prepare 6 mL of fibrinogen solution with a concentration of 80 mg / mL. Add 6 g of composite microspheres A1 and 2.5 g of sulfonated chitosan B1 to the fibrinogen solution. After fully mixing evenly at 10°C and standing to defoam, then add the mixture into syringe 1. Dissolve thrombin (Innochem, CAS: 9002-04-4) with a 0.1 mol / mL calcium chloride solution to prepare 3 mL of thrombin solution with a concentration of 300 U / mL, and add it into another syringe 2. Inject and mix the solutions in the two syringes in equal volumes, and the obtained material is the bone repair composition.

[0110] Comparative Example 1

[0111] 1) Preparation of nano-hydroxyapatite and biodegradable polyester microsphere composite

[0112] 10g of polylactic acid pellets (PLA 4032D, NatureWorks, USA) were dissolved in 90g of dichloromethane to prepare a solution with a polylactic acid concentration of 10%. 1.5g of nanohydroxyapatite (60-80nm, Macklin) was added to 300mL of deionized water under ice bath conditions and thoroughly ultrasonically dispersed to form a suspension. Using the Picking emulsion method, the dichloromethane solution of polylactic acid was added to the suspension of nanohydroxyapatite in a mass ratio of 1:3. The mixture was stirred at a speed of 500r / min for 30min to form a microsphere phase. The temperature was raised to 50°C, the speed was reduced to 150r / min, and the mixture was stirred for 6h to allow the dichloromethane to fully evaporate. The resulting material was washed with deionized water, filtered, and freeze-dried for 24h to obtain composite microspheres A5.

[0113] 2) Preparation of sulfonated chitosan

[0114] Disperse 2g of chitosan (Sigma-aldrich, CAS: 9012-76-4) in 150mL of deionized water, add 4g of sodium carbonate, and adjust the solution pH to greater than 9. Add 6g of sulfur trioxide pyridine to the solution, and maintain the mixture at 60°C under argon for 24 hours to form a yellow liquid. Use ethanol washing and filtration to filter the resulting yellow solution to obtain a solid material. After washing the solid material with ethanol 3-4 times, add it to deionized water. Use dialysis to remove unreacted chemical reagents or small molecules. Freeze-dry the dialyzed material for 24 hours to obtain sulfonated chitosan powder B5.

[0115] 3) Preparation of injectable composition

[0116] Dissolve fibrinogen (Macklin, CAS: 9001-32-5) in 0.9% saline to prepare 6 mL of 80 mg / mL fibrinogen solution. Add 12 g of composite powder A5 and 2.5 g of sulfonated chitosan B5 to the fibrinogen solution, mix thoroughly at 10°C, and allow to stand to defoam. The mixture is then added to syringe 1. Dissolve thrombin (Innochem, CAS: 9002-04-4) in 0.1 mol / mL calcium chloride solution to prepare 3 mL of 300 U / mL thrombin solution, which is then added to syringe 2. The solutions in the two syringes are mixed by injecting equal volumes to obtain the resulting material, which is the bone repair composition.

[0117] Comparative Example 2

[0118] An existing tissue repair commercial medical fibrin glue (ETHICON) was used as comparative example 2.

[0119] Test Example 1

[0120] The particle sizes of the composite microspheres obtained in Examples 1-4 and Comparative Example 1 were measured using an Anton Paar PSA 1190 laser particle size analyzer, and the results are shown in Table 1.

[0121] Table 1 Particle Size and Shell Thickness Test

[0122] Sample Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Particle size (μm) 81 17 58 87 85 Shell thickness (nm) 73 92 84 70 -

[0123] Test Example 2

[0124] In Examples 1-4, according to step (3), fibrinogen solutions and thrombin solutions containing composite microspheres and sulfonated chitosan were respectively prepared, and the prepared solutions were mixed and then solidified into a shape, as Figure 3 shown.

[0125] Test Example 3

[0126] According to the method specified in GB / T 1041-2008 of the national standard, the injectable compositions prepared in Example 1 and Comparative Examples 2-4 were tested for their compressive strength using a mechanical testing machine, and the pressure loading rate was kept constant at 1 mm / s.

[0127] The proportions of the components of the injectable compositions in Example 1 and Comparative Examples 3 and 4 were different, and the content of the composite microspheres decreased in the order of Example 1, Comparative Example 3, and Comparative Example 4. It can be seen that the composite microspheres can enhance the strength of the injectable composition. Compared with Comparative Example 2 (commercial fibrin glue), the strength of the injectable composition has been greatly improved, and it can meet the mechanical strength required for bone repair.

[0128] Table 2 Compressive Strength Test

[0129] Sample Example 1 Comparative Example 2 Example 5 Example ⑥ Compressive strength (kPa) 143 25 112 98

[0130] Test Example 4

[0131] To evaluate the bone injury repair ability of the material, a cylindrical defect was created in the trochlea of the femur of the hind leg of a rat, and the defect repair was evaluated using the material.

[0132] Defect model construction and application of the material: 60 healthy male SD rats with a body weight between 300 and 350 g were used in the experiment. The SD rats were anesthetized with 3% sodium pentobarbital (dosage / body weight = 40 mg / kg). The rats were randomly divided into 4 groups. A cylindrical full-thickness cartilage defect with a diameter of 2 mm and a depth of 1 mm was created at the center of the trochlea of the right hind leg femur of the SD rats using a sterilized biopsy forceps. The defects were repaired with Examples 1-2 and Comparative Examples 1-2 respectively. After the operation, penicillin was injected routinely for 1 week, and the rats were put back into the breeding cage to move freely after waking up from anesthesia.

[0133] Gross observation of defect repair: At 12 weeks after surgery, each group of animals was sacrificed by carbon dioxide asphyxiation, and the joints repairing the defects were taken for observation of swelling, damage, infection and effusion in the joint cavity, the repair condition at the defect edge, the flatness of the cartilage surface, the transparency of the newly formed cartilage of the defect filler, etc.

[0134] It can be seen from Figure 4 that in the control group, the bone defects of the rats untreated at the defect sites were still obvious, and the defect sites were still in a concave state; the bone defects in Comparative Examples 1 and 2 were repaired to a certain extent, the repaired plane was not significantly concave but was not smooth, and the edges were not fully repaired; the cartilage defects in Examples 1 and 2 were basically completely repaired, the repaired surface was basically non-concave and relatively smooth, the edges were basically repaired, and the repaired cartilage was in a semi-transparent state.

[0135] Test Example 5

[0136] Histological evaluation: The cartilage in the repair area was fixed with 4% paraformaldehyde, dehydrated with gradient ethanol (50% - 100%) after rinsing with PBS, transparently treated by replacing with xylene and then embedded in paraffin. It was cut into 5-μm thin slices on a glass slide, and the tissue sections were stained with hematoxylin-eosin (HE), toluidine blue (TB), and immunohistochemical staining of type II collagen.

[0137] Experimental results of histological sectioning and staining of articular cartilage 12 weeks after repair:

[0138] HE staining: The cell density in Comparative Example 1 was low and the tissue was loose; Comparative Example 2 could form cartilage lacuna structures and the number of cells was small; while Examples 1 and 2 had better repair effects on the defects.

[0139] TB staining: Compared with Comparative Examples 1 and 2, the staining colors in Examples 1 and 2 were deeper, indicating that the secretion amount of glycosaminoglycan was more, indicating better repair effects of the bone defects.

[0140] Collagen staining: The staining characteristics of type II collagen in Examples 1 and 2 were the most obvious, indicating that these two materials could form repair tissues with the characteristics of natural cartilage.

[0141] In this article, specific examples are used to elaborate on the principles and implementation modes of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention, including the best mode, and also enables any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the literal expression of the claims, or if they include equivalent structural elements that have no substantial difference from the literal expression of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. An injectable bone repair composition, comprising: A mixture and / or reactant of powder A, powder B, solidifying liquid A and solidifying liquid B, wherein the powder A is a modified nano-hydroxyapatite / polyester composite microsphere with a core-shell structure, the powder B is sulfonated chitosan, the solidifying liquid A is a fibrinogen solution, and the solidifying liquid B is a thrombin solution.

2. The injectable bone repair composition according to claim 1, wherein the weight ratio of fibrinogen, powder A, and powder B in the solidifying liquid A is 1:(5-120):(2-25), preferably 1:(10-25):(2-6); and / or, the concentration of fibrinogen in the solidifying liquid A is 20-200 mg / mL; and / or, the concentration of thrombin in the solidifying liquid B is 20-500 U / mL; and / or, the volume ratio of the solidifying liquid A to the solidifying liquid B is (1-10):1, preferably (1-5):

1.

3. The injectable bone repair composition according to claim 1, wherein for the powder A, the particle size of the composite microsphere is 10-1000 μm, preferably 15-500 μm; and / or, in the composite microsphere of the powder A, the shell layer is modified nano-hydroxyapatite and the core layer is a biodegradable polyester; and / or, in the composite microsphere of the powder A, the shell layer thickness is 60-1000 nm, preferably 70-150 nm; and / or, calculated based on the total weight of the powder A being 100 wt%, in the powder A, the content of the modified nano-hydroxyapatite is 1-30 wt%, preferably 5-20 wt%; and / or, the modified nano-hydroxyapatite is obtained by chemically grafting nano-hydroxyapatite with a modifier, and the modifier is at least one of acrylate compounds, acrylamide compounds, butenamide compounds, and silane coupling agents; preferably, the modifier is selected from at least one of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, aminoacrylate, acrylamide, hydroxyacrylamide, fumaramide, maleic diamide, 3-(trimethoxysilyl)propyl acrylate, 3-(methacryloyloxy)propyltrimethoxysilane, (acryloxymethyl)dimethylmethoxysilane, and vinyltrimethoxysilane; and / or, the molar ratio of the modifier to nano-hydroxyapatite is (0.1-100):1, preferably (1-20):1; and / or, the particle size of the nano-hydroxyapatite is 10-900 nm, preferably 50-300 nm; and / or, the biodegradable polyester is selected from at least one of polylactic acid, polyglycolic acid, poly(lactic-co-glycolic acid), polycaprolactone, poly(lactic acid-polyethylene glycol) block copolymer, polyhydroxyalkanoate, and polyurethane; and / or, The sulfonated chitosan is obtained by modifying chitosan with a sulfonating agent. Preferably, the sulfonating agent is selected from at least one of pyridine sulfur trioxide, sulfuric acid, chlorosulfonic acid, sulfamic acid, sulfite, sulfonyl chloride, sulfonic anhydride, and sulfimide; and / or, the mass ratio of the sulfonating agent to chitosan is (0.1 to 100):1, preferably (3 to 20):1; and / or, In the curing liquid A, the solvent S1 for dissolving fibrinogen is selected from at least one of normal saline, phosphate buffer solution, ultrapure water, and distilled water; and / or, The thrombin solution is a thrombin solution formed by dissolving thrombin in a calcium chloride solution; preferably, the concentration of the calcium chloride solution is 0.01 to 0.1 mol / mL.

4. A method for preparing the injectable bone repair composition according to any one of claims 1 to 3, comprising: Adding the modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure and sulfonated chitosan to the fibrinogen solution, fully mixing evenly, and then adding the thrombin solution to in-situ form a gel to obtain the injectable bone repair composition.

5. The preparation method according to claim 4, characterized in that, The preparation method of the injectable bone repair composition specifically includes the following steps: Step 1: Dissolve fibrinogen in the solvent S1 to obtain a fibrinogen solution; Step 2: Add the modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure and sulfonated chitosan to the fibrinogen solution, mix evenly at low temperature, and then stand to defoam to obtain a mixed liquid C1. Subsequently, add the obtained mixed liquid C1 into syringe 1; Step 3: Dissolve thrombin in the calcium chloride solution to obtain a thrombin solution C2, and add it into syringe 2; Step 4: Inject and mix the solutions in syringe 1 and syringe 2, and the obtained material is the injectable bone repair composition.

6. According to the preparation method described in claim 5, wherein, The condition of mixing at low temperature in step 2 is 0 to 25 °C, preferably 4 to 15 °C; and / or, When injecting and mixing in step 4, the volume ratio of the mixed liquid C1 in syringe 1 to the thrombin solution C2 in syringe 2 is (1 to 10):1, preferably (1 to 5):

1.

7. The preparation method according to claim 4 or 5, characterized in that, The modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure are obtained by the following preparation method: (a) Dissolve the degradable polyester in the organic solvent S2 to obtain a degradable polyester solution; (b) Under ice bath conditions, add the modified nano-hydroxyapatite into water and fully disperse to obtain a suspension, and then add the degradable polyester solution into the suspension of the modified nano-hydroxyapatite, stir to form a microsphere phase, and raise the temperature to volatilize the organic solvent to obtain a mixed liquid; (c) Add a photoinitiator to the mixed liquid obtained in step (b) and perform light treatment to obtain the modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure.

8. According to the preparation method described in claim 7, wherein, The organic solvent S2 in the step (a) is selected from at least one of dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, hexafluoroisopropanol, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, 1,4-dioxane, and is preferably selected from at least one of dichloromethane, chloroform, ethyl acetate, and tetrahydrofuran; and / or, In the biodegradable polyester solution obtained in the step (a), the concentration of the biodegradable polyester is 2 to 15 wt%, preferably 5 to 10 wt%; and / or, In the step (b), the mass ratio of the modified nano-hydroxyapatite to deionized water is (0.001 to 0.1):1, preferably (0.005 to 0.01):1; and / or, In the step (b), the temperature for the evaporation of the organic solvent is 20 to 60 °C, preferably 25 to 50 °C; and / or, The photoinitiator is selected from at least one of ultraviolet photoinitiators and blue light photoinitiators; and / or, The conditions for the light treatment in the step (c) are: light wavelength 200 to 500 nm, irradiation time 10 to 180 min; preferably, the conditions for the light treatment are: light wavelength 240 to 410 nm, irradiation time 30 to 90 min.

9. Use of an injectable repair composition in implantable and interventional medical materials for in-situ repair treatment of bone injuries and defects, wherein the injectable bone repair composition is the injectable bone repair composition according to any one of claims 1 to 3 or the injectable bone repair composition obtained by the preparation method according to any one of claims 4 to 8.

10. The application according to claim 9, characterized in that, The use includes: using a dual-channel syringe or a Y-shaped syringe, wherein one channel of the syringe is filled with a fibrinogen solution C1 containing modified nano-hydroxyapatite / degradable polyester composite microspheres with a core-shell structure and sulfonated chitosan, and the other channel of the syringe is filled with a thrombin solution C2, and the solutions in the two channels of the syringe are simultaneously and evenly injected into the defect site, and a gel is rapidly formed at the defect site to fill and repair the defect site.

11. The application according to claim 10, wherein In the two channels of the syringe, the volume ratio of the fibrinogen solution C1 to the thrombin solution C2 is (1 to 10):1, preferably (1 to 5):1.

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