A photothermal functionalized decalcified bone matrix material and its preparation method and application

Abstract

The embodiments of the present invention disclose a photothermally functionalized decalcified bone matrix material, a preparation method, and an application thereof. The photothermally functionalized decalcified bone matrix material includes a decalcified bone matrix material and photothermally functional nanoparticles loaded on the decalcified bone matrix material. The allogeneic decalcified bone matrix is ​​used as a substrate, and hollow mesoporous manganese dioxide nanoparticles loaded with an antibacterial agent are coated on the surface of the allogeneic decalcified bone matrix via polydopamine. The hollow mesoporous manganese dioxide has a typical hollow mesoporous structure, a good pore structure, and an ultra-high specific surface area, and can effectively load antibacterial agents such as chlorhexidine. The decalcified bone matrix material with a photothermal effect can rapidly convert light energy into heat energy to kill bacteria under irradiation of near-infrared light, and can control the release of antibacterial agents to improve bactericidal performance. At the same time, the manganese ions produced by the decomposition of manganese dioxide and the decalcified bone matrix can promote bone defect repair, and is expected to play a huge role in the future clinical treatment of infectious bone defects.

Description

Technical Field

[0001] The present invention belongs to the field of biomedical materials, and in particular relates to a decalcified bone matrix material with photothermal effect, a preparation method thereof, and an application thereof. Background Art

[0002] Repairing infected bone defects remains a major medical challenge for orthopedic surgeons worldwide. Despite significant advances in medical technology, the high failure rate of treatment makes repairing infected bone defects a difficult clinical challenge. Unlike typical bone defects, infected bone defects can pose a risk of amputation if improperly managed.

[0003] Currently, there are multiple approaches to treating infected bone defects. Traditionally, these include thorough debridement and adjunctive antibiotic therapy, the Ilizarov technique, and the Masquelet technique. The Ilizarov technique is based on the tension-stress principle. Using an external fixator, osteotomies are performed at the proximal and distal ends of the bone defect. This involves continuous, steady, and slow traction of the living tissue, and the transfer of free bone segments to the defect site. This activates the regeneration of certain tissue cells, gradually forming trabeculae, and ultimately achieving ossification, thereby repairing the bone defect. The Masquelet technique involves a two-stage procedure. The first stage involves debridement to remove infected and necrotic tissue, followed by the placement of a bone cement spacer within the defect area to eliminate the dead space. A membrane-forming membrane forms on the spacer surface, closing the wound. The second stage, after the infection has been controlled, involves surgical removal of the bone cement and the implantation of autologous cancellous bone within the membrane to form new, viable bone, ultimately remodeling the defect. Currently, there is insufficient evidence to determine which surgical approach is most effective.

[0004] Currently, there are two main treatment principles for infected bone defects: 1. Prioritize the treatment of bone defects, and then mobilize the body's immune system to naturally eliminate bone infection by healing the bone defect; 2. Prioritize the treatment of bone infection, create a sterile bone defect environment conducive to osteogenesis, and then perform bone defect treatment. Based on this, methods that use bioscaffold materials as the core to repair infected bone defects have gradually emerged. Bioscaffold materials have excellent bactericidal ability, strong mechanical properties, and strong osteoinduction ability, giving them a huge advantage in the treatment of infected bone defects. The ideal bioscaffold needs to have the following characteristics: 1. Excellent mechanical support; 2. Osteoconduction; 3. Osteoinduction; 4. Good biocompatibility; 5. Sustained antibacterial effect.

[0005] Allogeneic demineralized bone matrix (DBM) is a commonly used allograft material in clinical practice. Decalcification exposes BMP-2 protein in bone tissue, inducing the transformation of osteoprogenitor cells into chondrogenic and osteoblastic cells, thereby inducing osteogenesis. Allogeneic demineralized bone matrix has a natural porous structure and possesses considerable mechanical strength, making it an excellent bioscaffold material. Near-infrared (NIR)-induced photothermal materials have shown significant advantages in anti-infection. Hollow mesoporous manganese dioxide-based photothermal materials can convert light energy into heat energy under NIR irradiation. Furthermore, their unique skeletal structure, rich internal pores, and biodegradability allow them to be loaded with antimicrobial agents and continuously release them under NIR irradiation, demonstrating excellent photothermal and bactericidal effects. Furthermore, mesoporous manganese dioxide degrades in vivo to produce manganese ions, which promote osteogenesis. Therefore, it is of great significance to develop a decalcified bone matrix material with photothermal effect, which has good biocompatibility, low toxicity and side effects, and excellent antibacterial properties. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides the following technical solution: a photothermal functionalized decalcified bone matrix material, which includes a decalcified bone matrix material and photothermal functional nanoparticles loaded on the decalcified bone matrix material.

[0007] Preferably, the following steps are included:

[0008] S1. Allogeneic bone is prepared into regular bone strips, which are then high-pressure washed, degreased, and air-dried before being decalcified to produce decalcified bone blocks;

[0009] S2, using silica spheres as templates and potassium permanganate as a manganese source to prepare mesoporous manganese dioxide nanoparticles with silica as the core, etching the product with alkaline solution, washing it, and vacuum freeze-drying it to obtain hollow mesoporous manganese dioxide nanoparticles;

[0010] S3, dispersing the obtained hollow mesoporous manganese dioxide nanoparticles in DMSO, adding an antibacterial agent, stirring, and then centrifuging to collect the product to obtain nanoparticles CHMO loaded with the antibacterial agent;

[0011] S4, dispersing the obtained CHMO nanoparticles in methanol, adding a phase change agent, stirring, and then centrifuging to collect the product to obtain capped nanoparticles LCHMO;

[0012] S5. The obtained nanoparticles LCHMO are dispersed in a Tris-HCl solution, dopamine hydrochloride and decalcified bone pieces are added, and after stirring, the product is collected, washed, and then freeze-dried to obtain the photothermal functionalized decalcified bone matrix material PLCHMO-DBM.

[0013] Preferably, the particle size of the hollow mesoporous manganese dioxide in the photothermal functional nanoparticles in step S2 is 60-400 nanometers.

[0014] Preferably, the decalcification solution in step S5 is dilute hydrochloric acid prepared by mixing concentrated hydrochloric acid and purified water in a volume ratio of 0.5 to 2:20, the mass ratio of decalcified bone pieces to decalcification solution is 1 to 5:20, the temperature is 20 to 40 degrees Celsius, and the time is 12 to 48 hours.

[0015] Preferably, the method for preparing the hollow mesoporous manganese dioxide in step S2 is to disperse the prepared dioxide nanoparticles in a potassium permanganate solution, perform sonication, stir in the dark at room temperature, and vacuum dry to obtain mesoporous manganese dioxide nanoparticles with silicon dioxide as the core; then, use alkaline solution to etch the silicon dioxide core, and then perform centrifugation and vacuum freeze-drying to obtain hollow mesoporous manganese dioxide nanoparticles.

[0016] Preferably, the phase change agent in step S4 is any one of lauric acid and capric acid, which can change its state with temperature.

[0017] Preferably, the antibacterial agent in step S3 is any one of vancomycin, tetracycline, quinolones, chlorhexidine, and polyhexamethylene biguanide.

[0018] Preferably, the photothermal functional nanoparticles are capped nanoparticles LCHMO coated on the surface of the decalcified bone fragments through polydopamine; the polydopamine is formed by hydrolyzing dopamine hydrochloride in Tris-HCl.

[0019] The embodiment of the present invention provides the use of the photothermal functionalized decalcified bone matrix material prepared by the above-mentioned preparation method in materials for infectious bone defects and repair.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. Simple preparation process and good biocompatibility;

[0022] 2. Using the same decalcified bone matrix as the base material, it has good osteoinductivity and biomechanical properties;

[0023] 3. Using hollow mesoporous manganese dioxide to load antimicrobial agents can quickly convert light energy into heat energy to kill bacteria, while also controlling the release of antimicrobial agents to improve bactericidal performance. At the same time, the manganese ions produced by the decomposition of manganese dioxide and the decalcified bone matrix can promote bone defect repair.

[0024] 4. Polydopamine not only improves the biocompatibility of mesoporous manganese dioxide materials, but also improves the photothermal conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the synthesis of the photothermal functionalized decalcified bone matrix material prepared in the present invention.

[0026] Figure 2 This is the SEM image of the hollow mesoporous manganese dioxide prepared in the present invention.

[0027] Figure 3 This is a photothermal effect diagram of the photothermal functional nanoparticles (PLCHMO) prepared in the present invention.

[0028] Figure 4 These are optical photographs of different photothermal functionalized decalcified bone matrix materials PLCHMO-DBM prepared in Example 3 of the present invention.

[0029] Figure 5 The cytotoxicity graphs of hollow mesoporous manganese dioxide nanoparticles (HMO) with different concentrations, nanoparticles CHMO loaded with antibacterial agents, capped nanoparticles LCHMO, and photothermal functional nanoparticles PLCHMO prepared in the present invention are shown.

[0030] Figure 6 Biocompatibility diagram of the photothermal functionalized decalcified bone matrix material PLCHMO-DBM prepared in different embodiments of the present invention.

[0031] Figure 7 Antibacterial effect diagram of PLCHMO-DBM prepared in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] The photothermal functionalized decalcified bone matrix material comprises a decalcified bone matrix material and photothermal functional nanoparticles loaded on the decalcified bone matrix material.

[0034] The following steps are involved:

[0035] S1. Allogeneic bone is prepared into regular bone strips, which are then high-pressure washed, degreased, and air-dried before being decalcified to produce decalcified bone blocks;

[0036] S2, using silica spheres as templates and potassium permanganate as a manganese source to prepare mesoporous manganese dioxide nanoparticles with silica as the core, etching the product with alkaline solution, washing it, and vacuum freeze-drying it to obtain hollow mesoporous manganese dioxide nanoparticles;

[0037] S3, dispersing the obtained hollow mesoporous manganese dioxide nanoparticles in DMSO, adding an antibacterial agent, stirring, and then centrifuging to collect the product to obtain nanoparticles CHMO loaded with the antibacterial agent;

[0038] S4, dispersing the obtained CHMO nanoparticles in methanol, adding a phase change agent, stirring, and then centrifuging to collect the product to obtain capped nanoparticles LCHMO;

[0039] S5. The obtained nanoparticles LCHMO are dispersed in a Tris-HCl solution, dopamine hydrochloride and decalcified bone pieces are added, and after stirring, the product is collected, washed, and then freeze-dried to obtain the photothermal functionalized decalcified bone matrix material PLCHMO-DBM.

[0040] The particle size of the hollow mesoporous manganese dioxide in the photothermal functional nanoparticles in step S2 is 60-400 nanometers.

[0041] The decalcification solution in step S5 is dilute hydrochloric acid prepared by mixing concentrated hydrochloric acid and purified water in a volume ratio of 0.5 to 2:20. The ratio of decalcified bone pieces to decalcification solution is 1 to 5:20 by mass. The temperature is 20 to 40 degrees Celsius and the time is 12 to 48 hours.

[0042] The preparation method of hollow mesoporous manganese dioxide in step S2 is to disperse the prepared dioxide nanoparticles in a potassium permanganate solution, and obtain mesoporous manganese dioxide nanoparticles with silicon dioxide as the core by ultrasonication, stirring at room temperature in the dark, and vacuum drying; then, the silicon dioxide core is etched with alkaline solution, and then centrifuged and vacuum freeze-dried to obtain hollow mesoporous manganese dioxide nanoparticles.

[0043] The phase change agent in step S4 is either lauric acid or capric acid, which can change its state with temperature.

[0044] The antibacterial agent in step S3 is any one of vancomycin, tetracycline, quinolones, chlorhexidine, and polyhexamethylene biguanide.

[0045] The photothermal functional nanoparticles are coated on the surface of the decalcified bone fragments with the capped nanoparticles LCHMO through polydopamine; polydopamine is prepared by hydrolysis of dopamine hydrochloride in Tris-HCl.

[0046] Example 1:

[0047] Inventive method for preparing photothermal functionalized decalcified bone matrix material:

[0048] Allogeneic bone is prepared into regular bone strips, which are then high-pressure washed, degreased, and air-dried before decalcification. The decalcification solution is a mixture of concentrated hydrochloric acid and purified water at a volume ratio (v / v) of (0.5-2):20. The ratio of bone fragments to decalcification solution is 1-5:20 by mass. The temperature is 20-40°C, and the decalcification time is 12-48 hours.

[0049] Using silica spheres as templates, the prepared manganese dioxide nanoparticles were dispersed in a potassium permanganate solution. After uniform stirring, the solution was sonicated for 2 hours. The solution was then stirred at room temperature in the dark for 12-24 hours and then freeze-dried in a vacuum oven to obtain mesoporous manganese dioxide nanoparticles with silica as the core. The solution was then stirred in a 0.4M sodium carbonate solution at 40-60°C for 12-24 hours, centrifuged, and freeze-dried in a vacuum oven to obtain hollow mesoporous manganese dioxide nanoparticles (HMO). For example, the mass ratio of silica spheres to potassium permanganate ranged from 0.5:1 to 2:1. Alkaline etching was performed at 50°C for 24 hours. The vacuum freeze-drying time was 12 hours.

[0050] The resulting hollow mesoporous manganese dioxide nanoparticles (HMO) were dispersed in 10 mL of DMSO. Chlorhexidine was added and stirred for 12-24 hours. The product was then centrifuged, washed, and freeze-dried to obtain chlorhexidine-loaded nanoparticles (CHMO). As an example, the volume of DMSO can be 10 mL. The mass ratio of hollow mesoporous manganese dioxide nanoparticles to chlorhexidine was 2-5:1, and the stirring time was 24 hours.

[0051] The resulting CHMO nanoparticles are dispersed in 10 mL of methanol. Lauric acid (a phase change agent) is added and stirred at room temperature for 12-24 hours. The product is then washed, collected by centrifugation, and freeze-dried to obtain capped LCHMO nanoparticles. For example, the volume of methanol can be 10 mL. The mass ratio of nanoparticles to lauric acid is 1-2:1.

[0052] The resulting LCHMO nanoparticles are dispersed in a Tris-HCl solution. Dopamine hydrochloride and decalcified bone fragments are added. Stir at room temperature in the dark for 12-24 hours. The product is then collected, washed, and freeze-dried to produce the photothermally functionalized decalcified bone matrix material, PLCHMO-DBM. For example, the concentration of the Tris-HCl solution is 10 mM. The volume of the solution is 20 mL. The mass ratio of dopamine hydrochloride to LCHMO nanoparticles is between 0.4 and 1:1. The mass ratio of decalcified bone fragments to LCHMO nanoparticles is between 2 and 5:1.

[0053] Example 2:

[0054] 1.57 ml of ammonia water, 3 ml of ethyl orthosilicate, 60 mg of dopamine hydrochloride, 0.05 g of chlorhexidine, 0.01 g of lauric acid, 10 ml of methanol, and 10 ml of dimethyl sulfoxide were purchased from Adamas Reagent Company. 35.7 ml of anhydrous ethanol, 0.4 ml of sodium carbonate, and 300 mg of potassium permanganate were purchased from Sinopharm Chemical Reagent Co., Ltd. MTT was purchased from Sigma under the name of thiazolyl blue.

[0055] 1. Preparation method of hollow mesoporous manganese dioxide nanoparticles HMO:

[0056] Mix 35.7 mL of anhydrous ethanol with 5 mL of deionized water and 1.57 mL of ammonia water, add 3 mL of TEOS, stir rapidly at 30 ° C for 2 hours, centrifuge to collect the product, wash it three times with ethanol and deionized water, and freeze-dry it to obtain silica nanoparticles. Take 0.5 g of silica nanoparticles and disperse them in 20 mL of purified water, add 300 mg of potassium permanganate, ultrasonicate for 2 hours, stir at room temperature for 24 hours, centrifuge, wash and freeze-dry to obtain mesoporous manganese dioxide nanoparticles with silica as the core. Disperse 0.2 g of the above nanoparticles in 0.4 ml of sodium carbonate solution, stir at 50 ° C for 24 hours, centrifuge, wash and freeze-dry to obtain hollow mesoporous manganese dioxide nanoparticles HMO with a particle size of 60-400 nm. Figure 2 shown.

[0057] 2. Preparation method of photothermal functional nanoparticles PLCHMO:

[0058] 0.1 g of hollow mesoporous manganese dioxide nanoparticles (HMO) were dispersed in 10 mL of DMSO, and 0.05 g of chlorhexidine was added. After stirring for 24 h, the product was collected by centrifugation, washed, and freeze-dried to obtain chlorhexidine-loaded nanoparticles CHMO.

[0059] 0.01 g CHMO nanoparticles were dispersed in 10 mL methanol, 0.01 g lauric acid as a phase change agent was added, and the mixture was stirred at room temperature for 24 h. The product was washed and collected by centrifugation, and then freeze-dried to obtain capped nanoparticles LCHMO.

[0060] 3. Preparation method of photothermal functionalized decalcified bone matrix material PLCHMO-DBM:

[0061] 0.01g of LCHMO nanoparticles was dispersed in 20ml of a 10mM Tris-HCl solution, and 20mg of dopamine hydrochloride was added. The mixture was stirred in the dark at room temperature for 24 hours, and then the product was collected, washed, and freeze-dried to obtain the photothermally functionalized PLCHMO nanoparticles. The prepared photothermally functionalized PLCHMO nanoparticles were redispersed in purified water, and small pieces of decalcified bone were added. After slow stirring at room temperature for 12 hours, the material was washed and freeze-dried to obtain the photothermally functionalized decalcified bone matrix material PLCHMO-DBM, labeled with PD-1.

[0062] 0.01 g of LCHMO nanoparticles were dispersed in 20 ml of 10 mm Tris-HCl solution, 20 mg of dopamine hydrochloride was added, and the mixture was stirred in the dark at room temperature for 6 h. Then, small pieces of decalcified bone were added. The mixture was slowly stirred at room temperature for 18 h, washed, and freeze-dried to obtain the photothermally functionalized decalcified bone matrix material PLCHMO-DBM, which was labeled as PD-2.

[0063] 0.01 g of LCHMO nanoparticles were dispersed in 20 ml of 10 mm Tris-HCl solution, 20 mg of dopamine hydrochloride was added, and small pieces of decalcified bone were added. After slow stirring at room temperature for 24 h, the material was washed and freeze-dried to obtain the photothermally functionalized decalcified bone matrix material PLCHMO-DBM, which was labeled as PD-3.

[0064] like Figure 4 As shown, a is a small piece of decalcified bone, b is PD-1, c is PD-2, and d is PD-3. The color of the photothermal functionalized decalcified bone matrix materials prepared by the three methods gradually deepens.

[0065] The cytotoxicity of hollow mesoporous manganese dioxide nanoparticles (HMO), antimicrobial-loaded nanoparticles (CHMO), capped nanoparticles (LCHMO), and photothermal-functionalized nanoparticles (PLCHMO) was evaluated using the MTT assay. MTT is a powdered chemical reagent known as 3-(4,5-Dimethyl-2-Thiazol-2-yl)-2,5-Diphenyl-2H-Tetrazolium Bromide (MTT), also known as 3-(4,5-Dimethyl-2-thiazol-2,5-diphenyltetrazolium bromide in Chinese and trade name: Thiazolium Blue). The MTT assay is a method for assessing cell viability and growth. The assay works by activating the enzyme succinate dehydrogenase in the mitochondria of living cells to reduce exogenous MTT to water-insoluble, blue-purple crystalline formazan, which is deposited in the cells. However, this reduction is not observed in dead cells. Isopropyl alcohol dissolves formazan in cells. Its absorbance is measured at 570 nm using a microplate reader. Within a certain cell population range, the amount of MTT crystals formed is proportional to the cell number. The measured absorbance (OD value) is used to determine the number of viable cells; a higher OD value indicates greater cell viability.

[0066] The cytotoxicity of hollow mesoporous manganese dioxide nanoparticles (HMO), nanoparticles loaded with antimicrobial agents CHMO, capped nanoparticles LCHMO, and photothermal functional nanoparticles PLCHMO at different concentrations on mouse somatic cells L929 was determined in vitro. Figure 5 As shown, after 24 hours of co-culture with different concentrations of HMO, CHMO, LCHMO, and PLCHMO, L929 cells showed significant differences in cell viability. When HMO and PLCHMO were co-cultured with L929 cells, cell viability remained above 90%, even at a powder concentration of 100 μg / mL, demonstrating good cytocompatibility between HMO and PLCHMO. Furthermore, when CHMO was co-cultured with L929 cells, cell viability increased to 98.45%, 85.42%, 91.57%, and 89.41% at powder concentrations of 10, 20, 50, and 100 μg / mL, respectively. This may be due to the cytotoxicity of the antimicrobial agent chlorhexidine released from the capped LCHMO. Cell viability remained around 75% for L929 cells, likely due to the cytotoxicity of lauric acid.

[0067] The evaluation of the above materials is as follows:

[0068] 1. Cytotoxicity evaluation of photothermally functionalized decalcified bone matrix material PLCHMO-DBM:

[0069] The specific implementation method is to use the MTT method to detect the cytotoxicity of the extracts of decalcified bone matrix DBM and photothermally functionalized decalcified bone matrix materials PD-1, PD-2, and PD-3 in vitro. 1g of DBM, PD-1, PD-2, and PD-3 were taken, added to 10ml of culture medium, incubated at 37°C for 24h, and then the extracts were co-cultured with L929 cells to detect the cell survival rate. Figure 6 As shown in the figure, the cell survival rate was above 90%, indicating that the photothermal functionalized decalcified bone matrix material PLCHMO-DBM has good cell compatibility.

[0070] 2. Evaluation of the photothermal effect of photothermal functionalized decalcified bone matrix material PLCHMO-DBM:

[0071] Take the PD-3 material under 808nm near-infrared irradiation, and test its temperature change curves over time in dry state and PBS buffer environment, as shown in Figure 2. Figure 3 As shown, the PD-3 material exhibited obvious photothermal effect in both dry state and dry state and PBS buffer environment.

[0072] 3. Evaluation of the antibacterial effect of photothermal functionalized decalcified bone matrix material PLCHMO-DBM:

[0073] 0.2g of DBM and PD-3 (2 small bone pieces) were fully contacted with 1mL of Escherichia coli (bacterial concentration was 2×104 CFU / mL) and irradiated under 808nm near-infrared light for 10 minutes. Then 50μL was taken to spread on the plate and incubated at 37℃ for 24 hours before taking pictures. Figure 7 As shown, the DBM group showed no significant changes compared with the blank group, while the PD-3 group showed significant antibacterial properties.

[0074] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a photothermal functionalized decalcified bone matrix material, characterized by: The following steps are involved: S1. Prepare allogeneic bone into regular bone strips, which are then decalcified after high-pressure washing, degreasing and drying to make decalcified bone pieces; S2. Use silica spheres as templates and potassium permanganate as manganese source to prepare mesoporous manganese dioxide nanoparticles with silica as the core, and etch the product with alkali solution, separate it, wash it, and freeze-dry it in vacuum to obtain hollow mesoporous manganese dioxide nanoparticles; S3. Disperse the obtained hollow mesoporous manganese dioxide nanoparticles in DMSO, add an antibacterial agent, stir it, and then centrifuge to collect the product to obtain nanoparticles CHMO loaded with an antibacterial agent; S4. Disperse the obtained CHMO nanoparticles in methanol, add a phase change agent, stir it, and then centrifuge to collect the product to obtain capped nanoparticles LCHMO; S5. Disperse the obtained nanoparticles LCHMO in a Tris-HCl solution, add dopamine hydrochloride and decalcified bone pieces, stir it, collect the product, wash it, and then freeze-dry it to obtain a photothermally functionalized decalcified bone matrix material PLCHMO-DBM.

2. The method for preparing a photothermal functionalized decalcified bone matrix material according to claim 1, characterized in that: The particle size of the hollow mesoporous manganese dioxide nanoparticles in step S2 is 60-400 nanometers.

3. The method for preparing a photothermal functionalized decalcified bone matrix material according to claim 1, characterized in that: The decalcification solution used in step S1 is dilute hydrochloric acid prepared by mixing concentrated hydrochloric acid and purified water in a volume ratio of 0.5 to 2:

20. The mass ratio of the decalcified bone pieces to the decalcification solution is 1 to 5:

20. The temperature is 20 to 40 degrees Celsius and the time is 12 to 48 hours.

4. The method for preparing a photothermal functionalized decalcified bone matrix material according to claim 1, wherein: The method for preparing the hollow mesoporous manganese dioxide in step S2 is to disperse the prepared silica spheres in a potassium permanganate solution, and prepare mesoporous manganese dioxide nanoparticles with silica as the core by ultrasonication, stirring at room temperature in the dark, and vacuum drying; then, the silica core is etched with alkaline solution, and then centrifuged and vacuum freeze-dried to obtain the hollow mesoporous manganese dioxide nanoparticles.

5. The method for preparing a photothermal functionalized decalcified bone matrix material according to claim 1, characterized in that: The phase change agent in step S4 is either lauric acid or capric acid, which can change its state with temperature.

6. The method for preparing a photothermal functionalized decalcified bone matrix material according to claim 1, characterized in that: The antibacterial agent in step S3 is any one of vancomycin, tetracycline, quinolones, chlorhexidine, and polyhexamethylene biguanide.

7. The method for preparing a photothermal functionalized decalcified bone matrix material according to claim 1, characterized in that: In step S5, dopamine hydrochloride is hydrolyzed in Tris-HCl to form polydopamine, which coats the surface of the decalcified bone fragment with the capped nanoparticles LCHMO.

8. Use of the photothermal functionalized decalcified bone matrix material prepared by the preparation method according to any one of claims 1 to 7 in the preparation of materials for infectious bone defects and repair.

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