3D printing PCL / nHA combined bionic glycopeptide hydrogel stent for replacement of infected bone defect and preparation method of 3D printing PCL / nHA combined bionic glycopeptide hydrogel stent

Abstract

The invention discloses a 3D printing PCL / nHA combined bionic glycopeptide hydrogel scaffold for infected bone defect substitution and a preparation method thereof, and belongs to the field of biomedical materials. The scaffold comprises a 3D printed PCL / nHA porous scaffold, the 3D printed PCL / nHA porous scaffold is provided with three-dimensional interconnected micro-channels, the mass percentage of nHA is 10-30wt%, the scaffold is further filled with a bionic glycopeptide hydrogel layer formed by mixing methylacryloylated gelatin, aldehyde bletilla striata polysaccharide, antibacterial peptide and a photoinitiator according to the ratio of 10: 4: 2: 1 and carrying out ultraviolet irradiation polymerization, phenyl lithium phosphate is adopted as the photoinitiator, and the bionic glycopeptide hydrogel layer is a bionic glycopeptide hydrogel layer. And 3D printing process parameters are accurately controlled. The preparation method comprises the steps of PCL / nHA porous scaffold preparation, pretreatment, finished product treatment, bionic glycopeptide hydrogel solution preparation, filling polymerization and the like. The scaffold disclosed by the invention integrates excellent mechanical properties, biocompatibility, antibacterial and anti-inflammatory capabilities and strong bone induction biological activity, provides an ideal material for repairing infected bone defects, and effectively overcomes many defects of a traditional skull repairing material.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and in particular to a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects and a preparation method thereof. Background Art

[0002] The treatment of traumatic skull defects has always been a very challenging problem in the medical field. In the process of skull repair, it is necessary not only to achieve precise structural reconstruction, but also to protect the fragile brain tissue from secondary damage in all aspects. Traditional skull repair materials, such as metal materials and ceramic materials, generally have the disadvantages of poor elasticity and low osteogenic activity, which are difficult to match the physiological characteristics of human bone tissue, and thus cannot provide an ideal microenvironment for bone defect repair. What is even more tricky is that these traditional materials lack effective antibacterial activity. When faced with bone defects caused by open trauma, they are very likely to cause stubborn bacterial infections, which seriously hinders the healing process of the bone defect.

[0003] At the same time, although the addition of harmful antibiotics can inhibit bacterial growth to a certain extent, it has caused many negative effects. On the one hand, the long-term use of antibiotics has spawned drug-resistant bacteria, increasing the difficulty of infection prevention and control; on the other hand, the addition of antibiotics inevitably destroys the original physical and chemical properties of the scaffold material, causing its osteogenic performance to be greatly reduced, further delaying the repair cycle of bone defects.

[0004] With the rapid development of biomaterials science, bionic glycopeptide hydrogel scaffolds have emerged. This type of scaffold cleverly simulates the physical and chemical properties of natural bone extracellular matrix, and from microstructure to biological function, it has opened up a new path for the regeneration and repair of bone defects. It can accurately regulate the adhesion, proliferation and differentiation of cells, providing excellent basic conditions for the formation of new bone tissue. In addition, the combination of advanced 3D printing technology and photocuring methods can be used to highly biomimetic design of the complex internal structure of infected bone defects. With its excellent precision, 3D printing technology can perfectly reproduce the fine structure and unique functions of various biological tissues. The prepared polymer fibers have both excellent mechanical properties and good biocompatibility, can effectively bear physiological loads and coexist harmoniously with surrounding tissues. The photocured glycopeptide hydrogel exhibits excellent anti-swelling properties and excellent elasticity, ensuring that the scaffold maintains a stable morphology and function in a complex in vivo environment. The 3D printed scaffold constructed by the two together combines rapid antibacterial and anti-inflammatory capabilities with strong bone-inducing biological activity. Without relying on any drugs, exogenous growth factors or seed cells, it presents a highly promising candidate for the reconstruction of large-scale bone damage, and is expected to overcome the many difficulties in repairing infected bone defects. Summary of the invention

[0005] The present invention mainly aims at the problems of poor elasticity, low osteogenic activity, lack of antibacterial activity, and traditional treatment methods that are easy to induce drug-resistant bacteria and reduce the osteogenic performance of the scaffold in existing skull repair materials. A 3D printed PCL / nHA combined bionic glycopeptide hydrogel scaffold for replacing infected bone defects and a preparation method thereof are provided.

[0006] The purpose of the present invention is mainly achieved through the following solutions: In a first aspect, the present application provides a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects, comprising: 3D printed PCL / nHA porous scaffolds having three-dimensional interconnected microchannels, wherein a mixture of PCL and nHA is used as the printing material, wherein the mass percentage of nHA is 10wt%-30wt%; The biomimetic glycopeptide hydrogel layer filled in the PCL / nHA porous scaffold is prepared by mixing methacrylylated gelatin, aldehyde-modified bletilla striata polysaccharide, antimicrobial peptide and photoinitiator and polymerizing them under ultraviolet light irradiation.

[0007] Preferably, the dimensional parameters of the PCL / nHA porous scaffold during 3D printing are: diameter 5-7 mm, thickness 0.8-1.2 mm; molding temperature 170-185° C., and nozzle diameter 0.2 mm.

[0008] Preferably, the diameter of the three-dimensional interconnected microchannels of the PCL / nHA porous scaffold is 300 μm.

[0009] Preferably, the mass ratio of the methacryloylated gelatin, the aldehyded Bletilla striata polysaccharide, the antimicrobial peptide and the photoinitiator is 10:4:2:1.

[0010] Preferably, the photoinitiator is phenyl (2,4,6-trimethylbenzoyl) lithium phosphate.

[0011] In a second aspect, the present application provides a method for preparing a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects, comprising the following steps: Step 1, preparing a PCL / nHA porous scaffold, preparing a mixture of PCL and nHA powder as 3D printing ink, using computer-aided design software to design a PCL / nHA implant pattern with a three-dimensional interconnected microchannel structure, and printing the PCL / nHA porous scaffold through 3D printing technology in conjunction with an FDM system; Step 2: Pretreatment of the PCL / nHA porous scaffold: placing the PCL / nHA porous scaffold prepared in step 1 into a 5 mol / L sodium hydroxide solution and subjecting it to surface treatment at 37° C. under shaking conditions for 1-2 h; Step 3, finished product treatment of the PCL / nHA porous scaffold, rinsing the PCL / nHA porous scaffold treated in step 2 with deionized water and drying; Step 4, preparing a biomimetic glycopeptide hydrogel solution, first weighing methacrylylated gelatin, aldehyde-modified Bletilla striata polysaccharide and antimicrobial peptide into a centrifuge tube, adding 500 μL of deionized water, vortexing to completely dissolve them, adding a photoinitiator, passing nitrogen for 10-20 minutes, and obtaining a uniform mixed solution after deoxygenation; Step 5: Add the biomimetic glycopeptide hydrogel solution obtained in step 4 to the PCL / nHA porous scaffold treated in step 3, irradiate under ultraviolet light for free radical polymerization, obtain a PCL / nHA combined biomimetic glycopeptide hydrogel scaffold, and store it in a low-temperature sterile environment.

[0012] Preferably, the mass percentage of nHA in the ink in step 1 is between 10wt% and 30wt%.

[0013] Preferably, the diameter of the three-dimensional interconnected microchannels in the PCL / nHA implant pattern is 300 μm, and the dimensional parameters during 3D printing are: PCL / nHA porous scaffold diameter 5-7 mm, thickness 0.8-1.2 mm; molding temperature 170-185° C., nozzle diameter 0.2 mm.

[0014] Preferably, in step 4, the mass ratio of methacryloylated gelatin, aldehyded Bletilla striata polysaccharide, antimicrobial peptide and photoinitiator is 10:4:2:1, and the photoinitiator is phenyl (2,4,6-trimethylbenzoyl) lithium phosphate.

[0015] Preferably, the ultraviolet light irradiation time in step 5 is 10-20 minutes.

[0016] Therefore, compared with the prior art, the present invention has the following advantages: (1) The 3D printed PCL / nHA porous scaffold provided by the present invention has a regular fiber structure and good mechanical strength, which can effectively resist the external force impact under the physiological environment and provide stable support for the bone defect site. At the same time, the PCL material itself has excellent biocompatibility, which can promote cell adhesion and proliferation, coexist harmoniously with human tissues, reduce immune rejection reactions, and create favorable conditions for bone repair; (2) The 3D printed PCL / nHA porous scaffold of the present invention has three-dimensional interconnected microchannels with a diameter precisely controlled at 300 μm. This structure highly simulates the microscopic pore structure of natural bone tissue, which is conducive to the transmission of nutrients, the discharge of metabolic waste, and the migration and colonization of cells, creating an ideal microenvironment for the regeneration of bone defect areas and accelerating the bone healing process; (3) The biomimetic glycopeptide hydrogel layer filled inside the PCL / nHA porous scaffold of the present invention incorporates antimicrobial peptide components, which can specifically identify and act on pathogens, destroy bacterial cell membranes or interfere with their metabolic processes, achieve high-efficiency antibacterial properties, effectively prevent and control bacterial growth in infected bone defects, reduce the risk of postoperative infection, and help bone defect repair proceed smoothly; (4) nHA in the present invention is an important inorganic component of bone tissue, has good osteoconductivity, can provide sites for calcium and phosphate deposition, and induce bone cell attachment and differentiation; in addition, the aldehyde-modified Bletilla striata polysaccharide in the biomimetic glycopeptide hydrogel layer can regulate cell behavior, synergistically promote the secretion of osteogenic-related cytokines, stimulate the regeneration potential of bone tissue, and significantly improve the success rate of bone defect repair; (5) The finished stent provided by the present invention is prepared based on photocuring, which ensures that the biomimetic glycopeptide hydrogel layer has excellent anti-swelling properties, so that it can still maintain a stable structure and function under the complex physiological environment in the body, ensuring that the stent can function effectively for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a comparison diagram before and after the photocuring of the biomimetic glycopeptide GBE hydrogel in the present invention and a diagram of the internal structure of the hydrogel; Figure 2 It is a microscopic morphology and element distribution picture of nano-hydroxyapatite nHA in the present invention; Figure 3 This is a microscopic morphology picture of the biomimetic glycopeptide GBE hydrogel in the present invention; Figure 4 It is a comparison chart of the microstructure and mechanical properties test of each group of materials in the present invention; Figure 5 It is a graph showing the results of the antibacterial experiment of different substances in the present invention on Staphylococcus aureus and Escherichia coli; Figure 6 This is a graph of the activity of bone marrow mesenchymal stem cells measured using the CCK-8 method and different materials in the present invention; Figure 7 This is a live-dead staining diagram of bone marrow mesenchymal stem cells after being treated with each group of materials in the present invention for 24 hours; Figure 8 It is a CT image of a representative rat skull 8 weeks after being treated with different materials in the present invention. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any form of modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0019] In the present invention, unless otherwise specified, all parts and percentages are weight units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art. The components or equipment in the following embodiments, unless otherwise specified, are universal standard parts or components known to those skilled in the art, and their structures and principles are known to those skilled in the art through technical manuals or conventional experimental methods.

[0020] The present application embodiment discloses a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects, comprising: 3D printed PCL / nHA porous scaffolds having three-dimensional interconnected microchannels, wherein a mixture of PCL and nHA is used as the printing material, wherein the mass percentage of nHA is 10wt%-30wt%; The biomimetic glycopeptide hydrogel layer filled in the PCL / nHA porous scaffold is prepared by mixing methacrylylated gelatin, aldehyde-modified bletilla striata polysaccharide, antimicrobial peptide and photoinitiator and polymerizing them under ultraviolet light irradiation.

[0021] Specifically, the dimensional parameters of the PCL / nHA porous scaffold during 3D printing are: diameter 5-7 mm, thickness 0.8-1.2 mm; molding temperature 170-185°C, nozzle diameter 0.2 mm, preferably diameter 6 mm, thickness 1 mm, and molding temperature 180°C.

[0022] Specifically, the diameter of the three-dimensional interconnected microchannels of the PCL / nHA porous scaffold is 300 μm.

[0023] Specifically, the mass ratio of methacryloylated gelatin, aldehyded bletilla striata polysaccharide, antimicrobial peptide and photoinitiator is 10:4:2:1.

[0024] Specifically, the photoinitiator is phenyl (2,4,6-trimethylbenzoyl) lithium phosphate.

[0025] PCL is poly(ε-caprolactone) and nHA is nano-hydroxyapatite.

[0026] The present application also discloses a method for preparing a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects, comprising the following steps: Step 1, prepare PCL / nHA porous scaffold, prepare a mixture of PCL and nHA powder as 3D printing ink, use computer-aided design software to design a PCL / nHA implant figure with a three-dimensional interconnected microchannel structure, and use 3D printing technology and FDM system to print out the PCL / nHA porous scaffold. In the specific operation, the computer-aided design software uses Magics, Materialise, Belgium; the 3D printer uses Livprint® N series, Medprin Regenerative Medicine Technology Co., Ltd., Guangzhou, China; the printing platform is heated to 180°C, the mixed ink is placed in the 3D printer barrel, and fused deposition molding 3D printing is performed through a nozzle with a diameter of 0.2 mm. After printing is completed, the PCL / nHA porous scaffold is taken out from the molding chamber.

[0027] Step 2: Pretreatment of the PCL / nHA porous scaffold: placing the PCL / nHA porous scaffold prepared in step 1 into a 5 mol / L sodium hydroxide solution and subjecting it to surface treatment at 37° C. under shaking conditions for 1-2 h; Step 3: Finished product treatment of PCL / nHA porous scaffold: rinse the PCL / nHA porous scaffold treated in step 2 with deionized water and dry it. Figure 3 As shown, the microscopic morphology and element distribution of PCL / nHA porous scaffolds are shown, and it is found that the three-dimensional interconnected microchannel structure inside the scaffold is clear; Step 4: prepare a biomimetic glycopeptide hydrogel solution. First, weigh methacrylylated gelatin, aldehyde-modified Bletilla striata polysaccharide and antimicrobial peptide and put them into a centrifuge tube. Add 500 μL of deionized water, vortex to completely dissolve them, then add a photoinitiator, pass nitrogen for 10-20 minutes, and obtain a uniform mixed solution after deoxygenation. Figure 1 The photo shows the biomimetic glycopeptide hydrogel solution after curing under ultraviolet light irradiation. Figure 3 As shown, this is a microscopic morphology picture of GBE hydrogel. Figure 1 The prepared GBE gel was freeze-dried and observed using a scanning electron microscope. The results showed that the hydrogel had a porous network structure inside. Step 5: Add the biomimetic glycopeptide hydrogel solution obtained in step 4 to the PCL / nHA porous scaffold treated in step 3, irradiate under ultraviolet light for free radical polymerization, obtain a PCL / nHA combined biomimetic glycopeptide hydrogel scaffold, and store it in a low-temperature sterile environment.

[0028] Specifically, the mass percentage of nHA in the ink in step 1 is between 10wt% and 30wt%.

[0029] Specifically, the diameter of the three-dimensional interconnected microchannels in the PCL / nHA implant pattern is 300 μm, and the dimensional parameters during 3D printing are: PCL / nHA porous scaffold diameter 5-7 mm, thickness 0.8-1.2 mm; molding temperature 170-185°C, preferably diameter 6 mm, thickness 1 mm, molding temperature 180°C.

[0030] Specifically, in step 4, the mass ratio of methacryloylated gelatin, aldehyded Bletilla striata polysaccharide, antimicrobial peptide and photoinitiator is 10:4:2:1, and the photoinitiator is phenyl (2,4,6-trimethylbenzoyl) lithium phosphate.

[0031] Specifically, the ultraviolet light irradiation time in step 5 is 10-20 minutes, preferably 10 minutes.

[0032] Embodiment 1: Step 1: Prepare PCL / nHA porous scaffolds. Mix PCL and nHA powders at a mass percentage of 10wt% of nHA to prepare 3D printing ink. Use Magics computer-aided design software to design a cylindrical porous PCL / nHA implant pattern with three-dimensional interconnected microchannels (diameter 300μm). Use Livprint® N series 3D printer with FDM system to print PCL / nHA porous scaffolds according to the parameters of 6mm diameter, 1mm thickness, 180℃ molding temperature, and 0.2mm nozzle diameter. After printing, take it out from the molding chamber to obtain a PCL / nHA porous scaffold with a mass of 0.09g. Step 2: Pretreatment of the PCL / nHA porous scaffold: the PCL / nHA porous scaffold prepared in step 1 was placed in a 5 mol / L sodium hydroxide solution and subjected to surface treatment at 37° C. under shaking conditions for 1 h; Step 3: Finished product treatment of the PCL / nHA porous scaffold: fully rinse the surface of the scaffold obtained in step 2 with deionized water and dry it; Step 4: prepare a biomimetic glycopeptide hydrogel solution, weigh 0.025 g of methacryloylated gelatin (G), 0.01 g of aldehyded Bletilla striata polysaccharide (B), and 0.005 g of antimicrobial peptide (E) using an analytical balance and put them into a centrifuge tube, add 500 μL of deionized water, vortex to completely dissolve them, add 0.0025 g of photoinitiator phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt, pass nitrogen for 10 minutes, and obtain a uniform mixed solution after deoxygenation; Step 5: Add the uniformly mixed solution obtained in step 4 to the scaffold of step 3, irradiate it under ultraviolet light for 10 minutes for free radical polymerization reaction, and obtain a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for skull defect replacement, which is stored in a low-temperature sterile environment.

[0033] Embodiment 2: Step 1: Preparation of PCL / nHA porous scaffold: The mass percentage of nHA in the mixture of PCL and nHA powders was adjusted to 20 wt % as 3D printing ink, and the remaining design and printing parameters were the same as in Example 1 to obtain a PCL / nHA porous scaffold.

[0034] Steps 2-5: As in Example 1, the corresponding 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold is prepared and preserved.

[0035] Embodiment 3: Step 1: Preparation of PCL / nHA porous scaffold: PCL and nHA powders were mixed at a mass percentage of 30 wt% of nHA to prepare 3D printing ink. The remaining design and printing parameters were the same as those in Example 1 to obtain a PCL / nHA porous scaffold.

[0036] Step 2-5: As in Example 1, the corresponding 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold is prepared and preserved.

[0037] Comparative Example 1: Mechanical properties test: To study the microscopic characteristics of different materials or ratios, microscopic observations were performed on samples such as 90% PCL-10% HA, 80% PCL-20% HA, 70% PCL-30% HA, Gelma, GBE, and PH@GBE. Figure 4 As shown in the figure, the microstructure images of each sample are displayed. These images can be used to compare the differences in the microstructures of different samples, providing a basis for analyzing their performance. Compression strength tests were carried out on composite materials with different proportions of PCL (polycaprolactone) and HA (hydroxyapatite), namely 100% PCL, 90% PCL-10% HA, 80% PCL-20% HA, and 70% PCL-30% HA. It can be seen from the figure that with the increase of HA content (the decrease of PCL content), the compression strength of the material shows a downward trend. The compression strength of 100% PCL is the highest, and the compression strength of 70% PCL-30% HA is the lowest. Although 100% PCL has the highest compression strength, it lacks toughness and is prone to stress concentration.

[0038] Antibacterial performance test: Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were used as experimental bacteria, and 7 experimental groups were set up, including Control, PH, B, E, G, GBE, and PH@GBE. Each experimental group was treated with two bacteria respectively, and the colony growth was observed after cultivation under appropriate conditions; Figure 5The results shown are as follows: for Staphylococcus aureus, a large number of colonies grew in the Control group, the PH group, and the G group, the number of colonies in the B group was relatively small, and there were almost no colonies in the E group, the GBE group, and the PH@GBE group. For Escherichia coli, the colonies in the Control group were distributed in a disorderly manner and in large numbers, the PH group and the G group had more colonies, the number of colonies in the B group decreased, and there were almost no colonies in the E group, the GBE group, and the PH@GBE group. By comparing the colony growth of each experimental group, it can be seen that the bactericidal effect of the E group containing antimicrobial peptides on the two bacteria was close to 100%, and the B group containing Bletilla striata polysaccharide also showed a certain antibacterial ability against the two bacteria and could inhibit bacterial growth.

[0039] Comparative Example 2: In order to comprehensively evaluate the differences between the prepared PCL / nHA@GBE scaffold and other control group materials in terms of bone marrow mesenchymal stem cells (MSCs) activity and skull repair effect, this experiment adopted the following comparison and evaluation methods: 1. CCK-8 method to determine the activity of MSCs: Control composite materials, methacryloyl gelatin, aldehyde-modified Bletilla striata polysaccharide, antimicrobial peptide, PCL / nHA, GBE and PCL / nHA@GBE were co-cultured with MSCs, and the activity of MSCs was determined using CCK-8 reagent after 1, 3 and 5 days of culture. Figure 6 As shown, the activity of bone marrow mesenchymal stem cells cultured for 1, 3, and 5 days was determined by CCK-8 method, and the cell compatibility was basically the same; 2. MSCs live and dead staining: After MSCs were treated with each group of materials for 24 hours, live and dead staining was performed, and cell survival was observed under a microscope to further verify the biocompatibility of each group of materials with MSCs. Figure 7 The figure shows the live and dead staining of bone marrow mesenchymal stem cells after 24 hours of treatment with each group of materials. The number of MSCs surviving on the surface of the scaffold using PCL / nHA@GBE is large, and the cell morphology is complete, which fully demonstrates that the scaffold has good biocompatibility and plays a positive role in the survival and growth of MSCs. 3. Analysis of rat skull CT images: Different materials were implanted into the skull defect of rats. CT images of representative rat skulls were taken 8 weeks later. The performance of each group of materials in skull repair was observed and analyzed, including the healing of bone defects, the amount of new bone formation, and the degradation of materials. Figure 8 The following are representative CT images of rat skulls 8 weeks after treatment with different materials. The CT images of rat skulls treated with PCL / nHA@GBE showed obvious induction effects and abundant calcium nodules.

[0040] In summary, the 3D printed PCL / nHA combined bionic glycopeptide hydrogel scaffold and its preparation method of the present invention, from material selection, structural design to preparation process, comprehensively solves many problems faced in the repair of infected bone defects, and has broad clinical application prospects.

[0041] It should be understood that this embodiment is only used to illustrate the present invention and is not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.

Claims

1. A 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects, characterized in that: include: 3D printed PCL / nHA porous scaffolds having three-dimensional interconnected microchannels, wherein a mixture of PCL and nHA is used as the printing material, wherein the mass percentage of nHA is 10wt%-30wt%; The biomimetic glycopeptide hydrogel layer filled in the PCL / nHA porous scaffold is prepared by mixing methacrylylated gelatin, aldehyde-modified bletilla striata polysaccharide, antimicrobial peptide and photoinitiator and polymerizing them under ultraviolet light irradiation.

2. A 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects according to claim 1, characterized in that: The dimensional parameters of the PCL / nHA porous scaffold during 3D printing are: diameter 5-7 mm, thickness 0.8-1.2 mm; molding temperature 170-185° C., and nozzle diameter 0.2 mm.

3. A 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects according to claim 1, characterized in that: The diameter of the three-dimensional interconnected microchannels of the PCL / nHA porous scaffold is 300 μm.

4. A 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects according to claim 1, characterized in that: The mass ratio of the methacryloylated gelatin, the aldehyded bletilla striata polysaccharide, the antimicrobial peptide and the photoinitiator is 10:4:2:

1.

5. A 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects according to claim 1, characterized in that: The photoinitiator is phenyl (2,4,6-trimethylbenzoyl) lithium phosphate.

6. A method for preparing a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects, characterized in that: The following steps are involved: Step 1, preparing a PCL / nHA porous scaffold, preparing a mixture of PCL and nHA powder as 3D printing ink, using computer-aided design software to design a PCL / nHA implant pattern with a three-dimensional interconnected microchannel structure, and printing the PCL / nHA porous scaffold through 3D printing technology in conjunction with an FDM system; Step 2: Pretreatment of the PCL / nHA porous scaffold: placing the PCL / nHA porous scaffold prepared in step 1 into a 5 mol / L sodium hydroxide solution and subjecting it to surface treatment at 37° C. under shaking conditions for 1-2 h; Step 3, finished product treatment of the PCL / nHA porous scaffold, rinsing the PCL / nHA porous scaffold treated in step 2 with deionized water and drying; Step 4, preparing a biomimetic glycopeptide hydrogel solution, first weighing methacrylylated gelatin, aldehyde-modified Bletilla striata polysaccharide and antimicrobial peptide into a centrifuge tube, adding 500 μL of deionized water, vortexing to completely dissolve them, adding a photoinitiator, passing nitrogen for 10-20 minutes, and obtaining a uniform mixed solution after deoxygenation; Step 5: Add the biomimetic glycopeptide hydrogel solution obtained in step 4 to the PCL / nHA porous scaffold treated in step 3, irradiate under ultraviolet light for free radical polymerization, obtain a PCL / nHA combined biomimetic glycopeptide hydrogel scaffold, and store it in a low-temperature sterile environment.

7. The method for preparing a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects according to claim 6, characterized in that: The mass percentage of nHA in the ink in step 1 is between 10wt% and 30wt%.

8. The method for preparing a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects according to claim 7, characterized in that: The diameter of the three-dimensional interconnected microchannels in the PCL / nHA implant pattern is 300 μm, and the dimensional parameters during 3D printing are: PCL / nHA porous scaffold diameter 5-7 mm, thickness 0.8-1.2 mm; molding temperature 170-185° C., nozzle diameter 0.2 mm.

9. The method for preparing a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects according to claim 6, characterized in that: In the step 4, the mass ratio of methacryloylated gelatin, aldehyded bletilla striata polysaccharide, antimicrobial peptide and photoinitiator is 10:4:2:1, and the photoinitiator is phenyl (2,4,6-trimethylbenzoyl) lithium phosphate.

10. The method for preparing a 3D printed PCL / nHA combined biomimetic glycopeptide hydrogel scaffold for replacing infected bone defects according to claim 6, characterized in that: The ultraviolet light irradiation time in step 5 is 10-20 minutes.

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