Collagen-calcium phosphate-based flexible ceramic osteochondral repair body and preparation method thereof

Abstract

The application relates to the field of biomedical materials, and particularly discloses a collagen-calcium-phosphorus-based flexible ceramic bone cartilage repair body and a preparation method thereof. The collagen-calcium-phosphorus-based flexible ceramic bone cartilage repair body comprises a calcium-phosphorus-based flexible ceramic bone phase layer, wherein beta-tricalcium phosphate ceramic microspheres and calcium phosphate powder are used as solid phase components, and distilled water or pure water, sodium hydroxide and disodium hydrogen pyrophosphate are used as liquid phase components; at least one anchoring harbor is arranged on the top surface of the bone phase layer; and a collagen porous cartilage layer is prepared by using a collagen solution and a photocuring system to prepare printing ink and then performing 3D printing. The collagen-calcium-phosphorus-based flexible ceramic bone cartilage repair body and the preparation method thereof are substantially improved in structural design, interface combination, mechanical properties, clinical operability and repair effect, and embody the integrated innovation of "flexible ceramic-collagen-anchoring structure-3D printing".

Description

Technical Field

[0001] This invention relates to the field of biomedical materials, specifically to a collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body and its preparation method. Background Technology

[0002] Currently, research on osteochondral repair materials both domestically and internationally mainly focuses on the following categories:

[0003] 1. Single calcium phosphate ceramic scaffold: Calcium phosphate ceramic materials are widely used due to their good biocompatibility and osteoconductivity, but their inherent brittleness and low bending strength result in poor fatigue performance and make it difficult to withstand the effects of complex stress environments such as joints for a long time. Therefore, they often have the risk of early failure or breakage.

[0004] 2. Single collagen or gelatin scaffolds: Collagen scaffolds, as natural polymer materials, can improve cell adhesion and tissue repair, but their mechanical properties are limited, they degrade too quickly, and their bonding force is insufficient when combined with ceramics, resulting in poor interfacial stability. In clinical practice, they are prone to delamination or detachment, leading to repair failure. Although polymer bone cement can provide some mechanical support in the short term, it is difficult to achieve long-term integration with the host bone tissue due to its lack of bioactivity and degradation characteristics.

[0005] 3. Ceramic-collagen physical composite materials: Existing technologies mostly use physical mixing or chemical cross-linking to combine ceramics and collagen. However, their interfacial bonding strength is generally insufficient (<3-5MPa), and they are prone to separation during long-term use. Furthermore, the porosity and degradation rate gradient of the material are difficult to match with the natural bone-cartilage interface.

[0006] 4. Hydrogel-ceramic or hydrogel-polymer composite systems: Some studies have proposed using hydrogels to enhance the workability of materials, but most of these studies remain at the laboratory level. They generally lack stress transmission design for ceramic particles with multi-level particle sizes and have failed to achieve effective biomimetic simulation of bone-cartilage bilayer structures.

[0007] Therefore, there is an urgent need to develop a novel osteocartilage repair material that can simultaneously meet the requirements of mechanical load-bearing capacity, bioactivity, interfacial stability, and clinical operability, in order to overcome the shortcomings of existing technologies. Summary of the Invention

[0008] The purpose of this invention is to provide a collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body and its preparation method, so as to solve the problems of insufficient mechanical properties, low interfacial bonding force and poor osteocartilage interface matching in the prior art as mentioned in the background.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body, comprising:

[0010] The calcium-phosphorus-based flexible ceramic bone phase layer uses β-tricalcium phosphate (β-TCP) ceramic microspheres and calcium dihydrogen phosphate (MCPM) powder as solid phase components, and distilled water or pure water, sodium hydroxide and disodium dihydrogen pyrophosphate as liquid phase components. The curing time is ≤30 minutes and the compressive strength is ≥10MPa. At least one anchoring port is provided on the top surface of the bone phase layer.

[0011] A porous collagen cartilage layer is formed by 3D printing using collagen solution and photocuring system to prepare printing ink. Anchor piles matching the anchorage are provided on the bottom surface of the cartilage layer, and the interface bonding strength is ≥2MPa through physical interlocking and / or printing ink bonding.

[0012] By using a composite structure of calcium phosphate-based flexible ceramic bone phase layer and collagen porous cartilage layer, "integrated bone-cartilage repair" of osteochondral defects can be achieved.

[0013] By physically interlocking the top anchoring port and the bottom anchoring pile with ink bonding, the bonding strength of the two-layer interface is ensured to be ≥2MPa, preventing delamination failure of the restoration when it is subjected to stress in the body.

[0014] The bone phase layer has a curing time of ≤30 minutes, meeting the needs of rapid clinical operation. Its compressive strength is ≥10MPa, matching the load-bearing requirements of subchondral bone. The cartilage layer is formed into a porous structure through 3D printing, which is conducive to cell ingrowth.

[0015] As a preferred embodiment of the present invention, the porosity of the bone phase layer is 10%-60%, and its degradation cycle matches the bone tissue regeneration process;

[0016] The porosity of the cartilage layer is 40%-90%, and its degradation behavior promotes chondrocyte ingrowth and differentiation.

[0017] The porosity gradient design is matched with the degradation behavior to the regeneration process, thereby improving the biomimeticity and functionality of the restoration.

[0018] As a preferred embodiment of the present invention, the porosity of the bone phase layer is achieved by adjusting the curing time, with a curing time of 7-8 minutes, corresponding to a porosity of 27%-29%.

[0019] The cartilage layer is formed by adding a 6% (w / v) collagen solution and 0.1% photosensitizer to create printing ink.

[0020] The optimal correlation between process parameters and performance, and the precise ratio of cartilage layer printing materials are defined to ensure repeatability.

[0021] As a preferred technical solution of the present invention, the ceramic microspheres in the bone phase layer adopt a multi-level particle size distribution: 50% Φ10-50μm, 20% Φ50-100μm, and 30% Φ100-200μm, to achieve multi-level stress transmission and curing time control.

[0022] Stress is transmitted in multiple stages through particle size gradient: fine particles fill the gaps, medium particles build the framework, and coarse particles bear the load, thereby improving the mechanical stability of the bone phase layer.

[0023] As a preferred embodiment of the present invention, the molar ratio of β-tricalcium phosphate to calcium dihydrogen phosphate in the bone phase layer is 0.81-1.39, the liquid / solid phase mass ratio is 0.45-0.71, and the ceramic microsphere particle size range is 10-200 μm; irregular ceramic particles can also be used, and the ratio can be selected according to specific requirements.

[0024] Precise control of the chemical equilibrium and physical dispersion of the reaction system ensures the stability of the flexible ceramic network and the uniformity of its pore structure.

[0025] As a preferred technical solution of the present invention, the anchoring pile is a spherical, arrowhead, and multi-legged claw structure with a large head and a small body, forming an embedded lock with the anchoring port, and the force difference between the three pile types is 1:(3-5):(5-10).

[0026] By enhancing the mechanical interlock of the interface through differentiated pile shape design, and combining force differences to ensure coordinated stability of different pile shapes under stress.

[0027] As a preferred technical solution of the present invention, the cartilage layer is formed by DLP photopolymerization 3D printing process with light intensity of 25mW / cm², layer thickness of 50μm, and scanning speed of 10mm / s.

[0028] By controlling the printing parameters, the accuracy and uniformity of the porous structure can be ensured.

[0029] This invention also provides a method for preparing a collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body, comprising the following steps:

[0030] Step 1: Bone phase layer construction. Ceramic microspheres and calcium dihydrogen phosphate are mixed with liquid phase in a certain proportion, injected into mold for curing, and an anchoring harbor is formed on the top surface.

[0031] Step 2: Cartilage layer construction. Collagen solution and photoinitiator are mixed to form printing ink, which is then used to form a porous structure through 3D printing and anchor piles are printed on the bottom surface.

[0032] Step 3: Assembly of the prosthesis. Before the bone layer solidifies, the cartilage layer anchor post is embedded into the anchoring port. After solidification, a prosthesis with an overall interfacial bonding strength ≥2MPa is formed.

[0033] Calcium-phosphorus-based flexible ceramics can also be directly injected into the defect site to be treated, with the cartilage layer attached before curing, and the anchoring posts of the cartilage layer embedded in the flexible ceramics to form curing fixation;

[0034] Alternatively, an anchoring bond and a porous cartilage layer can be formed on the top surface of the bone layer using 3D printing with collagen ink. The reproducibility of the prosthesis is ensured through defined process steps.

[0035] As a preferred embodiment of the present invention, the curing time in step one is 7-8 minutes, during which the porosity is stable at 27%-29%;

[0036] In step two, the collagen solution concentration of the printing ink is 6% (w / v), and the amount of photoinitiator added is 0.1%.

[0037] Clearly define the correspondence between key process parameters and performance to ensure the controllability of the method and the consistency of product performance.

[0038] As a preferred technical solution of the present invention, in step three, during assembly, the cartilage layer is printed by injecting printing ink into the anchorage and curing it, or the interface bonding is achieved by directly using the bone phase layer to cure and bond.

[0039] It offers flexible assembly process options to adapt to different clinical scenarios.

[0040] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention has achieved substantial improvements over the prior art in terms of structural design, interface bonding, mechanical properties, clinical operability and repair effect, and embodies the integrated innovation of "flexible ceramics-collagen-anchoring structure-3D printing".

[0041] 1. Differences in structural hierarchy: This invention proposes a two-layer structure system with a calcium phosphate-based flexible ceramic bone phase layer and a collagen porous cartilage layer, which achieves a gradient matching of porosity, mechanical properties and degradation rate, which is significantly different from a single material system;

[0042] 2. Difference in interfacial bonding strength: This invention achieves an interfacial bonding strength of ≥2MPa through a dual bonding mechanism of self-locking anchoring, flexible ceramics, and printing ink, which is significantly better than traditional technologies;

[0043] 3. Differences in mechanical properties and stability: This invention achieves multi-level stress transmission and improved fatigue stability through the multi-level particle size (10-200μm) ceramic microsphere gradation design, with an overall compressive strength ≥10MPa, significantly improving the load-bearing capacity;

[0044] 4. Differences in clinical operation performance: This invention optimizes the particle size of ceramic microspheres, the solid-liquid ratio of flexible ceramics, and the liquid phase formulation to achieve a curing time of ≤30 min and a process window that is injectable, formable, and operable, significantly improving the convenience of clinical operation.

[0045] 5. Differences in biological repair effects: This invention adopts a gradient porosity design of 10%-40% in the bone layer and 50%-90% in the cartilage layer, with an overall degradation cycle of about 1 year. This achieves temporal matching with the bone-cartilage regeneration process and promotes long-term stable tissue repair and functional reconstruction in the interface area. Attached Figure Description

[0046] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0047] Figure 1 This is a flowchart illustrating the preparation process of the collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body of the present invention.

[0048] Figure 2 This is a schematic diagram of the structure of the collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body of the present invention;

[0049] Figure 3 This is a scanning electron microscope image of cell adhesion in collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair tissue of the present invention.

[0050] Figure 4 This is a schematic diagram of the anchoring structure of the collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body of the present invention;

[0051] Figure 5 This is an ion release diagram of the collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body of the present invention. Detailed Implementation

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention, so that the process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0053] Please see Figures 1-5 The present invention provides the following technical solution:

[0054] A collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body includes: a calcium-phosphorus-based flexible ceramic bone phase layer, with β-tricalcium phosphate ceramic microspheres and calcium dihydrogen phosphate powder as solid phase components, and distilled water or pure water, sodium hydroxide and disodium dihydrogen pyrophosphate as liquid phase components, with a curing time ≤30 minutes and a compressive strength ≥10MPa; at least one anchoring port is provided on the top surface of the bone phase layer.

[0055] A porous collagen cartilage layer is formed by 3D printing using collagen solution and photocuring system to prepare printing ink; anchor piles matching the anchorage are provided on the bottom surface of the cartilage layer, and the interface bonding strength is ≥2MPa through physical interlocking and / or printing ink bonding.

[0056] like Figure 1 As shown, the preparation steps of collagen-calcium phosphate-based flexible ceramic osteocartilage repair body are as follows:

[0057] Step 1: Construction of calcium-phosphorus-based flexible ceramic bone phase layer:

[0058] High-purity medical-grade β-TCP ceramic microspheres (particle size 10-200μm) and MCPM powder were mixed in a ratio of 50% Φ10-50μm, 20% Φ50-100μm, and 30% Φ100-200μm, with the molar ratio of β-tricalcium phosphate to calcium dihydrogen phosphate controlled within the range of 0.81-1.39.

[0059] Distilled water or pure water is used as the solvent, sodium hydroxide (concentration 0.3mol / L) is used to adjust the pH, disodium dihydrogen pyrophosphate provides a retarding effect, and the liquid / solid mass ratio is controlled at 0.45-0.71.

[0060] Add liquid phase in proportion to form flexible ceramic, stir and mix, then quantitatively inject into a Φ3mm cylindrical silicone mold, and cure to form a Φ3mm×6mm bone phase layer, such as... Figure 2 As shown;

[0061] The mixture was stirred for 4 minutes and cured at 37°C and 95% humidity. Porosity changes were monitored in real time. The porosity changes of the bone phase layer at different curing times are as follows:

[0062]

[0063] The porosity of the bone phase layer was controlled between 10% and 60%, forming a porous structure similar to natural bone tissue. The porosity decreased with increasing reaction time; after 8 minutes, the porosity was approximately 28%, showing little statistical difference, representing the optimal curing state. The micropores of the material allowed osteoblasts to adhere tightly to the material surface via pseudopodia and grow into the pores. Figure 3 As shown, this demonstrates that the bone phase layer has good biocompatibility;

[0064] The shape of the bone phase layer can be a geometric column or an irregular shape. The size of the bone phase layer can be pre-formed according to clinical needs or injected on-site. Then, the anchoring port structure is processed. The anchoring port structure is pre-formed on the top surface of the bone phase layer using a mold. At least one self-locking anchoring structure is constructed on the top surface of the bone phase layer, and its shape and size match the anchoring pile.

[0065] The effects of different ceramic microsphere contents on the porosity of the bone phase layer (ranging from 26% to 32%) are as follows:

[0066]

[0067] As the ceramic content increases, the number of permealuminate crystals formed decreases, the number of unreacted particles increases the gaps, the amount of unreacted liquid phase increases, and the residual liquid phase causes an increase in porosity in the hardened bone phase layer.

[0068] The effects of different particle sizes on the curing time and porosity of the bone layer of ceramic microspheres are as follows:

[0069]

[0070] The ceramic microspheres of flexible ceramics have a particle size in the range of 38-150 μm, which has little effect on porosity but a significant effect on curing time.

[0071] The effects of different liquid-to-solid ratios on the porosity of the bone phase layer are as follows:

[0072]

[0073] The core function of the liquid phase is to provide a "medium for ion dissolution and diffusion". As the amount of liquid phase increases, the interparticle gaps widen, and excess liquid phase cannot participate in the reaction and is lost through volatilization, ultimately leading to a significant increase in porosity.

[0074] Step 2: Construction of a porous collagen cartilage layer:

[0075] A collagen solution with a concentration of 6% (w / v) was prepared, and 0.1% photosensitizer was added to form printing ink;

[0076] A porous collagen layer with a diameter of 3mm × 1mm and a porosity of approximately 65% ​​was prepared using DLP photopolymerization 3D printing technology with a light intensity of 25mW / cm², a layer thickness of 50μm, and a scanning speed of 10mm / s.

[0077] Three anchor piles with a Φ100μm×500μm anchoring structure were printed on the bottom surface of the collagen layer;

[0078] like Figure 4 As shown, the cartilage layer can be prefabricated into a membrane or directly printed onto the top surface of the bone layer. At least one self-locking anchor post is constructed on the bottom surface of the cartilage layer. The anchor post can be spherical, arrowhead, multi-legged, or other shapes, but is not limited to these. The bonding force of the three components is approximately in the range of 1:(3-5):(5-10). The size of the anchor post depends on the needs of the prosthesis. The porosity of the cartilage layer is controlled at 40%-90%, which is conducive to the ingrowth, proliferation, and differentiation of chondrocytes. The morphology of the cartilage layer needs to match the top surface of the bone layer and be able to integrate into one. The thickness of the cartilage layer is in the range of 0.5-5.0 mm.

[0079] Step 3: Integration and assembly of the prosthesis

[0080] By optimizing the structure and performance, the porosity and mechanical strength gradient are matched to obtain a prosthesis that is injectable, malleable and clinically operable. The molding window of the collagen-flexible ceramic composite system is determined, and the "injectable-operable-malleable" range is clarified.

[0081] Before the bone phase layer solidifies, the bottom surface of the cartilage layer is embedded on the top surface of the bone phase layer. After solidification, a complete repair is formed. The cytotoxicity evaluation (ISO 10993-5) results show no toxicity. Cell adhesion and osteogenic experiments show that the collagen layer significantly promotes cell proliferation and differentiation.

[0082] The bone layer and cartilage layer are fused together through the physical interlocking of the self-locking anchoring structure and / or the adhesive effect of the printing ink, with an interface bonding strength ≥2MPa and an overall compressive strength ≥10MPa.

[0083] Printing ink can be controlled and injected into the anchorage on the top surface of the bone layer and cured, and a cartilage layer can be directly 3D printed on its surface;

[0084] In the process of prefabrication or clinical application, the cartilage layer can be bonded together by utilizing the solidification effect of the bone phase layer. Depending on the size and depth of the patient's osteocartilage defect, one or more of these prostheses can be selected.

[0085] The microstructure, calcium-to-phosphorus ratio, and in vitro degradation behavior of the restorations were characterized by rheological, mechanical, and degradation experiments.

[0086] like Figure 5 As shown, the release of calcium, sodium, and phosphorus from the bone phase layer in liquid was analyzed using ICP detection to assess its degradation performance. Calcium atoms originated from the dissolution of percalcite and β-TCP ceramics; sodium ions originated from sodium hydroxide and disodium dihydrogen pyrophosphate in the liquid phase; and phosphorus originated from the dissolution of percalcite and β-TCP ceramics, as well as pyrophosphate ions. The release trend of these ions showed an initial increase followed by stabilization. 2+ The average daily release is 0.036%, PO4 3- It was 0.65%; at 5 days, Ca 2+ The release amount reached 21 mg / L, Na + It is 153 mg / L, PO4 3- The concentration was 292 mg / L, and the release of the three ions then tended to be constant, indicating that the bone phase layer has good degradation performance.

[0087] The collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body and its preparation method involved in this invention are suitable for repairing osteocartilage tissue defects and lesions, including large-area joint cartilage damage, meniscus replacement or repair, treatment of subchondral bone lesions, patellar cartilage repair, etc., and are widely used in medical and veterinary clinical practice.

[0088] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body, characterized in that, include: The calcium-phosphorus-based flexible ceramic bone phase layer uses β-tricalcium phosphate ceramic microspheres and calcium dihydrogen phosphate powder as solid phase components, and distilled water or pure water, sodium hydroxide and disodium dihydrogen pyrophosphate as liquid phase components. The curing time is ≤30 minutes and the compressive strength is ≥10MPa. At least one anchorage is provided on the top surface of the bone phase layer. A porous collagen cartilage layer is formed by 3D printing using collagen solution and photocuring system to prepare printing ink; anchor piles matching the anchorage are provided on the bottom surface of the cartilage layer, and the interface bonding strength is ≥2MPa through physical interlocking and / or printing ink bonding. The anchoring piles are spherical, arrowhead, and multi-legged claw structures with large heads and small bodies, forming an embedded lock with the anchoring port. The force difference between the three pile types is 1:(3-5):(5-10).

2. The collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body according to claim 1, characterized in that: The porosity of the bone phase layer is 10%-60%, and its degradation cycle matches the bone tissue regeneration process. The porosity of the cartilage layer is 40%-90%, and its degradation behavior promotes chondrocyte ingrowth and differentiation.

3. The collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body according to claim 2, characterized in that: The porosity of the bone phase layer is achieved by adjusting the curing time, which is 7-8 minutes, corresponding to a porosity of 27%-29%. The cartilage layer is formed by adding a 6% (w / v) collagen solution and 0.1% photosensitizer to form printing ink.

4. The collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body according to claim 1, characterized in that: The ceramic microspheres in the bone phase layer adopt a multi-level particle size distribution: 50% Φ10-50μm, 20% Φ50-100μm, and 30% Φ100-200μm, to achieve multi-level stress transmission and curing time control.

5. The collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body according to claim 4, characterized in that: The molar ratio of β-tricalcium phosphate to calcium dihydrogen phosphate in the bone phase layer is 0.81-1.39, the liquid / solid mass ratio is 0.45-0.71, and the ceramic microsphere particle size ranges from 10 to 200 μm.

6. The collagen-calcium-phosphorus-based flexible ceramic osteocartilage repair body according to claim 1, characterized in that: The cartilage layer was formed by DLP photopolymerization 3D printing process with a light intensity of 25mW / cm², a layer thickness of 50μm, and a scanning speed of 10mm / s.

7. A method for preparing a collagen-calcium phosphate-based flexible ceramic osteocartilage prosthesis according to any one of claims 1-6, characterized in that: The preparation method includes the following steps: Step 1: Bone phase layer construction. Ceramic microspheres and calcium dihydrogen phosphate are mixed with liquid phase in a certain proportion, injected into mold for curing, and an anchoring harbor is formed on the top surface. Step 2: Cartilage layer construction. Collagen solution and photoinitiator are mixed to form printing ink, which is then used to form a porous structure through 3D printing and anchor piles are printed on the bottom surface. Step 3: Assembly of the prosthesis. Before the bone layer solidifies, the cartilage layer anchor post is embedded into the anchoring port. After solidification, a prosthesis with an overall interfacial bonding strength ≥2MPa is formed.

8. The method for preparing a collagen-calcium-phosphorus-based flexible ceramic osteocartilage prosthesis according to claim 7, characterized in that: In step three, during assembly, the cartilage layer is printed by injecting printing ink into the anchorage and curing it, or by directly using the bone phase layer to cure and bond the interface.

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