Artificial bone compact block scaffold material and preparation method thereof

Abstract

The invention discloses an artificial bone compact block scaffold material, the artificial bone compact block scaffold material is a block solid structure formed by pressing mixture slurry, the mixture comprises, by mass, 80-90% of mineralized collagen fiber and 10-20% of a water-soluble polymer material, and the sum of the mass percentages of the above components is 100%. The invention also discloses a preparation method of the artificial bone dense block scaffold material, and the required artificial bone dense block scaffold material is obtained by mixing the mineralized collagen fibers prepared by independent research and development with a water-soluble polymer material as a cross-linking agent, heating and stirring, and then carrying out injection molding and pressing. The material provided by the invention is convenient to use, and the pressed and molded blocky solid has the characteristics of higher toughness, convenience in secondary processing and wider clinical application compared with the original biomimetic material.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomaterials, and in particular relates to an artificial bone dense block scaffold material. The present invention also relates to a method for preparing the material. Background Art

[0002] Bionic bone materials are a growing trend in bone implant materials due to their ability to mimic the composition and structure of natural bone and their suitable degradation properties. Bionic mineralized collagen fiber artificial bone repair materials, with their collagen / nanohydroxyapatite composite composition and micro-nano hierarchical structure, are highly similar to natural human bone. Implantation into bone defects can induce new bone regeneration and accelerate bone healing, making them a promising biomaterial.

[0003] In existing technologies, mineralized collagen fibers can be prepared through in situ co-assembly. These mineralized collagen fibers typically exist in the form of micro-nanoscale powders. Using them alone makes it difficult to meet mechanical support requirements. Their lack of toughness also results in fragile, easily broken blocks after molding. Therefore, they are typically combined with synthetic polyester materials to maximize the benefits of mineralized collagen. However, when traditional cross-linked materials are combined with mineralized collagen fibers, the amount of nanofibers introduced into the polymer is very limited, typically not exceeding 50%. Furthermore, these polymers degrade during application to form acidic substances, which can lead to unpredictable disintegration, thus compromising bone repair and mechanical support.

[0004] With the development of medical technology, the original polyester composite materials are unable to meet the preparation requirements of special surgical instruments and realize the bionic manufacturing of multi-dimensional high-performance bone structure materials. Therefore, the development of a new generation of functional bionic mineralized collagen-based bone defect regeneration and repair materials has great scientific significance and clinical application value. Summary of the Invention

[0005] The purpose of the present invention is to provide an artificial bone dense block scaffold material, which uses independently developed biomimetic mineralized collagen fibers as the main material. After pressing, it has stronger toughness than the original biomimetic material, is easy to be processed into any desired shape through injection molding, hot pressing, etc., and has a wider range of clinical applications.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned material.

[0007] The technical solution adopted by the present invention is that the artificial bone dense block scaffold material is a block solid structure formed by pressing a mixture slurry. The mixture includes 80-90% mineralized collagen fibers and 10-20% water-soluble polymer materials by mass percentage, and the sum of the mass percentages of the above components is 100%.

[0008] The present invention is also characterized in that:

[0009] The mineralized collagen fibers are composed of collagen fibers and hydroxyapatite crystals, and the mass percentage of the collagen fibers in the mineralized collagen fibers is no more than 20%.

[0010] The mineralized collagen fibers are mineralized collagen fibers doped with active elements, and the active elements include any one or more of silicon, selenium, magnesium, zinc, strontium, silver, iron and copper;

[0011] The average length of mineralized collagen fibers is 250 nm to 300 nm;

[0012] The average diameter of mineralized collagen fibers is 6 nm to 9 nm.

[0013] The water-soluble polymer material is one of polyvinyl alcohol, polyethylene glycol and polyethylene oxide.

[0014] Artificial bone dense block scaffold materials are used for the preparation of bone repair surgical instruments, including intervertebral fusion devices, skull plugs and skull locks.

[0015] Another technical solution adopted by the present invention is a method for preparing the above-mentioned material, which is specifically carried out according to the following steps:

[0016] S1: Preparation of mineralized collagen fibers using in situ co-assembly method;

[0017] S2: Weigh 5-10 g of mineralized collagen fibers and 1-2 g of water-soluble polymer material;

[0018] S3: Add deionized water to the water-soluble polymer material in S2 and stir under heating until the solution is clear;

[0019] S4: mixing the mineralized collagen fibers in S2 with the solution in S3 to obtain a mixture slurry;

[0020] S5: The mixture slurry in S4 is subjected to injection molding and pressing treatment to prepare an artificial bone dense block scaffold material.

[0021] The water-soluble polymer material in S2 is one of polyvinyl alcohol, polyethylene glycol, and polyethylene oxide.

[0022] Add 10-15 ml of deionized water to S3, heat to 90-95 degrees Celsius, and stir for 2-4 hours.

[0023] The mixing and stirring time in S4 is 12-36 hours.

[0024] The pressure parameter during pressing in S5 is 500-1500MPa.

[0025] The beneficial effects of the present invention are as follows: the artificial bone dense block scaffold material, through the combination of independently developed mineralized collagen fibers and water-soluble polymer materials, forms a bionic material with ultra-high mineral content, excellent mechanical properties, and good biological properties. The solid block structure formed after pressing has high toughness on the basis of ensuring mechanical properties, which is convenient for secondary processing plasticity and can be used for the manufacture of special surgical instruments including intervertebral fusion devices, skull plugs, skull locks, etc. Its high mineral content is almost the same as that of biological bones, which is completely close to the real bone structure, avoiding stress shielding and affecting bone development. On the other hand, the fluidity of the mixture slurry can be used to pressure-form block structures of various complex shapes, which is convenient for adopting the "injection molding-pressurization" process to realize high-performance block bone repair scaffolds that match different defect shapes; the mixture can be made into powder for easy storage and transportation, on-site processing, and better shape matching. Compared with existing materials, the material of the present invention does not need to be heated during processing, and can be formed at room temperature to realize the construction of block materials, which has a wider range of application conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a SEM microscopic morphology of the mixture powder of the present invention;

[0027] Figure 2 This is a TEM microscopic morphology image of the mixture slurry in the present invention;

[0028] Figure 3 This is a thermogravimetric analysis diagram of the mineralized collagen fiber and artificial dense bone block scaffold material of the present invention;

[0029] Figure 4 This is a Fourier transform infrared spectrum test chart of the artificial bone dense block scaffold material of the present invention;

[0030] Figure 5 is the XRD pattern of the artificial dense bone block scaffold material of the present invention;

[0031] Figure 6 This is a graph showing the mechanical properties of the artificial dense bone block scaffold material of the present invention;

[0032] Figure 7 This is a live / dead staining and cell morphology image of the artificial dense bone block scaffold material of the present invention;

[0033] Figure 8 This is an experimental diagram showing the use of the artificial dense bone block scaffold material of the present invention for repairing long bone defects in rats;

[0034] Figure 9 is a graph of the second derivative of the phosphate peak under different pressure conditions in the present invention;

[0035] Figure 10This is a microscopic morphology of PCL / mineralized collagen fibers after freeze-drying in Comparative Example 1;

[0036] Figure 11 This is a comparison chart of the molding effects of the artificial dense bone block scaffold material in the present invention, the mineralized collagen fiber / PCL in Comparative Example 1, and the pure mineralized collagen fiber in Comparative Example 2. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] The artificial bone dense block scaffold material provided by the present invention is a block solid structure formed by pressing a mixture slurry. The mixture includes 80-90% of mineralized collagen fibers and 10-20% of water-soluble polymer materials in mass percentage, and the sum of the mass percentages of the above components is 100%. The formation of the solid structure does not rely on the adhesive effect of the water-soluble polymer material. The above-mentioned water-soluble non-polar polymer material only plays an auxiliary connecting role and is not the main body of the cross-linking agent. The pressure fusion process mainly relies on tissue transformation under pressure. The surface of the mineralized collagen fiber has a low crystalline crystal structure. During the pressure fusion process, a stable block structure is achieved through the fusion between crystals.

[0039] In order to facilitate storage and transportation, the mixture of mineralized collagen fibers and water-soluble polymer materials can be processed by centrifugal dehydration and freeze-drying to be made into powder for storage, and then mixed with water for the second time during molding. Figure 1 and Figure 2 The microstructures of the mixed powder and slurry are shown respectively.

[0040] Mineralized collagen fibers are composed of collagen fibers and hydroxyapatite crystals. The water-soluble polymer material can be one of polyvinyl alcohol, polyethylene glycol, and polyethylene oxide. The introduction of a small amount of polymer material ensures material strength and increases overall toughness after molding. The mass percentage of collagen fibers in the mineralized collagen fibers does not exceed 20%.

[0041] Among them, the mineralized collagen fibers can be mineralized collagen fibers doped with active elements, and the active elements include any one or more of silicon, selenium, magnesium, zinc, strontium, silver, iron and copper. The introduction of active elements can enhance the biological properties of the material and induce the regeneration of defective bones.

[0042] The average length of the mineralized collagen fibers is 250 nm to 300 nm; the average diameter of the mineralized collagen fibers is 6 nm to 9 nm.

[0043] The mineral content of the solid block of artificial bone dense block scaffold material after molding can reach up to 70.9%, which is higher than the mineral content in bovine bones. The mineralized collagen fibers doped with active elements make the artificial bone dense block material closer to the composition of real bones, reducing the rejection reaction. Therefore, it is suitable for the preparation of special surgical instruments in bone repair surgery, such as intervertebral fusion devices, skull plugs and skull locks.

[0044] The preparation method of the artificial bone dense block scaffold material of the present invention is specifically implemented according to the following steps:

[0045] S1: Prepare a certain amount of mineralized collagen fibers using the in situ co-assembly method;

[0046] The in situ co-assembly method in S1 specifically includes the following steps:

[0047] S101: mixing type I collagen sponge with a phosphoric acid solution to completely dissolve the type I collagen sponge, thereby obtaining a collagen template solution for later use;

[0048] S102: preparing a calcium salt solution, wherein the volume of the calcium salt solution is the same as the volume of the collagen template solution;

[0049] S103: preparing a buffer solution, wherein the buffer solution is selected from any one or more of Tris-HCl and phosphate buffer solution;

[0050] S104: titrating the collagen template solution and the calcium salt solution in a buffer solution to obtain a mixed solution; during the titration, the pH value of the mixed solution is maintained between 8 and 10;

[0051] S105: The mixed solution in S104 is subjected to high-speed centrifugation, and the supernatant obtained by centrifugation is replaced with an equal volume of ultrapure water until the pH of the supernatant is measured to be about 7 to 8, and then the high-speed centrifugation is stopped;

[0052] S106: removing moisture from the precipitate obtained in S105 to obtain mineralized collagen fibers.

[0053] In the above steps, the active element can be incorporated as an anion in S101 by first mixing a salt containing anions with a phosphoric acid solution until completely dissolved, and then mixing it with the type I collagen sponge. Alternatively, in S102, the active element can be incorporated as a cation by first mixing a salt containing cations with a calcium salt solution until completely dissolved, and then mixing it with the collagen template solution. The incorporation of the active element makes the biomimetic material more similar to the composition of natural bone, enhancing its osteoinductive capacity and enabling multiple biological functions.

[0054] S2: Weigh 5-10 g of mineralized collagen fibers and 1-2 g of a water-soluble polymer material according to mass percentage; the water-soluble polymer material is one of polyvinyl alcohol, polyethylene glycol, and polyethylene oxide;

[0055] S3: Add 10-15 ml of deionized water to the water-soluble polymer material in S2 and stir under heating until the solution becomes clear; the heating temperature is 90-95 degrees Celsius and the stirring time is 2-4 hours;

[0056] S4: mixing the mineralized collagen fibers in S2 with the solution in S3 for 12-36 hours to obtain a mixture slurry;

[0057] S5: injection molding and pressing the mixture slurry described in S4 at a pressure of 500-1500 MPa to prepare an artificial bone dense block scaffold material.

[0058] The mixture has good fluidity in the slurry state and will not precipitate in a short time; it is more conducive to injection molding, wherein the content of mineralized collagen fibers is 87%, and after injection molding and compression molding, it has a block structure.

[0059] like Figure 3 As shown, TGA testing of the artificial dense bone block scaffold material and mineralized collagen fibers of the present invention revealed the following results: the mineral content of the mineralized collagen fibers was 81.5%, while the mineral content of the block structure was 70.9%, which is the same as the mineral content of natural bone structure. The calculated incorporation of mineralized collagen fibers reached 87%.

[0060] like Figure 4 As shown, the artificial dense bone block scaffold material of the present invention is subjected to Fourier transform infrared spectroscopy test, which shows that it has a characteristic peak structure of phosphoric acid.

[0061] Figure 5 Shown is the XRD pattern of the artificial dense bone block scaffold material. The pressed block structure has the same crystal structure as the natural bone structure.

[0062] Figure 6 This graph shows the mechanical properties of artificial bone block scaffold materials. The pressed block structure exhibits excellent strength, toughness, and hardness. The absence of cracks at the indentation boundary indicates the material's excellent toughness.

[0063] Figure 7 The live / dead staining and cell morphology of the artificial bone dense block scaffold material are shown, and it can be seen that the material has good cell compatibility and has a good repair effect during implantation in the body.

[0064] like Figure 8As shown in the figure, the artificial dense bone block scaffold material was used in the long bone defect repair experiment in rats, and it can be seen that it has good in vivo support and tissue compatibility.

[0065] Figure 9 The second derivative curves of the phosphate peak under different pressure conditions show that the increase in pressure leads to a higher proportion of mature crystal structure peaks, which causes a certain phase transformation of the crystal under pressure and increases the fusion of the bulk structure.

[0066] Example 1

[0067] The method for preparing the artificial bone dense block scaffold material provided in this embodiment 1 includes the following steps:

[0068] S1: Preparation of mineralized collagen fibers using in situ co-assembly method;

[0069] S2: Weigh 10 g of mineralized collagen fibers and 1.5 g of polyvinyl alcohol;

[0070] S3: Add 15 ml of deionized water to the polyvinyl alcohol in S2 and stir at 90 degrees Celsius for 4 hours until the solution becomes clear;

[0071] S4: The mineralized collagen fibers of S2 and the polyvinyl alcohol solution of S3 were mixed and stirred for 12 h to obtain a mixture slurry;

[0072] S5: The mixture slurry described in S4 is injection molded and pressed under a pressure of 1000 MPa to prepare an artificial bone dense block scaffold material.

[0073] The artificial bone dense block scaffold material prepared in Example 1 has a mineralized collagen fiber content of 87%, an average length of the mineralized collagen fibers of 250 nm, and an average diameter of the mineralized collagen fibers of 7 nm.

[0074] Example 2

[0075] The method for preparing the artificial bone dense block scaffold material provided in this embodiment 2 includes the following steps:

[0076] S1: Preparation of mineralized collagen fibers using in situ co-assembly method;

[0077] S2: Weigh 5 g of mineralized collagen fibers and 1 g of polyethylene glycol;

[0078] S3: Add 10 ml of deionized water to the polyvinyl alcohol in S2 and stir at 95 degrees Celsius for 2 hours until the solution becomes clear;

[0079] S4: The mineralized collagen fibers of S2 and the polyvinyl alcohol solution of S3 were mixed and stirred for 36 hours to obtain a mixture slurry;

[0080] S5: The mixture slurry described in S4 is injection molded and pressed under a pressure of 1500 MPa to obtain an artificial bone dense block scaffold material.

[0081] The dense block scaffold material for bone preparation prepared in Example 2 has a mineralized collagen fiber content of 83%, an average length of the mineralized collagen fibers of 300 nm, and an average diameter of the mineralized collagen fibers of 6 nm.

[0082] Example 3

[0083] The method for preparing the artificial bone dense block scaffold material provided in Example 3 includes the following steps:

[0084] S1: Preparation of mineralized collagen fibers using in situ co-assembly method;

[0085] S2: Weigh 8 g of mineralized collagen fibers and 2 g of polyethylene oxide;

[0086] S3: Add 12 ml of deionized water to the polyvinyl alcohol in S2 and stir at 93 degrees Celsius for 3 hours until the solution becomes clear;

[0087] S4: The mineralized collagen fibers of S2 and the polyvinyl alcohol solution of S3 were mixed and stirred for 24 hours to obtain a mixture slurry;

[0088] S5: The mixture slurry described in S4 is injection molded and pressed at a pressure of 500 MPa to prepare an artificial bone dense block scaffold material.

[0089] The dense block scaffold material of the bone prepared in Example 3 has a mineralized collagen fiber content of 80%, an average length of the mineralized collagen fibers of 270 nm, and an average diameter of the mineralized collagen fibers of 9 nm.

[0090] Comparative Example 1

[0091] The difference between Comparative Example 1 and Example 3 of the present invention is that S2 uses polycaprolactone (PCL) instead of the original water-soluble polymer material, and S3 adds C4H8O2 (1,4-dioxane) solution to polycaprolactone. The steps are the same as those in Example 3. Figure 10 The figure shows the microscopic morphology of PCL / mineralized collagen fibers after freeze-drying. Because PCL is insoluble in water and has limited solubility in organic solvents, although the final material can be formed, the mineralized collagen fiber content is only 40%, presenting a loose and porous block. The mixture slurry also cannot have sufficient fluidity, and the volatilization of organic solvents will lead to environmental pollution and other problems.

[0092] Comparative Example 2

[0093] The difference between Comparative Example 2 and Example 3 of the present invention is that the mineralized collagen fibers prepared in S1 are not compounded with polyester materials, but are directly subjected to injection molding and pressing by S5. Although the molding can still be performed, the block structure formed by the pure mineralized collagen fibers does not have toughness, and the block is brittle and easily broken, making it difficult to process. Figure 11 As shown, from left to right are the block structures of mineralized collagen fibers / PVA, mineralized collagen fibers / PCL, and pure mineralized collagen fibers after pressing. The fiber blocks that are not compounded with polyester materials are broken.

[0094] The artificial bone dense block scaffold material provided by the present invention utilizes independently developed mineralized collagen fibers as the main body. The mineralized collagen fibers have a low-crystalline crystal structure on the fiber surface. Under the action of pressure, crystal fusion can occur to achieve a stable crystal structure, so that the formed block solid has an ultra-high mineral content and sufficient mechanical support. A small amount of water-soluble polymer materials such as polyvinyl alcohol are further added as auxiliary cross-linking agents, which overcomes the problem of insufficient mineral introduction during use of traditional cross-linking materials, while ensuring the strength and stiffness of the material, while enhancing the toughness of the solid after molding, avoiding the problem of fragmentation of the formed block. By regulating the ratio of mineralized collagen fibers to water-soluble polymer materials, the mineral content in the molded block can be flexibly controlled to make it close to the real bone structure and maintain good biological activity, which has wide application value in clinical practice.

Claims

1. Artificial bone dense block scaffold material, characterized in that: The artificial bone dense block scaffold material is a block solid structure formed by pressing a mixture slurry. The mixture comprises 80-90% mineralized collagen fibers and 10-20% water-soluble polymer materials by mass percentage, and the sum of the mass percentages of the above components is 100%.

2. The artificial bone dense block scaffold material according to claim 1, characterized in that: The mineralized collagen fibers are composed of collagen fibers and hydroxyapatite crystals, and the mass percentage of the collagen fibers in the mineralized collagen fibers is no more than 20%.

3. The artificial bone dense block scaffold material according to claim 2, characterized in that: The mineralized collagen fibers are mineralized collagen fibers doped with active elements, and the active elements include any one or more of silicon, selenium, magnesium, zinc, strontium, silver, iron and copper; The average length of the mineralized collagen fibers is 250 nm to 300 nm; The average diameter of the mineralized collagen fibers is 6 nm to 9 nm.

4. The artificial bone dense block scaffold material according to claim 1, characterized in that: The water-soluble polymer material is one of polyvinyl alcohol, polyethylene glycol and polyethylene oxide.

5. The artificial bone dense block scaffold material according to claim 1, characterized in that: The artificial bone dense block scaffold material is used for preparing bone repair surgical instruments, which include intervertebral fusion devices, skull plugs and skull locks.

6. The method for preparing the artificial bone dense block scaffold material according to any one of claims 1 to 5, characterized in that: The steps include: S1: Preparation of mineralized collagen fibers using in situ co-assembly method; S2: Weigh 5-10 g of mineralized collagen fibers and 1-2 g of water-soluble polymer material; S3: adding deionized water to the water-soluble polymer material in S2, and stirring under heating until the solution is clear; S4: mixing the mineralized collagen fibers in S2 with the solution in S3 to obtain a mixture slurry; S5: The mixture slurry described in S4 is subjected to injection molding and pressing treatment to prepare an artificial bone dense block scaffold material.

7. The method for preparing the artificial bone dense block scaffold material according to claim 6, characterized in that: The water-soluble polymer material in S2 is one of polyvinyl alcohol, polyethylene glycol, and polyethylene oxide.

8. The method for preparing the artificial bone dense block scaffold material according to claim 6, characterized in that: Add 10-15 ml of deionized water to S3, heat to 90-95 degrees Celsius, and stir for 2-4 hours.

9. The method for preparing the artificial bone dense block scaffold material according to claim 6, characterized in that: The mixing and stirring time in S4 is 12-36 hours.

10. The method for preparing the artificial bone dense block scaffold material according to claim 6, characterized in that: The pressure parameter during pressing in S5 is 500-1500MPa.

Images