Injectable high-strength calcium phosphate-based bone cement as well as preparation method and application thereof

Abstract

The invention discloses injectable high-strength calcium phosphate-based bone cement as well as a preparation method and application thereof, and belongs to the field of biomedical materials. The calcium phosphate-based bone cement is prepared from solid-phase powder and curing liquid, the solid powder comprises brushite powder formed by mixing beta-tricalcium phosphate and anhydrous monocalcium phosphate, and a carbon nano tube; the curing liquid at least comprises an aqueous solution of citric acid, hydroxypropyl methyl cellulose and polyethylene glycol; the bone cement is prepared by blending a curing liquid and solid-phase powder according to a ratio of 0.4-0.6 g / g. The bone cement prepared by the invention has excellent operation performance, collapse resistance and biocompatibility, is easy to inject and high in mechanical strength, can induce apatite deposition, and shows good bone induction capability. Therefore, the bone cement is suitable for the field of dental and orthopedic filling repair.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials technology, specifically relating to an injectable high-strength calcium phosphate-based bone cement, its preparation method, and its application. Background Technology

[0002] Repairing bone defects caused by trauma, tumors, infections, and osteoporosis is a major clinical challenge, especially the repair and regeneration of large bone defects. Filling with bone repair materials is currently a common approach. Polymethyl methacrylate (PMMA) bone cement and calcium phosphate (CPC) bone cement are the most commonly used self-curing bone repair materials in clinical practice. PMMA bone cement has high mechanical strength and provides excellent mechanical support after implantation. However, its excessive heat release, poor biodegradability, and poor biocompatibility limit its further application. CPC, due to its good self-curing ability and biocompatibility, is widely used in orthopedics and dentistry.

[0003] β-Tricalcium phosphate (β-TCP), as a promising CPC bone cement material, can effectively promote bone tissue repair and regeneration, and it can self-cure, possessing certain mechanical properties, making it an ideal alternative to autologous and allogeneic bone. β-TCP reacts with calcium dihydrogen phosphate under aqueous conditions to form permealuminate phosphate, thus solidifying. However, the poor mechanical properties of permealuminate phosphate bone cement limit its application in weight-bearing bone defect repair surgery; its low mechanical strength means the bone cement cannot withstand normal physiological loads, deforming or fracturing under stress, failing to provide sufficient support for new bone growth, leading to delayed fracture healing or nonunion.

[0004] Carbon nanotubes possess excellent mechanical strength, making them ideal for improving the mechanical properties of calcium phosphate-based materials. The nanoscale characteristics of carbon nanotubes allow them to form a reinforcing phase within the bone cement matrix and improve its microstructure, thereby enhancing mechanical strength. However, while carbon nanotubes can improve the mechanical properties of bone cement, the improvement is limited. Furthermore, the introduction of carbon nanotubes can adsorb water molecules, leading to increased water demand in the bone cement and resulting in uneven solid-liquid mixing, which negatively impacts its performance. In addition, excessively rapid curing speed, poor workability, and inability to be injected are bottlenecks in the clinical use of permeable phosphate rock bone cement. The introduction of carbon nanotubes into bone cement can form heterogeneous nucleation sites, accelerating the nucleation and growth of hydration products. Therefore, carbon nanotubes can further contribute to problems such as difficulty in injection and inability to mix permeable phosphate rock bone cement.

[0005] To address the issues of rapid curing speed and poor injectability and anti-collapse properties of calcium phosphate-based bone cement, researchers have proposed various strategies, primarily by adding organic polymers such as sodium alginate, chitosan, and cellulose to improve the rheological properties of the bone cement, thereby endowing it with good injectability and workability. For example, CN105327395A discloses a method for preparing acidic hydroxyapatite-catalyzed cured bone cement. By introducing citric acid-modified hydroxyapatite, acidified chitosan, hydroxypropyl methylcellulose, and gelatin, the curing time of the calcium phosphate bone cement is extended, and its compressive strength is improved. However, the bone cement obtained by this method has a maximum curing time of approximately 80 seconds and a maximum compressive strength of approximately 9 MPa, indicating that the curing time is still relatively short and the mechanical properties are low. CN1919357A discloses a premixed paste-like calcium phosphate bone cement. By introducing polyethylene glycol as the liquid phase, a premixed, ready-to-use bone cement paste is formed. The polyethylene glycol, as a non-aqueous liquid phase, provides a protective medium for long-term storage. The paste's curing primarily relies on the exchange of water from the tissue fluid with the cement, resulting in gradual hardening. However, this bone cement suffers from insufficient curing reaction and slow development of mechanical strength. Furthermore, a single organic polymer is insufficient to achieve a synergistic improvement in anti-collapse properties, injectability, curing characteristics, and mechanical properties. Therefore, there is an urgent need to develop an injectable, anti-collapse type calcium phosphate bone cement with good self-curing properties. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to address the shortcomings of existing technologies by providing an injectable high-strength calcium phosphate-based bone cement, its preparation method, and its application.

[0007] The bone cement prepared by this invention can solve the problems of insufficient injection performance, poor anti-collapse properties and excessively fast curing speed of existing calcium phosphate-based materials, and obtain a calcium phosphate-based bone cement material with high osteogenic activity.

[0008] Technical solution: The objective of this invention is achieved through the following technical solution:

[0009] The present invention provides an injectable high-strength calcium phosphate-based bone cement, wherein the bone cement is prepared by a solid phase powder and a curing liquid; the solid phase powder comprises calcium phosphate powder and carbon nanotubes, which are composed of a mixture of β-tricalcium phosphate and anhydrous calcium dihydrogen phosphate; the curing liquid comprises at least an aqueous solution of citric acid, hydroxypropyl methylcellulose and polyethylene glycol.

[0010] This invention utilizes carbon nanotubes in conjunction with citric acid, hydroxypropyl methylcellulose, and polyethylene glycol to form an organic-inorganic composite material. Carbon nanotubes enhance the mechanical properties of calcium phosphate-based materials and impart better osteoinductive properties. Meanwhile, citric acid and polyethylene glycol prolong the curing time of bone cement, and hydroxypropyl methylcellulose strengthens the cohesion and anti-collapse properties of bone cement particles, giving the material good biocompatibility and osteoinductive properties.

[0011] Preferably, the bone cement is prepared by mixing a curing liquid and a solid powder at a ratio of 0.4 to 0.6 g / g.

[0012] Preferably, in the solid powder, the weight percentage of permealuminate powder is 98-99.5%, the weight percentage of carbon nanotubes is 0.5-2%, and the sum of the weight percentages of the two is 100%.

[0013] Preferably, in the calcium phosphate powder, the weight percentage of β-tricalcium phosphate is 55-65%, and the weight percentage of anhydrous calcium dihydrogen phosphate is 35-45%.

[0014] Preferably, the curing liquid is an aqueous solution containing citric acid, hydroxypropyl methylcellulose and polyethylene glycol.

[0015] More preferably, in the curing liquid, the weight percentage of citric acid is 15-25%, the weight percentage of hydroxypropyl methylcellulose is 1-3%, the weight percentage of polyethylene glycol is 5-15%, and the balance is water.

[0016] The present invention also provides a method for preparing the above-mentioned injectable high-strength calcium phosphate-based bone cement, comprising the following steps:

[0017] (1) β-tricalcium phosphate, anhydrous calcium dihydrogen phosphate and carbon nanotubes were uniformly mixed to obtain a solid powder.

[0018] (2) Add citric acid, hydroxypropyl methylcellulose and polyethylene glycol to water and dissolve them completely to obtain a homogeneous liquid phase and a curing liquid;

[0019] (3) Mix the solid powder and curing liquid in a uniform ratio to obtain the injectable high-strength calcium phosphate-based bone cement.

[0020] This invention also provides the application of the aforementioned injectable high-strength calcium phosphate-based bone cement in dental and orthopedic filling and restorative materials. The injectable high-strength calcium phosphate-based bone cement provided by this invention can be applied in biomedical fields such as bone injury treatment.

[0021] Beneficial effects:

[0022] 1. This invention combines carbon nanotubes with citric acid, hydroxypropyl methylcellulose, and polyethylene glycol to form an organic-inorganic composite material. The carbon nanotubes enhance the mechanical properties of the calcium phosphate-based material and give it better osteoinductive properties. At the same time, the hydroxypropyl methylcellulose strengthens the cohesion of bone cement particles, while the citric acid and polyethylene glycol prolong the setting time, improving the workability and anti-collapse properties of the bone cement. This gives the material good biocompatibility and osteoinductive properties.

[0023] 2. The calcium phosphate-based bone cement of this invention has excellent apatite mineralization ability, which can promote the deposition of apatite crystals and enhance the mineralization ability of osteoblasts.

[0024] 3. This invention obtains injectable high-strength calcium phosphate-based bone cement material by adjusting the ratio of solid powder to curing liquid to meet clinical needs. Attached Figure Description

[0025] Figure 1 The static anti-collapse performance test diagrams are of the calcium phosphate bone cement prepared in Examples 1-3, Example 6 and Comparative Example 1 of this invention.

[0026] Figure 2 The static anti-collapse performance test diagrams are shown for the calcium phosphate bone cement prepared in Example 1 and Comparative Examples 4 and 5 of this invention.

[0027] Figure 3 The curing time diagrams are shown for the calcium phosphate bone cement prepared in Examples 1-5 and Comparative Examples 1 and 2 of this invention.

[0028] Figure 4 These are photographs of the calcium phosphate bone cement prepared in Comparative Examples 2 and 3 of this invention after mixing.

[0029] Figure 5 Injection diagrams of calcium phosphate bone cement prepared in Examples 6 and 7 and Comparative Examples 4 and 5 of the present invention;

[0030] Figure 6 The compressive strength diagrams are for the calcium phosphate bone cement prepared in Examples 1-3 and Comparative Example 1 of this invention.

[0031] Figure 7 The XRD patterns of the hydration products of calcium phosphate bone cement prepared in Example 3 and Comparative Example 1 of this invention are shown.

[0032] Figure 8 This is a SEM image of the apatite deposition on the surface of calcium phosphate bone cement prepared in Example 3 of the present invention.

[0033] Figure 9 The XRD patterns of surface mineralization of calcium phosphate bone cement prepared in Examples 1-3 and Comparative Example 1 of this invention are shown.

[0034] Figure 10 Cell activity diagrams of calcium phosphate bone cement prepared in Examples 1-3 and Comparative Example 1 of this invention;

[0035] Figure 11 Alizarin Red (ARS) staining images of calcium phosphate bone cement prepared in Examples 1-3 and Comparative Example 1 of this invention;

[0036] Figure 12Alkaline phosphatase (ALP) staining images of calcium phosphate bone cement prepared in Examples 1 and 2 and Comparative Example 1 of this invention. Detailed Implementation

[0037] The technical solution of the present invention will be described in detail below through specific embodiments, but the scope of protection of the present invention is not limited to the embodiments described.

[0038] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0039] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the experimental materials used in the following examples are commercially available products.

[0040] In the embodiments and comparative examples of this invention, the polyethylene glycol is liquid polyethylene glycol 400, and the carbon nanotubes are carbon nanofiber powders with a diameter of 50-300 nm, a length of 5-15 μm, a purity greater than 99.9%, and a specific surface area of ​​15-30 m². 2 / g, purchased from Jiacai Technology Co., Ltd.

[0041] Example 1

[0042] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0043] (2) Mix 99.5% calcium phosphate powder and 0.5% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0044] (3) Dissolve 20% citric acid, 2% hydroxypropyl methylcellulose and 10% polyethylene glycol 400 in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid.

[0045] (4) The above-mentioned curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0046] Example 2

[0047] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0048] (2) Mix 99% calcium phosphate powder and 1% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0049] (3) Dissolve 20% citric acid, 2% hydroxypropyl methylcellulose and 10% polyethylene glycol 400 in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid.

[0050] (4) The above-mentioned curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0051] Example 3

[0052] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0053] (2) Mix 98% calcium phosphate powder and 2% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0054] (3) Dissolve 20% citric acid, 2% hydroxypropyl methylcellulose and 10% polyethylene glycol 400 in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid.

[0055] (4) The above-mentioned curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0056] Example 4

[0057] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0058] (2) Mix 99% calcium phosphate powder and 1% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0059] (3) Dissolve 20% citric acid, 2% hydroxypropyl methylcellulose and 10% polyethylene glycol 400 in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid.

[0060] (4) The above-mentioned curing liquid and solid powder are uniformly mixed at a ratio of 0.6g / g to obtain calcium phosphate-based bone cement material.

[0061] Example 5

[0062] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0063] (2) Mix 99% calcium phosphate powder and 1% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0064] (3) Dissolve 20% citric acid, 2% hydroxypropyl methylcellulose and 10% polyethylene glycol 400 in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid.

[0065] (4) The above curing liquid and solid powder are uniformly mixed at a ratio of 0.4g / g to obtain calcium phosphate-based bone cement material.

[0066] Example 6

[0067] (1) Mix 65% of β-tricalcium phosphate and 35% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0068] (2) Mix 99% calcium phosphate powder and 1% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0069] (3) Dissolve 25% citric acid, 1% hydroxypropyl methylcellulose and 15% polyethylene glycol 400 in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid;

[0070] (4) The above-mentioned curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0071] Example 7

[0072] (1) Mix 55% of β-tricalcium phosphate and 45% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0073] (2) Mix 99% calcium phosphate powder and 1% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0074] (3) Dissolve 15% citric acid, 3% hydroxypropyl methylcellulose and 5% polyethylene glycol 400 in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid.

[0075] (4) The above-mentioned curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0076] Comparative Example 1

[0077] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain solid powder.

[0078] (2) Dissolve 20% citric acid, 2% hydroxypropyl methylcellulose and 10% polyethylene glycol 400 in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid.

[0079] (3) The above curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0080] Comparative Example 2

[0081] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain solid powder.

[0082] (2) Using deionized water as the curing liquid, the above curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0083] Comparative Example 3

[0084] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0085] (2) Mix 99.5% calcium phosphate powder and 0.5% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0086] (3) Dissolve 2% hydroxypropyl methylcellulose and 10% polyethylene glycol 400 in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid.

[0087] (4) The above-mentioned curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0088] Comparative Example 4

[0089] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0090] (2) Mix 99.5% calcium phosphate powder and 0.5% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0091] (3) Dissolve 20% citric acid and 10% polyethylene glycol 400 in deionized water by weight percentage to obtain a homogeneous liquid phase and a curing liquid;

[0092] (4) The above-mentioned curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0093] Comparative Example 5

[0094] (1) Mix 60% of β-tricalcium phosphate and 40% of anhydrous calcium dihydrogen phosphate powder evenly according to weight percentage to obtain calcium phosphate powder.

[0095] (2) Mix 99.5% calcium phosphate powder and 0.5% carbon nanotube powder evenly according to weight percentage to obtain solid powder.

[0096] (3) Dissolve 20% citric acid and 2% hydroxypropyl methylcellulose in deionized water according to the weight percentage to obtain a homogeneous liquid phase and a curing liquid;

[0097] (4) The above-mentioned curing liquid and solid powder are uniformly mixed at a ratio of 0.5g / g to obtain calcium phosphate-based bone cement material.

[0098] The performance of each embodiment and comparative example is characterized below:

[0099] Anti-collapse performance test:

[0100] Fill the prepared bone cement into a syringe, squeeze it into water, and let it stand for 10 minutes. Observe the degree of disintegration of the slurry with the naked eye to see if it can maintain its initial shape and whether particle freeing occurs.

[0101] Static anti-collapse properties were determined using bone cement materials from Examples 1-3, Example 6, and Comparative Examples 1, 4, and 5. Some test results are as follows: Figure 1 , 2 As shown, the bone cement in Comparative Example 1 exhibited poor anti-collapse properties; after standing for 10 minutes, many particles became loose, but it still maintained its initial shape. Comparative Examples 4 and 5 also showed good anti-collapse properties. In contrast, the bone cements prepared in Examples 1-3 and 6 maintained their initial shape after soaking in water for 10 minutes, with only a small number of particles becoming loose. Compared to Comparative Example 1, their anti-collapse properties were enhanced, demonstrating that the introduction of carbon nanotubes can also improve the anti-collapse properties of bone cement.

[0102] Determination of curing time:

[0103] Fill the prepared bone cement material (paste) into a plastic mold (2mm high, 8mm in diameter), and place it in a water bath at 37℃ for curing. At regular intervals, quickly remove the sample and use a Vicat apparatus to check whether the sample has solidified. If it has not solidified, continue to place it in the water bath for curing until it solidifies.

[0104] The comparative examples 1-3 and examples 1-5 were tested, and the results are as follows: Figure 3 As shown, the curing time measured in Comparative Example 1 was approximately 8.4 min. In Examples 1-3, after the addition of carbon nanotubes, the measured curing times were 6.54 min, 4.69 min, and 4.52 min, respectively, still indicating a relatively long operating time. The curing times for Examples 4 and 5 were 5.14 min and 2.34 min, respectively, showing that the curing time increases with the increase of the liquid-to-solid ratio. Comparative Examples 2 and 3, however, exhibited very fast curing speeds. Figure 4The diagram shows the bone cement mixing process. Comparative Examples 2 and 3 solidified during the mixing process, making them difficult to handle. The results indicate that the addition of citric acid and polyethylene glycol 400 can effectively delay the curing time, making it more workable. The addition of carbon nanotubes can accelerate the curing speed, and the curing speed further increases as the liquid-to-solid ratio decreases.

[0105] Injection performance test:

[0106] The prepared bone cement material (paste) was filled into a 2.5 ml syringe and injected using a universal testing machine. The indenter was extruded at a constant speed of 15 mm / min, with a maximum load of 100 N. The injection rate was determined by the ratio of the weight of the injected paste to the weight of the original slurry.

[0107] Injectability tests were conducted using Comparative Examples 1, 4, and 5 and Examples 2, 6, and 7. The results are shown in Table 1. The injection rate in Comparative Example 1 was 69.7%, while the injection rate in Example 2 was 59.3%. Figure 5 As shown, Examples 6, 4, and 5 can be injected relatively well. Example 7 requires a larger injection force. With the further increase of hydroxypropyl methylcellulose content, the cohesiveness of the bone cement further increases, requiring a larger injection force and increasing the injection difficulty. The results indicate that the addition of citric acid, hydroxypropyl methylcellulose, and polyethylene glycol improves the injectability of bone cement. However, increasing the hydroxypropyl methylcellulose content affects the injection capability, and the addition of carbon nanotubes affects the injectability of bone cement to some extent, but the bone cement is still injectable.

[0108] Table 1. Injection rate results of calcium phosphate bone cement

[0109]

[0110] Compressive strength determination:

[0111] The bone cement material (paste) was poured into a mold (12 mm high, 6 mm in diameter), cured in a 37°C water bath for 1 day, then demolded, rinsed with deionized water, and placed in anhydrous ethanol (EtOH) for 1 day to terminate curing. The compressive strength of the sample was tested using a universal testing machine at a loading rate of 1 mm / min.

[0112] Figure 6 The figures show the compressive strength results of Comparative Example 1 and Examples 1-3 of the present invention. As can be seen from the figures, the calcium phosphate bone cement containing carbon nanotubes has a high compressive strength.

[0113] Determination of hydration products:

[0114] The prepared bone cement material (paste) was filled into a mold (12 mm high and 6 mm in diameter), cured in a water bath at 37°C for 1 day, demolded, and cured for another 6 days. After rinsing with deionized water, the sample was placed in EtOH for 1 day to terminate curing. After drying thoroughly in an oven at 60°C, the sample was ground into powder. Finally, the cured sample was analyzed by XRD.

[0115] Hydration product analysis was performed using the bone cement materials prepared in Comparative Example 1 and Example 3. The results are as follows: Figure 7 As shown, the results indicate that the addition of carbon nanotubes accelerates the hydration reaction.

[0116] Determination of apatite mineralization properties:

[0117] Bone cement material (paste) was cured in a 37°C water bath for one day to obtain solidified discs. These discs were then immersed in simulated body fluid (SBF) for seven days, with the liquid sample being replaced every three days. The ratio of the immersed surface area to the SBF volume was set to 0.1 cm². 2 / mL. After the soaking time was completed, the sample was collected, the sample surface was washed with deionized water, and then placed in a 60℃ oven to dry thoroughly. The formation of apatite on the sample surface was observed using SEM and XRD.

[0118] Figure 8 This is a surface apatite deposition image of the bone cement in Example 3 of the present invention. Figure 9 The XRD patterns of surface mineralization of calcium phosphate bone cement in Examples 1-3 and Comparative Example 1 are shown. As can be seen from the figures, after soaking in SBF, a large amount of apatite can be deposited on the surface of the paste, indicating that the bone cement paste has excellent apatite deposition ability.

[0119] Cell viability assay:

[0120] The solidified bone cement was ground into powder, and then the powder was added to α-MEM cell culture medium for extraction. The concentration of bone cement powder in the medium was 0.5 mg / mL. The supernatant after centrifugation was collected to obtain the bone cement extract. BMSCs were used as experimental cells, and the cell viability of different bone cement materials was evaluated using a CCK-8 cell technology kit. BMSCs were added to the bone cement extract and cultured, followed by the addition of CCK-8 reagent and incubation at 37°C in the dark. Cell viability was then measured using a microplate reader.

[0121] Comparative Example 1 and Examples 1-3 were tested, and the cell viability results after 3 days of culture are as follows: Figure 10 As shown, the cell activity of Example 1 was higher than that of Comparative Example 1, while the cell activity of Examples 2 and 3 was comparable to that of Comparative Example 1. This indicates that the introduction of a small amount of carbon nanotubes gave the bone cement good cell activity, and the introduction of carbon nanotubes did not show cytotoxicity.

[0122] ARS staining assay:

[0123] The solidified bone cement was ground into powder, and then the powder was added to α-MEM cell culture medium for extraction. The concentration of bone cement powder in the medium was 0.5 mg / mL. The supernatant after centrifugation was collected to obtain the bone cement extract. First, BMSCs were cultured in the bone cement extract for 14 days. Then, the BMSCs were fixed with 4% formaldehyde and washed with PBS. The fixed cells were stained with ARS solution.

[0124] After ARS staining using Comparative Example 1, Examples 1, 2, and 3, the results are as follows: Figure 11 As shown, the addition of a small amount of carbon nanotubes gradually enhances the mineralization capacity of BMSCs cells. However, when the carbon nanotube content further increases, the mineralization capacity of BMSCs cells weakens, but they still retain osteoinductive ability. The results indicate that a small amount of carbon nanotubes imparts good osteoinductive ability to bone cement.

[0125] ALP staining assay:

[0126] The solidified bone cement was ground into powder, and then the powder was added to α-MEM cell culture medium for extraction. The concentration of bone cement powder in the medium was 0.5 mg / mL. The supernatant after centrifugation was collected to obtain the bone cement extract. First, BMSCs were cultured in the bone cement extract for 14 days, then fixed with 4% formaldehyde and washed with PBS. The fixed cells were then stained using an ALP staining kit.

[0127] After ALP staining using Comparative Example 1, Examples 1 and 2, the results are as follows: Figure 12 As shown, the ALP staining intensity gradually increases with the increase of carbon nanotube content, indicating that a small amount of carbon nanotubes gives bone cement good osteoinductive ability.

[0128] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. An injectable high-strength calcium phosphate-based bone cement, characterized in that, The bone cement is prepared from a solid powder and a curing liquid; the solid powder comprises calcium phosphate powder and carbon nanotubes, which are a mixture of β-tricalcium phosphate and anhydrous calcium dihydrogen phosphate; the curing liquid comprises at least an aqueous solution of citric acid, hydroxypropyl methylcellulose and polyethylene glycol.

2. The injectable high-strength calcium phosphate-based bone cement according to claim 1, characterized in that, The bone cement is prepared by mixing curing liquid and solid powder at a ratio of 0.4 to 0.6 g / g.

3. The injectable high-strength calcium phosphate-based bone cement according to claim 1, characterized in that, In the solid powder, the weight percentage of permealuminate powder is 98-99.5%, the weight percentage of carbon nanotubes is 0.5-2%, and the sum of the weight percentages of the two is 100%.

4. The injectable high-strength calcium phosphate-based bone cement according to claim 1, characterized in that, In the calcium phosphate powder, the weight percentage of β-tricalcium phosphate is 55-65%, and the weight percentage of anhydrous calcium dihydrogen phosphate is 35-45%.

5. The injectable high-strength calcium phosphate-based bone cement according to claim 1, characterized in that, The curing solution is an aqueous solution containing citric acid, hydroxypropyl methylcellulose and polyethylene glycol.

6. The injectable high-strength calcium phosphate-based bone cement according to claim 5, characterized in that, In the curing liquid, the weight percentage of citric acid is 15-25%, the weight percentage of hydroxypropyl methylcellulose is 1-3%, the weight percentage of polyethylene glycol is 5-15%, and the balance is water.

7. The method for preparing injectable high-strength calcium phosphate-based bone cement according to any one of claims 1 to 6, characterized in that, Includes the following steps: (1) β-tricalcium phosphate, anhydrous calcium dihydrogen phosphate and carbon nanotubes were uniformly mixed to obtain a solid powder. (2) Add citric acid, hydroxypropyl methylcellulose and polyethylene glycol to water and dissolve them completely to obtain a homogeneous liquid phase and a curing liquid; (3) Mix the solid powder and curing liquid in a uniform ratio to obtain the injectable high-strength calcium phosphate-based bone cement.

8. The use of the injectable high-strength calcium phosphate-based bone cement according to any one of claims 1 to 6 in dental and orthopedic filling and restorative materials.

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