Preparation method of porous metal element doped hydroxyapatite microspheres as well as product and application of porous metal element doped hydroxyapatite microspheres

Abstract

The invention relates to a preparation method of porous metal element doped hydroxyapatite microspheres as well as a product and application of the porous metal element doped hydroxyapatite microspheres. The preparation method comprises the following steps: firstly preparing beta-TCP uniformly doped with metal elements, mixing the beta-TCP with calcium carbonate powder to serve as reaction precursor powder, stirring a gelatin solution for dispersing the precursor powder and an oil phase solution at a high speed to form a water-in-oil emulsion, and curing at a low temperature to form gelatin microspheres; then, in the high-temperature calcination process of 1300-1400 DEG C, the gelatin template is decomposed, meanwhile, a precursor in the gelatin template is subjected to a solid-phase reaction, and the porous metal element doped hydroxyapatite microspheres are obtained. The microspheres with single particle size range distribution are prepared by adopting an emulsion method, then the high-temperature treatment step synchronously realizes microsphere shaping, pore generation and crystal phase conversion, and the process is simple and stable. The porous metal-doped hydroxyapatite microspheres have high specific surface area and stable mechanical strength, and the material performance can be directionally regulated and controlled by changing the types of doped metals, so that the requirements in different fields are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inorganic microsphere materials, in particular to a preparation method of porous metal element doped hydroxyapatite microspheres, a product thereof and application. BACKGROUND

[0002] Hydroxyapatite (HA) is the main inorganic mineral component of human bone and teeth. Due to its excellent biocompatibility, bone conduction and chemical stability, it has become an indispensable bioceramic material in the field of hard tissue repair and replacement. In recent years, by introducing functional metal ions (such as strontium, magnesium, zinc, silver, etc.) for doping, HA is endowed with new functions such as promoting osteogenesis, antibacterial and anti-inflammatory, or regulating degradation rate, which is the research frontier to improve its clinical performance.

[0003] Microsphere structure is attracting attention due to its unique advantages: it can provide a large specific surface area to promote cell adhesion and material exchange; as a filling material, it can perfectly adapt to irregular bone defect cavities; at the same time, it is an ideal sustained-release carrier for drugs or growth factors. Therefore, the development of hydroxyapatite materials with precise ion doping and regular microsphere morphology has great significance for the development of the next generation of high-performance bone repair materials. In addition, the unique electronic structure and surface activity of the surface of metal-doped porous HA microspheres make them also show unique prospects in the fields of heterogeneous catalysis, environmental adsorption repair and energy materials.

[0004] At present, the mainstream methods for preparing HA microspheres (such as spray drying method, emulsion method, hydrothermal method) can obtain spherical particles, but when combined with metal element doping process, they face significant challenges: for example, it is difficult to balance doping uniformity and morphology control, liquid phase coprecipitation method, etc. is easy to dope, but the subsequent granulation process is complex, and it is difficult to obtain microspheres with uniform size and high sphericity; many methods require multiple steps, such as first synthesizing powder, then forming a ball through a complex molding process, which has a long process, low yield and high cost; high temperature treatment leads to collapse of the morphology: if high temperature solid phase method is used to ensure complete doping reaction, traditional powder direct sintering will destroy the microsphere structure formed in advance, resulting in fusion or deformation. Therefore, the industry urgently needs to develop an integrated preparation technology that can simultaneously realize uniform doping of metal ions and precise preservation of microsphere morphology in high-temperature solid phase reaction. SUMMARY

[0005] In view of the urgent need in the industry for an integrated preparation technology that can simultaneously realize uniform doping of metal ions and precise preservation of microsphere morphology in high-temperature solid phase reaction, the present application aims to provide a preparation method of porous metal element doped hydroxyapatite microspheres.

[0006] Still another object of the present application is to provide a porous metal element doped hydroxyapatite microsphere product prepared by the above method.

[0007] Still another object of the present application is to provide an application of the above product.

[0008] The present application provides a method for preparing porous metal element doped hydroxyapatite microspheres, wherein first, β-tricalcium phosphate (β-TCP) doped with metal elements is mixed with calcium carbonate powder as a reaction precursor powder; a gelatin solution dispersing the precursor powder and an oil phase solution are mixed to form a "water-in-oil" emulsion under high-speed stirring, and the gelatin microspheres are obtained after low-temperature solidification; then, during high-temperature calcination at 1300-1400℃, the gelatin template is decomposed, and the precursor in the interior of the template undergoes solid-phase reaction to obtain the porous metal element doped hydroxyapatite microspheres.

[0009] The present application provides a new efficient and reliable method for preparing high-performance metal element doped hydroxyapatite microspheres, and realizes wide coverage of diversified high-end application demands on the same platform technology, thus having a broad application prospect.

[0010] A method for preparing porous metal element doped hydroxyapatite microspheres, comprising the following steps: (1) Preparation of precursor powder: β-TCP doped with metal elements is mixed with calcium carbonate at a mass ratio of 9:1-10:1 to obtain the precursor powder; (2) Preparation of microspheres by emulsion method: A gelatin aqueous solution with a concentration of 5-15% (w / v) is prepared at 60℃, the precursor powder is added to the gelatin solution as the water phase solution at a solid-liquid ratio of 0.5-1.5 g / mL, the water phase solution is added to 60℃ plant oil containing a surfactant at a volume ratio of 1:10-1:100, and the mixture is stirred and emulsified at 500-2000 rpm for 2 h to obtain an O / W type emulsion; the emulsion is transferred into an ice bath, physiological saline containing 0.1% triton-X is added as a demulsifier, and the mixture is continuously stirred for 2 h; the microspheres are extracted by centrifugation, washed with ethyl acetate and ethanol for 3 times respectively, and finally dispersed with pure water; the microspheres are freeze-dried for more than 48 h to obtain the microspheres; (3) The microspheres are calcined at 1200-1400℃ for 4-6 hours, and naturally cooled to room temperature in the furnace to obtain the porous metal element doped hydroxyapatite microspheres.

[0011] In step (1), the β-TCP doped with metal elements is prepared as follows: 1) Take calcium hydrogen phosphate, calcium carbonate as calcium source and phosphorus source, add the oxide or carbonate corresponding to the target metal element as a dopant according to the stoichiometric amount, so that the molar ratio of calcium hydrogen phosphate, calcium carbonate and target metal element is 2:0.997:0.003 to 2:0.85:0.15, that is, the molar substitution degree (the proportion of calcium ion substitution) of doped metal ions is controlled in 0.1% to 5%; The dopant at least includes one of ZnO, Fe2O3, MnO2, SrCO3, MgO, TiO2, Ag2CO3; 2) The above raw materials are placed in a pulverizer for dry mechanical mixing. The uniformly mixed powder is calcined at a temperature of 1200℃-1400℃ for 2 hours, and the furnace is naturally cooled to room temperature to obtain metal element doped β-TCP.

[0012] On the basis of the above scheme, in step (1), the mixing method is dry ball milling, so as to achieve uniform mixing at the molecular level.

[0013] In step (2), the surfactant is one or more of Tween 20, Tween 60, Tween 80, Span 80, and the concentration is 0.1-2% (w / v) of the oil phase solution.

[0014] The application also provides a porous metal element doped hydroxyapatite microsphere, which is prepared according to any of the above methods, and the particle size of the microsphere is in the range of 20-200 μm and can be single distributed.

[0015] The application also provides an application of the porous metal element doped hydroxyapatite microsphere, which is based on the biological properties or catalytic properties of hydroxyapatite endowed by metal elements, such as Mg enhancing toughness, Sr promoting osteogenesis, Zn or Ag endowing antibacterial properties, so as to meet different microsphere application scenarios.

[0016] The specific steps are as follows: 1) Take calcium hydrogen phosphate, calcium carbonate as calcium source and phosphorus source, add the oxide or carbonate corresponding to the target metal element as a dopant according to the stoichiometric amount, so that the molar ratio of calcium hydrogen phosphate, calcium carbonate and target metal element is 2:0.997:0.003 to 2:0.85:0.15, that is, the molar substitution degree (the proportion of calcium ion substitution) of doped metal ions is controlled in 0.1% to 5%; 2) The above raw materials are placed in a pulverizer for dry mechanical mixing. The uniformly mixed powder is calcined at a temperature of 1200℃-1400℃ for 2 hours, and the furnace is naturally cooled to room temperature to obtain metal element doped β-TCP; 3) The above metal doped β-TCP and calcium carbonate are weighed and mixed according to the mass ratio of 9:1-10:1, and the mixing method is dry ball milling, so as to achieve uniform mixing at the molecular level, and a precursor powder is obtained; 4. Prepare a 5-15% (w / v) gelatin aqueous solution at 60℃. Add the above precursor powder to the above gelatin solution at a solid-liquid ratio of 0.5-1.5 g / mL to form the aqueous phase solution; 5. Add the above aqueous solution to vegetable oil containing surfactant at a volume ratio of 1:10-1:100 to obtain an O / W type emulsion, and stir and emulsify at 500-2000 rpm for 2 hours. 6. Transfer the above emulsion to an ice bath, add physiological saline containing 0.1% triton-X as a demulsifier, and stir continuously for 2 hours; 7. Centrifuge to extract microspheres, wash three times with ethyl acetate and ethanol respectively, and finally disperse the microspheres with pure water and freeze-dry for more than 48 hours; 8. Place the above microspheres at 1200℃-1400℃ for 4-6 hours, and then let them cool naturally to room temperature to obtain porous metal element-doped hydroxyapatite microspheres.

[0017] The advantages of this invention are: 1. Microspheres with a single particle size distribution were prepared by emulsion method. The subsequent high-temperature treatment step simultaneously achieved microsphere shaping, pore formation and crystal phase transformation. The process is simple and stable.

[0018] 2. The porous hydroxyapatite microspheres prepared by this invention have high specific surface area and stable mechanical strength. The material properties can be directionally controlled by changing the type of doped metal to meet the needs of different fields. Attached Figure Description

[0019] Appendix Figure 1 XRD curves of porous metal element-doped hydroxyapatite microspheres prepared in Example 1, with relatively pure hydroxyapatite as the phase; Appendix Figure 2 The image shows a SEM image of porous metal element-doped hydroxyapatite microspheres prepared in Example 1. At low magnification, the microspheres appear as spherical particles with a uniform particle size range. Appendix Figure 3 The image shows a SEM image of porous metal element-doped hydroxyapatite microspheres prepared in Example 1. The microspheres exhibit a porous structure under high magnification. Detailed Implementation

[0020] The following embodiments are implemented based on the technical solution of the invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0021] Example 1 A porous metal element-doped hydroxyapatite microsphere is prepared according to the following steps: (1) Preparation of precursor powder: Take calcium hydrogen phosphate 2 mol, calcium carbonate 0.91 mol, manganese carbonate 0.09 mol, and place them in a pulverizer for dry mechanical mixing. Place the uniformly mixed powder in a furnace and calcine at 1400°C for 2 hours, and naturally cool to room temperature in the furnace. The 3% Mn-doped β-TCP is obtained. The metal element-doped β-TCP and calcium carbonate are weighed and mixed uniformly at a mass ratio of 9.3:1 to obtain a precursor powder; (2) Preparation of microspheres by emulsion method: Dissolve 0.5 g of gelatin in 10 mL of pure water to prepare a gelatin aqueous solution with a concentration of 5% (w / v) at 60°C. Disperse 10 g of the above-mentioned precursor powder into the gelatin solution, mix uniformly as the aqueous solution, and then add to 300 mL of olive oil containing 3 g of span-80. Stir and emulsify at 1000 rpm for 2 h to obtain an O / W emulsion. Transfer the obtained emulsion into an ice bath, add 300 mL of normal saline containing 0.1% triton-X as a demulsifier, and continue stirring for 2 h. After the reaction is completed, centrifugal extraction is performed to obtain the microspheres, which are washed with ethyl acetate and ethanol for 3 times respectively, and finally dispersed with pure water. Freeze-drying is performed for more than 48 h to obtain the microspheres. (3) Calcine the above-mentioned microspheres at a temperature of 1200°C-1400°C for 4-6 hours, and naturally cool to room temperature in the furnace to obtain the porous manganese-doped hydroxyapatite microspheres.

[0022] The XRD curve of the prepared porous manganese-doped hydroxyapatite microspheres is shown in FIG. 1, and the phase is relatively pure hydroxyapatite. Figure 1 The SEM image of the prepared porous manganese-doped hydroxyapatite microspheres is shown in FIG. 2, and the microspheres are spherical particles with uniform particle size range under low magnification, and the particle size of the microspheres is in the range of 20-50 μm. The SEM image of the prepared porous manganese-doped hydroxyapatite microspheres is shown in FIG. 2, and the microspheres are spherical particles with uniform particle size range under low magnification, and the particle size of the microspheres is in the range of 20-50 μm. Figure 2 The SEM image of the prepared porous manganese-doped hydroxyapatite microspheres is shown in FIG. 2, and the microspheres are spherical particles with uniform particle size range under low magnification, and the particle size of the microspheres is in the range of 20-50 μm. The SEM image of the prepared porous manganese-doped hydroxyapatite microspheres is shown in FIG. 2, and the microspheres are spherical particles with uniform particle size range under low magnification, and the particle size of the microspheres is in the range of 20-50 μm. Figure 3 The SEM image of the prepared porous manganese-doped hydroxyapatite microspheres is shown in FIG. 2, and the microspheres are spherical particles with uniform particle size range under low magnification, and the particle size of the microspheres is in the range of 20-50 μm.

[0023] Example 2 A porous metal element-doped hydroxyapatite microsphere, other steps are the same as those of Example 1, except that step (1) is prepared according to the following steps: The precursor powder is prepared: take calcium hydrogen phosphate 2 mol, calcium carbonate 0.85 mol, and titanium dioxide 0.15 mol, and place them in a pulverizer for dry mechanical mixing. Place the uniformly mixed powder in a furnace and calcine at 1400°C for 2 hours, and naturally cool to room temperature in the furnace. The 3% Ti-doped β-TCP is obtained. The metal element-doped β-TCP and calcium carbonate are weighed and mixed uniformly at a mass ratio of 9.3:1 to obtain a precursor powder. Steps (2) and (3) are the same as those of Example 1, and the porous titanium-doped hydroxyapatite microspheres are obtained.

[0024] Example 3 A porous metal element-doped hydroxyapatite microsphere is prepared using the same steps as in the example, except that step (1) is prepared according to the following steps: Precursor powder preparation: Weigh 2 mol of dicalcium phosphate, 0.97 mol of calcium carbonate, and 0.03 mol of strontium carbonate, and dry mechanically mix them in a pulverizer. Calcine the uniformly mixed powder at 1400℃ for 2 hours, and then allow it to cool naturally to room temperature to obtain 3% strontium-doped β-TCP. Weigh the metal-doped β-TCP and calcium carbonate at a mass ratio of 9.3:1 and mix them uniformly to obtain the precursor powder. Steps (2) and (3) are the same as in Example 1, and porous strontium-doped hydroxyapatite microspheres are obtained.

[0025] Example 4 A porous metal element-doped hydroxyapatite microsphere, with other steps being the same as in the example, except that step (2) of preparing the microspheres by emulsion method is carried out according to the following steps: 1 g of gelatin was dissolved in 10 mL of pure water to prepare a 5% (w / v) gelatin aqueous solution at 60 °C. 7.5 g of the precursor powder from Example 1 was dispersed into the gelatin solution and mixed evenly to form an aqueous phase solution. This solution was then added to 100 mL of olive oil containing 1 g of Span-80 to obtain an O / W emulsion. The emulsion was stirred at 1500 rpm for 2 h. The resulting emulsion was transferred to an ice bath, and 300 mL of physiological saline containing 0.1% Triton-X was added as a demulsifier. The mixture was stirred continuously for 2 h. After the reaction was completed, the microspheres were extracted by centrifugation, washed three times with ethyl acetate and ethanol, respectively, and finally dispersed in pure water. The microspheres were then freeze-dried for more than 48 h to obtain the microspheres. Steps (1) and (3) are the same as in Example 1, and porous manganese-doped hydroxyapatite microspheres are obtained.

Claims

1. A method for preparing porous metal element-doped hydroxyapatite microspheres, characterized in that, Includes the following steps: (1) Preparation of precursor powder: Metal-doped β-TCP was weighed and mixed with calcium carbonate at a mass ratio of 9:1-10:1 to obtain precursor powder. (2) Preparation of microspheres by emulsion method: A 5-15% (w / v) gelatin aqueous solution was prepared at 60℃. The precursor powder was added to the gelatin solution at a solid-liquid ratio of 0.5-1.5 g / mL to form the aqueous phase solution. The aqueous phase solution was then added to vegetable oil containing surfactant at a volume ratio of 1:10-1:100 at 60℃ to obtain an O / W emulsion. The emulsion was stirred and emulsified at 500-2000 rpm for 2 hours. The emulsion was then transferred to an ice bath, and physiological saline containing 0.1% Triton-X was added as a demulsifier. The mixture was stirred continuously for 2 hours. Microspheres were extracted by centrifugation, washed three times with ethyl acetate and ethanol, respectively, and finally dispersed in pure water. The microspheres were then freeze-dried for at least 48 hours to obtain the microspheres. (3) The above microspheres are calcined at 1200℃-1400℃ for 4-6 hours and then naturally cooled to room temperature to obtain porous metal element doped hydroxyapatite microspheres.

2. The method for preparing porous metal element-doped hydroxyapatite microspheres according to claim 1, characterized in that, In step (1), the preparation method of the metal element-doped β-TCP is as follows: 1) Using dicalcium phosphate and calcium carbonate as calcium and phosphorus sources, respectively, oxides or carbonates corresponding to the target metal element are added as dopants according to stoichiometry, so that the molar ratio of dicalcium phosphate, calcium carbonate and the target metal element is 2:0.997:0.003 to 2:0.85:0.15, that is, controlling the molar substitution degree of the doped metal ions, that is, the proportion of calcium ions substituted is between 0.1% and 5%; the dopants include at least one of ZnO, Fe2O3, MnO2, SrCO3, MgO, TiO2 and Ag2CO3; 2) Place the above raw materials in a pulverizer and dry mechanically mix them evenly; place the evenly mixed powder at a temperature of 1200℃-1400℃ for 2 hours, and let it cool naturally to room temperature with the furnace to obtain metal element doped β-TCP.

3. The method for preparing porous metal element-doped hydroxyapatite microspheres according to claim 1, characterized in that, In step (2), the surfactant is one or more of Tween 20, Tween 60, Tween 80, and Span 80, with a concentration of 0.1-2% (w / v) of the oil phase solution.

4. A method for preparing porous metal element-doped hydroxyapatite microspheres according to any one of claims 1 to 3, characterized in that, Prepare according to the following steps: (1) Preparation of precursor powder: Weigh 2 mol of dicalcium phosphate, 0.91 mol of calcium carbonate, and 0.09 mol of manganese carbonate, and dry mechanically mix them in a pulverizer; calcine the uniformly mixed powder at 1400℃ for 2 hours, and then allow it to cool naturally to room temperature to obtain 3% Mn-doped β-TCP; weigh the metal element-doped β-TCP and calcium carbonate at a mass ratio of 9.3:1 and mix them uniformly to obtain the precursor powder; (2) Preparation of microspheres by emulsion method: 0.5 g of gelatin was dissolved in 10 mL of pure water to prepare a 5% (w / v) gelatin aqueous solution at 60 °C. 10 g of the above precursor powder was dispersed into the gelatin solution and mixed evenly to form an aqueous phase solution. This solution was then added to 300 mL of olive oil containing 3 g of Span-80 to obtain an O / W emulsion. The emulsion was stirred at 1000 rpm for 2 h. The resulting emulsion was transferred to an ice bath, and 300 mL of physiological saline containing 0.1% Triton-X was added as a demulsifier. The mixture was stirred continuously for 2 h. After the reaction was completed, the microspheres were extracted by centrifugation, washed three times with ethyl acetate and ethanol, respectively, and finally dispersed in pure water. The microspheres were then freeze-dried for more than 48 h to obtain the microspheres. (3) The microspheres were calcined at 1200℃-1400℃ for 4-6 hours and then naturally cooled to room temperature to obtain porous manganese-doped hydroxyapatite microspheres.

5. The method for preparing porous metal element-doped hydroxyapatite microspheres according to claim 1 or 2, characterized in that, Step (1) The precursor powder is prepared according to the following steps: Weigh 2 mol of dicalcium phosphate, 0.85 mol of calcium carbonate, and 0.15 mol of titanium dioxide, and dry mechanically mix them in a pulverizer; calcine the uniformly mixed powder at 1400℃ for 2 hours, and then allow it to cool naturally to room temperature to obtain 5% Ti-doped β-TCP; weigh the β-TCP doped with this metal element with calcium carbonate at a mass ratio of 9.3:1 and mix them uniformly to obtain the precursor powder.

6. A method for preparing porous metal element-doped hydroxyapatite microspheres according to claim 1 or 2, characterized in that, Step (1) The precursor powder is prepared according to the following steps: Weigh out 2 mol of dicalcium phosphate, 0.97 mol of calcium carbonate, and 0.03 mol of strontium carbonate, and dry mechanically mix them in a pulverizer. Place the uniformly mixed powder at 1400℃ for 2 hours, and allow it to cool naturally to room temperature in the furnace to obtain 1% strontium-doped β-TCP. Weigh the metal-doped β-TCP and calcium carbonate at a mass ratio of 9.3:1 and mix them uniformly to obtain the precursor powder.

7. The method for preparing porous metal element-doped hydroxyapatite microspheres according to claim 1, characterized in that, Step (2) Preparation of microspheres by emulsion method: Follow these steps: 1 g of gelatin was dissolved in 10 mL of pure water to prepare a 5% (w / v) gelatin aqueous solution at 60 °C. 7.5 g of precursor powder was dispersed into the gelatin solution and mixed evenly to form an aqueous phase solution. This solution was then added to 100 mL of olive oil containing 1 g of Span-80 to obtain an O / W emulsion. The emulsion was stirred and emulsified at 1500 rpm for 2 h. After demulsification, the resulting emulsion was centrifuged to extract microspheres. The microspheres were washed three times with ethyl acetate and ethanol, respectively. Finally, the microspheres were dispersed in pure water and freeze-dried for more than 48 h to obtain the microspheres.

8. A porous metal element-doped hydroxyapatite microsphere, characterized in that, The microspheres prepared according to any one of claims 1-7 have a single distribution in particle size within the range of 20-200 μm.

9. The application of the porous metal element-doped hydroxyapatite microspheres according to claim 8, based on the metal elements imparting corresponding biological or catalytic properties to hydroxyapatite, such as Mg enhancing toughness, Sr promoting osteoogenesis, and Zn or Ag imparting antibacterial properties, so as to meet the needs of different microsphere application scenarios.

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