Method for modifying crystalline calcium phosphate particles into amorphous calcium phosphate by wet grinding

Abstract

Provided is a method for modifying crystalline calcium phosphate particles into amorphous calcium phosphate by wet grinding using a bead mill without causing particle aggregation. In a container of a bead milling device, a powder of crystalline calcium phosphate particles and milling beads are introduced at an apparent volume ratio of 1: 2-4, and acetone is introduced into the container at a weight ratio of 1: 5-10 with respect to a mixture of the calcium phosphate particle powder and the milling beads in the container and stirred. A slurry containing calcium phosphate particles and mill beads in acetone is prepared by using a bead mill, and a powder of crystalline calcium phosphate particles contained in the slurry is finely pulverized without aggregating the powder by rotating the bead mill at a prescribed rotational speed per minute while the slurry is housed in a container, thereby partially amorphizing the crystalline calcium phosphate particles.

Description

Technical Field

[0001] The present invention relates to a method for wet-crushing crystalline calcium phosphate particles using a bead mill apparatus to modify them into amorphous calcium phosphate, a method for supporting metal or metalloid ions on the modified amorphous calcium phosphate particles, and further relates to a bone regeneration material containing amorphous calcium phosphate particles produced by such a method and a method for producing the same. Background Art

[0002] Recently, a cotton-like artificial bone composed of biodegradable fibers in which calcium phosphate particles are compounded in a biodegradable resin has been used as a bone regeneration material. When the bone regeneration material is implanted at the affected site and comes into contact with body fluid, calcium ions and phosphate ions are supplied from the calcium phosphate particles contained in the biodegradable fibers at an appropriate concentration, thereby stimulating osteoblasts and affecting their activities.

[0003] As the calcium phosphate contained in the bone regeneration material, hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) are used. However, HAp hardly dissolves when it comes into contact with body fluid. Although β-TCP is dissolved by body fluid, since its dissolution rate is small, it remains in the body for a long time after the bone regeneration material is implanted at the affected site, and calcium ions and phosphate ions are gradually and slowly dissolved and absorbed.

[0004] There are reports that further bone formation is promoted by supplying metal or metalloid ions as biofunctional ions to the affected site together with calcium ions and phosphate ions (Non-Patent Document 1). Magnesium is known to have an effect of promoting cell adhesion. Boron-containing biomaterials are known to have a favorable effect on immune responses, and borate ions promote angiogenesis, which is one of the biological reactions closely related to bone repair. Silicon is known to stimulate osteoblasts. In addition, by supporting silver on biodegradable fibers, silver ions are dissolved from the fibers to exhibit antibacterial properties.

[0005] Ceramic particles such as calcium phosphate can be modified by applying impact energy to change their crystal structure. There are reports that when β-TCP particles are wet-crushed by applying impact energy using a ball mill, the crystalline particles are amorphized by mechanochemical reaction, resulting in increased solubility (Non-Patent Document 2).

[0006] In order to modify crystalline calcium phosphate particles into amorphous calcium phosphate by mechanical chemical reaction through wet grinding, a large impact energy needs to be applied to the particles. For this purpose, it is effective to use a planetary grinding device with high grinding ability and apply a large impact energy to the particles by grinding beads with a small median diameter. However, when wet grinding is performed using a bead mill, compared with the case of using a ball mill, although the particles are finely ground and the specific surface area becomes particularly large, on the other hand, there is a problem that the pulverized particles of the powder agglomerate. If the powder agglomerates, it is difficult to uniformly disperse the particles in the spinning dope by stirring the particles into the solvent, and the agglomerated particles settle near the bottom of the spinning tube used for spinning in the dispersion solvent solution, blocking the vicinity of the inlet of the nozzle through which spinning passes, resulting in the occurrence of an adverse situation where spinning becomes difficult.

[0007] Under the above circumstances, a method is sought for finely grinding crystalline calcium phosphate particles using a bead mill and modifying them into amorphous calcium phosphate without causing powder agglomeration, thereby improving or obtaining their solubility in body fluids. Furthermore, a method is sought for loading metal and metalloid ions on the calcium phosphate particles pulverized and modified in this way in a sustained-release manner. Prior art documents Non-patent literature

[0008] Non-patent literature 1: Creation of a metal ion sustained-release scaffold based on the activation mechanism of osteoblasts (Creation of a metal ion sustained-release scaffold based on the activation mechanism of osteoblasts) Materia Vol. 59, No. 11 (2020) Akiko Obata, Toshihiro Kasuga Non-patent literature 2: Mechanical activation and cement formation of β-tricalcium phosphate (Mechanical activation and cement formation of β-tricalcium phosphate) Biomaterials Vol. 24, No. 23, October 2003, pp. 4123-4131 (Biomaterials Volume 24, Issue 23, October 2003 pages 4123-4131) Summary of the invention Technical problems to be solved by the invention

[0009] To solve the above problems, the inventors of the present invention conducted in-depth research and found that due to grinding, the bonds on the surface of crystalline calcium phosphate particles are cut off, hydrogen attaches to the end of the P-O group, becoming a group called P-OH, and this OH group forms a hydrogen bond with water, and it bonds with other P-OH groups again, resulting in the particles sticking together to form aggregates. Based on this discovery, the inventors of the present invention thought that it is possible to use a substance that does not dissociate H in wet grinding +A non-polar solvent is used to effectively prevent hydrogen bond formation between the crushed particles.

[0010] Based on the above ideas, the inventors of the present invention have completed an invention of a method for wet-crushing crystalline calcium phosphate particles using a bead mill device and modifying them into amorphous calcium phosphate. Among them, In the container of the bead mill device, a powder of crystalline calcium phosphate particles with a diameter of 1 to 5 μm and grinding beads with a median diameter of 0.015 to 2.0 mm are put in an amount such that the apparent volume ratio of the former to the latter is 1:2 to 4. For the mixture of the crystalline calcium phosphate particle powder and the grinding beads in the container, acetone is put in an amount such that the weight ratio of the former to the latter is 1:5 to 10 and stirred, thereby preparing a slurry containing the calcium phosphate particles and the grinding beads in the acetone. In a state where the slurry is contained in the container, the bead mill device is rotated at a specified number of revolutions per minute for a specified time. By this, the powder of the calcium phosphate particles contained in the slurry is finely crushed to a particle size of 0.1 to 1.2 μm without causing them to aggregate, and is impacted by the grinding beads to partially amorphousize the crystalline calcium phosphate particles and reduce the crystallinity to 50 to 10%.

[0011] Preferably, the bead mill device uses a planetary device having a self-rotation and revolution function.

[0012] Preferably, the crystalline calcium phosphate particles are β-TCP or HAp.

[0013] Preferably, the metal salt is silver phosphate.

[0014] Preferably, the semi-metal salt is silicate or borate.

[0015] Preferably, the powder of the crystalline calcium phosphate particles is mixed with the powder of the metal salt particles or the semi-metal salt particles at a weight ratio of 0.99 to 0.9 to 0.01 to 0.1. The mixture of the powders is put into the container of the planetary bead mill device together with a specified amount of acetone and grinding beads, and the planetary bead mill device is rotated at a high speed at a specified number of revolutions per minute. By this, the metal ions or semi-metal ions separated from the metal salt particles or the semi-metal salt particles are coordinated to the phosphate ions of the amorphous calcium phosphate particles.

[0016] The inventors of the present invention have also completed an invention of calcium phosphate particles, which are calcium phosphate particles carrying metal ions or semi-metal ions in a sustained-release manner. Among them, The crystal structure of the crystalline calcium phosphate particles of the calcium phosphate particles is partially modified to an amorphous state by performing a bead mill treatment. By coordinating metal or metalloid ions on the amorphized portion of the crystalline calcium phosphate particles, the metal or metalloid ions are supported on the calcium phosphate particles in a sustained-release manner. When the calcium phosphate particles carrying the metal or metalloid ions are implanted into a living body and come into contact with body fluid, the amorphized calcium phosphate particles are dissolved, and the metal or metalloid ions are released sustainedly together with calcium ions and phosphate ions.

[0017] Preferably, the bead milling treatment uses a planetary device having a rotation and revolution function.

[0018] Preferably, the crystalline calcium phosphate particles are β-TCP or HAp.

[0019] Preferably, the metal salt is silver phosphate.

[0020] Preferably, the metalloid salt is silicate or borate.

[0021] The inventors of the present invention have also completed an invention of a method for manufacturing a bone regeneration material, which is a method for manufacturing a bone regeneration material composed of biodegradable fibers containing calcium phosphate particles modified into an amorphous state. The manufacturing method includes the following steps: In a container of a bead mill, a powder of crystalline calcium phosphate particles with a diameter of 1 to 5 μm and grinding beads with a median diameter of 0.015 to 2.0 mm are put in an amount such that the apparent volume ratio of the former to the latter is 1:2 to 4. For the mixture of the crystalline calcium phosphate particle powder and the grinding beads in the container, acetone is put in an amount such that the weight ratio of the former to the latter is 1:5 to 10 and stirred, thereby preparing a slurry containing the calcium phosphate particles and the grinding beads in the acetone. In a state where the slurry is accommodated in the container, the bead mill is rotated at a specified rotational speed per minute for a specified time. Thereby, the powder of the crystalline calcium phosphate particles contained in the slurry is pulverized to a particle size of 0.1 to 1.2 μm without causing aggregation thereof, and the crystalline calcium phosphate particles are partially amorphized and the crystallinity is reduced to 50 to 10% by being impacted by the grinding beads. The powder of the amorphized calcium phosphate particles and a biodegradable resin are put into a solvent and stirred, thereby preparing a spinning dope in which the amorphized calcium phosphate particles are dispersed. The spinning dope is filled into a spinning tube of a spinning device and extruded from a nozzle for spinning, and the obtained biodegradable fibers are stacked on a collector for recovery.

[0022] Preferably, the bead mill uses a planetary device having a rotation and revolution function.

[0023] Preferably, the crystalline calcium phosphate particles are β-TCP or HAp.

[0024] Preferably, a metal or metalloid ion is bonded to the calcium phosphate particles modified to be amorphous.

[0025] The inventors of the present invention have also completed an invention of a bone regeneration material, which is a bone regeneration material composed of biodegradable fibers containing calcium phosphate particles modified to be amorphous, and is manufactured by a method including the following steps: In a container of a bead mill device, a powder of crystalline calcium phosphate particles with a diameter of 1 to 5 μm and grinding beads with a median diameter of 0.015 to 2.0 mm are put in an amount such that the apparent volume ratio of the former to the latter is 1:2 to 4. For the mixture of the crystalline calcium phosphate particle powder and the grinding beads in the container, acetone is put in an amount such that the weight ratio of the former to the latter is 1:5 to 10 and stirred, thereby preparing a slurry containing the calcium phosphate particles and the grinding beads in the acetone. In a state where the slurry is contained in the container, the bead mill device is rotated at a specified rotational speed per minute for a specified time, whereby the powder of the crystalline calcium phosphate particles contained in the slurry is pulverized to a particle size of 0.1 to 1.2 μm without causing agglomeration, and is impacted by the grinding beads to partially amorphousize the crystalline calcium phosphate particles and reduce the crystallinity to 50 to 10%. The powder of the amorphousized calcium phosphate particles is put into a solvent together with a biodegradable resin and stirred, thereby preparing a spinning dope in which the amorphousized calcium phosphate particles are dispersed. The spinning dope is filled into a spinning tube of a spinning device and extruded from a nozzle for spinning, and the obtained biodegradable fibers are stacked on a collector for recovery.

[0026] Preferably, the bead mill device uses a planetary device having a function of self-rotation and revolution.

[0027] Preferably, the calcium phosphate particles are β-TCP or HAp.

[0028] Preferably, the metal or metalloid ion is supported on the calcium phosphate particles modified to be amorphous in a manner capable of sustained release. Advantages of the Invention

[0029] By subjecting the crystalline calcium phosphate particles to an amorphousization treatment by bead milling according to the present invention, it is possible to make HAp, which is insoluble in an aqueous solution, soluble, and to improve the solubility of β-TCP, which has a slow dissolution rate.

[0030] By implanting calcium phosphate particles that have been micronized and amorphized through bead milling treatment of the present invention into a living body, calcium ions and phosphate ions can be supplied from the calcium phosphate particles as soon as possible after implantation.

[0031] Through the bead milling treatment of the present invention, calcium phosphate particles are micronized and amorphized. The particles are charged on the surface, enabling metal and metalloid ions to be loaded on the particles, and the phenomenon of the particles colliding with each other and integrating continuously occurs, thus making it possible to contain metal and metalloid ions. By implanting calcium phosphate particles containing metal and metalloid ions into a living body, metal or metalloid ions can be slowly released from the calcium phosphate particles together with calcium ions and phosphate ions after implantation.

[0032] The calcium phosphate particles micronized and amorphized through the bead milling treatment of the present invention do not aggregate. Therefore, by putting the powder of the particles together with a biodegradable resin into a solvent and stirring, the micronized powder can be easily dispersed and contained in the spinning dope. Using the spinning dope prepared in this way, a bone regeneration material in which calcium phosphate particles are uniformly dispersed and contained in a biodegradable fiber can be manufactured by the electrospinning method or the wet spinning method.

[0033] In the present invention, by preparing a spinning dope dispersedly containing micronized, amorphized calcium phosphate particles loaded with metal or metalloid ions and performing spinning using the electrospinning method or the wet spinning method to make it biodegradable, an excellent bone regeneration material having both high osteogenic ability and antibacterial property and / or angiogenesis ability can be manufactured. Description of the Drawings

[0034] Figure 1 (A) shows an external photograph of a planetary bead mill device used in one embodiment of the present invention, Figure 1 (B) shows a schematic diagram of the rotation and revolution of the device. Figure 2 (A) shows a scanning electron microscope (SEM) image of β-TCP particles that have undergone the bead milling treatment of the present invention for 120 minutes, Figure 2 (B) shows the particle size distribution obtained from the image. In the figure, the histogram represents the number of particles, and the curve represents the cumulative number of particles. Figure 3 Shows the relationship between the bead milling treatment time of the present invention and the particle size of β-TCP, and shows the particle sizes at the 10%, 50%, and 90% positions in the cumulative particle size distribution curve. Figure 4 Shows the relationship between the bead milling treatment time of the present invention and the specific surface area of the obtained powder. In the figure, a bead milling time of 0 represents the powder before treatment. Figure 5It is the powder X-ray diffraction pattern of the product obtained by ball milling β-TCP (crushed product manufactured by Taihei Chemical Industry Co., Ltd.), acetone, and 1 mm Φ zirconia beads with a weight ratio of β-TCP:acetone:1 mm Φ zirconia beads of 1:7.5:22.5 and a total weight of 55.8 g. They were added to a 45 mL zirconia container and subjected to planetary rotation at a revolution speed of 400 rpm and a rotation speed of 800 rpm for 120 minutes. The spectrum of CuKα 2θ = 20 - 43° was deconvolved using a Gaussian function to separate the crystalline phase peak and the amorphous phase peak. The dotted line in the figure was separated as the peak of the amorphous phase. Figure 6 It shows the relationship between the ball milling treatment time of the present invention and the amorphous phase content in the obtained powder. In the figure, a ball milling time of 0 represents the powder before treatment. 31 The peaks of the P solid nuclear magnetic resonance MAS-NMR spectrum were deconvolved using a Gaussian function to separate the crystalline phase and the amorphous phase, and the content ratio of the amorphous phase was plotted. Figure 7 It is the result of determining the amounts of calcium ions and phosphate ions dissolved after immersing 30 mg of powder in 20 mL of 37 °C tris-HCl buffer solution (pH 7.40) for 24 hours by high-frequency inductively coupled plasma atomic emission spectrometry ICP-AES. Figure 8 It is the SEM photograph of the product obtained by ball milling β-TCP (crushed product manufactured by Taihei Chemical Industry Co., Ltd.), silver phosphate (Ag3PO4 manufactured by Fujifilm Wako Pure Chemical Corporation), acetone, and 1 mm Φ zirconia beads with a weight ratio of β-TCP:silver phosphate:acetone:1 mm Φ zirconia beads of 0.99:0.01:7.5:22.5 and a total weight of 55.8 g. They were added to a 45 mL zirconia container and subjected to planetary rotation at a revolution speed of 400 rpm and a rotation speed of 800 rpm for ball milling. Figure 9 It is the Ag3d spectrum obtained by subjecting the product obtained by ball milling β-TCP (crushed product manufactured by Taihei Chemical Industry Co., Ltd.), silver phosphate (Ag3PO4 manufactured by Fujifilm Wako Pure Chemical Corporation), acetone, and 1 mm Φ zirconia beads with a weight ratio of β-TCP:silver phosphate:acetone:1 mm Φ zirconia beads of 0.99:0.01:7.5:22.5 and a total weight of 55.8 g. They were added to a 45 mL zirconia container and subjected to planetary rotation at a revolution speed of 400 rpm and a rotation speed of 800 rpm for grinding, and then performing X-ray photoelectron spectroscopy on the resulting product. The peaks were deconvolved using a Gaussian function, and the peak intensities of Ag ions appearing at 368 eV and metallic Ag appearing at 369 eV were compared. The results showed that almost all silver was introduced in the ionic form. Figure 10It shows the results of weighing β-TCP (ground product manufactured by Taihei Chemical Industry Co., Ltd.), silver phosphate (Ag3PO4 manufactured by Fujifilm Wako Pure Chemical Corporation), acetone, and 1 mm Φ zirconia beads in a weight ratio of β-TCP:silver phosphate:acetone:1 mm Φ zirconia beads of (1-x):x:7.5:22.5 (x = 0, 0.01, 0.05) with a total weight of 55.8 g, adding them to a 45 mL zirconia container, performing bead milling with planetary rotation at a revolution speed of 400 rpm and a rotation speed of 800 rpm, immersing 80 mg of the bead milled product in 40 mL of HEPES buffer solution at 37°C for 24 hours, and measuring the amounts of dissolved calcium ions, phosphate ions, and silver ions by ICP-AES. Figure 11 They are the transmission electron microscope TEM images and electron diffraction images of β-TCP particles treated by bead milling for 120 minutes. Figure 12 It is the XRD pattern after immersing the β-TCP particles treated by bead milling for 120 minutes in tris-HCl buffer solution at 37°C for 72 hours. Figure 13 It shows the XRD patterns of the products obtained by weighing β-TCP (ground product manufactured by Taihei Chemical Industry Co., Ltd.), acetone or water, and 1 mm Φ zirconia beads in a weight ratio of β-TCP:acetone or water:1 mm Φ zirconia beads of 1:7.5:22.5 with a total weight of 55.8 g, adding them to a 45 mL zirconia container, and performing bead milling with planetary rotation at a revolution speed of 400 rpm and a rotation speed of 800 rpm for 120 minutes. Figure 14 It shows the SEM images of the particles obtained by mixing and grinding β-TCP powder and B2O3 powder by bead milling according to the present invention. Those without B2O3 are denoted as 0B-CP, and those mixed with 10 - 30% B2O3 are denoted as 10 - 30B-CP. Various shapes are shown with particle sizes of about 0.1 μm - 1 μm. Figure 15 (A), (B), (C) show Figure 14 the EDS surface scan images of the particles. Figure 15 (A) shows the particles mixed with 10% B2O3, Figure 15 (B) shows the particles mixed with 20% B2O3, Figure 15 (C) shows the particles mixed with 30% B2O3. Figure 16 It shows Figure 14 the XRD patterns of the particle powders. They are recorded as those without B2O3: 0B-CP, and those mixed with 10 - 30% B2O3: 10 - 30B-CP. Figure 17 It shows Figure 1411B MAS-NMR spectrum of the powder of the particles (particles mixed with 10 - 30% B2O3). Q represents boron coordinated with 4 oxygen atoms, and T 2 represents boron coordinated with 3 oxygen atoms and 2 oxygen atoms are crosslinked oxygen atoms, and T 3 represents boron coordinated with 3 oxygen atoms and all oxygen atoms are crosslinked oxygen atoms. Figure 18 Shows Figure 14 of the powder of the particles 31 P MAS-NMR spectrum (recorded as 0B-CP for those without B2O3 and 10 - 30B-CP for those mixed with 10 - 30% B2O3). Figure 19 (A), (B), (C) show the Figure 14 ion dissolution amount after immersing the powder of the particles in tris-HCl buffer solution. In the figure, 0B-CP represents those without B2O3, and 10 - 30B-CP represents those mixed with 10 - 30% B2O3. Figure 20 Shows the Figure 14 XRD spectrum of the powder after immersing the powder of the particles in tris-HCl buffer solution for 120 minutes (recorded as 0B-CP and 10 - 30B-CP for those mixed with 10 - 30% B2O3). Figure 21 Shows the XRD spectrum of the particles obtained by mixing and pulverizing β-TCP powder and SiO2 powder through the bead milling treatment of the present invention. Also shows the XRD spectra of β-TCP powder for comparison and bead milled β-TCP powder. Figure 22 (A) shows the elemental surface scan obtained by energy dispersive X-ray spectroscopy EDS of the particles obtained by mixing and pulverizing β-TCP powder and SiO2 powder in a weight ratio of 95 to 5 through the bead milling treatment of the present invention, Figure 22 (B) shows the spectra at points 1 - 5. Figure 23 Shows the respective ion concentrations after immersing 50 mg of β-TCP powder mixed with 5% SiO2 in 20 mL of 37 °C tris-HCl buffer solution for a specified time. Figure 24 Shows Figure 23 XRD spectrum of the powder after immersion in tris-HCl buffer solution in Figure 25(A) shows the amount of calcium ions in the solution after impregnating biodegradable fibers (Fiber A) obtained by mixing bead-milled calcium phosphate particle powder (m-TCP) and poly(D,L-lactic acid-gluconic acid) copolymer (PDLLGA) at a weight ratio of 70:30, fibers (Fiber B) with a weight ratio of β-TCP:m-TCP:PDLLGA of 35:30:30, and fibers (Fiber C) with a weight ratio of β-TCP:PDLLGA of 70:30 in a tris-HCl buffer solution with a pH value of 7.40 for a specified time. Figure 25 (B) shows the amount of phosphate ions in the solution after impregnating biodegradable fibers (Fiber A) obtained by mixing bead-milled calcium phosphate particle powder (m-TCP) and poly(D,L-lactic acid-gluconic acid) copolymer (PDLLGA) at a weight ratio of 70:30, fibers (Fiber B) with a weight ratio of β-TCP:m-TCP:PDLLGA of 35:30:30, and fibers (Fiber C) with a weight ratio of β-TCP:PDLLGA of 70:30 in a tris-HCl buffer solution with a pH value of 7.40 for a specified time. Figure 26 Shows after impregnating in a tris-HCl buffer solution for 72 hours Figure 25 XRD spectra of the fibers. Detailed implementation mode

[0035] Hereinafter, the preferred implementation modes of the present invention will be described with reference to the accompanying drawings. Term definition

[0036] <Bead milling treatment> In the present invention, "bead milling treatment" refers to a treatment performed using small-diameter grinding beads as the grinding medium of a milling device for mechanochemical treatment. The diameter of the grinding balls used as the grinding medium in a normal ball mill is 10 - 50 mm, while the diameter of the grinding beads used as the grinding medium in bead milling treatment is 0.015 - 0.5 mm. By using small-diameter grinding beads as the grinding medium, compared with the case of using grinding balls with a diameter of 10 - 50 mm, for calcium phosphate particles, 100 - 500 times stronger energy can be provided to the particles.

[0037] <Ball mill device> In the present invention, "ball mill device" refers to a crusher for performing mechanochemical treatment on particles, which uses grinding balls with a diameter of 10 - 50 mm as the grinding medium. The planetary ball mill can crush particles with higher efficiency by applying impacts by alternately and repeatedly rotating and revolving the particles in the input container.

[0038] <Bead mill device> In the present invention, the "bead mill device" refers to a pulverizer for subjecting particles to mechanochemical treatment, which uses grinding beads with a diameter of 0.015 to 0.5 mm as the pulverizing medium (refer to Figure 1 (A)). The planetary bead mill device can alternately and repeatedly rotate and revolve the particles put into the container, so that a strong impact energy can be applied to the particles by the grinding beads used as the pulverizing medium, and the particles can be pulverized with higher pulverizing efficiency (refer to Figure 1 (B)). There are different types and models of bead mills in the bead mill device, but as long as the calcium phosphate particles can be finely pulverized by the grinding beads, any of them can be used as the bead mill device of the present invention.

[0039] <Wet pulverization> In the present invention, "wet pulverization" refers to a method of putting a mixture of powder and liquid (solvent), i.e., slurry, and grinding balls or beads into a container and stirring and pulverizing them, as opposed to dry pulverization of pulverizing without mixing liquid (in air). If pulverization is carried out dry in ball milling treatment / bead milling treatment, the load on the pulverized particles will become larger and larger and blockage will occur, and hard aggregates are likely to be formed during the pulverization process. Therefore, wet pulverization is adopted in the present invention. However, even if wet pulverization is adopted, if a polar liquid that can dissociate H + is used as the solvent, the pulverized particles will also form hydrogen bonds and aggregate. Therefore, measures need to be taken to prevent the pulverized particles from aggregating.

[0040] <Hydrogen bond> Academically, a hydrogen bond is a non-covalent interaction force formed by a hydrogen atom covalently bonded to an electronegative atom (negative atom) by a covalent bond and a lone pair of electrons such as nitrogen, oxygen, sulfur, fluorine, and π electron system located nearby. However, in the present invention, "hydrogen bond" refers to the H + bonded and electronegative δ - formed by the calcium phosphate particles finely pulverized and non-crystallized by a bead mill and the H + dissociated from the solvent used for wet pulverization, and in this state, the H + bonded to the adjacent calcium phosphate particles is attracted electrostatically, resulting in a phenomenon of weak electric bonds being generated between the particles. When water is used as the solvent for wet pulverization using a bead mill, since water is a polar molecule and can dissociate H + , the calcium phosphate particles pulverized by the bead mill are easily hydrogen-bonded to each other, and as a result, particle aggregation is likely to occur. Acetone (C3H6O), on the other hand, is a non-polar molecule that does not dissociate H

[0041] <Metal ions, metalloid ions> In the present invention, the "metal ions" refer to metal ions separated from metal salt particles when the powder of metal salts such as magnesium and silver is subjected to the impact energy of a bead mill. In a preferred embodiment of the present invention, the metal ions separated from the metal salt particles recombine with calcium phosphate particles whose chemical potential has increased due to the impact energy of the bead mill. In the present invention, the "metalloid ions" refer to metalloid ions separated from metalloid salt particles when the powder of metalloid salts such as silicon and boron is subjected to the impact energy of a bead mill. In a preferred embodiment of the present invention, the metalloid ions separated from the metalloid salt particles recombine with calcium phosphate particles whose chemical potential has increased due to the impact energy of the bead mill.

[0042] Embodiment 1 (subjecting β-TCP particles to bead milling to amorphize them) (1) In a zirconia pot (volume capacity 30 - 60 ml) of a planetary bead mill, 35 - 50 g of a powder of β-TCP particles with a diameter of 1 - 5 μm and grinding beads with a diameter of 0.6 - 1.4 mm are taken together in an amount such that the apparent volume ratio of the two is 1:2 - 4 (when the median diameter of the grinding beads is large, the gap between the grinding beads becomes large and the apparent volume becomes large, and conversely, when the median diameter of the grinding beads is small, the gap between the grinding beads becomes small and the apparent volume becomes small). Then, 15 - 20 ml of acetone is added, and the planetary ball mill is rotated around its axis and revolved around the sun at a specified speed. (2) The β-TCP particles subjected to the impact of the grinding beads are pulverized and the particle size is reduced to 0.1 - 1.2 μm ( Figure 2 、 3 ), the specific surface area is increased by 3 - 5 times ( Figure 4 ), and at the same time, the crystal structure of the β-TCP particles is partially amorphized and the crystallinity is reduced to 50 - 10% ( Figure 5 、 Figure 6 ). The powder of the β-TCP particles refined by pulverization does not agglomerate. (3) When the powder of the amorphized β-TCP particles is immersed in an aqueous solution (tris-HCl buffer solution with a pH value of 7.40), β-TCP dissolves, and calcium ions and phosphate ions are dissolved out from the particles ( Figure 7 ).

[0043] Embodiment 2 (amorphizing β-TCP particles and loading metal ions) (1) The powder of β-TCP particles and the powder of metal salt particles are mixed at a weight ratio of 0.99 - 0.99 to 0.01 - 0.1. The mixture of the powders, 15 - 20 ml of acetone, and 35 - 50 g of grinding beads with a diameter of 0.6 - 1.4 mm are put into a zirconia container (volume capacity 30 - 60 ml) of a planetary ball mill, and the planetary ball mill is rotated around its axis and revolved around the sun at a specified speed. (2) The β-TCP particles impacted by the grinding beads are crushed, resulting in a reduced particle size and an increased specific surface area. At the same time, the crystal structure of the β-TCP particles is partially amorphous. The metal salt particles placed in the zirconia container of the planetary ball mill device are impacted by the grinding beads, and metal ions are separated from the particles. The separated metal ions coordinate with the phosphate ions of the amorphous β-TCP particles. (3) After continuously rotating at a high speed in the planetary ball mill device for a certain period of time and then standing still, the state in which the metal ions separated from the metal salt particles coordinate and bond with the phosphate ions of the above-mentioned amorphous β-TCP particles is fixed ( Figure 8 , Figure 9 ). Then, the metal salt particles are separated from the powder mixture by sieving and rinsing, and the β-TCP particles containing metal ions are recovered.

[0044] The β-TCP particles with a partially amorphous crystal structure due to bead milling treatment have a higher solubility in aqueous solutions or body fluids compared to the β-TCP particles without bead milling treatment, and will be dissolved by the aqueous solution or body fluid and quickly release calcium ions and phosphate ions ( Figure 7 ). In addition, the metal ions bonded to the amorphous and ionized β-TCP particles will be released together with calcium ions and phosphate ions as the β-TCP particles dissolve ( Figure 10 ).

[0045] The mechanism of using a bead mill to crush particles and form an amorphous phase and support metal and metalloid ions is not necessarily clear. However, according to the inventors of the present invention, when beads (about 1 mm in diameter) are put into the container of the bead mill and calcium phosphate (β-TCP) powder and metal salt particle powder are put in and rotated at high speed, a huge energy caused by intense mechanical impact is applied to the particles constituting the powder. Thereby, the bonds constituting the particles are cut or distorted. When the bonds of calcium phosphate particles are cut or distorted, their chemical potential (if multiplied by the amount of substance, it is chemical energy) is in a higher state. Once the bond is cut, according to the surrounding conditions, it cannot remain in this state (ion) all the time. Therefore, it will bond with nearby ions again to lower the electric potential. If metal salt particles such as silver phosphate and magnesium oxide or metalloid salt particles such as silicate and boron compound are mixed in the calcium phosphate particles, the same situation will occur with these compounds. Metal or metalloid ions will be separated from the metal salt particles or metalloid salt particles, and the separated metal or metalloid ions will bond with the calcium phosphate particles with a higher chemical potential again. During the high-speed rotation of the ball mill, impact energy is continuously applied. Therefore, there is not enough time to restore to the original bond with the lowest chemical potential, and the state of being unable to be neatly arranged continues. Even in a state with slightly higher energy, the energy is lower than when existing alone. Thus, the configuration of ions becomes a random state. Once the external energy is no longer applied after crushing, as a result, the ions can no longer move, so it solidifies into amorphous calcium phosphate almost as it is. In the crushing and mixing environment, calcium ions, silver ions and phosphate ions or borate ions coexist, and they form a bonding state (amorphous state) with a random configuration (weaker than the bonding of the original compound).

[0046] Embodiment 3 (Amorphizing β-TCP particles and supporting metalloid ions) (1) Mix the powder of β-TCP particles and the powder of metalloid salt particles in a weight ratio of 0.99 - 0.9 to 0.01 - 0.1 in the same method as in Embodiment 2. Put the mixture of the powders together with a specified amount of acetone and beads into the zirconia container of the planetary ball mill. Make the planetary ball mill device revolve and rotate at a certain speed. Thereby, the β-TCP particles are crushed to reduce their particle size and increase their specific surface area. (2) Subjected to the impact of the beads, the crystal structure of the β-TCP particles is partially amorphized and partially ionized, and the metalloid ions are separated from the metalloid salt particles, and the separated metalloid ions are coordinated on the phosphate ions of the β-TCP particles. (3) By allowing the high-speed rotation of the planetary ball mill device to continue for a certain period of time and then standing still, the state where metal ions separated from metal salt particles are coordinately bonded to phosphate ions of the above-mentioned amorphous β-TCP particles is fixed. After the fixing process, the metal salt particles are separated from the above-mentioned powder mixture by sieving and rinsing, and β-TCP particles containing metal ions are recovered.

[0047] Compared with β-TCP particles whose crystal structure is partially amorphous due to bead milling treatment and β-TCP particles without bead milling treatment, the solubility of β-TCP particles in body fluids is high, and they will be dissolved by body fluids to dissolve and release calcium ions and phosphate ions. Moreover, the metal ions bonded to the ionized β-TCP particles due to amorphization will be released into the affected area in the body together with calcium ions and phosphate ions as the β-TCP particles dissolve, promoting bone formation.

[0048] Embodiment 4 (Amorphizing HAp particles and loading metal ions or metalloid ions) (1) In the same manner as in Embodiment 2, the powder of HAp particles and the powder of metal salt particles or metalloid salt particles are mixed at a ratio of 0.99 - 0.9 to 0.01 - 0.1 by weight, and then the powder mixture, a specified amount of acetone, and grinding beads with a specified diameter are put into a zirconia container of a planetary ball mill device. The planetary ball mill device is rotated around the sun and rotated on its own axis at a specified speed. (2) Subjected to the impact of the grinding beads, the HAp particles are crushed, the particle size is reduced, the specific surface area is increased, and the crystal structure of the HAp particles is partially amorphous and partially ionized. Metal ions or metalloid ions are separated from the metal salt particles or metalloid salt particles, and the separated ions are coordinated on the phosphate ions of the HAp particles. (3) By allowing the high-speed rotation of the planetary ball mill device to continue for a certain period of time and then standing still, the state where metal or metalloid ions separated from the above-mentioned metal salt particles or metalloid ions are coordinately bonded to phosphate ions of the above-mentioned amorphous HAp particles is fixed. After the fixing process, the metal or metalloid salt particles are separated from the above-mentioned powder mixture by sieving and rinsing, and HAp particles containing metal ions or metalloid ions are recovered. When bead milling treatment is performed on HAp, the originally water-insoluble HAp obtains solubility in the amorphous part.

[0049] Embodiment 5 (Loading silver ions on amorphous β-TCP particles.) (1) Mix the powder of β-TCP particles and the powder of silver phosphate particles at a ratio of 0.99 - 0.9 to 0.01 - 0.1 by weight. Put the powder mixture together with a specified amount of acetone and grinding beads with a specified diameter into a zirconia container of a planetary ball mill device. Make the planetary ball mill device revolve and rotate at a certain speed, thereby crushing the β-TCP particles to reduce their particle size and increase their specific surface area. (2) Subjected to the impact of the grinding beads, part of the crystal structure of the β-TCP particles is amorphousized and part is ionized, and silver ions are separated from the silver phosphate particles. The separated silver ions are coordinated on the phosphate ions of the β-TCP particles. (3) After the high-speed rotation of the planetary ball mill device lasts for a certain time and then stands still, the state in which the silver ions separated from the metal salt particles are coordinately bonded to the phosphate ions of the amorphousized β-TCP particles is fixed. After the fixing process, the silver phosphate particles are separated from the above-mentioned powder mixture by sieving and rinsing, and the β-TCP particles containing silver ions are recovered.

[0050] The β-TCP particles whose crystal structure is partially amorphousized by bead milling treatment have higher solubility in body fluids than the β-TCP particles without bead milling treatment, and will be dissolved by body fluids and release calcium ions and phosphate ions as soon as possible. Moreover, the silver ions bonded to the amorphousized and ionized β-TCP particles will be released into the affected area in the body together with calcium ions and phosphate ions as the β-TCP particles dissolve to exert antibacterial properties.

[0051] Embodiment 6 (containing amorphousized β-TCP particles in biodegradable fibers) (1) Stir and mix β-TCP particles, amorphousized β-TCP particles and PDLLGA in acetone to prepare a particle dispersion. The weight ratio of β-TCP particles, amorphousized β-TCP particles and PDLLGA of 35%:35%:30% is taken as a representative example. (2) Use the prepared particle dispersion as a spinning dope and spin it into fibers with a fiber diameter of 100 - 150 μm by the wet spinning method. PDLLGA is amorphous and has a low intrinsic viscosity, so it is difficult to be spun by electrospinning to form a cotton-like shape. However, PDLLGA is more likely to come into contact with body fluids and be decomposed than PLLGA composed only of L-forms, so it is suitable for rapid bone formation.

[0052] When the bone regeneration material composed of PDLLGA resin fibers containing amorphousized β-TCP particles is implanted into the affected area, the PDLLGA resin will be dissolved as soon as possible. The amorphousized β-TCP particles contained in the PDLLGA resin fibers come into contact with body fluids and are dissolved as soon as possible, so that calcium ions and phosphate ions are released in the affected area as early as possible. Experiment 1

[0053] <Content of Experiment 1> (1) Add 40.5 g of grinding beads with a diameter of 1 mm and 13.5 g of acetone (= 17 ml) to the zirconia container (volume capacity 45 ml) of the planetary ball mill device. Immerse in the container in the state of adding grinding beads / acetone for 8 minutes. (2) Then, add β-TCP particles (Taihei Chemical Industry β-TCP-100, particle size 1 - 5 μm) in an amount with an apparent volume ratio to the grinding beads of 1:3 (the weight ratio of acetone to the total of β-TCP particles and grinding beads is 1:7.5). In this state, rotate the planetary ball mill device at a high speed with a revolution speed of 400 rpm and a rotation speed of 800 rpm. (3) Observe the obtained β-TCP particles (m-TCP particles) using SEM, and then measure the particle size (n = 200). In addition, measure the specific surface area of the particles by the nitrogen adsorption method, and conduct structure evaluation using XRD and TEM. In addition, immerse the m-TCP particles in tris-HCl buffer solution (37 °C, pH value 7.40), and study the ion dissolution behavior and particle changes using ICP-AES and XRD

[0054] <Results of Experiment 1> (i) Through bead milling treatment, the average diameter of β-TCP particles decreased to about 0.35 μm ( Figure 3 ), and the specific surface area was about 4.4 times (8.8 m 2 / g)( Figure 4 ). Since the medium is small to and the rotation speed is high, a large force is applied to the particles, and they are effectively crushed within a short time of 120 minutes. After treatment, separate the grinding beads from the slurry by sieving, dry the obtained slurry, and when rubbing between the thumb and index finger, no powder is felt on the fingertips. (ii) In the XRD pattern of the particles treated by bead milling, peaks attributed to β-TCP and broad peaks ( Figure 5 ) were observed. In the electron diffraction image of the particles, diffraction points attributed to β-TCP and a halo peak pattern ( Figure 11 ) were confirmed in the whole particles. (iii) In the tris-HCl buffer solution impregnated with the particles treated by bead milling, from the start of impregnation to 24 hours, a sharp increase in calcium ions and phosphate ions was found. In the XRD pattern of the particles after impregnation, a peak attributed to hydroxyapatite (HA) was newly found ( Figure 12 ). It is considered that due to the sharp increase in ion concentration, the supersaturation of the calcium phosphate phase increases, and HA precipitates. (vi) It can be known from experiments that by performing bead milling treatment, a part of the β-TCP particles can be amorphized in a short time, which can improve the solubility of the particles.

[0055] Comparative Experiment 1 Under the same conditions as in Experiment 1, the β-TCP particles were wet-milled using a planetary bead mill. However, an equal amount of water was used as the solvent for wet milling. As a result, when milling with water, it did not flow down immediately when separated by a sieve, but felt like it was wrapped around the bead part. When the obtained powder slurry was dried and rubbed between the thumb and index finger, the fingertips felt rough. According to the inventor's experience, in the case of feeling rough, it aggregates into a diameter of about 10 μm or more. In addition, from the XRD of the product obtained by milling with water, unlike the product obtained by milling with acetone, the peak of β-TCP remained, and a halo peak caused by the formation of an amorphous phase was observed at 25 - 40°, while for the product obtained by milling with water, the peak of β-TCP was not observed and only the peak of HA was observed. The halo peak was not confirmed ( Figure 13 ). It is considered that the calcium phosphate amorphized by milling reacted with water to form apatite.

[0056] Experiment 2 <Content of Experiment 2> (1) The β-TCP powder and Ag3PO4 powder were mixed at a weight ratio of 99 to 1 or 95 to 5 to prepare 1.8 g of the mixed powder. (2) 40.5 g of 1-mm-diameter beads and 13.5 g of acetone (= 17 ml) were added to a zirconia container (volume capacity 45 ml) of a planetary ball mill. It was immersed in the container in the state of adding beads / acetone for about 8 minutes. 1.8 g of the above-prepared mixed powder was put into it, and the ball mill was rotated at a high speed with a revolution of 400 rpm and a rotation of 800 rpm. (3) When the planetary ball mill was rotated at a high speed, the crystal structure of the β-TCP particles was partially amorphized by the impact of the beads. Due to the impact of the beads, Ag ions were separated from the Ag3PO4 particles, and the separated Ag ions (positive) were coordinated on the phosphate ions (negative) of the β-TCP particles. (4) After continuously rotating at a high speed for 2 hours and then standing still in the above planetary ball mill device, the state where the Ag ions separated from the Ag3PO4 particles were coordinately bonded to the phosphate ions of the amorphized β-TCP particles was fixed. (5) After the above fixing process, the Ag3PO4 particles were separated from the mixture of the above powder by sieving and rinsing, and the β-TCP particles containing silver ions were recovered.

[0057] <Results of Experiment 2> (i) The grinding beads used were 1 mm in diameter. For 1 mm beads, a sieve with an opening of about 125 μm was sufficient, and they could be roughly recovered by rinsing with acetone. If grinding beads with a diameter less than 1 mm were used, the pulverization effect would be enhanced, but since a sieve with a small opening that prevented the beads from falling was required, the recovery would take time. (ii) The particle powder prepared by wet bead milling of Ag3PO4 particles and β-TCP particles was immersed in a HEPES buffer solution (pH 7.40), and then the ion concentration of the solution was measured by ICP-AES to confirm the dissolution of Ag ions ( Figure 10 ).

[0058] Experiment 3 <Content of Experiment 3> (1) β-TCP powder (manufactured by Taihei Chemical Industry Co., Ltd.) and B2O3 powder (special grade, manufactured by Kishida Chemical Co., Ltd.) were mixed at a weight ratio of 10 - 30 to 90 - 70 to prepare 1.8 g of mixed powder. (2) 40.5 g of grinding beads with a diameter of 1 mm and 13.5 g of acetone (= 17 ml) were added to a zirconia container (volume capacity 45 ml) of a planetary ball mill device. They were immersed in the container in the state of adding grinding beads / acetone for about 8 minutes. 1.8 g of the above-prepared mixed powder was put into it, and the ball mill device was rotated at a high speed with a revolution of 400 rpm and a rotation of 800 rpm. (3) When the planetary ball mill device was rotated at a high speed, the crystal structure of β-TCP particles was partially amorphized by the impact of the grinding beads. At the same time, due to the impact of the grinding beads, strain or breakage occurred in some of the bonds of B2O3 particles, or new bonds were generated and they were amorphized. (4) After the high-speed rotation of the above planetary ball mill device continued for 2 hours and then it was left standing, it became a state where amorphous B2O3 particles were fused with the above-amorphized β-TCP. (5) After the above immobilization process, the treated material was separated by sieving and rinsing to recover calcium phosphate particles containing boron ions.

[0059] <Results of Experiment 3> (i) The size of the particles obtained by coexisting and pulverizing β-TCP powder and B2O3 powder was about 0.1 μm - 1 μm, and the shapes were various ( Figure 14 ). In addition, as the boron addition amount increased, the aggregated particles increased. It was considered that boron reacted with water in the atmosphere during the solid-liquid separation and drying processes and caused aggregation, and it was considered to be a powder with high reactivity to moisture. (ii) Elemental surface scanning by EDS ( Figure 15)It shows that B, Ca, and P are evenly distributed. Boron (B_Kα) is detected at a low energy position, so there are problems with accuracy, but it can be said to exist based on the spectral pattern judgment. Therefore, when surface scanning is performed, a state of distribution throughout the particles is observed, and it exists in the same parts as calcium (Ca_Kα) and phosphorus (P_Kα). Therefore, it is considered that boron is dispersed and incorporated into the prepared particles. (iii) In the XRD pattern of the obtained particles ( Figure 16 ), peaks attributable to β-TCP (●) and a halo peak caused by the amorphous phase are confirmed. It is considered that the introduction of boron does not hinder the amorphization of β-TCP achieved by mechanochemical treatment. Combining Figure 3 's results, it is considered that boron is also introduced into the amorphous phase. In addition, peaks attributable to boric acid (◇) are confirmed when 20% and 30% B2O3 are mixed. It is considered that boric acid is generated by the reaction of water in the atmosphere with boron oxide during the grinding process and during measurement. (iv) Figure 17 The 11B MAS-NMR spectrum of the obtained particles is shown. Boron shows the existence in the T structure (oxygen 3-coordination) and Q structure (oxygen 4-coordination). Figure 18 Shows 31 the P MAS-NMR spectrum. Due to the addition of boron, a peak related to the B-O-P bond is newly confirmed on the high magnetic field side (near -5 ppm). That is, through this mechanochemical treatment, boron is introduced into the amorphous phase together with calcium phosphate to form a chemical bond. (v) From the immersion test in tris-Hcl buffer solution ( Figure 19 ), it can be seen that the dissolution amount of borate ions depends to a large extent on the addition amount of boron. The ion concentration does not change after 6 hours of immersion, and all boron is dissolved in the initial stage of immersion. Without adding boron, the concentrations of calcium ions and phosphate ions dissolved in the initial stage decrease after 24 hours of immersion. According to the XRD pattern after immersion ( Figure 20 ), it is considered that this is due to the precipitation of HA. For the boron-containing samples, the ion concentration decreases rapidly, and it can be seen from the XRD pattern that the precipitation of HA is active. Borate glass (amorphous state) has low chemical durability, and the B-O network structure decomposes rapidly in the solution, and various ions are dissolved. As a result, the concentrations of calcium ions and phosphate ions increase, and the pH value also increases, so the precipitation of HA is likely to occur. The formation of HA in a simulated physiological environment is related to the excellent osteogenicity of the material, and an increase in its rate indicates its usefulness as a biomaterial containing B2O3.

[0060] Experiment 4 <Content of Experiment 4> (1) β-TCP powder (produced by Taihei Chemical Industry) and amorphous silica powder (SYLISIA, produced by Fuji Silicon Chemical) were mixed at a weight ratio of 95 to 90:5 to 10 to prepare 1.8 g of a mixed powder. (2) Add 40.5 g of grinding beads with a diameter of 1 mm and 13.5 g of acetone (=17 ml) into a zirconia container (volume capacity 45 ml) of a planetary ball mill. Immerse the container in the state of adding grinding beads / acetone for about 8 minutes. Add 1.8 g of the prepared mixed powder into the container, and rotate the ball mill at a high speed of 450 rpm for revolution and 820 rpm for rotation. (3) When the planetary ball mill is rotated at high speed, the crystal structure of the β-TCP particles is impacted by the grinding beads and partially amorphized. The silica raw material is an amorphous powder produced by the sol-gel method. (4) The planetary ball mill device was allowed to stand after high-speed rotation was continued for 2 hours, thereby achieving a state where the amorphous silica particles and the amorphized β-TCP were fused. (5) After the immobilization step, the treated product is separated by sieving and washing to recover the calcium phosphate particles containing phosphate ions.

[0061] <Results of Experiment 4> from Figure 21 The XRD spectrum of shows that even if silica is mixed, amorphization of β-TCP proceeds. The mixed silica is an amorphous powder produced by the sol-gel method, so it does not appear in the XRD spectrum. Depend on Figure 22 From the EDS surface scan results, it can be seen that silicon exists in approximately the same position as phosphorus and calcium. The spectra at points 1 to 5 do not differ much and are distributed throughout. The ion content of 50 mg of particles mixed with 5% silica was measured after immersion in 20 ml of tris-HCl buffer solution (37°C, pH 7.40) ( Figure 23 ), calcium ions and phosphate ions increased sharply after immersion for 1 hour and then gradually decreased. Figure 24 As can be seen from the XRD spectrum, HA is generated. Therefore, calcium ions and phosphate ions are consumed and reduced. On the other hand, silicon was found to be gradually dissolved over time, but the amount of dissolution seemed to gradually decrease after 24 hours. It is expected that this is because part of it is captured in the generated HA. Since silicate ions are known to have the effect of promoting bone formation, this dissolution behavior is preferred.

[0062] Experiment 5 <Contents of Experiment 5> The prepared bead-milled calcium phosphate particle powder (m-TCP) and particles of poly(D,L-lactic acid-gluconic acid) copolymer (PDLLGA) in Experiment 1 were mixed at a weight ratio of 70:30, and the mixture was put into an acetone solution and stirred for dispersion to prepare a spinning dope. The ratio of the powder amount to acetone was 1:6. The prepared spinning dope was filled into the spinning tube of a wet spinning device, and the filled spinning dope was extruded from the nozzle to produce biodegradable fibers (Fiber A) containing 30 wt% PDLLGA and 70 wt% calcium phosphate particles. In addition, for comparison, fibers (Fiber B) with a weight ratio of β-TCP:m-TCP:PDLLGA of 35:35:30 and fibers (Fiber C) with a weight ratio of β-TCP:PDLLGA of 70:30 without m-TCP were produced by the same method as above. However, the ratio of the powder amount to acetone was 1:5. <Results of Experiment 5> (i) Since the m-TCP particle powder does not agglomerate, a spinning dope with particles dispersed in a liquid can be easily prepared by putting the powder and the resin into a solvent and stirring. (ii) On the other hand, to produce fibers (Fiber B) containing both β-TCP and m-TCP, since their particle sizes are different, it is necessary to prevent the sedimentation of the larger-sized β-TCP as much as possible. Therefore, fibers with relatively good particle dispersion can be obtained by preparing a spinning dope with increased viscosity. The same is true in the case of only β-TCP being dispersed (Fiber C), and fibers with relatively good particle dispersion can be obtained by preparing a spinning dope with increased viscosity (the ratio of the powder amount to acetone is 1:5). (iii) The ion amounts after immersing Fibers A, B, and C in 20 ml of tris-HCl buffer solution (37 °C, pH 7.40) were measured ( Figure 25 ), and after 6 hours of immersion, Fibers A and B dissolved 6 to 7 times more calcium ions and phosphate ions than Fiber C. It is considered that this is because the amorphous phase dissolves in m-TCP. The amounts of each ion in Fiber A decreased after 72 hours of immersion. The formation of HA was confirmed by XRD ( Figure 26 ). Therefore, it can be said that the calcium ions and phosphate ions decreased due to being consumed. These results show that by using m-TCP as the biodegradable fiber, a positive function of dissolving calcium ions and phosphate ions is imparted.

[0063] The present invention has been described based on the embodiments of the present invention, but the scope of the present invention is not limited to these embodiments and should be limited only to the description in the claims of this application.

Claims

1. A method for wet - grinding crystalline calcium phosphate particles using a bead - mill device to modify them into amorphous calcium phosphate, wherein, In the container of the bead mill device, a powder of crystalline calcium phosphate particles with a diameter of 1 to 5 μm and grinding beads with a median diameter of 0.015 to 2.0 mm are introduced in an amount such that the apparent volume ratio of the former to the latter is 1:2 to 4. For the mixture of the crystalline calcium phosphate particle powder and the grinding beads in the container, acetone is introduced in an amount such that the weight ratio of the former to the latter is 1:5 to 10 and stirred to prepare a slurry containing the calcium phosphate particles and the grinding beads in the acetone. With the slurry contained in the container, the bead mill device is rotated at a specified number of revolutions per minute for a specified time. Thereby, the powder of the calcium phosphate particles contained in the slurry is pulverized to a particle size of 0.1 to 1.2 μm without causing agglomeration, and the crystalline calcium phosphate particles are partially amorphized and the crystallinity is reduced to 50 to 10% by being impacted by the grinding beads.

2. The method according to claim 1, wherein, The bead mill device uses a planetary device having a self-rotation and revolution function.

3. The method according to claim 1 or 2, wherein, The crystalline calcium phosphate particles are β-TCP or HAp.

4. The method according to claim 1 or 2, wherein, The metal salt is silver phosphate.

5. The method according to claim 1 or 2, wherein, The semi-metal salt is a silicate or a borate.

6. The method according to claim 1 or 2, wherein, The powder of the crystalline calcium phosphate particles is mixed with the powder of metal salt particles or semi-metal salt particles at a ratio of 0.99 to 0.9 to 0.01 to 0.1 by weight. The powder mixture is introduced into the container of the planetary bead mill device together with a specified amount of acetone and grinding beads, and the planetary bead mill device is rotated at a high speed at a specified number of revolutions per minute. Thereby, metal ions or semi-metal ions separated from the metal salt particles or semi-metal salt particles are coordinated to the phosphate ions of the amorphized calcium phosphate particles.

7. A calcium phosphate particle which is a calcium phosphate particle carrying metal ions or metalloid ions in a sustained - release manner, wherein, The crystal structure of the crystalline calcium phosphate particles is partially modified to an amorphous state by performing a bead mill treatment on the calcium phosphate particles. By coordinating metal or semi-metal ions to the phosphate ions of the amorphized portion of the crystalline calcium phosphate particles, the metal or semi-metal ions are supported on the calcium phosphate particles in a manner capable of sustained release. When the calcium phosphate particles carrying the metal or semi-metal ions are implanted into a living body and come into contact with body fluid, the amorphized calcium phosphate particles are dissolved, and the metal or semi-metal ions are released together with calcium ions and phosphate ions.

8. The calcium phosphate particle according to claim 7, wherein, The bead mill treatment uses a planetary device having a self-rotation and revolution function.

9. The calcium phosphate particle according to claim 7 or 8, wherein, The crystalline calcium phosphate particles are β-TCP or HAp.

10. The calcium phosphate particle according to claim 7 or 8, wherein, The metal salt is silver phosphate.

11. The calcium phosphate particle according to claim 7 or 8, wherein, The semi-metal salt is a silicate or a borate.

12. A method for manufacturing a bone - regenerating material, which is a method for manufacturing a bone - regenerating material composed of biodegradable fibers containing calcium phosphate particles modified into an amorphous state, and the manufacturing method includes the following steps: In a container of a bead - mill device, a powder of crystalline calcium phosphate particles with a diameter of 1 - 5 μm and grinding beads with a median diameter of 0.015 - 2.0 mm are put in an amount such that the apparent volume ratio of the former to the latter is 1:2 - 4. For the mixture of the crystalline calcium phosphate particle powder and the grinding beads in the container, acetone is put in an amount such that the weight ratio of the former to the latter is 1:5 - 10 and stirred, thereby preparing a slurry containing the calcium phosphate particles and the grinding beads in the acetone. With the slurry contained in the container, rotate the bead mill device at a specified rotational speed per minute for a specified time, whereby the powder of the crystalline calcium phosphate particles contained in the slurry is pulverized to a particle size of 0.1 to 1.2 μm without causing them to aggregate, and the crystalline calcium phosphate particles are partially amorphized by the impact from the grinding beads and the crystallinity is reduced to 50 to 10%. Put the powder of the amorphized calcium phosphate particles together with the biodegradable resin into a solvent and stir, thereby preparing a spinning dope in which the amorphized calcium phosphate particles are dispersed. Fill the spinning dope into the spinning tube of the spinning device and extrude it from the nozzle for spinning, and stack the obtained biodegradable fibers on a collector for recovery.

13. The method for manufacturing a bone regeneration material according to claim 12, wherein The bead mill device uses a planetary device having a self-rotation and revolution function.

14. The method for manufacturing a bone regeneration material according to claim 12 or 13, wherein The crystalline calcium phosphate particles are β-TCP or HAp.

15. The method for manufacturing a bone regeneration material according to claim 12 or 13, wherein Metal or semi-metal ions are bonded to the calcium phosphate particles modified to an amorphous state.

16. A bone regeneration material comprising biodegradable fibers containing calcium phosphate particles modified to an amorphous state, and the bone regeneration material is manufactured by a method including the following steps: In the container of the bead mill device, put the powder of crystalline calcium phosphate particles with a diameter of 1 to 5 μm and grinding beads with a median diameter of 0.015 to 2.0 mm in an amount such that the apparent volume ratio of the former to the latter is 1:2 to 4. For the mixture of the crystalline calcium phosphate particle powder and the grinding beads in the container, put acetone in an amount such that the weight ratio of the former to the latter is 1:5 to 10 and stir, thereby preparing a slurry containing the calcium phosphate particles and the grinding beads in the acetone. With the slurry contained in the container, rotate the bead mill device at a specified rotational speed per minute for a specified time, whereby the powder of the crystalline calcium phosphate particles contained in the slurry is pulverized to a particle size of 0.1 to 1.2 μm without causing them to aggregate, and the crystalline calcium phosphate particles are partially amorphized by the impact from the grinding beads and the crystallinity is reduced to 50 to 10%. Put the powder of the amorphized calcium phosphate particles together with the biodegradable resin into a solvent and stir, thereby preparing a spinning dope in which the amorphized calcium phosphate particles are dispersed. Fill the spinning dope into the spinning tube of the spinning device and extrude it from the nozzle for spinning, and stack the obtained biodegradable fibers on a collector for recovery.

17. The bone regeneration material according to claim 16, wherein, The bead mill device uses a planetary device having a self-rotation and revolution function.

18. The bone regeneration material according to claim 16 or 17, wherein, Metal or semi-metal ions are supported on the calcium phosphate particles modified to an amorphous state in a manner capable of sustained release.

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