Ceramic slurry for light-cured forming of artificial bone scaffold and preparation method thereof

Abstract

The application discloses a ceramic slurry for light-cured forming of artificial bone scaffolds and a preparation method thereof. The ceramic slurry comprises the following components: resin premix liquid 40-60 parts by volume; hydroxylated ceramic powder 40-65 parts by volume; and a dispersant, wherein the addition amount of the dispersant is 1.5-20 wt% of the mass of the ceramic powder. The hydroxylated ceramic powder comprises hydroxylated hydroxyapatite (HA), beta-tricalcium phosphate (beta-TCP) and biologically inert ceramic, and the mass ratio of the HA, beta-TCP and biologically inert ceramic is 4-7:1-3:1-4. The resin premix liquid comprises photosensitive resin monomer, plasticizer and photoinitiator, and the mass ratio of the photosensitive resin monomer and the plasticizer is 3-21:1-2. The mass percentage of the photoinitiator in the resin premix liquid is 0.5-2 wt%.

Description

Technical Field

[0001] This invention relates to the field of ceramic photopolymer additive manufacturing technology, and in particular to a ceramic slurry for photopolymer molding of artificial bone scaffolds and its preparation method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Bone defects are a serious bone injury that severely threatens health. When large segments of bone are missing, appropriate bone implants are needed to fill the damaged areas to aid in treatment. Among clinical implants, autologous bone grafts have limited availability, while allogeneic bone grafts are prone to rejection. Porous bioactive scaffolds have emerged as an effective solution as bone substitutes, utilizing artificial bone implant materials that are widely available and biocompatible.

[0004] Bioceramic materials are broadly classified into two categories: inert ceramics and bioactive ceramics. Inert bioceramics are materials that maintain stable physicochemical properties in the body environment over a long period, exhibiting minimal degradation. They possess high strength and good stability but poor osteogenic properties; these include Al₂O₃ ceramics and ZrO₂ ceramics. Bioactive ceramics, on the other hand, are ceramics that can form chemical bonds with host bone, achieving bone guidance after implantation. They are far superior to inert ceramics in terms of osteogenic properties and are biodegradable and absorbable by human tissues. However, their disadvantages include low flexural strength and high brittleness. These mainly include β-tricalcium phosphate (β-TCP), hydroxyapatite (HA), and bioactive glass (BG).

[0005] Because the solid content of photocurable bioceramic slurry is low, the formed bone scaffold will deform, shrink, delaminate, or even crack after degreasing and sintering due to the lack of resin components, making it difficult to meet the requirements for repairing bone tissue defects. However, as the solid content increases, the viscosity of the slurry will also increase, making it impossible for the slurry to achieve good coating and self-leveling during printing, thus causing defects in the printed blank. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a ceramic slurry for photocuring artificial bone scaffolds and its preparation method.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] In a first aspect, the present invention provides a ceramic slurry for photocuring artificial bone scaffolds, comprising the following components: 40-60 parts by volume of resin premix; 35-65 parts by volume of hydroxylated ceramic powder; and an amount of dispersant added at 1.5-20 wt% of the ceramic powder mass.

[0009] The hydroxylated ceramic powder includes hydroxylated hydroxyapatite (HA), β-calcium triphosphate (β-TCP), and bio-inert ceramics, with a mass ratio of HA, β-TCP, and bio-inert ceramics of 4–7:1–3:1–4.

[0010] The resin premix comprises photosensitive resin monomer, plasticizer, and photoinitiator. The mass ratio of photosensitive resin monomer to plasticizer is 3–21:1–2. The photoinitiator accounts for 0.5–2 wt% of the resin premix.

[0011] In some embodiments, the bio-inert ceramic is Al2O3 or ZrO2.

[0012] Preferably, the bio-inert ceramic is Al2O3.

[0013] Further preferred, the average particle size D of the HA particles 50 The average particle size D of β-TCP particles is 2.5–6.5 μm. 50 The average particle size D of Al2O3 particles is 1.2–2.5 μm. 50 The range is 100–600 nm.

[0014] More preferably, the Al2O3 is spherical. Due to its symmetrical geometry, spherical particles can provide better flowability and dispersibility in the slurry, helping to reduce interparticle friction and agglomeration, thereby reducing the viscosity of the slurry; on the other hand, spherical particles can be packed more tightly, thus achieving a higher packing density.

[0015] In some embodiments, the photosensitive resin monomer is selected from one or more of monofunctional photosensitive resin monomers, difunctional photosensitive resin monomers, or trifunctional photosensitive resin monomers.

[0016] Preferably, the monofunctional photosensitive resin monomer is acrylamide morpholine (ACMO), isobornyl acrylate (IBOA), or hydroxyethyl methacrylate (HEMA).

[0017] Alternatively, the bifunctional photosensitive resin monomer is 1,6-hexanediol diacrylate (HDDA), propoxylated neopentyl glycol diacrylate (PONPGDA), or polyethylene glycol diacrylate (PEGDPA).

[0018] Alternatively, the trifunctional photosensitive resin monomer is ethoxylated trimethylolpropane triacrylate (EO3TMPTA) or trimethylolpropane triacrylate (TMPTA).

[0019] More preferably, the photosensitive resin monomer is a mixture of monofunctional photosensitive resin monomer, difunctional photosensitive resin monomer and trifunctional photosensitive resin monomer; the mass ratio of monofunctional photosensitive resin monomer, difunctional photosensitive resin monomer and trifunctional photosensitive resin monomer is 1-7:1-7:1-7.

[0020] More preferably, the mass ratio of ACMO, HDDA and EO3TMPTA in the photosensitive resin monomer is 1-7:1-7:1-7.

[0021] In some embodiments, the plasticizer is dibutyl phthalate (DBP) and / or 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB).

[0022] In some embodiments, the photoinitiator is bis(2,4,6-trimethylbenzoyl)diphenylphosphine oxide (BAPO) or / and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO).

[0023] Preferably, the photoinitiator is bis(2,4,6-trimethylbenzoyl)diphenylphosphine oxide (BAPO).

[0024] In some embodiments, the dispersant is selected from one or two of the following: ammonium polyacrylate PAA-NH4, silane coupling agent KH550, silane coupling agent KH560, silane coupling agent KH570, Solsperse 41000, Solsperse 20000, KOS110, BYK111, or BYK333.

[0025] Preferably, the dispersant is a mixture of KH570 and KOS110, with a mass ratio of KH570 to KOS110 of 0.8–1.2:0.8–1.2.

[0026] Preferably, the dispersant is KOS110.

[0027] Secondly, the present invention provides a method for preparing the ceramic slurry for photocuring artificial bone scaffolds, comprising the following steps:

[0028] The photosensitive resin monomer, plasticizer and photoinitiator are mixed in proportion to obtain a resin premix;

[0029] The mixed ceramic powder of HA, β-TCP and bio-inert ceramics was soaked in NaOH solution for 15-30 hours, then washed and dried. The mixed ceramic powder and H2O2 solution were mixed at a volume ratio of 1:1.5-3 and stirred for 20-40 minutes to carry out surface modification. After the modification was completed, the H2O2 solution was removed, and the powder was dried, ground and sieved to obtain the surface hydroxylated modified ceramic powder.

[0030] The ceramic slurry is obtained by vacuum mixing the resin premix, dispersant, and surface hydroxylated modified ceramic powder in a certain proportion.

[0031] The purpose of vacuum mixing is to obtain a bubble-free, homogeneous ceramic slurry.

[0032] In some embodiments, the vacuum mixing time is 10 to 15 minutes.

[0033] In some embodiments, the concentration of the NaOH solution is 0.3-0.8 mol / L, and the soaking time is 20-25 h.

[0034] In some embodiments, the mass concentration of the H2O2 solution is 25%-35%.

[0035] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0036] This invention introduces coarse β-TCP particles and fine Al2O3 filler into HA ceramic slurry. The coarse β-TCP particles are used to fill the voids between HA ceramic particles and increase the solid content of the ceramic slurry; the fine Al2O3 particles are used to reduce the flow resistance of irregular HA / β-TCP particles in the slurry.

[0037] Furthermore, the pre-treatment of ceramic particles with surface hydroxylation in this invention increases the contact sites between the ceramic particles and the surface modifier. Further surface grafting of the hydroxylated ceramic particles with a dispersant improves the compatibility and dispersion stability of the ceramic particles in the resin. The preparation method provided by this invention can produce slurries of various bioceramic materials that possess high solid content, low viscosity, and good rheological and dispersion stability. Attached Figure Description

[0038] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0039] Figure 1 This is a flowchart of the slurry preparation process according to an embodiment of the present invention.

[0040] Figure 2 Various ceramic slurries are provided for embodiments of the present invention.

[0041] Figure 3 The viscosity curve is for the 50 vol% ceramic slurry of Example 1.

[0042] Figure 4 Viscosity curves of ceramic slurries prepared for Examples 2, 1, 2, 3 and 4 of the present invention.

[0043] Figure 5 This invention describes a three-period minimal surface structure printed using a 50 vol% multi-ceramic paste.

[0044] Figure 6 Fourier transform infrared spectrum of HA powder modified with KH570+KOS110 bidispersant. Detailed Implementation

[0045] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0046] The present invention will be further described below with reference to the embodiments.

[0047] Example 1

[0048] A ceramic slurry for photocuring artificial bone scaffolds comprises 50 parts by volume of a resin premix, 50 parts by volume of hydroxylated ceramic powder, and dispersants KH570+KOS110 (added at 16 wt% of the ceramic powder mass, with a mass ratio of 1:1 between the two dispersants). The resin premix contains photosensitive resin ACMO, HDDA, EO3TMPTA, and plasticizer TXIB in a mass ratio of 7:1:1:1, and the photoinitiator BAPO is added at 1.5 wt% of the photosensitive resin monomer mass. The ceramic powder comprises 70 wt% HA (D50 = 3.25 μm), 20 wt% β-TCP (D50 = 1.2 μm), and 10 wt% spherical Al2O3 (D50 = 500 nm).

[0049] The method for preparing the ceramic slurry for photocuring artificial bone scaffolds includes the following steps:

[0050] Step 1: Based on the D-optimal mixing experimental design method, ACMO, HDDA, EO3TMPTA and TXIB were prepared into a resin premix in proportion. After adding the photoinitiator, the resin premix was mixed evenly by magnetic stirring at 35℃ and 550rpm for 30 minutes until the premix was clear.

[0051] Step 2: Measure the viscosity of each group of resin premix and the performance parameters of the printed parts after printing. Use the viscosity of each group of resin premix, the tensile strength of the printed tensile specimen, and the curing shrinkage rate as response variables to establish a response surface model and obtain the proportion of resin premix with the best overall performance. The mass ratio of ACMO, HDDA, EO3TMPTA, and TXIB is 7:1:1:1.

[0052] A 5×4×36mm cuboid model was designed according to GB / T 9341-2008 to determine the curing shrinkage rate and flexural strength. The curing shrinkage rate of the resin was calculated using the following formula.

[0053]

[0054] Where, ρ s It is the density of the cured resin, measured using Archimedes' method of water displacement, ρ l This is the density of the uncured resin, tested using the specific gravity bottle method.

[0055] Step 3: Soak the ceramic powder in 0.5 mol / L NaOH solution for 24 h, wash and cool it, then pass the ceramic powder through a 100-mesh sieve. Then add the powder and 30% mass fraction H2O2 solution in a 1:2 volume ratio to a beaker, stir magnetically for 30 min, and then put it into a drying oven to dry at 100℃ for 6 h to obtain powder. Grind and crush the powder and pass it through a 120-mesh sieve to obtain uniform ceramic powder with surface hydroxylation.

[0056] Step 4: Transfer the resin premix obtained in Step 2, organic dispersant KH570+KOS110 and the uniform powder obtained in Step 3 into a vacuum defoaming homogenizer. The speed of the vacuum defoaming homogenizer is 2000 r / min. Mix for 10 min at room temperature under vacuum to obtain a foam-free homogenized ceramic slurry.

[0057] Example 2

[0058] The difference from Example 1 is that the volume fraction of ceramic powder in the ceramic slurry used for photocuring artificial bone scaffolds is 35 parts.

[0059] Example 3

[0060] A ceramic slurry for photocuring artificial bone scaffolds comprises 60 parts by volume of a resin premix, 40 parts by volume of hydroxylated ceramic powder, and dispersants KH570+KOS110 (added at 16 wt% of the ceramic powder mass, with a mass ratio of 1:1 between the two dispersants). The mass ratio of photosensitive resin ACMO, HDDA, EO3TMPTA, and plasticizer TXIB in the resin premix is ​​3:2:4:1, and the amount of photoinitiator BAPO added is 2 wt% of the photosensitive resin monomer mass. The ceramic powder comprises 60 wt% HA (D50 = 4.25 μm), 25 wt% β-TCP (D50 = 2 μm), and 15 wt% spherical Al2O3 (D50 = 400 nm).

[0061] Comparative Example 1

[0062] The difference from Example 2 is that the ceramic powder is not subjected to surface hydroxylation treatment.

[0063] Comparative Example 2

[0064] The only difference from Comparative Example 1 is that the dispersant used is KOS110, and the amount added is 7 wt% of the ceramic powder mass.

[0065] Comparative Example 3

[0066] The only difference from Comparative Example 1 is that the dispersant used is Solsperse 41000, and the amount added is 16 wt% of the ceramic powder mass.

[0067] Comparative Example 4

[0068] The only difference from Comparative Example 1 is that the dispersant used is KOS110+Solsperse41000, the amount added is 16wt% of the ceramic powder mass, and the mass ratio of the two dispersants is 1:1.

[0069] Viscosity curves of ceramic slurries prepared in Examples 2, 1, 2, 3, and 4 are shown below. Figure 4 As shown, the didispersant KH570+KOS110 is more effective than the monodispersants KOS110, Solsperse41000 and the didispersant KOS110+Solsperse41000 in improving slurry viscosity.

[0070] Furthermore, after surface hydroxylation of the particles, surface grafting was performed using the dual dispersants KH570+KOS110, which further reduced the viscosity of the slurry. Fourier transform infrared spectroscopy (FTIR) results of dispersants KOS110, KH570, raw hydroxyapatite powder, and hydroxyapatite particles treated with KH570+KOS110 are shown below. Figure 6 As shown. The C=O stretching vibration peak (1720 cm⁻¹) of KH570-modified hydroxyapatite powder after KOS110 modification is observed. -1 When the carboxylic acid group of KOS110 is substituted, the stretching vibration peak shifts to 1734 cm⁻¹. -1 CH stretching vibrations (2944 cm⁻¹) were observed on the particles modified with the bidispersant. -1 This indicates that the hydrophobic methyl groups of KH570 and KOS110 are transferred to the hydroxyapatite particles via physical adsorption. The dual methyl groups increase the compatibility between the ceramic particles and the resin, which is beneficial for the uniform dispersion of the particles in the resin. (3370~3560cm) -1The broad peaks within this range are related to the stretching vibrations of free hydroxyl (OH) groups. The weakening of these peaks indicates that after KH570-modified hydroxyapatite powder is modified by KOS110, the number of free hydroxyl groups on the particle surface decreases, leading to a reduction in the interaction energy between particles. This helps to reduce the attractive force between particles, thereby reducing particle aggregation. Coarse β-TCP particles and fine Al2O3 fillers are introduced into the HA ceramic slurry. The coarse β-TCP particles fill the voids between HA ceramic particles, increasing the solid content of the ceramic slurry; the fine Al2O3 particles reduce the flow resistance of irregular HA / β-TCP particles in the slurry.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A ceramic slurry for photocuring artificial bone scaffolds, characterized in that: The product comprises the following components: 40-60 parts by volume of resin premix; 35-65 parts by volume of hydroxylated ceramic powder; and a dispersant added at a rate of 1.5-20 wt% of the ceramic powder mass. The hydroxylated ceramic powder includes hydroxylated hydroxyapatite, β-triphosphate, and bio-inert ceramics, with a mass ratio of HA, β-TCP, and bio-inert ceramics of 4~7:1~3:1~4. The resin premix comprises photosensitive resin monomer, plasticizer, and photoinitiator, with a mass ratio of photosensitive resin monomer to plasticizer of 3~21:1~2; the photoinitiator accounts for 0.5~2 wt% of the resin premix. The bio-inert ceramic is Al2O3; the Al2O3 is spherical in shape; The average particle size D of the HA particles 50 The average particle size D of β-TCP particles is 2.5–6.5 μm. 50 The average particle size D of Al2O3 particles is 1.2~2.5μm. 50 The range is 100~600nm; The dispersant is a mixture of KH570 and KOS110, with a mass ratio of KH570 to KOS110 of 0.8~1.2:0.8~1.

2.

2. The ceramic slurry for photocuring artificial bone scaffolds according to claim 1, characterized in that: The photosensitive resin monomer is selected from one or more of the following: monofunctional photosensitive resin monomers, difunctional photosensitive resin monomers, or trifunctional photosensitive resin monomers.

3. The ceramic slurry for photocuring artificial bone scaffolds according to claim 2, characterized in that: The monofunctional photosensitive resin monomer is acryloylmorpholine, isobornyl acrylate, or hydroxyethyl methacrylate.

4. The ceramic slurry for photocuring artificial bone scaffolds according to claim 2, characterized in that: The bifunctional photosensitive resin monomer is 1,6-hexanediol diacrylate, propoxylated neopentyl glycol diacrylate, or polyethylene glycol diacrylate.

5. The ceramic slurry for photocuring artificial bone scaffolds according to claim 2, characterized in that: The trifunctional photosensitive resin monomer is ethoxylated trimethylolpropane triacrylate or trimethylolpropane triacrylate.

6. The ceramic slurry for photocuring artificial bone scaffolds according to claim 2, characterized in that: The photosensitive resin monomer is a mixture of monofunctional photosensitive resin monomer, difunctional photosensitive resin monomer and trifunctional photosensitive resin monomer; the mass ratio of monofunctional photosensitive resin monomer, difunctional photosensitive resin monomer and trifunctional photosensitive resin monomer is 1~7:1~7:1~7.

7. The ceramic slurry for photocuring artificial bone scaffolds according to claim 6, characterized in that: The mass ratio of ACMO, HDDA and EO3TMPTA in the photosensitive resin monomer is 1~7:1~7:1~7.

8. The ceramic slurry for photocuring artificial bone scaffolds according to claim 1, characterized in that: The plasticizer is dibutyl phthalate or / and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate.

9. The ceramic slurry for photocuring artificial bone scaffolds according to claim 1, characterized in that: The photoinitiator is bis(2,4,6-trimethylbenzoyl)diphenylphosphine oxide or / and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide.

10. The ceramic slurry for photocuring artificial bone scaffolds according to claim 9, characterized in that: The photoinitiator is bis(2,4,6-trimethylbenzoyl)diphenylphosphine oxide.

11. The method for preparing the ceramic slurry for photocuring artificial bone scaffolds according to any one of claims 1-10, characterized in that: Includes the following steps: The photosensitive resin monomer, plasticizer and photoinitiator are mixed in proportion to obtain a resin premix; The mixed ceramic powder of HA, β-TCP and bio-inert ceramics was soaked in NaOH solution for 15-30h, then washed and dried. The mixed ceramic powder and H2O2 solution were mixed at a volume ratio of 1:1.5-3 and stirred for 20-40min to carry out surface modification. After the modification was completed, the H2O2 solution was removed and dried to obtain the surface hydroxylated modified ceramic powder. The ceramic slurry is obtained by vacuum mixing the resin premix, dispersant, and surface hydroxylated modified ceramic powder in a certain proportion.

12. The method for preparing ceramic slurry for photocuring artificial bone scaffolds according to claim 11, characterized in that: The vacuum mixing time is 10-15 minutes.

13. The method for preparing the ceramic slurry for photocuring artificial bone scaffolds according to claim 11, characterized in that: The concentration of the NaOH solution is 0.3-0.8 mol / L, and the soaking time is 20-25 h.

14. The method for preparing ceramic slurry for photocuring artificial bone scaffolds according to claim 11, characterized in that: The mass concentration of the H2O2 solution is 25%-35%.

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