A method for preparing and using strontium-doped magnesium-bioactive glass

Abstract

The present application relates to the technical field of bioactive glass, in particular to a preparation method and application of strontium-magnesium-doped bioactive glass, on the basis of selecting suitable raw materials, the co-precipitation method is adopted, strontium element is doped, and magnesium oxide is compoundedly added, so that the prepared bioactive glass has regular properties, good dispersible spherical particles, faster and stronger hydroxyapatite formation capacity, faster ion release rate, and can release calcium, phosphorus and silicon ions in simulated body fluid, form more hydroxyapatite, promote the proliferation and stability of bone cells, and stimulate new bone formation. The strontium-magnesium-doped bioactive glass is used in cooperation with mineral trioxide aggregate (MTA), so that cell adhesion, expression of bioactive enzymes, activity of fibroblasts can be promoted, and the strontium-magnesium-doped bioactive glass can be applied to the repair of human bone and dental pulp tissue.

Description

Technical Field

[0001] This invention relates to the field of bioactive glass technology, specifically to a method for preparing and applying strontium-magnesium-doped bioactive glass. Background Technology

[0002] Bioactive glass (BGs) is a silicate material primarily composed of SiO2, Na2O, CaO, and P2O5. The ionic products generated after the dissolution of bioactive glass can directly influence the gene expression profile of human osteoblasts, initially leading to its use in bone repair and regeneration. Simultaneously, bioactive glass has also shown significant effectiveness in preventing demineralization of dental hard tissues. Traditionally, bioactive glass prepared using the fusion and sol-gel methods is widely used clinically. However, these methods have inherent limitations, such as high energy consumption during high-temperature melting, the potential for corrosion and contamination due to the destruction of alkaline components at high temperatures, and the difficulty in dispersing sol-gel bioactive glass due to its agglomerated state, requiring grinding and sieving, resulting in irregular particle morphology and uneven particle size, thus limiting its application in dental restoration.

[0003] Zinc (Zn), zirconium (Zr), magnesium (Mg), and strontium (Sr) are the main trace elements that play a crucial role in the development, maintenance, and repair of human bones by stimulating osteocytes. They also have anti-caries and bone-strengthening effects. A certain amount of strontium can promote osteocyte proliferation and differentiation, while simultaneously inhibiting osteoclast formation to prevent bone resorption, thereby promoting new bone growth. Therefore, incorporating trace elements into the preparation of bioactive glass for better application in the repair of tooth defects is a feasible direction for bioactive glass research.

[0004] For example, Chinese patent number CN101407373B discloses a strontium-reinforced bioactive glass, its preparation method and its application in dental cleaning products, and Chinese application number CN112079572A discloses a method for preparing strontium-doped hollow bioactive glass microspheres and the product obtained therefrom. However, the above patented technologies do not significantly improve the preparation method. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing strontium-magnesium-doped bioactive glass and its application. The bioactive glass prepared by this method has well-dispersed spherical particles and a faster and stronger ability to form hydroxyapatite, effectively promoting the proliferation and stability of osteocytes and stimulating new bone formation.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for preparing strontium-magnesium-doped bioactive glass, comprising the following steps:

[0008] Step (1) Take 28.8 mL of deionized water into a beaker, adjust the pH of the solution to 1.5 with 0.5 M hydrochloric acid, and add 2.32 g of surfactant;

[0009] Step (2) Stir the solution from step (1) at 38-42℃ until it is homogeneous and transparent. Add 7.3 mL of tetraethyl orthosilicate, 0.55 mL of triethyl phosphate and 1.53 g of calcium nitrate tetrahydrate in sequence. Stir for 25-30 min. Then add 2.36 g of strontium acetate and 0.46 g of magnesium oxide. Continue stirring for 20-30 h. Pour the mixture into a high-pressure reactor and react at 150-200℃ and 1-5 MPa pressure for 2.5-3.5 h. Cool the mixture and remove it to dry it.

[0010] Step (3) Reflux the precipitate obtained in step (2) in anhydrous ethanol at 65-75℃ for 10-15h, then centrifuge at 4500-5500r / min for 10-15min, and then continue to dry the precipitate at 55-65℃ for 20-30h.

[0011] Step (4) Place the dried product in a muffle furnace and heat it to 750-850℃ at a heating rate of 2℃ / min for 2.5-3.5h to obtain strontium-magnesium-doped bioactive glass.

[0012] Preferably, the surfactant in step (1) is surfactant P123, namely, a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer.

[0013] Preferably, in step (2), after the high-pressure reactor has completed the reaction, it is cooled to room temperature at a rate of 3-5°C.

[0014] Preferably, in step (2), the drying process involves heat treatment in an oven at 95-105°C for 20-30 hours, followed by drying the reaction product at 55-65°C.

[0015] Preferably, the chemical composition of the strontium-magnesium-doped bioactive glass is 60% SiO2, 25% CaO, 6% SrO, 5% MgO, and 4% P2O5 (molar percentage).

[0016] An application of strontium-magnesium-doped bioactive glass: applying strontium-magnesium-doped bioactive glass to the repair of human bone and dental pulp tissues.

[0017] An application of strontium-magnesium-doped bioactive glass involves preparing a hydration gel by mixing strontium-magnesium-doped bioactive glass with mineral trioxide aggregates (MTA) at a mass ratio of 1:4.

[0018] An application of strontium-magnesium-doped bioactive glass involves preparing a hydration gel by combining strontium-magnesium-doped bioactive glass with mineral trioxide aggregates (MTA) at a mass ratio of 1:4, and applying it to the repair of human bone and dental pulp tissues.

[0019] The beneficial effects of this invention are as follows: Based on the selection of suitable raw materials, this invention employs a co-precipitation method, incorporating strontium and magnesium oxide simultaneously. The resulting bioactive glass not only exhibits relatively regular morphology and well-dispersible spherical particles, but also possesses a faster and stronger ability to form hydroxyapatite, thus exhibiting a faster ion release rate. Immersion in simulated body fluids allows it to release calcium, phosphorus, and silicon ions, forming more hydroxyapatite, promoting osteocyte proliferation and stability, and stimulating new bone formation. The strontium-magnesium-doped bioactive glass, when used in conjunction with mineral trioxide aggregates (MTA), can promote cell adhesion, enhance the expression of bioactive enzymes, and increase fibroblast activity, making it suitable for the repair of human bone and dental pulp tissues. Attached Figure Description

[0020] Figure 1 These are scanning electron microscope images of the bioactive glass of this invention;

[0021] Figure 2 These are scanning electron microscope images of the in vitro hydroxyapatite formation experiment of this invention;

[0022] Figure 3 This is a graph showing the proliferation activity of the cell compatibility experiment of the present invention. Detailed Implementation

[0023] The present invention will be further described in conjunction with the following embodiments.

[0024] Example 1.

[0025] A method for preparing strontium-magnesium-doped bioactive glass, comprising the following steps:

[0026] Step (1) Take 28.8 mL of deionized water into a beaker, adjust the pH of the solution to 1.5 with 0.5 M hydrochloric acid, and add 2.32 g of surfactant;

[0027] Step (2) Stir the solution from step (1) at 38°C until it is homogeneous and transparent. Add 7.3 mL of tetraethyl orthosilicate, 0.55 mL of triethyl phosphate and 1.53 g of calcium nitrate tetrahydrate in sequence. Stir for 25 min. Then add 2.36 g of strontium acetate and 0.46 g of magnesium oxide. Continue stirring for 20 h. Pour the mixture into a high-pressure reactor and react at 150°C and 2.5 MPa pressure for 2.5 h. Cool the mixture and remove it to dry it.

[0028] Step (3) The precipitate obtained in step (2) is refluxed in anhydrous ethanol at 65°C for 10 h, then centrifuged at 4500 r / min for 10 min, and then dried at 55°C for 20 h.

[0029] Step (4) The dried product is placed in a muffle furnace and heated to 750°C at a heating rate of 2°C / min for 2.5 hours to obtain strontium-magnesium-doped bioactive glass.

[0030] The surfactant in step (1) is a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer.

[0031] After the reaction in the high-pressure reactor in step (2) is completed, it is cooled to room temperature at a rate of 3°C.

[0032] Step (2) Drying involves heat-treating the product in an oven at 95-105℃ for 2 hours, followed by drying the product at 55℃.

[0033] The chemical composition of the strontium-magnesium-doped bioactive glass is 60% SiO2, 25% CaO, 6% SrO, 5% MgO, and 4% P2O5 (molar percentage).

[0034] An application of strontium-magnesium-doped bioactive glass involves preparing a hydration gel by combining strontium-magnesium-doped bioactive glass with mineral trioxide aggregates (MTA) at a mass ratio of 1:4, and applying it to the repair of human bone and dental pulp tissues.

[0035] Example 2.

[0036] A method for preparing strontium-magnesium-doped bioactive glass, comprising the following steps:

[0037] Step (1) Take 28.8 mL of deionized water into a beaker, adjust the pH of the solution to 1.5 with 0.5 M hydrochloric acid, and add 2.32 g of surfactant;

[0038] Step (2) Stir the solution from step (1) at 40°C until it is homogeneous and transparent. Add 7.3 mL of tetraethyl orthosilicate, 0.55 mL of triethyl phosphate and 1.53 g of calcium nitrate tetrahydrate in sequence. Stir for 28 min. Then add 2.36 g of strontium acetate and 0.46 g of magnesium oxide. Continue stirring for 25 h. Pour the mixture into a high-pressure reactor and react at 180°C and 3 MPa pressure for 3 h. Cool the mixture and remove it to dry it.

[0039] Step (3) The precipitate obtained in step (2) is refluxed in anhydrous ethanol at 70°C for 12 h, then centrifuged at 5000 r / min for 12 min, and then dried at 60°C for 25 h.

[0040] Step (4) Place the dried product in a muffle furnace and heat it to 800°C at a heating rate of 2°C / min for 3 hours to obtain strontium-magnesium-doped bioactive glass.

[0041] The surfactant in step (1) is a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer.

[0042] After the reaction in the high-pressure reactor in step (2) is completed, it is cooled to room temperature at a rate of 4°C.

[0043] Step (2) Drying involves heat-treating the product in an oven at 100°C for 25 hours, followed by drying the product at 60°C.

[0044] The chemical composition of the strontium-magnesium-doped bioactive glass is 60% SiO2, 25% CaO, 6% SrO, 5% MgO, and 4% P2O5 (molar percentage).

[0045] An application of strontium-magnesium-doped bioactive glass involves preparing a hydration gel by combining strontium-magnesium-doped bioactive glass with mineral trioxide aggregates (MTA) at a mass ratio of 1:4, and applying it to the repair of human bone and dental pulp tissues.

[0046] Example 3.

[0047] A method for preparing strontium-magnesium-doped bioactive glass, comprising the following steps:

[0048] Step (1) Take 28.8 mL of deionized water into a beaker, adjust the pH of the solution to 1.5 with 0.5 M hydrochloric acid, and add 2.32 g of surfactant;

[0049] Step (2) Stir the solution from step (1) at 42°C until it is homogeneous and transparent. Add 7.3 mL of tetraethyl orthosilicate, 0.55 mL of triethyl phosphate and 1.53 g of calcium nitrate tetrahydrate in sequence. Stir for 30 min. Then add 2.36 g of strontium acetate and 0.46 g of magnesium oxide. Continue stirring for 30 h. Pour the mixture into a high-pressure reactor and react at 200°C and 5 MPa pressure for 3.5 h. Cool the mixture and remove it to dry it.

[0050] Step (3) The precipitate obtained in step (2) is refluxed in anhydrous ethanol at 75°C for 10 h, then centrifuged at 5500 r / min for 15 min, and then dried at 65°C for 20 h.

[0051] Step (4) The dried product is placed in a muffle furnace and heated to 850°C at a heating rate of 2°C / min for 3.5 hours to obtain strontium-magnesium-doped bioactive glass.

[0052] The surfactant in step (1) is a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer.

[0053] After the reaction in the high-pressure reactor in step (2) is completed, it is cooled to room temperature at a rate of 5°C.

[0054] Step (2) Drying involves heat-treating the product in an oven at 105°C for 30 hours, followed by drying the product at 65°C.

[0055] The chemical composition of the strontium-magnesium-doped bioactive glass is 60% SiO2, 25% CaO, 6% SrO, 5% MgO, and 4% P2O5 (molar percentage).

[0056] An application of strontium-magnesium-doped bioactive glass involves preparing a hydration gel by combining strontium-magnesium-doped bioactive glass with mineral trioxide aggregates (MTA) at a mass ratio of 1:4, and applying it to the repair of human bone and dental pulp tissues.

[0057] Comparative Example 1

[0058] A method for preparing strontium-magnesium-doped bioactive glass, comprising the following steps:

[0059] Step (1) Take 28.8 mL of deionized water into a beaker, adjust the pH of the solution to 1.5 with 0.5 M hydrochloric acid, and add 2.32 g of surfactant;

[0060] Step (2) Stir the solution from step (1) at 40°C until it is homogeneous and transparent. Add 7.3 mL of tetraethyl orthosilicate, 0.55 mL of triethyl phosphate and 1.53 g of calcium nitrate tetrahydrate in sequence. Stir for 28 min. Then add 2.36 g of strontium acetate and 0.46 g of magnesium oxide. Continue stirring for 25 h. Pour the mixture into a high-pressure reactor and react at 180°C and 3 MPa pressure for 3 h. Cool the mixture and remove it to dry it.

[0061] Step (3) The precipitate obtained in step (2) is refluxed in anhydrous ethanol at 70°C for 12 h, then centrifuged at 5000 r / min for 12 min, and then dried at 60°C for 25 h.

[0062] Step (4) Place the dried product in a muffle furnace and heat it to 800°C at a heating rate of 2°C / min for 3 hours to obtain strontium-magnesium-doped bioactive glass.

[0063] The surfactant mentioned in step (1) is any commercially available nonionic surfactant. In this comparative example, polyoxyethylene sorbitan monostearate Tween 60 was used.

[0064] After the reaction in the high-pressure reactor in step (2) is completed, it is cooled to room temperature at a rate of 4°C.

[0065] Step (2) Drying involves heat-treating the product in an oven at 100°C for 25 hours, followed by drying the product at 60°C.

[0066] The chemical composition of the strontium-magnesium-doped bioactive glass is 60% SiO2, 25% CaO, 6% SrO, 5% MgO, and 4% P2O5 (molar percentage).

[0067] An application of strontium-magnesium-doped bioactive glass involves preparing a hydration gel by combining strontium-magnesium-doped bioactive glass with mineral trioxide aggregates (MTA) at a mass ratio of 1:4, and applying it to the repair of human bone and dental pulp tissues.

[0068] Comparative Example 2

[0069] A method for preparing strontium-magnesium-doped bioactive glass, comprising the following steps:

[0070] Step (1) Take 28.8 mL of deionized water into a beaker, adjust the pH of the solution to 1.5 with 0.5 M hydrochloric acid, and add 2.32 g of surfactant;

[0071] Step (2) Stir the solution from step (1) at 40°C until it is homogeneous and transparent. Add 7.3 mL of tetraethyl orthosilicate, 0.55 mL of triethyl phosphate and 1.53 g of calcium nitrate tetrahydrate in sequence. Stir for 28 min. Then add 2.36 g of strontium acetate and continue stirring for 25 h. Pour the mixture into a high-pressure reactor and react at 180°C and 3 MPa pressure for 3 h. After cooling, remove the reactants and dry them.

[0072] Step (3) The precipitate obtained in step (2) is refluxed in anhydrous ethanol at 70°C for 12 h, then centrifuged at 5000 r / min for 12 min, and then dried at 60°C for 25 h.

[0073] Step (4) Place the dried product in a muffle furnace and heat it to 800°C at a heating rate of 2°C / min for 3 hours to obtain strontium-magnesium-doped bioactive glass.

[0074] The surfactant in step (1) is a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer.

[0075] After the reaction in the high-pressure reactor in step (2) is completed, it is cooled to room temperature at a rate of 4°C.

[0076] Step (2) Drying involves heat-treating the product in an oven at 100°C for 25 hours, followed by drying the product at 60°C.

[0077] Experimental Section

[0078] 1. Scanning electron micrograph

[0079] Figure 1The images show the electron microscopy morphology of the bioactive glass prepared in Comparative Example 1 and Example 2 of the present invention. The bioactive glass powder (A) prepared in Comparative Example 1 is an irregular agglomerate, while the bioactive glass (B) of the present invention has a more regular shape and consists of spherical particles with good dispersibility.

[0080] 2. In vitro hydroxyapatite formation experiment

[0081] The strontium-containing bioactive glass particles (a) prepared in Comparative Example 2 of this invention and the strontium-doped magnesium bioactive glass particles (b) prepared in Example 2 of this invention were immersed in simulated body fluid, and the quantity and formation rate of hydroxyapatite on the surface of these two materials were observed. Figure 2 Scanning electron microscope (SEM) images of the bioactive glass particles containing only strontium (a) prepared in Comparative Example 2 of the present invention and the bioactive glass particles doped with strontium and magnesium (b) prepared in Example 2 of the present invention after mineralization for 1 day (a1, b1), 5 days (a2, b2), and 10 days (a3, b3).

[0082] from Figure 2 As can be seen, most of the hydroxyapatite is deposited within the prepared bioactive glass particles. A careful comparison of the scanning electron microscope images (SEM) of bioactive glass particles containing only strontium (a) and those doped with strontium and magnesium (b) reveals that the rate of hydroxyapatite formation on the surface of the two types of bioactive glasses differs. The bioactive glass particles containing only strontium form significantly less hydroxyapatite than those doped with strontium and magnesium. This is because the introduction of magnesium results in a faster and stronger hydroxyapatite formation ability, leading to a faster ion release rate. In simulated body fluids, it can release ions such as calcium, phosphorus, and silicon, forming more hydroxyapatite.

[0083] 3. Cell compatibility test

[0084] 3.1 Cell Culture

[0085] Human dental pulp cells were seeded in T75 culture flasks and cultured in high-glucose medium containing 10% fetal bovine serum at 37°C and 5% CO2 until the desired cell concentration was reached. Cells were then isolated from the culture flasks using a 0.25% trypsin / 0.02% EDTA-2Na solution and resuspended in high-glucose medium to the desired cell concentration for subsequent experiments.

[0086] 3.2 Cytotoxicity test

[0087] Cytotoxicity assays were performed using the CCK-8 method. Human dental pulp cells were seeded at a density of 2000 cells / well in 96-well plates. 100 μl of high-glucose medium was added to each well. After incubation in a carbon 2 incubator for 24 h, the medium was carefully removed. 100 μl of 0.5 g of strontium-magnesium-doped bioactive glass particles (Sr-Mg BGs) prepared in Example 2 of this invention and 2.0 g of trioxygen polymer aggregate (Sr-Mg-MTA BGs) were added to each well to prepare a hydration gel extraction solution. The strontium-magnesium-doped bioactive glass particles (Sr-Mg BGs) prepared in Example 2 of this invention (extraction solution preparation method: the extraction ratio of sample mass to high-glucose medium was 0.1 g / ml, and extraction was carried out at 37±1℃ for 24 h. The supernatant was then collected for use). The cells were cultured for another 12 h. 20 μl of LCK-8 solution was added to each well, and the cells were incubated at 37℃ for 1 h. The absorbance of the supernatant at 450 nm was detected using a microplate reader. Note that the extract of strontium-doped bioactive glass particles (Sr BGs) prepared in Comparative Example 2 of this invention is used as a control.

[0088] 3.3 Results of cell compatibility experiments

[0089] Figure 3 The proliferation activity of human dental pulp cells after culturing with Sr-Mg BGs and Sr-Mg-MTA BGs for 1, 3, 5, and 7 days was measured. Cells in all three groups gradually proliferated over time. Compared to the control, at 1 day of culture, Sr-Mg-MTA BGs and Sr-Mg BGs showed similar proliferation activity to the control group; at 5 days, both Sr-Mg-MTA BGs and Sr-Mg BGs significantly promoted human dental pulp cell proliferation; after 7 days of culture, the cell proliferation activity of both samples was higher than that of the control group, but the proliferation effect of Sr-Mg BGs was not as significant as that of Sr-Mg-MTA BGs. These results indicate that Sr-Mg-MTA BGs has superior cell compatibility and can be used in combination with MTA as an active material for the repair of human bone, dental pulp, and other tissues.

Claims

1. A method for preparing strontium-magnesium-doped bioactive glass, characterized in that: It includes the following steps: Step (1) Take 28.8 mL of deionized water into a beaker, adjust the pH of the solution to 1.5 with 0.5 M hydrochloric acid, and add 2.32 g of surfactant; Step (2) Stir the solution from step (1) at 38-42℃ until it is homogeneous and transparent. Add 7.3 mL of tetraethyl orthosilicate, 0.55 mL of triethyl phosphate and 1.53 g of calcium nitrate tetrahydrate in sequence. Stir for 25-30 min. Then add 2.36 g of strontium acetate and 0.46 g of magnesium oxide. Continue stirring for 20-30 h. Pour the mixture into a high-pressure reactor and react at 180-200℃ and 1-5 MPa pressure for 2.5-3.5 h. Cool the mixture and remove it to dry the reaction product. Step (3) Reflux the precipitate obtained in step (2) in anhydrous ethanol at 65-75℃ for 10-15h, then centrifuge at 4500-5500r / min for 10-15min, and then continue to dry the precipitate at 55-65℃ for 20-30h. Step (4) The dried product is placed in a muffle furnace and heated to 750-850℃ at a heating rate of 2℃ / min, and heat-treated for 2.5-3.5h to obtain strontium-magnesium-doped bioactive glass. The surfactant in step (1) is a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer.

2. The method for preparing strontium-doped magnesium bioactive glass according to claim 1, characterized in that: After the reaction in the high-pressure reactor in step (2) is completed, it is cooled to room temperature at a rate of 3-5℃.

3. The method for preparing strontium-doped magnesium bioactive glass according to claim 1, characterized in that: Step (2) Drying involves heat-treating the product in an oven at 95-105℃ for 20-30 hours, followed by drying the product at 55-65℃.

4. The method for preparing strontium-doped magnesium bioactive glass according to claim 1, characterized in that: The chemical composition of the strontium-magnesium-doped bioactive glass, in molar percentage, is 60% SiO2, 25% CaO, 6% SrO, 5% MgO, and 4% P2O5.

5. The use of a strontium-doped magnesium bioactive glass, characterized in that: The strontium-magnesium-doped bioactive glass is used for the repair of human bone and dental pulp tissues, wherein the strontium-magnesium-doped bioactive glass is prepared by the preparation method described in any one of claims 1-4.

6. The use of a strontium-doped magnesium bioactive glass according to claim 5, characterized in that: A gel was formed by hydrating strontium-magnesium-doped bioactive glass with mineral trioxide aggregates at a mass ratio of 1:4, and then applied to the repair of human bone and dental pulp tissues.

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