Cerium-doped mesoporous bioactive glass and methods of making the same

Abstract

This invention relates to the field of biomedical materials technology, and discloses a cerium-doped mesoporous bioactive glass and its preparation method. The cerium-doped mesoporous bioactive glass comprises a SiO₂-CaO-P₂O₅ glass network and cerium element doped in the glass network; the cerium-doped mesoporous bioactive glass has an amorphous mesoporous structure. This cerium-doped mesoporous bioactive glass is prepared by employing a sol-gel method combined with a water-in-oil self-assembly strategy. Using hexadecylpyridine bromide as a template agent, urea as a slow-release alkali source, and triethanolamine as a reaction regulator, a stable emulsion is constructed in an aqueous system, followed by the sequential introduction of silicon, phosphorus, calcium, and cerium sources. This successfully achieves in-situ uniform doping of cerium element in the mesoporous bioactive glass network framework. Furthermore, this method requires no subsequent modification steps, and a multifunctional material with an amorphous mesoporous structure, Ce³⁺ / Ce⁴⁺ mixed valence state, and controllable CeO₂ nanocrystal distribution can be obtained in one step.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and in particular to a cerium-doped mesoporous bioactive glass and its preparation method. Background Technology

[0002] Bioactive glasses, especially mesoporous bioactive glasses, have attracted widespread attention in biomedical fields such as bone tissue engineering, tissue repair, and drug delivery due to their excellent bioactivity, high specific surface area, and tunable pore structure. Mesoporous bioactive glasses can rapidly induce the formation of a hydroxyapatite layer on the material surface in a physiological environment, thereby promoting tissue regeneration and interfacial integration between the implant and the host bone. At the same time, their well-developed mesoporous structure is conducive to the sustained release of functional ions and the effective loading of drugs, further expanding the therapeutic potential of the material.

[0003] In recent years, introducing inorganic ions with specific therapeutic functions into the bioactive glass network framework has become an important material design strategy for endowing materials with multifunctional biological properties. Existing research has successfully introduced metal ions such as zinc, copper, and silver into bioactive glass systems, which has improved the antibacterial properties, angiogenesis ability, or osteogenic activity of the materials to a certain extent.

[0004] Among numerous candidate dopant elements, cerium has attracted increasing attention due to its unique redox properties and enzyme-like catalytic activity. Cerium ions can react with Ce³⁺ and Ce under physiological conditions. 4 ⁺ The reversible conversion between the two valence states is accompanied by the effective scavenging of reactive oxygen species and the regulation of oxidative stress levels. Furthermore, cerium has been shown to possess various beneficial biological functions, including antibacterial, anti-inflammatory, and osteogenic differentiation promotion. Preliminary studies indicate that cerium-doped mesoporous bioactive glasses can, to some extent, mimic the functions of natural antioxidant enzymes (such as superoxide dismutase and catalase), thereby mitigating oxidative damage and improving cell compatibility.

[0005] However, existing research on cerium-doped mesoporous bioactive glasses still suffers from the following key technical deficiencies: 1. Limited doping methods and insufficient research on in-situ synthesis. Existing technologies for introducing cerium mostly employ post-modification methods or low-content doping. There are limited reports on methods for directly introducing cerium in situ into the glass network framework during the synthesis of mesoporous bioactive glasses. Post-modification methods struggle to achieve uniform distribution and stable bonding of cerium in the matrix, while low-content doping fails to fully utilize the multifunctional biological effects of cerium.

[0006] 2. The relationship between cerium content and structural evolution is unclear. The effects of changes in cerium content on the evolution of the mesoporous structure of mesoporous bioactive glass, the formation conditions and distribution of CeO2 nanocrystals, and the Ce³⁺ / Ce ratio.4 The changes in the ⁺ mixed valence ratio, and their synergistic effects on ion release behavior and bioactivity, still lack systematic research and elucidation.

[0007] 3. Insufficient synergistic regulation of multi-functional performance. Existing doping schemes often focus on improving a single biological property (such as focusing only on antibacterial properties or only on antioxidant properties), failing to achieve synergistic regulation and overall optimization of multiple properties such as antioxidant activity, antibacterial properties, in vitro mineralization ability, and biocompatibility.

[0008] 4. Lack of integrated structural and functional design How to simultaneously achieve enhanced antioxidant properties, broad-spectrum antibacterial properties, and good biosafety by introducing cerium while maintaining the original amorphous mesoporous structure and excellent in vitro mineralization activity of mesoporous bioactive glass remains a technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0009] In view of the problems of existing mesoporous bioactive glass, such as limited functionality, insufficient antioxidant capacity, and weak antibacterial properties, this invention is proposed.

[0010] Therefore, the purpose of this invention is to provide a cerium-doped mesoporous bioactive glass. The purpose is to achieve in-situ uniform doping of cerium in the mesoporous bioactive glass network framework by using a sol-gel method combined with a water-in-oil self-assembly strategy, using hexadecylpyridine bromide as a template agent, urea as a slow-release alkali source, and triethanolamine as a reaction regulator, and then sequentially introducing silicon source, phosphorus source, calcium source and cerium source after constructing a stable emulsion in an aqueous system.

[0011] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a cerium-doped mesoporous bioactive glass, wherein the cerium-doped mesoporous bioactive glass comprises a SiO2-CaO-P2O5 glass network and cerium element doped in the glass network; the cerium-doped mesoporous bioactive glass has an amorphous mesoporous structure.

[0012] As a preferred embodiment of the cerium-doped mesoporous bioactive glass of the present invention, the cerium-doped mesoporous bioactive glass has a pore size distribution of 5nm to 20nm, a specific surface area of ​​300m² / g to 470m² / g, a pore volume of 1.2cm³ / g to 1.9cm³ / g, and an average pore size of 14nm to 18nm.

[0013] As a preferred embodiment of the cerium-doped mesoporous bioactive glass of the present invention, wherein: the cerium is in the form of Ce³⁺ and Ce 4⁺ Mixed valence states exist in the cerium-doped mesoporous bioactive glass, and as the cerium content increases, CeO2 nanocrystals dispersed in the glass matrix are formed in the cerium-doped mesoporous bioactive glass.

[0014] As a preferred embodiment of the cerium-doped mesoporous bioactive glass of the present invention, the cerium-doped mesoporous bioactive glass is formed by the aggregation of nanoscale particles, the nanoscale particles being spherical or flower-shaped with rough surfaces and forming an interconnected porous structure.

[0015] In a preferred embodiment of the present invention, a method for preparing a cerium-doped mesoporous bioactive glass includes the following steps: S1. Preparation of the template system: The template agent, the slow-release alkali source and the reaction regulator are dissolved in deionized water, ultrasonically dispersed and stirred evenly to obtain an aqueous system; S2. Construction of the emulsion system: Add oil phase and co-solvent to the aqueous system obtained in step S1, and stir to form a stable emulsion; S3. Silicon source introduction and polycondensation reaction: Add silicon source dropwise to the emulsion obtained in step S2, stir at room temperature and then heat and reflux to react. S4. Introduction of phosphorus source, calcium source and cerium source: Phosphorus source, calcium source and cerium source are added to the system obtained in step S3 in sequence, and the reaction is continued to be stirred to obtain a cerium-containing glass precursor suspension. S5. Separation and purification of precursors: The cerium-containing glass precursor suspension obtained in step S4 is aged, centrifuged and washed to obtain precursor precipitate. S6. Calcination to form pores: The precursor precipitate obtained in step S5 is calcined to remove the template agent, thereby obtaining the cerium-doped mesoporous bioactive glass.

[0016] In a preferred embodiment of the present invention, in step S1, the template agent is hexadecylpyridine bromide, the slow-release alkali source is urea, and the reaction regulator is triethanolamine; the amount of urea added is 0.6g, the amount of hexadecylpyridine bromide added is 1.0g, the amount of triethanolamine added is 0.3mL, and the volume of deionized water is 30mL.

[0017] In a preferred embodiment of the present invention, in step S2, the oil phase is cyclohexane, the co-solvent is isopropanol, the volume of cyclohexane added is 30 mL, the amount of isopropanol added is 0.92 g, and the stirring time is 1 h.

[0018] In a preferred embodiment of the present invention, in step S3, the silicon source is tetraethyl orthosilicate, the amount of tetraethyl orthosilicate added is 2.68 mL, the dropping rate is 2 mL / min, and after stirring at 25°C for 30 min, the reaction is refluxed at 70°C for 7.5 h.

[0019] In a preferred embodiment of the present invention, in step S4, the phosphorus source is triethyl phosphate, and the amount added is 0.30 mL; the calcium source is calcium nitrate tetrahydrate, and the amount added is 1.4 g; the cerium source is cerium nitrate hexahydrate, and the amount added is 0.6 g, 1.2 g, or 1.8 g; the phosphorus source, calcium source, and cerium source are added sequentially to the system obtained in step S3, and the reaction is continued after each component is added.

[0020] As a preferred embodiment of the present invention, in step S5, the aging conditions are aging at 37°C for 48 hours, the centrifugation conditions are centrifugation at 8000 rpm for 10 minutes, and the washing method is washing twice with anhydrous ethanol and then washing once with deionized water; in step S6, the calcination conditions are heating to 600°C at a heating rate of 2-5°C / min and holding at that temperature for 5 hours.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: 1. This invention employs a sol-gel method combined with a water-in-oil self-assembly strategy. Using hexadecylpyridine bromide as a template agent, urea as a slow-release alkali source, and triethanolamine as a reaction regulator, a stable emulsion is constructed in an aqueous system. Following the sequential introduction of silicon, phosphorus, calcium, and cerium sources, in-situ uniform doping of cerium into a mesoporous bioactive glass network framework is successfully achieved. Furthermore, this method requires no subsequent modification steps, obtaining a single step that yields an amorphous mesoporous structure with a Ce³⁺ / Ce²⁺ ratio. 4 Multifunctional material with mixed valence states and controllable CeO2 nanocrystal distribution.

[0022] 2. This invention introduces cerium into a glass network, enabling the material to simultaneously contain Ce³⁺ and Ce with reversible redox activity. 4 ⁺ Furthermore, with the increase of cerium content, CeO2 nanocrystals can be formed uniformly dispersed in the glass matrix. The unique structure enables the material to have significantly enhanced ABTS free radical scavenging ability and superoxide dismutase-like activity. Moreover, this activity increases with the increase of cerium doping amount, which can effectively remove excess reactive oxygen free radicals in the pathological microenvironment.

[0023] 3. The material of this invention possesses a mesoporous pore size distribution of 5–20 nm, a high specific surface area of ​​300–470 m² / g, and a pore volume of 1.2–1.9 cm³ / g, exhibiting a well-developed mesoporous structure. This material can effectively induce hydroxyapatite formation in simulated body fluids, maintaining good in vitro mineralization activity. Simultaneously, the incorporation of cerium imparts a significant inhibitory effect on *Escherichia coli* and *Staphylococcus aureus*, achieving a synergistic enhancement of mineralization activity and antibacterial properties.

[0024] 4. Cell compatibility tests have confirmed that the cell viability of the material of this invention remains above 90% under different concentrations and culture times, with no obvious cytotoxicity; the hemolysis rate is less than 5%, which meets the safety requirements for blood compatibility of biomedical materials. It can be used as a safe candidate for biomedical materials related to bone tissue repair, bone regeneration and bone tissue engineering. Moreover, the preparation method has clear process steps and well-defined operating parameters. The amount of each component added, reaction temperature, reaction time and calcination conditions have been optimized and determined. No special equipment is required, which is convenient for industrial scale-up and mass production. Attached Figure Description

[0025] Figure 1 The images show the morphology and elemental distribution of MBG and Ce-MBG with different cerium doping levels in Example 1 of the present invention (transmission electron microscopy (TEM) image (a), scanning electron microscopy (SEM) image (b), and elemental distribution (EDS) image (c)). Figure 2 The images show the structure and chemical characterization of MBG and Ce-MBG with different cerium doping levels in the embodiments of the present invention (X-ray diffraction (XRD) pattern (a), Fourier transform infrared (FTIR) pattern (b), X-ray photoelectron spectroscopy (XPS) full spectrum (c) and Ce3d high-resolution spectrum (d)). Figure 3 Nitrogen adsorption-desorption isotherms and pore size distribution diagrams of MBG and Ce-MBG with different cerium doping amounts in the embodiments of the present invention. Figure 4 The diagram shows the ion release behavior of MBG and Ce-MBG with different cerium doping levels in simulated physiological solutions in an embodiment of the cerium-doped mesoporous bioactive glass of the present invention. Figure 5 The following figures illustrate the antioxidant and in vitro mineralization properties of MBG and Ce-MBG with different cerium doping levels in the examples of the cerium-doped mesoporous bioactive glass of the present invention (apparent results of the ABTS free radical scavenging experiment for each group of samples (a), ABTS free radical scavenging diagram (b), SOD sample activity diagram (c), and XRD diagram after mineralization (d)). Figure 6 The images show in vitro biocompatibility test results of MBG and Ce-MBG with different cerium doping levels in the embodiments of the present invention (including CCK-8 cell viability graph (a), hemolysis image (b) and hemolysis rate analysis graph (c)). Figure 7The figures show the colony-forming ability (a), antibacterial rate (b), and colony-forming ability (c), and antibacterial rate (d) of MBG and Ce-MBG with different cerium doping amounts against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in the examples of cerium-doped mesoporous bioactive glass of the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] I. Preparation of Cerium-Doped Mesoporous Bioactive Glass Example 1: Synthesis of cerium-doped mesoporous bioactive glasses (Ce-MBG) with different cerium contents This embodiment uses a sol-gel method combined with a water-in-oil self-assembly method to prepare cerium-doped mesoporous bioactive glass. The specific steps are as follows: S1, Preparation of the template system Weigh 0.6g of urea as a slow-release alkali source, 1.0g of hexadecylpyridine bromide as a template agent, and 0.3mL of triethanolamine as a reaction regulator. Add them to 30mL of deionized water, ultrasonically disperse until the solution is clear, and continue stirring to make the system homogeneous, thus obtaining an aqueous phase system.

[0028] S2, Construction of the emulsion system Add 30 mL of cyclohexane as the oil phase and 0.92 g of isopropanol as the co-solvent to the aqueous phase system obtained in step S1, and stir vigorously for 1 hour to form a stable water-in-oil emulsion.

[0029] S3, silicon source introduction and polycondensation reaction 2.68 mL of tetraethyl orthosilicate was added dropwise to the emulsion obtained in step S2 at a rate of 2 mL / min as a silicon source. After stirring at 25 °C for 30 min, the mixture was refluxed at 70 °C for 7.5 h to allow the silicon source to fully hydrolyze and condense.

[0030] Introduction of S4, phosphorus source, calcium source and cerium source To the system obtained in step S3, 0.30 mL of triethyl phosphate was added sequentially as a phosphorus source, and 1.4 g of calcium nitrate tetrahydrate was added as a calcium source. After each addition, the mixture was stirred for 30 min. Finally, cerium nitrate hexahydrate was added as a cerium source, with addition amounts of 0 g, 0.6 g, 1.2 g, and 1.8 g, respectively. The mixture was stirred for 12 min to obtain cerium-free blank control samples (MBG) and cerium-doped glass precursor suspensions with different amounts of cerium. Based on the amount of cerium source added, the resulting samples were named MBG, 5Ce-MBG, 10Ce-MBG, and 15Ce-MBG, respectively.

[0031] S5. Precursor separation and purification The cerium-containing glass precursor suspension obtained in step S4 was aged at 37°C for 48 hours, then centrifuged at 8000 rpm for 10 minutes, the supernatant was discarded, and the resulting precipitate was washed twice with anhydrous ethanol and once with deionized water to obtain the precursor precipitate.

[0032] S6, Calcination to form pores The precursor precipitate obtained in step S5 is placed in a muffle furnace and heated to 600°C at a heating rate of 2-5°C / min. The temperature is maintained for 5 hours to fully remove the template agent. After natural cooling to room temperature, cerium-doped mesoporous bioactive glass powder is obtained.

[0033] Figure 1 The characterization results of Ce-MBG prepared in this embodiment are shown. For example... Figure 1 aTEM images show that all samples exhibit typical mesoporous bioactive glass nanostructures with loosely aggregated particles. Undoped MBG samples show relatively uniform spherical or flower-like nanoparticles with a clear porous framework. The introduction of cerium did not significantly disrupt the overall morphology of the samples, indicating that the introduction of cerium did not destroy the mesoporous structure. With increasing cerium content, the degree of particle aggregation gradually increased, with 5Ce-MBG and 10Ce-MBG showing a more pronounced aggregation trend than MBG, while 15Ce-MBG exhibited a more dense aggregate. Figure 1 bSEM images showed that all samples were composed of nanoscale particles with rough surfaces, forming interconnected porous structures, without obvious structural collapse or severe phase separation. EDS elemental distribution analysis was performed using 10Ce-MBG as a representative sample. EDS... Figure 1 As shown in Figure c, Si, P, Ca, and Ce elements are uniformly distributed in the sample, confirming that cerium has been successfully introduced into the mesoporous bioactive glass system.

[0034] II. Structural and Morphological Characterization Example 2: Morphology and Elemental Distribution Characterization X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were performed on the MBG, 5Ce-MBG, 10Ce-MBG, and 15Ce-MBG samples prepared in Example 1. Figure 2 aXRD results showed that all samples exhibited broad, diffuse diffraction peaks at approximately 23°, indicating that the material as a whole maintained an amorphous silicate glass network structure. With increasing cerium doping concentration, weak diffraction peaks gradually appeared at approximately 28.5° and 33.1°, which can be attributed to the cubic fluorite CeO2 structure. This suggests that some cerium precipitated from the glass network during calcination and formed CeO2 nanocrystals, thus giving the material a structural characteristic of coexisting amorphous glass matrix and dispersed nanocrystals. Figure 2bFTIR results showed that all samples exhibited typical Si-O-Si absorption peaks, with the peak at approximately 1080 cm⁻¹ representing the antisymmetric stretching vibration of Si-O-Si, and the peaks at approximately 800 cm⁻¹ and 460 cm⁻¹ corresponding to symmetric stretching and bending vibrations, respectively. The introduction of cerium caused a slight shift in the characteristic Si-O-Si absorption band towards lower wavenumbers, indicating that cerium doping had a modulating effect on the local glass network structure. Figure 2 cXPS full spectrum results showed that the cerium-doped sample contained Si, O, Ca, P and Ce elements. Figure 2 The high-resolution Ce3d spectrum further indicates that Ce³⁺ and Ce are present simultaneously in the sample. 4 The presence of two valence states indicates that cerium exists in the material in a mixed valence state.

[0035] Example 3: Characterization of phase structure, chemical state and pore structure Nitrogen adsorption-desorption tests were performed on the MBG, 5Ce-MBG, 10Ce-MBG, and 15Ce-MBG samples prepared in Example 1. Their specific surface area, pore volume, and pore size distribution were analyzed using the BET and BJH methods. The results are as follows: Figure 3 As shown in Table 1, all samples exhibited typical Type IV adsorption-desorption isotherms with significant hysteresis loops, indicating that the materials all formed well-developed mesoporous structures. Pore size distribution results showed that the mesopores in each sample were mainly distributed in the range of 5–20 nm. These results indicate that cerium doping has a regulatory effect on the mesoporous structure parameters of the materials, but does not disrupt the overall mesoporous framework.

[0036] The pore structure parameters of each group of samples are detailed in Table 1.

[0037] Table 1: Pore structure parameters of each group of samples Table 1 shows that the BET specific surface area of ​​Ce-MBG samples with different cerium doping levels ranged from 301.35 to 460.90 m² / g, the pore volume ranged from 1.28 to 1.89 cm³ / g, and the average pore diameter ranged from 14.97 to 18.00 nm. Cerium doping has a regulatory effect on the mesoporous structure parameters of the material, but the overall mesoporous framework structure is maintained.

[0038] III. Performance Testing Example 4: Ion release behavior test.

[0039] The MBG, 5Ce-MBG, 10Ce-MBG, and 15Ce-MBG samples prepared in Example 1 were immersed in simulated physiological solutions, and the release behavior of Si, Ca, P, and Ce ions was determined by ICP-OES. Figure 4 The ion release behavior of each group in simulated physiological solutions is shown. All samples exhibited obvious time-dependent ion release characteristics. Figure 4The Si ion release curve shows that the Si ion concentration increases rapidly in the early stage of immersion and tends to plateau in the later stage. Figure 4 The bCa²⁺ release curve shows that the Ca²⁺ ion concentration first increases and then decreases. Figure 4 The cPO4³⁻ release curve shows that the PO4³⁻ ion concentration also exhibits a trend of first increasing and then decreasing; Figure 4 The dCe ion release curves show that Ce ions are released slowly and continuously, without any obvious burst release phenomenon, and their release concentration increases with increasing cerium doping concentration. This indicates that doping can regulate the glass network connectivity and ion release kinetics of the material, thus providing a basis for subsequent mineralization and bioactivity expression.

[0040] Example 5: Antioxidant and in vitro mineralization performance tests The samples prepared in Example 1 were subjected to ABTS free radical scavenging experiments, WST-8 SOD-like activity tests, and mineralization capacity evaluations after simulated body fluid immersion. The results are as follows: Figure 5 As shown. Figure 5 Figure a shows the apparent results of the ABTS free radical scavenging experiment for each group of samples. In the ABTS experiment, the blue-green color of the ABTS solution after sample treatment gradually faded, and the fading degree became more obvious with the increase of cerium content, indicating that the free radical scavenging ability was enhanced. Figure 5 The quantitative results further showed that the ABTS radical scavenging ability of Ce-MBG samples was significantly higher than that of undoped MBG, with the 15Ce-MBG group showing the highest level. Figure 5 The cSOD-like activity test results showed that the SOD-like activity of all cerium-doped samples was higher than that of MBG, and gradually increased with increasing cerium content. The 15Ce-MBG group showed the strongest superoxide dismutase-like activity. In the in vitro mineralization experiment, the samples were immersed in simulated body fluid at 37℃ for 7 days. Figure 5 XRD results after mineralization showed that all samples exhibited characteristic diffraction peaks of hydroxyapatite, indicating that all samples could induce hydroxyapatite formation and had good in vitro mineralization ability, and that the introduction of cerium did not inhibit the mineralization process.

[0041] Example 6: Cell compatibility and blood compatibility tests L929 fibroblasts were used to test the CCK-8 cell viability of the samples prepared in Example 1, and their blood compatibility was evaluated by hemolysis experiment. Figure 6 The aCCK-8 results showed that at concentrations of 5, 20, and 100 μg / mL, the cell viability of each group of samples remained above 90% after 1, 3, and 5 days of culture, with no significant differences between the groups, indicating that the material had no obvious cytotoxicity and good cell compatibility. Figure 6b. The hemolysis test results showed that no obvious red hemolysis phenomenon was observed in the supernatant of each group of samples after treatment; Figure 6 c. Hemolysis rate analysis showed that the hemolysis rate of all samples was less than 5%, and there was no significant difference between different groups, indicating that the material has good blood compatibility.

[0042] Example 7: Antibacterial Performance Test The antibacterial properties of MBG, 5Ce-MBG, 10Ce-MBG and 15Ce-MBG samples prepared in Example 1 were evaluated using the drop plate method. The tested bacterial species were Escherichia coli and Staphylococcus aureus. Figure 7 a and 7b are graphs showing E. coli colony formation and antibacterial rate, respectively. For E. coli, the MBG group showed only a weak inhibitory effect, while the 5Ce-MBG, 10Ce-MBG, and 15Ce-MBG groups showed significantly improved antibacterial rates and significantly reduced colony counts. Figure 7 Figures c and 7d show the colony formation of Staphylococcus aureus and the statistical graph of its antibacterial rate, respectively. For Staphylococcus aureus, the MBG group showed a lower antibacterial rate, while the cerium-doped groups all exhibited stronger antibacterial activity. Overall, cerium doping significantly improved the antibacterial ability of mesoporous bioactive glass against both Gram-negative and Gram-positive bacteria.

[0043] IV. Comprehensive Evaluation Example 8: Performance mechanism analysis and comprehensive evaluation of cerium-doped mesoporous bioactive glass.

[0044] Based on the preparation process and performance test results of Examples 1 to 7 above, this example analyzes the structural characteristics, mechanism of action, and comprehensive performance of the cerium-doped mesoporous bioactive glass prepared by the present invention.

[0045] This invention successfully prepared cerium-doped mesoporous bioactive glass with an amorphous mesoporous structure using a sol-gel method combined with a water-in-oil self-assembly strategy. As shown in Examples 1 to 3, the cerium-doped mesoporous bioactive glass prepared by this invention maintains its amorphous mesoporous structure. The introduction of cerium did not significantly disrupt the material's mesoporous framework; the resulting samples still possessed a large specific surface area, high pore volume, and a mesoporous distribution within the range of 5–20 nm. Simultaneously, the material is formed by the aggregation of nanoscale particles, resulting in a rough surface and an interconnected porous structure. These structural characteristics facilitate sufficient ion exchange and surface reactions between the material and the liquid environment, providing a structural basis for subsequent mineralization deposition, antioxidant effects, and antibacterial activities.

[0046] As can be seen from Example 2, cerium in the material of the present invention is in the form of Ce³⁺ and Ce. 4The presence of mixed valence states, and the formation of CeO2 nanocrystals dispersed within the glass matrix under high cerium doping conditions, demonstrates the successful introduction of cerium into the mesoporous bioactive glass system, endowing the material with reversible redox activity. This mixed valence structure is a crucial foundation for the material's enhanced antioxidant properties.

[0047] As shown in Example 4, the material of the present invention exhibits continuous and coordinated ion release behavior in simulated physiological solutions. Specifically, the release of Si and Ca ions indicates that the glass network can undergo moderate dissolution in the liquid environment, thereby enhancing the reactivity of the material surface; the dynamic change in PO4³⁻ concentration indicates its participation in the calcium-phosphorus deposition process on the material surface; Ce ions are released continuously without significant burst release, indicating that cerium is relatively stably distributed in the glass matrix and can provide a continuous effect during use. The above-mentioned ion release behavior is conducive to the formation of a mineralized microenvironment on the material surface.

[0048] As shown in Example 5, with the increase of cerium doping content, the scavenging ability of each group of samples for ABTS free radicals and the SOD-like activity both showed an enhanced trend, indicating that the introduction of cerium significantly improved the antioxidant performance of the material. Meanwhile, all groups of samples could induce hydroxyapatite formation after immersion in simulated body fluids, indicating that the material of the present invention maintains good in vitro mineralization ability while acquiring antioxidant activity.

[0049] As shown in Example 6, none of the samples exhibited significant cytotoxicity under different concentrations and culture times, and the hemolysis rate was less than 5%, indicating that the material of the present invention has good cell compatibility and blood compatibility, and can meet the basic safety requirements of biomedical materials.

[0050] As shown in Example 7, the inhibitory effect of cerium-doped material on Escherichia coli and Staphylococcus aureus was significantly enhanced, indicating that the introduction of cerium helps to improve the antibacterial properties of mesoporous bioactive glass. Combining the results of Examples 2 and 4, it can be seen that the improvement in antibacterial properties is related to the redox activity imparted to the material by cerium and the continuous release of Ce ions. Simultaneously, the material's large specific surface area and mesoporous structure also facilitate sufficient contact with bacteria, thereby further enhancing the antibacterial effect.

[0051] In summary, this invention achieves synergistic regulation of the mesoporous structure, ion release behavior, and redox activity of mesoporous bioactive glass by introducing cerium into the material. The resulting cerium-doped mesoporous bioactive glass, while maintaining its amorphous mesoporous structure and good in vitro mineralization ability, further exhibits enhanced antioxidant and antibacterial properties, as well as good cell and blood compatibility, indicating its promising application prospects in bone tissue repair, bone regeneration, and bone tissue engineering.

[0052] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A cerium-doped mesoporous bioactive glass, characterized in that, The cerium-doped mesoporous bioactive glass comprises a SiO2-CaO-P2O5 glass network and cerium element doped in the glass network; the cerium-doped mesoporous bioactive glass has an amorphous mesoporous structure.

2. The cerium-doped mesoporous bioactive glass according to claim 1, characterized in that: The cerium-doped mesoporous bioactive glass has a pore size distribution of 5 nm to 20 nm, a specific surface area of ​​300 m² / g to 470 m² / g, a pore volume of 1.2 cm³ / g to 1.9 cm³ / g, and an average pore size of 14 nm to 18 nm.

3. The cerium-doped mesoporous bioactive glass according to claim 2, characterized in that: The cerium is present in mixed valence states of Ce3+and Ce 4 ⁺mixed valence states in the cerium-doped mesoporous bioactive glass, and with increasing cerium content, CeO2nanocrystals dispersed in the glass matrix are formed in the cerium-doped mesoporous bioactive glass.

4. The cerium-doped mesoporous bioactive glass according to claim 3, characterized in that: The cerium-doped mesoporous bioactive glass is formed by the aggregation of nanoscale particles, which are spherical or flower-shaped, with rough surfaces, and form an interconnected porous structure.

5. A method for preparing cerium-doped mesoporous bioactive glass, which is applied to the cerium-doped mesoporous bioactive glass described in claim 4, characterized in that: Includes the following steps: S1. Preparation of the template system: The template agent, the slow-release alkali source and the reaction regulator are dissolved in deionized water, ultrasonically dispersed and stirred evenly to obtain an aqueous system; S2. Construction of the emulsion system: Add oil phase and co-solvent to the aqueous system obtained in step S1, and stir to form a stable emulsion; S3. Silicon source introduction and polycondensation reaction: Add silicon source dropwise to the emulsion obtained in step S2, stir at room temperature and then heat and reflux to react. S4. Introduction of phosphorus source, calcium source and cerium source: Phosphorus source, calcium source and cerium source are added to the system obtained in step S3 in sequence, and the reaction is continued to be stirred to obtain a cerium-containing glass precursor suspension. S5. Separation and purification of precursors: The cerium-containing glass precursor suspension obtained in step S4 is aged, centrifuged and washed to obtain precursor precipitate. S6. Calcination to form pores: The precursor precipitate obtained in step S5 is calcined to remove the template agent, thereby obtaining the cerium-doped mesoporous bioactive glass.

6. The method for preparing cerium-doped mesoporous bioactive glass according to claim 5, characterized in that: In step S1, the template agent is hexadecylpyridine bromide, the slow-release alkali source is urea, and the reaction regulator is triethanolamine; the amount of urea added is 0.6g, the amount of hexadecylpyridine bromide added is 1.0g, the amount of triethanolamine added is 0.3mL, and the volume of deionized water is 30mL.

7. The method for preparing cerium-doped mesoporous bioactive glass according to claim 6, characterized in that: In step S2, the oil phase is cyclohexane, the co-solvent is isopropanol, the volume of cyclohexane added is 30 mL, the amount of isopropanol added is 0.92 g, and the stirring time is 1 h.

8. The method for preparing cerium-doped mesoporous bioactive glass according to claim 7, characterized in that: In step S3, the silicon source is tetraethyl orthosilicate, the amount of tetraethyl orthosilicate added is 2.68 mL, the dropping rate is 2 mL / min, and after stirring at 25 °C for 30 min, the reaction is refluxed at 70 °C for 7.5 h.

9. The method for preparing cerium-doped mesoporous bioactive glass according to claim 8, characterized in that: In step S4, the phosphorus source is triethyl phosphate, and the amount added is 0.30 mL; the calcium source is calcium nitrate tetrahydrate, and the amount added is 1.4 g; the cerium source is cerium nitrate hexahydrate, and the amount added is 0.6 g, 1.2 g, or 1.8 g; the phosphorus source, calcium source, and cerium source are added sequentially to the system obtained in step S3, and the reaction is continued after each component is added.

10. The method for preparing cerium-doped mesoporous bioactive glass according to claim 9, characterized in that: In step S5, the aging conditions are aging at 37℃ for 48 hours, centrifugation conditions are centrifugation at 8000 rpm for 10 minutes, and washing methods are washing twice with anhydrous ethanol and then washing once with deionized water; in step S6, the calcination conditions are heating to 600℃ at a heating rate of 2-5℃ / min and holding at that temperature for 5 hours.

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