Blood vessel promoting and antibacterial double-effect composite bone cement and preparation method thereof

Abstract

The invention provides blood vessel promoting and antibacterial double-effect composite bone cement and a preparation method thereof, and belongs to the technical field of medical biological materials. The preparation method comprises the following steps: carrying out esterification reaction on methacrylic anhydride and hydroxyl of bacterial cellulose (BC) in anhydrous N, N-dimethylformamide to prepare modified cellulose (BC-MA) of which the surface contains methylacryloyl; the preparation method comprises the following steps: mixing BC-MA with an ethanol solution containing Roxadustat, and carrying out vacuum drying, so as to obtain a medicine carrying material BC-MA (at) Roxa; then spraying a high-concentration gentamicin sulfate aqueous solution on the BC-MA-coated Roxa, and carrying out freeze drying and grinding, so as to obtain a double-drug carrier BC-MA-coated Roxa-coated Genta; and mixing the powder with PMMA bone cement powder in proportion, adding a liquid-phase monomer, stirring and curing to obtain the BC-MA-coated Roxa-coated Genta / PMMA composite bone cement. The BC-MA (at) Roxa (at) Genta / PMMA composite bone cement prepared by the invention has relatively high porosity and connectivity, high drug loading capacity, stable release process and long duration time. The material realizes the functionalization of antibiosis and blood vessel promotion, and provides good biological activity and tissue integration performance for bone repair.

Description

Technical Field

[0001] This application relates to a vascular-promoting and antibacterial dual-effect composite bone cement and its preparation method, belonging to the field of medical biomaterial preparation technology. Background Technology

[0002] With the increasing aging population and the growing number of clinical cases of osteoarthritis, bone defects, and fractures, the number of artificial joint replacement and bone repair surgeries is rising year by year, placing higher demands on the comprehensive performance and biocompatibility of bone cement materials. Polymethyl methacrylate (PMMA) bone cement, due to its advantages such as minimal surgical trauma, excellent mechanical properties, good formability, and ease of use, has become the most widely used fixation and filling material in clinical orthopedic surgery.

[0003] However, with the deepening of clinical use, its inherent defects have become a key bottleneck restricting clinical efficacy: First, PMMA is a bioinert material with a lack of osteoconductive and osteoinductive activity on its surface. It only forms a "mechanical interlock" with the host bone tissue rather than a "biological bond", which easily leads to interface loosening after surgery. Second, the PMMA matrix is ​​dense and non-porous. When traditional physical mixing of antibacterial drugs is carried out, the drug release performance is poor, the drug release amount is low and the cycle is short, making it difficult to achieve long-term antibacterial effect and easily leading to problems such as postoperative infection and insufficient bone integration.

[0004] Chinese patent application CN110075351A discloses a dual-drug-release PMMA composite bone cement, which uses porous gelatin microspheres loaded with osteoporosis drugs and antibiotics. The porous structure of the microspheres achieves a phased drug release effect: rapid initial release of antibiotics for anti-infection and slow long-term release of osteoporosis drugs to improve bone density, thus addressing to some extent the problem of low drug release rates in traditional physical mixing methods. However, this technology suffers from several drawbacks. First, the interfacial bonding stability is insufficient. The gelatin microspheres and PMMA matrix are only physically mixed, making them prone to aggregation and sedimentation during stirring or curing, leading to fluctuations in the mechanical properties of the composite bone cement. Second, the carrier degradation and drug release are not well-matched. Gelatin's degradation cycle in vivo is approximately 4-8 weeks, shorter than the 3-6 months required for bone healing, leading to premature degradation and interruption of later drug release. Furthermore, the porous structure of the microspheres is susceptible to collapse due to erosion by body fluids, posing a risk of sudden drug release.

[0005] Therefore, developing a multifunctional composite bone cement that can simultaneously address issues such as weak interfacial bonding and long-term sustained drug release has become an urgent need in the field of orthopedic materials. Summary of the Invention

[0006] To address the aforementioned issues, a dual-effect composite bone cement with both angiogenic and antibacterial properties is provided, along with its preparation method. This involves modifying bacterial cellulose with methacryloyl groups and loading it with the angiogenic drug roxadustat and the antibacterial drug gentamicin sulfate using a specific method. The modified bacterial cellulose, functionalized with both drugs, is then combined with PMMA bone cement to construct a dual-effect composite bone cement possessing mechanical strength, antibacterial properties, and angiogenic activity.

[0007] According to one aspect of this application, a method for preparing a vascular-promoting and antibacterial dual-effect composite bone cement is provided, comprising the following steps: (1) Bacterial cellulose BC was modified by methacrylylation to obtain modified bacterial cellulose BC-MA with methacrylyl groups on the surface; (2) BC-MA was mixed with a solution containing Roxadustat and dried under vacuum to obtain the drug-loaded material BC-MA@Roxadustat; (3) Spray gentamicin sulfate aqueous solution onto BC-MA@Roxa, freeze-dry and grind to obtain the dual drug carrier BC-MA@Roxa@Genta; (4) The dual-drug carrier BC-MA@Roxa@Genta is mixed with polymethyl methacrylate bone cement powder and MMA mixture is added and stirred and solidified to obtain the angiogenic and antibacterial dual-effect composite bone cement.

[0008] Optionally, in step (1), bacterial cellulose is dispersed in anhydrous N,N-dimethylformamide, and methacrylic anhydride and equimolar triethylamine are added dropwise while stirring at low temperature. After heating, the reaction is carried out in the dark. After washing and vacuum drying, modified cellulose BC-MA with methacryloyl groups on the surface is obtained.

[0009] Bacterial cellulose (BC) is a natural polymer material with excellent biocompatibility and non-toxic biodegradability in vivo. Its three-dimensional nanofiber network structure is similar to the extracellular matrix (ECM), providing a good supporting environment for cell adhesion and spreading. However, bacterial cellulose has a highly polar surface, resulting in significant compatibility differences with hydrophobic polymers. This can easily lead to uneven phase distribution and weak interfacial bonding, thus affecting the overall performance of the composite system. Furthermore, although bacterial cellulose is beneficial for cell adhesion, its promoting effect on cell differentiation and angiogenesis is limited.

[0010] Therefore, this application specifically modifies the surface of bacterial cellulose by introducing reactive functional groups and drug loading sites to enhance its interfacial bonding ability with the polymer matrix and improve the drug release performance and angiogenesis induction activity of the material.

[0011] Bacterial cellulose (BC) has a surface rich in hydroxyl groups (-OH). This application introduces methacryl groups onto the BC surface through the esterification reaction of methacrylic anhydride (MA), forming modified cellulose BC-MA. This functional group can undergo a free radical copolymerization reaction with methyl methacrylate (MMA) monomers in the liquid phase of PMMA bone cement during the curing process, forming covalent bonds. This upgrades the "physical intercalation" of BC-MA and the PMMA matrix to "molecular bonding," significantly reducing interfacial stress concentration and substantially improving the interfacial bonding strength and mechanical stability of the composite material.

[0012] Meanwhile, the three-dimensional network structure of BC nanofibers remains intact after modification. When composited, it can act as a mechanical reinforcing skeleton dispersed in the PMMA matrix, effectively blocking crack propagation. When the composite bone cement is subjected to external force, BC-MA fibers can dissipate energy through fiber pull-out and crack bridging effects, avoiding brittle fracture of the matrix.

[0013] Optionally, in step (1), the ratio of bacterial cellulose to anhydrous N,N-dimethylformamide is 1.0 g:(50-100) mL; and the degree of substitution of BC-MA is 0.05-0.20.

[0014] By limiting the ratio of bacterial cellulose (BC) to anhydrous N,N-dimethylformamide (DMF) (1.0 g : 50-100 mL), BC nanofibers / microfibers are more fully dispersed, ensuring effective contact between methacrylic anhydride (MA) and the hydroxyl groups on the fiber surface, thereby improving the grafting rate, laying the structural foundation for uniform grafting of methacryloyl groups, and ensuring the uniformity of subsequent dual-drug loading and the stability of interfacial bonding.

[0015] Optionally, in step (1), the low temperature is 0-5℃, the heating reaction temperature is 35-40℃, the reaction time in the dark is 2h-4h, and the vacuum drying temperature is 40-50℃ until the material reaches constant weight.

[0016] Preferably, in step (1), 1.0 g of bacterial cellulose powder is dispersed in anhydrous N,N-dimethylformamide (50-100 mL), and methacrylic anhydride (0.3-1.0 mL) and an equimolar amount of triethylamine are added dropwise while stirring under ice bath (0-5℃) conditions; then the temperature is raised to 40℃ and stirred for 2-4 h (protected from light and anhydrous throughout). After the reaction is complete, the mixture is washed thoroughly with ethanol and deionized water until neutral, and then dried under vacuum at 40-50℃ to constant weight to obtain BC-MA.

[0017] Optionally, in step (2), an ethanol-water solution of roxadustat needs to be prepared. The BC-MA obtained in step (1) is completely immersed in the solution, left to stand in the dark, the supernatant is discarded, and then vacuum dried, ground and sieved to obtain BC-MA@Roxa. The concentration of roxadustat in an ethanol-water solution is 0.1-1.0 mg / mL. By limiting its concentration, the drug release rate can be effectively controlled, achieving a sustained vasoproliferative effect.

[0018] Preferably, in step (2), the ethanol-water solution of roxadustat has a mass concentration of 0.1-1.0 mg / mL and a volume fraction of ethanol of 20%-30% (v / v); the time for standing at room temperature (25°C) in the dark is 24 h; the temperature for vacuum drying is 40°C and the time is 4 h; and the grinding and sieving are done through a ≤150 mesh sieve.

[0019] Specifically, prepare a Roxadustat (FG-4592) solution of 0.1-1.0 mg / mL in 20-30% (v / v) ethanol / water; completely immerse BC-MA in this solution and let it stand at room temperature in the dark for 24 h. Discard the supernatant, place in a vacuum oven at 40℃ and dry at low temperature for 4 h, then grind and pass through a ≤150 mesh sieve to obtain BC-MA@Roxa.

[0020] Optionally, in step (3), the BC-MA@Roxa thin layer obtained in step (2) is spread out and sprayed with gentamicin sulfate aqueous solution in several times, allowed to stand and then pre-frozen, and then freeze-dried and ground to obtain a dual drug carrier.

[0021] Optionally, the mass concentration of the gentamicin sulfate aqueous solution is 50-100 mg / mL; during spraying, the total amount of gentamicin sulfate aqueous solution added is ≤0.2 mL / 100 mg BC-MA@Roxa, and the interval between each spraying is 3-5 min.

[0022] Specifically, in step (3), prepare an aqueous solution of gentamicin sulfate at a concentration of 50-100 mg / mL; spread BC-MA@Roxa in a thin layer, and spray gentamicin solution in small amounts several times, with a total added volume ≤ 0.2 mL / 100 mg BC-MA@Roxa powder. After standing at room temperature for 10 min, pre-freeze at -20°C for 12 h, and freeze-dry in a freezer for 48 h. After removal, grind to obtain BC-MA@Roxa@Genta.

[0023] Preferably, the freeze-drying vacuum degree is 2 Pa, the drying temperature is -40℃, and the drying time is 48 h; the particle size of the dual-drug carrier after grinding is adapted to the particle size of PMMA bone cement powder, both being 50-100 μm.

[0024] In this application, roxadustat is first impregnated in BC-MA channels and dried (embedded and adsorbed into the internal pores), and then a high concentration of gentamicin is sprayed onto the surface and freeze-dried to form a spatial distribution of "inner encapsulated angiotensin-promoting drug + surface antibacterial drug". This achieves rapid release of high concentration of gentamicin on the surface to inhibit early infection, while roxadustat is slowly and continuously released inside to promote local vascularization and tissue repair.

[0025] Among them, the three-dimensional nanofiber network of BC-MA and the porous structure formed by freeze-drying provide a large number of adsorption sites and capillary structures, allowing small molecules (Roxadustat) to enter and be immobilized, exhibiting slow diffusion-controlled release. Gentamicin, through spray-coating freeze-drying, is mainly distributed on the particle surface or near-surface pores, with a high initial release rate. Subsequently, the surface drug is depleted, while the internal drug continues to maintain medium- to long-term effects. Deeply deposited roxadustat is gradually released with the slow degradation of BC-MA, continuously promoting angiogenesis.

[0026] Optionally, in step (4), the amount of the dual-drug carrier added to the polymethyl methacrylate bone cement powder is 0.5-2 wt%. By limiting the addition ratio of the dual-drug carrier, a balance between bioactivity and mechanical properties can be achieved, simultaneously meeting the dual clinical needs for function and mechanical properties.

[0027] Specifically, in step (4), BC-MA@Roxa@Genta and PMMA bone cement powder are dry-mixed at a ratio of 0.5-2wt% for 1-2 min; then, commercially available bone cement-compatible MMA mixture (containing DMPT / TEMA) is added, and after rapid and uniform mixing within 60 s, it is poured into a mold for molding.

[0028] Among them, PMMA bone cement manufacturers recommend a powder-to-liquid ratio of 2.5:1 (solid phase powder: liquid phase monomer liquid).

[0029] According to another aspect of this application, a dual-effect composite bone cement that promotes angiogenesis and has antibacterial properties is also disclosed, which is prepared by the above-described preparation method.

[0030] The beneficial effects of this application include, but are not limited to: 1. This application introduces methacryloyl groups on the surface of bacterial cellulose, enabling it to copolymerize and chemically crosslink with PMMA monomers during polymerization, significantly improving the interfacial bonding strength between the two phases and avoiding problems such as delamination and debonding that are prone to occur in traditional physical blending systems, thereby improving the overall structural stability and mechanical properties of composite bone cement.

[0031] 2. This application achieves effective loading and sustained release of angiotensin-promoting drugs. By loading the angiotensin-promoting drug Roxadustat into modified bacterial cellulose, the adsorption of the three-dimensional porous structure and surface functional groups is utilized to achieve efficient fixation and slow release of the drug, which helps to continuously promote angiogenesis at the implantation site, improve local microcirculation, and enhance tissue repair and regeneration capabilities.

[0032] 3. This application further combines gentamicin sulfate with angiotensin-releasing drugs to achieve synergistic sustained release of antibacterial drugs. This can effectively inhibit bacterial infection in the early stage of implantation, reduce the risk of postoperative infection, and maintain a local sterile environment, providing a good biological basis for bone repair. Attached Figure Description

[0033] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 The fracture surface SEM morphology of the BC-MA@Roxa@Gent / PMMA composite bone cement prepared in Example 1 of this application; Figure 2 This describes the cell adhesion state of the BC-MA@Roxa@Gent / PMMA composite bone cement prepared in Example 1 of this application; Figure 3 The image shows a commercially available PMMA bone cement product (PMMA powder + MMA liquid mixture) used in this application. Figure 4 This is a diagram of the composite bone cement mechanical property testing device used in Experiment Example 4 of this application. Detailed Implementation

[0034] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods in the art or as per the product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described in this patent are for illustrative purposes only.

[0036] In this application, PMMA bone cement (including PMMA powder and MMA mixture) is a commercially available product (spinal bone cement, MT-V, Shandong Mingde Biomedical Engineering Co., Ltd.), bacterial cellulose (product description: BC is a fibrous nanomaterial with an ultra-high aspect ratio obtained by bio-fermentation of acetic acid bacteria using sugars as raw materials. The fiber diameter is 20~50nm, the length is greater than 30um, and the water absorption rate is about 200 times, Guilin Qihong Technology Co., Ltd.), methacrylic anhydride (CAS No.: 760-93-0, molecular weight: 154.16, purity ≥94%, Aladdin), roxadustat (CAS No.: 2043026-13-5, molecular weight: 357.37, purity ≥98%, Aladdin), and gentamicin sulfate (CAS No.: 1405-41-0, molecular weight: 575.67, purity ≥99.9%, Aladdin).

[0037] Example 1 The preparation method of the angiogenic and antibacterial dual-effect composite bone cement includes the following steps: (1) 1.0 g of bacterial cellulose powder was dispersed in 65 mL of anhydrous N,N-dimethylformamide. 0.5 mL of methacrylic anhydride and an equimolar amount of triethylamine were added dropwise while stirring in an ice bath at 3 °C. The temperature was then raised to 40 °C and stirred for 3 h (protected from light and anhydrous throughout). After the reaction was complete, the mixture was washed thoroughly with ethanol and deionized water until neutral, and then dried under vacuum at 45 °C to constant weight to obtain BC-MA.

[0038] (2) Prepare a Roxadustat (FG-4592) solution of 0.4 mg / mL in 20-30% (v / v) ethanol / water; completely immerse BC-MA in the solution and let it stand at room temperature (25℃) in the dark for 24 h. Discard the supernatant, dry in a vacuum oven at 40℃ for 4 h, grind and pass through a 150-mesh sieve to obtain BC-MA@Roxa.

[0039] (3) Prepare a 65 mg / mL gentamicin sulfate aqueous solution; spread BC-MA@Roxa thin layer, spray gentamicin solution in small amounts several times, with a total liquid volume of 0.2 mL / 100 mg BC-MA@Roxa powder. After standing at room temperature for 10 min, pre-freeze at -20 °C for 12 h, and freeze-dry in a freezer for 48 h. After taking it out, grind it to obtain BC-MA@Roxa@Genta.

[0040] (4) Mix BC-MA@Roxa@Genta with PMMA bone cement powder at a ratio of 1.0wt% and dry mix for 2 min; then add MMA mixture (containing DMPT / TEMA), stir quickly and evenly within 60s, and pour into a mold to form a vascular-promoting and antibacterial dual-effect composite bone cement.

[0041] Figure 1The fracture morphology of Example 1 shows that BC-MA fibers form a continuous cross-linked structure within the PMMA matrix, with tight interfacial bonding and no obvious delamination or voids. This indicates that BC-MA and PMMA undergo effective copolymerization after modification with methacrylic anhydride. This structure forms a uniform reinforcing phase during polymerization, significantly improving stress transfer and interfacial bonding, resulting in a fibrous tear morphology at the fracture surface. The dispersion and three-dimensional network structure of BC-MA further enhance the matrix density and load-bearing capacity, thereby effectively improving the compressive strength of the material. Figure 2 The image shows the cell adhesion morphology of Example 1. Numerous cells are observed to be evenly distributed and fully spread on the surface of the composite bone cement, exhibiting intact cell morphology and good extensibility. The results indicate that this composite bone cement possesses excellent cell adhesion properties, providing a favorable interfacial environment for cell growth and osteogenic differentiation.

[0042] Examples 2-4, Comparative Example 1 The difference between Examples 2-4 and Comparative Example 1 and Example 1 lies in the ratio of bacterial cellulose to anhydrous N,N-dimethylformamide; all other aspects are the same.

[0043] In Example 2, the BC:MA ratio was 1.0g:50mL; in Example 3, the BC:MA ratio was 1.0g:85mL; in Example 4, the BC:MA ratio was 1.0g:100mL; and in Comparative Example 1, the BC:MA ratio was 1.0g:0mL.

[0044] Experimental Example 1 The bone cement prepared in Examples 1-4 and Comparative Example 1 was subjected to compression performance tests, and the experimental methods are as follows: According to the YY0459—2003 standard "Acrylic Resin Bone Cement for Surgical Implants", the bone cement mixture and testing equipment were equilibrated at (23±1)℃ for 2 hours before the test, and the entire test process was completed under this temperature condition. After the powder and liquid were mixed, the bone cement was injected into a stainless steel mold using a syringe during the dough stage. After molding, the end plate was fixed to the mold with a clamp to keep it in a tight state, and it was left to stand for about 1 hour to ensure complete solidification. Then the clamp and end plate were removed, and the sample was taken out with a demolding rod, resulting in a cylinder with a length of (12±0.1) mm and a diameter of (6±0.1) mm. The top and bottom ends of the sample were lightly sanded with 400-grit sandpaper until smooth. Finally, a compression test was performed at a constant crosshead speed of up to 20 mm / min, and the load-deformation curve was recorded until the sample failed. The compressive strength (σc) of the sample was calculated using the formula σc = F / A, where F is the maximum load (N) recorded in the compression test, and A is the original cross-sectional area (mm²) of the sample.

[0045] The experimental results are shown in Table 1.

[0046] Table 1. Effect of BC to MA ratio on the compressibility of bone cement

[0047] The results above show that when the ratio of BC to DMF is controlled within the range of 1.0g:50-100mL as specified in this application, the compressive strength of the composite bone cement is significantly better than that of Comparative Example 1 without DMF. Furthermore, the optimal mechanical properties can be achieved within this range by optimizing the ratio (e.g., 1.0g:65mL).

[0048] Examples 5-7, Comparative Example 2 Examples 5-7 and Comparative Example 2 differ from Example 1 in the concentration of roxadustat; all other aspects are the same.

[0049] In Example 5, the concentration of Roxadustat was 0.2 mg / mL; in Example 6, the concentration of Roxadustat was 0.8 mg / mL; in Example 7, the concentration of Roxadustat was 1.0 mg / mL; and in Comparative Example 2, the concentration of Roxadustat was 0 mg / mL.

[0050] Experiment Example 2 The bone cement prepared in Examples 5-7 and Comparative Example 2 was subjected to HUVEC pro-angiogenic gene KDR expression experiments.

[0051] The experimental methods are as follows: This study evaluated the effect of different concentrations of Roxadustat-doped PMMA bone cement on the expression of the pro-angiogenic gene KDR in human umbilical vein endothelial cells (HUVECs) using a model of direct co-culture of bone cement samples and cells. All samples were sterilized by UV light and placed in 24-well plates, inoculated with HUVEC cells, and co-cultured for 24 and 72 hours. After culture, the cells co-cultured with the samples were collected, and total RNA was extracted using the TRIzol method, followed by reverse transcription to synthesize cDNA. The mRNA expression level of the KDR gene was detected by real-time quantitative PCR, with GAPDH as an internal reference gene, and the relative expression level of the KDR gene in different experimental groups was calculated using the 2^(-ΔΔCt) method.

[0052] The experimental results are shown in Table 2.

[0053] Table 2. Effects of Roxadustat concentration on the expression of the pro-angiogenic gene KDR in HUVECs

[0054] The results show that in Comparative Example 2 (0.0 mg / mL), KDR relative expression was 1.00 at baseline, with no pro-angiogenic effect. In Examples 5-7 (0.2-1.0 mg / mL, within the range specified in this application), KDR expression was higher than the control, with Example 1 (0.4 mg / mL) reaching a peak of 2.08, exhibiting the best pro-expression effect. Although KDR expression decreased (1.63-1.12) when the concentration was subsequently increased to 0.8-1.0 mg / mL, it still exceeded the control. These results indicate that the concentration range of roxadustat (0.1-1.0 mg / mL) specified in this application can effectively activate pro-angiogenic genes.

[0055] Examples 8-10, Comparative Example 3 The difference between Examples 8-10 and Comparative Example 3 and Example 1 is the concentration of gentamicin sulfate (Genta), while all other aspects are the same.

[0056] In Example 8, the concentration of gentamicin sulfate (Genta) was 50 mg / mL; in Example 9, the concentration of gentamicin sulfate (Genta) was 85 mg / mL; in Example 10, the concentration of gentamicin sulfate (Genta) was 100 mg / mL; and in Comparative Example 3, the concentration of gentamicin sulfate (Genta) was 0 mg / mL.

[0057] Experimental Example 3 The antibacterial properties of the bone cement prepared in Examples 8-10 and Comparative Example 3 were tested.

[0058] The experimental method is as follows: The antibacterial properties of bone cement samples were determined according to GB / T 38483—2020 "Determination of Antibacterial Activity of Secondary Metabolites of Microbial Antibiotics - Inhibition Zone Method". Staphylococcus aureus was selected as the test strain. The activated bacterial solution was evenly spread on the surface of LB agar plates. After the culture medium solidified, sterilized bone cement discs (6 mm in diameter) were placed flat in the center of the plate and gently pressed to ensure full contact. After incubation at 37±1℃ for 12-18 hours, the samples were removed, and the diameter of the inhibition zone formed around the sample was observed and measured to evaluate its antibacterial activity.

[0059] The experimental results are shown in Table 3.

[0060] Table 3. Effect of Genta Concentration on Antibacterial Properties

[0061] As shown in Table 3, Comparative Example 3 (0 mg / mL) had an inhibition zone diameter of only 6.0 mm (no effective inhibition zone), indicating no antibacterial effect. Examples 8-10 (50-100 mg / mL, the range defined in this application) all formed effective inhibition zones, and the diameter of the inhibition zone gradually increased with increasing Genta concentration (15.2 mm at 50 mg / mL → 20.3 mm at 100 mg / mL). Among them, Example 1 (65 mg / mL) achieved an inhibition zone of 18.4 mm, which meets the clinical antibacterial requirements. These results verify that the Genta concentration range (50-100 mg / mL) defined in this application can achieve effective antibacterial activity.

[0062] Examples 11-13, Comparative Example 4 The difference between Examples 11-13 and Comparative Example 4 and Example 1 lies in the proportion of BC-MA@Roxa@Gent in the powder; all other aspects are the same.

[0063] In Example 11, BC-MA@Roxa@Gent accounted for 0.5 wt% of the PMMA powder; in Example 12, BC-MA@Roxa@Gent accounted for 1.5 wt% of the PMMA powder; in Example 13, BC-MA@Roxa@Gent accounted for 2.0 wt% of the PMMA powder; and in Comparative Example 4, BC-MA@Roxa@Gent accounted for 0 wt% of the powder.

[0064] Experiment Example 4 Mechanical property tests were conducted on the bone cement prepared in Examples 11-13 and Comparative Example 4.

[0065] The experimental method is as follows: Based on the YY0459—2003 standard "Acrylic Resin Bone Cement for Surgical Implants", the bone cement mixture and testing equipment were equilibrated at (23±1)℃ for 2 hours before the test, and the entire testing process was completed under the same temperature conditions. After mixing the powder and liquid, the bone cement was injected into a stainless steel mold using a syringe during the dough stage. After molding, the end plate was fixed to the mold with clamps to maintain a tight seal, and left to stand for about 1 hour to ensure full solidification. Then, the clamps and end plates were removed, and the sample was taken out using a demolding rod, resulting in a rectangular sample with dimensions of (75±0.1) mm × (10±0.1) mm × (3.3±0.1) mm. The edges and top surface of the sample were gently sanded with 400-grit sandpaper to achieve standard dimensions and prevent bending of the bottom surface. A universal testing machine was used, with a constant crosshead rate of 5 mm / min, starting from zero load, and the load-deflection curve was recorded until the sample fractured. Bending toughness was evaluated by calculating the area under the load-deflection curve (i.e., fracture work).

[0066] The experimental results are shown in Table 4.

[0067] Table 4. Effect of the proportion of BC-MA@Roxa@Gent in the powder on mechanical properties

[0068] As shown in Table 4, Comparative Example 4 (0 wt%) exhibited a compressive strength of 85 MPa and a toughness of 0.0563 MJ / m³. In Examples 11-13 (0.5-2.0 wt%, within the range defined in this application), the mechanical properties showed a trend of "first increasing and then decreasing," with Example 1 (1.0 wt%) achieving the best results (compressive strength 88.7 MPa, toughness 0.0670 MJ / m³), significantly superior to the control. Even though the performance of Example 13 (2.0 wt%) decreased slightly, it was still close to the control level. These results verify that the 0.5-2.0 wt% range defined in this application can effectively optimize mechanical properties.

[0069] In summary, the bone cement prepared by the method specified in this application possesses excellent mechanical properties (compressive strength > 85 MPa, significantly improved toughness), long-lasting antibacterial effect, and continuous angiogenic activity, achieving a synergistic effect of mechanical stability, antibacterial properties, and good bone integration performance, thus meeting the needs of clinical bone repair.

[0070] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a dual-effect composite bone cement that promotes blood vessel growth and has antibacterial properties, characterized in that, Includes the following steps: (1) Bacterial cellulose BC was modified by methacrylylation to obtain modified bacterial cellulose BC-MA with methacrylyl groups on the surface; (2) BC-MA was mixed with a solution containing Roxadustat and dried under vacuum to obtain the drug-loaded material BC-MA@Roxadustat; (3) Spray gentamicin sulfate aqueous solution onto BC-MA@Roxa, freeze-dry and grind to obtain the dual drug carrier BC-MA@Roxa@Genta; (4) The dual-drug carrier BC-MA@Roxa@Genta is mixed with polymethyl methacrylate bone cement powder and MMA mixture is added and stirred and solidified to obtain the angiogenic and antibacterial dual-effect composite bone cement.

2. The preparation method according to claim 1, characterized in that, In step (1), bacterial cellulose is dispersed in anhydrous N,N-dimethylformamide, and methacrylic anhydride and equimolar triethylamine are added dropwise while stirring at low temperature. After heating, the reaction is carried out in the dark. After washing and vacuum drying, modified cellulose BC-MA with methacryloyl groups on the surface is obtained.

3. The preparation method according to claim 2, characterized in that, In step (1), the ratio of bacterial cellulose to anhydrous N,N-dimethylformamide is 1.0 g:(50-100) mL; the degree of substitution of BC-MA is 0.05-0.

20.

4. The preparation method according to claim 2, characterized in that, In step (1), the low temperature is 0-5℃, the heating reaction temperature is 35-40℃, and the reaction time in the dark is 2h-4h; the vacuum drying temperature is 40-50℃ until the material reaches constant weight.

5. The preparation method according to claim 1, characterized in that, In step (2), an ethanol-water solution of roxadustat needs to be prepared. The BC-MA obtained in step (1) is completely immersed in the solution, left to stand in the dark, the supernatant is discarded, and the solution is vacuum dried, ground and sieved to obtain BC-MA@Roxa. The mass concentration of roxadustat in roxadustat solution is 0.1-1.0 mg / mL.

6. The preparation method according to claim 1, characterized in that, In step (3), the BC-MA@Roxa thin layer obtained in step (2) is spread out and sprayed with gentamicin sulfate aqueous solution in several times. After standing, it is pre-frozen, then freeze-dried and ground to obtain the dual drug carrier.

7. The preparation method according to claim 6, characterized in that, The mass concentration of gentamicin sulfate aqueous solution is 50-100 mg / mL.

8. The preparation method according to claim 6, characterized in that, When spraying, the total amount of gentamicin sulfate aqueous solution added should be ≤0.2mL / 100mg BC-MA@Roxa, and the interval between each spraying should be 3-5min.

9. The preparation method according to claim 1, characterized in that, In step (4), the amount of the dual-drug carrier added to the polymethyl methacrylate bone cement powder is 0.5-2 wt%.

10. A dual-effect composite bone cement that promotes blood vessel growth and has antibacterial properties, characterized in that, It is prepared by any of the preparation methods described in claims 1-9.

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