An anti-infective and anti-tumor magnesium alloy and its preparation method

Abstract

This invention discloses an anti-infective and anti-tumor magnesium alloy and its preparation method. The magnesium alloy comprises Sr 0.5%-5%, La 0.1%-1%, Cu 0.2%-2%, Ti 0.5%-1%, O ≤1%, with the balance being Mg and unavoidable impurities. The aforementioned magnesium alloy utilizes an in-situ reaction between O and a portion of magnesium at grain boundaries to spontaneously induce the formation of a connected micro / nano porous network, achieving precise control of the elastic modulus while maintaining high strength and bioactivity. Further micro-arc oxidation treatment forms a connected porous oxide film on the surface, which controllably releases various functional ions during degradation. The anti-infective and anti-tumor functions are achieved through the synergistic effect of these multiple ions.

Description

Technical Field

[0001] This invention relates to the field of medical materials technology, and in particular to an anti-infective and anti-tumor magnesium alloy and its preparation method. Background Technology

[0002] Tumors and postoperative infections have always been challenging issues in clinical orthopedic surgery, especially in bone defect repair after tumor resection. Implant materials not only need excellent bone repair capabilities but also must simultaneously inhibit tumor recurrence and prevent postoperative wound infection. Traditional treatments typically involve postoperative radiotherapy and chemotherapy to remove residual tumor cells, combined with antibiotics to prevent infection. However, these methods suffer from drawbacks such as significant systemic toxicity, insufficient local drug concentrations, and the potential to induce drug-resistant bacteria. Furthermore, commonly used non-degradable implant materials, such as titanium alloys and stainless steel, only provide mechanical support and lack active anti-infection and anti-tumor functions. They also require a second surgery for removal, increasing patient suffering and the medical burden.

[0003] Biodegradable magnesium alloys, as a new generation of medical metallic materials, have become a research hotspot in the field of bone implants due to their advantages, such as a Young's modulus similar to that of natural human bone tissue, complete in vivo degradation and absorption, and the ability of magnesium ions, a degradation product, to promote osteogenesis. Recent studies have further discovered that magnesium hydroxide produced during the in vivo degradation process can alkalize the acidic tumor microenvironment, and the hydrogen gas produced during degradation has antioxidant and anti-inflammatory effects. High concentrations of magnesium ions can also reshape the tumor microenvironment and inhibit cancer cell proliferation, demonstrating natural anti-tumor potential. Simultaneously, some alloying elements themselves possess good antibacterial activity, providing a foundation for developing integrated implant materials that combine anti-infection, anti-tumor, and osteogenesis-promoting properties.

[0004] While some research reports have been published on anti-tumor magnesium alloys, existing technologies still have several unresolved technical shortcomings: First, the composition design often relies on single functional elements to achieve anti-tumor or anti-infection effects, lacking multi-element synergistic functional design. This makes it difficult to simultaneously balance anti-infection, anti-tumor, mechanical properties, and corrosion resistance. For example, magnesium alloys with only copper added have good antibacterial effects, but their degradation rate is too fast and their mechanical support is insufficient. Magnesium alloys with only rare earth elements added have improved corrosion resistance, but their anti-tumor and anti-infection activities are weak. Second, the functions of existing functional magnesium alloys often rely on surface drug-loaded coatings, which have problems such as poor coating adhesion, easy early detachment, and uncontrollable functional release. This makes it difficult to maintain a local effective drug concentration for a long time after implantation, and cannot meet the clinical needs of long-term inhibition of residual tumor cell recurrence and continuous anti-infection after tumor surgery.

[0005] Therefore, developing a novel anti-infective and anti-tumor biomedical magnesium alloy, achieving synergistic effects of multiple functions through composition design and process optimization, overcoming the shortcomings of existing technologies, and meeting clinical needs has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, one of the objectives of this invention is to provide an anti-infective and anti-tumor magnesium alloy to solve the aforementioned problems of traditional technology.

[0007] The second objective of this invention is to provide a method for preparing the above-mentioned anti-infective and anti-tumor magnesium alloy.

[0008] One of the objectives of this invention is achieved through the following technical solution: A magnesium alloy with anti-infective and anti-tumor properties, its chemical composition by weight percentage includes: The alloy composition is: Sr 0.5%-5%, La 0.1%-1%, Cu 0.2%-2%, Ti 0.5%-1%, O ≤1% (preferably 0.4-1%), with the balance being Mg and unavoidable impurities. The magnesium alloy spontaneously forms a multi-level porous network through the in-situ reaction of some magnesium and O elements, and a porous oxide film is formed on the surface after micro-arc oxidation treatment. The magnesium alloy has an elastic modulus of 14-24 GPa, a yield strength ≥185 MPa, an antibacterial rate ≥90%, an osteosarcoma inhibition rate ≥66%, and an osteoblast survival rate ≥80%.

[0009] In this invention, an in-situ reaction between oxygen and a portion of magnesium at grain boundaries spontaneously induces the formation of a connected micro / nano porous network, achieving precise control of the elastic modulus while maintaining high strength and bioactivity. Further micro-arc oxidation treatment forms a connected porous oxide film on the surface, allowing for the controlled release of various functional ions (such as Mg²⁺) during degradation. + Sr² + Cu² + La³ + This compound achieves anti-infection and anti-tumor functions through the synergistic effect of multiple ions. Specifically, the Mg (magnesium) matrix, as a biodegradable matrix, possesses inherent anti-tumor activity; the alkaline microenvironment generated during degradation inhibits bacterial proliferation, and the degradation products are metabolized by the human body without long-term toxicity; Sr (strontium), on the one hand, inhibits osteoclast activity, promotes osteoblast differentiation, and enhances bone integration; on the other hand, it can regulate the tumor cell cycle, inhibiting tumor cell proliferation and exerting a synergistic anti-tumor effect; Cu (copper), possessing broad-spectrum antibacterial activity, kills pathogenic bacteria by disrupting bacterial cell membranes and inducing reactive oxygen species generation; low concentrations of copper ions can also synergistically inhibit tumor cell proliferation; La (lanthanum), as a rare earth element, refines magnesium alloy grains, improves alloy mechanical strength, regulates alloy corrosion behavior, slows degradation rates, avoids ion burst release, and further enhances the synergistic effect of antibacterial and anti-tumor properties; Ti (titanium), refines grains and improves alloy corrosion resistance.

[0010] Furthermore, the O element is added via TiO2 powder or a pre-alloyed Ti-O master alloy. During vacuum arc melting or vacuum induction melting, TiO2 undergoes a trace reduction reaction with Ti (TiO2 + Ti → 2TiO), and oxygen enters the crystal lattice as interstitial atoms, causing it to react in situ with some magnesium.

[0011] Furthermore, the average pore size of the interconnected multi-level pore network is 100nm-800nm.

[0012] Furthermore, the porosity of the interconnected multi-level pore network is in the range of 30%-55%.

[0013] Furthermore, the porous oxide film has a porosity of 20%-50%, an average pore size of 1μm-10μm, and an oxide film thickness of 10μm-50μm.

[0014] Furthermore, the total content of the unavoidable impurities is ≤0.5wt%, and the content of a single impurity is ≤0.1wt%. Unavoidable impurities are common impurity elements that cannot be completely removed during the metallurgical preparation of titanium alloys. The content is below the requirement and fully complies with the safety requirements for medical implant materials.

[0015] The second objective of this invention is achieved by the following technical solution: A method for preparing an anti-infective and anti-tumor magnesium alloy includes the following steps: S1: Weigh each raw material according to the proportion of raw material composition, and add oxygen through high-purity titanium dioxide powder or pre-alloyed Ti-O master alloy; S2: Place the prepared raw materials in a vacuum melting furnace, evacuate the furnace, and then fill it with argon gas for protection. Repeat the melting process 3-4 times to obtain a uniformly composed ingot; wherein, the vacuum melting process is performed with the vacuum level set to 1×10⁻⁶. -3 Pa below (including 1×10) -3 (Pa), filled with 0.04Mpa-0.06MPa high-purity argon gas for protection, and repeatedly smelted at a temperature of 1600℃-1700℃; In this step, since O is mainly added through TiO2 or Ti-O master alloy, the decomposition temperature of TiO2 is as high as about 1800℃, while the temperature of vacuum casting of titanium alloy is generally 1600℃-1700℃. Since the amount added is small, it is only decomposed gradually. The decomposed O atoms directly and uniformly dissolve into the magnesium matrix or react with some magnesium, and will not overflow in large quantities in the form of gas. After repeated melting 3 to 4 times, it can be completely homogenized and no unmelted particles will appear.

[0016] S3: Hold the ingot at 1050℃-1150℃ for 12~24h to homogenize it and eliminate component segregation during the smelting process, and then air cool it to room temperature. S4: The homogenized ingot is heated to 900℃-1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1-1 vol% oxygen for multi-directional forging, with a total deformation of 60%~70%. It is then air-cooled to obtain a forging billet. The grains are further refined to eliminate casting defects and obtain a uniform forging billet. Oxygen is increased to react with the magnesium matrix during the high-temperature forging process, generating in-situ dispersed nano-sized magnesium oxide particles, which provide precipitation nucleation sites for subsequent aging treatment. After forging, the billet is air-cooled to room temperature. S5: The forged billet undergoes gradient aging heat treatment, and is then cooled to room temperature in the furnace to obtain a magnesium alloy billet. Gradient aging treatment of the forged billet allows Mg and O elements to fully diffuse and segregate to the grain boundaries, undergoing a preliminary reaction that induces uniform nucleation of micropores. Further heat treatment promotes the full reaction of Mg-O to generate MgO, accompanied by the volatilization of trace amounts of Mg, ultimately forming a connected micro / nano porous network. The gradient aging heat treatment consists of three steps: First, heating to 720℃-800℃ and holding for 2-4 hours; second, further heating to 820℃-880℃ and holding for 4-8 hours; third, slowly cooling to 500℃-600℃ at a rate of 5℃ / h-15℃ / h and holding for 8-12 hours.

[0017] S6: Perform micro-arc oxidation treatment on the magnesium alloy blank, and clean and dry it after treatment to obtain the final product. The micro-arc oxidation treatment steps are as follows: use the magnesium alloy blank as the anode and the stainless steel plate as the cathode, and perform micro-arc oxidation treatment in a silicate-phosphate electrolyte. The treatment voltage is 300V-500V, and the treatment time is 5min-30min. The silicate-phosphate electrolyte contains, by concentration: sodium silicate 10g / L-20g / L, sodium phosphate 5g / L-10g / L, and sodium hydroxide 2g / L-5g / L. The temperature of the silicate-phosphate electrolyte is controlled at 20℃-40℃.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The magnesium alloy of the present invention utilizes the in-situ reaction of O element and some magnesium element at the grain boundary to spontaneously induce the formation of a connected micro-nano pore network, thereby achieving precise control of elastic modulus and taking into account both high strength and bioactivity. After micro-arc oxidation treatment, a connected porous oxide film is formed on the surface, which can controllably release a variety of functional ions during the degradation process, and achieve anti-infection and anti-tumor functions through the synergistic effect of multiple ions.

[0019] 2. The magnesium alloy of the present invention achieves stable control of the degradation rate at 0.2-0.8 mm / year through triple regulation of composition optimization, gradient aging to regulate microstructure, and micro-arc oxidation surface modification. This avoids the problems of excessively rapid degradation and ion burst release of traditional magnesium alloys, and realizes the long-term stable release of functional ions. While achieving high antibacterial rate and high tumor inhibition rate, it has no obvious toxicity to normal osteoblasts and has good prospects for clinical application.

[0020] 3. The magnesium alloy of the present invention is pre-oxygenated by TiO2 or Ti-O master alloy, and low-concentration oxygen is added in situ during the forging process to generate nano-magnesium oxide, which not only ensures the uniform distribution of oxygen, but also avoids the porosity defects caused by a large amount of gas overflow during the melting process. Detailed Implementation

[0021] The present invention will now be further described in conjunction with specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0022] Example 1 A magnesium alloy with anti-infective and anti-tumor properties, its chemical composition by weight percentage includes: Sr 0.5wt%, La 0.1wt%, Cu 0.2wt%, Ti 0.5wt%, O 0.4wt%, balance Mg.

[0023] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-lanthanum master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0024] Example 2 A magnesium alloy with anti-infective and anti-tumor properties, its chemical composition by weight percentage includes: Sr 1wt%, La 0.3wt%, Cu 0.5wt%, Ti 0.6wt%, O 0.5wt%, balance Mg.

[0025] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-lanthanum master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0026] Example 3 A magnesium alloy with anti-infective and anti-tumor properties, its chemical composition by weight percentage includes: Sr 2wt%, La 0.5wt%, Cu 0.8wt%, Ti 0.7wt%, O 0.6wt%, balance Mg.

[0027] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-lanthanum master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0028] Example 4 A magnesium alloy with anti-infective and anti-tumor properties, its chemical composition by weight percentage includes: Sr 3wt%, La 0.8wt%, Cu 1.5wt%, Ti 0.8wt%, O 0.7wt%, balance Mg.

[0029] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-lanthanum master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0030] Example 5 A magnesium alloy with anti-infective and anti-tumor properties, its chemical composition by weight percentage includes: Sr 4wt%, La 0.9wt%, Cu 1.8wt%, Ti 0.9wt%, O 0.8wt%, balance Mg.

[0031] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-lanthanum master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0032] Example 6 A magnesium alloy with anti-infective and anti-tumor properties, its chemical composition by weight percentage includes: Sr 5wt%, La 1wt%, Cu 2wt%, Ti 1wt%, O 1wt%, balance Mg.

[0033] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-lanthanum master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0034] Comparative Example 1 Unlike Example 3, the magnesium alloy in Comparative Example 1 did not contain Sr (Sr=0), but the remaining components and steps were the same as in Example 3, and will not be repeated here.

[0035] That is: a magnesium alloy with anti-infective and anti-tumor properties, whose chemical composition by mass percentage includes: La 0.5 wt%, Cu 0.8 wt%, Ti 0.7 wt%, O 0.6 wt%, balance Mg.

[0036] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-lanthanum master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder as raw materials according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0037] Comparative Example 2 Unlike Example 3, the magnesium alloy in Comparative Example 2 did not contain Cu (Cu=0), but the remaining components and steps were the same as in Example 3, and will not be repeated here.

[0038] That is: a magnesium alloy with anti-infective and anti-tumor properties, whose chemical composition by mass percentage includes: Sr 2wt%, La 0.5wt%, Ti 0.7wt%, O 0.6wt%, balance Mg.

[0039] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-lanthanum master alloy, magnesium-titanium master alloy, and titanium dioxide powder according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0040] Comparative Example 3 Unlike Example 3, the magnesium alloy in Comparative Example 3 did not contain La (La=0), but the remaining components and steps were the same as in Example 3, and will not be repeated here.

[0041] That is: a magnesium alloy with anti-infective and anti-tumor properties, whose chemical composition by mass percentage includes: Sr 2wt%, Cu 0.8wt%, Ti 0.7wt%, O 0.6wt%, balance Mg.

[0042] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder as raw materials according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0043] Comparative Example 4 Unlike Example 3, the magnesium alloy in Comparative Example 4 omits the gradient aging heat treatment in step S5, and proceeds directly from forging to the micro-arc oxidation treatment in step S6. The remaining components and steps are the same as in Example 3, and will not be repeated here.

[0044] That is: a magnesium alloy with anti-infective and anti-tumor properties, whose chemical composition by mass percentage includes: Sr 2wt%, La 0.5wt%, Cu 0.8wt%, Ti 0.7wt%, O 0.6wt%, balance Mg.

[0045] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium strontium master alloy, magnesium lanthanum master alloy, magnesium copper master alloy, magnesium titanium master alloy, and titanium dioxide powder as raw materials according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Micro-arc oxidation treatment: The forged billet is used as the anode and the stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set at 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the magnesium alloy finished product.

[0046] Comparative Example 5 Unlike Example 3, the micro-arc oxidation treatment in step S6 was omitted in the preparation steps of the magnesium alloy in Comparative Example 5. The remaining components and steps are the same as in Example 3, and will not be repeated here.

[0047] That is: a magnesium alloy with anti-infective and anti-tumor properties, whose chemical composition by mass percentage includes: Sr 2wt%, La 0.5wt%, Cu 0.8wt%, Ti 0.7wt%, O 0.6wt%, balance Mg.

[0048] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-lanthanum master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1 vol% oxygen for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain the final product.

[0049] Comparative Example 6 Unlike Example 3, the multi-directional forging step in the preparation of the magnesium alloy in Comparative Example 5 was carried out in an argon protective atmosphere. The remaining components and steps were the same as in Example 3, and will not be repeated here.

[0050] That is: a magnesium alloy with anti-infective and anti-tumor properties, whose chemical composition by mass percentage includes: Sr 2wt%, La 0.5wt%, Cu 0.8wt%, Ti 0.7wt%, O 0.6wt%, balance Mg.

[0051] The preparation steps of this magnesium alloy are as follows: S1: Melting and Casting: Weigh magnesium ingots, magnesium-strontium master alloy, magnesium-lanthanum master alloy, magnesium-copper master alloy, magnesium-titanium master alloy, and titanium dioxide powder according to the above composition ratio, place them in a vacuum induction furnace, and evacuate to 1×10⁻⁶. -3 After Pa, 0.04 MPa of high-purity argon gas is introduced, and the mixture is heated to 1600℃ for melting and casting. The melting is repeated 4 times to ensure uniform composition and obtain alloy ingots. S2: Homogenization treatment: Heat the ingot to 1100℃ and hold for 12 hours to eliminate component segregation during the smelting process, then air cool to room temperature; S3: Multi-directional forging: The homogenized ingot is heated to 1000℃ in an argon protective atmosphere for multi-directional forging, and the total deformation is controlled to be 65%. After forging, the forging billet is obtained by air cooling. S4: Gradient aging heat treatment: The forging billet is subjected to a three-step gradient aging treatment: the first step is to heat up to 720℃ and hold for 2 hours; the second step is to continue heating to 880℃ and hold for 4 hours; the third step is to slowly cool down to 500℃ at a rate of 5℃ / h and hold for 8 hours, and finally cool to room temperature with the furnace to obtain a magnesium alloy billet. S5: Micro-arc oxidation treatment: Magnesium alloy blank is used as the anode and stainless steel plate is used as the cathode. The electrolyte contains 15g / L sodium silicate, 8g / L sodium phosphate and 3g / L sodium hydroxide. The electrolyte temperature is controlled at 30℃, the treatment voltage is set to 400V, the treatment time is 15min, and the oxide film thickness is controlled at 20μm. After the treatment, the product is washed with deionized water and dried to obtain the finished magnesium alloy.

[0052] Performance testing: 1. Porosity and average pore size of porous oxide films, and porosity and average pore size of interconnected multi-level pore networks: Porosity was tested using the Archimedes drainage method, and the average pore size was statistically analyzed using scanning electron microscopy.

[0053] 2. Degradation rate: The immersion loss method was used for testing, and the calculation formula is: Degradation rate (mm / year) = 8.76 × 10⁻⁶ 4 ×ΔW / (A×t×ρ), where ΔW is the weight loss, A is the sample area, t is the immersion time, and ρ is the alloy density.

[0054] 3. Mechanical properties: Compressive yield strength and elastic modulus were tested in accordance with GB / T 7314-2017 "Metallic materials - Compression test at room temperature".

[0055] 4. Antibacterial properties: The inhibition rate against Staphylococcus aureus was tested using the plate count method.

[0056] 5. Antitumor properties: The inhibition rate of human osteosarcoma cell proliferation after 72 hours of culture was tested using the CCK-8 assay.

[0057] 6. Cell compatibility: The cell viability of normal osteoblasts after 72 hours of culture was tested using the CCK-8 assay.

[0058] 7. Coating thickness: Tested according to GB / T 6462-2005 "Measuring the thickness of metal and oxide coatings by microscopy".

[0059] 8. The test results are shown in Table 1 and Table 2 below.

[0060] Table 1 Table 2 The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A magnesium alloy with anti-infective and anti-tumor properties, characterized in that, Its chemical composition, by mass percentage, includes: Sr 0.5%-5%, La 0.1%-1%, Cu 0.2%-2%, Ti 0.5%-1%, O ≤1%, with the balance being Mg and unavoidable impurities. Among them, the magnesium alloy spontaneously forms a connected multi-level porous network through the in-situ reaction of some magnesium and O elements, and a porous oxide film is formed on the surface after micro-arc oxidation treatment. The magnesium alloy has an elastic modulus of 14-24 GPa, a yield strength ≥185 MPa, an antibacterial rate ≥90%, an osteosarcoma inhibition rate ≥66%, and an osteoblast survival rate ≥80%.

2. The anti-infective and anti-tumor magnesium alloy according to claim 1, characterized in that, The O element is added by means of TiO2 powder or pre-alloyed Ti-O master alloy.

3. The anti-infective and anti-tumor magnesium alloy according to claim 1, characterized in that, The porosity of the interconnected multi-level pore network is in the range of 30%-55%.

4. The anti-infective and anti-tumor magnesium alloy according to claim 1, characterized in that, The porous oxide film has a porosity of 20%-50% and an average pore size of 1μm-10μm.

5. A method for preparing an anti-infective and antitumor magnesium alloy as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Weigh each raw material according to the proportion of raw material composition, and add oxygen through high-purity titanium dioxide powder or pre-alloyed Ti-O master alloy; S2: Place the prepared raw materials in a vacuum melting furnace, evacuate the furnace, fill it with argon gas for protection, and melt it repeatedly 3 to 4 times to obtain a casting with uniform composition. S3: Hold the ingot at 1050℃-1150℃ for 12~24h to homogenize it and eliminate component segregation during the smelting process, and then air cool it to room temperature; S4: The homogenized ingot is heated to 900℃-1000℃ in an argon-oxygen mixed protective atmosphere containing 0.1-1 vol% oxygen for multi-directional forging, with a total deformation of 60%~70%, and then air-cooled to obtain the forging billet. S5: The forging billet is subjected to gradient aging heat treatment and then cooled to room temperature in the furnace to obtain a magnesium alloy billet. S6: Perform micro-arc oxidation treatment on the magnesium alloy blank, and clean and dry it after the treatment to obtain the final product.

6. The method for preparing the anti-infective and anti-tumor magnesium alloy according to claim 5, characterized in that, In step S2, the vacuum melting process is evacuated to 1×10⁻⁶. -3 Below Pa, it is protected by 0.04MPa-0.06MPa high-purity argon gas, and the temperature for repeated melting is 1600℃-1700℃.

7. The method for preparing the anti-infective and anti-tumor magnesium alloy according to claim 5, characterized in that, In step S5, the gradient aging heat treatment is divided into three steps: First, heat up to 720℃-800℃ and hold for 2h-4h; Second, continue to heat up to 820℃-880℃ and hold for 4h-8h; Third, slowly cool down to 500℃-600℃ at a rate of 5℃ / h-15℃ / h and hold for 8h-12h.

8. The method for preparing the anti-infective and anti-tumor magnesium alloy according to claim 5, characterized in that, In step S6, the micro-arc oxidation process is as follows: using a magnesium alloy blank as the anode and a stainless steel plate as the cathode, micro-arc oxidation is performed in a silicate-phosphate electrolyte.

9. The method for preparing the anti-infective and anti-tumor magnesium alloy according to claim 8, characterized in that, The micro-arc oxidation process uses a processing voltage of 300V-500V and a processing time of 5min-30min.

10. The method for preparing the anti-infective and anti-tumor magnesium alloy according to claim 8, characterized in that, The silicate-phosphate electrolyte comprises, by concentration: 10g / L-20g / L sodium silicate, 5g / L-10g / L sodium phosphate, and 2g / L-5g / L sodium hydroxide. The temperature of the silicate-phosphate electrolyte is controlled between 20℃ and 40℃.

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