Medical magnesium alloy and preparation method thereof

Abstract

The present application relates to the technical field of medical magnesium alloy, and particularly relates to a medical magnesium alloy and a preparation method thereof. Although magnesium metal has similar elastic modulus and antibacterial performance to natural bone, its degradation speed in a physiological environment is too fast to hinder its clinical application. Based on the above problem, the present application provides a medical magnesium alloy containing Mg, Ga, Sr, Zn and other elements in its composition, which can not only reduce the degradation rate of the metal Mg in the physiological environment, but also significantly improve the antibacterial performance thereof, and is very beneficial to promoting the clinical application of the magnesium alloy.

Description

Technical Field

[0001] This invention relates to the field of medical magnesium alloy technology, and in particular to a medical magnesium alloy and its preparation method. Background Technology

[0002] Bone implants are important biomedical materials used in bone repair and orthopedic surgery, including bone plates and screws. Currently, the most commonly used bone implant materials in clinical practice are stainless steel, cobalt alloys, and titanium alloys. These materials have good corrosion resistance and can remain stably in the human body for a long time. However, because of this, they often need to be removed a second time, placing a double burden on patients both physically and financially.

[0003] Magnesium (Mg) has mechanical properties remarkably similar to those of human bone. As a bone implant material, magnesium is biodegradable and absorbable, eliminating the pain and financial burden of secondary surgery for patients and preventing other complications caused by long-term implantation. Studies have shown that while magnesium possesses similar elastic modulus and antibacterial properties to natural bone, its rapid degradation in physiological environments hinders its clinical application. To reduce the degradation rate of Mg and match it to bone healing time, researchers commonly employ alloying methods. While this method improves the corrosion resistance of bone graft materials, it reduces their antibacterial activity, making the grafts more susceptible to infection, which is highly detrimental to the success of bone transplantation. Summary of the Invention

[0004] In view of the problems existing in the prior art, the technical problem to be solved by the present invention is that although magnesium metal has an elastic modulus and antibacterial properties similar to natural bone, its degradation rate in the physiological environment is too fast, which hinders its clinical application.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: This invention provides a medical magnesium alloy, which, by weight percentage, comprises the following components:

[0006]

[0007] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0008] Specifically, the medical magnesium alloy comprises the following components by weight percentage:

[0009]

[0010] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0011] Specifically, the raw materials for the medical magnesium alloy are pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy, and Mg-Zr master alloy.

[0012] Specifically, the medical magnesium alloy is prepared according to the following steps:

[0013] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Zr master alloy are mixed to obtain mixed raw materials;

[0014] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 750-760℃, keep warm for 25-30 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a rectangular mold at 250℃ and let it cool naturally to room temperature to obtain the product.

[0015] Specifically, the heating rate in step (2) is 3-5℃.

[0016] The beneficial effects of this invention are:

[0017] (1) The present invention prepared a magnesium alloy. Through experiments, it was found that adding Ga, Sr and Zn to the metal Mg can significantly improve the corrosion rate and antibacterial effect of the magnesium alloy.

[0018] (2) Further research found that adding Mn metal elements with grain-refining effect to the magnesium alloy Mg-Ga-Sr-Zn can not only further reduce the corrosion rate of the magnesium alloy, but also further improve the antibacterial effect of medical magnesium alloy. Compared with adding other grain-refining metal elements (such as Ca, Y, etc.), the effect is better. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the embodiments.

[0020] Example 1

[0021] Medical-grade magnesium alloys, by weight percentage, include the following components:

[0022]

[0023] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0024] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Zr master alloy are mixed to obtain mixed raw materials;

[0025] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 750°C, the heating rate is 3°C, keep warm for 25 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a rectangular mold with dimensions of 15mm×15mm×3mm at 250°C, and cool naturally to room temperature to obtain medical magnesium alloy.

[0026] Example 2

[0027] Medical-grade magnesium alloys, by weight percentage, include the following components:

[0028]

[0029] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0030] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Zr master alloy are mixed to obtain mixed raw materials;

[0031] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 760°C, the heating rate is 3°C, keep warm for 30 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a rectangular mold with dimensions of 15mm×15mm×3mm at 250°C, and cool naturally to room temperature to obtain medical magnesium alloy.

[0032] Example 3

[0033] Medical-grade magnesium alloys, by weight percentage, include the following components:

[0034]

[0035] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0036] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Zr master alloy are mixed to obtain mixed raw materials;

[0037] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 760°C, the heating rate is 5°C, keep warm for 25 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a rectangular mold with dimensions of 15mm×15mm×3mm at 250°C, and cool naturally to room temperature to obtain medical magnesium alloy.

[0038] Example 4

[0039] Medical-grade magnesium alloys, by weight percentage, include the following components:

[0040]

[0041] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0042] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Zr master alloy are mixed to obtain mixed raw materials;

[0043] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 755°C, the heating rate is 5°C, keep warm for 30 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a rectangular mold with dimensions of 15mm×15mm×3mm at 250°C, and let it cool naturally to room temperature to obtain the product.

[0044] Example 5

[0045] Medical-grade magnesium alloys, by weight percentage, include the following components:

[0046]

[0047]

[0048] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0049] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Zr master alloy are mixed to obtain mixed raw materials;

[0050] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 750°C, the heating rate is 3°C, keep warm for 30 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a rectangular mold with dimensions of 15mm×15mm×3mm at 250°C, and cool naturally to room temperature to obtain medical magnesium alloy.

[0051] Comparative Example 1 is the same as Example 1, except that the medical magnesium alloy in Comparative Example 1, by weight percentage, includes the following components:

[0052]

[0053] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0054] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Ca master alloy are mixed to obtain mixed raw materials;

[0055] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 750°C, the heating rate is 3°C, keep the temperature for 25 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a 15mm×15mm×3mm rectangular mold at 250°C, and cool naturally to room temperature to obtain magnesium alloy.

[0056] Comparative Example 2 is the same as Example 1, except that the medical magnesium alloy in Comparative Example 2, by weight percentage, includes the following components:

[0057]

[0058]

[0059] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0060] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Y master alloy are mixed to obtain mixed raw materials;

[0061] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 750°C, the heating rate is 3°C, keep the temperature for 25 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a 15mm×15mm×3mm rectangular mold at 250°C, and cool naturally to room temperature to obtain magnesium alloy.

[0062] Comparative Example 3 is the same as Example 1, except that the medical magnesium alloy in Comparative Example 3, by weight percentage, includes the following components:

[0063]

[0064] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0065] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Zr master alloy are mixed to obtain mixed raw materials;

[0066] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 750°C, the heating rate is 3°C, keep the temperature for 25 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a 15mm×15mm×3mm rectangular mold at 250°C, and cool naturally to room temperature to obtain magnesium alloy.

[0067] Comparative Example 4 is the same as Example 1, except that the medical magnesium alloy in Comparative Example 4, by weight percentage, includes the following components:

[0068]

[0069]

[0070] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0071] (1) According to the formula amount, pure Mg, pure Zn, pure Ga, pure Sr, Mg-Mn master alloy and Mg-Nd master alloy are mixed to obtain mixed raw materials;

[0072] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 750°C, the heating rate is 3°C, keep the temperature for 25 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a 15mm×15mm×3mm rectangular mold at 250°C, and cool naturally to room temperature to obtain magnesium alloy.

[0073] Comparative Example 5 is the same as Example 1, except that the medical magnesium alloy in Comparative Example 5 is pure Mg.

[0074] Comparative Example 6 is the same as Example 1, except that the medical magnesium alloy in Comparative Example 6, by weight percentage, includes the following components:

[0075] Ga 0.1%

[0076] Sr 0.1%

[0077] Zn 0.5%

[0078] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0079] (1) According to the formula, pure Mg, pure Zn, pure Ga and pure Sr are mixed to obtain mixed raw materials;

[0080] (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 750°C, the heating rate is 3°C, keep the temperature for 25 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a 15mm×15mm×3mm rectangular mold at 250°C, and cool naturally to room temperature to obtain magnesium alloy.

[0081] Comparative Example 7 is the same as Example 1, except that the medical magnesium alloy in Comparative Example 7, by weight percentage, includes the following components:

[0082]

[0083] The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

[0084] Performance testing:

[0085] Magnesium alloy samples obtained in Examples 1-5 and Comparative Examples 1-7 were polished to 2000 grit with silicon carbide paper using tap water as a lubricant, and then rinsed in an ultrasonic bath for 5 minutes with acetone, ethanol (96%), and deionized water, respectively. They were then subjected to autoclaving.

[0086] In vitro degradation rate of magnesium alloy samples: The magnesium alloys obtained in Examples 1-5 and Comparative Examples 1-4 were placed in 3 mL of autoclaved trypsin-soybean soup (TSB) solution and incubated at 37°C, pH 7.4, 95% humidity, and 5% CO2 for 72 hours. After 72 hours, the samples were removed from the TSB, rinsed with deionized water, and then washed with 200 g / L chromic acid, 10 g / L barium nitrate, and 10 g / L silver nitrate for 1 min at room temperature to remove surface degradation products. The samples were dried at room temperature for 12 h, and the washed samples were weighed with an accuracy of 0.1 mg. The in vitro degradation rate C of the magnesium alloy samples in TSB was estimated based on the following calculations:

[0087] C=(M0-M1) / ρAt

[0088] In the above formula, Mo is the average initial mass of the magnesium alloy, M1 is the average mass after soaking for 72 hours and washing, ρ is the material density (water displacement method), A is the base area of ​​the square sample, and t is the soaking time.

[0089] In vitro antibacterial properties of magnesium alloy samples:

[0090] Staphylococcus aureus (ATCC 43300), Escherichia coli (ATCC 25922), and Staphylococcus epidermidis (ATCC 35984) were added to separate 5 mL TSB medium flasks and incubated overnight at 37°C and 220 rpm with shaking. Each bacterium was then inoculated onto sheep blood agar (SBA) plates at 37°C and cultured for 24 h. Single colonies were collected and cultured in 6 mL of autoclaved medium with shaking at 220 rpm for 3 h, producing 1 × 10⁻⁶ cells / mL in TSB solution. 6 One colony-forming unit (CFU) / ml.

[0091] After autoclaving, the magnesium alloy samples obtained in Examples 1-5 and Comparative Examples 1-7 were placed in 6 ml of TSB solution containing three different types of bacteria (12 × 3 = 27 sets of experiments). The colony count of each type of bacteria in the TSB solution was 1 × 10⁻⁶. 6 (CFU) / ml. Three blank tests consisted of 6 ml of TSB solution containing only three different bacteria. Each blank test contained 1×10⁻⁶ CFU / ml of TSB solution. 6Single colony. The test culture was incubated at 37℃ in a humidified incubator with 5% CO2 for 3 days. After 3 days of incubation, the TSB solution of each test group was diluted 10 times, and three copies were prepared and incubated at 37℃ for 24 hours. The number of colonies was then observed.

[0092] The antibacterial rate is calculated using the following formula:

[0093] Antibacterial rate (%) = (BA) / B × 100%.

[0094] A represents the average number of viable bacteria in the culture medium of the implanted magnesium alloy sample, and B represents the average number of viable bacteria in the blank test.

[0095] The specific test results are shown in Table 1.

[0096] Table 1

[0097]

[0098] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A medical magnesium alloy, characterized in that, It contains the following components by weight percentage: Ga 0.1-0.2% Sr 0.1-0.2% Zn 0.5-1% Mn 1-2% The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

2. The medical magnesium alloy according to claim 1, characterized in that, It contains the following components by weight percentage: Ga 0.1% Sr 0.1% Zn 1% Mn 2% The balance is Mg and unavoidable impurities, with the total amount of impurity elements ≤0.1%.

3. A medical magnesium alloy according to claim 1 or 2, characterized in that, The raw materials for the medical magnesium alloy are pure Mg, pure Zn, pure Ga, pure Sr, and Mg-Mn master alloy.

4. A medical magnesium alloy according to claim 3, characterized in that, The medical magnesium alloy is prepared according to the following steps: (1) According to the formula, pure Mg, pure Zn, pure Ga, pure Sr and Mg-Mn master alloy are mixed to obtain mixed raw materials; (2) Place the mixed raw materials in a vacuum dryer, heat the mixed raw materials to 750-760℃, keep warm for 25-30 minutes, stir vigorously once every 5 minutes, and then transfer the melt to a rectangular mold at 250℃ and let it cool naturally to room temperature to obtain the product.

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