CN114369808B

CN114369808B - Method for preparing antibacterial coating on surface of magnesium and magnesium alloy

Info

Publication number: CN114369808B
Application number: CN202111563708.4A
Authority: CN
Inventors: 刘辰; 陈小虎; 韩俊刚; 曹召勋; 赵枢明; 付玉; 王荫洋; 邵志文; 徐永东; 朱秀荣
Original assignee: China Weapon Science Academy Ningbo Branch
Current assignee: China Weapon Science Academy Ningbo Branch
Priority date: 2021-12-20
Filing date: 2021-12-20
Publication date: 2024-02-06
Anticipated expiration: 2041-12-20
Also published as: CN114369808A

Abstract

The invention discloses a method for preparing an antibacterial coating on the surface of magnesium and magnesium alloy, which is characterized by comprising the following preparation steps: mounting a copper target at a target position of double-layer glow plasma infiltration plating equipment, fixing a magnesium/magnesium alloy substrate on a sample table of the double-layer glow plasma infiltration plating equipment, arranging the copper target in parallel relative to the magnesium/magnesium alloy substrate, and performing infiltration plating to obtain an infiltration plating layer; the specific diffusion coating parameters are controlled as follows: the source voltage of the copper target is 600-700V, the working voltage of the magnesium/magnesium alloy matrix is 400-450V, the distance between the copper target and the magnesium/magnesium alloy matrix is 8-15 mm, the argon pressure is 20-45 Pa, and the infiltration plating time is 3-5 h. The diffusion coating realizes gradient release of Cu ions by utilizing different Cu ion concentrations of each layer, and performs strong antibacterial treatment aiming at early infection with strong postoperative infection degree by releasing high-concentration Cu ions; cu ions with continuously reduced concentration are released for the delayed infection with continuously weakened infection degree, and weak antibacterial treatment is carried out, so that the release of Cu ions and the antibacterial function are dynamically matched.

Description

Method for preparing antibacterial coating on surface of magnesium and magnesium alloy

Technical Field

The invention belongs to the technical field of metal material surface coatings, and particularly relates to a method for preparing an antibacterial coating on the surfaces of magnesium and magnesium alloy.

Background

Postoperative infection is one of the most serious and complex complications in orthopedic surgery, and causes great threat to wound healing and even life of patients, and is always highly valued by clinicians and related medical staff. Among them, infection caused by invasion of pathogenic bacteria into bone tissue during implantation of the orthopedic implant material is one of the main causes of infection after orthopedics. Infection in orthopedic artificial implantation surgery is classified into early infection and late infection. Early infection mainly is that when the operation incision exposes the operation field, operations such as cutting, pulling, separating, implanting and the like lead to external bacteria to invade the incision, so that the postoperative infection risk is increased, and the infection risk is generally maximum and the infection degree is stronger when the operation is continued for about one month after the operation. The delayed infection is caused by the decrease of the physique of individuals after operation of patients, and generally occurs 2-3 months after operation, and the infection degree is weaker.

At present, in order to avoid the occurrence of orthopedic operation infection clinically, two methods of preoperative prevention and postoperative treatment are mainly adopted. The preoperative method for preventing infection mainly comprises keeping the surrounding environment clean during operation, strictly sterilizing surgical instruments and implants, shortening the operation time, and the like, and the postoperative treatment mainly adopts surgical operations such as antibiotic therapy, debridement, and the like. However, these conventional therapies are inefficient, preoperative prophylaxis does not completely avoid bacterial invasion, and post-operative treatment can cause pain to the patient, bacteria can also develop resistance to antibiotics, so that bacteria are insensitive to antibiotics, and debridement operations cannot completely remove bacteria. Therefore, the ideal method for avoiding infection is to optimally design the implant material to have the capability of resisting bacterial infection, and can dynamically kill bacteria at different stages of the implantation period according to different infection degrees without the need of subsequent postoperative anti-infection treatment.

The magnesium alloy is a novel biodegradable (absorbable) bone implant material with great clinical application prospect due to the characteristics of good biocompatibility, mechanical property matched with bone tissue, capability of being degraded and absorbed in human body and the like. Although the magnesium alloy has good application prospect in the field of orthopedic implantation as a biological material, the magnesium alloy is also easy to cause infection in the degradation process. Therefore, when the degradable magnesium alloy is used as an orthopedic implant material for functional design, the antibacterial function is taken as one of the considerations, the magnesium alloy is expected to have the capability of resisting bacterial infection, can kill common bacteria in orthopaedics, avoid the occurrence of postoperative infection of orthopaedics, and provide a good action environment for the subsequent osteogenesis and vascularization functions of the magnesium alloy implant. Research shows that the high alkaline environment generated by the degradation of magnesium alloy in body fluid can destroy the living condition of bacteria and inhibit the growth and propagation of bacteria, thereby playing a role in killing bacteria. However, in a complex internal environment of the human body, the body fluid buffer effect weakens the alkaline environment generated by the degradation of the magnesium alloy, resulting in weakening or disappearance of the antibacterial effect depending on the alkaline environment alone. Therefore, more research is being conducted to address this problem, and long-lasting antimicrobial properties are provided by more efficient methods.

According to the design thought of the magnesium alloy, an alloy element is expected to be added into magnesium, so that the designed novel magnesium alloy not only has an antibacterial effect through an alkaline environment generated by degradation, but also can release antibacterial metal ions to kill bacteria in the degradation process. Therefore, the sterilization effect of the magnesium alloy can be enhanced, and the antibacterial effect can be continuously exerted by releasing antibacterial metal ions after the alkaline antibacterial effect is weakened or even disappears. Targets were targeted to copper elements by literature review and investigation. Copper has so far been the only solid material that has been registered for U.S. Environmental Protection Agency (EPA) bacteriostasis. Copper can inhibit the growth of pathogenic bacteria for a long time, and copper ions or copper compounds have high-efficiency killing effects on a plurality of bacteria such as staphylococcus aureus, escherichia coli, enterobacter aerogenes, candida albicans, pseudomonas aeruginosa and the like. It can be seen that if the copper element is combined with the magnesium alloy and a certain amount of copper ions are released during the implantation, it is possible to effectively prevent and treat bacterial infection caused by the implant.

Currently, the combination of copper and magnesium is mainly achieved by alloying. Experimental results show that the magnesium-copper alloy can continuously release copper ions to generate an antibacterial effect when being degraded in vivo, overcomes the defect of the antibacterial effect in an alkaline environment, and has remarkable killing effect on staphylococcus aureus, escherichia coli and the like. However, due to the Mg matrix and Mg ₂ The strong galvanic corrosion between the Cu second phases causes the magnesium-copper alloy to degrade at an excessive rate, thus greatly limiting the clinical application thereof. Therefore, the alloying means for realizing the combination of magnesium and copper is not an optimal method, and the requirements of clinically matching the degradation rate and the antibacterial property of the implant are difficult to meet.

The copper-containing antibacterial coating is prepared on the surface of the magnesium alloy, so that the problem of galvanic corrosion between copper and a magnesium matrix can be effectively avoided, the coating can also endow the alloy with excellent antibacterial performance through the release of Cu ions while reducing the degradation rate of the magnesium alloy, and the problem of infection caused in the implantation process of the magnesium alloy is solved. At present, few researches are carried out on preparing a copper-containing antibacterial coating on the surface of a magnesium alloy, and the methods of spin coating, film coating, chemical plating, hydrothermal treatment and the like are mainly inquired, but the copper ion release rate of the coating prepared by the method is single, the gradient release of copper ions cannot be realized according to different infection degrees of early postoperative infection, delayed postoperative infection and other stages, the method is prepared by solution media in the atmospheric environment, the pollution and oxidization of a magnesium matrix and a coating material are easily caused, other unnecessary elements are introduced into the surface of the magnesium matrix, and along with the continuous improvement of green environmental protection requirements, the treatment cost of waste liquid is high.

Therefore, there is a need to develop a magnesium alloy surface copper antibacterial coating which is environment-friendly, pollution-free, simple and easy to implement and can change the release amount of copper ions according to the infection degree at different stages after operation.

Disclosure of Invention

The invention provides a method for preparing an antibacterial coating on the surface of magnesium and magnesium alloy, wherein the coating obtained by the method has stable and controllable components, good binding force with a substrate and realizes the gradient release of copper ions according to different infection degrees at different stages such as early infection and delayed infection after operation.

The technical scheme adopted for solving the technical problems is as follows: the method for preparing the antibacterial coating on the surfaces of the magnesium and the magnesium alloy is characterized by comprising the following preparation steps: mounting a copper target at a target position of double-layer glow plasma infiltration plating equipment, fixing a magnesium/magnesium alloy substrate on a sample table of the double-layer glow plasma infiltration plating equipment, arranging the copper target in parallel relative to the magnesium/magnesium alloy substrate, and performing infiltration plating to obtain an infiltration plating layer; the specific diffusion coating parameters are controlled as follows: the source voltage of the copper target is 600-700V, the working voltage of the magnesium/magnesium alloy matrix is 400-450V, the distance between the copper target and the magnesium/magnesium alloy matrix is 8-15 mm, the argon pressure is 20-45 Pa, and the infiltration plating time is 3-5 h.

The main function of the source voltage is to control the ion bombardment energy and density of the source surface, and further control the supply of the alloy element of the source. The higher the source voltage, the higher the ion bombardment energy and ion bombardment density of the source surface, and the larger the alloy element supply amount. The source voltage also has an optimum range, either too high or too low to be good for metal penetration. As the source voltage Vs increases, the ion bombardment density of the source surface increases (the source current Is increases), and the alloy element supply amount M I increases, resulting in an increase in the workpiece surface alloy concentration C, and an increase in the alloy layer thickness. However, vs must not be too high, otherwise, because the supply of the alloy element is too large, a too thick deposition layer is formed on the surface of the workpiece, so that the bombardment effect of ions on the surface of the workpiece is weakened, the diffusion speed of the alloy element is reduced, and the thickness Ld of the diffusion layer is reduced. And controlling the optimal source voltage of the copper target to 600-700V according to the required deposition layer and diffusion layer, wherein both C and Ld are optimal.

The main effect of the workpiece voltage is to heat the workpiece to reach the metal infiltration temperature through the bombardment effect of ions on the surface of the workpiece. The higher the workpiece voltage, the higher the bombardment energy of the ions on the workpiece surface, and the higher the workpiece surface temperature. The workpiece voltage is either too high or too low, which is detrimental to achieving optimal surface alloying penetration. By researching the influence rule of the workpiece voltage when copper is infiltrated on the surface of the magnesium/magnesium alloy, the optimal workpiece voltage is 400-450V. When the workpiece voltage Vc is lower than 400V, the concentration of copper elements in the surface deposition layer is higher, but the ion bombardment energy and the bombardment density on the surface of the workpiece are small, so that the promotion effect on diffusion is small, and the absorption and diffusion of copper elements are not facilitated; when Vc is higher than 450V, ion bombardment on the surface of the workpiece is enhanced, which is favorable for the absorption and diffusion of copper elements, but the back sputtering is enhanced, so that the surface of the workpiece is difficult to keep high-concentration copper elements, and the thickness Ld of a diffusion layer is also reduced; and because the melting point of the magnesium/magnesium alloy is lower, the too high working voltage can lead to the too high surface temperature of the magnesium/magnesium alloy workpiece, so that the magnesium matrix structure is coarse or the material is softened.

The size of the gap between the workpiece and the source should be selected to take into account the spatial transport of the alloying elements. The large polar distance can cause the collision times of the alloy element to be increased and lost in the space transportation process from the source electrode to the workpiece, so that the utilization rate of the alloy element is low, and the formation of a high-concentration alloy permeation layer is not facilitated; the small inter-electrode distance is beneficial to the formation of the high alloy infiltration layer, but when the inter-electrode distance is too small, the tiny change of the inter-electrode distance can have a great influence on the composition and thickness of the alloy infiltration layer. Experimental results show that the optimal distance between the copper target and the magnesium/magnesium alloy matrix is 8-15 mm when copper is plated on the surface of the magnesium/magnesium alloy.

The argon gas pressure directly influences the supply capacity of copper elements and the absorption capacity of a magnesium/magnesium alloy matrix, thereby influencing the formation of an alloy infiltration layer. The gas pressure is too high or too low to facilitate the formation of an optimal alloy deposit. As the gas pressure P increases, the ion bombardment density of the source surface increases, which Is manifested by an increase in the source current Is. The enhancement of the ion bombardment density of the source surface will inevitably lead to an increase in the source sputtering amount, but the back scattering effect is also enhanced due to the rise of the P value, so that a large amount of copper element is returned to the source surface by collision, and finally the source supply MI is reduced. As MI decreases, the workpiece surface alloy concentration C decreases and the diffusion layer thickness Ld decreases. When the P value is low, the free path of gas collision increases, and the ion bombardment energy increases, so that the supply amount of the alloy element is large. However, because the reverse sputtering on the surface of the workpiece is also stronger, the alloy element can be sputtered away again after reaching the surface of the workpiece, and the formation of high-concentration copper ions is not facilitated; in addition, the promotion of diffusion is impaired due to the low ion density of the bombarded surface, which is also detrimental to the formation of thicker alloy strike layers. Experimental results show that the optimal working air pressure is 30-40 Pa, and both C and Ld are optimal.

The time for the diffusion coating is mainly determined by the desired thickness of the diffusion coating. Theoretically, the thickness of the diffusion layer rises in a parabolic manner with the time of diffusion coating, and the thickness of the deposition layer rises in a straight line with the time of diffusion coating. However, in practice, as the time of the diffusion coating is prolonged, the diffusion and diffusion coating speed is also reduced due to the increase of the thickness of the diffusion coating, and the internal stress generated by thickening of the diffusion coating is also unfavorable for the continued increase of the diffusion coating. In addition, when the infiltration plating time is too long, the effect of reverse sputtering can adversely affect the uniform distribution of the infiltration plating elements in the infiltration plating layer. Therefore, according to experimental study results, the infiltration time is preferably 3-5 hours when copper is plated on the surface of the magnesium/magnesium alloy.

Preferably, the diffusion coating layer comprises a deposition layer positioned on the surface of the magnesium/magnesium alloy matrix and a diffusion layer penetrating from the surface of the magnesium/magnesium alloy matrix into the interior; the thickness of the deposition layer is 10-15 mu m, the components are copper and unavoidable impurities, and the microstructure is alpha phase; the thickness of the diffusion layer is 5-12 mu m, and Cu in the diffusion layer forms Mg ₂ Cu and Mg ₂ The volume fraction of Cu decreases from 2 to 5vol.% to 0 in the surface to interior direction of the magnesium/magnesium alloy matrix. The thickness of the deposition layer and the diffusion layer in this range is optimal, and Mg in the diffusion layer can be realized ₂ The gradient distribution of Cu is beneficial to realizing the gradient release of copper ions aiming at different infection degrees of different stages such as early infection and delayed infection after operation.

Preferably, the magnesium alloy is Mg-Sr alloy, mg-Gd alloy or Mg-Dy alloy, wherein the mass percentage content of Mg is more than 95 wt%.

Preferably, the magnesium alloy is Mg-Gd-Dy-Zr alloy, wherein the mass percent of Mg is more than 95 wt%.

Compared with the prior art, the invention has the advantages that: because the double-glow copper plating on the surface of the magnesium/magnesium alloy is a process of adsorption deposition and diffusion, the invention is formed by controlling the source voltage of a copper target of double-layer glow plasma diffusion plating equipment, the working voltage of a magnesium/magnesium alloy matrix, the relative position of a target material and the matrix, the argon gas pressure and the diffusion plating timeDiffusion coating, wherein copper element of the diffusion coating after deposition is diffused into the surface layer of the magnesium/magnesium alloy matrix to form a diffusion layer, and the copper element in the diffusion layer is combined with the magnesium element to form Mg ₂ Cu and a magnesium/magnesium alloy matrix belong to metallurgical bonding, gradient release of Cu ions is realized by utilizing different concentrations of Cu ions in each layer, and high-concentration Cu ion release is performed for early infection with stronger postoperative infection degree, so that strong antibacterial treatment is performed; cu ions with continuously reduced concentration are released for the delayed infection with continuously weakened infection degree, and weak antibacterial treatment is carried out, so that the release of Cu ions and the antibacterial function are dynamically matched.

After the surface treatment of magnesium and magnesium alloy by adopting the preparation method provided by the invention, the corrosion rate is below 0.2mm/year, the cytotoxicity rating is 0 level, and the method has no cytotoxicity.

Detailed Description

The present invention is described in further detail below with reference to examples.

Example 1

1) A40X 25X 3mm copper (Cu) target was prepared by electromagnetic vacuum melting.

2) Copper (Cu) targets are arranged at the target positions of double-layer glow plasma infiltration plating equipment, and sand paper with different roughness is adopted for the copper (Cu) targetsThe surface of the Mg-Sr (the mass percentage content of Mg is 97 wt%) alloy is polished to 2000#, then horizontally fixed on a sample table of double-layer glow plasma diffusion plating equipment and positioned right below a copper (Cu) target, and the copper target is arranged in parallel relative to the Mg-Sr alloy, so that the relative position of the Mg-Sr alloy and the target is kept unchanged. The copper (Cu) target is connected to a radio frequency power supply, and the source voltage is 700V. The Mg-Sr alloy matrix is connected with a direct current power supply, the working voltage is 420V, and the distance between a copper (Cu) target and the Mg-Sr alloy matrix is 10mm. In the whole preparation process, the argon pressure is 40Pa, the working time is 3 hours, and finally the infiltration layer with a deposition layer and a diffusion layer is obtained.

The components of the deposition layer are copper and unavoidable impurities, and the microstructure is alpha phase; cu in diffusion layer forms Mg ₂ Cu and Mg ₂ Volume fraction of Cu along Mg-Sr matrix tableThe face-to-interior direction is continually reduced from 3vol.% to 0.

Example 2:

1) A copper (Cu) target of 40X 3mm was prepared by using spherical copper powder with a diameter of 13-53 μm using a laser selective melting 3D printing technique.

2) Mounting 40×40×3mm copper (Cu) target material in double-layer glow plasma infiltration plating equipment, and adopting sand paper with different roughness to implement the methodThe surface of the Mg-Gd-Dy-Zr alloy is polished to 2000# and then horizontally fixed on a sample table of double-layer glow plasma diffusion plating equipment, and the surface is positioned right below a copper (Cu) target, the copper target is arranged in parallel relative to the Mg-Gd-Dy-Zr alloy, and the relative position of the Mg-Gd-Dy-Zr alloy and the target is kept unchanged. The copper (Cu) target is connected to a radio frequency power supply, and the source voltage is 680V. The Mg-Gd-Dy-Zr alloy matrix is connected with a direct current power supply, the working voltage is 450V, and the distance between a copper (Cu) target and the matrix is 8mm. In the whole preparation process, the argon pressure is 40Pa, the working time is 5 hours, and finally the infiltration layer with a deposition layer and a diffusion layer is obtained.

The components of the deposition layer are copper and unavoidable impurities, and the microstructure is alpha phase; cu in diffusion layer forms Mg ₂ Cu and Mg ₂ The volume fraction of Cu decreases from 3.5vol.% to 0 in the direction from the surface to the interior of the Mg-Gd-Dy-Zr matrix.

Example 3

1) A copper (Cu) target of 20X 60X 3mm was prepared by electromagnetic vacuum melting.

2) Copper (Cu) targets are arranged at the target positions of the arc glow plasma infiltration plating equipment, and sand paper with different roughness is adopted to carry out the processThe surface of the Mg (99.994 wt.%) block is polished to 2000#, then horizontally fixed on a sample table of a double-layer glow plasma diffusion plating device and positioned right below a copper (Cu) target, and the copper target is arranged in parallel relative to the Mg block, so that the relative position of the Mg block and the target is kept unchanged. Copper (Cu) target is connected to radio frequency power supplyThe source voltage is 600V. The Mg block is connected with a direct current power supply, the working voltage is 400V, and the distance between a copper (Cu) target and the Mg block is 8mm. In the whole preparation process, the argon pressure is 30Pa, the working time is 4 hours, the treatment temperature is 480 ℃, and finally the infiltration layer with a deposition layer and a diffusion layer is obtained.

The components of the deposition layer are copper and unavoidable impurities, and the microstructure is alpha phase; cu in diffusion layer forms Mg ₂ Cu and Mg ₂ The volume fraction of Cu decreases from 4vol.% to 0 in the direction from the magnesium base surface to the inside.

Comparative example:

1) Surface treatment: sandpaper with different roughnessThe surface of the sample was polished to 2000#, polished with 3.5 μm diamond gypsum, then degreased with absolute ethanol in an ultrasonic bath for 15 minutes, and then dried at room temperature for later use;

2) Preparing copper-containing composite sol: 7.5wt% PCL with the molecular weight of 70000-90000g/mol is dissolved in chloroform, and bioactive glass (2 wt% Cu-BGN) containing 2wt% nanometer copper powder is mixed with the solution to prepare copper-containing composite sol;

3) Spin coating of magnesium samples: a sample tray of 25X 25mm is selected, a magnesium sample is placed on a sample stage of a spin coater, 300 microliter of sol is dripped in the center of the magnesium sample by using a microsyringe, the sol is pre-rotated for 10s at a speed of 500 revolutions per minute, after the sol spreads on the surface of the sample, the sol is rotated for 30s at a speed of 3000 revolutions per minute, and the spin-coated sample is placed in a vacuum drying box and dried in vacuum at normal temperature for 24h.

The resulting 3 examples were tested for deposited and diffused layer thickness and the specific results are shown in table 1.

The resulting 3 and 1 comparative examples were subjected to corrosion performance test, cytotoxicity rating, cytotoxicity evaluation, and specific results are shown in table 1.

The detection method of the deposition layer and the diffusion layer comprises the following steps: and (3) polishing the section of the sample prepared by the surface coating to 2000#, polishing, placing under a scanning electron microscope, and adopting secondary electron observation and measurement to obtain the product.

Corrosion performance test: and (3) washing and drying the tablet sample with the diameter of phi 10mm multiplied by 3mm after the surface coating preparation by alcohol. 3 in parallel. Before the start of the experiment, all sample weights were measured and recorded using an electronic microbalance, then the samples were placed in clean 15mL centrifuge tubes, fresh Hank's solution was added to each centrifuge tube in a ratio of sample surface area (cm 2) to Hank's solution volume (mL) of 1.25cm2/mL (solution formulation as in table 2, pH adjusted to 7.4 after formulation), and then placed in an incubator at 37±0.5 ℃ with the soak solution changed once per day. After soaking for 30 days, the soaked sample was taken out and the surface was dried with a blower, a macroscopic photograph of the corroded sample was taken, then each was ultrasonically cleaned sequentially with chromic acid solution (200 g/L), distilled water, and alcohol for 10 minutes, and the blower was dried and weighed to calculate the average corrosion rate. The average corrosion rate was calculated as:

Corrosion rate＝(K×W)/(A×T×D)

wherein: k=8.76×104; w is the difference in sample weight (g) before and after soaking; a is the surface area (cm 2) of the sample exposed to Hank's solution during soaking; t is the sample soaking time (h); d is the material density (g/cm 3).

Cytotoxicity ranking method: 1) Preparing a material leaching solution: cytotoxicity ratings in the present invention were tested using the leaching solution method. Test samples were immersed in 15mL centrifuge tubes containing serum-free alpha-MEM medium (Hyclone, USA) and endothelial cell medium Sciencell, USA, respectively, at a ratio of 1.25cm2/mL sample surface area to volume, and incubated in a sterile incubator at 37.+ -. 0.5 ℃ for 24h according to ISO10993-5 standard. After the soaking, carefully taking out the sample in the tube by using forceps, discarding the sample, centrifuging the rest soaking liquid in a centrifuge at 5000r/min for 5min, taking supernatant, filtering by using a 0.22 mu m pillow filter, and placing the filtered leaching liquid in a sterile tube for standby at 4 ℃. 2) Cytotoxicity test: the preosteoblasts MC3T3-E1 of the rats in logarithmic growth phase after passaging were carefully washed three times with sterile PBS solution, and after 2min of digestion with 0.25% trypsin, the cells were collected and centrifuged, and counted by a counting plate. At 5X 10 ³ cell density of cells/100mL was inoculated in sterile 96In the well plate, 100 μl of each well, 6 wells were multiplexed. To ensure that the results were accurate and the humidity of the surrounding environment was sufficient, the cells were not seeded in the very edge of the 96-well plate, but sterile PBS solution (solution formulation shown in Table 3) was added. Put in 5% CO ₂ Culturing in a cell incubator at 37+ -0.5deg.C for 24h for cell attachment. At this time, the absorbance of each well of the 96-well plate is tested by an enzyme-labeled instrument, and whether the values are close or not is observed so as to ensure that the cell number of each well is not different and is in the same standard before the material leaching liquid is added. After careful pipetting of the cell culture broth from each well, PBS was used for washing, and 100. Mu.L of material extract and 10% fetal bovine serum were added to each well and incubated with cells for 1 day. After the time point, the material extract in the wells was discarded, 5mg/mL MTT was added, 100. Mu.L per well, incubation was continued in the cell incubator for 4 hours, then 150. Mu.L of dimethyl sulfoxide (DMSO) was added per well with careful pipetting, and the mixture was left on a shaker at room temperature with gentle shaking for 15min to allow complete dissolution. The absorbance (OD) of each well was measured with an enzyme-labeled instrument and the value was recorded, the measurement wavelength was 490nm, and the reference wavelength was 570nm. The effect of the magnesium-strontium alloy on the cell proliferation rate was evaluated by the change of the OD value after 1 day of culture. And calculating the relative proliferation rate of the cells according to the OD value result: relative Cell Growth Rate% (RCGR) =od experimental group/OD negative control x 100%, where the negative control was PBS solution wells. The experiment was repeated three times.

According to RGR value, evaluating cytotoxicity by referring to ISO10993-5 in vitro cytotoxicity test, wherein the evaluation standard is (1) RGR value is not less than 100%, cytotoxicity grade is 0 grade, and the product is qualified; (2) RGR value is more than or equal to 80%, cytotoxicity grade is grade 1, and the product is qualified; (2) RGR value is 50% -80%, cytotoxicity grade is grade 2, should combine the comprehensive evaluation of cell morphology; RGR value is less than or equal to 49%, cytotoxicity grade is 3-4, and the product is unqualified. TABLE 1 parameter control and Performance test results for the diffusion coatings of examples and comparative examples of the present invention

TABLE 2 Hank's solution composition for corrosion performance testing in the present invention

Composition of the components	Concentration, g/L
		NaCl	8.00
KCl	0.40
		CaCl ₂	0.14
NaHCO ₃	0.35
		Na ₂ HPO ₄	0.12
MgSO ₄	0.20
		KH ₂ PO ₄	0.06
Glucose	1.00

TABLE 3 PBS solution Components used in cytotoxicity experiments in the present invention

Composition of the components	Concentration, g/L
		NaCl	8.00
KCl	0.20
		Na ₂ HPO ₄	2.89
KH ₂ PO ₄	0.20

Claims

1. The method for preparing the antibacterial coating on the surfaces of the magnesium and the magnesium alloy is characterized by comprising the following preparation steps: mounting a copper target at a target position of double-layer glow plasma infiltration plating equipment, fixing a magnesium/magnesium alloy substrate on a sample table of the double-layer glow plasma infiltration plating equipment, arranging the copper target in parallel relative to the magnesium/magnesium alloy substrate, and performing infiltration plating to obtain an infiltration plating layer; the specific diffusion coating parameters are controlled as follows: the source voltage of the copper target is 600-700V, the working voltage of the magnesium/magnesium alloy matrix is 400-450V, the distance between the copper target and the magnesium/magnesium alloy matrix is 8-15 mm, the argon pressure is 20-45 Pa, and the infiltration plating time is 3-5 h; the diffusion coating comprises a deposition layer positioned on the surface of the magnesium/magnesium alloy matrix and a diffusion layer penetrating into the magnesium/magnesium alloy matrix from the surface of the magnesium/magnesium alloy matrix; the thickness of the deposition layer is 10-15 mu m, the components are copper and unavoidable impurities, and the microstructure is alpha phase; the thickness of the diffusion layer is 5-12 mu m, and Cu in the diffusion layer forms Mg ₂ Cu and Mg ₂ The volume fraction of Cu is from the surface to the inside of the magnesium/magnesium alloy matrix2 to 5vol.% is continuously reduced to 0.

2. The method for preparing the antibacterial coating on the surface of the magnesium and magnesium alloy according to claim 1, wherein the method comprises the following steps: the magnesium alloy is Mg-Sr alloy, mg-Gd alloy or Mg-Dy alloy, wherein the mass percentage content of Mg is more than 95 percent.

3. The method for preparing the antibacterial coating on the surface of the magnesium and magnesium alloy according to claim 1, wherein the method comprises the following steps: the magnesium alloy is Mg-Gd-Dy-Zr alloy, wherein the mass percentage content of Mg is more than 95 wt%.