Metallic alloy surface magnetic antimicrobial microstructure and method of making same

Abstract

The application discloses a metal alloy surface magnetic antibacterial microstructure and a manufacturing method thereof. The magnetic antibacterial microstructure is antibacterial copper-coated magnetic nano-Fe2O3 loaded on a metal alloy surface, and the copper-coated magnetic nano-Fe2O3 is formed through in-situ reaction of copper oxide coated iron powder at high temperature. The manufacturing method comprises the following steps: firstly, depositing copper oxide on the surface of acidified iron powder through a plasma spraying process, and then uniformly mixing the copper oxide with metal alloy powder through a high-energy ball milling process; secondly, sintering the mixed powder into a shape through a powder sintering process, and scanning the surface of the copper-coated Fe2O3 dispersed metal alloy by means of an ultrafast laser to obtain the magnetic antibacterial microstructure. The manufacturing method can not only obtain the microstructure reinforced by the antibacterial copper, but also effectively avoid the weakening of the magnetism of Fe2O3 by the high-energy laser beam by means of the high reflection of copper on the laser, thereby realizing the manufacturing of the magnetic antibacterial microstructure and significantly improving the directional induction regulation and control capability of bone tissue.

Description

Technical Field

[0001] This invention relates to a magnetic antibacterial microstructure and its manufacturing method, specifically to a magnetic antibacterial microstructure on a metal alloy surface and its manufacturing method. Background Technology

[0002] Near-equal atomic ratio NiTi alloy is a titanium-based intermetallic compound. Compared to medical-grade 316L stainless steel and TC4, its stress-strain curve exhibits a significant nonlinear relationship and is similar to that of natural bone. Its elastic modulus is also close to that of human bone. After implantation, it can significantly reduce stress shielding effects, prevent bone resorption, and also possesses superior fatigue performance, making it more adaptable to the complex and changing human body environment. With temperature changes, NiTi alloy undergoes a macroscopic shape transformation between the austenitic parent phase and twinned martensite phases, achieving a shape memory effect. When in the austenitic state, it generates large strains far exceeding its elastic limit strain, but after unloading the external force, the strain returns to normal, thus NiTi alloy often exhibits hyperelastic characteristics. Furthermore, NiTi alloy is non-cytotoxic and has good cell compatibility with osteoblasts and fibroblasts, and has been applied in the field of biomaterials. However, NiTi alloy is a bioinert material, lacking bioactivity and antibacterial properties after implantation, which cannot meet the multifunctional requirements of current implantable devices.

[0003] In recent years, surface modification methods have become an important approach to solving the aforementioned problems. For example, porous TiO2 / HA / TiO2 composite coatings prepared by sol-gel processes endow them with bioactivity and osteoinductive properties; anodic oxidation is used to construct Cu-loaded Ni-Ti-O nanopores on the surface of NiTi alloys to enhance their antibacterial function. These surface modification methods have improved the biological function of NiTi alloys to some extent. However, due to the differences in physical properties between the coating and the NiTi alloy substrate, and the large interfacial stress between the coating and the alloy substrate under load after implantation in the human body, the interfacial bonding strength is low, which easily leads to the premature failure of the bio-coating and consequently the loss of its biological function. Summary of the Invention

[0004] Objective of the invention: The present invention aims to provide a magnetic antibacterial microstructure on the surface of a metal alloy with antibacterial and biological functions; another objective of the present invention is to provide a method for manufacturing the magnetic antibacterial microstructure on the surface of the metal alloy.

[0005] Technical solution: The magnetic antibacterial microstructure on the surface of the metal alloy described in this invention is a copper-coated magnetic nano-iron oxide loaded on the surface of the metal alloy, and the copper-coated magnetic nano-iron oxide is formed by iron powder coated with copper oxide through a high-temperature in-situ reaction.

[0006] Preferably, the mass ratio of copper to magnetic nano-ferric oxide is 1:1 to 1.2:1, and the mass percentage of copper-coated magnetic nano-ferric oxide in the microstructure is 5 wt.% to 10 wt%.

[0007] This invention addresses the need for bio-functionalized metal alloys by designing a copper oxide-coated iron / NiTi alloy composite material system. Based on the in-situ reaction between copper oxide and iron, copper-coated ferric oxide is formed. Simultaneously, by utilizing the reflection effect of copper on high-energy laser beams, the weakening of the magnetism of ferric oxide during ultrafast laser scanning is effectively avoided. This results in a microstructure of antibacterial copper-coated magnetic nano-ferric oxide loaded on the surface of the metal alloy. The invention includes the following steps:

[0008] (1) Put the iron powder into hydrochloric acid solution for surface acidification and cleaning, rinse and dry;

[0009] (2) A copper oxide coating is deposited on the surface of the iron powder obtained in step (1) using a plasma spraying process to obtain copper oxide coated iron powder.

[0010] (3) Using a high-energy ball milling process, metal alloy powder and copper oxide-coated iron powder are ball milled and mixed to obtain copper oxide-coated iron powder / metal alloy composite powder.

[0011] (4) Copper oxide-coated iron powder / metal alloy composite powder is sintered at high temperature under the protection of argon / carbon monoxide mixed gas to induce in-situ reaction between iron and copper oxide, thereby generating copper-coated ferric oxide / metal alloy composite material.

[0012] (5) Using an ultrafast laser, the surface of copper-coated ferric oxide / metal alloy composite material is scanned to form a microstructure of copper-coated magnetic nano-ferric oxide loaded with antibacterial properties.

[0013] Preferably, in step (1), the particle size of the iron powder is 1-5 μm, and the volume fraction of the hydrochloric acid solution is 5-10%; in step (2), the thickness of the copper oxide coating deposited on the surface of the iron powder is 1-10 μm; in step (3), the mass ratio of the copper oxide-coated iron powder to the metal alloy powder is 5 wt.%-10 wt%; in step (4), the high-temperature sintering temperature is 1000-1250℃; and in step (5), the power of the ultrafast laser is 0.4-1 W.

[0014] Preferably, the metal alloy is a nickel-titanium alloy.

[0015] Invention Principle: Based on the need for biofunctionality of medical metal alloys, and leveraging the repair effect of magnetic Fe2O3 nanoparticles on bone defects under external magnetic field excitation and the excellent antibacterial function of copper, a copper oxide-coated iron / NiTi alloy composite material system based on plasma spraying was designed and prepared. Through high-temperature induced in-situ reaction between copper oxide and iron during powder sintering in an inert argon / carbon monoxide mixed gas environment, copper-coated ferric oxide is generated and dispersed in the metal alloy matrix. Secondly, an ultrafast laser is used to scan and form a microporous structure on the surface of the copper-coated ferric oxide / metal alloy. Based on the reflection of the ultrafast laser beam by copper, the weakening effect of the ultrafast laser beam on the magnetism of ferric oxide is avoided, effectively maintaining the magnetic function of ferric oxide. Furthermore, the disturbed molten pool formed by the thermal effect of the ultrafast laser beam facilitates the in-situ doping and dispersion of copper atoms and magnetic ferric oxide into the microstructure, thereby realizing the fabrication of magnetic antibacterial microstructures on the surface of the metal alloy.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0017] (1) In view of the bioinertness of NiTi alloy, based on the excellent bone defect repair effect of magnetic Fe2O3 nanoparticles and the excellent antibacterial function of inexpensive copper element, a copper oxide coated iron / NiTi alloy composite material system based on plasma spraying was innovatively designed. In the inert argon / carbon monoxide mixed gas environment, the high temperature of powder sintering can induce the in-situ reaction between copper oxide and iron. At the same time, a small amount of carbon monoxide gas can reduce the residual copper oxide, thereby obtaining copper coated ferric oxide / nickel-titanium alloy composite material, endowing NiTi alloy with bio-function;

[0018] (2) Based on the bone tissue induction characteristics of the surface microstructure of titanium alloy, a microstructure doped with magnetic Fe2O3 nanoparticles and antibacterial copper atoms was innovatively designed. The magnetic Fe2O3 nanoparticles can greatly stimulate the growth of bone tissue under the intervention of an external magnetic field, effectively improving the bone induction ability of the surface microstructure of titanium alloy; at the same time, the doping of copper atoms also endows the microstructure with excellent antibacterial function.

[0019] (3) The copper-coated magnetic iron oxide microstructure fully utilizes the antibacterial copper's reflective effect on lasers, which can effectively reduce the weakening of magnetism by high-energy laser beams during the laser processing of magnetic materials. This design method significantly expands the application field of laser forming technology for magnetic composite materials. Attached Figure Description

[0020] Figure 1 This is a microscopic morphology image of the magnetic antibacterial microstructure on the surface of the nickel-titanium alloy manufactured in Example 1;

[0021] Figure 2Comparative diagram of bone morphogenetic protein gene expression after 14 days of culture of the magnetic antibacterial microstructures on the surface of nickel-titanium alloys manufactured in Examples 2, 3 and Comparative Example 1.

[0022] Figure 3 This is a comparison of the number of cells cultured for different times on the magnetic antibacterial microstructures on the nickel-titanium alloy surface manufactured in Examples 2, 3 and Comparative Example 1. Detailed Implementation

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0024] Example 1

[0025] (1) After surface acidification and cleaning of iron powder with a particle size of 1 μm in a 5% hydrochloric acid solution, it is rinsed with deionized water and then dried with nitrogen.

[0026] (2) A copper oxide coating with a thickness of 1 μm is deposited on the surface of the iron powder described in step (1) using a plasma spraying process to obtain copper oxide coated iron powder.

[0027] (3) Using a high-energy ball milling process, the copper oxide-coated iron powder obtained in step (2) and the nickel-titanium alloy powder are ball milled and mixed at a mass ratio of 5wt% to obtain copper oxide-coated iron powder / nickel-titanium alloy composite powder.

[0028] (4) The copper oxide-coated iron powder / nickel-titanium alloy composite powder obtained in step (3) is sintered at 1000℃ under the protection of argon / carbon monoxide mixed gas to induce the in-situ reaction between iron and copper oxide, thereby generating copper-coated ferric oxide / nickel-titanium alloy composite material.

[0029] (5) Using an ultrafast laser with a power of 0.4W, the surface of the copper-coated ferric oxide / nickel-titanium alloy composite material obtained in step (4) is scanned to form a microstructure of copper-coated magnetic nano-ferric oxide loaded with antibacterial properties on the surface.

[0030] Figure 1 The image shows the microstructure of the magnetic antibacterial microstructure on the surface of the nickel-titanium alloy manufactured in Example 1. It can be seen that the alloy surface is covered with shallow pit microstructures with a size of about 1 μm and high surface energy. At the same time, white near-spherical copper-coated magnetic ferric oxide particles are uniformly dispersed near the microstructures, which have a significant promoting effect on the induced growth of bone tissue and antibacterial activity.

[0031] Example 2

[0032] (1) After surface acidification and cleaning of iron powder with a particle size of 5 μm in a 5% hydrochloric acid solution, it is rinsed with deionized water and then dried with nitrogen.

[0033] (2) A copper oxide coating with a thickness of 5 μm is deposited on the surface of the iron powder described in step (1) using a plasma spraying process to obtain copper oxide coated iron powder.

[0034] (3) Using a high-energy ball milling process, the copper oxide-coated iron powder obtained in step (2) and the nickel-titanium alloy powder are ball milled and mixed at a mass ratio of 8wt% to obtain copper oxide-coated iron powder / nickel-titanium alloy composite powder.

[0035] (4) The copper oxide-coated iron powder / nickel-titanium alloy composite powder obtained in step (3) is sintered at 1250°C under the protection of argon / carbon monoxide mixed gas to induce the in-situ reaction between iron and copper oxide, thereby generating copper-coated ferric oxide / nickel-titanium alloy composite material.

[0036] (5) Using an ultrafast laser with a power of 0.8W, the surface of the copper-coated ferric oxide / nickel-titanium alloy composite material obtained in step (4) is scanned to form a microstructure of copper-coated magnetic nano-ferric oxide loaded with antibacterial properties on the surface.

[0037] Example 3

[0038] (1) Iron powder with a particle size of 5 μm was placed in a 10% hydrochloric acid solution for surface acidification and cleaning, rinsed with deionized water, and then dried with nitrogen.

[0039] (2) A copper oxide coating with a thickness of 10 μm is deposited on the surface of the iron powder described in step (1) using a plasma spraying process to obtain copper oxide coated iron powder.

[0040] (3) Using a high-energy ball milling process, the copper oxide-coated iron powder obtained in step (2) and the nickel-titanium alloy powder are ball milled and mixed at a mass ratio of 10wt% to obtain copper oxide-coated iron powder / nickel-titanium alloy composite powder.

[0041] (4) The copper oxide-coated iron powder / nickel-titanium alloy composite powder obtained in step (3) is sintered at 1250°C under the protection of argon / carbon monoxide mixed gas to induce the in-situ reaction between iron and copper oxide, thereby generating copper-coated ferric oxide / nickel-titanium alloy composite material.

[0042] (5) Using a 1W ultrafast laser, the surface of the copper-coated ferric oxide / nickel-titanium alloy composite material obtained in step (4) is scanned to form a microstructure of copper-coated magnetic nano-ferric oxide loaded with antibacterial properties on the surface.

[0043] The nickel-titanium alloy surface magnetic antibacterial microstructures manufactured in Examples 2 and 3 showed an inhibition rate of 99.99% against Staphylococcus aureus after 48 hours of testing. Furthermore, Examples 2 and 3 exhibited higher gene expression, enhancing the ability to induce undifferentiated mesenchymal stem cells to differentiate and proliferate into chondrocytes and osteoblasts, thereby accelerating bone defect repair. This was superior to the gene expression values ​​of single microstructures produced by ultrafast laser ablation. Figure 2 ).

[0044] Comparative Example

[0045] Microstructures were formed on the surface of a NiTi alloy using only a 0.4W ultrafast laser. Cell growth was compared using the NiTi alloy surface microstructures obtained in Comparative Example 1. Figure 3 As the number of cultivation days increased, the magnetic antibacterial microstructures on the nickel-titanium alloy surface in Examples 2 and 3 showed higher absorbance values, reflecting a larger number of live cells. In contrast, the absorbance value of the microstructures on the nickel-titanium alloy surface in Comparative Example 1 remained almost unchanged. This further demonstrates that the magnetic antibacterial microstructures prepared in this invention have excellent cell growth-promoting functions, thereby enhancing biological activity.

Claims

1. A method for manufacturing magnetic antibacterial microstructures on the surface of a metal alloy, characterized in that, The microstructure consists of antibacterial copper-coated magnetic ferric oxide nanoparticles loaded on the surface of a metal alloy. The copper-coated magnetic ferric oxide nanoparticles are formed by a high-temperature in-situ reaction of iron powder coated with copper oxide. The metal alloy is a nickel-titanium alloy, and the manufacturing method includes the following steps: (1) Put the iron powder into hydrochloric acid solution for surface acidification and cleaning, rinse and dry; (2) A copper oxide coating is deposited on the surface of the iron powder obtained in step (1) using a plasma spraying process to obtain copper oxide coated iron powder; (3) Using a high-energy ball milling process, nickel-titanium alloy powder and copper oxide-coated iron powder are ball milled and mixed to obtain copper oxide-coated iron powder / nickel-titanium alloy composite powder. (4) Copper oxide-coated iron powder / nickel-titanium alloy composite powder is sintered at 1000-1250℃ under the protection of argon / carbon monoxide mixed gas to induce in-situ reaction between iron and copper oxide, thereby generating copper-coated ferric oxide / nickel-titanium alloy composite material. (5) Using an ultrafast laser with a power of 0.4 to 1W, the surface of copper-coated ferric oxide / nickel-titanium alloy composite material is scanned to form a microstructure of copper-coated magnetic nano-ferric oxide loaded on the nickel-titanium alloy surface.

2. The method for manufacturing magnetic antibacterial microstructures on the surface of a metal alloy according to claim 1, characterized in that, The mass ratio of copper to magnetic nano-ferric oxide is 1:1 to 1.2:

1.

3. The method for manufacturing magnetic antibacterial microstructures on the surface of a metal alloy according to claim 1, characterized in that, The thickness of the copper oxide coating deposited on the iron powder surface in step (2) of the manufacturing method is 1 to 10 μm.

4. The method for manufacturing magnetic antibacterial microstructures on the surface of a metal alloy according to claim 1, characterized in that, The particle size of the iron powder in step (1) of the manufacturing method is 1-5 μm.

5. The method for manufacturing magnetic antibacterial microstructures on the surface of a metal alloy according to claim 1, characterized in that, The volume fraction of the hydrochloric acid solution in step (1) of the manufacturing method is 5-10%.

6. A magnetic antibacterial microstructure on the surface of a metal alloy manufactured by the method described in claim 1.

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