Method for coating Ca-Cur submicron modified material-doped PLA layer on surface of Ag-DCPD film layer

Abstract

The invention discloses a method for coating a Ca-Cur submicron modified material-doped PLA layer on the surface of an Ag-DCPD film layer, and relates to the technical field of biological coatings on the surfaces of medical materials. The method comprises the following steps: manufacturing an LPBF-NiTi alloy matrix by adopting a laser powder bed melting additive manufacturing technology, and carrying out pretreatment on the LPBF-NiTi alloy matrix; the pretreated LPBF-NiTi alloy matrix is subjected to electrochemical deposition in an electrolyte solution, and the LPBF-NiTi alloy matrix with the deposited Ag-DCPD film layer is obtained; the preparation method comprises the following steps: dissolving CaCl2 and curcumin in absolute ethyl alcohol, putting the solution into a closed container filled with (NH4) 2CO3, and carrying out constant-temperature reaction to obtain a Ca-Cur submicron modified material; polylactic acid is dissolved in dichloromethane, then the Ca-Cur submicron modified material is dispersed in the dichloromethane, and a leaching solution is obtained; and the LPBF-NiTi alloy matrix on which the Ag-DCPD film layer is deposited is subjected to repeated dipping and pulling in the leaching solution, and the LPBF-NiTi alloy matrix coated with the Ag-DCPD / PLA / Ca-Cur composite film layer is obtained. According to the invention, the corrosion resistance, the biocompatibility and the antibacterial and anti-inflammatory performance of the Ag-DCPD film layer are successfully improved.

Description

Technical Field

[0001] This invention relates to the field of bio-coating technology for medical material surfaces, and more particularly to a method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an LPBF-NiTi alloy with a deposited Ag-DCPD film. Background Technology

[0002] As the population ages, the demand for personalized medicine is becoming increasingly prominent, with a growing emphasis on customized implants. In recent years, Laser Powder Bed Fusion (LPBF) technology, capable of directly forming complex, high-precision, dense metal parts, has become a crucial technique for manufacturing high-performance medical implants. Among numerous biomaterials, nickel-titanium (NiTi) alloys, with their unique shape memory effect, elastic modulus similar to human bone, and non-magnetic properties, demonstrate broad application prospects. However, they exhibit Ni content in physiological environments. 2+ Issues such as insufficient release, bioinertness, and antibacterial properties can all lead to implantation failure. Surface modification techniques have proven to be an effective strategy for improving the functionality of metal surfaces. Ag-DCPD can be converted into hydroxyapatite (HAP) in vivo, promoting biomineralization and cell compatibility, and providing sustained Ag release. + Achieving long-term, highly effective antibacterial properties. However, the Ag-DCPD film exhibits a porous, scaly structure, which provides channels for corrosive media to penetrate into the substrate, thereby accelerating film degradation and substrate corrosion. Furthermore, the large amount of Ag released during the initial corrosion stage... + It can cause cytotoxicity and hinder wound healing.

[0003] PLA, as a biodegradable polymer material, not only effectively prevents corrosive media from penetrating into the metal substrate but also has a certain slow-release effect. Therefore, coating the Ag-DCPD film surface with a PLA layer can not only improve the corrosion resistance of the film but also reduce Ag release during the film degradation process. + Release to reduce cytotoxicity. However, due to its material structure and film-forming process, PLA cannot form an absolutely dense layer. Micro- and nanomaterials can fill the "defects" in organic films, extending the permeation paths of oxygen and water, thereby reducing the penetration of corrosive media in the environment and improving the protective effect of the film. Curcumin (Cur) is a natural polyphenol extracted from ginger plants, possessing excellent antibacterial and anti-inflammatory properties. Doping Cur into PLA layers can not only fill the defects in the PLA layer and enhance the corrosion resistance of the film, but also compensate for Ag... +The reduced release leads to a decrease in antibacterial ability. However, the hydrophobicity of Cur severely limits its antibacterial and anti-inflammatory effects. To address this issue, calcium-based submicron materials with high loading capacity, good pH response, ideal biocompatibility, and biodegradability are introduced as its carriers. Moreover, calcium-based submicron materials can serve as nucleation sites to induce the deposition of phosphate mineralization products, further improving the corrosion resistance of the film.

[0004] Ag has not yet been used. + Reports have been published on the synergistic enhancement of antibacterial properties with Cur, and the combination of PLA layers and Ca-Cur submicron modified materials to comprehensively improve the corrosion resistance, osteogenic properties, and antibacterial and anti-inflammatory properties of Ag-DCPD membranes. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of a nickel-titanium alloy Ag-DCPD film. First, a calcium-based submicron material is used as a carrier for Cur to improve its hydrophilicity, and a Ca-Cur submicron material is synthesized. Second, a PLA layer doped with Ca-Cur submicron material is coated onto the surface of an LPBF-NiTi alloy with an already deposited Ag-DCPD film. The prepared composite film aims to synergistically enhance the corrosion resistance and overall bone-promoting properties of the Ag-DCPD film, and can also improve the Ag-Cur film's ability to resist corrosion. + The synergistic effect with Cur further enhances the inhibitory effect on bacterial growth.

[0006] According to one aspect of the present invention, a method is provided for coating an Ag-DCPD film surface with a PLA layer doped with Ca-Cur submicron modified material, wherein Ag-DCPD refers to silver-doped dicalcium phosphate dihydrate, Ca-Cur refers to calcium-based curcumin, and PLA refers to polylactic acid, comprising: S1, substrate manufacturing: manufacturing a nickel-titanium alloy using laser powder bed fusion additive manufacturing technology to obtain an LPBF-NiTi alloy substrate; S2, LPBF-NiTi alloy substrate pretreatment: polishing the obtained LPBF-NiTi alloy substrate, followed by ultrasonic treatment in anhydrous ethanol and deionized water, and then drying; S3, preparing an Ag-DCPD film layer on the surface of the LPBF-NiTi alloy substrate: performing electrochemical deposition using a dual-electrode mode of an electrochemical workstation, using the pretreated LPBF-NiTi alloy substrate as the cathode and a platinum sheet as the anode, and depositing the Ag-DCPD film layer in an electrolyte solution at a preset temperature and a preset current density, wherein the electrolyte solution includes Ag + Ca 2+ PO4 3-After deposition, the substrate was rinsed with deionized water and dried at room temperature to obtain the LPBF-NiTi alloy substrate with deposited Ag-DCPD film; S4, preparation of Ca-Cur submicron modified material: CaCl2 and curcumin were dissolved in anhydrous ethanol in sequence, and then placed in a sealed container containing (NH4)2CO3 and reacted in a constant temperature water bath. After the reaction was completed, the anhydrous ethanol turbid liquid was removed and centrifuged. After centrifugation, the precipitate was washed with distilled water. Centrifugation was performed after each washing. The obtained solid was dried under vacuum to obtain S5, Preparation of the extraction solution: Polylactic acid particles are dissolved in dichloromethane, and then the Ca-Cur submicron modified material is dispersed in it to obtain the extraction solution; S6, Preparation of the composite film: The LPBF-NiTi alloy substrate with deposited Ag-DCPD film is repeatedly immersed and pulled in the extraction solution and dried at room temperature to form Ag-DCPD / PLA / Ca-Cur composite film, completing the coating of the PLA layer doped with Ca-Cur submicron modified material on the surface of the Ag-DCPD film.

[0007] Optionally, in S2, the obtained LPBF-NiTi alloy substrate is polished with 80~800# sandpaper to remove surface oil and uneven oxide film.

[0008] Optionally, in S3, the distance between the anode and cathode is 1~3 cm, the preset deposition temperature is 10~60℃, and the preset current density is 0.1~5 mA / cm². 2 The deposition time is 10~90 min.

[0009] Optionally, the electrolyte solution in S3 consists of an aqueous solution of 0.05~0.15 mol / L Ca(NO3)2·4H2O, 0.001~0.012 mol / L AgNO3, 0.03~0.09 mol / L NH4H2PO4, and 0.3 vol% H2O2.

[0010] Optionally, when preparing the electrolyte solution in S3, NH4H2PO4 can only be added after AgNO3 and Ca(NO3)2·4H2O have been completely dissolved in deionized water.

[0011] Optionally, the concentration of CaCl2 in S4 after dissolving in anhydrous ethanol is 0.1~0.2 mol / L, and the concentration of curcumin is 1~2 mg / mL. Curcumin is added after CaCl2 is completely dissolved in anhydrous ethanol. The weight of (NH4)2CO3 in the sealed container is 10 times that of curcumin.

[0012] Optionally, the temperature of the constant temperature water bath in S4 is 55~65 ℃, the reaction time is 4~8 h; the centrifugation speed is above 4000 rpm, and the centrifugation time is 10 min each time; the vacuum drying temperature is 40~60 ℃, and the drying time is above 24 h.

[0013] Optionally, the concentration of polylactic acid in the solution obtained after dissolving polylactic acid particles in dichloromethane in S5 is 5 wt%~20 wt%, and the concentration of Ca-Cur submicron modified material dispersed therein is 1~10 mg / mL. The dispersion method is magnetic stirring at 300~500 rpm for 20 min, followed by ultrasonic treatment for 10 min.

[0014] Optionally, the specific parameters for the immersion lifting in S6 are: immersion lifting speed of 5~10 mm / min, immersion time of 2~5 min, repeated three times.

[0015] The beneficial effects of this invention are: This invention successfully coated the LPBF-NiTi alloy surface with a PLA layer doped with Ca-Cur submicron modified material, which filled the porous structure of the Ag-DCPD film, hindered the penetration of corrosive media into the substrate, slowed down the degradation of the film, and improved the corrosion resistance of the film, thus providing a longer-term and more effective protection for the substrate. On the other hand, adding a layer of PLA doped with Ca-Cur submicron modified material to the surface of the Ag-DCPD film can fill the pores in the Ag-DCPD film, thus slowing down the Ag degradation in the early stages of the Ag-DCPD film. + The release of [the substance] reduced cytotoxicity, further improved membrane biocompatibility, and the membrane exhibited better cell activity and osteogenic capacity. Ag + In synergy with Cur, it further enhances the antibacterial effect of the membrane, showing a more significant inhibitory effect on the growth of Staphylococcus aureus and Escherichia coli. Moreover, the membrane can more effectively induce macrophages to polarize to the M2 phenotype, thereby enhancing their ability to promote tissue healing. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic flowchart of the method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an Ag-DCPD film in an embodiment of the present invention. Figure 2These are electron microscope (EM) surface morphology images, where (a), (b), (c), and (d) are EEM surface morphology images of samples 1, 2, 3, and 4, respectively. Figure 3 The figures are electrochemical analysis diagrams, where (a) is a polarization curve and (b) is a Nyquist curve. Figure 4 This is a graph showing the results of in vitro cell viability testing; Figure 5 The results of in vitro antibacterial activity detection are shown in the figure. (a) and (b) are the results of plate coating experiment and the inhibition rate curve of Staphylococcus aureus and Escherichia coli, respectively. Figure 6 The results are immunofluorescence staining results, where (a) is the fluorescence intensity of iNOS and (b) is the fluorescence intensity of Arg-1. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of them. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present application can be combined with each other.

[0018] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0019] Example 1: This embodiment provides a method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of a nickel-titanium alloy Ag-DCPD film, referring to... Figure 1 The method includes: S1, Substrate Manufacturing: A nickel-titanium alloy was manufactured using laser powder bed melting (LPBF) additive manufacturing technology to obtain an LPBF-NiTi alloy matrix.

[0020] S2, LPBF-NiTi alloy matrix pretreatment: The obtained LPBF-NiTi alloy substrate was polished with 80~800# sandpaper (such as 80#, 180#, 240#, 400#, 600#, 800#) to remove surface oil and uneven oxide film. After polishing, it was ultrasonically treated in anhydrous ethanol and deionized water for 20 min and then dried.

[0021] S3, Preparation of Ag-DCPD film on LPBF-NiTi alloy substrate: Electrochemical deposition was performed using a two-electrode mode with electrochemical operation. A pretreated LPBF-NiTi alloy substrate was used as the cathode, and a platinum sheet as the anode. The distance between the anode and cathode was 1–3 cm. Electrochemical deposition was carried out in an electrolyte solution at a preset temperature (10–60 °C) and a preset current density (0.1–5 mA / cm²). 2 The deposition process takes 10 to 90 minutes to form an Ag-DCPD film.

[0022] Electrolyte solutions contain Ag + Ca 2+ PO4 3- The solution consists of: 0.05–0.15 mol / L Ca(NO3)2·4H2O, 0.001–0.012 mol / L AgNO3 (2%–8% of Ca(NO3)2·4H2O), 0.03–0.09 mol / L NH4H2PO4 (0.6 times the amount of Ca(NO3)2·4H2O), and 0.3 vol% H2O2 in aqueous solution. When preparing the electrolyte solution, AgNO3 and Ca(NO3)2·4H2O must be completely dissolved in deionized water before adding NH4H2PO4.

[0023] After deposition, the substrate was rinsed with deionized water and dried at room temperature to obtain the LPBF-NiTi alloy substrate with deposited Ag-DCPD film.

[0024] S4, Preparation of Ca-Cur submicron modified materials: CaCl2 and curcumin (Cur) were completely dissolved in anhydrous ethanol, with the concentration of CaCl2 in the solution being 0.1~0.2 mol / L. After the CaCl2 was completely dissolved in the anhydrous ethanol, curcumin was added, with a concentration of 1~2 mg / mL. The solution was placed in a sealed container containing (NH4)2CO3 (the weight of (NH4)2CO3 added to the sealed container was 10 times that of curcumin) and placed in a constant temperature water bath at 55~65 ℃ for 4~8 h. After the reaction was completed, the turbid anhydrous ethanol solution was removed and centrifuged at a speed of 4000 rpm or higher for 10 min. After centrifugation, the precipitate was washed three times with distilled water, and centrifuged after each washing. The obtained solid was dried under vacuum conditions (temperature 40~60 ℃, drying time 24 h or higher) to obtain Ca-Cur submicron modified material.

[0025] S5, Preparation of the extract: Polylactic acid (PLA) particles were dissolved in dichloromethane (DCM) (the concentration of PLA in the resulting solution was 5 wt%~20 wt%), and then Ca-Cur submicron modified material was dispersed in it (the concentration of Ca-Cur submicron modified material in the resulting solution was 1~10 mg / mL) to obtain an extract.

[0026] The submicron modified material was dispersed by magnetic stirring at 300-500 rpm for 20 minutes, followed by ultrasonic treatment for 10 minutes.

[0027] S6, Preparation of composite film: The LPBF-NiTi alloy substrate with deposited Ag-DCPD film was immersed in the leaching solution at a fixed speed (5~10 mm / min) (immersion time 2~5 min) and then pulled up. This process was repeated three times, and the substrate was dried at room temperature to form an Ag-DCPD / PLA / Ca-Cur composite film. This completed the coating of the PLA layer with Ca-Cur submicron modified material on the surface of the Ag-DCPD film (resulting in the LPBF-NiTi alloy substrate coated with Ag-DCPD / PLA / Ca-Cur composite film).

[0028] Using the above method, the present invention successfully prepared a calcium-based curcumin (Ca-Cur) submicron modified material, and coated a polylactic acid (PLA) layer doped with calcium-based curcumin (Ca-Cur) submicron modified material onto the surface of a laser powder bed molten nickel-titanium (LPBF-NiTi) alloy with a silver-doped dicalcium dihydrate (Ag-DCPD) film deposited thereon.

[0029] This invention first utilizes calcium-based submicron materials as carriers for Cur to improve its hydrophilicity, synthesizing Ca-Cur submicron materials. Second, a PLA layer doped with Ca-Cur submicron materials is coated onto the surface of an LPBF-NiTi alloy with a deposited Ag-DCPD film. The resulting composite film aims to synergistically enhance the corrosion resistance and overall bone-promoting properties of the Ag-DCPD film, and also allows Ag to... + The synergistic effect with Cur further enhances the inhibitory effect on bacterial growth.

[0030] Example 2: This embodiment provides an LPBF-NiTi alloy matrix, comprising: S1, Substrate fabrication: NiTi alloy was fabricated using laser powder bed melting additive manufacturing technology to obtain LPBF-NiTi alloy matrix; S2, Pretreatment of LPBF-NiTi alloy matrix: Polished with 80#, 180#, 240#, 400#, 600# and 800# sandpaper, then ultrasonically treated in anhydrous ethanol and deionized water for 20 min respectively, and then taken out and blown dry to obtain LPBF-NiTi alloy matrix, i.e. sample 1.

[0031] like Figure 2 (a) shows the surface morphology of sample 1 under an electron microscope, where strip-shaped scratches formed by grinding can be observed.

[0032] Example 3: This embodiment provides an LPBF-NiTi alloy substrate coated with an Ag-DCPD film, comprising: S1, Substrate fabrication: NiTi alloy was fabricated using laser powder bed melting additive manufacturing technology to obtain LPBF-NiTi alloy matrix; S2, Pretreatment of LPBF-NiTi alloy matrix: Polished with 80#, 180#, 240#, 400#, 600# and 800# sandpaper, then ultrasonically treated in anhydrous ethanol and deionized water for 20 min respectively, and then taken out and dried to obtain LPBF-NiTi alloy matrix; S3, an Ag-DCPD film was prepared on the surface of an LPBF-NiTi alloy substrate: 0.1 mol / L Ca(NO3)2·4H2O, 0.004 mol / L AgNO3, 0.06 mol / L NH4H2PO4, and 0.3 vol% H2O2 were sequentially added to deionized water and stirred until completely dissolved to obtain an electrolyte solution. Electrochemical deposition was then performed in the electrolyte solution using a two-electrode mode, with the pretreated LPBF-NiTi alloy substrate as the cathode and a platinum sheet as the anode. The distance between the anode and cathode was maintained at 2 cm. The deposition was carried out at 25 °C and 1 mA / cm². 2 The sample was deposited at a current density of 30 min, rinsed with deionized water, and dried at room temperature to obtain the LPBF-NiTi alloy substrate with deposited Ag-DCPD film, i.e., sample 2.

[0033] like Figure 2 (b) shows the surface morphology of sample 2 under an electron microscope. Typical scaly structures and uniformly distributed silver-related dendritic white deposits can be observed on the surface, indicating that the Ag-DCPD film was successfully prepared.

[0034] Example 4: This embodiment provides an LPBF-NiTi alloy substrate coated with an Ag-DCPD / PLA film, comprising: S1, Substrate fabrication: NiTi alloy was fabricated using laser powder bed melting additive manufacturing technology to obtain LPBF-NiTi alloy matrix; S2, LPBF-NiTi alloy matrix pretreatment: polished with 80#, 180#, 240#, 400#, 600# and 800# sandpaper, then ultrasonically treated in anhydrous ethanol and deionized water for 20 min respectively, and then taken out and blown dry; S3, an Ag-DCPD film was prepared on the surface of an LPBF-NiTi alloy substrate: 0.1 mol / L Ca(NO3)2·4H2O, 0.004 mol / L AgNO3, 0.06 mol / L NH4H2PO4, and 0.3 vol% H2O2 were sequentially added to deionized water and stirred until completely dissolved to obtain an electrolyte solution. Electrochemical deposition was then performed in the electrolyte solution using a two-electrode mode, with the pretreated LPBF-NiTi alloy substrate as the cathode and a platinum sheet as the anode. The distance between the anode and cathode was maintained at 2 cm. The deposition was carried out at 25 °C and 1 mA / cm². 2 Deposited at a current density of 30 min, the sample was rinsed with deionized water and dried at room temperature; S4, Preparation of extract: Dissolve 10 wt% PLA particles in dichloromethane (DCM) to obtain the extract; S5, Preparation of composite film: The LPBF-NiTi alloy with deposited Ag-DCPD film was immersed in the leaching solution at a speed of 10 mm / min. After 2 min, the sample was pulled out at a speed of 10 mm / min and dried at room temperature for 10 min. This process was repeated three times and then naturally dried at room temperature to obtain the LPBF-NiTi alloy substrate coated with Ag-DCPD / PLA film, i.e., sample 3.

[0035] like Figure 2 (c) shows the surface morphology of sample 3 under an electron microscope. It can be observed that compared with sample 2, its morphology has changed significantly. The dendritic white precipitate has disappeared, the scaly pores have been sealed, and the surface is more uniform and dense, indicating that the Ag-DCPD / PLA film has been successfully prepared.

[0036] Example 5: This embodiment provides an LPBF-NiTi alloy substrate coated with an Ag-DCPD / PLA / Ca-Cur composite film, comprising: S1, Substrate fabrication: NiTi alloy was fabricated using laser powder bed melting additive manufacturing technology to obtain LPBF-NiTi alloy matrix; S2, LPBF-NiTi alloy matrix pretreatment: polished with 80#, 180#, 240#, 400#, 600# and 800# sandpaper, then ultrasonically treated in anhydrous ethanol and deionized water for 20 min respectively, and then taken out and blown dry; S3, an Ag-DCPD film was prepared on the surface of an LPBF-NiTi alloy substrate: 0.1 mol / L Ca(NO3)2·4H2O, 0.004 mol / L AgNO3, 0.06 mol / L NH4H2PO4, and 0.3 vol% H2O2 were sequentially added to deionized water and stirred until completely dissolved to obtain an electrolyte solution. Electrochemical deposition was then performed in the electrolyte solution using a two-electrode mode, with the pretreated LPBF-NiTi alloy substrate as the cathode and a platinum sheet as the anode. The distance between the anode and cathode was maintained at 2 cm. The deposition was carried out at 25 °C and 1 mA / cm². 2 Deposited at a current density of 30 min, the sample was rinsed with deionized water and dried at room temperature; S4, Preparation of Ca-Cur submicron modified material: 0.15 mol / L CaCl2 and 1.5 mg / mL Cur were completely dissolved in 75 mL of anhydrous ethanol and placed in a sealed beaker containing 2 g of (NH4)2CO3. The beaker was placed in a 60℃ water bath and reacted for 4 h. The anhydrous ethanol turbidity was then collected, centrifuged at 5000 rpm for 10 min, and the supernatant was removed. The precipitate was then washed three times with distilled water, centrifuged at 5000 rpm for 10 min after each wash. Finally, the obtained solid was dried under vacuum at 50℃ for 24 h to obtain the Ca-Cur submicron modified material. S5, Preparation of extract: 10 wt% PLA particles were added to dichloromethane (DCM) and completely dissolved. Then, 4 mg / mL of Ca-Cur submicron modified material was added to it. The mixture was magnetically stirred at 300~500 rpm for 20 min and ultrasonically treated for 10 min to make the Ca-Cur submicron modified material evenly dispersed, thus obtaining the extract. S6, Preparation of composite film: The LPBF-NiTi alloy with deposited Ag-DCPD film was immersed in the leaching solution at a speed of 10 mm / min. After 2 min, the sample was pulled out at a speed of 10 mm / min and dried at room temperature for 10 min. This process was repeated three times and then naturally dried at room temperature to obtain the LPBF-NiTi alloy substrate coated with Ag-DCPD / PLA / Ca-Cur composite film, i.e., sample 4.

[0037] like Figure 2 (d) shows the surface morphology of sample 4 under an electron microscope, where it can be observed that the Ca-Cur submicron modified material is effectively encapsulated and uniformly embedded in the PLA layer. Figure 2 (d) The small image in the upper right corner is a transmission electron microscope image of the Ca-Cur submicron modified material, indicating that the Ag-DCPD / PLA / Ca-Cur film was successfully prepared.

[0038] Figure 2 The images show a comparison of the surface morphology of samples 1-4 under electron microscopy. It can be seen that the PLA layer doped with Ca-Cur submicron modified material was successfully coated on the surface of the LPBF-NiTi alloy substrate with deposited Ag-DCPD.

[0039] Figure 3 This is an electrochemical analysis graph for evaluating the corrosion resistance of samples 1-4. Generally, a larger capacitance loop size in the Nyquist curve and a lower corrosion current density (Ig) in the potentiodynamic polarization curve indicate higher corrosion resistance. corr () indicates better corrosion resistance. Figure 3 (a) shows the potentiodynamic polarization curves of different samples. Compared with sample 2, samples 3 and 4 have lower Ig. corr. Figure 3 (b) shows the Nyquist plots for different samples. Compared to sample 2, samples 3 and 4 have larger capacitor circuit sizes. Sample 4 also has the largest capacitor circuit size and the lowest Ic. corr This study demonstrates that coating a PLA layer with Ca-Cur submicron modified material onto the surface of an LPBF-NiTi alloy substrate with deposited Ag-DCPD can significantly improve the corrosion resistance of the film and achieve longer-term stable protection of the alloy substrate.

[0040] Figure 4 This image shows the in vitro cell viability assay results for samples 1-4, used to assess biocompatibility. Generally, higher cell viability indicates better biocompatibility. Figure 4 As shown, compared to sample 2, samples 3 and 4 both exhibited higher cell activity, with sample 4 demonstrating the highest cell activity. This demonstrates that coating the surface of an Ag-DCPD-deposited LPBF-NiTi alloy substrate with a PLA layer doped with Ca-Cur submicron modified material effectively improves the biocompatibility of the membrane, benefiting cell adhesion and growth on the implant surface.

[0041] Figure 5 The graph shows the results of in vitro antibacterial activity testing of samples 1-4. *Escherichia coli* and *Staphylococcus aureus* were selected as representatives of Gram-negative and Gram-positive bacteria, respectively. Compared to sample 2, sample 4 showed a higher inhibition rate, achieving approximately 90% inhibition against both Gram-negative and Gram-positive bacteria. This demonstrates that Ag... + In synergy with Cur, it can effectively enhance the antibacterial ability of the membrane and improve its ability to inhibit the proliferation of Escherichia coli and Staphylococcus aureus.

[0042] Figure 6 Immunofluorescence staining results for the macrophage phenotypic markers iNOS (M1 type) and Arg-1 (M2 type) in samples 1-4 (Raw 264.7 macrophages). Compared with sample 1, the average fluorescence intensity of Arg-1 in samples 2-4 was significantly increased, with sample 4 showing the highest expression level, indicating a tendency towards M2 polarization. Conversely, sample 1 showed the highest average fluorescence intensity of iNOS, exhibiting typical M1 polarization characteristics. These results indicate that the constructed membrane material (Ag-DCPD / PLA / Ca-Cur composite membrane) can effectively guide macrophages towards M2 phenotypic polarization, thereby enhancing their potential to promote tissue repair and healing.

[0043] In summary, this invention coats a PLA layer doped with Ca-Cur submicron modified material onto the surface of an LPBF-NiTi alloy substrate with an already deposited Ag-DCPD film, preparing an Ag-DCPD / PLA / Ca-Cur composite film. This composite film is a multifunctional bio-coating exhibiting excellent corrosion resistance, cell compatibility, osteogenic properties, and antibacterial and anti-inflammatory effects, effectively improving the corrosion resistance of the Ag-DCPD film and achieving long-term stable protection of the alloy substrate. Furthermore, Cur and Ag... + The synergistic effect successfully enhanced the antibacterial properties of the membrane, achieving an inhibition rate of approximately 90% against Escherichia coli and Staphylococcus aureus. This significantly reduces the risk of infection during implantation and effectively guides macrophages towards the M2 phenotype. Coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an LPBF-NiTi alloy substrate with a deposited Ag-DCPD membrane enables Ag-DCPD membranes and laser powder bed melting additive manufacturing of nickel-titanium alloy implants to exhibit superior performance in the field of medical materials.

[0044] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0045] Those skilled in the art will understand that the purpose of this invention is to provide a relatively universal overall preparation process or technical principle, and to cover as many different applicable scenarios and conditions as possible (such as different raw material characteristics, production scale, product demand, etc.). Therefore, some specific operations can be flexibly adjusted according to the situation in actual implementation, as long as the expected or the same or similar technical effects as those in the embodiments of this invention can be achieved.

[0046] The steps in the method of this invention can be adjusted, combined, or deleted according to actual needs. The technical features can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the embodiments are described. However, as long as the combinations of these technical features do not contradict each other, they should all be considered within the scope of this invention.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method of coating a PLA layer of Ag-DCPD film layer surface with doped Ca-Cur submicron modified material, wherein, Ag-DCPD refers to silver-doped dicalcium phosphate dihydrate, Ca-Cur refers to calcium-based curcumin, and PLA refers to polylactic acid, and the method is characterized by comprising the following steps: S1, matrix manufacturing: a nickel-titanium alloy is manufactured by using a laser powder bed fusion additive manufacturing technology to obtain an LPBF-NiTi alloy matrix; S2, LPBF-NiTi alloy matrix pretreatment: the obtained LPBF-NiTi alloy matrix is polished, and then is sequentially subjected to ultrasonic treatment in anhydrous ethanol and deionized water, and is taken out and dried; S3, preparing Ag-DCPD film layer on the surface of LPBF-NiTi alloy substrate: using the double electrode mode of the electrochemical workstation, taking the pretreated LPBF-NiTi alloy substrate as the cathode and a platinum sheet as the anode, depositing in the electrolyte solution at a preset temperature and a preset current density to form an Ag-DCPD film layer, wherein the electrolyte solution comprises Ag + , Ca 2 + , PO4 3- , and after deposition, rinsing with deionized water and drying at room temperature to obtain an LPBF-NiTi alloy substrate with a deposited Ag-DCPD film layer; S4, preparation of Ca-Cur submicron modified material: CaCl2 and curcumin are sequentially dissolved in anhydrous ethanol, and then are placed in a sealed container containing (NH4)2CO3, and are placed in a constant-temperature water bath for reaction, after the reaction is completed, the anhydrous ethanol turbid liquid is taken out and subjected to centrifugal separation, the precipitate is washed with distilled water after each washing, and is subjected to centrifugal separation, and the obtained solid is dried under vacuum to obtain the Ca-Cur submicron modified material; S5, preparation of leaching solution: polylactic acid particles are dissolved in dichloromethane, and then the Ca-Cur submicron modified material is dispersed therein to obtain a leaching solution; S6, preparation of composite film layer: the LPBF-NiTi alloy matrix on which the Ag-DCPD film layer is deposited is repeatedly immersed and pulled in the leaching solution, and is dried at room temperature to form an Ag-DCPD / PLA / Ca-Cur composite film layer, and coating of the PLA layer doped with the Ca-Cur submicron modified material on the surface of the Ag-DCPD film layer is completed.

2. The method of claim 1, wherein the Ag-DCPD film layer surface coated PLA layer doped with Ca-Cur submicron modified material is characterized in that, In S2, the obtained LPBF-NiTi alloy matrix is polished by using 80-800# sandpaper to remove surface oil stains and uneven oxide film layers.

3. The method of claim 1, wherein the Ag-DCPD film layer surface coated PLA layer doped with Ca-Cur submicron modified material is characterized in that, The distance between the anode and the cathode in S3 is 1-3 cm, the preset temperature for deposition is 10-60°C, the preset current density is 0.1-5 mA / cm 2 , and the deposition time is 10-90 min.

4. The method of claim 1, wherein the Ag-DCPD film layer surface coated PLA layer doped with Ca-Cur submicron modified material is characterized in that, The electrolyte solution in S3 has the following composition: 0.05-0.15 mol / L Ca(NO3)2·4H2O, 0.001-0.012 mol / L AgNO3, 0.03-0.09 mol / L NH4H2PO4, and 0.3 vol% H2O2 aqueous solution.

5. The method of claim 4, wherein the Ag-DCPD film layer surface coated with the doped Ca-Cur submicron modified material PLA layer is characterized in that, In S3, after AgNO3 and Ca(NO3)2·4H2O are completely dissolved in deionized water, NH4H2PO4 can be added.

6. The method of claim 1, wherein the Ag-DCPD film layer surface coating of the Ca-Cur doped sub-micron modified PLA layer is characterized by, In S4, after being dissolved in anhydrous ethanol, the concentration of CaCl2 is 0.1-0.2 mol / L, and the concentration of curcumin is 1-2 mg / mL; curcumin is added after CaCl2 is completely dissolved in anhydrous ethanol; and the weight of (NH4)2CO3 in the sealed container is 10 times that of curcumin.

7. The method of claim 1, wherein the Ag-DCPD film layer surface coating of the Ca-Cur doped sub-micron modified PLA layer is characterized by, In S4, the temperature of the constant-temperature water bath is 55-65 ℃, the reaction time is 4-8 h; the centrifugal speed is higher than 4000 rpm, and the centrifugal time is 10 min each time; the vacuum drying temperature is 40-60 ℃, and the drying time is more than 24 h.

8. The method of claim 1, wherein the Ag-DCPD film layer surface coating of the Ca-Cur doped sub-micron modified PLA layer is characterized by, In S5, after polylactic acid particles are dissolved in dichloromethane, the concentration of polylactic acid in the obtained solution is 5 wt%-20 wt%, the concentration of the Ca-Cur submicron modified material dispersed therein is 1-10 mg / mL, the dispersion mode is 300-500 rpm magnetic stirring for 20 min, and then ultrasonic treatment is performed for 10 min.

9. The method of claim 1, wherein the Ag-DCPD film layer surface coated doped Ca-Cur submicron modified material PLA layer is characterized by, The specific parameters of dip-coating in S6 are as follows: dip-coating speed is 5-10 mm / min, soaking time is 2-5 min, and repeating three times.

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