Method for coating the surface of an ag-dcpd film layer with a layer of pla modified with ca-cur doped submicron materials

Abstract

The application discloses a method for coating a PLA layer of Ag-DCPD film layer surface with doped Ca-Cur submicron modified material, and relates to the technical field of medical material surface biological coating. The method comprises the following steps: an LPBF-NiTi alloy base is manufactured by using a laser powder bed fusion additive manufacturing technology and is pretreated; the pretreated LPBF-NiTi alloy base is subjected to electrochemical deposition in an electrolyte solution to obtain an LPBF-NiTi alloy base with a deposited Ag-DCPD film layer; CaCl2 and curcumin are dissolved in anhydrous ethanol, and are placed in a sealed container containing (NH4)2CO3 for constant-temperature reaction to obtain Ca-Cur submicron modified material; polylactic acid is dissolved in dichloromethane, and then the Ca-Cur submicron modified material is dispersed in the polylactic acid to obtain a leaching solution; the LPBF-NiTi alloy base with the deposited Ag-DCPD film layer is repeatedly immersed and pulled in the leaching solution to obtain an LPBF-NiTi alloy base coated with an Ag-DCPD / PLA / Ca-Cur composite film layer. Through the method, the corrosion resistance, biocompatibility and antibacterial and anti-inflammatory performance of the Ag-DCPD film layer are successfully improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of biological coating of medical material surfaces, and particularly relates to a method for coating a PLA layer of doped Ca-Cur submicron modified material on the surface of an LPBF-NiTi alloy on which an Ag-DCPD film layer has been deposited. BACKGROUND

[0002] With the deepening of the aging of the population, the demand for personalized medical treatment is increasingly highlighted, and the demand for customized implants is continuously increasing. In recent years, laser powder bed fusion (LPBF) technology can directly form dense metal parts with complex structures and high dimensional accuracy, and has become an important technical means for manufacturing high-performance medical implants. Among many biomedical metal materials, nickel-titanium (NiTi) alloy has a broad application prospect due to its unique shape memory effect, similar elastic modulus to human bone, and non-magnetic properties. However, there are problems such as insufficient release of Ni 2+ , biological inertia and insufficient antibacterial properties in the physiological environment, which may lead to failure of the final implantation surgery. Surface modification technology has been proven to be an effective strategy to improve the functionality of the metal surface. Ag-DCPD can be converted into hydroxyapatite (HAP) in the body, promote biomineralization and cell compatibility, and release Ag + for long-term and efficient antibacterial effect. However, the Ag-DCPD film layer has a porous scale structure, which provides a channel for the penetration of corrosive media to the substrate, thereby accelerating the degradation of the film layer and the corrosion of the substrate. Moreover, a large amount of Ag + released in the initial corrosion stage can cause cytotoxicity and hinder wound healing.

[0003] PLA, as a biodegradable polymer material, can effectively prevent the penetration of corrosive media to the metal substrate and has a certain slow-release effect. Therefore, coating a PLA layer on the surface of the Ag-DCPD film layer can not only improve the corrosion resistance of the film layer, but also reduce the release of Ag + during the degradation of the film layer to reduce cytotoxicity. However, due to the structure of the material and the film forming process, PLA cannot form an absolutely dense layer, and micro-nano materials can fill the "defects" in the organic film layer, prolong the penetration path of oxygen and water, and thus reduce the penetration of corrosive media in the environment and improve the protection effect of the film layer. Curcumin (Cur) is a natural polyphenolic substance extracted from plants in the ginger family, and has excellent antibacterial and anti-inflammatory properties. Doping Cur in the PLA layer not only fills the defects in the PLA layer and enhances the corrosion resistance of the film layer, but also makes up for the insufficient antibacterial properties of Ag +The decrease in bacteriostasis ability caused by the release reduction. However, the hydrophobicity of Cur seriously limits its antibacterial and anti-inflammatory effect. To solve this problem, a calcium-based sub-micron material with high loading capacity, good pH responsiveness, ideal biocompatibility and biodegradability is introduced as its carrier. Moreover, the calcium-based sub-micron material can act as a nucleation site to induce the deposition of phosphate mineralization products, further improving the corrosion resistance of the film layer.

[0004] Currently, there is no report on the use of Ag + There is no related report on the use of Ag-DCPD film layer surface coated with PLA layer doped with Ca-Cur sub-micron modified material to comprehensively improve the corrosion resistance, bone formation and antibacterial and anti-inflammatory properties of Ag-DCPD film layer in combination with Cur. SUMMARY

[0005] To solve the above technical problems, the application provides a method for coating a PLA layer doped with Ca-Cur sub-micron modified material on the surface of a nickel-titanium alloy Ag-DCPD film layer. First, the calcium-based sub-micron material is used as a carrier for Cur to improve its hydrophilicity, and the Ca-Cur sub-micron material is synthesized. Second, the PLA layer doped with Ca-Cur sub-micron material is coated on the surface of the LPBF-NiTi alloy with deposited Ag-DCPD film layer. The prepared composite film layer aims to synergistically improve the corrosion resistance and comprehensive performance of Ag-DCPD film layer, and can also inhibit the growth of bacteria through the synergistic effect of Ag + and Cur, further strengthening the inhibitory effect on bacterial growth.

[0006] According to one aspect of the application, a method for coating a PLA layer doped with Ca-Cur sub-micron modified material on the surface of an Ag-DCPD film layer is provided, wherein Ag-DCPD refers to silver-doped dihydrate dicalcium phosphate, Ca-Cur refers to calcium-based curcumin, and PLA refers to polylactic acid, comprising: S1, substrate manufacturing: manufacturing a nickel-titanium alloy by using a 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, and then ultrasonic treating in anhydrous ethanol and deionized water, respectively, and taking out for drying; S3, preparing an Ag-DCPD film layer on the surface of the LPBF-NiTi alloy substrate: using a double electrode mode of an electrochemical workstation for electrochemical deposition, taking the pretreated LPBF-NiTi alloy substrate as a cathode, and taking a platinum sheet as an anode, depositing in a pre-set temperature electrolyte solution at a pre-set current density to form an Ag-DCPD film layer, wherein the electrolyte solution comprises Ag + , Ca 2+ , and PO4 3-, after deposition, rinse with deionized water, dry at room temperature, to obtain the LPBF-NiTi alloy substrate with deposited Ag-DCPD film layer; S4, preparation of Ca-Cur sub-micron modified material: sequentially dissolve CaCl2 and curcumin in anhydrous ethanol, then put into a sealed container containing (NH4)2CO3, and place in a constant temperature water bath for reaction, after the reaction is completed, take out the anhydrous ethanol turbid liquid for centrifugal separation, after centrifugation, wash the precipitate with distilled water, and centrifuge after each washing, and dry the obtained solid under vacuum condition, to obtain the Ca-Cur sub-micron modified material; S5, preparation of leaching solution: dissolve polylactic acid particles in dichloromethane, and then disperse the Ca-Cur sub-micron modified material therein, to obtain the leaching solution; S6, preparation of composite film layer: repeatedly dip and pull the LPBF-NiTi alloy substrate with deposited Ag-DCPD film layer in the leaching solution, and dry at room temperature, to form an Ag-DCPD / PLA / Ca-Cur composite film layer, and complete the coating of the PLA layer doped with Ca-Cur sub-micron modified material on the surface of the Ag-DCPD film layer.

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

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

[0009] Optionally, the composition of the electrolyte solution in S3 is: 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.

[0010] Optionally, in S3, after AgNO3 and Ca(NO3)2·4H2O are completely dissolved in deionized water, NH4H2PO4 can be added.

[0011] Optionally, in S4, the concentration of CaCl2 dissolved in anhydrous ethanol is 0.1-0.2 mol / L, and the concentration of curcumin is 1-2 mg / mL, and 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:

[0016] 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.

[0017] 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.

[0018] 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

[0019] 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:

[0020] Figure 1A flowchart of the method for coating the surface of the Ag-DCPD film layer with the PLA layer doped with Ca-Cur submicron modified material in the embodiments of the present application is shown in Figure 1.

[0021] Figure 2 Figure 2 shows the electron microscope surface morphology of the samples, wherein (a), (b), (c), and (d) are the electron microscope surface morphology of samples 1, 2, 3, and 4, respectively.

[0022] Figure 3 Figure 3 shows the electrochemical analysis, wherein (a) is the polarization curve, and (b) is the Nyquist curve.

[0023] Figure 4 Figure 4 shows the in vitro cell viability detection results.

[0024] Figure 5 Figure 5 shows the in vitro antibacterial activity detection results, wherein (a) and (b) are the plate coating experiment results and the antibacterial rate curve of Staphylococcus aureus and Escherichia coli, respectively.

[0025] Figure 6 Figure 6 shows the immunofluorescence staining results, wherein (a) is the iNOS fluorescence intensity, and (b) is the Arg-1 fluorescence intensity. DETAILED DESCRIPTION

[0026] In order to enable persons skilled in the art to better understand the schemes of the present application, the technical schemes in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without making creative efforts shall fall within the scope of protection of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0027] In the specification and claims of the present application, the terms “comprise” and “have” and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, product, or device comprising a series of steps or units need not be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0028] Embodiment 1

[0029] The present embodiment provides a method for coating the surface of the Ag-DCPD film layer with the PLA layer doped with Ca-Cur submicron modified material, referring to Figure 1 The method comprises the following steps:

[0030] S1, substrate manufacturing:

[0031] A nickel-titanium alloy was manufactured using laser powder bed melting (LPBF) additive manufacturing technology to obtain an LPBF-NiTi alloy matrix.

[0032] S2, LPBF-NiTi alloy matrix pretreatment:

[0033] 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.

[0034] S3, Preparation of Ag-DCPD film on LPBF-NiTi alloy substrate:

[0035] 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.

[0036] 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.

[0037] 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.

[0038] S4, Preparation of Ca-Cur submicron modified materials:

[0039] CaCl2 and curcumin (Cur) are sequentially completely dissolved in anhydrous ethanol, the concentration of CaCl2 in the solution is 0.1-0.2 mol / L, after CaCl2 is completely dissolved in anhydrous ethanol, curcumin is added, the concentration of curcumin is 1-2 mg / mL, the solution is placed in a sealed container (10 times of (NH4)2CO3 by weight of curcumin is added in the sealed container) containing (NH4)2CO3, and is placed in a constant-temperature water bath at 55-65 ℃, and the reaction time is 4-8 h; after the reaction is completed, the anhydrous ethanol turbid solution is taken out and centrifuged at a speed of 4000 rpm or more for 10 min; after centrifugation, the precipitate is washed with distilled water for three times, centrifugation is carried out after each washing; and the obtained solid is dried under vacuum (temperature 40-60 ℃, drying time 24 h or more) to obtain Ca-Cur sub-micron modified material.

[0040] S5, preparation of leaching solution:

[0041] Polylactic acid (PLA) particles are dissolved in dichloromethane (DCM) (the concentration of polylactic acid in the obtained solution is 5 wt%-20 wt%), and then Ca-Cur sub-micron modified material is dispersed therein (the concentration of Ca-Cur sub-micron modified material in the obtained solution is 1-10 mg / mL) to obtain a leaching solution.

[0042] The dispersion mode of the sub-micron modified material is 300-500 rpm magnetic stirring for 20 min, and then ultrasonic treatment for 10 min.

[0043] S6, preparation of composite film layer:

[0044] The LPBF-NiTi alloy substrate on which the Ag-DCPD film layer is deposited is immersed (immersion time is 2-5 min) in the leaching solution at a fixed speed (5-10 mm / min) and pulled up, and the operation is repeated three times; and the LPBF-NiTi alloy substrate is dried at room temperature to form an Ag-DCPD / PLA / Ca-Cur composite film layer, and the coating of the PLA layer doped with Ca-Cur sub-micron modified material on the surface of the Ag-DCPD film layer is completed (an LPBF-NiTi alloy substrate coated with an Ag-DCPD / PLA / Ca-Cur composite film layer is obtained).

[0045] By the above method, the calcium-based curcumin (Ca-Cur) sub-micron modified material is successfully prepared, and a polylactic acid (PLA) layer doped with calcium-based curcumin (Ca-Cur) sub-micron modified material is coated on the surface of a laser powder bed fusion nickel-titanium (LPBF-NiTi) alloy on which a silver-doped dicalcium phosphate dihydrate (Ag-DCPD) film layer has been deposited.

[0046] The application first uses calcium-based sub-micron material as the carrier of Cur to improve its hydrophilicity, synthesizes Ca-Cur sub-micron material; second, on the surface of the LPBF-NiTi alloy deposited with Ag-DCPD film layer, coats the PLA layer doped with Ca-Cur sub-micron material, and the prepared composite film layer aims to synergistically improve the corrosion resistance and osteopromotion comprehensive performance of the Ag-DCPD film layer, and can further strengthen the inhibition effect on bacterial growth through the synergistic effect of Ag + and Cur.

[0047] Example 2:

[0048] This embodiment provides an LPBF-NiTi alloy substrate, comprising:

[0049] S1, substrate manufacturing: using laser powder bed fusion additive manufacturing technology to manufacture NiTi alloy to obtain an LPBF-NiTi alloy substrate;

[0050] S2, LPBF-NiTi alloy substrate pretreatment: using 80#, 180#, 240#, 400#, 600# and 800# sandpaper for grinding, then respectively ultrasonic treatment in anhydrous ethanol and deionized water for 20 min, and taking out and blowing dry to obtain the LPBF-NiTi alloy substrate, i.e., sample 1.

[0051] As Figure 2 shown in (a) is the electron microscope surface morphology diagram of sample 1, and the strip-shaped scratches formed due to grinding can be observed.

[0052] Example 3:

[0053] This embodiment provides an LPBF-NiTi alloy substrate coated with Ag-DCPD film layer, comprising:

[0054] S1, substrate manufacturing: using laser powder bed fusion additive manufacturing technology to manufacture NiTi alloy to obtain an LPBF-NiTi alloy substrate;

[0055] S2, LPBF-NiTi alloy substrate pretreatment: using 80#, 180#, 240#, 400#, 600# and 800# sandpaper for grinding, then respectively ultrasonic treatment in anhydrous ethanol and deionized water for 20 min, and taking out and blowing dry to obtain the LPBF-NiTi alloy substrate;

[0056] 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.

[0057] 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.

[0058] Example 4:

[0059] This embodiment provides an LPBF-NiTi alloy substrate coated with an Ag-DCPD / PLA film, comprising:

[0060] S1, Substrate fabrication: NiTi alloy was manufactured using laser powder bed melting additive manufacturing technology to obtain LPBF-NiTi alloy matrix;

[0061] 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;

[0062] 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;

[0063] S4, preparation of the leaching solution: 10 wt% of PLA particles were dissolved in dichloromethane (DCM) to obtain the leaching solution;

[0064] S5, composite film layer preparation: the LPBF-NiTi alloy with deposited Ag-DCPD film layer was immersed in the leaching solution at a speed of 10 mm / min, after 2 min, the sample was taken out at a speed of 10 mm / min, dried at room temperature for 10 min, repeated three times, and naturally dried at room temperature to obtain the LPBF-NiTi alloy substrate coated with Ag-DCPD / PLA film layer, i.e. sample 3.

[0065] As shown in Figure 2 (c) is the electron microscope surface morphology diagram of sample 3, it can be observed that compared with sample 2, the morphology is obviously changed, the dendritic white precipitate disappears, the scale structure pore is sealed, and the surface is more uniform and dense, indicating that the Ag-DCPD / PLA film layer is successfully prepared.

[0066] Example 5:

[0067] The present embodiment provides a LPBF-NiTi alloy substrate coated with Ag-DCPD / PLA / Ca-Cur composite film layer, comprising:

[0068] S1, substrate manufacturing: a NiTi alloy was manufactured by laser powder bed fusion additive manufacturing technology to obtain the LPBF-NiTi alloy substrate;

[0069] S2, LPBF-NiTi alloy substrate pretreatment: sanding was performed using 80#, 180#, 240#, 400#, 600# and 800# sandpaper, and then ultrasonic treatment was performed in anhydrous ethanol and deionized water for 20 min, respectively, and the sample was taken out and blown dry;

[0070] S3, preparation of Ag-DCPD film layer on the surface of the LPBF-NiTi alloy substrate: 0.1 mol / L of Ca(NO3)2·4H2O, 0.004 mol / L of AgNO3, 0.06 mol / L of NH4H2PO4 and 0.3 vol% of H2O2 were added to deionized water in sequence and stirred until completely dissolved to obtain an electrolyte solution, and then electrochemical deposition was performed in the electrolyte solution using a double electrode mode of an electrochemical working station, wherein the pretreated LPBF-NiTi alloy substrate was used as a cathode and a platinum sheet was used as an anode, the distance between the anode and the cathode was kept at 2 cm, and the deposition was performed at 25℃ under a current density of 1 mA / cm 2

[0071] ​S4, Preparation of Ca-Cur sub-micron 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 large beaker with 2 g of (NH4)2CO3, and the sealed large beaker was placed in a 60°C water bath for 4 h. The anhydrous ethanol turbid liquid was then collected, centrifuged at 5000 rpm for 10 min, the supernatant was removed, and then the precipitate was washed with distilled water three times, each time after washing, centrifuged at 5000 rpm for 10 min. Finally, the obtained solid was dried under vacuum at 50°C for 24 h to obtain the Ca-Cur sub-micron modified material;

[0072] S5, Preparation of the leaching solution: 10 wt% of PLA particles were added to dichloromethane (DCM), and after complete dissolution, 4 mg / mL of Ca-Cur sub-micron modified material was added, and the mixture was magnetically stirred at 300-500 rpm for 20 min, and then ultrasonically treated for 10 min to uniformly disperse the Ca-Cur sub-micron modified material, thereby obtaining the leaching solution;

[0073] S6, Preparation of the composite film layer: the LPBF-NiTi alloy on which the Ag-DCPD film layer was deposited was immersed in the leaching solution at a speed of 10 mm / min, after 2 min, the sample was taken out at a speed of 10 mm / min, and dried at room temperature for 10 min, and the above steps were repeated three times, and then naturally dried at room temperature to obtain the LPBF-NiTi alloy substrate coated with the Ag-DCPD / PLA / Ca-Cur composite film layer, i.e., sample 4.

[0074] As shown in Figure 2 (d) is the electron microscope surface morphology diagram of sample 4, it can be observed that the Ca-Cur sub-micron modified material is effectively wrapped and uniformly embedded in the PLA layer Figure 2 (d) The small graph in the upper right corner is the transmission electron microscope diagram of the Ca-Cur sub-micron modified material), indicating that the Ag-DCPD / PLA / Ca-Cur film layer is successfully prepared.

[0075] Figure 2 As shown in the electron microscope surface morphology comparison diagram of samples 1-4, it can be seen that the PLA layer doped with Ca-Cur sub-micron modified material is successfully coated on the surface of the LPBF-NiTi alloy substrate on which the Ag-DCPD is deposited.

[0076] Figure 3 As shown in the electrochemical analysis diagram for evaluating the corrosion resistance of samples 1-4. Generally, the larger the size of the capacitance loop in the Nyquist (Nyquist) curve diagram and the lower the corrosion current density (I corr ) in the potentiodynamic polarization curve diagram, the better the corrosion resistance. Figure 3(a) are potentiodynamic polarization curves of different samples, compared with sample 2, samples 3, 4 have lower I corr . Figure 3 (b) are Nyquist plots of different samples, compared with sample 2, samples 3, 4 have larger capacitive loop size. And sample 4 has the largest capacitive loop size and the lowest I corr , which proves that the PLA layer doped with Ca-Cur sub-micron modified material coated on the surface of the LPBF-NiTi alloy substrate on which Ag-DCPD has been deposited can greatly improve the corrosion resistance of the film layer and realize longer-term stable protection of the alloy substrate.

[0077] Figure 4 is a graph of in vitro cell viability detection results for biocompatibility detection of samples 1-4. Generally, higher cell viability represents better biocompatibility. As shown in Figure 4 , compared with sample 2, samples 3, 4 both have higher cell viability, among which, sample 4 shows the highest cell viability. It is proved that the PLA layer doped with Ca-Cur sub-micron modified material coated on the surface of the LPBF-NiTi alloy substrate on which Ag-DCPD has been deposited can effectively improve the biocompatibility of the film layer, which is beneficial to cell adhesion and growth on the surface of the implant.

[0078] Figure 5 is a graph of in vitro antibacterial activity detection results for samples 1-4, and Escherichia coli and Staphylococcus aureus are selected as representatives of gram-negative bacteria and gram-positive bacteria for detection. Compared with sample 2, sample 4 has a higher bacteriostatic rate, and the bacteriostatic rate of gram-negative bacteria and gram-positive bacteria can reach about 90%. It is proved that the synergistic effect of Ag + and Cur can effectively improve the bacteriostatic ability of the film layer and improve the inhibition ability of the proliferation of Escherichia coli and Staphylococcus aureus.

[0079] Figure 6 is the immunofluorescence staining results of Raw 264.7 macrophage phenotype markers iNOS (M1 type) and Arg-1 (M2 type) in samples 1-4. Compared with sample 1, the average fluorescence intensity of Arg-1 of samples 2-4 is significantly increased, among which, sample 4 has the highest expression level, indicating that it tends to M2 type polarization state. On the contrary, the average fluorescence intensity of iNOS of sample 1 is the highest, showing typical M1 type polarization characteristics. The results show that the constructed film layer material (Ag-DCPD / PLA / Ca-Cur composite film layer) can effectively guide the polarization of macrophages to M2 phenotype, thereby enhancing its potential to promote tissue repair and healing.

[0080] In summary, the application coats the surface of the LPBF-NiTi alloy substrate on which the Ag-DCPD film layer has been deposited with the PLA layer doped with Ca-Cur submicron modified material, and prepares the Ag-DCPD / PLA / Ca-Cur composite film layer, which is a multifunctional composite biological coating with excellent corrosion resistance, cell compatibility, bone formation ability and antibacterial and anti-inflammatory performance, effectively improves the corrosion resistance of the Ag-DCPD film layer, and realizes long-term stable protection of the alloy substrate. In addition, Cur and Ag + synergistic effect, successfully improves the antibacterial performance of the film layer, and the inhibition rate of Escherichia coli and Staphylococcus aureus can reach about 90%, which can greatly reduce the risk of infection during implantation, and can effectively guide the polarization of macrophages to M2 phenotype. Coating the surface of the LPBF-NiTi alloy substrate on which the Ag-DCPD film layer has been deposited with the PLA layer doped with Ca-Cur submicron modified material can make the Ag-DCPD film layer and the laser powder bed fusion additive manufacturing nickel-titanium alloy implant have better application performance in the field of medical materials.

[0081] The above-mentioned embodiment numbers of the application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0082] Those skilled in the art should understand that the purpose of the present application 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 during actual implementation, as long as the expected or the same or similar technical effects as in the embodiments of the present application can be achieved.

[0083] The steps in the method of the embodiments of the present application can be adjusted in sequence, combined and deleted according to actual needs. Each technical feature can be combined arbitrarily, and in order to make the description simple, all possible combinations of technical features in the embodiments are not described, however, as long as the combinations of technical features do not exist contradictory, they should be considered as the scope of the present application.

[0084] The above-mentioned only is the preferred embodiment of the present application, it should be pointed out, for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an Ag-DCPD film, wherein, Ag-DCPD refers to silver-doped dicalcium phosphate dihydrate, Ca-Cur refers to calcium-based curcumin, and PLA refers to polylactic acid. The feature is that it comprises: S1, Substrate fabrication: NiTi alloy was manufactured using laser powder bed fusion additive manufacturing technology to obtain an LPBF-NiTi alloy matrix; S2, Pretreatment of LPBF-NiTi alloy matrix: The obtained LPBF-NiTi alloy matrix is ​​polished, and then ultrasonically treated in anhydrous ethanol and deionized water in sequence, and then taken out and dried. S3, Preparation of Ag-DCPD film on LPBF-NiTi alloy substrate: Electrochemical deposition was performed using a dual-electrode mode on an electrochemical workstation. The pretreated LPBF-NiTi alloy substrate was used as the cathode, and a platinum sheet was used as the anode. Deposition was carried out in an electrolyte solution at a preset temperature and a preset current density to form an Ag-DCPD film. The electrolyte solution contained 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. The mixture was placed in a constant temperature water bath for reaction. After the reaction was completed, the turbid anhydrous ethanol liquid was taken out 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 Ca-Cur submicron modified material. S5, Preparation of extract: Polylactic acid particles are dissolved in dichloromethane, and then Ca-Cur submicron modified material is dispersed in it to obtain extract; S6, Composite film preparation: The LPBF-NiTi alloy substrate with deposited Ag-DCPD film is repeatedly immersed and pulled in the leaching solution and dried at room temperature to form Ag-DCPD / PLA / Ca-Cur composite film, thus completing the coating of the PLA layer with Ca-Cur submicron modified material on the surface of the Ag-DCPD film.

2. The method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an Ag-DCPD film according to claim 1, characterized in that, In S2, the obtained LPBF-NiTi alloy substrate is polished with 80~800# sandpaper to remove surface oil and uneven oxide film.

3. The method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an Ag-DCPD film according to claim 1, characterized in that, In S3, the distance between the anode and cathode is 1~3cm, the preset deposition temperature is 10~60℃, and the preset current density is 0.1~5mA / cm. 2 The deposition time is 10~90 min.

4. The method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an Ag-DCPD film according to claim 1, characterized in that, The electrolyte solution in S3 consists 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 an aqueous solution of 0.3 vol% H2O2.

5. The method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of the Ag-DCPD film according to claim 4, characterized in that, When preparing the electrolyte solution in S3, NH4H2PO4 can only be added after AgNO3 and Ca(NO3)2·4H2O have completely dissolved in deionized water.

6. The method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an Ag-DCPD film according to claim 1, characterized in that, 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.

7. The method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an Ag-DCPD film according to claim 1, characterized in that, 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.

8. The method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an Ag-DCPD film according to claim 1, characterized in that, The concentration of polylactic acid in the solution obtained after dissolving polylactic acid particles in dichloromethane in S5 is 5 wt%~20 wt%. The concentration of Ca-Cur submicron modified material dispersed in it 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.

9. The method for coating a PLA layer doped with Ca-Cur submicron modified material onto the surface of an Ag-DCPD film according to claim 1, characterized in that, The specific parameters for the S6 immersion lifting process are as follows: immersion lifting speed is 5~10 mm / min, immersion time is 2~5 min, and the process is repeated three times.

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