CN108796491B - A kind of magnesium-based metal conversion coating with high corrosion resistance and surface functionalization and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of with highly corrosion resistant and surface-functionalized magnesium-base metal conversion coating and preparation method thereof.Method includes the following steps: (1) pre-processes magnesium alloy base material；(2) pretreated magnesium alloy is placed in poly- positive electricity electrolyte solution, after reacting 1~30min, takes out and cleaned with deionized water；(3) products therefrom in step (2) is placed in the mixed solution of polyphenolic substance and poly- negative electrolyte, after reacting 1~30min, takes out and cleaned with deionized water；(4) using step (3) products therefrom as substrate, step (2)~(3) are repeated described process 10~100 times, and dry with nitrogen, obtains conversion coating.The method of the present invention is easy to operate, at low cost, and universality is wide, is suitable for the area researches such as magnesium-based intravascular stent and bone immobilizing material.

Description

A magnesium-based metal conversion coating with high corrosion resistance and surface functionalization and the same Preparation

technical field

The invention belongs to the field of medical materials, in particular to a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization and a preparation method thereof, which can be used for magnesium-based fully degradable orthopaedic implant materials and fully degradable magnesium-based alloy blood vessel stents Material modification research.

Background technique

Compared with traditional biomedical stainless steel, titanium alloy and other metal materials, magnesium-based metal materials have many advantages such as good biocompatibility, mechanical properties, biodegradability, low thrombogenicity, and low inflammatory response, which are widely expected to be studied. It is used in blood stent materials, orthopedic repair materials, etc. Although degradable magnesium alloy has its unique advantages, its special problem is that the degradation rate is too fast, and the degradation has been basically completed within three months. At the same time, although the physicochemical properties and biocompatibility of degradable magnesium alloy materials are close to or even better than those of inert metal materials, long-term service in a humid physiological environment, the rapid degradation rate of magnesium alloys can easily lead to implants. Premature loss of stress support. Hydrogen evolution corrosion occurs in magnesium alloys in the body, and the local pH of the body tissue increases, which is not conducive to the growth of surrounding tissues.

At present, the methods used to improve the corrosion resistance of magnesium alloys mainly include bulk modification (alloying and microstructure adjustment) and surface modification. The bulk modification is mainly by adding a small amount of trace elements such as Zn, Ca, Mn, etc. into the magnesium metal, which can effectively improve the mechanical properties and corrosion resistance of the alloy by adjusting the crystal phase structure and grain size of the metal. , the alloy prepared by this method has good biocompatibility, but there are defects such as excessive cost and low repeatability. Surface modification is currently the most effective method for surface modification of magnesium alloys, which can take into account the control of corrosion of magnesium alloys and biodegradability. At present, the development of a magnesium alloy conversion coating with good corrosion resistance and good surface biocompatibility is still an urgent problem to be solved for fully degradable magnesium-based metal stent materials.

Commonly used magnesium alloy surface modification coatings are non-covalent bonds, which are easily affected by external factors such as environmental pH, temperature, and salt ions, resulting in sudden drug release, coating damage, accelerated corrosion, and shortened implant service life. life.

SUMMARY OF THE INVENTION

In view of the above deficiencies in the prior art, the present invention provides a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization and a preparation method thereof, which can effectively solve the problem that the existing magnesium-based conversion coating is easily affected by a humid environment Corrosion rates are too fast, causing stress fractures and problems affecting surrounding tissue growth.

For realizing the above-mentioned purpose, the technical scheme that the present invention solves its technical problem adopts is:

A preparation method of a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization, comprising the following steps:

(1) Pretreatment of magnesium alloy base material;

(2) The pretreated magnesium alloy is placed in a polycationic electrolyte solution with a pH value of 0.01 to 1 mM and a pH of 4 to 10. After reacting at 4 to 37 ° C for 1 to 30 minutes, take it out and wash it with deionized water for 3 to 5 times. ;

(3) The product obtained in step (2) is placed in a mixed solution of 0.01-20 mM polyphenol compound and polyanion electrolyte with a pH value of 5.5-8.5, reacted at 4-37 ° C for 1-30 min, taken out and used up Washing with ionized water 3 to 5 times; wherein, the molar ratio of the polyphenol compound and the polyanion electrolyte is 1 to 2: 1 to 2;

(4) Using the product obtained in step (3) as a substrate, repeating the process described in steps (2) to (3) for 10 to 100 times, and drying with nitrogen to obtain a conversion coating.

Further, in step (1), the magnesium alloy is pure magnesium, magnesium rare earth alloy, novel biomedical magnesium alloy or magnesium aluminum alloy.

Among them, the magnesium rare earth alloy is AZ31 magnesium alloy, AZ91 magnesium alloy or WE43 magnesium alloy.

Among them, the new biomedical magnesium alloy is AE21 magnesium alloy, Mg-Mn-Zn alloy or Mg-Si alloy.

Further, in step (2), the polycation electrolyte is poly-L-lysine hydrobromide, polyallylamine hydrochloride, poly-L-arginine hydrochloride, polyethyleneimine, shell Glycans, polyhexyl violet nitrile or gentamicin and kanamycin sulfate.

Further, the molar ratio of the polyphenol compound and the polyanion electrolyte in step (3) is 1:1.

Further, in step (3), the polyphenolic compound is epicatechin, epigallocatechin, epigallocatechin gallate, epicatechin gallate, gallic acid, resveratrol, vitamin B2 , tanshinone, flavonoids, curcumin or tannins.

Further, in step (3), the polyanion electrolyte is heparin, heparan sulfate, hyaluronic acid, chondroitin sulfate, collagen, dextran, keratan sulfate, polyacrylic acid, polystyrene sulfonate sodium salt, alginic acid Sodium, polyglutamic acid or deoxyribonucleic acid.

Further, the concentration of the polycation electrolyte is 0.01-1 mM, and the pH is 7.4; the concentration of the mixed solution is 0.001-20 mM, and the pH is 7.2.

The magnesium-based metal conversion coating with high corrosion resistance and surface functionalization prepared by the above method.

The effective effects of the present invention are:

1. Since polyphenolic compounds can form stable polymer coatings with polycationic electrolytes and polyanionic electrolytes through hydrogen bonding, π-π interaction and local covalent bonding, the present invention is based on the principle of layer-by-layer self-assembly. The technology enables the polycationic electrolyte and polyphenol/polyanionic electrolyte composite to form a dense and uniform cross-linked network coating on the surface of the magnesium alloy material. The prepared conversion coating has strong bonding force with the substrate and good corrosion resistance. .

2. The molecular structure of polyphenol compounds contains a large number of vicinal phenolic hydroxyl groups, which can chelate with magnesium, zinc, manganese and other ions generated by the corrosion of stents, and assist the effective conversion of such metal ions that are corroded on the surface of magnesium-based materials Deposition can effectively avoid further corrosion of the coating.

3. Polyphenolic compounds, especially tea polyphenols, can protect vascular endothelial cells from oxidative stress damage due to their good antioxidant capacity. In the process of magnesium-based material degradation, polyphenolic metal complexes with antioxidant properties Free release can maintain the normal redox balance in local blood vessels within a certain range; at the same time, polyphenol compounds themselves have good biocompatibility, and the use of plant polyphenols to intervene in the construction of organic transformation layers can not only effectively improve The overall corrosion resistance of the coating can also introduce a variety of functional groups, which is beneficial to the subsequent drug loading and immobilization of biomolecules.

4. The coating to be prepared in the present invention is usually less than 100 nm, the obtained coating is uniform, the input of raw materials required for preparing the coating is very small, the amount of raw materials added is easy to control, and the prepared coating can be applied on the surface of a variety of materials. Modification, compared with traditional corrosion mitigation coating technology, is simple to operate, low cost and widely applicable.

Description of drawings

Fig. 1 is the atomic force microscope (Atomic Force Microscope, AFM) detection result figure of the conversion coating prepared by the present invention;

Figure 2 is a graph showing the anticoagulant properties of the conversion coating prepared by the present invention.

Detailed ways

The specific embodiments of the present invention are described below to facilitate those skilled in the art to understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes Such changes are obvious within the spirit and scope of the present invention as defined and determined by the appended claims, and all inventions and creations utilizing the inventive concept are within the scope of protection.

Example 1

A preparation method of a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization, comprising the following steps:

(1) Polishing, cleaning and drying the pure magnesium material to be modified;

(2) placing the product obtained in step (1) in a polyethyleneimine solution with a concentration of 0.01 mM and a pH of 7.4, reacting at 4° C. for 2 min, then taking it out, and washing it with deionized water 3 times;

(3) the product obtained in step (2) is placed in a mixed solution of epicatechin and heparan sulfate with a concentration of 0.2 mM and a pH value of 7.5, reacted at 10 ° C for 5 min, then taken out, and washed with deionized water for 3 time; wherein, the mol ratio of epicatechin and heparan sulfate is 1:2;

(4) Using the product obtained in step (3) as the substrate, repeating the process described in steps (2) to (3) for 60 times, drying with nitrogen, and then storing in a vacuum drying oven, the conversion with corrosion resistance can be obtained. coating.

Example 2

A preparation method of a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization, comprising the following steps:

(1) Polishing, cleaning and drying the magnesium-zinc-manganese alloy to be modified;

(2) placing the product obtained in step (1) in a polyhexyl violet nitrile solution with a concentration of 0.01 mM and a pH value of 7.5, reacting at 5°C for 2 min, then taking it out, and washing with deionized water 3 times;

(3) the product obtained in step (2) is placed in a mixed solution of epigallocatechin gallate and dermatan sulfate with a concentration of 0.02 mM and a pH value of 7.8, reacted at 15° C. for 5 min, then taken out, and used for Ionized water was washed 3 times; wherein, the molar ratio of epigallocatechin gallate to dermatan sulfate was 1:1;

(4) Using the product obtained in step (3) as the substrate, repeating the process described in steps (2) to (3) 3 times, drying with nitrogen, and then storing in a vacuum drying oven, the conversion with corrosion resistance can be obtained. coating.

Example 3

A preparation method of a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization, comprising the following steps:

(1) Polishing, cleaning and drying the WE43 magnesium alloy to be modified;

(2) placing the product obtained in step (1) in a chitosan solution with a concentration of 0.01 mM and a pH of 7.4, reacting at 5°C for 2 min, then taking it out, and washing it with deionized water 3 times;

(3) placing the product obtained in step (2) in a mixed solution of epicatechin gallate and chondroitin sulfate with a concentration of 0.05mM and a pH of 7.2, reacting at 10°C for 5min, then taking out, and deionized Washed with water 3 times; wherein, the molar ratio of epicatechin gallate to chondroitin sulfate is 1.5:2;

(4) Using the product obtained in step (3) as the substrate, repeating the process described in steps (2) to (3) for 5 times, drying with nitrogen, and then storing in a vacuum drying oven, the transformation with corrosion resistance can be obtained. coating.

Example 4

A preparation method of a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization, comprising the following steps:

(1) Polishing, cleaning and drying the WE43 magnesium alloy that needs to be modified for use;

(2) placing the product obtained in step (1) in a polyhexyl violet nitrile solution with a concentration of 0.05 mM and a pH value of 7.6, reacting at 5°C for 2 min, then taking out, and washing with deionized water 3 times;

(3) placing the product obtained in step (2) in a mixed solution of gallic acid and dextran with a concentration of 0.4 mM and a pH of 7.4, reacting at 20° C. for 5 min, then taking out, and washing with deionized water 3 times; Wherein, the molar ratio of gallic acid and glucan is 2:1;

(4) Using the product obtained in step (3) as the substrate, repeating the process described in steps (2) to (3) for 20 times, drying with nitrogen, and then storing in a vacuum drying oven, the transformation with corrosion resistance can be obtained. coating.

Example 5

A preparation method of a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization, comprising the following steps:

(1) Polishing, cleaning and drying the WE43 magnesium alloy to be modified;

(2) The product obtained in step (1) was placed in a poly-L-arginine hydrochloride solution with a concentration of 0.02 mM and a pH value of 7.4, reacted at 4°C for 1 min, then taken out, and washed with deionized water for 3 Second-rate;

(3) The product obtained in step (2) was placed in a mixed solution of theaflavins and polystyrene sulfonic acid sodium salt with a concentration of 0.002 mM and a pH value of 7.4, reacted at 10 ° C for 5 min, then taken out, and deionized Washed with water 3 times; wherein, the molar ratio of theaflavins to polystyrene sulfonic acid sodium salt is 1:1;

(4) Using the product obtained in step (3) as the substrate, repeating the process described in steps (2) to (3) for 5 times, drying with nitrogen, and then storing in a vacuum drying oven, the transformation with corrosion resistance can be obtained. coating.

Example 6

A preparation method of a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization, comprising the following steps:

(1) Polishing, cleaning and drying the magnesium-zinc-manganese alloy to be modified;

(2) The product obtained in step (1) was placed in a polydiallyldimethylammonium chloride solution with a concentration of 0.01 mM and a pH value of 7.6, reacted at 4°C for 1 min, then taken out and washed with deionized water 3 times;

(3) The product obtained in step (2) is placed in a mixed solution of epigallocatechin and polyacrylic acid with a concentration of 0.002 mM and a pH value of 7.4, reacted at 10 ° C for 5 min, then taken out, and washed with deionized water for 3 times; wherein, the mol ratio of epigallocatechin and polyacrylic acid is 1:1;

(4) Using the product obtained in step (3) as the substrate, repeating the process described in steps (2) to (3) for 5 times, drying with nitrogen, and then storing in a vacuum drying oven, the transformation with corrosion resistance can be obtained. coating.

Example 7

A preparation method of a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization, comprising the following steps:

(1) Polishing, cleaning and drying the AZ31 magnesium alloy to be modified;

(2) placing the product obtained in step (1) in a polyethyleneimine solution with a concentration of 0.02 mM and a pH value of 7.8, reacting at 4°C for 1 min, then taking out, and washing with deionized water 3 times;

(3) placing the product obtained in step (2) in a mixed solution of EGCG and heparin with a concentration of 0.001 mM and a pH of 7.2, reacting at 10° C. for 5 min, then taking it out, and washing it with deionized water 3 times; wherein, EGCG The molar ratio to heparin is 1:1;

(4) Using the product obtained in step (3) as the substrate, repeating the process described in steps (2) to (3) for 5 times, drying with nitrogen, and then storing in a vacuum drying oven, the transformation with corrosion resistance can be obtained. coating.

Example 8

A preparation method of a magnesium-based metal conversion coating with high corrosion resistance and surface functionalization, comprising the following steps:

(1) Polishing, cleaning and drying the AZ31 magnesium alloy that needs to be modified for use;

(2) placing the product obtained in step (1) in a chitosan solution with a concentration of 0.01 mM and a pH of 7.4, reacting at 4° C. for 1 min, then taking it out, and washing it with deionized water 3 times;

(3) The product obtained in step (2) was placed in a mixed solution of tannic acid and hyaluronic acid with a concentration of 0.001 mM and a pH value of 7.2, reacted at 10° C. for 5 min, then taken out and washed 3 times with deionized water ; Wherein, the molar ratio of tannic acid and hyaluronic acid is 1:1;

(4) Using the product obtained in step (3) as the substrate, repeating the process described in steps (2) to (3) for 5 times, drying with nitrogen, and then storing in a vacuum drying oven, the transformation with corrosion resistance can be obtained. coating.

detect

Atomic force microscopy (AFM) detection and anticoagulation performance detection were performed on the conversion coating prepared in Example 7, respectively, and the detection patterns are shown in Figures 1 and 2, respectively.

It can be seen from Figure 1 that the conversion coating forms a dense cross-linked network structure. Through extreme conditions and long-term immersion experiments in PBS, it is found that the coating has good resistance to extreme conditions and long-term stability.

It can be seen from Figure 2 that there is almost no platelet enrichment on the surface of the conversion coating sample, indicating that the conversion coating has good anti-platelet adhesion and anticoagulation functions; moreover, the polyphenol compounds in the conversion coating have The super-hydrophilic function can effectively prevent the aggregation of proteins in the blood on the surface of the material. In addition, the heparin molecules in the conversion coating can effectively prevent the activation and destruction of components in the blood.

A long-term immersion experiment in PBS aqueous solution was carried out to the conversion coating prepared in Example 7, and its concrete process was as follows:

First, the unmodified magnesium alloy surface was sealed with silicone rubber, and only the modified coating surface was exposed; four magnesium alloy samples with a diameter of 1 cm were put into a self-made device for measuring hydrogen, 400 ml of PBS solution was added, and the device was sealed. The amount of hydrogen released by the sample is measured every 12 hours under the condition of 37°C, the volume is read, and the rate of hydrogen release reflects the corrosion rate of the magnesium alloy; through the above detection, it is found that the hydrogen release rate is very low, indicating that the conversion coating prepared by the present invention. layer with excellent corrosion resistance.

The conversion coating and traditional coating prepared in Example 7 were respectively subjected to extreme conditions electrochemical tests, and the specific process was as follows:

The conversion coating and traditional coating prepared in Example 7 were respectively subjected to extreme conditions electrochemical tests, and the specific process was as follows:

First grind and polish the back of the sample and the copper sheet, then bond the copper sheet and the sample with conductive silver glue, seal the back of the sample with silicone rubber, and solidify overnight for the electrochemical performance test; the electrochemical test is performed at 37 °C In the PBS solution, the resistance value and the self-corrosion current of the conversion coating were detected; through the detection, it was found that the resistance value of the conversion coating prepared by the present invention was much higher than that of the traditional coating, and at the same time, the self-corrosion current also increased. It is far lower than that of the traditional coating, indicating that the conversion coating prepared by the present invention has excellent corrosion resistance.

Claims (8)

1. a kind of with highly corrosion resistant and the preparation method of surface-functionalized magnesium-base metal conversion coating, which is characterized in that The following steps are included:

(1) magnesium alloy base material is pre-processed；

(2) pretreated magnesium alloy is placed in 0.01~1mM, in the poly- positive electricity electrolyte solution that pH value is 4~10, in 4~37 DEG C reaction 1~30min after, take out simultaneously cleaned 3~5 times with deionized water；

(3) products therefrom in step (2) is placed in 0.01~20mM, the polyphenolic substance and poly- negative electricity solution that pH value is 5.5~8.5 In the mixed solution of matter, after 4~37 DEG C of 1~30min of reaction, takes out and cleaned 3~5 times with deionized water；Wherein, described more The molar ratio of phenolic compounds and poly- negative electrolyte is 1~2:1~2；

(4) using step (3) products therefrom as substrate, step (2)~(3) are repeated described process 10~100 times, and dry with nitrogen It is dry, obtain conversion coating.

2. according to claim 1 with the preparation side of highly corrosion resistant and surface-functionalized magnesium-base metal conversion coating Method, which is characterized in that magnesium alloy described in step (1) is pure magnesium, magnesium rare earth-based alloy, new bio medical magnesium alloy or magnalium It is alloy.

3. according to claim 1 with the preparation side of highly corrosion resistant and surface-functionalized magnesium-base metal conversion coating Method, which is characterized in that described in step (2) gather sun electrolyte be poly-L-Lysine hydrobromate, polyallylamine hydrochloride, Poly-L-arginine hydrochloride, polyethyleneimine, chitosan or poly- hexyl purple nitrile.

4. according to claim 1 with the preparation side of highly corrosion resistant and surface-functionalized magnesium-base metal conversion coating Method, which is characterized in that the molar ratio of polyphenolic substance described in step (3) and poly- negative electrolyte is 1:1.

5. having the preparations of highly corrosion resistant and surface-functionalized magnesium-base metal conversion coating according to claim 1 or described in 4 Method, which is characterized in that the polyphenolic substance is epicatechin, epigallocatechin, epigallocatechin galla turcica Acid esters, L-Epicatechin gallate, gallic acid, resveratrol, vitamin B2, tanshinone, chromocor compound, curcumin or Tannic acid.

6. having the preparations of highly corrosion resistant and surface-functionalized magnesium-base metal conversion coating according to claim 1 or described in 4 Method, which is characterized in that the poly- negative electrolyte is heparin, Heparan sulfate, hyaluronic acid, chondroitin sulfate, collagen egg White, glucan, keratan sulfate, polyacrylic acid, kayexalate salt, sodium alginate, polyglutamic acid or deoxyribose core Acid.

7. according to claim 1 with the preparation side of highly corrosion resistant and surface-functionalized magnesium-base metal conversion coating Method, which is characterized in that the poly- positive electrolyte concentration is 0.01~1mM, pH value 7.4；The concentration of the mixed solution is 0.001~20mM, pH value 7.2.

8. any one of claim 1~7 the method is prepared golden with highly corrosion resistant and surface-functionalized magnesium-based Belong to conversion coating.