CN117298341A

CN117298341A - Degradable hybrid coating for zinc alloy implant surface, and preparation method and application thereof

Info

Publication number: CN117298341A
Application number: CN202311230038.3A
Authority: CN
Inventors: 李小杰; 孙颖; 朱叶
Original assignee: Jiangnan University
Current assignee: Jiangnan University
Priority date: 2023-09-22
Filing date: 2023-09-22
Publication date: 2023-12-29

Abstract

The invention discloses a degradable hybrid coating on the surface of a zinc alloy implant, a preparation method and application thereof. The zinc ions are chelated by the groups on the side groups of the polycarbonate, so that the hybrid coating inhibits the release of the zinc ions and has good adhesive force. The coating effectively reduces cytotoxicity on the surface of the zinc alloy, can stably load and uniformly release magnesium ions with proper concentration, and remarkably improves the bone differentiation promoting, angiogenesis promoting and antibacterial performances of the zinc alloy implant.

Description

Degradable hybrid coating for zinc alloy implant surface, and preparation method and application thereof

Technical Field

The invention belongs to the technical field of medical materials, and particularly relates to a degradable hybrid coating on the surface of a zinc alloy implant, a preparation method and application thereof.

Background

With the increasing degree of population aging in recent years, the probability of occurrence of bone diseases and cardiovascular diseases will be significantly increased, which will inevitably lead to a great demand for bone implants and vascular intervention stents and other implant devices. The medical metal material has excellent mechanical property, fatigue resistance and easy workability, and is always the first choice material for preparing bearing implants such as bone implants, vascular stents and the like. Zinc and its alloys have several advantages as a new generation of degradable metallic bone implant materials. First, the zinc alloy material has good biocompatibility, can reduce immune response and inflammation caused by the implant, and is beneficial to improving the durability of the implant. Secondly, the zinc alloy material has excellent mechanical property and biomechanical property, the elastic modulus of the zinc alloy material is similar to that of bone tissue, and the problem of stress concentration caused by mismatching of the rigidity of the zinc alloy material can be reduced. In addition, the zinc alloy also has lower toxicity and better corrosion resistance, and is beneficial to the long-term stable operation of the implant in vivo.

However, the clinical use of zinc alloys still faces two major problems. First, zn occurs in the zinc alloy at an early stage after implantation into the body ²⁺ Is suddenly released, resulting in local Zn ²⁺ Too high a concentration of Zn in excess ²⁺ Will adhere, spread and proliferate to osteoblastsTo inhibition, severe cytotoxicity is caused; only Zn is to ²⁺ The control at a lower level (3.9-5.2 mug/mL) will only show an accelerating effect on the proliferation and differentiation of osteoblasts. Second, bone repair is a complex multi-stage process, generally involving hematoma formation, cartilage vascularization, and fibrobone formation, where both steps are critical to the bone repair process; while zinc alloy surfaces are generally considered to be a biologically inert surface, they do not meet the multiple biological functions required during bone repair. And the problem of bacterial infection caused by the surgical procedure also often results in failure of the zinc alloy implantation. Thus, zinc alloy surfaces lacking bioactivity are difficult to meet with complex bone repair procedures.

Surface coating treatments are a common method of imparting surface properties to a substrate and imparting surface functions to a substrate. In previous related studies (CN 115068699a, CN115181874 a), researchers have conducted inorganic coating studies on zinc alloy surfaces, including ZnP and carbonates, etc., to reduce the corrosion rate of zinc alloys and improve the uniformity of their surface corrosion. Although the preparation method is simpler, the preparation method is used for inhibiting Zn ²⁺ The release performance is poor, the biocompatibility of the zinc alloy surface is difficult to improve, and the requirement on the biological function diversity of the zinc alloy surface cannot be met, so that the special requirement in the orthopedic repair process is met. The polymer coating has rich types, can be designed into a coating with rich biological functions, and is widely paid attention to researchers. Researchers (CN 114246992A and CN 115177433A) have published drug-loaded coatings prepared on the surface of zinc alloy by using natural macromolecules so as to effectively improve the biocompatibility of the surface of zinc alloy and endow the surface of zinc alloy with rich biological functions. Although natural macromolecules can achieve non-toxic degradation in vivo, their inherently weak mechanical properties make it difficult to maintain coating integrity on zinc alloy surfaces for long periods of time. And the problem of bacterial infection in implantation surgery has not been widely focused on in previous studies.

Accordingly, newer materials are sought for improving zinc alloy surface coating properties.

Disclosure of Invention

The invention aims to: the invention aims to overcome the defects in the prior art, and therefore, the invention provides a preparation method and application of a degradable hybrid coating on the surface of a zinc alloy implant. The human skeleton consists of 60% inorganic component, 30% organic component and 10% water, and the organic-inorganic composite structure has strong mechanical performance and rich biological functions. We have inspired an organic-inorganic composite structure of bone, which is expected to confer biological functions to zinc alloy bone implants that match the bone repair process. Constructing a zinc alloy surface with Zn inhibition function ²⁺ Release, mg ²⁺ The degradable organic-inorganic bionic hybrid coating for controlling release, enhancing the biocompatibility and the antibacterial property of the zinc alloy surface and promoting the differentiation and the angiogenesis of osteoblasts can be provided, and the organic-inorganic composite structure can also provide better mechanical properties. Firstly, synthesizing catechol and azidobenzene functionalized amphiphilic degradable polycarbonate, mixing the solution with magnesium-containing nanoparticle dispersion liquid, obtaining magnesium-containing nanoparticle/polycarbonate mixed dispersion liquid by utilizing the adsorption stabilization effect of catechol groups on nanoparticles, preparing a degradable hybrid coating on the surface of a zinc alloy by using film forming technologies such as dip coating and the like, and finally curing the coating by using ultraviolet light. The amphiphilic degradable polycarbonate in the coating has the surface degradation characteristic of layer-by-layer degradation, and can control Mg ²⁺ Uniformly releasing, maintaining the integrity of the coating, and the catechol and azidobenzene groups which are provided after the modification endow the polymer with the functions of chelating metal ions and photocuring, so that Zn can be effectively inhibited ²⁺ And simultaneously stably adsorbs the magnesium-containing nano particles to be uniformly dispersed. By Mg ²⁺ Is uniformly released and Zn ²⁺ Inhibit release and improve biocompatibility of the zinc alloy surface. Mg of ²⁺ And Zn ²⁺ The synergistic effect of the components also promotes the proliferation and differentiation of osteoblasts and the formation of blood vessels, thereby meeting the complex bone repair process and accelerating the overall bone repair process. Meanwhile, the magnesium-containing nano particles are excellent inorganic bacteriostat, and have high-efficiency broad-spectrum antibacterial performance on various bacteria.

The aim of the invention is achieved by the following means:

a first object of the present invention is to provide a zinc alloy implant, the surface of which has a degradable hybrid coating, the degradable hybrid coating is an amphiphilic degradable polycarbonate coating loaded with magnesium-containing nanoparticles, the magnesium-containing nanoparticles include any one of magnesium oxide nanoparticles, magnesium alloy nanoparticles and magnesium silicate nanoparticles.

Alternatively, in one embodiment of the present invention, the magnesium-containing nanoparticles are 1-15% by mass of the amphipathic degradable polycarbonate.

Alternatively, in one embodiment of the present invention, the magnesium-containing nanoparticles are 1-10% by mass of the amphipathic degradable polycarbonate.

Alternatively, in one embodiment of the invention, the degradable hybrid coating has a water contact angle of less than 60 ° and an adhesion of greater than 3MPa.

Alternatively, in one embodiment of the invention, the degradable hybrid coating has a water contact angle of 50 ° -60 °, and an adhesion of 3-4MPa.

The second object of the invention is to provide a preparation method of a degradable hybrid coating on the surface of a zinc alloy implant, which comprises the following steps:

s1, carrying out ring-opening polymerization reaction on a monomer, an initiator and a catalyst I in an organic solvent I under the anhydrous and anaerobic condition to obtain degradable polycarbonate; the monomer comprises a monomer I and a monomer II, wherein the monomer I is 5-methyl-5-pentafluorophenyl carbonyl-1, 3-dioxane-2-one TMCF, and the monomer II comprises any one or more of 1, 3-dioxane-2-one TMC, lactide LA and caprolactone CL;

s2, dissolving the degradable polycarbonate in a solvent II, adding a modifier and a catalyst II for post-polymerization modification reaction to obtain the amphiphilic degradable polycarbonate, wherein the modifier comprises a modifier I and a modifier II, the modifier I is an amino small molecule containing a photosensitive group, and the modifier II is an amino small molecule with a metal ion chelating function and a stable adsorption effect on nano particles;

s3, dissolving the amphiphilic degradable polycarbonate in an organic solvent III to form a polymer solution, and adding a magnesium-containing nanoparticle dispersion liquid into the polymer solution to obtain a mixed dispersion liquid, wherein the magnesium-containing nanoparticle dispersion liquid is obtained by dispersing magnesium-containing nanoparticles in an organic solvent IV, and the magnesium-containing nanoparticles comprise any one of magnesium oxide nanoparticles, magnesium alloy nanoparticles and magnesium silicate nanoparticles;

S4, preparing the mixed dispersion liquid on the surface of the zinc alloy to form a film, drying and ultraviolet curing to obtain the degradable polycarbonate hybrid coating.

According to the invention, firstly, degradable polycarbonate is synthesized as a polycarbonate modification platform to modify various functional groups, and an azidophenyl group and a catechol group are selected in the invention, wherein the azidophenyl group belongs to a photosensitive group, and the catechol group belongs to a group with a metal ion chelating function and a stable adsorption effect on nano particles. After the degradable polycarbonate is modified by amino small molecules with catechol groups and amino small molecules with azidobenzene groups, the catechol groups of the degradable polycarbonate can be chelated with metal ions, and the degradable polycarbonate can adsorb stable nano particles, so that the degradable polycarbonate can inhibit Zn ²⁺ Simultaneous uniform release of Mg ²⁺ . Therefore, the organic-inorganic composite bionic structure coating obtained by the invention can realize the controlled release of metal ions while guaranteeing the mechanical strength of bone tissues, and make up for the application defects of zinc alloy.

Alternatively, in one embodiment of the present invention, in step S1, the molar content of the monomer I in the monomer is 10 to 40%.

Alternatively, in one embodiment of the present invention, in step S1, the reaction temperature of the ring-opening polymerization is 15 to 100 ℃ and the reaction time is 24 to 48 hours.

Alternatively, in one embodiment of the present invention, in step S1, the initiator includes any one or more of benzyl alcohol, ethanol, hydroxyl-terminated PEG, isopropyl alcohol, and propargyl alcohol.

Alternatively, in one embodiment of the present invention, in step S1, the catalyst I comprises any one or more of trifluoromethanesulfonic acid, stannous octoate, diazabicyclo DBU, 1,5, 7-triazabicyclo [4.4.0] dec-5-ene TBD, 1-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene MTBD.

Alternatively, in one embodiment of the present invention, the organic solvent I includes any one or more of dichloromethane, toluene, tetrahydrofuran, dimethyl sulfoxide, and N, N-dimethylformamide.

Alternatively, in one embodiment of the present invention, the initiator is added in an amount of 0.5 to 2% by mole of the monomer, and the catalyst I is added in an amount of 1 to 5% by mole of the monomer.

Alternatively, in one embodiment of the present invention, the initiator is added in an amount of 1% by mole of the monomer and the catalyst I is added in an amount of 2% by mole of the monomer.

Alternatively, in one embodiment of the present invention, in step S2, the amino small molecule containing a photosensitive group includes an organic compound containing an azidophenyl group.

Further alternatively, in one embodiment of the present invention, the organic compound containing an azidobenzene group includes any one or more of N- (2-aminoethyl) -4-azidobenzamide (CAS: 81416-99-1; benzamide, N- (2-aminoethyl) -4-azido- (9 CI, ACI)), N- (2-aminopropyl) -4-azidobenzamide (CAS: 851138-13-1, benzamide, N- (3-aminopropyl) -4-azido- (9 CI, ACI)).

Optionally, in an embodiment of the present invention, in step S2, the small amino molecule with a metal ion chelating function and stable adsorption to the nanoparticle includes: any one or more of catechol group-containing organic matter, 4- (2-aminoethyl) pyridine, N- (3-aminopropyl) imidazole, amino ethyl phosphonic acid and 3, 4-dihydroxyphenethylamine.

Further alternatively, in one embodiment of the present invention, the catechol group-containing organic material includes 4- (2-aminoethyl) -1, 2-benzenediol hydrochloride. Alternatively, in one embodiment of the present invention, in step S2, the total addition amount of the modifier is 1 to 1.5 times the addition amount of the monomer I, wherein the addition amount of the modifier I in the modifier is 5 to 30% by mole and the addition amount of the modifier II is 70 to 95% by mole.

Alternatively, in one embodiment of the present invention, in step S2, the post-polymerization modification reaction has a reaction temperature of 15 to 40 ℃ and a reaction time of 1.5 to 4 hours.

Alternatively, in one embodiment of the present invention, the organic solvent II includes any one or more of tetrahydrofuran, N-dimethylformamide, dichloromethane, and acetonitrile.

Alternatively, in one embodiment of the present invention, the catalyst II comprises any one or more of triethylamine TEA, triethylenediamine TEDA, 1-hydroxybenzotriazole hydrate HOBt.

Alternatively, in one embodiment of the present invention, the catalyst II is dosed in an amount of 1 to 1.5 times the molar amount of the modifier.

Alternatively, in an embodiment of the present invention, in step S3, the organic solvent III and the organic solvent iv are independently selected from any one or more of tetrahydrofuran, N-dimethylformamide, dichloromethane, acetonitrile, and acetone.

Alternatively, in one embodiment of the present invention, in step S3, the concentration of the amphiphilic degradable polycarbonate in the polymer solution is 50-200mg/mL.

Optionally, in an embodiment of the present invention, in step S3, the magnesium-containing nanoparticle includes any one of a magnesium oxide nanoparticle, a magnesium alloy nanoparticle, and a magnesium silicate nanoparticle, and in one example, the magnesium-containing nanoparticle is a magnesium oxide nanoparticle.

Optionally, in an embodiment of the present invention, in step S3, the preparation method of the dispersion solution of the magnesium-containing nanoparticles is ultrasonic dispersion, and the dispersion time is 3 hours.

Alternatively, in one embodiment of the present invention, in the step S3, the concentration of the magnesium-containing nanoparticle dispersion liquid in the magnesium-containing nanoparticle dispersion liquid is 5-30mg/mL.

Alternatively, in one embodiment of the present invention, in step S3, the content of the magnesium-containing nanoparticles in the mixed dispersion is 1 to 15% by mass of the amphiphilic degradable polycarbonate.

Alternatively, in one embodiment of the present invention, in step S3, the content of the magnesium-containing nanoparticles in the mixed dispersion is 1 to 10% by mass of the amphiphilic degradable polycarbonate.

Optionally, in one embodiment of the present invention, in step S4, the zinc alloy comprises one or more of a zinc alloy sheet, a zinc alloy cardiovascular stent, a zinc alloy bone nail, a porous zinc alloy bone implant, a zinc alloy wound fixation device;

alternatively, in one embodiment of the present invention, the film forming method includes a film forming method using one of dip coating, spin coating, knife coating, spray coating;

The ultraviolet curing wavelength is 365nm or 254nm, and the curing time is 30-300s.

Alternatively, in one embodiment of the present invention, when dip coating is used in the film forming method, the zinc alloy is immersed in the above magnesium-containing nanoparticle/polycarbonate mixed dispersion for 10 to 60 seconds; the sample was then lifted out three times slowly at 200-500 rpm. The sample was dried in an oven at 40℃for 3h vertically, and the film thickness obtained was 20-30. Mu.m.

A second object of the present invention is to provide a zinc alloy implant with a degradable hybrid coating on the surface as described above, for use in orthopedic implants, cardiovascular stents, wound fixation devices.

The beneficial effects are that: compared with the prior art, the degradable hybrid coating on the surface of the zinc alloy implant provided by the invention has the following advantages:

1) The degradable organic-inorganic hybrid coating prepared by the method has uniform thickness and good adhesive force; the magnesium-containing nano particles are uniformly dispersed on the surface and the inside of the coating, obvious agglomeration phenomenon does not occur, and the roughness and the surface elastic modulus of the coating can be regulated and controlled by controlling the content of the magnesium-containing nano particles.

2) Compared with the existing polycarbonate, the amphiphilic degradable polycarbonate prepared by the invention introduces catechol groups and azidobenzene groups into the polycarbonate at the same time, custom-made metal ion chelating function and photocuring function of the polycarbonate are given, and Zn is utilized ²⁺ The synergistic effect of the chelating function and the shielding effect of the coating can effectively inhibit Zn of zinc alloy ²⁺ And (3) the release of the zinc alloy base material is reduced.

3) Compared with the existing zinc alloy implant surface coating, the degradable organic-inorganic hybrid coating prepared by the method can realize the application of the coating in orthopedic implants, cardiovascular stents and wound fixing devices through the loading of magnesium-containing nano particles, and has universality.

4) Compared with the existing hybrid coating, the degradable hybrid coating prepared by the method has the characteristics of surface corrosion degradation, and can uniformly disperse the magnesium-containing nano particles with catechol groups with stable adsorption effect on the nano particles, so that the Mg can be controlled for a long time ²⁺ And uniformly releasing.

5) The degradable organic-inorganic hybrid coating prepared by the invention effectively improves the expression of osteoblast alkaline phosphatase and the formation of mineralized nodules, and improves the osteogenic differentiation capacity of osteoblasts; the biocompatibility of the zinc alloy surface is improved, the adhesion, proliferation and differentiation of cells are promoted, and the angiogenesis promoting performance is improved; and shows good antibacterial properties against both E.coli and Staphylococcus aureus.

Drawings

FIG. 1 is a nuclear magnetic resonance hydrogen spectrum of the amphipathic degradable polycarbonate of example 1.

FIG. 2 is a schematic representation of the preparation and performance of examples 1-3.

FIG. 3 shows total reflection of infrared light before and after UV curing of the amphipathic biodegradable polycarbonate of example 1.

Fig. 4 is a 3D picture of an atomic force microscope of examples 1-3 and comparative examples 1-2.

FIG. 5 is a load-depth curve for examples 1-3 and comparative example 2.

Fig. 6 is a scanning electron microscope picture of the surface degradable hybrid coating of the zinc alloy of example 1, example 2, example 3 and comparative example 2 and the surface of comparative example 1 and a scanning electron microscope picture thereof after soaking in a human body simulation fluid (SBF) at 37 ℃ for 30 days.

Fig. 7 shows zinc ion concentrations at various times in comparative example 1, comparative example 2 and example 3 immersed in a human body simulation Solution (SBF) at 37 ℃ for 30 days and magnesium ion concentrations at various times in example 1, example 2 and example 3 immersed in a human body simulation Solution (SBF) at 37 ℃ for 30 days.

FIG. 8 is a fluorescent staining pattern of test example 3 after 1 day and 3 days of culture using MC3T3-E1 cells in comparative example 1, comparative example 2, example 1, example 2 and example 3.

FIG. 9 is a photograph of alkaline phosphatase staining of test example 4 after 7 days of co-culturing of comparative example 1, comparative example 2, example 1, example 2 and example 3 with MC3T3-E1 cells.

FIG. 10 is a photograph of in vitro cell migration test for 0h and 12h of test example 5 showing the extract after 3 days of co-culturing of comparative example 1, comparative example 2, example 1, example 2 and example 3 with EA.hy926 cells.

FIG. 11 shows the antibacterial activity of test example 6 after 24 hours of co-cultivation of E.coli and Staphylococcus aureus with comparative example 1, comparative example 2, comparative example 3, example 1, example 2 and example 3, respectively.

Detailed Description

The invention is further illustrated below in connection with specific embodiments. It is to be understood that the present invention is not limited to the following embodiments, and the methods are regarded as conventional methods unless otherwise specified. Such materials are commercially available from public sources unless otherwise specified.

The application provides a preparation method of a degradable hybrid coating on the surface of a zinc alloy implant, which comprises the following steps:

s1, carrying out ring-opening polymerization reaction on a monomer, an initiator and a catalyst I in an organic solvent I under the anhydrous and anaerobic condition to obtain degradable polycarbonate, and precipitating in diethyl ether to purify;

s2, dissolving the degradable polycarbonate prepared in the step S1 in a solvent II, adding a modifier and a catalyst II for post-polymerization modification reaction to obtain amphiphilic degradable polycarbonate, and precipitating in diethyl ether for purification;

s3, dissolving the amphiphilic degradable polycarbonate prepared in the step S2 in an organic solvent III, and dispersing the magnesium-containing nano particles in an organic solvent IV to obtain uniform magnesium-containing nano particle dispersion; adding a magnesium-containing nanoparticle dispersion liquid into the polymer solution to obtain a mixed dispersion liquid;

s4, preparing the mixed dispersion liquid prepared in the step S3 into a film on the surface of the polished zinc alloy, drying the water and the organic solvent in the coating, and performing ultraviolet curing to obtain the degradable polycarbonate drug-loaded coating.

Specifically, the monomers in the step S1 comprise a monomer I and a monomer II, wherein the monomer I is 5-methyl-5-pentafluorophenyl carbonyl-1, 3-dioxane-2-one TMCF, and the monomer II is selected from any one or more of 1, 3-dioxane-2-one TMC, lactide LA and caprolactone CL.

Wherein, the molar content of the monomer TMCF is 10-40%, and the rest of the materials are one or more of TMC, LA, CL.

Specifically, the polymerization reaction temperature in the step S1 is 15-100 ℃, and the reaction time is 24-48 hours; the initiator is one of benzyl alcohol, ethanol, hydroxyl-terminated PEG, isopropanol and propargyl alcohol; the catalyst I is one or more of trifluoromethanesulfonic acid, stannous octoate, diazabicyclo DBU, 1,5, 7-triazabicyclo [4.4.0] dec-5-ene TBD and 1-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene MTBD; the organic solvent I is one or more of dichloromethane, toluene, tetrahydrofuran, dimethyl sulfoxide and N, N-dimethylformamide.

Specifically, the modification reaction is carried out after the polymerization in the step S2, the reaction temperature is 15-40 ℃, and the reaction time is 1.5-4 hours; the organic solvent II is one or a mixture of more of tetrahydrofuran, N-dimethylformamide, dichloromethane and acetonitrile; the total addition amount of the modifier is 1 to 1.5 times of the addition amount of the monomer I; the modifier comprises a modifier I and a modifier II, wherein the modifier I is an amino small molecule containing a photosensitive group, such as an organic matter containing an azidobenzene group; the modifier II is an amino small molecule with a metal ion chelating function; such as organic matters containing catechol groups and imidazole groups;

Wherein the modifier I is N- (2-aminoethyl) -4-azidobenzamide or N- (2-aminopropyl) -4-azidobenzamide, the addition amount of the modifier I is 5-30% of the mole amount of the monomer TMCF in the step S1, and the rest modifier II is one or more of 4- (2-aminoethyl) -1, 2-benzenediol hydrochloride, 4- (2-aminoethyl) pyridine, N- (3-aminopropyl) imidazole, aminoethylphosphonic acid and 3, 4-dihydroxyphenethylamine.

Specifically, in the post-polymerization modification reaction in the step S2, the catalyst II is one of triethylamine TEA, triethylenediamine TEDA and 1-hydroxybenzotriazole hydrate HOBt, and the feeding amount of the catalyst II is 1-1.5 times of the feeding amount of the modifier.

Specifically, the organic solvent III and the organic solvent IV in the step S3 comprise any one or more of tetrahydrofuran, N-dimethylformamide, dichloromethane, acetonitrile and acetone.

Specifically, in the S3 step, the concentration of the amphiphilic degradable polycarbonate is 50-200mg/mL; the preparation method of the magnesium-containing nanoparticle dispersion liquid comprises the steps of ultrasonic dispersion, wherein the dispersion time is 3 hours, and the concentration of the magnesium-containing nanoparticle dispersion liquid is 5-30mg/mL; the content of the magnesium-containing nano particles in the mixed dispersion liquid is 1-15% of the mass fraction of the polymer.

Specifically, the zinc alloy in the step S4 comprises one or more of a zinc alloy sheet, a zinc alloy cardiovascular bracket, a zinc alloy bone nail, a porous zinc alloy bone implant and a zinc alloy wound fixing device; the film forming method includes a film forming method using one of dip coating, spin coating, knife coating, and spray coating.

Specifically, dip-coating is adopted in the film forming method in the step S4, and zinc alloy is immersed into the magnesium-containing nanoparticle/polycarbonate mixed dispersion liquid for 10-60S; the sample was then lifted out three times slowly at 200-500 rpm. The sample was dried in an oven at 40℃for 3h vertically, and the film thickness obtained was 20-30. Mu.m. The ultraviolet curing wavelength is 365nm or 254nm, and the curing time is 30-300s.

The embodiment of the application prepares a degradable organic-inorganic hybrid coating, the introduction of catechol groups and azidobenzene groups endows zinc ion chelation and photocrosslinking capability to the polycarbonate, and the ultraviolet light-cured magnesium-containing nanoparticle/polycarbonate organic-inorganic hybrid coating is prepared on the surface of zinc alloy by utilizing the adsorption stabilization effect of the catechol groups and azidobenzene groups on nanoparticles and compositing the nanoparticle with the magnesium-containing nanoparticle. The zinc ions are chelated by the groups on the side groups of the polycarbonate, so that the hybrid coating inhibits the release of the zinc ions and has good adhesive force. The coating effectively reduces cytotoxicity on the surface of the zinc alloy, can stably load and uniformly release magnesium ions with proper concentration, and remarkably improves the bone differentiation promoting, angiogenesis promoting and antibacterial performances of the zinc alloy implant.

The embodiment of the application also provides application of the degradable hybrid coating in orthopedic implants, cardiovascular stents and wound fixing devices.

Example 1:

(1) Synthesis of degradable polycarbonate 1: benzyl alcohol is used as an initiator, DBU is used as a catalyst I, and ring-opening polymerization reaction is carried out in anhydrous dichloromethane at 25 ℃.

Specifically, the monomers TMC (3.672 g,36 mmol) and TMCF (1.304 g,4 mmol) were dried and then added to a completely dry, nitrogen-protected Schlenk flask, the flask was sealed, the reaction system was frozen with liquid nitrogen, and then the vacuum-pumping and nitrogen-introducing operations were repeated three times to ensure the evacuation of oxygen from the flask. Next, methylene chloride (8 ml), benzyl alcohol solution (0.8 ml,0.5 m) and DBU solution (1 ml,0.8 m) were sequentially injected into a Schlenk flask with magnetic stirring, polymerized for 24 hours at 25 ℃, and the solvent was removed by spin evaporation to obtain a pale yellow viscous solid, the obtained crude product was purified by precipitation twice in diethyl ether, and dried to constant weight in a vacuum oven at 40 ℃ to obtain a degradable polycarbonate 1.

(2) Synthesis of amphiphilic degradable polycarbonate 1: and (3) carrying out post-polymerization modification reaction on the prepared degradable polycarbonate 1 under the condition of taking triethylamine TEA as a catalyst.

Specifically, the prepared degradable polycarbonate 1 (1.7 g) was dissolved in anhydrous tetrahydrofuran (10 mL), and N- (2-aminoethyl) -4-azidobenzamide AEAz (81 mg,0.25 mmol), 4- (2-aminoethyl) -1, 2-benzenediol hydrochloride (901 mg,4.75 mmol) and triethylamine (834. Mu.l, 6 mmol) were added under ice-water bath. Removing the ice water bath, reacting for 2 hours at 15 ℃, adding diethyl ether, precipitating and purifying twice, and vacuum drying at 40 ℃ until the weight is constant to obtain the amphiphilic degradable polycarbonate 2.

As shown in FIG. 1, as shown in nuclear magnetic resonance hydrogen spectrogram label, characteristic peaks of hydrogen atoms on benzene rings in catechol groups appear at chemical shifts of 6.3-6.6 ppm, and characteristic peaks of hydrogen atoms of phenolic hydroxyl groups appear near chemical shifts of 8.7ppm, which indicates that the catechol groups are successfully modified; in addition, a characteristic peak of hydrogen atoms on benzene rings in the azidophenyl groups appears at a chemical shift of 8.9ppm, which proves that the azidophenyl groups are successfully modified. The successful preparation of the synthesized amphiphilic degradable polycarbonate is illustrated.

(3) Preparation of nano magnesium oxide particle/polycarbonate dispersion 1:

dissolving the prepared amphiphilic degradable polycarbonate 2 in N, N-dimethylformamide to prepare 50mg/mL polymer solution; the nano magnesium oxide particles were ultrasonically dispersed in N, N-dimethylformamide for 3 hours to prepare a nano magnesium oxide particle dispersion liquid of 5 mg/mL. Then, the nano magnesium oxide particle dispersion liquid was dropwise added to the polymer solution under magnetic stirring, wherein the nano magnesium oxide particle content was 5% by mass of the polymer, to prepare a nano magnesium oxide particle/polycarbonate dispersion liquid 1.

(4) Preparation of degradable drug-carrying coating on surface of zinc alloy implant:

the prepared nano magnesium oxide particle/polycarbonate dispersion liquid 1 is immersed into the dispersion liquid for 30s by a dip coating film forming method; the sample was then lifted out three times slowly at 200 rpm. And (3) vertically placing the sample in a 40 ℃ oven for drying for 3 hours, and carrying out crosslinking curing for 180s under 254nm UV light to obtain the degradable hybrid coating on the zinc alloy surface.

FIG. 2 shows the total reflection IR spectrum of the degradable drug-loaded coating on the surface of zinc alloy before and after UV irradiation, and the IR absorption peak of azidobenzene groups on the surface of the substrate before UV irradiation. After illumination, the characteristic infrared absorption peak of the azidobenzene group disappears, which proves that the coating is successfully photocured. The surface morphology of the coating sample is characterized by a scanning electron microscope and is shown as a figure 3, and the surface morphology of the coating is uniform and complete, and the nano magnesium oxide particles are kept uniformly dispersed, so that the phenomenon of large-area agglomeration does not occur, which is attributed to the fact that a large number of catechol groups exist in a polymer chain, and the catechol groups adsorb and stabilize the nano magnesium oxide particles through coordination so as to improve the dispersibility of the nano magnesium oxide particles.

Example 2:

(1) Synthesis of degradable polycarbonate 2: the ring-opening polymerization was carried out in anhydrous dimethyl sulfoxide at 45℃using isopropanol as initiator and trifluoromethanesulfonic acid as catalyst I.

Specifically, monomer CL (3.652 g,32 mmol) and TMCF (2.608 g,8 mmol) were dried and then added to a completely dry, nitrogen-protected Schlenk flask, the flask was sealed, the reaction system was frozen with liquid nitrogen, and then the vacuum-pumping and nitrogen-introducing operations were repeated three times to ensure the evacuation of oxygen from the flask. Next, dimethyl sulfoxide (8 ml), an isopropyl alcohol solution (0.8 ml,0.5 m) and a trifluoromethanesulfonic acid solution (1 ml,0.8 m) were sequentially injected into a Schlenk flask with magnetic stirring, polymerized at 45 ℃ for 36 hours, the solvent was removed by spin evaporation to obtain a pale yellow viscous solid, the obtained crude product was purified by precipitation twice in diethyl ether, and dried to constant weight in a vacuum oven at 40 ℃ to obtain a degradable polycarbonate 2.

(2) Synthesis of amphiphilic degradable polycarbonate 2: and (3) carrying out post-polymerization modification reaction on the prepared degradable polycarbonate 2 under the condition of taking HOBt as a catalyst.

Specifically, the prepared degradable polycarbonate 2 (1.7 g) was dissolved in anhydrous N, N-dimethylformamide (10 mL), and AEAz (640 mg,2 mmol), 4- (2-aminoethyl) -1, 2-benzenediol hydrochloride (1.517g, 10 mmol) and triethylamine (1352 g,12 mmol) were added under ice-water bath. After removing the ice water bath, reacting for 2.5 hours at 25 ℃, adding diethyl ether for precipitation and purification twice, and vacuum drying at 40 ℃ to constant weight to obtain the amphiphilic degradable polycarbonate 2.

(3) Preparation of nano magnesium oxide particle/polycarbonate dispersion 2:

dissolving the prepared amphiphilic degradable polycarbonate 2 in tetrahydrofuran to prepare 100mg/mL polymer solution; the nano magnesium oxide particles were ultrasonically dispersed in tetrahydrofuran for 3 hours to prepare a 10mg/mL nano magnesium oxide particle dispersion. Then, the nano magnesium oxide particle dispersion liquid was dropwise added to the polymer solution under magnetic stirring, wherein the nano magnesium oxide particle content was 10% by mass of the polymer, to prepare a nano magnesium oxide particle/polycarbonate dispersion liquid 2.

the prepared nano magnesium oxide particle/polycarbonate dispersion liquid 2 is immersed into the dispersion liquid for 45s by a dip coating film forming method; the sample was then lifted out slowly three times at 300 rpm. And (3) vertically placing the sample in a 40 ℃ oven for drying for 3 hours, and carrying out crosslinking curing for 240 seconds under 254nm UV light to obtain the degradable hybrid coating on the zinc alloy surface.

Example 3:

(1) Synthesis of degradable polycarbonate 3: benzyl alcohol is used as an initiator, stannous octoate is used as a catalyst I, and ring-opening polymerization reaction is carried out in anhydrous toluene at the temperature of 100 ℃.

Specifically, the monomers LA (3.266 g,24 mmol) and TMCF (5.216 g,16 mmol) were dried and then added to a completely dry, nitrogen-protected Schlenk flask, the flask was sealed, the reaction system was frozen with liquid nitrogen, and then the vacuum-pumping and nitrogen-introducing operations were repeated three times to ensure the oxygen in the flask to be discharged. Next, toluene (8 ml), benzyl alcohol solution (0.8 ml,0.5 m) and stannous octoate solution (1 ml,0.8 m) were sequentially injected into a Schlenk flask with magnetic stirring, polymerized for 48 hours at 100 ℃, the solvent was removed by spin evaporation to obtain pale yellow viscous solid, the obtained crude product was purified twice by precipitation in diethyl ether, and dried to constant weight in a vacuum oven at 40 ℃ to obtain a degradable polycarbonate 3.

(2) Synthesis of amphiphilic degradable polycarbonate 3: and (3) carrying out post-polymerization modification reaction on the prepared degradable polycarbonate 3 under the condition of taking triethylenediamine as a catalyst.

Specifically, the prepared degradable polycarbonate 3 (1.7 g) was dissolved in anhydrous methylene chloride (10 mL), and AEAz (1944 mg,6 mmol), 4- (2-aminoethyl) pyridine (2520. Mu.l, 14 mmol) and triethylenediamine (3364. Mu.g, 30 mmol) were added under the condition of ice-water bath. Removing the ice water bath, reacting for 4 hours at 40 ℃, adding diethyl ether, precipitating and purifying twice, and vacuum drying at 40 ℃ until the weight is constant to obtain the amphiphilic degradable polycarbonate 3.

(3) Preparation of nano magnesium oxide particle/polycarbonate dispersion 3:

dissolving the prepared amphiphilic degradable polycarbonate 3 in acetonitrile to prepare a polymer solution with the concentration of 150 mg/mL; the nano magnesium oxide particles were ultrasonically dispersed in acetonitrile for 3 hours to prepare a 20mg/mL nano magnesium oxide particle dispersion. Then, the nano magnesium oxide particle dispersion liquid was dropwise added to the polymer solution under magnetic stirring, wherein the nano magnesium oxide particle content was 15% by mass of the polymer, to prepare a nano magnesium oxide particle/polycarbonate dispersion liquid 3.

the prepared nano magnesium oxide particle/polycarbonate dispersion liquid 3 is immersed into the dispersion liquid for 60s by a dip coating film forming method; the sample was then lifted out slowly three times at 400 rpm. And (3) vertically placing the sample in a 40 ℃ oven for drying for 3 hours, and carrying out crosslinking curing for 300s under 365nm UV light to obtain the zinc alloy surface degradable hybrid coating.

Example 4:

the magnesium alloy nanoparticles were ultrasonically dispersed in N, N-dimethylformamide for 3 hours to prepare a 5mg/mL magnesium alloy nanoparticle dispersion, which was changed in the type of magnesium-containing nanoparticles as compared with example 1. Then, the magnesium alloy nanoparticle dispersion liquid is dropwise added into the polymer solution under magnetic stirring, wherein the content of the magnesium alloy nanoparticles is 5% of the mass fraction of the polymer, and the magnesium alloy nanoparticle/polycarbonate dispersion liquid 4 is prepared. The other steps were the same as in example 1.

Example 5:

the magnesium silicate nanoparticles were ultrasonically dispersed in N, N-dimethylformamide for 3 hours to prepare a magnesium silicate nanoparticle dispersion liquid of 5 mg/mL. Subsequently, the magnesium silicate nanoparticle dispersion liquid was dropwise added to the polymer solution under magnetic stirring, wherein the magnesium silicate nanoparticle content was 5% by mass of the polymer, to prepare a magnesium alloy nanoparticle/polycarbonate dispersion liquid 5. The other steps were the same as in example 1.

Comparative example 1:

Zn-Li alloy discs (Φ10X1mm) were successively sanded with 400#, 600#, 800#, 1000#, 1500# and 2000#, siC sandpaper. And then sequentially ultrasonic cleaning in acetone, absolute ethyl alcohol and deionized water for 20min, taking out, and naturally drying.

Comparative example 2:

in contrast to example 1, no nano-magnesia particle dispersion was added, i.e., the coating dispersion was obtained by dissolving only the amphiphilic degradable polycarbonate polymer in N, N-dimethylformamide, and the other steps were the same as in example 1.

Comparative example 3:

316L stainless steel (8X 20 mm) was sanded successively with 400# SiC sandpaper, 600# SiC sandpaper, 800# SiC sandpaper, 1000# SiC sandpaper, 1500# SiC sandpaper, and 2000# SiC sandpaper. And then sequentially ultrasonic cleaning in acetone, absolute ethyl alcohol and deionized water for 20min, taking out, and naturally drying.

Comparative example 4:

adding commercial polytrimethylene carbonate PTMC into methylene dichloride solution to prepare 50mg/mL polymer solution, and immersing zinc alloy into the dispersion for 30s by using a dip-coating film forming method; the sample was then lifted out three times slowly at 200 rpm. Drying for 24 hours at room temperature, and preparing the PTMC coating on the surface of the zinc alloy.

Test example 1:

basic properties were tested for comparative examples 1-4 and examples 1-5.

The testing method comprises the following steps: the coating cross-sectional thicknesses were observed with a scanning electron microscope for comparative examples 1-4 and examples 1-5; measuring the surface water contact angle by using an optical video contact angle analyzer; the adhesion of the coating was tested using the international standard ISO-4587-2003.

Table 1 basic performance test results of the coatings

The water contact angle of examples 1-5 and comparative example 2 was greatly reduced relative to comparative example 4, mainly due to the high amount of catechol groups contained in the amphiphilic polycarbonate, and the hydrophilicity of the coating was enhanced; the water contact angles of comparative example 2 and examples 1 to 3 gradually decrease because the polarity of the coating surface increases and the water contact angle of the hybrid coating gradually decreases as the content of the magnesium-containing nanoparticles increases. Examples 1-5 and comparative example 2 have a greatly improved adhesion strength over comparative example 4, mainly because the introduced catechol groups improve interfacial properties of the polycarbonate and zinc alloy substrate by strong chelation with zinc ions, and improve adhesion strength of the coating to the zinc alloy substrate; and the polycarbonate cured by photo-crosslinking has higher cohesive energy, which also contributes to the improvement of the coating adhesion performance; the coating of comparative example 2, examples 1-5, showed a slight decrease in adhesion strength, but still was much higher than comparative example 4, probably because the increased content of magnesium-containing nanoparticles occupied more chelating sites for catechol groups, resulting in a slight decrease in adhesion strength of the coating.

Test example 2:

the surface morphology structure and the surface roughness of the zinc alloy flakes of comparative examples 1 to 2 and examples 1 to 3 were tested.

The testing method comprises the following steps: comparative examples 1-2 and examples 1-3 were used to characterize the surface topography and surface roughness of samples using atomic force microscopy.

From the results of FIG. 4, comparative example 1 showed a crisscrossed ravines on the surface due to sanding, and comparative example 2 showed a flat surface. Whereas the surface of the MgO-added samples of examples 1-3 showed different roughness, overall, the roughness of the coating surface increased with increasing MgO content. Therefore, the degradable polycarbonate hybrid coating can regulate and control the roughness of the coating by controlling the content of the magnesium-containing nano particles, and can be regulated and controlled to the roughness of the coating which is suitable for adhesion of osteoblasts and is beneficial to adhesion of bones and implants.

Test example 3:

the elastic modulus of the coatings of the samples of comparative example 2 and examples 1-3 were tested.

The testing method comprises the following steps: comparative example 2 and examples 1-3 were studied for surface mechanical properties using a nanoindenter. The Bosch ram was selected, set to a maximum load of 3000. Mu.N, and the loading and unloading rate of 400. Mu.N/s, 5 points per sample, and the same load (3000. Mu.N) was controlled to be applied to the surface of each sample. The load-depth curves for the individual coatings are shown in fig. 5.

From the results of fig. 5, the coating layer showed a gradually decreasing elastic modulus as the MgO content was gradually increased in comparative example 2 and examples 1 to 3. Therefore, the degradable polycarbonate hybrid coating can regulate and control the elastic modulus of the coating by controlling the content of the magnesium-containing nano particles.

Test example 4:

for testing comparative example 1, comparative example 2 and example 3 to control Zn ²⁺ Release Properties and control of Mg in example 1, example 2 and example 3 ²⁺ Release properties。

The testing method comprises the following steps: the zinc alloy tablets treated with the coatings of comparative examples 1-2 and examples 1-3 were immersed in 20mL human body simulation fluid (SBF) at 37℃and 1mL of the leaching solution was withdrawn on days 1, 3, 5, 7, 10, 15, 20, 25, 30, respectively, and 1mL of fresh SBF was added. Comparison of Zn in the leaching solutions of comparative example 1, comparative example 2 and example 3 by flame atomic spectrophotometry ²⁺ The concentration was measured for Mg in the leaching solutions of example 1, example 2 and example 3 ²⁺ The concentration was measured. The results are shown in FIG. 7.

From the results of fig. 7 (a), comparative example 1, comparative example 2 and example 3 all show a tendency to rise rapidly before fluctuation stabilizes. Wherein comparative example 2 and example 3 each showed lower Zn than comparative example 1 at each time point ²⁺ Concentration, indicating that the coated sample exhibits excellent Zn inhibition ²⁺ The release properties are mainly due to the barrier effect of the coating and the catechol group versus Zn ²⁺ Is a chelate of (a) to (b); and the coating integrity remained good thanks to the surface erosion characteristics of the polycarbonate, comparative example 2 and example 3 showed excellent long-term Zn inhibition ²⁺ Release performance. Whereas example 3 suppresses Zn ²⁺ The release properties are slightly inferior to those of comparative example 2, mainly because magnesium-containing nanoparticles are degraded during the soaking process, generating a large amount of OH ^- Resulting in an increase in the pH of the leach liquor, inhibiting Zn for example 3 ²⁺ The release properties are affected. Therefore, the degradable polycarbonate hybrid coating provided by the invention has good performance of inhibiting zinc ion release.

As shown in FIG. 7 (B), at the initial stage of soaking, mg in examples 1 to 3 ²⁺ Rapid release, mg with increasing soaking time ²⁺ The release rate is gradually slow due to the surface erosion degradation characteristics of the polycarbonate coating, the integrity of the coating is maintained during soaking, mg ²⁺ And the degradation can be controlled and uniform along with the layer-by-layer degradation of the coating. Samples with high content of magnesium-containing nanoparticles exhibit more Mg ²⁺ Release, example 3 sample leach solution showed the highest Mg ²⁺ Concentration. The degradable organic-inorganic polycarbonate hybrid coating has good performanceGood Mg ²⁺ The release properties are controlled. In the comparative examples, no magnesium oxide nanoparticles were dispersed and no magnesium ions were released, so that no related test was performed.

Test example 5:

for testing the biocompatibility of the zinc alloys treated in comparative example 1, comparative example 2, examples 1-3.

The testing method comprises the following steps: the treatments of comparative example 1, comparative example 2 and examples 1 to 3 were sterilized by irradiation with ultraviolet light for 30 min. At 6.0X10 per well ⁴ Concentration of individual cells MC3T3-E1 osteoblasts were seeded onto the surface of the sample. The osteoblasts were then cultured in a medium containing 10% fetal bovine serum and 1% antibiotics (37 ℃, 5% CO) ₂ In a humid atmosphere of concentration). After 1 and 3 days of culture, cells adhered to the surface of the sample were stained with FDA staining reagent, and observed by photographing with an overhead fluorescence microscope. The results are shown in FIG. 8.

From the test results, after 1 day of cell culture, the surface active cells of comparative example 1 exhibited a round shape and had a certain number of dead cells, while the cells adhered well to and spread on the surfaces of comparative example 2 and examples 1 to 3. After 3 days of culture, dead cells on the surface of comparative example 1 increased greatly, living cells still showed a poorly adhered round shape, while dead cells were not seen on the surfaces of the samples of comparative example 2 and examples 1 to 3, and the number of well adhered cells increased, indicating that the coating effectively improved the cell compatibility on the surface of zinc alloy. This is mainly due to the coating versus Zn ²⁺ Release inhibition effect, effectively reducing Zn ²⁺ Cytotoxicity caused by excessive release, and good biocompatibility of polycarbonate provides a good biological microenvironment for adhesion, spreading and proliferation of MC3T3-E1 cells. And the content of the magnesium-containing nano particles in the coating is increased, so that the hybrid coating can continuously release Mg ²⁺ The cell type-specific antigen can be used as a signal molecule to promote proliferation of MC3T3-E1 cells and has a certain regulation effect on cell morphology; in addition, the magnesium-containing nano particles improve the roughness of the surface of the polycarbonate coating, and the surface with certain roughness has positive influence on the adhesion, spreading and proliferation of osteoblasts. However, in example 3, the content of magnesium-containing nanoparticles was high, which is intermediateThe Reactive Oxygen Species (ROS) introduced caused a small amount of cytotoxicity to MC3T3-E1 cells, resulting in a slight decrease in the proportion of living cells in example 3. Therefore, the degradable organic-inorganic polycarbonate hybrid coating can effectively improve the biocompatibility of the zinc alloy.

Test example 6:

the zinc alloys treated in comparative examples 1-2 and examples 1-3 were tested for their osteodifferentiation promoting properties.

The testing method comprises the following steps: comparative examples 1-2 and examples 1-3 were first sterilized by irradiation with ultraviolet light for 30min, and then each group of samples was separately sterilized with MC3T3-E1 osteoblasts at 37℃and 5% CO ₂ After co-culturing in a humid atmosphere at a concentration for 7 days, osteoblasts were stained with BCIP/NBT alkaline phosphatase chromogenic kit (Beyotime) and observed by photographing with an inverted light microscope.

FIG. 9 shows alkaline phosphatase staining patterns of test example 6 after 7 days of culture of comparative examples 1-2 and examples 1-3 on the surface thereof using MC3T3-E1 cells, and from the test results, comparative example 1 exhibited a small amount of dark alkaline phosphatase staining; a large amount of alkaline phosphatase staining was found in comparative example 2 and examples 1 to 3, and as the content of magnesium-containing nanoparticles was increased, the alkaline phosphatase staining was increased, significantly promoting alkaline phosphatase expression of MC3T3-E1 cells, indicating that its introduction effectively promoted osteoblast differentiation; however, with increasing content of magnesium-containing nanoparticles, the alkaline phosphatase of example 3 expressed lower than that of example 2, possibly with higher concentration of Mg ²⁺ Has an inhibiting effect on osteogenic differentiation. Therefore, the degradable organic-inorganic polycarbonate hybrid coating can effectively improve the bone differentiation promoting performance of the zinc alloy.

Test example 7:

the zinc alloys treated in comparative examples 1-2 and examples 1-3 were tested for their ability to promote angiogenesis.

The testing method comprises the following steps: first, comparative examples 1 to 2 and examples 1 to 3 were placed in a medium and immersed for 3 days to obtain an immersion medium, EA.hy926 cells were added to a 6-well plate, cultured until the confluence reached 90%, the medium was removed, a slit was made by scratching the tip of a 100L pipette tip in the middle of the well, and the detached cells were washed 3 times with PBS and then observed by photographing. 3mL of the soak medium of each group of samples was added to each well, and a blank group was set, and after 12 hours of incubation in an oven, the samples were observed by photographing with an inverted fluorescence microscope.

FIG. 10 shows photographs of EA.hy926 cells before and after 12h of culture in test example 7, comparative examples 1-2 and examples 1-3 in an in vitro cell migration experiment. Before the culture, scratches made by the 100 μm gun head are clearly visible; after 12h of incubation, ea.hy926 cells in different sample groups had migrated to different extents. The cells in comparative example 1 hardly migrate, mainly because bare zinc alloy releases a large amount of Zn ²⁺ Cell-cell communication becomes difficult due to the inability of the cells to spread and move. Comparative example 2 shows a function of promoting cell migration due to the barrier effect of the coating and catechol group versus Zn ²⁺ The coating effectively inhibits Zn ²⁺ Release of Zn to make Zn ²⁺ Released at low doses. Examples 1 to 3 Mg due to the introduction of magnesium-containing nanoparticles ²⁺ Effectively promotes the migration of EA.hy926 cells, and the promoting effect is enhanced with the increase of the content of the magnesium-containing nano particles. Therefore, the degradable organic-inorganic polycarbonate hybrid coating can inhibit Zn on the surface of the zinc alloy ²⁺ Release, effectively improving the biocompatibility of the zinc alloy bone implant, and the zinc alloy bone implant is prepared by Zn ²⁺ And Mg (magnesium) ²⁺ Exhibits excellent pro-angiogenic properties.

Test example 8:

the zinc alloys treated in comparative examples 1-3 and examples 1-3 were tested for antimicrobial properties.

The testing method comprises the following steps: using Staphylococcus aureus (gram positive, ATCC-6538) and Escherichia coli (gram negative, ATCC-700926) as bacterial models, 2mL of the mixture containing 1X 10 ⁶ The bacterial solutions of CFU/mL were incubated with comparative examples 1-3 and examples 1-3, respectively, in 10mL of 0.9% NaCl solution at 37℃for 12h, then rinsed 3 times with fresh 0.9% NaCl solution to remove non-adherent bacteria, and sonicated in 10mL of 0.9% NaCl solution for 10min to give bacterial suspensions. After dilution 1000-fold, 100. Mu.L of the bacterial suspension was spread evenly on LB agar plates, 3Culturing at 7 ℃ for 12 hours. Finally, the number of colonies on LB agar plates was counted. The bacteriostasis rate is calculated as follows:

Wherein CFU _C The colony count of the sample group of comparative example 3 is shown, and CFU indicates the colony counts of the sample groups of comparative examples 1-2 and examples 1-3.

FIG. 11 shows the antimicrobial properties of the zinc alloys treated in comparative examples 1-3 and examples 1-3 of test example 8 against E.coli and Staphylococcus aureus. The antibacterial rates of comparative example 1 on escherichia coli and staphylococcus aureus reach 86.9% and 86.6%, respectively; the antimicrobial properties of comparative example 2 were somewhat reduced due to the presence of catechol groups in the pendant polycarbonate groups, which effectively prevented Zn from the coating ²⁺ The release and antibacterial rates for E.coli and Staphylococcus aureus were 67.4% and 85.5%, respectively. Examples 1-3 have an antibacterial rate of 86.7%, 96.2% and 98.1% for E.coli, and 87.8%, 94.3% and 98.6% for Staphylococcus aureus, respectively, because the addition of the magnesium-containing nanoparticles to the coating can effectively enhance the antibacterial ability of the coating sample, and the antibacterial performance of the coating is continuously enhanced as the content of the magnesium-containing nanoparticles in the coating increases.

Due to the coating inhibiting Zn ²⁺ Release, resulting in a decrease in antimicrobial properties of the coating sample, but the magnesium-containing nanoparticles in the coating are able to react with water to form Mg (OH) ₂ Simultaneously generates electrons and holes, and the electrons are easy to be combined with O on the surface of the coating ₂ Reactive Oxygen Species (ROS) are generated by reaction, and the ROS can induce peroxidation of cell membrane lipid of bacteria, so that the cell membrane of the bacteria is damaged, and cell contents are leaked, thereby achieving the sterilization effect. In addition, positively charged nano magnesium-containing particles are attached to the surface of bacteria, so that the charge balance on the surface of cells is destroyed, and the sterilization effect of the nano magnesium-containing particles is further enhanced. Therefore, the degradable organic-inorganic polycarbonate hybrid coating provided by the invention has excellent antibacterial effect on escherichia coli and staphylococcus aureus through the synergistic effect of various antibacterial mechanisms.

The foregoing is only a preferred embodiment of the invention, it being noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present invention, and such modifications and adaptations are intended to be comprehended within the scope of the invention.

Claims

1. The zinc alloy implant is characterized in that the surface of the implant is provided with a degradable hybrid coating, the degradable hybrid coating is an amphipathic degradable polycarbonate coating loaded with magnesium-containing nano particles, and the magnesium-containing nano particles comprise any one of magnesium oxide nano particles, magnesium alloy nano particles and magnesium silicate nano particles.

2. The zinc alloy implant of claim 1, wherein the magnesium-containing nanoparticles are 1-15% by mass of the amphiphilic degradable polycarbonate.

3. The zinc alloy implant of claim 1, wherein the degradable hybrid coating has a water contact angle of less than 60 ° and an adhesion of greater than 3MPa.

4. The preparation method of the degradable hybrid coating on the surface of the zinc alloy implant is characterized by comprising the following steps:

5. The method according to claim 4, wherein in step S1, the molar content of the monomer I in the monomers is 10 to 40%;

the reaction temperature of the ring-opening polymerization reaction is 15-100 ℃ and the reaction time is 24-48h;

the initiator comprises any one or more of benzyl alcohol, ethanol, hydroxyl-terminated PEG, isopropanol and propargyl alcohol;

the catalyst I comprises any one or more of trifluoromethanesulfonic acid, stannous octoate, diazabicyclo DBU, 1,5, 7-triazabicyclo [4.4.0] dec-5-ene TBD and 1-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene MTBD;

The organic solvent I comprises any one or more of dichloromethane, toluene, tetrahydrofuran, dimethyl sulfoxide and N, N-dimethylformamide;

the addition amount of the initiator is 0.5-1.5% of the mole amount of the monomer, and the addition amount of the catalyst I is 1-5% of the mole amount of the monomer.

6. The method according to claim 4, wherein in step S2, the amino small molecule having a photosensitive group includes an organic substance having an azidophenyl group, and the amino small molecule having a metal ion chelating function and stable adsorption to nanoparticles includes: any one or more of catechol group-containing organic matter, 4- (2-aminoethyl) pyridine, N- (3-aminopropyl) imidazole, aminoethylphosphonic acid and 3, 4-dihydroxyphenethylamine;

the organic matter containing the azidobenzene group comprises any one or more of N- (2-aminoethyl) -4-azidobenzamide and N- (2-aminopropyl) -4-azidobenzamide;

the organic matter containing catechol group includes 4- (2-amino ethyl) -1, 2-benzenediol hydrochloride; the total addition amount of the modifier is 1 to 1.5 times of the addition amount of the monomer I, wherein the addition amount of the modifier I in the modifier is 5 to 30% of the molar amount, and the addition amount of the modifier II in the modifier is 70 to 95% of the molar amount.

7. The method according to claim 4, wherein in the step S2, the reaction temperature of the post-polymerization modification reaction is 15-40 ℃ and the reaction time is 1.5-4h;

the organic solvent II comprises any one or more of tetrahydrofuran, N-dimethylformamide, dichloromethane and acetonitrile;

the catalyst II comprises any one or more of triethylamine TEA, triethylenediamine TEDA and 1-hydroxybenzotriazole hydrate HOBt;

the feeding amount of the catalyst II is 1-1.5 times of the feeding amount of the modifier.

8. The method according to claim 4, wherein in the step S3, the organic solvent III and the organic solvent IV are independently selected from any one or more of tetrahydrofuran, N-dimethylformamide, dichloromethane, acetonitrile and acetone;

in the step S3, the concentration of the amphiphilic degradable polycarbonate in the polymer solution is 50-200mg/mL; the preparation method of the magnesium-containing nanoparticle dispersion liquid comprises the steps of ultrasonic dispersion, wherein the dispersion time is 3 hours, and the concentration of the magnesium-containing nanoparticle dispersion liquid is 5-30mg/mL;

the content of the magnesium-containing nano particles in the mixed dispersion liquid is 1-15% of the mass fraction of the amphiphilic degradable polycarbonate.

9. The method of claim 4, wherein in step S4, the zinc alloy comprises one or more of a zinc alloy sheet, a zinc alloy cardiovascular stent, a zinc alloy bone nail, a porous zinc alloy bone implant, a zinc alloy wound fixation device;

the film forming method comprises a film forming method selected from dip coating, spin coating, knife coating and spray coating;

the ultraviolet curing wavelength is 365nm or 254nm, and the curing time is 30-300s;

when the film forming method adopts dip coating, the zinc alloy is immersed into the magnesium-containing nanoparticle/polycarbonate mixed dispersion liquid for 10-60s; then, the sample is slowly lifted out and repeated three times at the rotating speed of 200-500 rpm; the sample was dried in an oven at 40℃for 3h vertically, and the film thickness obtained was 20-30. Mu.m.

10. Use of a zinc alloy implant according to any one of claims 1-3 in orthopedic implants, cardiovascular stents, wound fixation devices.