Preparation method of Ga / Se double ion co-modified attapulgite and multifunctional silk fibroin-based hydrogel coating with corrosion inhibition

Abstract

This invention discloses a method for preparing Ga / Se dual-ion co-modified attapulgite and a corrosion-inhibiting multifunctional silk fibroin-based hydrogel coating. The preparation process is as follows: Attapulgite is activated and surface-modified with a hydrochloric acid solution of a certain concentration; gallium nitrate solution is added and the temperature is controlled; the reaction is carried out for a period of time to obtain Ga / Se dual-ion modified attapulgite; then, it is added to a silk fibroin aqueous solution of a certain mass fraction; subsequently, (1-hydroxyethylidene) bisphosphonic acid and glycine are added, mixed evenly, and coated onto a pretreated substrate, then dried at 37°C to form a film. Compared with the prior art, the hydrogel coating prepared by this invention has good corrosion inhibition, antibacterial, and osteogenic properties, and can be widely used in the surface protection of biomedical magnesium alloys and to impart multifunctionality to them.

Description

Technical Field

[0001] This invention belongs to the field of medical device surface modification technology, specifically relating to a method for preparing a Ga / Se dual-ion co-modified attapulgite and a corrosion-inhibiting multifunctional silk fibroin-based hydrogel coating. Background Technology

[0002] The rapid degradation rate and uneven corrosion behavior of biomedical magnesium alloys have become a key bottleneck restricting their large-scale clinical application. To improve the corrosion resistance and extend the service life of magnesium alloys, the development of multifunctional protective coatings has become a research hotspot in the field of biomaterials. Among numerous corrosion protection strategies, corrosion inhibitors are considered a highly practical corrosion-resistant technology due to their ease of operation and significant effects. By loading corrosion inhibitors into the coating system, a dense protective film can be formed on the metal surface, effectively inhibiting the occurrence and development of corrosion reactions.

[0003] From the perspective of clinical application of bone repair implants, an ideal coating system needs to meet multiple functional requirements at the same time: excellent corrosion resistance, good biocompatibility, and biological activity that promotes bone integration. In recent years, hydrogels have shown broad application prospects in the field of magnesium alloy corrosion protection and multifunctional coating construction due to their unique three-dimensional network structure, tunable physicochemical properties, and excellent drug loading capacity. However, hydrogel coatings still have several inherent defects that need to be addressed: (1) Insufficient mechanical properties - low mechanical strength and poor wear resistance. They are prone to swelling, degradation, or mechanical damage in long-term immersion or complex physiological environments, resulting in failure of protective function; (2) Complex preparation process - although the construction method of hydrogel coatings is relatively simple, in order to obtain ideal comprehensive performance, it is often necessary to adopt multiple processes such as ultraviolet light polymerization and layer-by-layer self-assembly, which significantly increases the preparation complexity and technical cost.

[0004] Therefore, developing a water-based coating system that is simple to process, can efficiently load corrosion inhibitors, and has both excellent stability and biofunctionality is of great scientific significance and application value for promoting the clinical translation of biomedical magnesium alloys. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for preparing Ga / Se dual-ion co-modified attapulgite and a corrosion-inhibiting multifunctional silk fibroin-based hydrogel coating. The aim is to construct a structurally stable and functionally integrated protective coating system on the surface of magnesium alloys through a simple process route, thereby achieving multiple synergistic biological functions such as corrosion resistance, antibacterial properties, and promotion of osteoblast proliferation.

[0006] Technical solution: The present invention provides a method for preparing Ga / Se dual-ion co-modified attapulgite, comprising:

[0007] Grind the attapulgite, then place it in a hydrochloric acid solution to activate it for a period of time. Wash it with deionized water until it is neutral, centrifuge it, and dry it.

[0008] The activated attapulgite was added to a gallium nitrate solution, and the temperature was controlled. The hydrothermal reaction was carried out for a period of time. After centrifugation, it was sintered at 550℃.

[0009] The sintered attapulgite is further ground, then added to a sodium selenite solution, and the temperature is controlled for hydrothermal reaction for a period of time. After removal and drying, Ga / Se co-modified attapulgite is obtained.

[0010] Furthermore, the concentration of the hydrochloric acid solution is 1~3 mol / L.

[0011] Furthermore, the activation temperature is 50~80℃, and the treatment time is 4~24 hours.

[0012] Furthermore, the concentration of the gallium nitrate solution is 0.1~1 mol / L, and / or the concentration of the sodium selenite solution is 0.1~1 mol / L.

[0013] Furthermore, the hydrothermal reaction temperature is 70~160℃, and the reaction time is 6~24 hours.

[0014] This invention also discloses a method for preparing a corrosion-inhibiting, multifunctional silk fibroin-based hydrogel coating, comprising the following steps:

[0015] Ga / Se dual-ion co-modified attapulgite was prepared based on the above-mentioned method.

[0016] A certain ratio of silk fibroin aqueous solution and Ga / Se bis-ion modified attapulgite were mixed and mixed evenly. Then (1-hydroxyethylidene) diphosphonic acid and glycine were added to obtain a mixed solution.

[0017] Take the pretreated base metal, immerse it in the mixed solution for a period of time, take it out, and form a film at 37°C.

[0018] Furthermore, the mass fraction of silk fibroin in the aqueous solution is 5%-20%.

[0019] Furthermore, the silk fibroin solution is blended with Ga / Se dual-ion co-modified attapulgite at a mass ratio of 100:1 to 30.

[0020] Furthermore, the silk fibroin solution is blended with (1-hydroxyethylidene) bisphosphonic acid / glycine at a mass ratio of 100:1 to 10, wherein the mass ratio of (1-hydroxyethylidene) bisphosphonic acid to glycine is 1:0.1 to 1.

[0021] Furthermore, the base metal is a magnesium alloy, and its pretreatment is alkaline heat treatment, with an immersion time of 1 to 10 minutes.

[0022] Beneficial effects:

[0023] (1) The method is simple and the corrosion inhibitor used is (1-hydroxyethylidene) diphosphonic acid, which has a dual function. On the one hand, it can chemically crosslink silk fibroin to promote the formation of hydrogel and stabilize the coating structure. On the other hand, it acts as a corrosion inhibitor to inhibit the corrosion of the base metal.

[0024] (2) The coating has a variety of functions. Using Ga / Se dual-ion modified attapulgite as filler can not only improve the strength of the coating, but also give the coating antibacterial and bone growth-promoting effects through the release of Ga / Se ions.

[0025] (3) The coating material is silk fibroin, which has excellent biocompatibility and the solvent is an aqueous solution. The extraction process is green and environmentally friendly, making it suitable as a surface coating for medical devices. Attached Figure Description

[0026] Figure 1 This is a flowchart of the preparation method of the present invention.

[0027] Figure 2 The images shown are surface SEM images of Examples 1-3.

[0028] Figure 3 The polarization curves of Examples 1-5 and Comparative Examples 1-2 are for pure magnesium alloys.

[0029] Figure 4 The results of CCK-8 co-culturing MC3T3-E1 osteoblasts with pure magnesium alloy for 1 day and 2 days in Examples 1-5 and Comparative Examples 1-2 are shown.

[0030] Figure 5 Fluorescence micrographs of MC3T3-E1 osteoblasts after co-culturing with (a) pure magnesium alloy, (bc) comparative examples 1-2 and (dh) examples 1-5 for 2 days. Detailed Implementation

[0031] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0032] Example 1:

[0033] Attapulgite was ground and then pretreated with 1 mol / L hydrochloric acid at 50℃ for 4 hours. After centrifugation, the activated attapulgite was added to a 0.1 mol / L gallium nitrate solution for hydrothermal reaction at 70℃ for 6 hours. After centrifugation, it was sintered at 550℃. Then, it was added to a 0.4 mol / L sodium selenite solution for hydrothermal reaction at 70℃ for 8 hours. The sintered product was then dried to obtain Ga / Se co-modified attapulgite.

[0034] A 5% (w / w) aqueous solution of silk fibroin was prepared. Ga / Se co-modified attapulgite was added to the silk fibroin solution, with a mass ratio of silk fibroin to Ga / Se co-modified attapulgite of 100:1. After thorough mixing, (1-hydroxyethylidene) bisphosphonic acid and glycine were added, with a mass ratio of silk fibroin to (1-hydroxyethylidene) bisphosphonic acid / glycine of 100:1 and a mass ratio of (1-hydroxyethylidene) bisphosphonic acid to glycine of 1:1. Subsequently, an alkali-treated magnesium alloy was immersed in the above mixed solution for 1 minute and then removed to form a film at 37°C.

[0035] Example 2:

[0036] The basic steps are the same as in Example 1, except that:

[0037] The mass ratio of silk fibroin to Ga / Se co-modified attapulgite was 100:10, and the mass ratio of silk fibroin to (1-hydroxyethylidene) diphosphonic acid / glycine was 100:5.

[0038] Example 3:

[0039] The mass ratio of silk fibroin to Ga / Se co-modified attapulgite was 100:30, and the mass ratio of silk fibroin to (1-hydroxyethylidene) diphosphonic acid / glycine was 100:10.

[0040] Example 4:

[0041] The basic steps are the same as in Example 1, except that:

[0042] Attapulgite was pretreated with 2 mol / L hydrochloric acid at 60℃ for 12 hours. The activated attapulgite was then immersed in a 0.5 mol / L gallium nitrate solution at 120℃ for 12 hours. After sintering, it was added to a 1 mol / L sodium selenite solution at 140℃ for 16 hours.

[0043] Example 5:

[0044] The basic steps are the same as in Example 1, except that:

[0045] Attapulgite was pretreated with 3 mol / L hydrochloric acid at 75℃ for 24 hours. The activated attapulgite was then immersed in a 1 mol / L gallium nitrate solution at 140℃ for 20 hours via hydrothermal reaction. After sintering, it was added to a 2 mol / L sodium selenite solution at 160℃ for 24 hours via hydrothermal reaction.

[0046] Comparative Example 1:

[0047] The basic steps are the same as in Example 1, except that: no Ga / Se co-modified attapulgite was added in Comparative Example 1.

[0048] Comparative Example 2:

[0049] The basic steps are the same as in Example 1, except that (1-hydroxyethylidene) diphosphonic acid was not added in Comparative Example 2.

[0050] Table 1. Hardness of samples from Examples 1-5 and Comparative Examples 1-2 in this invention

[0051] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 <![CDATA[Hardness (HV 200 )]] 87.5±1.1 92.3±2.7 102.2±4.9 88.6±0.9 88.9±1.8 75.3±0.5 68.7±1.3

[0052] Table 2. Antibacterial rates of samples from Examples 1-5 and Comparative Examples 1-2 in this invention.

[0053] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Antibacterial rate (%) 83.5±3.6 90.9±7.6 95.6±8.4 89.7±2.7 94.5±3.0 41.3±5.1 75.0±4.3

[0054] Table 1 shows the micro-Vickers hardness test results of the coatings prepared in Examples 1-5 and Comparative Examples 1-2. Comparative analysis shows that the coating hardness of Example 1 is significantly improved compared to Comparative Examples 1-2, confirming that the synergistic introduction of Ga / Se co-modified attapulgite and (1-hydroxyethylidene) diphosphonic acid can effectively enhance the mechanical strength of the hydrogel coating, thereby improving its structural stability. The addition of (1-hydroxyethylidene) diphosphonic acid further improves the coating hardness. Further analysis of the data from Examples 1-3 shows that the coating hardness increases with the increase of Ga / Se co-modified attapulgite and (1-hydroxyethylidene) diphosphonic acid content, indicating that optimizing the content of functional components is beneficial for constructing a more stable coating structure. Comparison between Examples 1 and Examples 4-5 shows that, under the same attapulgite content, changing the Ga / Se loading and reaction conditions does not significantly change the coating hardness.

[0055] Table 2 shows the results of the antibacterial rate determination of the coatings prepared in Examples 1-5 and Comparative Examples 1-2 against *Escherichia coli*. Comparative analysis shows that the antibacterial performance of Example 1 is significantly enhanced compared to Comparative Example 1, indicating that Ga / Se co-modified attapulgite loading can effectively improve the antibacterial activity of the hydrogel coating. A comparison between Comparative Example 2 and Example 1 shows that after crosslinking silk fibroin with (1-hydroxyethylidene) bisphosphonic acid, it can synergistically improve the antibacterial properties of the coating with Ga / Se co-modified attapulgite. Data from Examples 1-3 show that the antibacterial rate of the coating increases in a dose-dependent manner with the increase of Ga / Se co-modified attapulgite and (1-hydroxyethylidene) bisphosphonic acid content, demonstrating good potential for regulating antibacterial performance. A comparison between Example 1 and Examples 4-5 shows that, under the same attapulgite content, increasing the Ga / Se loading on the attapulgite can improve the antibacterial properties of the coating.

[0056] Appendix Figure 2 The SEM characterization results of the surface morphology of the coatings prepared in Examples 1-3 are shown. The analysis shows that with the increase of Ga / Se co-modified attapulgite and (1-hydroxyethylidene) diphosphonic acid content in the coating system, the surface roughness of the hydrogel coating increases significantly, exhibiting a more obvious uneven morphology.

[0057] Appendix Figure 3Electrochemical polarization curves of pure magnesium alloy substrates, Examples 1-3, and Comparative Examples 1-2 in simulated body fluids are shown. Electrochemical parameter analysis shows that the pure magnesium alloy has the lowest corrosion potential and the worst corrosion resistance. Comparison of Example 1 and Comparative Example 1 shows that the addition of Ga / Se co-modified attapulgite improves corrosion resistance. Comparison of Example 1 and Comparative Example 2 shows that the addition of (1-hydroxyethylidene) diphosphonic acid improves the corrosion resistance of the coating. Further analysis of the polarization curves of Examples 1-3 shows that the effect of the three on improving the corrosion resistance of magnesium alloys gradually increases; indicating that as the content of Ga / Se co-modified attapulgite and (1-hydroxyethylidene) diphosphonic acid in the composite coating increases, the corrosion potential shows a monotonically increasing trend, demonstrating an effective protective effect on the substrate.

[0058] Appendix Figure 4 The results of CCK-8 cell viability assays for MC3T3-E1 osteoblasts after co-culturing with pure magnesium alloy, Examples 1-5, and Comparative Examples 1-2 for 1 and 2 days, respectively. Quantitative analysis showed that at both day 1 and day 2, the cell proliferation rates of the pure magnesium alloy and Comparative Examples 1-2 groups were at low levels; while the cell proliferation activity of Examples 1-3 groups increased in a dose-dependent manner, confirming that increasing the content of Ga / Se co-modified attapulgite and (1-hydroxyethylidene) bisphosphonic acid in the composite coating can effectively promote osteoblast proliferation. A comparison of Examples 1 and Examples 4-5 shows that, under the same attapulgite content, increasing the Ga / Se loading on the attapulgite can also promote cell proliferation.

[0059] Appendix Figure 5 The results are shown in the fluorescence microscopy observations of MC3T3-E1 osteoblasts co-cultured with the above samples for 2 days. (a), (b), and (c) are the fluorescence microscopy observations of pure magnesium alloy and Comparative Examples 1-2, respectively; (d), (e), (f), (g), and (h) are the fluorescence microscopy observations of Examples 1-5, respectively. The results show that the pure magnesium alloy and Comparative Examples 1-2 have fewer adherent cells and limited cell spreading area. In contrast, Examples 1-3 show a significantly increased cell adhesion density and good cell spreading morphology. Furthermore, with the increase in the content of functional components in the composite coating, both cell number and spreading area show a significant positive correlation, indicating that the composite coating is beneficial for osteoblast adhesion and spreading. A comparison of Examples 1 and Examples 4-5 shows that, under the same attapulgite content, increasing the Ga / Se loading on the attapulgite can also promote cell spreading and good growth.

[0060] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing Ga / Se dual-ion co-modified attapulgite, characterized in that, include: Grind attapulgite, place it in hydrochloric acid solution, activate it for a period of time, wash it with deionized water until neutral, centrifuge, and dry it. The activated attapulgite was added to a gallium nitrate solution, and the temperature was controlled. The hydrothermal reaction was carried out for a period of time, and then sintered after centrifugation. The sintered attapulgite is further ground, then added to a sodium selenite solution, and the temperature is controlled for hydrothermal reaction for a period of time. After removal and drying, Ga / Se co-modified attapulgite is obtained.

2. The method for preparing Ga / Se dual-ion co-modified attapulgite according to claim 1, characterized in that, The concentration of the hydrochloric acid solution is 1~3 mol / L.

3. The method for preparing Ga / Se dual-ion co-modified attapulgite according to claim 2, characterized in that, The activation temperature is 50~80℃, and the treatment time is 4~24 hours.

4. The method for preparing Ga / Se dual-ion co-modified attapulgite according to claim 1, characterized in that, The concentration of gallium nitrate solution is 0.1~1 mol / L, and / or the concentration of sodium selenite solution is 0.1~1 mol / L.

5. The method for preparing Ga / Se dual-ion co-modified attapulgite according to claim 4, characterized in that, The hydrothermal reaction temperature is 70~160℃, and the reaction time is 6~24 hours.

6. A method for preparing a corrosion-inhibiting, multifunctional silk fibroin-based hydrogel coating, characterized in that, Includes the following steps: Ga / Se dual-ion co-modified attapulgite is prepared according to any one of the preparation methods of Ga / Se dual-ion co-modified attapulgite as described in claims 1 to 5. A certain ratio of silk fibroin aqueous solution and Ga / Se bis-ion modified attapulgite were mixed and mixed evenly. Then (1-hydroxyethylidene) diphosphonic acid and glycine were added to obtain a mixed solution. Take the pretreated base metal, immerse it in the mixed solution for a period of time, take it out, and form a film at 37°C.

7. The method for preparing a corrosion-inhibiting, multifunctional silk fibroin-based hydrogel coating according to claim 6, characterized in that, The mass fraction of silk fibroin in the aqueous solution is 5%-20%.

8. The method for preparing a corrosion-inhibiting, multifunctional silk fibroin-based hydrogel coating according to claim 6, characterized in that, The silk fibroin solution was blended with Ga / Se dual-ion co-modified attapulgite at a mass ratio of 100:1 to 30.

9. The method for preparing a corrosion-inhibiting, multifunctional silk fibroin-based hydrogel coating according to claim 6, characterized in that, The silk fibroin solution is blended with (1-hydroxyethylidene) bisphosphonic acid / glycine at a mass ratio of 100:1 to 10, wherein the mass ratio of (1-hydroxyethylidene) bisphosphonic acid to glycine is 1:0.1 to 1.

10. The method for preparing a corrosion-inhibiting, multifunctional silk fibroin-based hydrogel coating according to claim 1, characterized in that, The base metal is a magnesium alloy, and its pretreatment is alkaline heat treatment, with an immersion time of 1 to 10 minutes.

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