Metal-organic framework nanomaterial, preparation therefor and use thereof

Abstract

Provided are a metal-organic framework nanomaterial, a preparation method therefor, and a use thereof, belonging to the technical field of bionanomaterials, and resolving the technical problem of inhibiting atherosclerosis using biomimetic metal-organic framework nanoenzymes. The solution is: the components of the of the metal-organic framework nanomaterial and the ratio thereof are: metal ions Ce4+ and a ligand fumaric acid in a molar ratio of 1:5. The preparation method therefor is: measuring an FA regulator and water to prepare a mixed solution, then adding fumaric acid and cerium ammonium nitrate dropwise into the mixed solution, stirring at room temperature, centrifuging, repeatedly washing alternately with water and ethanol, and finally drying overnight in a vacuum oven. A simple, efficient and convenient method for synthesizing the metal-organic framework nanomaterial is provided. The synthesized metal-organic framework nanomaterial has excellent CEH-like enzyme activity and intrinsic antioxidant activity, and can be used to increase lipid efflux and reduce lipid uptake, and decrease ox-LDL-induced foam cell formation, thereby alleviating atherosclerosis.

Description

A metal-organic framework nanomaterial, its preparation method and application

[0001] This application claims priority to Chinese Patent Application No. CN202411212516.2, filed on August 30, 2024, entitled "A Metal-Organic Framework Nanomaterial and Its Preparation Method and Application", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of bionanomaterials technology, specifically relating to a metal-organic framework nanomaterial, its preparation method, and its application. Background Technology

[0003] Atherosclerosis (AS), an inflammatory, immune, and lipid metabolic disease, is a leading cause of death and disability worldwide due to cardiovascular and cerebrovascular diseases (such as coronary heart disease, stroke, and myocardial infarction). Therefore, the treatment of AS plays a crucial role in combating cardiovascular disease. A hallmark of AS progression is the formation and accumulation of cholesterol ester-rich foam cells in the subendothelial layer of affected arteries. Foam cell formation is primarily due to an imbalance in lipid uptake, lipid processing, and reverse cholesterol transport. During the plaque stage and later progression of AS, large amounts of unesterified free cholesterol accumulate extracellularly and are primarily excreted via reverse cholesterol transport (RCT) using high-density lipoprotein (HDL) as a carrier. Since cholesterol in foam cells formed by macrophages is mainly in its bound form—cholesterol esters—to fatty acids, studies have explored the use of natural cholesterol ester hydrolases (CEHs) to improve AS. However, the complex preparation, poor stability, high cost, and low recycling rate of natural enzymes make this approach very challenging. Numerous studies have shown that damage to macrophage RCTs accelerates the progression of atherosclerosis, while enhancing macrophage RCTs can prevent or even reverse atherosclerosis. Furthermore, the efficacy of improving atherosclerosis solely through increasing lipid efflux—a single lipid downregulation mechanism—is limited because macrophages continue to uptake lipids, forming foam cells; therefore, it is necessary to simultaneously reduce lipid uptake.

[0004] Macrophages are the main source of foam cells, and oxidized low-density lipoprotein (ox-LDL), a modified low-density lipoprotein, is considered to be the main apolipoprotein accumulated during foam cell formation. Numerous studies have shown that ox-LDL levels in plaques are closely related to oxidative stress induced by high levels of reactive oxygen species (ROS). Generally, intracellular ROS-modified LDL produces ox-LDL, suggesting that reducing ROS production in plaques to inhibit ox-LDL formation may attenuate atherosclerosis. In recent years, nanoparticles with natural enzyme-mimicking catalytic activity have attracted widespread attention due to their high stability, low cost, and ease of preparation. Most importantly, nanozymes, compared to natural enzymes and traditional enzyme mimics, can rationally integrate multiple enzyme activities.

[0005] Metal-organic frameworks (MOFs) are a class of novel porous inorganic-organic hybrid materials composed of metal ions / clusters and organic ligands. Due to their diverse metal ion and ligand structures, high specific surface area, efficient drug loading, and high safety, MOF-based nanozymes have shown broad application prospects and have been widely used to scavenge free radicals and treat ROS-mediated ischemic stroke, rheumatoid arthritis, radiation damage, and other diseases. However, nanozymes with CEH-like enzyme activity have rarely been discovered; moreover, little attention has been paid to the therapeutic effects of nanozymes themselves on atherosclerosis. Therefore, it is necessary to develop new MOF materials that simultaneously possess CEH-like enzyme activity and intrinsic antioxidant activity to increase lipid efflux and reduce lipid uptake, thereby reducing ox-LDL-induced foam cell formation and alleviating atherosclerosis. Summary of the Invention

[0006] The main purpose of this application is to overcome the shortcomings of the prior art and solve the technical problem of inhibiting atherosclerosis with metal-organic framework biomimetic nanoenzymes. This application provides a metal-organic framework nanomaterial, its preparation method and application.

[0007] This application is achieved through the following technical solution:

[0008] This application provides a metal-organic framework nanomaterial, wherein the composition and proportions of the metal-organic framework nanomaterial are as follows: the metal ion is Ce. 4+ The ion, with fumaric acid as the ligand, Ce 4+ The molar ratio of ions to fumaric acid is 1:5.

[0009] In one embodiment, the size of the metal-organic framework nanomaterial is 50–200 nm.

[0010] In one embodiment, the particle size of the metal-organic framework nanomaterial is 50 nm, 100 nm, or 200 nm.

[0011] This application also provides a method for preparing the metal-organic framework nanomaterials described in the above technical solution, including the following steps:

[0012] The formic acid regulator is mixed with water to obtain a mixed solution, wherein the volume ratio of the formic acid regulator to water is (1.132~18.68):(11.32~28.868);

[0013] Fumaric acid and ceric ammonium nitrate were added to the mixed solution, stirred at room temperature for 10 min, and then centrifuged for 5 min. The solid obtained from the centrifugation was washed three times alternately with water and ethanol to obtain a solid material. The mass ratio of fumaric acid to ceric ammonium nitrate was 1.74:1.6447. The volume ratio of the mixed solution to the mass ratio of fumaric acid was 30 mL:1.74 g. The centrifugation speed was 4000 rpm.

[0014] The solid material was dried overnight in a vacuum oven to obtain the metal-organic framework nanomaterial; the drying temperature was 60°C.

[0015] This application also provides a method for preparing metal-organic framework nanomaterials, including the following steps:

[0016] S1. Measure 1.132 mL to 18.68 mL of formic acid regulator and water to prepare a 30 mL mixed solution. Mix the formic acid regulator and water thoroughly.

[0017] S2. Add 1.74g fumaric acid and 1.6447g cerium ammonium nitrate dropwise to the mixed solution prepared in step S1, stir at room temperature for 10min, then centrifuge at 4000rpm for 5min, and finally wash repeatedly with water and ethanol three times to obtain solid material.

[0018] S3. The solid material prepared in step S2 is dried overnight in a vacuum oven at 60°C to obtain metal-organic framework nanomaterials.

[0019] In one embodiment, the size of the metal-organic framework nanomaterial obtained in step S3 is 50-200 nm, and the more formic acid regulator is added in step S1, the larger the size of the metal-organic framework nanomaterial obtained.

[0020] In this application, the metal-organic framework nanomaterials possess cholesterol ester hydrolase activity and intrinsic antioxidant activity.

[0021] An application of the metal-organic framework nanomaterials described above includes:

[0022] Its application in the preparation of drugs that alleviate atherosclerosis;

[0023] Applications in the preparation of drugs that increase lipid outflow and reduce lipid upflow;

[0024] Application in the preparation of drugs that reduce macrophages and foam cells in endothelial cells;

[0025] Applications in the preparation of cholesterol ester hydrolysants or antioxidants.

[0026] In one embodiment, the foam cells are ox-LDL-induced foam cells.

[0027] The beneficial effects of this application are as follows: This application provides a simple, efficient and convenient method for synthesizing MOF nanomaterials. The synthesized MOF nanomaterials have excellent CEH enzyme-mimicking activity and intrinsic antioxidant activity, which can increase lipid efflux and reduce lipid uptake, reduce ox-LDL-induced foam cell formation, thereby alleviating atherosclerosis. Attached Figure Description

[0028] Figure 1 is a transmission electron microscope image of the MOF nanomaterials prepared in Example 1;

[0029] Figure 2 shows a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) image of the MOF nanomaterials prepared in Example 1;

[0030] Figure 3 shows the X-ray photoelectron spectroscopy (XPS) spectrum of the MOF nanomaterials prepared in Example 1;

[0031] Figure 4 shows the CEH enzyme-mimicking activity test results of the MOF nanomaterials prepared in Example 1;

[0032] Figure 5 shows the SOD activity test results of the MOF nanomaterials prepared in Example 1;

[0033] Figure 6 shows the CAT activity test results of the MOF nanomaterials prepared in Example 1;

[0034] Figure 7 shows the biosafety test results of the MOF nanomaterials prepared in Example 1;

[0035] Figure 8 shows the antioxidant properties of the MOF nanomaterials prepared in Example 1.

[0036] Figure 9 shows the test results of MOF nanomaterials prepared in Example 1 clearing excess ROS generated in cells;

[0037] Figure 10 shows a test result of the MOF nanomaterials prepared in Example 1 inhibiting foam cell formation.

[0038] Figure 11 is a transmission electron microscope image of the MOF nanomaterials prepared in Example 2;

[0039] Figure 12 is a transmission electron microscope image of the MOF nanomaterials prepared in Example 3. Detailed Implementation

[0040] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0041] Example 1

[0042] A method for preparing metal-organic framework nanomaterials includes the following steps:

[0043] S1. Measure 2.264 mL of formic acid (FA) regulator and 27.736 mL of water to prepare a 30 mL mixed solution. Mix the FA regulator and water evenly.

[0044] S2. Add 1.74 g (15 mmol) fumaric acid (FMA) and 1.6447 g (3 mmol) cerium ammonium nitrate Ce(NH4)2(NO3)6 to the mixed solution prepared in step S1, stir at room temperature for 10 min, then centrifuge at 4000 rpm for 5 min, and finally wash repeatedly with water and ethanol three times to obtain solid material.

[0045] S3. The solid material prepared in step S2 is dried overnight in a vacuum oven at 60°C to obtain metal-organic framework (MOF) nanomaterials.

[0046] The composition and ratio of the MOF nanomaterials prepared in Example 1 are as follows: the metal ion is Ce. 4+ Ions, with ligands FMA and Ce 4+ The molar ratio of ions to FMA is 1:5.

[0047] Figure 1 is a transmission electron microscope image of the MOF nanomaterials prepared in Example 1. As can be seen from Figure 1, MOF nanomaterials were successfully synthesized with a particle size of 100 nm and slight aggregation.

[0048] Figure 2 shows a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) image of the MOF nanomaterial prepared in Example 1. As can be seen from Figure 2, its main elements are Ce, C, and O.

[0049] Figure 3 shows the X-ray photoelectron spectroscopy (XPS) spectrum of the MOF nanomaterial prepared in Example 1. Ce can be obtained through peak separation calculation. 4+ The atomic percentage is 86.8%, Ce 3+ The atomic percentage is 13.2%.

[0050] The application of MOF nanomaterials in the preparation of drugs to alleviate atherosclerosis, specifically the MOF nanomaterials prepared in Example 1, are used in the preparation of drugs to alleviate apolipoprotein E deficiency (ApoE).- / - The application of MOF nanomaterials in drugs for treating atherosclerosis in mice is due to their excellent CEH enzyme-mimicking activity and intrinsic antioxidant activity. Therefore, they can be used to increase lipid efflux and reduce lipid uptake, thereby reducing foam cells (ox-LDL-induced foam cells) in macrophages and endothelial cells, as detailed below.

[0051] I. CEH Enzyme-like Activity Assay of MOF Nanomaterials

[0052] 1) Experimental principle: Cholesterol esters are first hydrolyzed by cholesterol ester hydrolase to produce free cholesterol and fatty acids. Free cholesterol is further oxidized by cholesterol oxidase to produce H2O2 and cholesterol ketone. The content of free cholesterol is determined by detecting the absorbance of the reaction product of H2O2 and fluorescent red dye (Amplex Red). Natural cholesterol ester hydrolase is used as a positive control.

[0053] 2) Prepare a cholesterol benzoate solution (50 μmol / L) and add cholesterol ester hydrolase or MOF nanomaterial solutions of different concentrations (0, 50, 100 and 200 μg / mL);

[0054] 3) Add cholesterol detection liquid, incubate at 37°C in the dark for 30 minutes, and measure the absorbance at 570nm.

[0055] II. Superoxide Dismutase (SOD) Activity Assay of MOF Nanomaterials

[0056] 1) Using xanthine (1 mM) and xanthine oxidase (0.1 U / mL) as O2· - Generation system;

[0057] 2) MOF nanomaterial solutions of different concentrations (0, 50, 100 and 200 μg / mL) were reacted with the above system at 37°C for 30 min;

[0058] 3) Detect residual O2· - The concentration of O2· - Its ability to clear debris.

[0059] III. Catalase (CAT) Activity Assay in MOF Nanomaterials

[0060] CAT activity, i.e. the hydroxyl radical scavenging ability of MOF nanomaterials, was obtained by measuring the degree of inhibition of 2-hydroxyterephthalic acid. Since terephthalic acid itself has no fluorescence, it can capture hydroxyl radicals to form 2-hydroxyterephthalic acid, which has strong fluorescence. This oxidation product is excited at 320 nm and has an emission wavelength of 425 nm. Therefore, the fluorescence spectrum at 425 nm under the excitation wavelength of 320 nm was collected.

[0061] Test procedure: 0.5 mM terephthalic acid, 10 mM H2O2 and MOF nanomaterial solutions of different concentrations (0, 50, 100 and 200 μg / mL) were mixed with 25 mM phosphate buffer solution with pH=7.4 and reacted at 37℃ for 24 h.

[0062] IV. Biocompatibility Testing of MOF Nanomaterials

[0063] 1) Human umbilical vein endothelial cells (HUVECs) were injected at a rate of 1×10⁻⁶. 4 Cells were seeded at a density of / well into 96-well plates and grown overnight at 37°C and 5% CO2 atmosphere;

[0064] 2) Remove the upper culture medium and add 100 μL of fresh culture medium containing MOF nanomaterials at concentrations of 0, 0.78, 1.56, 3.12, 6.25, 12.5, 25, 50, 100 and 200 μg / mL, respectively, and incubate together for 24 h;

[0065] 3) Add 10 μL of CCK-8 solution to each well, incubate for 2 h, and then measure the absorbance at 450 nm to calculate cell viability.

[0066] V. Antioxidant Performance Testing of MOF Nanomaterials

[0067] 1) To detect the scavenging of excess reactive oxygen species (ROS) generated intracellularly by MOF nanomaterials, HUVECs were subjected to a concentration of 4 × 10⁻⁶. 4 Cells were seeded at a density of / well into 24-well plates and grown overnight at 37°C and 5% CO2 atmosphere;

[0068] 2) Remove the upper culture medium, add culture medium containing different concentrations (0, 50, 100 and 200 μg / mL) of MOF nanomaterials and co-culture for 4 h, then add serum-free culture medium with H2O2 concentration of 60 μM to induce oxidative damage.

[0069] 3) After 20 hours, add 10 μL of CCK-8 solution to each well, incubate for 2 hours, and then measure the absorbance at 450 nm to calculate cell viability.

[0070] 4) If used for taking fluorescence images, after step 2, gently wash the cells twice with PBS to remove the old solution, add freshly prepared 2',7'-dichlorofluorescein (DCF, 10 μM) dye to each well and incubate for 2 hours, then take fluorescence images of the cells using an inverted fluorescence microscope.

[0071] VI. MOF Nanomaterials Inhibit Foam Cell Formation Test

[0072] 1) HUVEC at 2×10 4 Cells were seeded at a density of / well into 12-well plates and grown overnight at 37°C and 5% CO2 atmosphere;

[0073] 2) Remove the upper culture medium, stimulate with lipopolysaccharide (LPS, 1 μg / mL) for 24 h, and then add culture medium containing different concentrations (0, 50, 100 and 200 μg / mL) of MOF nanomaterials for co-culture.

[0074] 3) After 2 hours, incubate with 50 μg / mL ox-LDL for 48 hours. The normal control group is treated with fresh culture medium, while the model group is stimulated with ox-LDL only.

[0075] 4) After 48 hours, stain the cells with Oil Red O (ORO) staining kit and observe them with an optical microscope.

[0076] The results of the above six MOF nanomaterial performance tests are analyzed as follows:

[0077] Figure 4 shows the CEH enzyme activity test of the MOF nanomaterials prepared in Example 1. As can be seen from Figure 4, the MOF nanomaterials can effectively remove cholesterol esters in a concentration-dependent manner.

[0078] Figure 5 shows the SOD activity test diagram of the MOF nanomaterials prepared in Example 1. As can be seen from Figure 5, the MOF nanomaterials can effectively remove ROS in a concentration-dependent manner.

[0079] Figure 6 shows the CAT activity test diagram of the MOF nanomaterials prepared in Example 1. As can be seen from Figure 6, the MOF nanomaterials can effectively remove H2O2 in a concentration-dependent manner.

[0080] Figure 7 shows the biosafety test results of the MOF nanomaterials prepared in Example 1. As can be seen from Figure 7, after co-incubating the MOF nanomaterials with HUVECs cells for 24 hours, the cell survival rate was above 80%, indicating that the MOF nanomaterials have good biosafety.

[0081] Figure 8 shows the antioxidant performance test of the MOF nanomaterials prepared in Example 1. As can be seen from Figure 8, the activity of HUVECs cells decreased after H2O2 treatment. However, the addition of MOF nanomaterials can effectively resist the damage caused by H2O2 to the cells.

[0082] Figure 9 shows the test results of the MOF nanomaterials prepared in Example 1 in scavenging excess ROS generated in cells. As can be seen from Figure 9, the fluorescence intensity of HUVECs cells was highest after H2O2 treatment, indicating the generation of excess ROS. However, the fluorescence intensity of HUVECs cells significantly decreased after MOF nanomaterial treatment, indicating that cellular oxidation could be effectively inhibited. This demonstrates that MOF nanomaterials can effectively inhibit ROS generation, thereby protecting cells from oxidative stress.

[0083] Figure 10 shows a test diagram of the MOF nanomaterials prepared in Example 1 inhibiting foam cell formation. As can be seen from Figure 10, ox-LDL stimulation causes cells to produce many lipid droplets, inducing foam cell formation. However, MOF nanomaterial treatment can effectively reduce foam cell formation.

[0084] Example 2

[0085] A method for preparing metal-organic framework nanomaterials includes the following steps:

[0086] S1. Measure 1.132 mL of FA regulator and 28.868 mL of water to prepare a 30 mL mixed solution. Mix the FA regulator and water thoroughly.

[0087] S2. Add 1.74 g (15 mmol) FMA and 1.6447 g (3 mmol) Ce(NH4)2(NO3)6 to the mixed solution prepared in step S1, stir at room temperature for 10 min, then centrifuge at 4000 rpm for 5 min, and finally wash repeatedly with water and ethanol three times to obtain solid material.

[0088] S3. The solid material prepared in step S2 is dried overnight in a vacuum oven at 60°C to obtain MOF nanomaterials.

[0089] The composition and ratio of the MOF nanomaterials prepared in Example 2 are as follows: the metal ion is Ce. 4+ Ions, with ligands FMA and Ce 4+ The molar ratio of ions to FMA is 1:5.

[0090] Figure 11 is a transmission electron microscope image of the MOF nanomaterials prepared in Example 2. As can be seen from Figure 11, the particle size is 53 nm and there is slight aggregation.

[0091] The MOF nanomaterials prepared in Example 2 have the same cholesterol ester hydrolase activity and intrinsic antioxidant activity as the MOF nanomaterials prepared in Example 1. They can increase lipid efflux and reduce lipid uptake, thereby reducing foam cell formation in macrophages and endothelial cells.

[0092] Example 3

[0093] A method for preparing metal-organic framework nanomaterials includes the following steps:

[0094] S1. Measure 18.68 mL of FA regulator and 11.32 mL of water to prepare a 30 mL mixed solution. Mix the FA regulator and water thoroughly.

[0095] S2. Add 1.74 g (15 mmol) FMA and 1.6447 g (3 mmol) Ce(NH4)2(NO3)6 dropwise to the mixed solution prepared in step S1, stir at room temperature for 10 min, then centrifuge at 4000 rpm for 5 min, and finally wash repeatedly with water and ethanol three times to obtain solid material.

[0096] S3. The solid material prepared in step S2 is dried overnight in a vacuum oven at 60°C to obtain MOF nanomaterials.

[0097] The composition and ratio of the MOF nanomaterials prepared in Example 3 are as follows: the metal ion is Ce. 4+ Ions, with ligands FMA and Ce 4+ The molar ratio of ions to FMA is 1:5.

[0098] Figure 12 is a transmission electron microscope image of the MOF nanomaterials prepared in Example 3. As can be seen from Figure 12, the particle size is 200 nm and there is slight aggregation.

[0099] The MOF nanomaterials prepared in Example 3 have the same cholesterol ester hydrolase activity and intrinsic antioxidant activity as the MOF nanomaterials prepared in Examples 1 and 2. They can increase lipid efflux and reduce lipid uptake, thereby reducing foam cell formation in macrophages and endothelial cells.

[0100] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A metal-organic framework nanomaterial, characterized in that, The composition and proportions of the metal-organic framework nanomaterial are as follows: the metal ion is Ce. 4+ The ion, with fumaric acid as the ligand, Ce 4+ The molar ratio of ions to fumaric acid is 1:

5.

2. The metal-organic framework nanomaterial according to claim 1, characterized in that, The size of the metal-organic framework nanomaterial is 50–200 nm.

3. The metal-organic framework nanomaterial according to claim 2, characterized in that, The particle size of the metal-organic framework nanomaterial is 50 nm, 100 nm or 200 nm.

4. A method for preparing the metal-organic framework nanomaterial according to any one of claims 1 to 3, characterized in that, Includes the following steps: The formic acid regulator is mixed with water to obtain a mixed solution, wherein the volume ratio of the formic acid regulator to water is (1.132~18.68):(11.32~28.868); Fumaric acid and ceric ammonium nitrate were added to the mixed solution, stirred at room temperature for 10 min, and then centrifuged for 5 min. The solid obtained from the centrifugation was washed three times alternately with water and ethanol to obtain a solid material. The mass ratio of fumaric acid to ceric ammonium nitrate was 1.74:1.6447. The volume ratio of the mixed solution to the mass ratio of fumaric acid was 30 mL:1.74 g. The centrifugation speed was 4000 rpm. The solid material was dried overnight in a vacuum oven to obtain the metal-organic framework nanomaterial; the drying temperature was 60°C.

5. A method for preparing the metal-organic framework nanomaterial according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Measure 1.132 to 18.68 mL of formic acid regulator and water to prepare a 30 mL mixed solution. Mix the formic acid regulator and water thoroughly. S2. Add 1.74g fumaric acid and 1.6447g cerium ammonium nitrate to the mixed solution prepared in step S1, stir at room temperature for 10min, then centrifuge at 4000rpm for 5min, and finally wash repeatedly with water and ethanol three times to obtain solid material. S3. The solid material prepared in step S2 is dried overnight in a vacuum oven at 60°C to obtain metal-organic framework nanomaterials.

6. The method for preparing metal-organic framework nanomaterials according to claim 5, characterized in that, The method of adding 1.74g of fumaric acid and 1.6447g of cerium ammonium nitrate includes dropwise addition.

7. The method for preparing metal-organic framework nanomaterials according to claim 5, characterized in that, The metal-organic framework nanomaterials prepared in step S3 have a size of 50–200 nm.

8. An application of the metal-organic framework nanomaterial according to any one of claims 1 to 3, characterized in that, The application is in the preparation of drugs that alleviate atherosclerosis.

9. An application of the metal-organic framework nanomaterial according to any one of claims 1 to 3, characterized in that, The application is in the preparation of drugs that increase lipid outflow and reduce lipid upflow.

10. An application of the metal-organic framework nanomaterial according to any one of claims 1 to 3, characterized in that, The application is in the preparation of drugs that reduce macrophages and foam cell formation in endothelial cells.

11. The application according to claim 10, characterized in that, The foam cells are ox-LDL-induced foam cells.

12. An application of the metal-organic framework nanomaterial according to any one of claims 1 to 3, characterized in that, The application is in the preparation of cholesterol ester hydrolysants or antioxidants.

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