An enzyme-responsive silica nanoformulation, preparation method and application

Abstract

The present invention belongs to the technical field of pharmaceutical preparation application, and provides an enzyme-responsive silica nanoformulation, a preparation method and an application. The present invention intends to use simvastatin as a model drug, and then polyethyleneimine and hyaluronic acid are modified layer by layer on the outer surface of mesoporous silica nanoparticles to form an enzyme-responsive silica nanoformulation. The preparation steps are as follows: 1) synthesizing mesoporous silica nanoparticles under alkaline conditions; 2) loading simvastatin into the pores of the nanoparticles; 3) respectively coating polyethyleneimine and hyaluronic acid layer by layer on the outer surface of the mesoporous silica nanoparticles, and finally obtaining an enzyme-responsive silica nanoformulation. An enzyme-responsive silica nanoformulation of the present invention has the characteristics of uniform particle size, good dispersibility, high drug loading and low toxicity, and can trigger the enzyme response characteristics to release drugs in a high-concentration enzyme environment at the lesion site to improve its anti-atherosclerotic effect.

Description

Technical Field

[0001] The present invention relates to the technical field of pharmaceutical preparations, and in particular to an enzyme-responsive silica nano-preparation, a preparation method and an application thereof. Background Art

[0002] Atherosclerosis is one of the main causes of cardiovascular disease. Atherosclerosis is a chronic inflammatory disease characterized by lipid retention in the walls of medium and large arteries and the formation of plaques by monocyte infiltration. As the disease progresses, it can eventually lead to fatal events such as myocardial infarction and ischemic stroke. Traditional drug treatments, including lipid-lowering drugs (such as statins and fibrates), platelet aggregation inhibitors, antihypertensive drugs, and antidiabetic drugs (such as thiazolidinediones), usually have low efficacy and serious side effects. Therefore, it is necessary to develop new drug carriers to accurately treat atherosclerosis. Therefore, various functionalized organic or inorganic nanoparticles are used to combat atherosclerosis.

[0003] Mesoporous silica nanoparticles (MSNs) have attracted extensive attention due to their highly ordered pores, large surface area, high pore volume, multiple surface functions, and good biocompatibility. They can achieve high loading of therapeutic drugs on the internal or external surface while releasing the drugs in a controlled manner. In addition, the release of drugs can be further manipulated by modifying the stimulus-responsive "switch", which can be removed under specific environmental stimuli to release the sealed drug. In addition, the particle surface can be coupled with a variety of targeting ligands to achieve precise drug delivery to target cells.

[0004] A large amount of hyaluronidase (HAase) exists in atherosclerotic plaques and macrophages, which can trigger the enzyme response characteristics of hyaluronic acid (HA)-modified nanoformulations, thereby accelerating the leakage of drugs from the pores; in addition, a large number of CD44 receptors on the surface of macrophages can specifically bind to hyaluronic acid-modified nanoformulations, enter macrophages through endocytosis and release drugs. A layer of polyethyleneimine (PEI) is modified on the surface of nanoparticles through electrostatic adsorption to provide a large number of amino groups for the chemical modification of hyaluronic acid. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an enzyme-responsive silica nanoformulation, which has the characteristics of high drug loading, low toxicity, macrophage targeting and enzyme-responsive drug release in plaque sites. The enzyme-responsive silica nanoformulation is prepared by loading simvastatin into mesoporous silica nanoparticles, and then modifying the outer surface of the mesoporous silica nanoparticles with polyethyleneimine and hyaluronic acid layer by layer. The hydrated particle size of the prepared nanoparticles is 100 to 220 nm.

[0006] The second object of the present invention is to provide a method for preparing an enzyme-responsive silica nanoformulation, comprising the following steps:

[0007] 1) preparing mesoporous silica nanoparticles in an alkaline environment, and obtaining mesoporous silica nanoparticle powder after drying and calcining;

[0008] 2) dissolving mesoporous silica nanoparticles and simvastatin in a solvent, collecting a sample after the reaction is complete, and obtaining mesoporous silica nanoparticles encapsulating simvastatin;

[0009] 3) adding polyethyleneimine to the mesoporous silica nanoparticles encapsulating simvastatin obtained in 2), collecting a sample after the reaction is complete, and obtaining polyethyleneimine-modified mesoporous silica nanoparticles encapsulating simvastatin;

[0010] 4) adding the activated sodium hyaluronate to the polyethyleneimine-modified mesoporous silica nanoparticles loaded with simvastatin obtained in 3) to react, collecting the sample after the reaction is complete, and finally obtaining an enzyme-responsive silica nanoformulation;

[0011] Preferably, the anti-atherosclerotic drug in 2) is simvastatin.

[0012] Preferably, the solvent in 2) is dichloromethane.

[0013] Preferably, the mass ratio of the mesoporous silica nanoparticles to simvastatin in 2) is 2:1-2; and the concentration of simvastatin in the solvent is 15-30 mg / ml.

[0014] Preferably, the concentration of polyethyleneimine in the solution in 3) is 2 mg / ml.

[0015] Preferably, in 3), the solvent is a PBS buffer solution with a pH of 7.4; in 4), the solvent is ultrapure water.

[0016] Preferably, the activator in 4) is an amide condensation agent, and the amide condensation agent is EDC / NHS. Preferably, in 1), hexadecyl ammonium bromide and sodium hydroxide are dissolved in ultrapure water, stirred and heated to 80°C, and after the solution is completely clarified, anhydrous ethanol is added, stirred for 5 minutes, and then the ethyl orthosilicate solution is slowly dripped, reacted at 80°C for 2 hours, centrifuged, washed with distilled water 3 times, washed with methanol once, and then the product is transferred to an evaporating dish, dried in a constant temperature oven overnight, and after the product is completely dried, transferred to a muffle furnace, calcined at 550°C for 5 hours, and finally a white powder is obtained. The product is recorded as mesoporous silica nanoparticles MSN;

[0017] 2), 30 mg MSN and 15 mg simvastatin SIM were mixed in 2 ml dichloromethane, ultrasonicated for 10 min to make them dispersed evenly, and then stirred at room temperature for 24 hours. Next, the supernatant was removed by centrifugation, and the remaining solid was dried in a vacuum oven at room temperature for 24 hours. The product was recorded as simvastatin-loaded mesoporous silica nanoparticles SIM@MSN;

[0018] 3) SIM@MSN was weighed and dispersed in PBS. 100 μl of PEI solution was slowly added to the nano solution at 500 rpm and stirred at room temperature for 30 min. The product was then centrifuged, washed with water for 3 times, and stored at 4°C. This was recorded as simvastatin-loaded polyethyleneimine-coated mesoporous silica nanoparticles SIM@PEI-MSN.

[0019] 4), HA, NHS and EDC were dissolved in ultrapure water and stirred for 1 h to activate the carboxyl groups, and then SIM@PEI-MSN was added. After ultrasonic dispersion for 10 min, stirring was continued for 24 h. The product was then centrifuged, washed with water three times, and freeze-dried overnight. The product was recorded as an enzyme-responsive silica-release nanoformulation SIM@HA-MSN.

[0020] In the technical solution of the present invention, the amide condensation agent in step 4) is selected from EDC / NHS.

[0021] The polyethyleneimine used in the present invention is a commercially available product, and its molecular weight is preferably 10 kDa; the sodium hyaluronate used in the present invention is a commercially available product, and its molecular weight is preferably 330 kDa.

[0022] The third object of the present invention is to provide an application of an enzyme-responsive silica nanoformulation, which is used in the treatment of atherosclerosis.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The preparation method of the enzyme-responsive silica nanoformulation of the present invention is simple, low-cost and pollution-free; the nanoparticles have uniform particle size, good dispersibility, and are characterized by high drug loading, high biocompatibility and low toxicity. The preparation method can specifically target the CD44 receptor on the surface of macrophages while improving the bioavailability of simvastatin, and trigger the enzyme response characteristics to release drugs in a high-concentration enzyme environment at the lesion site to improve its anti-atherosclerotic effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The process flow chart of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0026] Figure 2A transmission electron microscope image of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0027] Figure 3 This is a hydrated particle size diagram of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0028] Figure 4 The Zeta potential diagram of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0029] Figure 5 is a nitrogen adsorption / desorption curve of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0030] Figure 6 The in vitro drug release curve of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0031] Figure 7 This is a diagram showing the cytotoxicity evaluation results of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0032] Figure 8 This is a graph showing the blood compatibility evaluation results of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0033] Fig. 9 This is a diagram showing the evaluation results of cellular uptake of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0034] Fig.10 This is a graph showing the in vitro anti-inflammatory evaluation results of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention;

[0035] Fig.11 This is a diagram showing the anti-macrophage foaming evaluation results of an enzyme-responsive mesoporous silica nanoformulation prepared in the present invention. DETAILED DESCRIPTION

[0036] In order to make the technical solution of the present invention easier to understand, the technical solution of the present invention is clearly and completely described in the form of specific embodiments in combination with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0037] Example 1

[0038] A method for preparing an enzyme-responsive silica nanoformulation comprises the following steps:

[0039] 1) Dissolve 0.4g of hexadecyl ammonium bromide and 1.44ml of 2M sodium hydroxide in 200ml of ultrapure water, stir and heat to 80°C. After the solution is completely clarified, add 0.4ml of anhydrous ethanol, stir for 5min, then slowly drip 2ml of ethyl orthosilicate solution, and react at 80°C for 2h. After centrifugation (10200rpm, 15 minutes), wash with distilled water 3 times and methanol once. Then transfer the product to an evaporating dish and dry it in a constant temperature oven overnight. After the product is completely dried, transfer it to a muffle furnace and calcine it at 550°C for 5h to finally obtain a white powder, which is recorded as mesoporous silica nanoparticles MSN.

[0040] 2) 30 mg MSN and 15 mg simvastatin SIM were mixed in 2 ml dichloromethane, ultrasonicated for 10 min to make them dispersed evenly, and then stirred at room temperature for 24 hours. Next, the supernatant was removed by centrifugation, and the remaining solid was dried in a vacuum oven at room temperature for 24 hours. The product was recorded as simvastatin-loaded mesoporous silica nanoparticles SIM@MSN.

[0041] 3) Weigh 30 mg of SIM@MSN and disperse it in 4 ml of PBS. Slowly add 100 μl of PEI solution (75 mg / ml) to the nano solution at 500 rpm and stir at room temperature for 30 min. Then centrifuge the product, wash it with water three times, and store it at 4 degrees. This is recorded as simvastatin-loaded polyethyleneimine-coated mesoporous silica nanoparticles SIM@PEI-MSN.

[0042] 4) 15 mg HA, 40 mg NHS and 30 mg EDC were dissolved in 10 ml ultrapure water and stirred for 1 h to activate the carboxyl groups, then 30 mg SIM@PEI-MSN was added, ultrasonically dispersed for 10 min and stirred for 24 h, then the product was centrifuged, washed with water 3 times, and freeze-dried overnight. The product was recorded as an enzyme-responsive silica nanoformulation SIM@HA-MSN. Please also refer to the process flow chart of enzyme-responsive mesoporous silica nanoformulation Figure 1 .

[0043] like Figure 2 As shown in FIG. 1 , a transmission electron micrograph of an enzyme-responsive silica nanoparticle prepared in the present invention is shown. It can be seen that the nanoparticles are elliptical in shape, and the two-dimensional pores distributed on the surface are difficult to distinguish due to the modification of the polymer. Figure 3 The hydrated particle size result shown is 189.1 ± 5.8 nm.

[0044] like Figure 4As shown, the Zeta potentials of MSN, SIM@PEI-MSN and SIM@HA-MSN prepared in Example 1 are -25.1±2.8 mV, +30.1±3.0 mV and -22.6±3.4 mV, respectively. The absolute values ​​of the surface charges of the three are relatively high, and the repulsion between the particles is relatively strong, so they can be stably dispersed in the solution.

[0045] like Figure 5 As shown, the nitrogen adsorption-desorption curve and pore size distribution diagram show that compared with MSN, the BET specific surface area, pore volume and pore size of SIM@HA-MSN are significantly reduced, indicating that the nano surface has been successfully modified.

[0046] Example 2

[0047] A method for determining drug loading and encapsulation efficiency of mesoporous silica nanoparticles comprises the following steps:

[0048] The drug loading and encapsulation efficiency of simvastatin-loaded mesoporous silica nanoparticles SIM@MSN were determined by ultraviolet spectrophotometry. 30 mg MSN and 15 mg SIM were accurately weighed and mixed in 2 ml dichloromethane, ultrasonicated for 10 min to make them dispersed evenly, and then stirred at room temperature for 24 hours. The supernatant was collected by centrifugation, filtered through a 0.22 μm filter membrane, and then the simvastatin content was measured by ultraviolet spectrophotometry, and the detection wavelength was set to 238 nm.

[0049] The calculation is performed according to the equation listed below:

[0050] Drug loading = (drug content in nanoparticles) / (total amount of nanoparticles) × 100%

[0051] Encapsulation efficiency = (actual drug loading) / (initial dosage) × 100%

[0052] Table 1 shows the drug loading and encapsulation efficiency of simvastatin-loaded mesoporous silica nanoparticles SIM@MSN prepared in Example 1.

[0053] Table 1:

[0054] Drug loading (%) Encapsulation rate (%) 21.32±1.31 55.21±2.23

[0055] As can be seen from Table 1, the simvastatin-loaded mesoporous silica nanoparticles SIM@MSN prepared in Example 1 have a higher drug loading capacity and encapsulation efficiency.

[0056] Example 3

[0057] A study on the in vitro enzyme-responsive release of an enzyme-responsive silica nanoformulation SIM@HA-MSN comprises the following steps:

[0058] Briefly, a certain amount of nanoparticles was evenly dispersed in 40 mL PBS (10 mM, containing 0.2% SDS, pH = 7.4). In order to study the responsiveness of the enzyme, hyaluronidase was added to the medium. All samples were shaken at 100 rpm at 37 ° C. At the specified time interval, the sample was centrifuged, 2 ml of buffer was collected, and the same volume of fresh buffer was replaced. The SIM release amount was determined by high performance liquid chromatography (HPLC, Agilent 1200 series) at a wavelength of 238 nm using an Agilent C18 column (4.6 mm × 250 mm, 5 μm). The mobile phase was acetonitrile: 0.025 M sodium dihydrogen phosphate solution (76:24 V: V), the flow rate was 1.0 mL / min, and the injection volume was 20 μL.

[0059] like Figure 6 As shown, the in vitro release results of simvastatin in Example 3. The sustained release of SIM@MSN within 48h was 70.11±4.64%, while the sustained release of SIM@HA-MSN was 28.02±4.11%, indicating that the HA coating can effectively prevent the release of SIM. In order to simulate the plaque environment with high levels of hyaluronidase (HAase) expression, HAase (100U / mL) was added to the buffer. Compared with the low drug release of blank PBS, the drug release rate of SIM@HA-MSN within 48h was 62.24±5.82%, because the HA layer ruptured rapidly after HAase degradation. In general, these results indicate that the HA modification on SIM@HA-MSN can act as a "gatekeeper" to effectively block drug leakage from normal tissues, and has an in vitro sustained release effect compared to SIM@MSN.

[0060] Example 4

[0061] A study on the cytotoxicity of an enzyme-responsive silica nanoformulation comprises the following steps:

[0062] like Figure 7 The results of the cytotoxicity of nanoparticles to mouse macrophage Raw264.7 cells and human umbilical vein epithelial cells HUVEC cells are shown. The cytotoxicity of nanoparticles to cells was determined using Alamar Blue reagent. The specific steps are as follows: Raw264.7 cells and HUVEC cells were inoculated into 96-well plates, with a density of 5×10 3 The cells were maintained at 37°C and 5% CO 2Cultured overnight in an incubator. Different concentrations (0, 10, 50, 200, 400 μg / mL) of SIM@HA-MSN were added to a 96-well plate as the experimental group and blank culture medium as the control group. After 24 hours, the culture medium was discarded, and 100 μL of Lamar blue reagent was added to each well and incubated for another 4 hours. Then, the microplate reader (SpectraMax ID5, bio-strategy) was used for analysis, and the wavelength was set to 570 nm and 600 nm. Calculate and report the cell viability percentages of the experimental group and the control group.

[0063] The results of cytotoxicity experiments showed that after incubating cells with SIM@HA-MSN at a concentration of 20-400 μg / mL for 24 hours, the survival rates of Raw264.7 cells and HUVECs were both higher than 80%, indicating that the particles have good cell compatibility. The decrease in cell viability caused by high-dose SIM@HA-MSN may be due to the fact that the released SIM can inhibit the proliferation of macrophages and inhibit plaque inflammatory response.

[0064] Example 5

[0065] A study on the blood compatibility of an enzyme-responsive silica nanoparticle preparation comprises the following steps:

[0066] like Figure 8 The blood compatibility of the nanoparticles was evaluated as shown. Since damage to red blood cells can induce the release of hemoglobin, the hemolysis rate was determined by measuring the absorbance of hemoglobin in the supernatant at a wavelength of 576 nm. The hemolysis rate of MSN was dose-dependent, and the hemolysis rate was as high as 46.24±3.92% at 800μg / mL, and red blood cells were significantly hemolyzed. In contrast, the hemolysis rate of SIM@HA-MSN (<5%) was negligible. This result indicates that SIM@HA-MSN has better blood compatibility than naked MSN due to the shielding effect of HA.

[0067] Example 6

[0068] A study on the cellular uptake of an enzyme-responsive silica nanoformulation comprises the following steps:

[0069] like Fig. 9 Raw264.7 cells were cultured at 5 × 10 4 The cells were seeded at a density of 100 μg / well in a 24-well plate and incubated at 37 °C and 5% CO 2Cultured overnight in an incubator. 100 ng / mL LPS was added to each well and incubated for 24 h. After washing with PBS, FITC-modified HA-MSN (FITC-HA-MSN) and MSN (FITC-MSN) were co-incubated with Raw264.7 cells for 2 h, respectively, with a final concentration of 50 μg / mL in each group. After washing with PBS, each well was fixed with 100 μL 4% PFA solution for 10 min and DAPI stained for 10 min. Finally, the cells were observed under a confocal laser scanning microscope (CLSM, Leica Stellaris). In the competitive inhibition experiment, the blank culture medium was replaced with HA-containing culture medium (10 mg / mL), and FITC-labeled HA-MSN (50 mg / mL) was co-cultured with Raw264.7 cells, and the treatment method was the same as above.

[0070] Cells treated with FITC-MSN showed weak green fluorescence. In contrast, the FITC-HA-MSN group captured significant green fluorescence. It is worth noting that before FITC-HA-MSN treatment, Raw264.7 cells were treated with 10 mg / mL of free HA, which showed very weak green fluorescence because free HA blocked the CD44 receptor on macrophages, thereby hindering the recognition and internalization of HA-MSN by cells. Therefore, the above data indicate that HA can target inflammatory macrophages through CD44-mediated internalization.

[0071] Example 7

[0072] A study on the effect of an enzyme-responsive silica nanoformulation on the level of macrophage inflammatory factors includes the following steps:

[0073] like Fig.10 The effect of SIM@HA-MSN on typical inflammatory factors secreted by Raw264.7 cells is shown in Figure 2. 5 The cells were seeded into 24-well plates at a density of 100 mL / mL and incubated at 37°C in 5% CO 2Incubate overnight in an incubator. The positive control group was treated with 100 ng / mL LPS for 24 h, and the remaining groups were treated with equivalent amounts of LPS and equivalent free SIM, SIM@MSN or SIM@HA-MSN for 24 h. ELISA kits were used to detect TNF-α and IL-6 protein concentrations. Compared with the control group stimulated with LPS alone, TNF-α and IL-6 levels were significantly reduced after treatment with SIM, SIM@MSN and SIM@HA-MSN. It is worth noting that the lowest levels of TNF-α and IL-6 in the SIM@HA-MSN group were 514.12 and 273.62 pg / mL, respectively. The results show that SIM@HA-MSN has a strong anti-inflammatory effect on inflammatory macrophages.

[0074] Example 8

[0075] A study on the effect of an enzyme-responsive silica nanoformulation on macrophage foaming comprises the following steps:

[0076] like Fig.11 The inhibitory effect of SIM@HA-MSN on foam cells induced by Raw264.7 cells is shown. 4 The cells were seeded in 24-well plates at a density of 1:1 / well and incubated at 37°C in 5% CO. 2 The cells were incubated overnight in an incubator. The positive control group was treated with 100 ng / mL LPS for 24 h, and the remaining groups were treated with equal amounts of LPS and equivalent amounts of free SIM, SIM@MSN, or SIM@HA-MSN for 24 h. Subsequently, the macrophages attached to each group were washed three times with PBS, fixed with 4% PFA for 10 min, and stained with freshly filtered 0.3% Oil Red O for 15 min. Finally, they were placed in 60% isopropanol for 5 min and imaged using an optical microscope. We evaluated the inhibitory effect of SIM@HA-MSN on oxLDL-induced foamy macrophage formation. After treatment with SIM, SIM@MSN, and SIM@HA-MSN, the Oil Red staining area was significantly reduced. Among them, SIM@HA-MSN had the most significant inhibitory effect, with a staining area of ​​only 6.77 ± 0.85%. These results confirm the effective inhibitory effect of SIM@HA-MSN on macrophage foam, which may help to clear foam cells in plaques.

[0077] Through the above-mentioned Examples 3 to 8, it can be proved that the enzyme-responsive silica nanoformulation has a good therapeutic effect on atherosclerosis.

[0078] It should be noted that the embodiments described herein are only partial embodiments of the present invention, rather than all implementations of the present invention, and the embodiments are only exemplary, and their role is only to provide a more intuitive and clear way to understand the content of the present invention, rather than to limit the technical solutions described in the present invention. Without departing from the concept of the present invention, all other implementation methods that can be thought of by ordinary technicians in this field without creative work, and other simple replacements and various changes to the technical solutions of the present invention, all belong to the protection scope of the present invention.

Claims

1. A silica nanoparticle preparation having enzyme responsiveness, characterized in that: The enzyme-responsive silica nanoformulation is formed by loading simvastatin into mesoporous silica nanoparticles, and then modifying the outer surface of the mesoporous silica nanoparticles with polyethyleneimine and hyaluronic acid layer by layer, and the hydrated particle size of the prepared nanoparticles is 100 to 220 nm; The preparation method of the enzyme-responsive silica nanoformulation comprises the following steps: 1) preparing mesoporous silica nanoparticles in an alkaline environment, and obtaining mesoporous silica nanoparticle powder after drying and calcining; 2) dissolving mesoporous silica nanoparticles and simvastatin in a solvent, collecting a sample after the reaction is complete, and obtaining mesoporous silica nanoparticles encapsulating simvastatin; 3) adding polyethyleneimine to the mesoporous silica nanoparticles encapsulating simvastatin obtained in 2), collecting a sample after the reaction is complete, and obtaining polyethyleneimine-modified mesoporous silica nanoparticles encapsulating simvastatin; 4) adding the activated sodium hyaluronate to the polyethyleneimine-modified mesoporous silica nanoparticles loaded with simvastatin obtained in 3) to react, collecting the sample after the reaction is complete, and finally obtaining an enzyme-responsive silica nanoformulation; 1), dissolving hexadecyl ammonium bromide and sodium hydroxide in ultrapure water, stirring and heating to 80°C, adding anhydrous ethanol after the solution is completely clarified, stirring for 5 minutes, and then slowly dropping ethyl orthosilicate solution, reacting at 80°C for 2 hours, centrifuging, washing with distilled water 3 times, washing with methanol once, and then transferring the product to an evaporating dish, drying in a constant temperature oven overnight, and transferring the product to a muffle furnace after it is completely dried, calcining at 550°C for 5 hours, and finally obtaining a white powder, which is recorded as mesoporous silica nanoparticles MSN; 2), MSN and simvastatin SIM were mixed in dichloromethane, ultrasonicated for 10 min to make them dispersed evenly, and then stirred at room temperature for 24 hours. Next, the supernatant was removed by centrifugation, and the remaining solid was dried in a vacuum oven at room temperature for 24 hours. The product was recorded as simvastatin-loaded mesoporous silica nanoparticles SIM@MSN; 3) SIM@MSN was weighed and dispersed in PBS. 100 μl of PEI solution was slowly added to the nano solution at 500 rpm and stirred at room temperature for 30 min. The product was then centrifuged, washed with water for 3 times, and stored at 4°C. This was recorded as simvastatin-loaded polyethyleneimine-coated mesoporous silica nanoparticles SIM@PEI-MSN. 4), HA, NHS and EDC were dissolved in ultrapure water and stirred for 1 h to activate the carboxyl groups, and then SIM@PEI-MSN was added. After ultrasonic dispersion for 10 min, stirring was continued for 24 h. The product was then centrifuged, washed with water three times, and freeze-dried overnight. The product was recorded as an enzyme-responsive silica-release nanoformulation SIM@HA-MSN.

2. A method for preparing an enzyme-responsive silica nanoformulation according to claim 1, characterized in that: The preparation method of the enzyme-responsive silica nanoformulation comprises the following steps: 1) preparing mesoporous silica nanoparticles in an alkaline environment, and obtaining mesoporous silica nanoparticle powder after drying and calcining; 2) dissolving mesoporous silica nanoparticles and simvastatin in a solvent, collecting a sample after the reaction is complete, and obtaining mesoporous silica nanoparticles encapsulating simvastatin; 3) adding polyethyleneimine to the mesoporous silica nanoparticles encapsulating simvastatin obtained in 2), collecting a sample after the reaction is complete, and obtaining polyethyleneimine-modified mesoporous silica nanoparticles encapsulating simvastatin; 4) adding the activated sodium hyaluronate to the polyethyleneimine-modified mesoporous silica nanoparticles loaded with simvastatin obtained in 3) to react, collecting the sample after the reaction is complete, and finally obtaining an enzyme-responsive silica nanoformulation; 1), dissolving hexadecyl ammonium bromide and sodium hydroxide in ultrapure water, stirring and heating to 80°C, adding anhydrous ethanol after the solution is completely clarified, stirring for 5 minutes, and then slowly dropping ethyl orthosilicate solution, reacting at 80°C for 2 hours, centrifuging, washing with distilled water 3 times, washing with methanol once, and then transferring the product to an evaporating dish, drying in a constant temperature oven overnight, and transferring the product to a muffle furnace after it is completely dried, calcining at 550°C for 5 hours, and finally obtaining a white powder, which is recorded as mesoporous silica nanoparticles MSN; 2), MSN and simvastatin SIM were mixed in dichloromethane, ultrasonicated for 10 min to make them dispersed evenly, and then stirred at room temperature for 24 hours. Next, the supernatant was removed by centrifugation, and the remaining solid was dried in a vacuum oven at room temperature for 24 hours. The product was recorded as simvastatin-loaded mesoporous silica nanoparticles SIM@MSN; 3) SIM@MSN was weighed and dispersed in PBS. 100 μl of PEI solution was slowly added to the nano solution at 500 rpm and stirred at room temperature for 30 min. The product was then centrifuged, washed with water for 3 times, and stored at 4°C. This was recorded as simvastatin-loaded polyethyleneimine-coated mesoporous silica nanoparticles SIM@PEI-MSN. 4), HA, NHS and EDC were dissolved in ultrapure water and stirred for 1 h to activate the carboxyl groups, and then SIM@PEI-MSN was added. After ultrasonic dispersion for 10 min, stirring was continued for 24 h. The product was then centrifuged, washed with water three times, and freeze-dried overnight. The product was recorded as an enzyme-responsive silica-release nanoformulation SIM@HA-MSN.

3. The method for preparing an enzyme-responsive silica nanoformulation according to claim 1, characterized in that: 2) The mass ratio of the mesoporous silica nanoparticles to simvastatin is 2:1-2; the concentration of simvastatin in the solvent is 15-30 mg / ml.

4. The method for preparing an enzyme-responsive silica nanoformulation according to claim 3, characterized in that: 3) The concentration of polyethyleneimine in the solution is 2 mg / ml.

5. The method for preparing an enzyme-responsive silica nanoformulation according to claim 1, characterized in that: 1), dissolving hexadecyl ammonium bromide and sodium hydroxide in ultrapure water, stirring and heating to 80°C, adding anhydrous ethanol after the solution is completely clarified, stirring for 5 minutes, and then slowly dropping ethyl orthosilicate solution, reacting at 80°C for 2 hours, centrifuging, washing with distilled water 3 times, washing with methanol once, and then transferring the product to an evaporating dish, drying in a constant temperature oven overnight, and transferring the product to a muffle furnace after it is completely dried, calcining at 550°C for 5 hours, and finally obtaining a white powder, which is recorded as mesoporous silica nanoparticles MSN; 2), MSN and simvastatin SIM were mixed in dichloromethane, ultrasonicated for 10 min to make them dispersed evenly, and then stirred at room temperature for 24 hours. Next, the supernatant was removed by centrifugation, and the remaining solid was dried in a vacuum oven at room temperature for 24 hours. The product was recorded as simvastatin-loaded mesoporous silica nanoparticles SIM@MSN; 3) SIM@MSN was weighed and dispersed in PBS. 100 μl of PEI solution was slowly added to the nano solution at 500 rpm and stirred at room temperature for 30 min. The product was then centrifuged, washed with water for 3 times, and stored at 4°C. This was recorded as simvastatin-loaded polyethyleneimine-coated mesoporous silica nanoparticles SIM@PEI-MSN. 4), HA, NHS and EDC were dissolved in ultrapure water and stirred for 1 h to activate the carboxyl groups, and then SIM@PEI-MSN was added. After ultrasonic dispersion for 10 min, stirring was continued for 24 h. The product was then centrifuged, washed with water three times, and freeze-dried overnight. The product was recorded as an enzyme-responsive silica-release nanoformulation SIM@HA-MSN.

6. An application of the enzyme-responsive silica nanoformulation according to claim 1, characterized in that It is used in the preparation of drugs for treating atherosclerosis.

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