Construction and application of mesoporous polydopamine nano preparation loaded with ultra-small nano enzyme

Abstract

The invention belongs to the field of biomedical materials, and discloses a preparation method and application of a mesoporous polydopamine nano preparation loaded with ultra-small nano enzyme. The nano preparation takes mesoporous polydopamine nanoparticles as a carrier skeleton and is combined with ultra-small nano enzyme through an in-situ reaction: the mesoporous polydopamine nanoparticles can efficiently carry drugs and accurately deliver the drugs to inflammatory tissues such as psoriasis, gout, colitis and the like by virtue of a modified targeting ligand by virtue of high specific surface area, biocompatibility and modifiability; the ultra-small nano enzyme has catalytic activity of catalase and the like, and can remove active oxygen and relieve oxidative stress. The two components are combined to achieve a synergistic effect, so that the catalytic efficiency of the enzyme is improved by virtue of the characteristics of the carrier, the high activity of the enzyme under different conditions is maintained by virtue of the stability of the carrier, and the platform can synchronously realize targeted delivery, enzymatic treatment and drug controlled release, and has a wide application prospect in the fields of inflammatory disease intervention and wound repair. And an efficient, accurate and low-toxicity universal treatment strategy is provided for chronic inflammatory diseases.

Description

Technical Field

[0001] This invention belongs to the field of preparation and application of biomedical materials, specifically relating to a mesoporous polydopamine nanoparticle loaded with ultrasmall nanozymes, and further disclosing the preparation process of the nanoparticle and its application in inflammation intervention. Background Technology

[0002] Chronic inflammatory diseases are a serious threat to human health, characterized by dysregulation of the body's immune response and persistent oxidative stress. During disease progression, the dysregulated immune response and excessive reactive oxygen species continuously attack normal tissues, leading to tissue damage and further triggering systemic complications. This poses a significant threat to patients' quality of life and safety. Therefore, developing efficient and precise diagnostic and treatment methods for these diseases has become an important research direction in the biomedical field.

[0003] Among the many applications of nanotechnology, nanomedicine carriers have become a research hotspot in the biomedical field due to their core advantages such as targeted drug delivery, improved drug solubility, and reduced toxicity. However, they also face numerous technical bottlenecks that severely restrict their clinical translation and application. These bottlenecks include: limited functionality (most nanomedicine carriers only have a single drug delivery function); insufficient biosafety (traditional nanocarriers (such as silica and carbon nanotubes) degrade slowly in vivo and tend to accumulate in organs such as the liver and spleen, potentially causing adverse effects such as cytotoxicity and inflammatory reactions with long-term use, resulting in potential damage to the body); and limited targeting precision (existing nanocarriers generally lack efficient targeting mechanisms, making it difficult to accurately identify and accumulate at inflammatory lesions, resulting in a large amount of drug being distributed in non-lesioned tissues, which reduces the therapeutic effect and increases the risk of toxic side effects on normal tissues).

[0004] Mesoporous polydopamine exhibits excellent biocompatibility and surface modifiability. Its surface is rich in functional groups such as hydroxyl and amino groups, which facilitates the binding of targeting ligands to improve targeting accuracy. At the same time, functional molecules can be immobilized through cross-linking agents. Mesoporous polydopamine possesses unique photothermal conversion properties, which can be used for photothermal therapy. Its mesoporous structure can efficiently load therapeutic agents such as chemotherapy drugs and photosensitizers, realizing the integration of multiple therapeutic functions. Mesoporous polydopamine can be gradually degraded in acidic or reducing environments (such as the microenvironment of chronic inflammatory lesions), effectively reducing the risk of accumulation of nanomaterials in vivo and improving biosafety.

[0005] In chronic inflammatory lesions, abnormally high expression of reactive oxygen species (ROS) is a key factor exacerbating oxidative stress and tissue damage. Natural enzymes such as catalase and superoxide dismutase are known to possess excellent antioxidant catalytic activity, effectively scavenging excess ROS to regulate oxidative stress levels. However, the poor stability, easy inactivation, and difficulty in targeted delivery of natural enzymes limit their clinical application. To address this, researchers have developed a series of nanomaterials with antioxidant enzyme functions, such as ultrasmall nanozymes: metal nanozymes (cerium oxide, platinum, iron-based nanoparticles, etc.) and carbon dots. As novel enzyme mimics, they possess the physicochemical properties of nanomaterials and the catalytic activity of enzymes, achieving anti-inflammatory and other therapeutic functions by regulating ROS levels in vivo.

[0006] When applied directly, ultrasmall nanozymes are easily inactivated by complex physiological environments (such as pH fluctuations and protease degradation), and they struggle to precisely reach the target sites of inflammatory lesions, thus failing to fully realize their anti-inflammatory therapeutic functions. To address the challenges of clinical translation of ultrasmall nanozymes, mesoporous polydopamine is combined with them. Polydopamine, a biocompatible and degradable polymer inspired by mussel adhesion proteins, serves as the carrier framework for ultrasmall nanozymes. This not only significantly improves the stability and cellular uptake efficiency of nanoparticles but also leverages its natural anti-inflammatory and antioxidant properties to further enhance the therapeutic effects of the nanozymes. More importantly, the biocompatibility and degradability of polydopamine effectively improve the long-term biosafety of ultrasmall nanozymes, such as metalloenzymes, reducing potential off-target effects. Currently, research on such mesoporous polydopamine nanoformulations loaded with ultrasmall nanozymes is still in the exploratory stage, and mature preparation processes and application systems have not yet been established. Therefore, developing a structurally controllable, functionally synergistic, and biosafe mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes has significant theoretical and clinical application value. Summary of the Invention

[0007] To address the limitations of existing nanomedicine carriers, such as limited functionality, insufficient biosafety, and unstable physicochemical activity of ultrasmall nanozymes, this invention provides a mesoporous polydopamine nanoparticle formulation loaded with ultrasmall nanozymes. Furthermore, the preparation process of this nanoparticle formulation and its application in inflammation intervention are disclosed. This platform, through the rational design of the "mesoporous polydopamine nanoparticle carrier-ultrasmall nanozyme-drug" structure, achieves functional integration of enzyme-catalyzed therapy, controlled drug release, and multimodal synergistic therapy, providing a new solution for the treatment of inflammatory diseases.

[0008] The specific technical solution of the present invention is as follows:

[0009] A mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes has a core structure comprising two parts:

[0010] Mesoporous polydopamine nanoparticles: As a carrier framework, they provide high specific surface area and porous structure for loading drugs and immobilizing ultrasmall nanozymes, while also possessing photothermal conversion properties;

[0011] Ultrasmall nanozymes: deposited in situ on the interior and surface of mesoporous polydopamine nanoparticles, they endow the platform enzyme with catalytic activity and can regulate the level of reactive oxygen species in vivo.

[0012] The mesoporous polydopamine nanoparticles are spherical with a hydrated particle size of 50-300 nm. The mesopores can load most small molecule drugs and ultrasmall nanozymes, thereby increasing the drug loading capacity.

[0013] Ultra-small nanozymes: preferably gold nanozymes, platinum nanozymes, or selenium-based nanozymes (antioxidant activity).

[0014] The mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes of the present invention is prepared by a stepwise synthesis method, the specific steps of which are as follows:

[0015] The mesoporous polydopamine nanoparticles were prepared by dispersing poloxamer, dopamine hydrochloride and 1,3,5-trimethylbenzene in an aqueous ethanol solution, then adding ammonia and reacting the mixture hydrothermally at 30°C to 65°C.

[0016] Preferably, the ratio of poloxamer: dopamine hydrochloride: 1,3,5-trimethylbenzene is 0.1–0.5 g: 0.1–0.5 g: 0.16 mL–0.8 mL;

[0017] Preferably, in the aqueous ethanol solution, the volume ratio of ethanol to water is 1:1;

[0018] Preferably, the hydrothermal reaction time is 3 hours;

[0019] Preferably, the hydrothermal temperature is 45°C;

[0020] Preferably, the product is collected by centrifugation, washed 3 to 5 times with a mixed solvent of ethanol and acetone at a volume ratio of 2:1, and then washed 2 to 3 times with ultrapure water to remove unreacted dopamine hydrochloride, thereby obtaining mesoporous polydopamine nanoparticles.

[0021] The preparation of the ultrasmall nanoenzyme bound to the mesoporous polydopamine nanoparticles includes the following steps: adding a metal salt solution to an aqueous dispersion of mesoporous polydopamine nanoparticles, stirring at room temperature for 20-40 min, then adding an aqueous solution of sodium borohydride, continuing to stir at room temperature for 20 min, centrifuging to collect the product and washing it twice with ultrapure water to obtain the in-situ loaded ultrasmall nanoenzyme mesoporous polydopamine nanoformulation.

[0022] Preferably, the metal salt solution includes tetrachloroauric acid, chloroplatinic acid, sodium chloropalladium, nickel chloride, copper chloride, bismuth nitrate, and sodium selenite solution;

[0023] Preferably, the mass ratio of the aqueous dispersion of mesoporous polydopamine nanoparticles to the metal salt solution is 1:2 to 2:1;

[0024] Preferably, the mass ratio of metal salt solution to sodium borohydride aqueous solution is 4:1 to 1:4.

[0025] The mesoporous polydopamine nanoparticles loaded with ultrasmall nanozymes of the present invention, with their targeting, enzymatic activity, drug loading capacity and degradability, can be widely used in the treatment of inflammatory diseases: after loading anti-inflammatory drugs (such as baicalin and tofacitinib citrate) and targeting and enriching them at the lesion site, ultrasmall nanozymes such as platinum-based nanozymes can clear excess reactive oxygen species at the inflammatory site, relieve oxidative stress and inflammatory response, and are suitable for rheumatoid arthritis, ulcerative colitis and psoriasis, etc. For example, in a specific example, the mesoporous polydopamine nanoparticles loaded with ultrasmall nanozymes of the present invention can be loaded with baicalin for the treatment of psoriatic inflammation.

[0026] The beneficial effects of this invention are:

[0027] Compared with the prior art, the present invention has the following significant advantages:

[0028] Mesoporous polydopamine nanoparticles, as carriers, possess high specific surface area, biocompatibility, and modifiability. Ultrasmall nanozymes exhibit high catalytic activity. The mesoporous structure of mesoporous polydopamine nanoparticles provides an ideal carrier environment for ultrasmall nanozymes. The two can be linked by physical adsorption or chemical covalent bonding, such as by reacting the hydroxyl and amino groups on the carrier surface with the functional groups on the enzyme surface to form a covalent connection, thereby stably loading the enzyme inside or on the surface of the carrier mesopores.

[0029] The combination of these two components has a synergistic effect. On the one hand, it can improve catalytic efficiency. The high specific surface area of ​​the support allows the active sites of the enzyme to be fully exposed, increasing the opportunity for contact with the substrate. The mesoporous structure can also enrich the substrate, increase the local concentration, and promote the catalytic reaction. On the other hand, it can enhance stability. The biocompatibility and chemical stability of the support can buffer the influence of the external environment, reduce the inactivation of the enzyme in complex environments, and enable it to maintain high catalytic activity at different pH values ​​and temperatures, while the activity of unsupported enzymes will be significantly inhibited.

[0030] The preparation process is simple and controllable, using a stepwise synthesis method. The parameters of each step are easy to adjust, and the type of nanozyme, targeting ligand, and loaded drug can be changed according to different treatment needs, making it widely applicable. Attached Figure Description

[0031] Figure 1 Hydrated particle size diagram of mesoporous polydopamine nanoparticles;

[0032] Figure 2 This is a transmission electron microscope (TEM) image of mesoporous polydopamine nanoparticles.

[0033] Figure 3 This is a transmission electron microscope (TEM) image of mesoporous polydopamine nanoparticles loaded with ultrasmall nanozymes.

[0034] Figure 4 Mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoformulations loaded with ultrasmall nanozymes for ABTS removal .+ Verification;

[0035] Figure 5 Mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoformulations loaded with ultrasmall nanozymes for DPPH removal . Verification;

[0036] Figure 6 Verification of the removal of ·OH by mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoformulations loaded with ultrasmall nanozymes;

[0037] Figure 7 The effect of mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes on the viability of HACAT cells;

[0038] Figure 8 This is a schematic diagram illustrating the effect of drug-loaded nanoparticles on the skin of mice's backs.

[0039] Figure 9 Comparison of spleen index between the psoriasis model group and the drug-loaded nanoparticle group. Detailed Implementation

[0040] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented based on the technical solution of the present invention and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0041] Example 1

[0042] This example demonstrates a method for preparing mesoporous polydopamine nanoparticles under a heating condition of 30°C, including the following steps:

[0043] 0.5 g of poloxamer, 0.5 g of dopamine hydrochloride, and 0.8 mL of 1,3,5-trimethylbenzene were dispersed in a mixture of 25 mL of water and 25 mL of ethanol, and an emulsion was formed by ultrasonic treatment. Then, 2 mL of ammonia water was added to the reaction mixture under stirring, and the mixture was reacted at 30 °C for 3 h. The product was collected by centrifugation, washed multiple times with a mixed solvent of ethanol and acetone, and then washed several times with ultrapure water to obtain mesoporous polydopamine nanoparticles with a hydrated particle size of 300 nm.

[0044] Example 2

[0045] This example demonstrates a method for preparing mesoporous polydopamine nanoparticles under a heating condition of 45°C, including the following steps:

[0046] 0.5 g of poloxamer, 0.5 g of dopamine hydrochloride, and 0.8 mL of 1,3,5-trimethylbenzene were dispersed in a mixture of 25 mL of water and 25 mL of ethanol, and an emulsion was formed by sonication. Then, 2 mL of ammonia was added to the reaction mixture under stirring, and the mixture was reacted at 45 °C for 3 h. The product was collected by centrifugation, washed multiple times with a mixed solvent of ethanol and acetone, and then washed several times with ultrapure water. Figure 1 Mesoporous polydopamine nanoparticles with a hydrated particle size of 175.5 nm were obtained.

[0047] Example 3

[0048] This example demonstrates a method for preparing mesoporous polydopamine nanoparticles under a heating condition of 60°C, including the following steps:

[0049] 0.5 g of poloxamer, 0.5 g of dopamine hydrochloride, and 0.8 mL of 1,3,5-trimethylbenzene were dispersed in a mixture of 25 mL of water and 25 mL of ethanol, and an emulsion was formed by ultrasonic treatment. Then, 2 mL of ammonia water was added to the reaction mixture under stirring, and the mixture was reacted at 60 °C for 3 h. The product was collected by centrifugation, washed multiple times with a mixed solvent of ethanol and acetone, and then washed several times with ultrapure water to obtain mesoporous polydopamine nanoparticles with a hydrated particle size of 450 nm.

[0050] Example 4

[0051] This example demonstrates a method for preparing mesoporous polydopamine nanoparticles by removing the template through heating and stirring for 24 hours, including the following steps:

[0052] 0.5 g of poloxamer, 0.5 g of dopamine hydrochloride, and 0.8 mL of 1,3,5-trimethylbenzene were dispersed in a mixture of 25 mL of water and 25 mL of ethanol, and an emulsion was formed by sonication. Then, 2 mL of ammonia was added to the reaction mixture under stirring, and the mixture was reacted at 45 °C for 3 h. The product was collected by centrifugation, heated and stirred at 30 °C for 24 h to remove the template, and then washed several times with ultrapure water. A precipitate formed in the aqueous solution.

[0053] Example 5

[0054] This example demonstrates a method for preparing mesoporous polydopamine nanoparticles by repeatedly washing with a mixed solvent of ethanol and acetone to remove the template, including the following steps:

[0055] 0.5 g of poloxamer, 0.5 g of dopamine hydrochloride, and 0.8 mL of 1,3,5-trimethylbenzene were dispersed in a mixture of 25 mL of water and 25 mL of ethanol, and an emulsion was formed by ultrasonic treatment. Then, 2 mL of ammonia water was added to the reaction mixture under stirring, and the mixture was reacted at 45 °C for 3 h. The product was collected by centrifugation, washed multiple times with a mixed solvent of ethanol and acetone, and then washed several times with ultrapure water to obtain mesoporous polydopamine nanoparticles with a hydrated particle size of 175.50 nm.

[0056] Figure 2 The image shows a transmission electron microscope (TEM) image of the mesoporous polydopamine nanoparticles prepared in Example 5. As can be seen from the image, the mesoporous polydopamine nanoparticles are well dispersed and have a uniform particle size, resembling mesoporous spheres.

[0057] Example 6

[0058] This example demonstrates a method for preparing ultrasmall nanozymes loaded on mesoporous polydopamine nanoparticles, comprising the following steps:

[0059] A metal salt solution was added to an aqueous dispersion of mesoporous polydopamine nanoparticles, and the mixture was stirred at room temperature for 30 min. Then, an aqueous solution of sodium borohydride was added, and the mixture was stirred at room temperature for another 20 min. The product was collected by centrifugation and washed twice with ultrapure water to obtain a mesoporous polydopamine nanoformulation with in-situ bound ultrasmall nanozymes. Figure 3 As shown, ultrasmall nanozymes are uniformly loaded on the surface and mesoporous polydopamine nanoparticles.

[0060] Example 7

[0061] This example tests the antioxidant properties of mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoformulations loaded with ultrasmall nanozymes according to the following steps:

[0062] A certain concentration of mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoparticles loaded with ultrasmall nanozymes were mixed evenly with ABTS working solution and allowed to react at room temperature in the dark for a period of time. The absorbance at 734 nm was measured using a microplate reader, and the clearance rate was calculated. Figure 4 As shown, mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoformulations loaded with ultrasmall nanozymes have the ability to scavenge ABTS. .+ The ability.

[0063] A certain concentration of mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoparticles loaded with ultrasmall nanozymes were mixed evenly with DPPH detection solution and allowed to react at room temperature in the dark for a period of time. The absorbance at 517 nm was measured using an enzyme-linked immunosorbent assay (ELISA) reader, and the clearance rate was calculated. Figure 5 As shown, mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoformulations loaded with ultrasmall nanozymes have the ability to scavenge DPPH. . The ability.

[0064] The ·OH scavenging assay was performed using the TMB colorimetric method to determine whether mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoparticles loaded with ultrasmall nanozymes possessed the ability to scavenge ·OH. Specifically, a certain concentration of mesoporous polydopamine nanoparticles and mesoporous polydopamine loaded with ultrasmall nanozymes were mixed thoroughly with TMB detection solution and allowed to react at room temperature in the dark for a period of time. The absorbance at 650 nm was measured using a microplate reader, and the scavenging rate was calculated. Figure 6 As shown, mesoporous polydopamine nanoparticles and mesoporous polydopamine nanoformulations loaded with ultrasmall nanozymes have the ability to scavenge ·OH.

[0065] Example 8

[0066] This example demonstrates the preparation of mesoporous polydopamine nanoparticles loaded with in-situ bound ultrasmall nanozymes and the calculation of the drug loading capacity, including the following steps:

[0067] Baicalein was completely dissolved in anhydrous ethanol. Aqueous dispersions of mesoporous polydopamine nanoparticles with in-situ bound ultra-small nanozymes were added dropwise under slow stirring. The mixture was stirred at room temperature in the dark for a period of time, and the reaction solution was collected. The supernatant was collected by centrifugation and filtered through a microporous membrane. The filtrate was diluted several times and its UV absorption in the range of 200–400 nm was measured. The drug loading and encapsulation efficiency were calculated.

[0068] Drug loading = |(Supernatant concentration * Dilution factor * Reaction liquid volume) - Mass of drug weighed| / Total mass of nanoparticles * 100%

[0069] Encapsulation efficiency = |(Supernatant concentration * Dilution factor * Reaction liquid volume) - Mass of drug weighed| / Mass of drug weighed * 100%

[0070] Calculations showed that the drug loading and encapsulation efficiency of the mesoporous polydopamine nanoparticles carrying the in-situ bound ultrasmall nanozymes were 56.23% and 29.3%, respectively, indicating that the carrier has excellent drug loading performance.

[0071] Example 9

[0072] This example demonstrates the biocompatibility study of mesoporous polydopamine nanoformulations with in-situ bound ultrasmall nanozymes, including the following steps:

[0073] The effect of in-situ bound ultrasmall nanozymes in mesoporous polydopamine nanoparticles on HACAT cell viability was determined using the MTT assay. Specifically, HACAT cells were seeded in diluted form on 96-well plates and incubated for 12 hours. The culture medium was then discarded, and aqueous dispersions of mesoporous polydopamine nanoparticles at different concentrations were added. Incubation was continued for 24 hours, followed by washing with PBS and the addition of MTT solution. Incubation was continued for another 4 hours, and then dimethyl sulfoxide solution was added. The absorbance at 490 nm was measured using a microplate reader. Figure 7As shown, the cell viability of the mesoporous polydopamine nanoparticles loaded with ultrasmall nanozymes is greater than 85%, indicating that the nanoparticles have good biocompatibility.

[0074] Example 10

[0075] This example examines the therapeutic effect of mesoporous polydopamine nanoformulation with in-situ bound ultrasmall nanozymes on psoriasis, and includes the following steps:

[0076] The backs of mice were shaved to create an area of ​​approximately 2 cm x 2 cm, and the shaved area was treated with depilatory cream. The mice were then fed normally for 12 hours to allow the stratum corneum (the outermost layer of skin) to recover. Subsequently, the mice were randomly divided into two groups of three mice each. For the next six days, imiquimod cream was administered daily to induce a psoriasis model, followed by administration 5 hours later. The mice's weight was recorded daily, and photographs of the back skin were taken to document lesion progression. On day 6, major organs (heart, liver, spleen, lungs, and kidneys) were harvested from the mice for further analysis.

[0077] Control group: Imiquimod cream was applied in the morning to establish the model, and no treatment was received in the afternoon;

[0078] Drug-loaded nanoparticle formulation group: Imiquimod cream was applied in the morning, and in the afternoon, mesoporous polydopamine nanoparticles containing baicalin and in situ bound to platinum nanoenzymes were delivered transdermally with ionic liquid for treatment.

[0079] Figure 8 This is a schematic diagram illustrating the effect of drug-loaded nanoparticles on the skin of mice. As can be seen from the figure, the model group exhibited phenotypes such as epidermal thickening, increased scaling, and erythema, while the drug-loaded nanoparticle group showed significant improvement.

[0080] Figure 9 The spleen index was compared between the control group and the drug-loaded nanoparticle group. The results showed that the spleen index of the drug-loaded nanoparticle group was lower than that of the model group.

[0081] The results of Example 10 demonstrate that the mesoporous polydopamine nanoparticle formulation containing baicalin and in situ bound to platinum nanozyme has a significant therapeutic effect on psoriasis.

[0082] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes, characterized in that, include: Mesoporous polydopamine nanoparticles serving as a carrier framework; Ultrasmall nanozymes are bound to the mesoporous polydopamine nanoparticles through in-situ reactions within the mesopores and on the surface.

2. The mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes according to claim 1, characterized in that, The hydrated particle size of the mesoporous polydopamine nanoparticles is 50–300 nm.

3. The mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes according to claim 1, characterized in that, The ultrasmall nanozymes are selected from at least one of gold nanozymes, palladium nanozymes, platinum nanozymes, nickel nanozymes, copper nanozymes, bismuth nanozymes, and selenium nanozymes.

4. The mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes according to claim 1, characterized in that, The preparation method includes the following steps: (1) Poloxamer, dopamine hydrochloride and 1,3,5-trimethylbenzene were dispersed in an ethanol aqueous solution, 0.4 mL to 2.0 mL of ammonia water was added and heated to react. The mixture was washed 3 to 5 times with a mixture of ethanol and acetone, then washed with ultrapure water and centrifuged to obtain mesoporous polydopamine nanoparticles. (2) Take the aqueous dispersion of mesoporous polydopamine nanoparticles obtained in step (1), add a metal salt solution, stir at room temperature, then add sodium borohydride aqueous solution, continue stirring at room temperature, centrifuge to collect the product and wash with ultrapure water, centrifuge to obtain mesoporous polydopamine nanoparticles loaded with ultrasmall nanozymes.

5. The mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes according to claim 4, characterized in that, In preparation step (1), the ratio of poloxamer: dopamine hydrochloride: 1,3,5-trimethylbenzene is 0.1-0.5g: 0.1-0.5g: 0.16mL-0.8mL.

6. The mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes according to claim 4, characterized in that, The metal salt solution in preparation step (2) is selected from at least one of tetrachloroauric acid, chloroplatinic acid, sodium chloropalladium, nickel chloride, copper chloride, bismuth nitrate and sodium selenite solution.

7. The preparation of the mesoporous polydopamine nanoformulation loaded with ultrasmall nanozymes as described in claim 1 and its application in chronic inflammatory diseases.

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