Polydopamine encapsulated chloroplast nano material as well as preparation method and application thereof

Abstract

The invention discloses a polydopamine encapsulated chloroplast nanometer material and a preparation method and application thereof, and belongs to the technical field of nanometer materials, the preparation method of the polydopamine encapsulated chloroplast nanometer material comprises the following steps: (1) mixing a sodium alginate solution and a chloroplast extracting solution to obtain a mixed solution; and (2) adding a dopamine solution and an alkali solution into the mixed solution, and carrying out a polymerization reaction. The chloroplast is packaged by polydopamine in a self-assembly mode, a novel nano material is constructed and plays a role in oxidation resistance and treatment of inflammatory bowel diseases, and a new thought is provided for treatment of related diseases.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, and more specifically, to a polydopamine-encapsulated chloroplast nanomaterial, its preparation method, and its application. Background Technology

[0002] Inflammatory bowel disease (IBD) is a group of chronic, relapsing, nonspecific inflammatory bowel diseases, mainly including ulcerative colitis and Crohn's disease. Its pathogenesis is complex and closely related to impaired intestinal barrier function, excessive oxidative stress, and dysregulation of the immune inflammatory response. Current clinical treatments suffer from limited efficacy, significant side effects, and a high risk of drug resistance. Therefore, the development of safe and effective novel therapeutic materials has significant clinical need and research value.

[0003] Nanomaterials, with their unique structure and properties, have shown broad application prospects in the biomedical field. Polydopamine (PDA) possesses excellent biocompatibility, adhesion, and antioxidant properties, and is often used as a nanocoating material. Chloroplasts, as important organelles for plant photosynthesis, possess certain biological activity and are widely available and easily extracted. Encapsulating chloroplasts with PDA through self-assembly to construct novel nanomaterials holds promise for combining the advantages of both, potentially playing a role in antioxidant activity and the treatment of inflammatory bowel disease, providing new insights for the treatment of related diseases. Summary of the Invention

[0004] To address the above technical problems, this invention provides a polydopamine-encapsulated chloroplast nanomaterial, its preparation method, and its application.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing polydopamine-encapsulated chloroplast nanomaterials, comprising the following steps: (1) Sodium alginate solution and chloroplast extract were mixed to obtain a mixture; (2) Add dopamine solution and alkaline solution to the mixture to carry out the polymerization reaction, and the product is obtained.

[0007] In some embodiments, the concentration of the sodium alginate solution in step (1) is 200-400 μg / mL, for example 200 μg / mL, 250 μg / mL, 300 μg / mL, 350 μg / mL or 400 μg / mL, or any range derived therefrom, preferably 300-400 μg / mL.

[0008] In some embodiments, the chloroplast extract in step (1) is 1-3 mg / mL, for example 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL or 3 mg / mL, or any derivative thereof, preferably 2-3 mg / mL.

[0009] In some embodiments, the mass ratio of chloroplasts to sodium alginate in the mixture in step (1) is 3-10:1; for example, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, or any range derived therefrom, preferably 4-6:1.

[0010] In some embodiments, the concentration of the dopamine solution in step (2) is 100-300 μg / mL; for example, 100 μg / mL, 150 μg / mL, 200 μg / mL, 250 μg / mL or 300 μg / mL, or any range derived therefrom, preferably 100-200 μg / mL.

[0011] In some embodiments, the concentration of the alkaline solution in step (2) is 0.1-0.4 mol / L; for example, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L or 0.4 mol / L, or any range derived therefrom, preferably 0.1-0.2 M.

[0012] In some implementations, the volume ratio of the mixture, dopamine solution and alkaline solution in step (2) is 4-5:1:0.3-0.7; preferably 4.5:1:0.5.

[0013] In some embodiments, the alkali in step (2) includes at least one of sodium hydroxide and potassium hydroxide.

[0014] In some embodiments, the polymerization reaction in step (2) is carried out at 2-6°C for 1-5 hours; preferably at 4°C for 3 hours.

[0015] Secondly, the present invention provides polydopamine-encapsulated chloroplast nanomaterials prepared by the above preparation method.

[0016] Thirdly, the present invention provides a pharmaceutical formulation containing polydopamine-encapsulated chloroplast nanomaterials, which is made from the above-mentioned polydopamine-encapsulated chloroplast nanomaterials and pharmaceutically acceptable excipients.

[0017] In some embodiments, the dosage form of the pharmaceutical preparation is tablets, capsules, granules, pills, powders, syrups, oral solutions, oral suspensions, oral emulsions, mixtures, or injections.

[0018] Fourthly, the present invention provides the application of the aforementioned polydopamine-encapsulated chloroplast nanomaterials in the preparation of drugs.

[0019] The drug of this invention has at least one of the following effects: (1) Antioxidant; (2) Anti-inflammatory; (3) Treatment of enteritis; (4) Repair the intestinal barrier.

[0020] Preferably, the antioxidant includes scavenging at least one of ABTS, •OH free radicals and superoxide anion free radicals, as well as inhibiting superoxide dismutase (SOD).

[0021] The beneficial effects of this invention are as follows: (1) The polydopamine-encapsulated chloroplast nanomaterial (PDA@Chloroplast) prepared in this invention has good structure and stability, which is beneficial for biomedical applications.

[0022] (2) The PDA@Chloroplast of the present invention has excellent and rapid free radical scavenging ability and exhibits excellent multiple antioxidant properties against a variety of free radicals in vitro.

[0023] (3) The PDA@Chloroplast of the present invention can promote the expression of tight junction protein in intestinal epithelial cells, improve DSS-induced intestinal barrier damage, and inhibit the expression of pro-inflammatory factors and promote the production of anti-inflammatory factors, thereby achieving the improvement and treatment of enteritis. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the PDA@Chloroplast preparation method.

[0025] Figure 2 The image shows the characterization results of the PDA@Chloroplast prepared in Example 1-1; where the scale bar is 2 μm.

[0026] Figure 3 The image shows the in vitro antioxidant performance test results of PDA@Chloroplast prepared in Example 1-1.

[0027] Figure 4 The effect of PDA@Chloroplast prepared in Example 1-1 on DSS-induced enteritis in mice; where n=3, p < 0.001, p < 0.0001.

[0028] Figure 5Typical images of H&E and AB-PAS staining in mouse colon.

[0029] Figure 6 Immunohistochemical staining images of ZO-1, Occludin, and E-Cadherin in colon tissue.

[0030] Figure 7 The image shows immunofluorescence staining, where CD86 and CD206 are red, F4 / 80 is green, and DAPI is blue.

[0031] Figure 8 The levels of inflammatory and anti-inflammatory factors in the mouse gut were detected by qRT-PCR; among them, p < 0.001, p < 0.0001.

[0032] Figure 9 Results and statistical graphs of flow cytometry analysis; p < 0.05 p < 0.01, p < 0.001, p < 0.0001. Detailed Implementation

[0033] The following description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0034] Therefore, the present invention is not to be limited to the embodiments shown herein, but can be applied to a wider scope consistent with the principles and novel features disclosed herein. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0035] As used in the specification and claims, the singular forms “a,” “an,” and “the (described)” include the plural forms, unless the context clearly indicates otherwise.

[0036] All numerical values ​​or expressions relating to component amounts, process conditions, etc., used in this invention shall be understood to be modified by the word "about" in all cases. When referring to a quantity or range of values, the quantity or range is an approximation within experimental variability (or within statistical experimental error). In this invention, the term "about" shall have the meaning of being within 10%, preferably within 5%, of the specified value or range.

[0037] All ranges relating to the same component or property include endpoints that can be combined independently. Because these ranges are continuous, they encompass every numerical value between the minimum and maximum value. It should also be understood that any numerical range referenced in this invention is intended to include all subranges within that range.

[0038] The “pharmaceutical formulation” described in this invention comprises the above-mentioned polydopamine-encapsulated chloroplast nanomaterial and pharmaceutically acceptable excipients. In a specific embodiment, the polydopamine-encapsulated chloroplast nanomaterial described in this invention is provided in the pharmaceutical formulation in an effective amount (e.g., a therapeutically effective amount).

[0039] The "acceptable" ingredient as described in this invention is a substance suitable for human and / or animal use without excessive adverse side effects (such as toxicity, irritation, and allergic reactions), i.e., a reasonable benefit / risk ratio. The "pharmaceuticalally acceptable excipients" include at least one of inert diluents, dispersants, granulators, surfactants, emulsifiers, disintegrants, binders, preservatives, buffers, and lubricants. The pharmaceutical formulation may also contain excipients, colorants, coating agents, sweeteners, and flavoring agents.

[0040] The “pharmaceutical formulation” described in this invention can be prepared by any method known in pharmaceutical science. Generally, these preparation methods involve associating the polydopamine-encapsulated chloroplast nanomaterial (hereinafter referred to as the active ingredient) with a carrier or excipient and / or one or more other auxiliary ingredients, and then, if desired and / or expected, shaping and / or packaging the product into desired single-dose or multi-dose units.

[0041] The "pharmaceutical formulation" of this invention can be prepared according to known methods, such as those described in the general rules for preparation in the Chinese Pharmacopoeia 2025, the Japanese Pharmacopoeia 16th edition, the United States Pharmacopoeia, and the European Pharmacopoeia 9th edition. The specific preparation method depends on the dosage form.

[0042] The active ingredient and pharmaceutically acceptable excipients in the "pharmaceutical formulation" described in this invention will vary depending on the identity, body type, and / or condition of the treated subject and further on the route of administration of the active ingredient. The pharmaceutical formulation may contain between 0.1% and 100% (w / w) of the active ingredient.

[0043] As used herein, “treatment” means, unless otherwise stated, reversing or alleviating the condition or disease to which the term applies, or one or more symptoms of such condition or disease, inhibiting the progression of said condition or disease or one or more symptoms thereof, or preventing said condition or disease or one or more symptoms thereof. As used in this invention, the term “treatment” refers to a therapeutic act, as defined above.

[0044] This invention does not limit the source of the raw materials used. Unless otherwise specified, all raw materials used in this invention are commercially available products commonly used in this technical field. Unless otherwise specified, all percentages are mass percentages, all temperatures are room temperature (10-35℃), and all solvents are ultrapure water. Specifically, the buffer solution formula is: 40 mL of ultrapure water containing 5.48 g sucrose, 0.30 g potassium chloride, 0.17 g disodium hydrogen phosphate, and 0.11 g potassium dihydrogen phosphate.

[0045] The preparation method of chloroplast extract is as follows: Take 500g of fresh spinach, wash it thoroughly and remove the veins. Use a stirrer to initially crush the spinach, add 10mL of buffer solution, transfer it to a mortar and grind it into a paste. Then, filter the crude chloroplast extract using vacuum filtration with three layers of gauze as a buffer. Centrifuge the crude chloroplast extract at 4℃ and 1500rpm for 2min and collect the supernatant. Repeat twice. Then, centrifuge the supernatant at 4℃ and 3000rpm for 5min and collect the supernatant to obtain pure chloroplasts. Resuspend the chloroplasts in 3mL of buffer solution for later use.

[0046] Example 1: Polydopamine-encapsulated chloroplast nanomaterials (PDA@Chloroplast) A schematic diagram of the PDA@Chloroplast preparation method of this invention is shown below. Figure 1 As shown, sodium alginate was added to the chloroplast extract, followed by dopamine, and then sodium hydroxide was added dropwise. In the solution, dopamine and sodium alginate formed polydopamine under the catalysis of hydrogen peroxide. Polydopamine then assembled with chloroplasts in a self-assembly manner to obtain the product PDA@Chloroplast.

[0047] Example 1-1 2.5 mL of a 400 μg / mL sodium alginate solution was mixed with 2 mL of a 3 mg / mL chloroplast extract, followed by 1 mL of a 200 μg / mL dopamine solution. Then, 0.5 mL of a 0.1 mol / L sodium hydroxide solution was slowly added dropwise to initiate the polymerization reaction. The reaction system was placed in a shaker at 4 °C for 3 h to complete mixing and reaction, yielding the product PDA@Chloroplast. The obtained product was pure and free of precipitate.

[0048] Examples 1-2 2.5 mL of a 200 μg / mL sodium alginate solution was mixed with 2 mL of a 1 mg / mL chloroplast extract, followed by 1 mL of a 100 μg / mL dopamine solution. Then, 0.5 mL of a 0.1 mol / L sodium hydroxide solution was slowly added dropwise. The reaction system was placed in a shaker at 4 °C for 3 h to complete mixing and reaction, yielding the product PDA@Chloroplast. The obtained product was pure and free of precipitate.

[0049] Comparative Example 1-1 2.5 mL of sodium alginate solution with a concentration of 400 μg / mL was mixed with 2 mL of chloroplast extract with a concentration of 1.5 mg / mL, followed by 1 mL of dopamine solution with a concentration of 200 μg / mL. Then, 0.5 mL of sodium hydroxide solution with a concentration of 0.3 mol / L was slowly added dropwise. The reaction system was placed in a shaker at 4 °C for 3 h to complete mixing and reaction, yielding the product PDA@Chloroplast. A precipitate was formed in the obtained product.

[0050] Comparative Examples 1-2 2.5 mL of a 100 μg / mL sodium alginate solution was mixed with 2 mL of a 0.5 mg / mL chloroplast extract, followed by 1 mL of a 50 μg / mL dopamine solution. Then, 0.5 mL of a 0.05 mol / L sodium hydroxide solution was slowly added dropwise. The reaction system was placed in a shaker at 4 °C for 3 h to complete mixing and reaction, yielding the product PDA@Chloroplast. The resulting product was incompletely reacted, pure, and without precipitate.

[0051] Example 2: Morphology and stability of polydopamine-encapsulated chloroplast nanomaterials (PDA@Chloroplast) Figure 2 SEM images A and B show that the self-assembled nanocoating successfully encapsulates chloroplasts to form PDA@Chloroplast. Figure 2 The Zeta potential analysis results of PDA@Chloroplast showed that the Zeta potential value was -12.8 mV, indicating that the material has good stability in aqueous media.

[0052] The results in summary indicate that PDA@Chloroplast possesses good structure and stability, which is beneficial for biomedical applications.

[0053] Example 3: In vitro antioxidant test of polydopamine-encapsulated chloroplast nanomaterials (PDA@Chloroplast) ABTS is a commonly used free radical and is frequently used to evaluate the free radical scavenging ability of nanomaterials. This invention delves into the scavenging efficacy of PDA@Chloroplast against ABTS free radicals. To more comprehensively evaluate its antioxidant potential, this invention also focuses on reactive oxygen species (ROS)—specifically O2—which are crucial in physiological and pathological environments. •- The study systematically investigated the scavenging efficacy of PDA@Chloroplast against three representative free radicals, namely •OH radicals, and its inhibitory effect on superoxide dismutase (SOD). Results are as follows: Figure 3 As shown.

[0054] Experimental results show that PDA@Chloroplast can effectively scavenge ABTS and O2 in a concentration-dependent manner. - It inhibits •OH free radicals, and SOD has a good inhibitory effect. Specifically, as the concentration of PDA@Chloroplast increased from 0.25 mg / mL to 1 mg / mL, the elimination rate of ABTS rapidly increased from 27% to 65% (e.g., Figure 3 (As shown in Figure A). Similarly, when the concentration of PDA@Chloroplast reached 1 mg / mL, the scavenging rate of •OH radicals also reached 71%, showing a significant concentration dependence (e.g., ...). Figure 3 As shown in Figure B). PDA@Chloroplast for superoxide anions (O2) - Free radicals also showed good scavenging effects, with a scavenging rate of up to 37% at a concentration of 0.1 mg / mL (e.g., Figure 3 (As shown in C). Furthermore, PDA@Chloroplast increased the inhibition rate of superoxide dismutase (SOD), achieving an inhibition rate of up to 68% at a concentration of 0.4 mg / mL (as shown in Figure C). Figure 3 (As shown in D). These results fully demonstrate that PDA@Chloroplast possesses excellent and rapid free radical scavenging capabilities.

[0055] Meanwhile, this invention employs electron spin resonance (ESR) technology to further verify the antioxidant properties of PDA@Chloroplast, with results as follows: Figure 3 As shown.

[0056] The results showed that the ESR signal peak of DPPH• was significantly reduced in the presence of PDA@Chloroplast, which directly reflects the efficient scavenging ability of PDA@Chloroplast for DPPH• (e.g., Figure 3 As shown in Figure E, with the addition of PDA@Chloroplast, the peak intensity of the hydroxyl radical •OH adduct in the ESR spectrum also decreased, indicating that the •OH adduct was effectively consumed (as shown in Figure E). Figure 3 (As shown in F). Similarly, under the action of PDA@Chloroplast, O2 •- The ESR signal peak also showed a significant decrease, further confirming the effect of PDA@Chloroplast on O2. •- Excellent clearance ability (such as) Figure 3 (As shown in G).

[0057] In summary, these findings consistently confirm that PDA@Chloroplast exhibits excellent multi-antioxidant properties against a variety of free radicals in vitro.

[0058] Meanwhile, in vitro antioxidant tests revealed that the PDA@Chloroplasts prepared in Examples 1-1 and 1-2 exhibited excellent antioxidant and free radical scavenging abilities, which were essentially the same. In contrast, the PDA@Chloroplasts prepared in Comparative Examples 1-1 and 1-2 showed poorer antioxidant and free radical scavenging abilities, especially at a concentration of 0.4 mg / mL, where the superoxide dismutase (SOD) inhibition rate did not exceed 30%.

[0059] Example 4: Protective effect of polydopamine-encapsulated chloroplast nanomaterials (PDA@Chloroplast) on DSS-induced inflammatory bowel disease. 1. The alleviating effect of DSS on enteritis induced in mice This invention constructed a DSS-induced mouse enteritis model and investigated the therapeutic effect of PDA@Chloroplast on DSS-induced enteritis. The results are as follows: Figure 4 As shown.

[0060] like Figure 4 As shown in Figure A, the weight loss trend induced by colitis in mice treated with PDA@Chloroplast was significantly alleviated, indicating that PDA@Chloroplast helps maintain stable weight in mice and reduces weight loss caused by enteritis. Figure 4As shown in Figure B, the DAI score in the DSS group increased significantly over time, indicating a continuous worsening of enteritis symptoms. In contrast, the DAI score remained stable or even showed a downward trend after PDA@Chloroplast treatment, demonstrating that PDA@Chloroplast effectively alleviates enteritis-related symptoms. Colon length is a crucial indicator for enteritis detection, primarily used to assess intestinal health and the severity of enteritis. During the progression of enteritis, the colon length in the model group mice significantly shortened. Therefore, colon length was measured in each group of mice to assess the degree of enteritis damage. Figure 4 As shown in C and D, compared with the blank control group (control group), the colon length of mice in the DSS group (model group) was significantly shortened. Quantitative analysis of colon length further confirmed this result, indicating that DSS successfully induced severe intestinal damage. Conversely, compared with the DSS group, mice in the treatment group treated with PDA@Chloroplast showed significant recovery of colon length. This result indicates that PDA@Chloroplast can effectively improve DSS-induced abnormal colon length in mice, thereby alleviating enteritis.

[0061] 2. Histopathological observation results This invention includes histopathological evaluation to further explore the protective effect of PDA@Chloroplast on the gut, such as... Figure 5 As shown.

[0062] H&E staining revealed that the colonic tissue structure in the blank control group (control group) remained intact, with no obvious damage. In contrast, the DSS group (model group) showed significant pathological changes in the colonic tissue, including disordered and destroyed glandular structures, epithelial cell damage, and extensive inflammatory cell infiltration, indicating that DSS successfully induced enteritis and caused severe intestinal tissue damage. However, after PDA@Chloroplast treatment, the colonic tissue morphology in the treatment group was significantly improved compared to the DSS group, with more orderly glandular arrangement, improved epithelial cell integrity, and reduced inflammatory cell infiltration, suggesting that PDA@Chloroplast can alleviate DSS-induced colonic tissue damage.

[0063] Next, changes in mucus secretion were detected using AB-PSA staining, with blue indicating acidic mucus and purplish-red indicating neutral mucus. The results showed abundant blue-purple mucus in the blank control group (control group), indicating sufficient colonic mucus secretion in normal mice. Conversely, the mucus staining in the DSS group (model group) was significantly lighter, indicating a substantial reduction in colonic mucus secretion and damage to the intestinal protective barrier after DSS-induced enteritis. Compared to the DSS group, the blue-purple signal of mucus staining in the treatment group after PDA@Chloroplast treatment was enhanced, indicating that PDA@Chloroplast can promote colonic mucus secretion and help repair the intestinal mucus barrier.

[0064] In summary, PDA@Chloroplast demonstrated a significant protective effect in the DSS-induced inflammatory bowel disease model, effectively reducing colonic tissue damage and repairing the intestinal mucus barrier.

[0065] 3. Detection of intestinal barrier function This invention investigates the effects of PDA@Chloroplast on the expression of tight junction proteins (ZO-1, Occludin, and E-Cadherin) in intestinal epithelial cells of DSS-induced enteritis mice using immunofluorescence staining, and further evaluates the effect of PDA@Chloroplast on intestinal barrier function detection, such as... Figure 6 As shown.

[0066] The results showed that the green fluorescence of the three proteins was significantly reduced in the DSS group (model group), indicating that after DSS-induced enteritis, the tight junctions of intestinal epithelial cells were disrupted, the expression of tight junction proteins was reduced, and the intestinal barrier function was impaired. In contrast, after PDA@Chloroplast administration, the green fluorescence intensity and distribution of ZO-1, Occludin, and E-Cadherin in the treatment group were significantly better than those in the DSS group and closer to those in the blank control group, suggesting that PDA@Chloroplast can promote the expression of tight junction proteins in intestinal epithelial cells and improve DSS-induced intestinal barrier damage.

[0067] Example 5: Polydopamine-encapsulated chloroplast nanomaterials (PDA@Chloroplast) modulate the in vivo immune microenvironment to inhibit DSS-induced intestinal inflammation. 1. Immunofluorescence staining results This invention labeled the macrophage phenotype using CD86 (a marker of M1 macrophages) and CD206 (a marker of M2 macrophages) for immunofluorescence staining to evaluate the anti-inflammatory ability of PDA@Chloroplast. The results are as follows: Figure 7 As shown.

[0068] like Figure 7 As shown, compared to the blank control group, the model group exhibited bright fluorescence of CD86 and weak fluorescence of CD206 under DSS treatment, indicating that macrophages tended towards M1 polarization. In contrast, after PDA@Chloroplast treatment, the fluorescence signal of CD86 decreased as the fluorescence signal of CD206 increased, confirming that PDA@Chloroplast promoted the conversion of macrophages from the M1 to the M2 phenotype. These results indicate that PDA@Chloroplast can effectively improve the inflammatory pathological state.

[0069] 2. Detection of expression levels of inflammatory factors in the gut like Figure 8 The results showed that, at the mRNA level, compared with the blank control group (NC), DSS significantly increased the expression of IL-1β, L-6, TNF-α, and Nlrp3, while PDA@Chloroplast significantly reduced the level of pro-inflammatory cytokines in the gut.

[0070] In addition, DSS treatment leads to intestinal... NRF2 and Keap1 The levels of these two anti-inflammatory factors were significantly lower than those in the blank control group (NC). However, after PDA@Chloroplast treatment, the expression levels of these anti-inflammatory factors showed a significant rebound. These results indicate that PDA@Chloroplast can effectively regulate the inflammatory response, potentially playing a positive role in improving intestinal inflammation by inhibiting the expression of pro-inflammatory factors and promoting the production of anti-inflammatory factors.

[0071] 3. Immunoflow cytometry results This invention involves euthanizing mice treated with PDA@Chloroplast, extracting spleen cells, and performing immune cell analysis using flow cytometry to study the in vivo immune effect. The results are as follows: Figure 9 As shown.

[0072] like Figure 9 As shown in the AD diagram, a shift in macrophage polarization from M1 to M2 was observed in the spleen of mice treated with PDA@Chloroplast. Quantitative analysis of M1 and M2 further confirmed this result. Comparison of splenic dendritic cells (DCs) across different groups revealed a lower proportion of mature DCs in the PDA@Chloroplast group (e.g., ...). Figure 9 (As shown in the middle EF). This indicates that PDA@Chloroplast can inhibit the maturation of DC cells, placing them in an immature state of immune tolerance, thereby affecting their antigen presentation function and regulating the initiation of the immune response. These immune-tolerant DC cells are called tolerant DC cells (tDCs), and tolerant DC cells can suppress excessive immune activation in DSS mice. PDA@Chloroplast can also reduce T cell activation and proliferation, especially pro-inflammatory Th17 cells, by reducing CD80 and CD11C expression and decreasing T cell co-stimulatory signals. This helps control excessive immune responses (such as...). Figure 9 (As shown in GL). Furthermore, PDA@Chloroplast can also inhibit the expression of Gr1 and NKP46, further regulating the immune response (e.g., ...). Figure 9 (As shown in MN).

[0073] In summary, PDA@Chloroplast can modulate the inflammatory immune response in DSS-treated mice, promote the formation of specific immune tolerance, and thus promote effective specific immune tolerance.

[0074] The above description, in conjunction with specific embodiments, further illustrates the present invention. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions to the details and form of the technical solutions of the present invention can be made without departing from the spirit and scope of the invention, and all such modifications and substitutions fall within the protection scope of the present invention.

Claims

1. A method for preparing a polydopamine encapsulated chloroplast nanomaterial, characterized in that, The method comprises the following steps: (1) mixing sodium alginate solution and chloroplast extract solution to obtain a mixed solution; (2) adding dopamine solution and alkali solution into the mixed solution to perform polymerization reaction, and obtaining the product.

2. The production method according to claim 1, characterized by, The concentration of the sodium alginate solution in step (1) is 200-400 μg / mL. The concentration of the chloroplast extract solution in step (1) is 1-3 mg / mL.

3. The production method according to claim 1, characterized by, The mass ratio of chloroplasts to sodium alginate in the mixed solution in step (1) is 3-10:

1.

4. The production method according to claim 3, characterized by, The mass ratio of chloroplasts to sodium alginate in the mixed solution in step (1) is 4-6:

1.

5. The preparation method according to claim 1, characterized in that, The concentration of the dopamine solution in step (2) is 100-300 μg / mL. The concentration of the alkali solution in step (2) is 0.1-0.4 mol / L.

6. The method of claim 1, wherein, The alkali in step (2) is at least one of sodium hydroxide and potassium hydroxide.

7. The preparation method according to claim 1, characterized in that, The polymerization reaction in step (2) is performed at 2-6 ℃ for 1-5 h.

8. The polydopamine-coated chloroplast nanomaterial prepared by the preparation method in any one of claims 1-7.

9. A pharmaceutical preparation comprising polydopamine-coated chloroplast nanomaterials, characterized in that, The polydopamine-coated chloroplast nanomaterial in claim 8 and pharmaceutically acceptable adjuvants are prepared.

10. The use of the polydopamine encapsulated chloroplast nanomaterial prepared by the method of any one of claims 1-7 in the preparation of a medicament, characterized in that, The drug has at least one of the following effects: (1) antioxidant; (2) anti-inflammatory; (3) treating enteritis; (4) repairing intestinal barrier.

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