Polydopamine coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of biological materials, in particular to a polydopamine coating as well as a preparation method and application thereof. According to the specific technical scheme, a dopamine solution and a hydrogen peroxide aqueous solution are mixed on the surface of a base material to be coated, and the polydopamine coating is generated. The prepared polydopamine coating can effectively improve the lower urinary symptoms such as pathological bladder mucous membrane barrier damage, erosion, bleeding, pain, frequent urination and urgent urination, mucous membrane repair is accelerated, and the life quality of a patient is improved. The technical scheme provided by the invention has a wide application prospect in the field of chemical cystitis treatment.

Description

A polydopamine coating, its preparation method and application Technical Field

[0001] This invention relates to the field of biomaterials technology, specifically to a polydopamine coating, its preparation method, and its application. Background Technology

[0002] Chemical cystitis is caused by chemotherapy drugs such as cyclophosphamide or other irritating chemicals directly affecting the bladder mucosa, leading to mucosal barrier damage, erosion, bleeding, pain, and lower urinary symptoms such as urinary frequency and urgency. Currently, there is a lack of a repair material that can achieve rapid, uniform, and long-lasting adhesion to the bladder wall, resulting in treatment relying on frequent irrigation or extensive surgery, both of which have significant limitations. Existing treatment methods mainly include drug therapy and surgical treatment. Drug therapy includes anti-inflammatory drugs, antibiotics, and antioxidants, but their effectiveness is limited, and there are issues such as controversy and side effects. Surgical treatment carries high risks and a slow recovery.

[0003] In summary, there are currently no effective and safe products on the market for the prevention of chemical cystitis; there is an urgent need for a product that can be effectively applied to chemical cystitis, providing a barrier, lubrication, and repair effect to the affected area. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a polydopamine coating, its preparation method, and its application.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: The present invention discloses a method for preparing a polydopamine coating, wherein a dopamine solution and a hydrogen peroxide aqueous solution are mixed on the surface of the substrate to be coated, and a polydopamine coating is generated in situ.

[0006] Preferably, the reaction temperature of the dopamine solution and hydrogen peroxide water is 15-45°C, and the reaction time is 1-70 min; the volume ratio of the dopamine solution to the hydrogen peroxide water solution is 50:1-1:1.

[0007] Preferably, the concentration of the hydrogen peroxide aqueous solution is 0.01-50%.

[0008] Preferably, the preparation process of the dopamine solution is as follows: dissolve dopamine monomer in alkaline buffer solution, stir until dissolved, add catalase to obtain dopamine solution.

[0009] Preferably, the concentration of dopamine monomer in the dopamine solution is 0.5-500 mg / mL, and the concentration of catalase in the dopamine solution is 1-50 mg / mL.

[0010] Preferably, the pH of the alkaline buffer solution is 7.5-9.0.

[0011] Preferably, the substrate to be coated is biological bladder tissue.

[0012] Accordingly, a polydopamine coating is prepared by one of the preparation methods described above.

[0013] Preferably, the thickness of the polydopamine coating is 10-500 nm.

[0014] Accordingly, the application of the aforementioned polydopamine coating in the preparation of materials for chemical cystitis.

[0015] The present invention has the following beneficial effects: 1. The present invention mixes dopamine, catalase and hydrogen peroxide on the surface of the substrate to be coated, and reacts to generate a polydopamine coating. The resulting polydopamine coating can effectively relieve the symptoms of chemical cystitis and will not cause problems such as bacterial resistance.

[0016] 2. The present invention generates the polydopamine coating by in-situ polymerization at the affected area, providing a mild and effective treatment for chemical cystitis without the need for surgery, thus avoiding the risks and complications of surgery.

[0017] 3. This invention utilizes catalase to catalyze the decomposition of hydrogen peroxide to produce oxygen and H2O2. H2O2 induces leukocytes to aggregate at the wound surface, thereby recruiting immune cells and accelerating wound healing. Furthermore, the release of oxygen through hydrogen peroxide, combined with the antioxidant effect of polydopamine, can effectively improve problems such as tissue ischemia, hypoxia, and microcirculation disorders caused by the destruction of the bladder mucosal barrier, accelerate ulcer healing, and promote tissue repair.

[0018] 4. The polydopamine coating of the present invention can play a barrier role. The polydopamine coating generated by in-situ polymerization can serve as an effective bladder mucosal barrier for the treatment of chemical cystitis, further protecting the bladder mucosa, effectively inhibiting tissue damage and deterioration, and accelerating wound healing.

[0019] 5. The coating of the present invention has a flexible duration, which can be adjusted according to the patient's specific condition and the development of the disease. The duration of the coating on the bladder can be adjusted (approximately 1-15 days), and the treatment plan can be adjusted accordingly to achieve the best therapeutic effect.

[0020] 6. The reaction system for preparing polydopamine according to this invention is simple, the raw materials are readily available and safe and non-toxic, it can improve the therapeutic effect under a mild operating environment, and the price is cheaper than hyperbaric oxygen therapy, making it easy to promote and implement.

[0021] 7. The technical solution of the present invention can also be used to develop new antioxidants and cell protectants, which can be well applied in the fields of medical treatment, chemical damage treatment, biomaterials and enzyme engineering, and other multidisciplinary fields. It is expected to have a positive impact in multiple fields and promote technological progress in related fields. Attached Figure Description

[0022] Figure 1 shows the Fourier transform infrared spectra of dopamine and polydopamine; Figure 2 shows the dopamine polymerization at different time points on the surface of isolated bladder tissue (left: 5 min, right: 10 min); the black part represents polydopamine, the white part represents bladder tissue, and the scale bar is 20 mm; Figure 3 shows the preparation of the in-situ polymerized polydopamine coating on the surface of isolated bladder; the black part in the figure represents the polydopamine coating; the PBS soaking group represents normal tissue; the mild ulcer and severe ulcer treatment groups represent bladder tissue with different degrees of ulceration; Figure 4 shows the surface of isolated bladder. Scraping experiments of in-situ polymerized polydopamine coatings (from left to right: before and after glass rod scraping, and before and after metal spatula scraping); the solution in the water bath is physiological saline, and the black part is polydopamine; the PBS soaking group is normal tissue; the mild and severe ulcer treatment groups represent bladder tissue with different degrees of ulceration; Figure 5 is a frozen section photograph of bladder tissue; the left side is the overall view, and the right side is a magnified view; Figure 6 is a H&E section photograph of bladder tissue; the left side is the overall view, and the right side is a magnified view. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Unless otherwise specified, the technical means used in the implementation examples are conventional means well known to those skilled in the art.

[0025] This invention discloses a method for preparing a polydopamine coating. A dopamine solution and an aqueous hydrogen peroxide solution are mixed on the surface of a substrate to be coated. The reaction temperature is 15-45℃, and the reaction time is 1-70 min, more preferably 17-40℃ for 2-60 min; optimally 37℃ for 10 min, resulting in in-situ formation of the polydopamine coating. The substrate to be coated is biological bladder tissue. The concentration of hydrogen peroxide in the aqueous hydrogen peroxide solution is 0.01-50%, more preferably 1-10%, and even more preferably 3-8%.

[0026] The reaction principle is as follows: Furthermore, the preparation process of the dopamine solution is as follows: dopamine monomer is dissolved in an alkaline buffer solution, stirred until dissolved, and then catalase (such as HRP or CAT) is added to obtain the dopamine solution. The concentration of dopamine monomer in the dopamine solution is 0.5-500 mg / mL, more preferably 20-200 mg / mL, and the concentration of catalase in the dopamine solution is 1-50 mg / mL. The pH of the alkaline buffer solution is 7.5-9.0, more preferably 8.0-8.6, and the alkaline buffer solution is a Tris buffer solution.

[0027] In some preferred embodiments, the substrate to be coated is immersed in a dopamine solution, and an aqueous hydrogen peroxide solution is added dropwise, resulting in a polydopamine coating on the surface of the substrate. The thickness of the polydopamine coating is 10-500 nm.

[0028] This invention discloses the application of the aforementioned polydopamine coating in the preparation of materials for chemical cystitis.

[0029] The polydopamine coating disclosed in this invention can interact with the bladder mucosa to enhance the repair ability of bladder cells; at the same time, it can alleviate bladder damage caused by chemotherapy, inhibit oxidative damage to bladder tissue after chemotherapy, improve bladder barrier function, and prevent cell apoptosis and inflammatory response.

[0030] The polydopamine coating can also be loaded with functional components, such as antioxidants or anti-inflammatory drugs, as needed to enhance the protective effect of the coating.

[0031] This invention addresses the limitations of current treatments for chemical cystitis by providing an in-situ polymerized adhesive dopamine polymer coating. This coating forms a protective layer in the bladder injury area after chemotherapy, reducing inflammation and promoting tissue repair. A combination of dopamine, catalase, and hydrogen peroxide is used to form a polydopamine barrier on the bladder wall, protecting and shielding the bladder injury site after chemotherapy. The coating provided by this invention has low environmental requirements, maintaining high reactivity even at temperatures far below body temperature. It can form a polydopamine coating in situ on the bladder surface, and the pathological degree of the bladder has little impact on coating formation. The polydopamine coating prepared by this invention is universally applicable, forming on different types of bladder surfaces, suitable for various bladder tissues, with a wide range of applications and significant market demand and application value.

[0032] The present invention will be further described below with reference to specific embodiments.

[0033] The isolated bladder tissues used in the embodiments of this invention were all derived from Large White pigs. The catalase used was specifically catalase CAT. Unless otherwise specified, the solvent for all solutions involved in this invention is water; all concentrations of all solutions are mass concentrations; and all raw materials used are commercially available.

[0034] Example 1 The preparation process of polydopamine is as follows: (1) Prepare Tris buffer: Take 0.605g of Tris and add it to 45mL of PBS, stir to dissolve; adjust the pH of the solution to 8.4-8.6, and make up to 50ml.

[0035] (2) Prepare dopamine solution: Weigh 0.5g of dopamine hydrochloride and add it to 10ml of the above Tris buffer solution. Stir until dissolved. Weigh 10mg of catalase and dissolve it in the above mixture to obtain dopamine solution, which is reagent A. (3) Prepare polydopamine: Prepare 3wt% H2O2 aqueous solution, which is denoted as reagent B. Mix reagent A and reagent B in a volume ratio of 1:1 and react at 37℃. Then freeze dry and perform Fourier transform infrared spectroscopy to detect the synthesis of polydopamine.

[0036] The results are shown in Figure 1, at 1100-1250cm. -1 Within the specified range, the intensity of the phenolic CO stretching vibration peak on PDA (polydopamine) decreases. This is because some phenolic hydroxyl groups are oxidized during PDA synthesis, leading to a decrease in peak intensity on the PDA. The peak intensity is lower in the 1550-1650 cm⁻¹ range. -1 Within this range, the intensity of the NH stretching vibration peak on the PDA decreases. This is because the primary amine (-NH2) reacts with the aromatic ring, resulting in a decrease in the peak intensity on the PDA.

[0037] Example 2: The preparation method of polydopamine coating is as follows: 0.5 mL of dopamine solution (dopamine concentration of 0.5 g / 10 mL, catalase concentration of 5 mg / mL, and Tris buffer as solvent) is added dropwise to the surface of the treated isolated bladder tissue, and then 0.1 mL of 3% hydrogen peroxide is added dropwise. The reaction is carried out at 17 °C and 37 °C for 5-10 min respectively to obtain polydopamine coating.

[0038] Bladder ulcer models of different disease severity were constructed. Isolated bladder tissue was treated with acetic acid solution, and then a polydopamine coating was prepared on the surface of the isolated bladder tissue (using the method in Example 2). The stability of the coating was observed. At the same time, the bladder of the PBS-treated group was set up as a normal control group.

[0039] Figure 2 shows the dopamine polymerization on the surface of isolated bladder tissue at different time points. As can be seen from the figure, a continuous polydopamine coating was formed on the bladder surface.

[0040] Figure 3 shows the preparation of an in-situ polymerized polydopamine coating on the surface of an ex vivo bladder. The black part in the figure represents the polydopamine coating. The PBS soaking group represents normal tissue. The mild and severe ulcer treatment groups represent bladder tissue with different degrees of ulceration. As can be seen from the figure, a continuous polydopamine coating was formed on the surface of the bladder with mild and severe ulceration.

[0041] Figure 4 shows the scraping experiment of in-situ polymerized polydopamine coating on the surface of an isolated bladder. From left to right, the figures show the results before and after the glass rod scraping experiment, and before and after the metal spatula scraping experiment. The black material in the figures is polydopamine. The PBS soaking group represents normal tissue. The mild and severe ulcer treatment groups represent bladder tissue with different degrees of ulceration. As can be seen from the figure, a continuous polydopamine coating was formed on the bladder surface of the PBS soaking group, the mild ulcer treatment group, and the severe ulcer treatment group. In particular, the coating obtained under the reaction at 37°C remained stable after multiple scrapings. The coating adhered tightly to the bladder tissue, and the coating network had high stability.

[0042] Example 3 describes the preparation method of the polydopamine coating: 0.5 mL of dopamine solution (dopamine concentration of 0.5 g / 10 mL, catalase concentration of 5 mg / mL, and Tris buffer as solvent) was added dropwise to bladder ulcers of varying degrees, followed by the addition of 0.1 mL of 3% hydrogen peroxide. The reaction was carried out at 37°C for 10 min to generate the polydopamine coating. As shown in the figure, the obtained coating remained stable even after repeated scraping.

[0043] Bladder tissue was sectioned and observed (see Figures 5 and 6). Figure 5 shows frozen sections of bladder tissue; the left side is an overall view, and the right side is a magnified view. The images show that in normal tissue, after physical scraping, the mucosal layer was compressed (room temperature - light scraping, room temperature - heavy scraping, and bladder group), and the mucosa was basically translucent light gray, indicating a collagen structure. The mild ulcer group and the severe ulcer group also showed compression of the mucosal layer, and the mucosa was basically opaque bluish-gray, accompanied by bluish-gray aggregates, indicating polydopamine material. The degree of ulceration and the intensity of scraping had little effect on the presence of polydopamine. These results indicate that a large amount of polydopamine material adheres to the surface of the bladder tissue.

[0044] Figure 6 shows H&E section photographs of bladder tissue; the left side is the overall view, and the right side is a magnified view. The images show that in normal tissue, after physical scraping, the mucosal layer is compressed (room temperature - light scraping, room temperature - heavy scraping, and bladder group), and the mucosa is basically translucent red, which is a collagen structure. The mild ulcer group and the severe ulcer group also show compression of the mucosal layer, and the surface of the mucosa contains a thin layer of opaque gray material, accompanied by bluish-gray aggregates, which is polydopamine material. The degree of ulceration and the intensity of scraping have little effect on the presence of polydopamine. These results indicate that a large amount of polydopamine material adheres to the surface of bladder tissue.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a polydopamine coating, characterized in that: A polydopamine coating is generated in situ by mixing a dopamine solution and an aqueous hydrogen peroxide solution on the surface of the substrate to be coated.

2. The preparation method according to claim 1, characterized in that: The reaction temperature of the dopamine solution and hydrogen peroxide water is 15-45℃, and the reaction time is 1-70 min; the volume ratio of the dopamine solution to the hydrogen peroxide water solution is 50:1-1:

1.

3. The preparation method according to claim 1, characterized in that: The concentration of the hydrogen peroxide aqueous solution is 0.01-50%.

4. The preparation method according to claim 2, characterized in that: The preparation process of the dopamine solution is as follows: dissolve dopamine monomer in alkaline buffer solution, stir until dissolved, add catalase to obtain dopamine solution.

5. The preparation method according to claim 4, characterized in that: The concentration of dopamine monomer in the dopamine solution is 0.5-500 mg / mL, and the concentration of catalase in the dopamine solution is 1-50 mg / mL.

6. The preparation method according to claim 4, characterized in that: The pH of the alkaline buffer solution is 7.5-9.

0.

7. The preparation method according to claim 1, characterized in that: The substrate to be coated is biological bladder tissue.

8. A polydopamine coating prepared by the preparation method according to any one of claims 1-7.

9. A polydopamine coating according to claim 8, characterized in that: The thickness of the polydopamine coating is 10-500 nm.

10. The use of the polydopamine coating of claim 8 or 9 in the preparation of materials for chemical cystitis.

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