Natural antibacterial polydopamine microcapsules and methods of making the same
The natural antibacterial polydopamine microcapsules prepared by the soft template method solve the problem of easy volatility of Artemisia argyi oil, and improve stability and antibacterial efficacy, making them suitable for food packaging and antibacterial textiles.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI UNIV
- Filing Date
- 2022-12-06
- Publication Date
- 2026-06-02
AI Technical Summary
Artemisia argyi oil, as a natural antibacterial agent, is volatile and unstable when applied, which limits its use in air, light, and heat.
Natural antibacterial polydopamine microcapsules were prepared using a soft template method. DMDES was hydrolyzed and condensed to form a PDMS emulsion, and polydopamine shell material was formed on the surface of Artemisia argyi oil through the self-polymerization reaction of dopamine under alkaline aerobic conditions, thus avoiding the use of surfactants and preparing closed microcapsules.
It improves the stability and antibacterial efficacy of Artemisia argyi oil, achieves sustained release of Artemisia argyi oil, overcomes the defect of easy volatility, and has good monodispersity and environmental friendliness.
Smart Images
Figure CN115920794B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of antibacterial and microcapsule technologies, and more specifically, to a natural antibacterial polydopamine microcapsule and its preparation method. Background Technology
[0002] Natural antibacterial agents are substances with complex structures extracted from animals and plants in nature or produced by microbial metabolism. Due to their strong antibacterial properties and safety, natural antibacterial agents are widely used in food packaging, antibacterial textiles, and other fields. Among them, plant-based natural antibacterial agents are widely available, low in cost, have both edible and medicinal value, and are prepared using mature technologies, exhibiting significant antibacterial effects. Essential oils extracted from aromatic and medicinal plants through methods such as steam distillation or solvent extraction possess biological activity and exhibit antibacterial and antioxidant properties, making them suitable as plant-derived natural antibacterial agents. Examples include artemisia oil, clove oil, thyme oil, cinnamon oil, rosemary oil, and vanillin, all of which have significant inhibitory effects on bacteria.
[0003] Artemisia oil is the main medicinal component of Artemisia argyi. It is a natural antibacterial agent with broad-spectrum antibacterial activity, high efficacy, and no toxicity, offering excellent health benefits to the human body. It is generally a colorless to pale yellow liquid with a strong Artemisia argyi aroma. Its main components consist of ethers, alcohols, ketones, monoterpenes, and sesquiterpenes. Artemisia oil possesses pharmacological effects such as antibacterial and antiviral properties, anti-inflammatory and analgesic effects, hemostasis and anticoagulation, antioxidant properties, and anticancer properties, and it has a significant inhibitory effect on Bacillus anthracis. However, Artemisia oil is extremely unstable under air, light, and heat, which greatly limits its application in practical production and daily life.
[0004] Microencapsulation technology offers a promising solution for the application of volatile oils such as Artemisia argyi oil. For example, Chinese invention patent CN201510247830.9 proposes a method for preparing polydopamine aromatic microcapsules by emulsifying aromatic essential oils with surfactants. The resulting microcapsules exhibit good biocompatibility and enable the sustained release of essential oils. Microencapsulation involves encapsulating a sensitive core material, regardless of its hydrophilicity, hydrophobicity, or solid-liquid-gas state, into a closed polymer material to form tiny capsules. These capsules provide sustained release, antioxidant protection, environmental isolation, and core material protection. Microcapsules possess excellent chemical and physical stability, enabling the sustained release of essential oils.
[0005] Polydopamine is a natural polymer inspired by marine mussels, possessing many unique properties such as adhesion, hydrophilicity, UV resistance, and biodegradability. When used as a microcapsule wall material, it readily deposits onto the core material surface with excellent thickness control and good biocompatibility, making it an ideal wall material for natural essential oil sustained-release systems. Currently, polydopamine capsules are widely used in the delivery of pharmaceuticals, fertilizers, and pesticides.
[0006] The soft template method uses water-in-oil polydimethylsiloxane (PDMS) emulsion droplets obtained by hydrolysis and condensation of dimethyldiethoxysilane (DMDES) as a raw material, which serve as the core material template. These droplets are easy to remove and, compared to classic emulsions stabilized with surfactants, exhibit small particle size, monodispersity, and high stability. Furthermore, by not using surfactants, it avoids the environmental pollution and cost issues associated with surfactant recycling. Currently, there are no reports on the application of the soft template method in the preparation of natural antibacterial polydopamine microcapsules containing Artemisia argyi oil. Summary of the Invention
[0007] To address the limitations of existing technologies in the application of Artemisia argyi oil as a natural antibacterial agent, namely its volatility and insensitivity to heat, this invention aims to overcome these shortcomings by providing a natural antibacterial polydopamine microcapsule and its preparation method. The microcapsules are prepared using a soft template method involving DMDES hydrolysis and condensation, eliminating the need for surfactant removal and thus being environmentally friendly. The polydopamine shell material protects the Artemisia argyi oil from direct contact with the environment, while also enhancing adhesion, facilitating subsequent utilization and processing.
[0008] To achieve the above objectives, the present invention adopts the following technical solution:
[0009] A natural antibacterial polydopamine microcapsule, wherein the core material of the microcapsule is Artemisia argyi oil and the shell material is polydopamine, wherein Artemisia argyi oil is loaded into the polydopamine microcapsule, transforming the Artemisia argyi oil from an oily liquid into a solid powder form; the natural antibacterial microcapsule is spherical, with a particle size ranging from 0.5 to 2 micrometers. In this invention, the core material of the natural antibacterial polydopamine microcapsule is Artemisia argyi oil, and the shell material is polydopamine.
[0010] Furthermore, the natural antibacterial agent is Artemisia argyi oil.
[0011] Furthermore, an emulsion was prepared using a soft template method with DMDES hydrolysis and condensation. Dopamine undergoes a self-polymerization reaction under alkaline and aerobic conditions, and in-situ polymerization was carried out on the surface of the core material to obtain the natural antibacterial polydopamine microcapsules.
[0012] Furthermore, the average size of the natural antibacterial polydopamine microcapsule particles is 1 μm.
[0013] This invention provides a method for preparing natural antibacterial polydopamine microcapsules, the steps of which are as follows:
[0014] 1) DMDES is catalytically hydrolyzed and condensed in ammonia water of a certain concentration to form PDMS silicone oil droplets. After emulsification for a certain time, Artemisia argyi oil is added and ultrasonically injected to obtain an emulsion with solubilized Artemisia argyi oil.
[0015] 2) Add dopamine hydrochloride to Tris-HCl buffer and prepare natural antibacterial polydopamine microcapsules by in-situ self-polymerization on the surface of emulsion droplets;
[0016] 3) Post-processing is performed to obtain the natural antibacterial polydopamine microcapsule product.
[0017] Furthermore, in step 1), the oil phase of the emulsion is a mixture of silane emulsion and Artemisia argyi oil, with DMDES comprising 1.5%-3.0% by volume; ammonia comprising 1.5%-3.0% by volume; and Artemisia argyi oil comprising 2.5%-7.5% by volume.
[0018] Furthermore, in step 1), the volume fractions of DMDES and ammonia are 2.0%, 2.5%, and 3.0%, respectively.
[0019] Furthermore, in step 1), the volume percentages of Artemisia argyi oil are 2.5%, 5.0%, and 7.5%, respectively.
[0020] Furthermore, in step 1), the artemisia oil is replaced with similar essential oils such as eucalyptol, thymol, and terpene alcohol.
[0021] Further, in step 1), the method for preparing the DMDES emulsion of solubilized Artemisia argyi oil is as follows: DMDES is uniformly mixed with ammonia water, a certain amount of deionized water is added, and the mixture is shaken by hand for one minute. The mixture is then allowed to stand at 25°C for 6 hours, a certain amount of Artemisia argyi oil is added, and the mixture is gently shaken and sonicated to obtain a uniformly dispersed PDMS emulsion of solubilized Artemisia argyi oil.
[0022] Furthermore, in step 2), when carrying out the in-situ self-polymerization reaction of dopamine, the temperature of the polymerization reaction is controlled at 10-30℃, the magnetic stirring rate is 600-1200 r / min, and the reaction time is 12-36 h.
[0023] Furthermore, in step 2), the aqueous phase for in-situ polymerization is a Tris-HCl buffer with a pH of 8.0-9.5, and the concentration of dopamine hydrochloride in the Tris-HCl buffer is 1.0-3.0 mg / mL.
[0024] Furthermore, in step 3), the post-processing method uses a centrifuge to separate the microcapsules from the mixed reaction solution, washes them with deionized water at least 3 times, and freeze-dries them with liquid nitrogen for 24 hours to obtain a black powder, which is the Artemisia argyi oil natural antibacterial polydopamine microcapsule product.
[0025] Furthermore, in step 3), the post-processing method uses 0.45μm polytetrafluoroethylene filter paper to filter and separate the microcapsules from the mixed reaction solution. The microcapsules are washed with deionized water at least three times and then freeze-dried with liquid nitrogen for 24 hours to obtain a black powder, which is the Artemisia argyi oil natural antibacterial polydopamine microcapsule product.
[0026] Furthermore, in step 3), the encapsulation rate of the prepared natural antibacterial polydopamine microcapsule product is not less than 20% of the total mass of the microcapsules. The method of the present invention has a certain encapsulation rate for Artemisia argyi oil.
[0027] Compared with the prior art, the present invention has the following obvious and prominent substantive features and significant advantages:
[0028] 1. This invention microencapsulates Artemisia argyi oil, which can effectively solve the application defects of Artemisia argyi oil, such as easy volatility and insensitivity to heat.
[0029] 2. This invention uses a soft template method to prepare microcapsules, resulting in good emulsion stability and monodispersity. The preparation method is simple, does not require the removal of emulsifiers, and is environmentally friendly.
[0030] 3. This invention utilizes dopamine hydrochloride to undergo a self-polymerization reaction under alkaline and aerobic conditions to form microcapsule wall materials. It does not require the addition of monomers, initiators, etc., does not require sealing or heating, does not use organic solvents, and does not generate harmful substances. The simple process and materials used are more in line with green and environmentally friendly requirements. Attached Figure Description
[0031] Figure 1 The images show scanning electron microscope (SEM) images of the natural antibacterial polydopamine microcapsules according to Examples 1, 2, 3, and 4. In the figures, a, b, c, and d are SEM images of the natural antibacterial polydopamine microcapsules according to Examples 1, 2, 3, and 4, respectively.
[0032] Figure 2 The thermogravimetric curves of the natural antibacterial polydopamine microcapsules according to Example 3 are shown. In the figure, the black curve represents polydopamine, the red curve represents Artemisia argyi oil, and the blue curve represents the thermogravimetric curves of the natural antibacterial polydopamine microcapsules of Example 3. Detailed Implementation
[0033] The technical solution of this application will be clearly and completely described below with reference to the embodiments thereof, but the scope of protection of this invention is not limited to the following embodiments. Unless otherwise specified, the reagents and raw materials used can be purchased commercially. Experimental methods in the following embodiments that do not specify specific conditions are performed according to conventional methods and conditions, or according to the product instructions.
[0034] The above solution will be further described below with reference to specific embodiments. The preferred embodiments of the present invention are described in detail below:
[0035] This invention provides a natural antibacterial polydopamine microcapsule and its preparation method, comprising the following steps:
[0036] Example 1
[0037] In this embodiment, a natural antibacterial polydopamine microcapsule is provided. The core material of the natural antibacterial polydopamine microcapsule is Artemisia argyi oil, and the shell material is polydopamine. Artemisia argyi oil is loaded into the shell material of the sustained-release antibacterial microcapsule, which transforms the Artemisia argyi oil from an oily liquid into a solid powder. The natural antibacterial polydopamine microcapsule is spherical, and the particle size is in the range of 1-5 micrometers.
[0038] In this embodiment, the preparation method of the natural antibacterial polydopamine microcapsules includes the following steps:
[0039] Step 1: DMDES is hydrolyzed and condensed to form PDMS silicone oil droplets. After emulsification for a certain period of time, Artemisia argyi oil is added to obtain an emulsion.
[0040] Measure 0.225 mL of DMDES and 0.225 mL of ammonia water into 10 mL centrifuge tubes, add deionized water to 9 mL, shake by hand for one minute to mix evenly, and set aside as the oil phase of the silane emulsion; let stand at 25 °C for 6 hours to allow DMDES to hydrolyze and condense under the catalysis of ammonia water to obtain the PDMS emulsion; add 0.3 mL of Artemisia argyi oil to the prepared emulsion, shake gently and sonicate to obtain a uniformly dispersed PDMS emulsion with solubilized Artemisia argyi oil;
[0041] Step 2: In-situ self-polymerization of dopamine on the emulsion surface:
[0042] Prepare 36 mL of 2.5 mg / mL dopamine solution quickly and add it to a 150 mL beaker; add the prepared silane emulsion to the dopamine solution, turn on magnetic stirring, and maintain the temperature at 25 °C for 24 hours at a magnetic stirring speed of 800 rpm.
[0043] Step 3: Post-processing:
[0044] The reaction solution was centrifuged at 4000 rpm for 5 minutes to separate the polydopamine microcapsules. The product was washed with deionized water, and the washing and centrifugation were repeated three times. The obtained microcapsules were then treated with liquid nitrogen and freeze-dried for 24 hours to obtain the natural antibacterial polydopamine microcapsule product of this embodiment. See scanning electron microscopy image below. Figure 1 Illustration b in the text.
[0045] Example 2
[0046] In this embodiment, the preparation method of the natural antibacterial polydopamine microcapsules includes the following steps:
[0047] Step 1: DMDES is hydrolyzed and condensed to form PDMS silicone oil droplets. After emulsification for a certain period of time, Artemisia argyi oil is added to obtain an emulsion.
[0048] Measure 0.225 mL of DMDES and 0.225 mL of ammonia water into 10 mL centrifuge tubes, add deionized water to 9 mL, shake by hand for one minute to mix evenly, and set aside as the oil phase of the silane emulsion; let stand at 25 °C for 6 hours to allow DMDES to hydrolyze and condense under the catalysis of ammonia water to obtain the PDMS emulsion; add 0.45 mL of Artemisia argyi oil to the prepared emulsion, shake gently and sonicate to obtain a uniformly dispersed PDMS emulsion with solubilized Artemisia argyi oil;
[0049] Step 2: In-situ self-polymerization of dopamine on the emulsion surface:
[0050] Prepare 36 mL of 2.5 mg / mL dopamine solution quickly and add it to a 150 mL beaker; add the prepared silane emulsion to the dopamine solution, turn on magnetic stirring, and maintain the temperature at 25 °C for 24 hours at a magnetic stirring speed of 800 rpm.
[0051] Step 3: Post-processing:
[0052] The reaction solution was centrifuged at 4000 rpm for 5 minutes to separate the polydopamine microcapsules. The product was washed with deionized water, and the washing and centrifugation were repeated three times. The obtained microcapsules were then treated with liquid nitrogen and freeze-dried for 24 hours to obtain the natural antibacterial polydopamine microcapsule product of this embodiment. See scanning electron microscopy image below. Figure 1 Illustration c in the text.
[0053] Example 3
[0054] In this embodiment, the preparation method of the natural antibacterial polydopamine microcapsules includes the following steps:
[0055] Step 1: DMDES is hydrolyzed and condensed to form PDMS silicone oil droplets. After emulsification for a certain period of time, Artemisia argyi oil is added to obtain an emulsion.
[0056] Measure 0.225 mL of DMDES and 0.225 mL of ammonia water into 10 mL centrifuge tubes, add deionized water to 9 mL, shake by hand for one minute to mix evenly, and set aside as the oil phase of the silane emulsion; let stand at 25 °C for 6 hours to allow DMDES to hydrolyze and condense under the catalysis of ammonia water to obtain PDMS emulsion; add 0.6 mL of Artemisia argyi oil to the prepared emulsion, shake gently and sonicate to obtain a uniformly dispersed PDMS emulsion with solubilized Artemisia argyi oil;
[0057] Step 2: In-situ self-polymerization of dopamine on the emulsion surface:
[0058] Prepare 36 mL of 2.5 mg / mL dopamine solution quickly and add it to a 150 mL beaker; add the prepared silane emulsion to the dopamine solution, turn on magnetic stirring, and maintain the temperature at 25 °C for 24 hours at a magnetic stirring speed of 800 rpm.
[0059] Step 3: Post-processing:
[0060] The reaction solution was centrifuged at 4000 rpm for 5 minutes to separate the polydopamine microcapsules. The product was washed with deionized water, and the washing and centrifugation were repeated three times. The obtained microcapsules were then treated with liquid nitrogen and freeze-dried for 24 hours to obtain the natural antibacterial polydopamine microcapsule product of this embodiment. See scanning electron microscopy image below. Figure 1 Illustration d in the text.
[0061] Example 4
[0062] In this embodiment, a Japanese HITACHI scanning electron microscope was used to observe the natural antibacterial polydopamine microcapsules of Examples 1, 2, and 3, as well as the polydopamine microcapsules without Artemisia argyi oil, at 10kx magnification. The scanning electron microscope images are shown below. Figure 1 As shown in Figures a, b, c, and d, are scanning electron microscope (SEM) images of polydopamine microcapsules without Artemisia argyi oil, and Examples 1, 2, and 3, respectively. The SEM images show that all examples successfully synthesized microcapsules with a closed, complete shell structure, exhibiting a spherical shape with dimensions ranging from 0.5 to 2 micrometers. Comparison revealed that without Artemisia argyi oil, the microcapsules had a single depression on their surface; Examples 2, 3, and 4 added 0.3 mL, 0.45 mL, and 0.6 mL of Artemisia argyi oil, respectively. The microcapsules of Example 2 had a smooth surface and slightly smaller particle size; Example 3 had microcapsules with the optimal morphology, a smooth surface, and good monodispersity; the microcapsules of Example 4 exhibited heterogeneity and decreased monodispersity. The obtained natural antibacterial polydopamine microcapsules were subjected to thermogravimetric analysis, and the results are as follows: Figure 2 As shown
[0063] Example 5
[0064] In this embodiment, the thermal stability of the natural antibacterial polydopamine microcapsules of Example 3 was tested using a thermogravimetric analyzer (Q550) from TA Instruments, Inc. The difference between the thermogravimetric region of the TGA curve and that of the pure PDA microcapsules was observed, and the encapsulation efficiency of the natural antibacterial polydopamine microcapsules could be calculated. The thermogravimetric curve is shown below. Figure 2 As shown, the encapsulation rate of the natural antibacterial polydopamine microcapsules is 21.5%. The decomposition temperature of Artemisia argyi oil has increased from 0-180℃ to 300-490℃, indicating a significant improvement in thermal stability.
[0065] Example 6
[0066] This embodiment relates to determining the antibacterial effect of the natural antibacterial polydopamine microcapsules of Example 2.
[0067] Step 1: Prepare LB liquid culture medium:
[0068] Prepare 200ml LB liquid culture medium with 2g tryptone, 1g yeast extract, 2g sodium chloride, and 200mL ultrapure water. Adjust the pH to 7.0 with 1mol / L sodium hydroxide solution. After dispensing, autoclave at 121℃ for 20min and set aside for use.
[0069] Step 2: Activation of the test strain and preparation of the bacterial suspension:
[0070] First, activate the preserved bacterial culture at 37°C for 24 hours; the steps are as follows:
[0071] Two loops of bacterial cells were picked from the slant of various bacterial cells preserved at low temperature and inoculated into the corresponding liquid culture medium. The culture was carried out at 37°C and 120 r / min for 24 h with constant temperature shaking to obtain an activated bacterial suspension.
[0072] Step 3: Antibacterial test:
[0073] Accurately weigh 50 mg, 75 mg, and 100 mg of the sample from Example 2 into test tubes, sterilize under UV light for 15 min, and set aside. Transfer 0.10 ml of bacterial suspension and 9.9 ml of liquid culture medium to a test tube containing natural antibacterial polydopamine microcapsules, and incubate at 37°C and 120 rpm for 24 h with constant temperature shaking. Simultaneously, take 9.9 ml of liquid culture medium and 0.1 ml of bacterial suspension without the addition of natural antibacterial polydopamine microcapsules and incubate separately as a reference sample. Measure the absorbance of the liquid culture medium and calculate the inhibition rate. The results are shown in Table 1. See Table 1.
[0074] Table 1. Comparison of antibacterial rates of natural antibacterial polydopamine microcapsules in Example 3
[0075]
[0076] The data in Table 1 show that the natural antibacterial polydopamine microcapsules have certain antibacterial effects against both Escherichia coli and Staphylococcus aureus. At a concentration of 10 mg / mL, the inhibition rate against Staphylococcus aureus reached 20.4%, and the inhibition rate against Escherichia coli reached 15.8%.
[0077] In summary, the above embodiments describe natural antibacterial polydopamine microcapsules and their preparation method. The shell material of the natural antibacterial polydopamine microcapsules is polydopamine, and the core material is Artemisia argyi oil. Using a soft template method with dimethyldiethoxysilane (DMDES) as the raw material, dopamine is in-situ self-polymerized on the surface of polydimethylsiloxane (PDMS) emulsion droplets solubilized with Artemisia argyi oil, thus preparing natural antibacterial polydopamine microcapsules encapsulating Artemisia argyi oil. The shell material, polydopamine, has good adhesion and biocompatibility, while the core material, Artemisia argyi oil, is a naturally derived volatile oily substance with broad-spectrum antibacterial properties. The microcapsules prepared by this invention are micrometer-sized, monodisperse, and have high sphericity, with an average size of 1 μm; they exhibit high encapsulation efficiency for Artemisia argyi oil, with the highest encapsulation efficiency reaching 21.5% of the total mass of the microcapsules.
[0078] The above embodiments utilize a soft template method to prepare microcapsules, overcoming the drawbacks of classic emulsions such as high cost and environmental pollution caused by the extensive use of surfactants. The preparation process is simple. The resulting natural antibacterial polydopamine microcapsules overcome the volatility and instability of Artemisia argyi oil; they exhibit good monodispersity and a certain antibacterial efficacy; furthermore, through the sustained release of Artemisia argyi oil, they possess the potential for long-lasting antibacterial effects. The preparation of monodisperse natural antibacterial polydopamine microcapsules has broad application potential in the industrial production of aromatic microcapsules.
[0079] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made according to the purpose of the invention. Any changes, modifications, substitutions, combinations or simplifications made based on the spirit and principle of the technical solution of the present invention shall be equivalent substitutions. As long as they meet the purpose of the invention and do not deviate from the technical principle and inventive concept of the present invention, they shall fall within the protection scope of the present invention.
Claims
1. A method for preparing natural antibacterial polydopamine microcapsules, characterized in that, Includes the following steps: 1) DMDES is catalytically hydrolyzed and condensed in ammonia water of a certain concentration to form PDMS silane emulsion. After emulsification for a certain time, Artemisia argyi oil is added and ultrasonically injected to obtain an emulsion with solubilized Artemisia argyi oil. 2) Add dopamine hydrochloride to Tris-HCl buffer to prepare natural antibacterial polydopamine microcapsules by in-situ self-polymerization on the surface of emulsion droplets; 3) Post-processing is performed to obtain the natural antibacterial polydopamine microcapsule product; In step 1), the PDMS silane emulsion is prepared by catalytically hydrolyzing and condensing DMDES in ammonia water of a certain concentration, shaking by hand for one minute and standing at 25°C for 6 hours to obtain a uniformly dispersed PDMS silane emulsion. In step 2), during in-situ self-polymerization on the surface of the emulsion droplets, the temperature of the polymerization reaction is controlled at 10-30℃, the magnetic stirring rate is 600-1200 r / min, and the reaction time is 12-36 h. In step 3), the post-processing method is to use a centrifuge to separate the microcapsules from the mixed reaction solution, wash them with deionized water at least 3 times, and freeze-dry them with liquid nitrogen for 24 hours to obtain a black powder, which is the Artemisia argyi oil natural antibacterial polydopamine microcapsule product.
2. The method for preparing the natural antibacterial polydopamine microcapsules according to claim 1, characterized in that: In step 1), the oil phase of the emulsion is a mixture of PDMS silane emulsion and Artemisia argyi oil, with the volume percentage of DMDES being 1.5%-3.0%; the volume percentage of ammonia water is 1.5%-3.0%, and the volume percentage of Artemisia argyi oil is 2.5%-7.5%. Alternatively, in step 1), the volumes of DMDES are 0.135 mL, 0.18 mL, 0.225 mL, and 0.27 mL, respectively. The volumes of ammonia water were 0.135 mL, 0.18 mL, 0.225 mL, and 0.27 mL, respectively; the volumes of mugwort oil were 0.3 mL, 0.45 mL, and 0.6 mL, respectively.
3. The method for preparing the natural antibacterial polydopamine microcapsules according to claim 1, characterized in that: In step 1), the mugwort oil is replaced with different natural essential oils, such as eucalyptol, thymol, terpene alcohol, etc.
4. The method for preparing the natural antibacterial polydopamine microcapsules according to claim 1, characterized in that: In step 2), the pH of the Tris-HCl buffer is 8.0-9.5, and the concentration of dopamine hydrochloride in the Tris-HCl buffer is 1.0-3.0 mg / mL.
5. A natural antibacterial polydopamine microcapsule, characterized in that: The microcapsules are prepared by the method described in any one of claims 1 to 4, wherein the core material of the microcapsules is Artemisia argyi oil and the shell material is polydopamine. Artemisia argyi oil is loaded into the shell material of the sustained-release antibacterial microcapsules, thereby changing the form of Artemisia argyi oil from an oily liquid to a solid powder. The microcapsules are spherical with particle sizes ranging from 0.5 to 2 micrometers.
6. The natural antibacterial polydopamine microcapsules according to claim 5, characterized in that: The shell material of the sustained-release antibacterial microcapsules is polydopamine.
7. The natural antibacterial polydopamine microcapsules according to claim 5, characterized in that: Using a soft template method, dopamine was in situ self-polymerized on the surface of polydimethylsiloxane (PDMS) emulsion droplets solubilized with Artemisia argyi oil to prepare natural antibacterial polydopamine microcapsules encapsulating Artemisia argyi oil.