Shape-tunable mesoporous metal-polyphenol nanoparticles, methods of making and using the same

Abstract

The present application relates to a kind of adjustable mesoporous metal-polyphenol nanoparticles and its preparation method and application.The nanoparticle preparation method includes the following steps: (1) the preparation of polyphenol;(2) the preparation of mesoporous metal-polyphenol nanoparticles, by adjusting the amount of metal compound can be controlled particle size, by adjusting the amount of ethanol and deionized water can be controlled structure, by adjusting reaction time can be controlled pore size.Compared with prior art, the present application can control the morphology of metal-polyphenol nanoparticles by simply adjusting the reaction conditions, and the prepared mesoporous metal-polyphenol nanoparticles have excellent antioxidant activity and various enzyme activities, and the complex structure can realize the loading of active substances and synergistic antioxidant.

Description

Technical Field

[0001] This invention relates to the field of metal polyphenol materials technology, and in particular to a morphology-tunable mesoporous metal-polyphenol nanoparticle, its preparation method, and its application. Background Technology

[0002] Metal-polyphenol networks, as a multifunctional material, are widely used for the encapsulation and delivery of active substances. Polyphenols are widely found in various plants in nature, containing abundant phenolic hydroxyl groups, and possess excellent adhesion, antibacterial, antioxidant, anti-inflammatory, and anticancer properties. The polyhydroxyl structure of polyphenols allows them to form pH-dependent dynamic coordination bonds with various metals, forming supramolecular network structures. Because polyphenols retain a large number of phenolic hydroxyl groups after coordination complexation with metals, they still exhibit good adhesion, antibacterial, and antioxidant properties. Simultaneously, metal-polyphenol networks also possess good biocompatibility, high mechanical strength, and pH-responsive disassembly characteristics. Currently, metal-polyphenol networks have been applied in the fragrance emulsion field, where a metal-polyphenol network film is in situ coated onto the surface of the fragrance emulsion to form a capsule. The physical encapsulation and antioxidant properties of the capsule shell effectively solve the problem of poor chemical stability in easily oxidized fragrances. However, existing metal-polyphenol network structures are not dense and have thin shells, making them prone to collapse and leading to core material leakage.

[0003] Therefore, there is an urgent need to develop a metal-polyphenol nanoparticle with high loading rate, stable structure, and tunable morphology for use in fragrance encapsulation and other fields. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art by providing a morphology-tunable mesoporous metal-polyphenol nanoparticle, its preparation method and application. The obtained mesoporous metal-polyphenol nanoparticle has a high loading rate and stable structure, which can improve the antioxidant properties of fragrances.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] This invention provides a method for preparing mesoporous metal-polyphenol nanoparticles with tunable morphology, comprising the following steps:

[0007] S1. First, add poloxamer 407 to ethanol and deionized water, then add ammonia water, stir to dissolve, then add tannic acid (TA) and formaldehyde, stir to obtain polytannic acid (pTA) dispersion.

[0008] S2. First, add poloxamer 407 to ethanol and stir to dissolve. Then add the pTA dispersion obtained in S1 and m-trimethylbenzene, sonicate, then add the aqueous solution of the metal compound, stir, centrifuge and wash, and vacuum dry to obtain mesoporous metal-polyphenol (meso-pTA-MPN) nanoparticles.

[0009] The particle size of the mesoporous metal-polyphenol nanoparticles can be adjusted by the amount of metal compound used in S2, wherein the molar ratio of tannic acid to metal compound is 1:(1~11).

[0010] The pore size of the mesoporous metal-polyphenol nanoparticles can be adjusted by the stirring time in S2, wherein the stirring time is 5s to 24h.

[0011] The structure of the mesoporous metal-polyphenol nanoparticles can be adjusted by the amount of ethanol and deionized water used, wherein the volume ratio of ethanol to deionized water is 1:1 or 1:(1.47-4). The ethanol is the sum of the volumes of ethanol in the pTA dispersion obtained in S1 and the ethanol added in S2, and the deionized water is the volume of deionized water in the pTA dispersion obtained in S1.

[0012] Furthermore, when the volume ratio of ethanol to deionized water is 1:1, the structure of the mesoporous metal-polyphenol nanoparticles is a solid structure.

[0013] Furthermore, when the volume ratio of ethanol to deionized water is 1:(1.47-4), the structure of the mesoporous metal-polyphenol nanoparticles can be controlled to be a hollow shell structure with a hollow interior and a solid outer shell.

[0014] Under low ethanol concentration conditions, metal and polyphenols undergo transitional growth on the surface of TMB oil droplets, self-assembling via the Frank-Vander Merwe model to form a hollow shell structure. Under high ethanol concentration conditions, the metal and polyphenols self-assemble individually in the aqueous phase via an interfacial separation model, forming a solid structure. The hollow shell structure of the mesoporous metal-polyphenol nanoparticles exists only when the volume ratio of ethanol to deionized water is 1:(1.47–4), while the solid structure is the mesoporous metal-polyphenol nanoparticle commonly found in this invention.

[0015] Furthermore, in S1, the mass ratio of poloxamer 407, ammonia, TA and formaldehyde is 1:(1-4):1:(1-4).

[0016] Furthermore, in S1, the stirring time is 12 to 36 hours.

[0017] Furthermore, in S2, the mass ratio of poloxamer 407, TA, m-trimethylbenzene, and the metal compound is 1:(0.01-0.4):(1-5):(0.1-0.4).

[0018] Furthermore, in S2, the metal compound is any one of ferric chloride hexahydrate, anhydrous copper sulfate, and cobalt nitrate hexahydrate; the solvent for centrifugal washing is ethanol and deionized water; and the vacuum drying temperature is 50–70°C.

[0019] Furthermore, in S2, the power of the ultrasound is 200W, and the duration of the ultrasound is 2 minutes.

[0020] Furthermore, in S1 and S2, the stirring method is magnetic stirring, and the rotation speed is 400-600 rpm.

[0021] The present invention also provides a morphology-tunable mesoporous metal-polyphenol nanoparticle with a particle size of 144.50–480.22 nm and a pore size of 2.33–12.56 nm.

[0022] The present invention also provides an application of morphology-tunable mesoporous metal-polyphenol nanoparticles, which can be used to load fragrances, wherein the fragrances are citral, cinnamaldehyde or eugenol.

[0023] The specific fragrance loading process is as follows: first, poloxamer 407 is added to ethanol, then the polytannic acid dispersion obtained from S1 is added in sequence, as well as citral or cinnamaldehyde or eugenol, and aqueous solution of metal compounds. After stirring, centrifugation, washing, and vacuum drying, mesoporous metal-polyphenol nanoparticles loaded with different fragrances are obtained.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) This invention uses formaldehyde prepolymerized tannic acid to increase the molecular weight of tannic acid, thereby preparing mesoporous metal-polyphenol nanoparticles with stable structure, high loading rate and tunable morphology, which solves the problem of unstable and easy collapse of traditional metal-polyphenol network structure.

[0026] (2) By adjusting the molar ratio of metal and polyphenol, this invention can be used to prepare mesoporous metal-polyphenol nanoparticles with different particle sizes.

[0027] (3) The present invention uses meta-trimethylbenzene as a pore-expanding agent. Compared with traditional metal-polyphenol nanoparticles, mesoporous metal-polyphenol nanoparticles with larger surface pore size can be obtained. Moreover, the pore size of the particles can be controlled by simply adjusting the reaction time.

[0028] (4) The present invention can precisely control the shape of mesoporous metal-polyphenol nanoparticles by simply adjusting the reaction system, and can obtain a hollow shell structure with a hollow interior and a solid outer shell.

[0029] (5) This invention prepares mesoporous metal-polyphenol nanoparticles loaded with fragrance in one step, achieving dual protection of fragrance at both the physical and chemical levels, and effectively solving the problem of poor chemical stability of easily oxidized fragrances. Attached Figure Description

[0030] Figure 1 This is a scanning electron microscope image of the meso-pTA-MPN nanoparticles prepared in Example 1;

[0031] Figure 2 Transmission electron microscopy image of meso-pTA-MPN nanoparticles prepared in Example 1;

[0032] Figure 3 The UV spectra of pTA, ferric chloride, and meso-pTA-MPN shown in Example 1 are as follows;

[0033] Figure 4 The image shows a scanning electron microscope (SEM) image of the meso-pTA-MPN nanoparticles prepared in Example 2.

[0034] Figure 5 The image shows a scanning electron microscope (SEM) image of the meso-pTA-MPN nanoparticles prepared in Example 3.

[0035] Figure 6 Scanning electron microscope (SEM) images of meso-pTA-MPN nanoparticles prepared with different amounts of metals in Example 4;

[0036] Figure 7 The image shown is a scanning electron microscope image of the hollow shell type meso-pTA-MPN as shown in Example 5.

[0037] Figure 8 The image shown is a transmission electron microscope (TEM) image of the hollow shell type meso-pTA-MPN as shown in Example 5.

[0038] Figure 9 The images shown are scanning electron microscope (SEM) images of meso-pTA-MPN with different mesopore sizes as shown in Example 6.

[0039] Figure 10 The image shows a scanning electron microscope (SEM) image of meso-pTA-MPN nanoparticles loaded with different fragrances, as shown in Example 7.

[0040] Figure 11 The ABTS removal effect of meso-pTA-MPN shown in Example 8. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Any preparation methods, materials, structures, or compositional ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0042] All reactions in all embodiments of the present invention were carried out at room temperature.

[0043] Example 1

[0044] A method for preparing mesoporous metal-polyphenol nanoparticles with tunable morphology includes the following steps:

[0045] Preparation of S1 and pTA dispersion:

[0046] Weigh 0.20 g of poloxamer 407 and add it to a mixed solution of 5.00 mL ethanol and 25.00 mL deionized water. Stir thoroughly to dissolve. Use a pipette to add 0.5 mL of ammonia water to the above solution and stir for 1 h. Weigh 0.20 g of tannic acid and add it to the above solution. Stir thoroughly to dissolve. Use a pipette to add 0.40 mL of formaldehyde solution to the above solution and stir for 24 h to obtain a pTA dispersion.

[0047] Preparation of S2, meso-pTA-MPN nanoparticles:

[0048] Weigh 1.00 g of poloxamer 407 and add it to 20.00 mL of ethanol. Stir thoroughly to dissolve. Add the pTA dispersion obtained in S1 to the above solution and stir thoroughly. Use a pipette to add 1.20 mL of m-trimethylbenzene to the above solution and sonicate at 200 W for 2 minutes using an ultrasonic cell disruptor to obtain a composite micelle emulsion. Weigh 0.10 g of ferric chloride hexahydrate and add it to 2.00 mL of deionized water to prepare a ferric chloride aqueous solution. Add the ferric chloride aqueous solution to the above composite micelle emulsion and stir for 24 h. After the reaction is complete, wash the solution twice with 50% ethanol solution and once with deionized water. Dry under vacuum at 50 °C for 12 h to obtain meso-pTA-MPN nanoparticles.

[0049] The meso-pTA-MPN nanoparticles prepared in Example 1 were characterized by scanning electron microscopy, such as... Figure 1 As shown in the figure, the average particle size of the meso-pTA-MPN nanoparticles is 347.60 nm, and the scale bar in the figure is 200 nm.

[0050] The meso-pTA-MPN nanoparticles prepared in Example 1 were characterized by transmission electron microscopy, such as... Figure 2 As shown in the figure, the scale bar is 200nm.

[0051] Figure 3The UV spectrum of pTA, ferric chloride, meso-pTA-MPN shows a distinct LMCT band in the wavelength range of 400–600 nm, which proves the coordination of iron ions with polyphenols.

[0052] Example 2

[0053] A method for preparing mesoporous metal-polyphenol nanoparticles with tunable morphology includes the following steps:

[0054] Preparation of S1 and pTA dispersion:

[0055] Weigh 0.20 g of poloxamer 407 and add it to a mixed solution of 5.00 mL ethanol and 25.00 mL deionized water. Stir thoroughly to dissolve. Use a pipette to add 0.5 mL of ammonia water to the above solution and stir for 1 h. Weigh 0.20 g of tannic acid and add it to the above solution. Stir thoroughly to dissolve. Use a pipette to add 0.40 mL of formaldehyde solution to the above solution and stir for 24 h to obtain a pTA dispersion.

[0056] Preparation of S2, meso-pTA-MPN nanoparticles:

[0057] Weigh 1.00 g of poloxamer 407 and add it to 20.00 mL of ethanol. Stir thoroughly to dissolve. Add the pTA dispersion obtained in S1 to the above solution and stir thoroughly. Use a pipette to add 1.20 mL of m-trimethylbenzene to the above solution and sonicate at 200 W for 2 minutes using an ultrasonic cell disruptor to obtain a composite micelle emulsion. Weigh 0.10 g of anhydrous copper sulfate and add it to 2.00 mL of deionized water to prepare a copper sulfate aqueous solution. Add the copper sulfate aqueous solution to the above composite micelle emulsion and stir for 24 h. After the reaction is complete, wash the solution twice with 50% ethanol solution and once with deionized water. Dry under vacuum at 50 °C for 12 h to obtain meso-pTA-MPN nanoparticles.

[0058] The meso-pTA-MPN nanoparticles prepared in Example 2 were characterized by scanning electron microscopy, such as... Figure 4 As shown in the figure, the average particle size of the meso-pTA-MPN nanoparticles is 242.65 nm, and the scale bar in the figure is 200 nm.

[0059] Example 3

[0060] A method for preparing mesoporous metal-polyphenol nanoparticles with tunable morphology includes the following steps:

[0061] Preparation of S1 and pTA dispersion:

[0062] Weigh 0.20 g of poloxamer 407 and add it to a mixed solution of 5.00 mL ethanol and 25.00 mL deionized water. Stir thoroughly to dissolve. Use a pipette to add 0.5 mL of ammonia water to the above solution and stir for 1 h. Weigh 0.20 g of tannic acid and add it to the above solution. Stir thoroughly to dissolve. Use a pipette to add 0.40 mL of formaldehyde solution to the above solution and stir for 24 h to obtain a pTA dispersion.

[0063] Preparation of S2, meso-pTA-MPN nanoparticles:

[0064] Weigh 1.00 g of poloxamer 407 and add it to 20.00 mL of ethanol. Stir thoroughly to dissolve. Add the pTA dispersion obtained in S1 to the above solution and stir thoroughly. Use a pipette to add 1.20 mL of m-trimethylbenzene to the above solution and sonicate at 200 W for 2 minutes using an ultrasonic cell disruptor to obtain a composite micelle emulsion. Weigh 0.10 g of cobalt nitrate hexahydrate and add it to 2.00 mL of deionized water to prepare a cobalt nitrate aqueous solution. Add the cobalt nitrate aqueous solution to the above composite micelle emulsion and stir for 24 h. After the reaction is complete, wash the solution twice with 50% ethanol solution and once with deionized water. Dry under vacuum at 50 °C for 12 h to obtain meso-pTA-MPN nanoparticles.

[0065] The meso-pTA-MPN nanoparticles prepared in Example 3 were characterized by scanning electron microscopy, such as... Figure 5 As shown in the figure, the average particle size of the meso-pTA-MPN nanoparticles is 349.15 nm, and the scale bar in the figure is 200 nm.

[0066] Example 4

[0067] By adjusting the amount of ferric chloride hexahydrate used, meso-pTA-MPN nanoparticles of different particle sizes can be obtained.

[0068] Preparation of S1 and pTA dispersion:

[0069] Weigh 0.20 g of poloxamer 407 and add it to a mixed solution of 5.00 mL ethanol and 25.00 mL deionized water. Stir thoroughly to dissolve. Use a pipette to add 0.5 mL of ammonia water to the above solution and stir for 1 h. Weigh 0.20 g of tannic acid and add it to the above solution. Stir thoroughly to dissolve. Use a pipette to add 0.40 mL of formaldehyde solution to the above solution and stir for 24 h to obtain a pTA dispersion.

[0070] Preparation of S2, meso-pTA-MPN nanoparticles:

[0071] Weigh 1.00 g of poloxamer 407 and add it to 20.00 mL of ethanol. Stir thoroughly to dissolve. Add the pTA dispersion obtained in S1 to the above solution and stir thoroughly. Use a pipette to add 1.20 mL of m-trimethylbenzene to the above solution and sonicate at 200 W for 2 minutes using an ultrasonic cell disruptor to obtain a composite micelle emulsion. Weigh 0.03, 0.10, 0.15, 0.21, 0.27, and 0.33 g of ferric chloride hexahydrate and add them to 2.00 mL of deionized water to prepare ferric chloride aqueous solution. Add the ferric chloride aqueous solution to the above composite micelle emulsion and stir for 24 h. After the reaction is complete, wash the solution twice with 50% ethanol solution and once with deionized water. Dry under vacuum at 50 °C for 12 h to obtain meso-pTA-MPN nanoparticles of different particle sizes.

[0072] The meso-pTA-MPN nanoparticles prepared in Example 4 were characterized by scanning electron microscopy, such as... Figure 6 As shown in the figure, the particle size of the meso-pTA-MPN nanoparticles can be controlled within the range of 144.50 to 480.22 nm. The scale bar in the figure is 200 nm. Figure 1 shows meso-pTA-MPN nanoparticles with a particle size of 144.50 nm obtained by adding 0.03 g of ferric chloride hexahydrate; Figure 2 shows meso-pTA-MPN nanoparticles with a particle size of 209.74 nm obtained by adding 0.10 g of ferric chloride hexahydrate; Figure 3 shows meso-pTA-MPN nanoparticles with a particle size of 251.89 nm obtained by adding 0.15 g of ferric chloride hexahydrate; Figure 4 shows meso-pTA-MPN nanoparticles with a particle size of 313.24 nm obtained by adding 0.21 g of ferric chloride hexahydrate; Figure 5 shows meso-pTA-MPN nanoparticles with a particle size of 347.6 nm obtained by adding 0.27 g of ferric chloride hexahydrate; and Figure 6 shows meso-pTA-MPN nanoparticles with a particle size of 480.22 nm obtained by adding 0.33 g of ferric chloride hexahydrate.

[0073] Example 5

[0074] By adjusting the amounts of ethanol and deionized water used, meso-pTA-MPN with different structures can be obtained.

[0075] Preparation of S1 and pTA dispersion:

[0076] Weigh 0.20 g of poloxamer 407 and add it to a mixed solution of 5.00 mL ethanol and 25.00 mL deionized water. Stir thoroughly to dissolve. Use a pipette to add 0.5 mL of ammonia water to the above solution and stir for 1 h. Weigh 0.20 g of tannic acid and add it to the above solution. Stir thoroughly to dissolve. Use a pipette to add 0.40 mL of formaldehyde solution to the above solution and stir for 24 h to obtain a pTA dispersion.

[0077] Preparation of S21, meso-pTA-MPN nanoparticles:

[0078] Weigh 0.50 g of poloxamer 407 and add it to 1.25 mL of ethanol. Stir thoroughly to dissolve. Add the pTA dispersion obtained in S1 to the above solution and stir thoroughly. Use a pipette to add 0.50 mL of m-trimethylbenzene to the above solution and sonicate at 200 W for 2 minutes using an ultrasonic cell disruptor to obtain a composite micelle emulsion. Weigh 0.10 g of ferric chloride hexahydrate and add it to 2.00 mL of deionized water to prepare a ferric chloride aqueous solution. Add the ferric chloride aqueous solution to the above composite micelle emulsion and stir for 24 h. After the reaction is complete, wash the solution twice with 50% ethanol solution and once with deionized water. Dry under vacuum at 50 °C for 12 h to obtain meso-pTA-MPN nanoparticles.

[0079] Preparation of S22, meso-pTA-MPN nanoparticles:

[0080] Weigh 1.00 g of poloxamer 407 and add it to 12.00 mL of ethanol. Stir thoroughly to dissolve. Add the pTA dispersion obtained in S1 to the above solution and stir thoroughly. Use a pipette to add 1.00 mL of m-trimethylbenzene to the above solution and sonicate at 200 W for 2 minutes using an ultrasonic cell disruptor to obtain a composite micelle emulsion. Weigh 0.10 g of ferric chloride hexahydrate and add it to 2.00 mL of deionized water to prepare a ferric chloride aqueous solution. Add the ferric chloride aqueous solution to the above composite micelle emulsion and stir for 24 h. After the reaction is complete, wash the solution twice with 50% ethanol solution and once with deionized water. Dry under vacuum at 50 °C for 12 h to obtain meso-pTA-MPN nanoparticles.

[0081] The meso-pTA-MPN nanoparticles prepared in Example 5 were characterized by scanning electron microscopy and transmission electron microscopy, as shown in the figure. Figure 7 and 8 The meso-pTA-MPN nanoparticles in the figure are hollow-shell particles with an average particle size of 388.67±40.31 nm and a scale bar of 200 nm.

[0082] Example 6

[0083] By adjusting the stirring time in S2, meso-pTA-MPN nanoparticles with different pore sizes can be obtained.

[0084] Preparation of S1 and pTA dispersion:

[0085] Weigh 0.20 g of poloxamer 407 and add it to a mixed solution of 5.00 mL ethanol and 25.00 mL deionized water. Stir thoroughly to dissolve. Use a pipette to add 0.5 mL of ammonia water to the above solution and stir for 1 h. Weigh 0.20 g of tannic acid and add it to the above solution. Stir thoroughly to dissolve. Use a pipette to add 0.40 mL of formaldehyde solution to the above solution and stir for 24 h to obtain a pTA dispersion.

[0086] Preparation of S2, meso-pTA-MPN nanoparticles:

[0087] Weigh 1.00 g of poloxamer 407 and add it to 20.00 mL of ethanol. Stir thoroughly to dissolve. Add the pTA dispersion obtained in S1 to the above solution and stir thoroughly. Use a pipette to add 2.00 mL of m-trimethylbenzene to the above solution and sonicate at 200 W for 2 minutes using an ultrasonic cell disruptor to obtain a composite micelle emulsion. Weigh 0.10 g of ferric chloride hexahydrate and add it to 2.00 mL of deionized water to prepare a ferric chloride aqueous solution. Add the ferric chloride aqueous solution to the above composite micelle emulsion and take the products obtained by stirring for 5 s, 5 min, 10 min, 30 min, and 24 h, respectively. After the reaction is complete, wash the solution twice with 50% ethanol solution and once with deionized water. Dry under vacuum at 50 °C for 12 h to obtain meso-pTA-MPN nanoparticles with different pore sizes.

[0088] The meso-pTA-MPN prepared in Example 6 was characterized by scanning electron microscopy, as shown in the figure. Figure 9 The pore size of the meso-pTA-MPN nanoparticles can be tuned within the range of 2.33–12.56 nm (scale bar in the figure is 200 nm). The average pore size of the meso-pTA-MPN nanoparticles prepared by stirring for 5 s is 8.32 nm, that prepared by stirring for 5 min is 10.94 nm, that prepared by stirring for 10 min is 11.44 nm, that prepared by stirring for 30 min is 12.56 nm, and that prepared by stirring for 24 h is 2.33 nm.

[0089] Example 7

[0090] The meso-pTA-MPN nanoparticles prepared in this embodiment can be used to load fragrances.

[0091] Preparation of S1 and pTA dispersion:

[0092] Weigh 0.20 g of poloxamer 407 and add it to a mixed solution of 5.00 mL ethanol and 25.00 mL deionized water. Stir thoroughly to dissolve. Use a pipette to add 0.5 mL of ammonia water to the above solution and stir for 1 h. Weigh 0.20 g of tannic acid and add it to the above solution. Stir thoroughly to dissolve. Use a pipette to add 0.40 mL of formaldehyde solution to the above solution and stir for 24 h to obtain a pTA dispersion.

[0093] Preparation of S2, meso-pTA-MPN nanoparticles:

[0094] Weigh 1.00 g of poloxamer 407 and add it to 20.00 mL of ethanol. Stir thoroughly to dissolve. Add the pTA dispersion obtained in S1 to the above solution and stir thoroughly. Use a pipette to add 2.00 mL of citric acid, cinnamaldehyde, and eugenol to the above solution. Use an ultrasonic cell disruptor to sonicate at 200 W for 2 minutes to obtain a composite micelle emulsion. Weigh 0.10 g of ferric chloride hexahydrate and add it to 2.00 mL of deionized water to prepare a ferric chloride aqueous solution. Add the ferric chloride aqueous solution to the above composite micelle emulsion and stir for 24 h. After the reaction is complete, wash the solution twice with 50% ethanol solution and once with deionized water. Dry under vacuum at 50 °C for 12 h to obtain meso-pTA-MPN nanoparticles loaded with different fragrances.

[0095] The meso-pTA-MPN nanoparticles prepared in Example 7 were characterized by scanning electron microscopy, as shown in Figure 10. The average particle sizes of the three fragrance-loaded meso-pTA-MPN nanoparticles were 174.49 nm, 197.31 nm, and 207.68 nm, respectively. The scale bar in the figure is 200 nm. Specifically, Figure ⅰ shows meso-pTA-MPN nanoparticles loaded with citral, with a particle size of 174.94 nm; Figure ⅱ shows meso-pTA-MPN nanoparticles loaded with cinnamaldehyde, with a particle size of 197.31 nm; and Figure ⅲ shows meso-pTA-MPN nanoparticles loaded with eugenol, with a particle size of 207.68 nm.

[0096] Example 8

[0097] In vitro experiments were conducted on the meso-pTA-MPN nanoparticles prepared by stirring for 30 minutes in Example 6 to demonstrate their good flavoring and antioxidant effects.

[0098] Meso-pTA-MPN nanoparticles were dispersed in anhydrous ethanol to form a 5.00 mg / mL dispersion. A 7.00 mM solution of 2,2-azino-bis(3-ethyl-benzothiazole-6-sulfonic acid) diammonium salt (ABTS) and a 2.45 mM solution of potassium persulfate (K₂S₂O₈) were prepared, along with a phosphate buffer solution (PBS, 10.00 mM, pH 7.40). The ABTS solution was then mixed with K₂S₂O₈. The solutions were mixed at a mass ratio of 1:3 to 7 and stored in the dark for 24 hours to serve as stock solutions. The stock solutions were then mixed with different sample solutions at mass ratios of 147:80, 147:200, and 147:400 (i.e., the concentrations of meso-pTA-MPN dispersions were 4.00 g / mL, 10.00 g / mL, and 20.00 g / mL, respectively). After incubation in the dark for 30 minutes, the mixtures were transferred to cuvettes and the absorbance was measured at 734 nm.

[0099] like Figure 11 As shown, the absorbance at 734 nm decreases continuously with the increase of sample concentration, indicating that the meso-pTA-MPN material has good antioxidant properties.

[0100] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing mesoporous metal-polyphenol nanoparticles with tunable morphology, characterized in that, Includes the following steps: S1. First, add poloxamer 407 to ethanol and deionized water, then add ammonia, stir to dissolve, then add tannic acid and formaldehyde, stir to obtain polytannic acid dispersion. S2. First, add poloxamer 407 to ethanol, then add the polytannic acid dispersion obtained in S1, as well as m-trimethylbenzene and the aqueous solution of the metal compound in sequence. Stir, centrifuge, wash and vacuum dry to obtain mesoporous metal-polyphenol nanoparticles. The particle size of the mesoporous metal-polyphenol nanoparticles can be adjusted by the amount of metal compound used in S2, wherein the molar ratio of tannic acid to metal compound is 1:(1~11). The pore size of the mesoporous metal-polyphenol nanoparticles can be adjusted by the stirring time in S2, wherein the stirring time is 5 s to 24 h. The structure of the mesoporous metal-polyphenol nanoparticles can be adjusted by the amount of ethanol and deionized water used, wherein the volume ratio of ethanol to deionized water is 1:1 or 1:(1.47~4). In S1, the mass ratio of poloxamer 407, ammonia, tannic acid and formaldehyde is 1:(1~4):1:(1~4), and the stirring time is 12~36 h. In S2, the mass ratio of poloxamer 407, tannic acid, m-trimethylbenzene, and the metal compound is 1:(0.01~0.4):(1~5):(0.1~0.4). The mesoporous metal-polyphenol nanoparticles can be controlled to form a hollow shell structure with a hollow interior and a solid outer shell, wherein the volume ratio of ethanol to deionized water is 1:(1.47~4). The mesoporous metal-polyphenol nanoparticles have a particle size of 144.50~480.22 nm and a pore size of 2.33~12.56 nm. In S2, the metal compound is any one of ferric chloride hexahydrate, anhydrous copper sulfate, and cobalt nitrate hexahydrate; When the volume ratio of ethanol to deionized water is 1:(1.47~4), the structure of the mesoporous metal-polyphenol nanoparticles can be controlled to be a hollow shell structure with a hollow interior and a solid outer shell.

2. The method for preparing morphology-tunable mesoporous metal-polyphenol nanoparticles according to claim 1, characterized in that, In S2, the solvent for centrifugal washing is ethanol and deionized water.

3. The method for preparing morphology-tunable mesoporous metal-polyphenol nanoparticles according to claim 1, characterized in that, In S2, the vacuum drying temperature is 50~70 ℃.

4. The method for preparing morphology-tunable mesoporous metal-polyphenol nanoparticles according to claim 1, characterized in that, In S1 and S2, the stirring method is magnetic stirring, and the speed is 400~600 rpm.

5. A mesoporous metal-polyphenol nanoparticle prepared by the method according to any one of claims 1 to 4, characterized in that, The mesoporous metal-polyphenol nanoparticles have a particle size of 144.50~480.22 nm and a pore size of 2.33~12.56 nm.

6. An application of the mesoporous metal-polyphenol nanoparticles as described in claim 5, characterized in that, The mesoporous metal-polyphenol nanoparticles can be used to load fragrances, which include any one of citral, cinnamaldehyde, or eugenol. The specific fragrance loading process is as follows: first, poloxamer 407 is added to ethanol, then the polytannic acid dispersion obtained from S1 is added in sequence, as well as citral or cinnamaldehyde or eugenol, and aqueous solution of metal compounds. After stirring, centrifugation, washing, and vacuum drying, mesoporous metal-polyphenol nanoparticles loaded with different fragrances are obtained.

Images