Antioxidant nano material as well as preparation method and application thereof

Abstract

The invention provides an antioxidant nano material as well as a preparation method and application thereof. The antioxidant nano material comprises the following components: polydopamine and a cerium element-polydopamine complex. The components of the anti-oxidation nano material comprise polydopamine and a cerium element-polydopamine complex, on one hand, by virtue of unique electronic properties of cerium ions and coordination of the cerium ions and the polydopamine, regulation and control of a microstructure of the polydopamine are realized, reaction sites of active oxygen are increased, a band gap is reduced, and electron transfer is promoted; on the other hand, due to redox pairs of trivalent cerium ions / tetravalent cerium ions in the antioxidant nano material, reaction active sites of the antioxidant nano material are increased, and the delocalization capability of pi electrons is accelerated, so that the reaction capability of the antioxidant nano material and active oxygen is improved; therefore, the anti-oxidation nano material has excellent anti-oxidation performance.

Description

Technical Field

[0001] This invention belongs to the field of antioxidant technology, and relates to an antioxidant nanomaterial, and more particularly to an antioxidant nanomaterial, its preparation method and application. Background Technology

[0002] Polydopamine (PDA), as an artificial melanin nanomaterial, possesses excellent photothermal conversion, anti-inflammatory, and reactive oxygen species (ROS) scavenging properties. In recent years, research on PDA-based ROS scavenging has received widespread attention. PDA is prepared from dopamine through oxidative polymerization and molecular rearrangement. Its ROS scavenging ability mainly stems from its abundant surface functional groups (such as catechol and amino groups) and conjugated electronic structure. Specifically, the catechol groups on the PDA surface exhibit redox activity; their phenolic hydroxyl groups can directly quench free radicals by donating hydrogen atoms or reduce ROS via electron transfer. Furthermore, during PDA formation, oligomers are embedded into the polymer backbone through π–π stacking and cation-π interactions. This stacking structure can regulate the in-plane electron transfer behavior of the oligomers, thereby affecting the overall antioxidant properties of the material.

[0003] However, the antioxidant properties of existing polydopamines are no longer sufficient to meet the needs of practical applications. This is mainly due to two factors: First, the oligomers in the microstructure of PDAs are often in a tightly stacked state, which restricts the delocalization ability of π electrons, thereby weakening the overall antioxidant properties of the material. Second, PDAs have structural complexity and uneven component distribution at the nanoscale, which hinders the accurate establishment of their structure-activity relationship and further performance optimization.

[0004] To improve the antioxidant properties of polydopamine, although various modifications have been attempted in the existing technology from the perspectives of synthesis pathways and reactive oxygen species reaction mechanisms, the antioxidant properties of modified PDAs are still difficult to meet the requirements of practical applications.

[0005] For example, CN113307970A discloses a method for preparing ultra-small polydopamine / polydopamine-cysteine ​​nanoparticles. By utilizing the auto-oxidation of dopamine and cysteine ​​under alkaline conditions in a sodium hydroxide system, polydopamine and polydopamine-cysteine ​​nanoparticles with a particle size of about 10 nm were successfully prepared in a one-pot method.

[0006] For example, CN113842396A discloses an antioxidant of modified polydopamine and its application, wherein the antioxidant includes: polydopamine; and manganese iron nanoparticles (PDA / MFNPs) uniformly dispersed in the polydopamine.

[0007] In summary, existing modified polydopamines suffer from limitations in antioxidant performance due to the hindered electron delocalization caused by the tight stacking of oligomers, resulting in performance that fails to meet the demands of practical applications. Therefore, developing novel polydopamine-based antioxidant nanomaterials, their preparation methods, and their applications is crucial. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide an antioxidant nanomaterial, its preparation method, and its application. The antioxidant nanomaterial comprises polydopamine and a cerium-polydopamine complex. On one hand, by utilizing the unique electronic properties of cerium ions and coordinating them with polydopamine, the microstructure of polydopamine is regulated, increasing the reaction sites for reactive oxygen species, reducing the band gap, and promoting electron transfer. On the other hand, the redox pairs of trivalent and tetravalent cerium ions present in the antioxidant nanomaterial not only increase the reactive sites but also accelerate the delocalization of π electrons, thereby enhancing the antioxidant nanomaterial's ability to react with reactive oxygen species. Therefore, the antioxidant nanomaterial exhibits excellent antioxidant properties.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides an antioxidant nanomaterial, wherein the components of the antioxidant nanomaterial include polydopamine and cerium-polydopamine complex.

[0011] The antioxidant nanomaterials provided in this invention comprise polydopamine and a cerium-polydopamine complex. On one hand, leveraging the unique electronic properties of cerium ions, a supramolecular complex is formed through the coordination of cerium ions with polydopamine, possessing a cerium ion-catechol supramolecular structure. This, in turn, regulates the internal packing of nanoparticles, achieving microstructural control of polydopamine, increasing reactive oxygen species reaction sites, reducing the band gap, and promoting electron transfer. On the other hand, the trivalent / tetravalent cerium ion redox pairs present in the antioxidant nanomaterials not only increase the reactive sites of the antioxidant nanomaterials but also lead to the incorporation of new small molecules and functional groups during dopamine polymerization. These structures disrupt the tight stacking of oligomer molecules, accelerating the delocalization of π electrons, thereby enhancing the antioxidant nanomaterials' ability to react with reactive oxygen species. Therefore, the antioxidant nanomaterials possess excellent antioxidant properties.

[0012] Preferably, the polydopamine is polymerized from dopamine.

[0013] Preferably, the cerium-polydopamine complex is formed by coordination of cerium with the phenolic hydroxyl groups in polydopamine.

[0014] Preferably, in the cerium-polydopamine complex, cerium coordinates with the phenolic hydroxyl groups in polydopamine to form a cerium ion-catechol supramolecular structure.

[0015] In this invention, the antioxidant nanomaterial may further include a cerium-dopamine complex, which is formed by coordination of cerium with the phenolic hydroxyl groups in dopamine; in the cerium-dopamine complex, cerium coordinates with the phenolic hydroxyl groups in dopamine to form a cerium ion-catechol supramolecular structure.

[0016] In this invention, cerium ion-induced dopamine polymerization can form a relatively ordered supramolecular structure (cerium ion-catechol supramolecular structure). This supramolecular structure can reduce the gap energy between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), promoting a greater degree of delocalization of π electrons, thereby improving the performance of PDAs. Simultaneously, this supramolecular structure can accelerate energy transfer, which helps quench reactive oxygen species. Furthermore, Ce... 3+ The presence of auto-oxidation causes Ce to... 3+ / Ce 4+ The presence of redox pairs, and Ce 4+ It has strong catalytic activity and generates new functional groups and small molecules during dopamine polymerization. These molecules or functional groups can disrupt the tight stacking of polymer molecules caused by electrostatic interactions, which helps to delocalize π electrons and increase the density of active sites inside the particles.

[0017] Preferably, the mass fraction of cerium in the antioxidant nanomaterial is 2.9wt% to 23.3wt%, for example, it can be 2.9wt%, 3.5wt%, 5.0wt%, 7.5wt%, 10.0wt%, 12.5wt%, 15.0wt%, 17.5wt%, 20.0wt%, 21.8wt%, or 23.3wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 8.1wt% to 23.3wt%.

[0018] Preferably, the D50 particle size of the antioxidant nanomaterial is 23nm~40nm, for example, it can be 23nm, 25nm, 28nm, 30nm, 35nm or 40nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] In a second aspect, the present invention provides a method for preparing the antioxidant nanomaterial described in the first aspect, the method comprising:

[0020] Antioxidant nanomaterials are obtained by mixing dopamine source, cerium source and solvent.

[0021] In the preparation method of antioxidant nanomaterials provided by the present invention, by mixing dopamine source, cerium source and solvent to carry out reaction, antioxidant nanomaterials with better uniformity can be obtained, thereby improving the antioxidant performance of antioxidant nanomaterials.

[0022] Preferably, the mixing includes: first mixing a dopamine source with a portion of the solvent to obtain a dopamine source solution; second mixing a cerium source with the remaining solvent to obtain a cerium source solution; and third mixing the obtained dopamine source solution and the cerium source solution to obtain a mixed solution.

[0023] Preferably, the first mixing method includes stirring until a transparent dopamine source solution is obtained.

[0024] Preferably, the second mixing method includes ultrasound until a transparent cerium source solution is obtained.

[0025] Preferably, the third mixing method includes stirring for 20 min to 50 min, for example, 20 min, 22 min, 25 min, 28 min, 30 min, 32 min, 35 min, 38 min, 40 min, 42 min, 45 min, 48 min or 50 min, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0026] Preferably, the dopamine source in the dopamine source solution includes dopamine acid salt and / or dopamine sulfate.

[0027] Preferably, the solvent in the dopamine source solution includes water.

[0028] Preferably, the concentration of dopamine source in the dopamine source solution is 0.3 mg / mL to 0.6 mg / mL, for example, it can be 0.3 mg / mL, 0.32 mg / mL, 0.35 mg / mL, 0.38 mg / mL, 0.4 mg / mL, 0.42 mg / mL, 0.45 mg / mL, 0.48 mg / mL, 0.5 mg / mL, 0.52 mg / mL, 0.55 mg / mL, 0.58 mg / mL or 0.6 mg / mL, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0029] Preferably, the cerium source in the cerium source solution includes any one or a combination of at least two of cerium nitrate, cerium chloride, cerium acetate, cerium nitrate hydrate, cerium chloride hydrate, or cerium acetate hydrate. Typical but non-limiting combinations include combinations of cerium nitrate and cerium chloride, combinations of cerium acetate and cerium nitrate hydrate, combinations of cerium chloride hydrate and cerium acetate hydrate, combinations of cerium nitrate, cerium chloride, and cerium acetate, or combinations of cerium nitrate hydrate, cerium chloride hydrate, and cerium acetate hydrate.

[0030] Preferably, the solvent in the cerium source solution includes water.

[0031] Preferably, the concentration of the cerium source in the cerium source solution is 35.0 mmol / L to 65.0 mmol / L, for example, it can be 35.0 mmol / L, 37.5 mmol / L, 40.0 mmol / L, 42.5 mmol / L, 45.0 mmol / L, 47.5 mmol / L, 50.0 mmol / L, 52.5 mmol / L, 55.0 mmol / L, 57.5 mmol / L, 60.0 mmol / L, 62.5 mmol / L or 65.0 mmol / L, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0032] Preferably, the mixing further includes the incorporation of a buffer solution.

[0033] Preferably, the buffer solution comprises a Bis-Tris solution and / or a Tris solution.

[0034] In this invention, when mixing the buffer solution, the pH of the mixed solution of dopamine source, cerium source, solvent and buffer is controlled to be 9.5~10.0, for example, it can be 9.5, 9.7, 9.9 or 10.0, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the mixing further includes, after the third mixing, a final mixing of the buffer solution and the resulting mixture.

[0036] Preferably, the final mixing method includes stirring until a precipitate with the target particle size is obtained.

[0037] In this invention, the stirring time is 15h to 30h, for example, it can be 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h or 30h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, the preparation method further includes centrifugation, washing, and drying performed sequentially after the reaction.

[0039] Thirdly, the present invention provides an application of the antioxidant nanomaterial described in the first aspect, wherein the antioxidant nanomaterial is used to scavenge reactive oxygen species.

[0040] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The antioxidant nanomaterials provided in this invention comprise polydopamine and a cerium-polydopamine complex. On one hand, leveraging the unique electronic properties of cerium ions, a supramolecular complex is formed through the coordination of cerium ions with polydopamine, possessing a cerium ion-catechol supramolecular structure. This, in turn, regulates the internal packing of nanoparticles, achieving microstructural control of polydopamine, increasing reactive oxygen species reaction sites, reducing the band gap, and promoting electron transfer. On the other hand, the trivalent / tetravalent cerium ion redox pairs present in the antioxidant nanomaterials not only increase the reactive sites of the antioxidant nanomaterials but also lead to the incorporation of new small molecules and functional groups during dopamine polymerization. These structures disrupt the tight stacking of oligomer molecules, accelerating the delocalization of π electrons, thereby enhancing the antioxidant nanomaterials' ability to react with reactive oxygen species. Therefore, the antioxidant nanomaterials possess excellent antioxidant properties. Attached Figure Description

[0043] Figure 1 This is a TEM image of the antioxidant nanomaterials provided in Example 1.

[0044] Figure 2 This is a TEM image of the antioxidant nanomaterials provided in Example 2.

[0045] Figure 3 This is a TEM image of the antioxidant nanomaterials provided in Example 3.

[0046] Figure 4 These are the absorption spectra of the antioxidant nanomaterials provided in Example 1 and Comparative Example 1.

[0047] Figure 5 This is an X-ray photoelectron absorption spectrum of cerium ions in the antioxidant nanomaterials provided in Example 1.

[0048] Figure 6 The images show the UV-Vis absorption spectra of the antioxidant nanomaterials provided in Examples 1, 1, and 2 reacting with hydrogen peroxide.

[0049] Figure 7 These are fluorescence emission spectra of the reaction between the antioxidant nanomaterials provided in Example 1, Comparative Example 1, and Comparative Example 2 and hydroxyl radicals.

[0050] Figure 8These are the UV-Vis absorption spectra of the antioxidant nanomaterials provided in Example 1, Comparative Example 1, and Comparative Example 2 reacting with superoxide negative free radicals. Detailed Implementation

[0051] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0052] Example 1

[0053] This embodiment provides an antioxidant nanomaterial, the components of which include polydopamine and cerium-polydopamine complex;

[0054] The polydopamine is polymerized from dopamine;

[0055] The cerium-polydopamine complex is formed by coordination of cerium with the phenolic hydroxyl groups in polydopamine. In the cerium-polydopamine complex, the coordination of cerium with the phenolic hydroxyl groups in polydopamine forms a cerium ion-catechol supramolecular structure.

[0056] The antioxidant nanomaterial contains 19.2 wt% cerium and has a D50 particle size of 23.3 nm.

[0057] The preparation method of the antioxidant nanomaterial includes:

[0058] (1) Mix dopamine salt salt with a portion of water solvent by stirring until a transparent dopamine salt salt solution with a concentration of 0.45 mg / mL is obtained;

[0059] (2) A transparent cerium nitrate solution with a concentration of 51.8 mmol / L was obtained by ultrasonically mixing cerium nitrate hexahydrate with the remaining aqueous solvent;

[0060] (3) The dopamine salt solution obtained in step (1) and the cerium nitrate solution obtained in step (2) are mixed by stirring for 30 minutes to obtain a mixture;

[0061] (4) The Tris solution with a concentration of 0.37 mol / L of tris(hydroxymethyl)aminomethane was mixed with the mixture obtained in step (3) and reacted until a precipitate with the target particle size was obtained. Then, the precipitate was centrifuged, washed and dried in sequence to obtain antioxidant nanomaterials.

[0062] The mass ratio of the dopamine salt in step (1) to the cerium nitrate hexahydrate in step (2) is 1.31:1.

[0063] Example 2

[0064] This embodiment provides an antioxidant nanomaterial, wherein the mass fraction of cerium in the antioxidant nanomaterial is 9.5 wt%, and the D50 particle size is 33.2 nm;

[0065] In the preparation method of the antioxidant nanomaterial, the mass ratio of dopamine salt in step (1) to cerium nitrate hexahydrate in step (2) is 3.07:1, and except for the obtained product, the rest are the same as in Example 1.

[0066] Example 3

[0067] This embodiment provides an antioxidant nanomaterial, wherein the mass fraction of cerium in the antioxidant nanomaterial is 6.7 wt%, and the D50 particle size is 35.1 nm;

[0068] In the preparation method of the antioxidant nanomaterial, the mass ratio of dopamine salt in step (1) to cerium nitrate hexahydrate in step (2) is 4.52:1, and the target particle size of the precipitate in step (4) is adjusted. All other aspects are the same as in Example 1.

[0069] Example 4

[0070] This embodiment provides an antioxidant nanomaterial, the components of which include polydopamine and cerium-polydopamine complex;

[0071] The polydopamine is polymerized from dopamine;

[0072] The cerium-polydopamine complex is formed by coordination of cerium with the phenolic hydroxyl groups in polydopamine. In the cerium-polydopamine complex, the coordination of cerium with the phenolic hydroxyl groups in polydopamine forms a cerium ion-catechol supramolecular structure.

[0073] The antioxidant nanomaterial contains 12.4 wt% cerium and has a D50 particle size of 40 nm.

[0074] The preparation method of the antioxidant nanomaterial includes:

[0075] (1) Mix dopamine salt salt with a portion of water solvent by stirring until a transparent dopamine salt salt solution with a concentration of 0.3 mg / mL is obtained;

[0076] (2) A transparent cerium chloride solution with a concentration of 65.0 mmol / L was obtained by ultrasonically mixing cerium chloride with the remaining aqueous solvent;

[0077] (3) The dopamine salt solution obtained in step (1) and the cerium chloride solution obtained in step (2) are mixed by stirring for 50 min to obtain a mixture;

[0078] (4) The Tris solution with a concentration of 0.50 mol / L of tris(hydroxymethyl)aminomethane was mixed with the mixture obtained in step (3) and reacted until a precipitate with the target particle size was obtained. Then, the precipitate was centrifuged, washed and dried in sequence to obtain antioxidant nanomaterials.

[0079] The mass ratio of the dopamine salt in step (1) to the cerium chloride in step (2) is 4:1.

[0080] Example 5

[0081] This embodiment provides an antioxidant nanomaterial, the components of which include polydopamine and cerium-polydopamine complex;

[0082] The polydopamine is polymerized from dopamine;

[0083] The cerium-polydopamine complex is formed by coordination of cerium with the phenolic hydroxyl groups in polydopamine. In the cerium-polydopamine complex, the coordination of cerium with the phenolic hydroxyl groups in polydopamine forms a cerium ion-catechol supramolecular structure.

[0084] The antioxidant nanomaterial contains 3.1 wt% cerium and has a D50 particle size of 23 nm.

[0085] The preparation method of the antioxidant nanomaterial includes:

[0086] (1) Mix dopamine sulfate with a portion of water solvent by stirring until a transparent dopamine sulfate solution with a concentration of 0.6 mg / mL is obtained;

[0087] (2) A transparent cerium acetate solution with a concentration of 35.0 mmol / L was obtained by ultrasonically mixing cerium acetate with the remaining aqueous solvent;

[0088] (3) The dopamine sulfate solution obtained in step (1) and the cerium acetate solution obtained in step (2) are mixed by stirring for 20 minutes to obtain a mixture;

[0089] (4) The Tris solution with a concentration of 0.20 mol / L of tris(hydroxymethyl)aminomethane was mixed with the mixture obtained in step (3) and reacted until a precipitate with the target particle size was obtained. Then, the precipitate was centrifuged, washed and dried in sequence to obtain antioxidant nanomaterials.

[0090] The mass ratio of dopamine sulfate in step (1) to cerium acetate in step (2) is 14:1.

[0091] Example 6

[0092] This embodiment provides an antioxidant nanomaterial, wherein the mass fraction of cerium in the antioxidant nanomaterial is 2.4 wt%.

[0093] In the preparation method of the antioxidant nanomaterial, except that the mass ratio of dopamine salt in step (1) to cerium nitrate hexahydrate in step (2) is 12.92:1, all other steps are the same as in Example 1.

[0094] Example 7

[0095] This embodiment provides an antioxidant nanomaterial, wherein the mass fraction of cerium in the antioxidant nanomaterial is 30.4 wt%.

[0096] In the preparation method of the antioxidant nanomaterial, except that the mass ratio of dopamine salt in step (1) to cerium nitrate hexahydrate in step (2) is 0.74:1, all other steps are the same as in Example 1.

[0097] Comparative Example 1

[0098] This comparative example provides an antioxidant nanomaterial, which consists only of polydopamine nanoparticles with a D50 particle size of 90 nm.

[0099] The preparation method of the antioxidant nanomaterial is as follows: 2 mL of ammonia water (mass fraction of 28wt%~30wt%) is added to 40 mL of ethanol, and then 90 mL of deionized water is added. The mixture is stirred and mixed at 30℃ to obtain a preliminary mixture. 0.5 g of dopamine hydrochloride is dissolved in 10 mL of deionized water and added dropwise to the above preliminary mixture to obtain a remixed mixture. The remixed mixture is stirred for 24 h and then centrifuged, washed three times, and the precipitate is dried and weighed to obtain polydopamine nanoparticles.

[0100] Comparative Example 2

[0101] This comparative example provides an antioxidant nanomaterial comprising only polydopamine loaded with cerium ions;

[0102] The preparation method of the antioxidant nanomaterial is as follows: 2 mL of ammonia water (mass fraction of 28%~30%) is added to 40 mL of ethanol, and then 90 mL of deionized water is added. The mixture is stirred and mixed at 30 °C to obtain a preliminary mixture. 0.5 g of dopamine hydrochloride is dissolved in 10 mL of deionized water and added dropwise to the above preliminary mixture to obtain a remixed mixture. The remixed mixture is stirred for 24 h and then centrifuged and washed three times. The precipitate is dried and weighed to obtain polydopamine nanoparticles. A polydopamine solution is then prepared with the obtained polydopamine nanoparticles, and cerium nitrate solution is added to make the mass ratio of dopamine to cerium nitrate 1.31:1. After the reaction is completed, the mixture is centrifuged and the precipitate is dried to obtain polydopamine loaded with cerium ions.

[0103] The antioxidant nanomaterials provided in Examples 1-3 were tested using transmission electron microscopy. The TEM image of the antioxidant nanomaterial provided in Example 1 is shown below. Figure 1 As shown, the TEM image of the antioxidant nanomaterial provided in Example 2 is as follows. Figure 2 As shown, the TEM image of the antioxidant nanomaterial provided in Example 3 is as follows. Figure 3 As shown.

[0104] Depend on Figure 1 It can be seen that the D50 particle size of the antioxidant nanomaterial provided in Example 1 is 23.3 nm; from Figure 2 It can be seen that the D50 particle size of the antioxidant nanomaterial provided in Example 2 is 33.2 nm; from Figure 3 It can be seen that the D50 particle size of the antioxidant nanomaterial provided in Example 2 is 35.1 nm.

[0105] The absorption spectra of the antioxidant nanomaterials provided in Example 1 and Comparative Example 1 were obtained using a UV-Vis spectrophotometer, as shown below. Figure 4 As shown; by Figure 4 As can be seen from the comparison between Example 1 and Comparative Example 1, the antioxidant nanomaterial including the polydopamine and cerium-polydopamine complex provided in Example 1 exhibits a red shift compared to the polydopamine provided in Comparative Example 1, indicating that cerium ions play a regulatory role in the microstructure of polydopamine.

[0106] The X-ray photoelectron absorption spectrum of cerium ions in the antioxidant nanomaterials provided in Example 1 was obtained using X-ray photoelectron spectroscopy (XPS), as shown below. Figure 5 As shown; by Figure 5 It is known that cerium ions exist in both trivalent and tetravalent states, indicating that cerium ions promote the polymerization of dopamine, and that Ce exists in cerium-based nanoparticles. 3+ / Ce 4+ Redox pairs.

[0107] The performance testing of the antioxidant nanomaterials provided in the above embodiments and comparative examples for degrading hydrogen peroxide was conducted using the following methods:

[0108] 1) Mix 20 μL of ethanol solution of 3,3',5,5'-tetramethylbenzidine (TMB, 5 mmol / L), 30 μL of hydrogen peroxide solution (10 mmol / L), and 760 μL of Tris (10 mmol / L, pH 4.0) aqueous solution;

[0109] 2) Transfer the above solution to a 1 mL quartz cuvette and test the UV absorbance spectrum of the mixed solution;

[0110] 3) Add 20 μL of an aqueous solution of antioxidant nanomaterials (0.11 mg / mL) to the above solution, mix the solution evenly, and then test the UV-Vis absorption spectrum of the antioxidant nanomaterials;

[0111] The maximum absorbance and absorbance at a wavelength of 660 nm of the antioxidant nanomaterials were obtained from the UV-Vis absorption spectra, as shown in Table 1; among them, the UV-Vis absorption spectrum of the ethanol solution of 3,3',5,5'-tetramethylbenzidine (corresponding to...) Figure 6 TMB), ethanol solution of 3,3',5,5'-tetramethylbenzidine (corresponding to Figure 6 The UV-Vis absorption spectra of the mixed solution obtained by mixing TMB (+H2O2) with hydrogen peroxide solution, and the UV-Vis absorption spectra of the antioxidant nanomaterials provided in Example 1 and Comparative Example 1 reacting with hydrogen peroxide are shown below. Figure 6 As shown (corresponding to TMB+H2O2+ Example 1 and TMB+H2O2+ Comparative Example 1 respectively); by Figure 6 It can be seen that the antioxidant nanomaterials provided in Example 1 have superior antioxidant properties compared to the polydopamine provided in Comparative Example 1, and can degrade hydrogen peroxide more effectively.

[0112] The performance of the antioxidant nanomaterials provided in the above embodiments and comparative examples in degrading hydroxyl radicals was tested using the following methods:

[0113] 1) Mix 1.5 mL of hydrogen peroxide (6 mmol / L) with 1.5 mL of ferrous sulfate solution (60 μmol / L) and mix for 1 hour to generate sufficient hydroxyl radicals. This mixed solution is the solution.

[0114] 2) In solution Add 50 μL of an aqueous solution of antioxidant nanomaterials (0.11 mg / mL), shake and react for 1 hour, centrifuge to remove the precipitate, and this mixture is the solution;

[0115] 3) Add 150 μL of terephthalic acid (TA, 30 mmol / L) to the solution, mix for 30 minutes, and test the fluorescence emission spectrum at 425 nm under excitation light at 350 nm.

[0116] The maximum fluorescence intensity and fluorescence intensity at a wavelength of 420 nm of the antioxidant nanomaterials were obtained through fluorescence emission spectroscopy, as shown in Table 2; Table 2 only includes the fluorescence emission spectra of terephthalic acid solutions (corresponding to...). Figure 7 The fluorescence emission spectrum of a solution containing only terephthalic acid and hydroxyl radicals (TA in the sample) Figure 7 The fluorescence emission spectra of the reaction between the antioxidant nanomaterials provided in Example 1 and hydroxyl radicals (TA+OH) are shown in Figure 1. Figure 7As shown (corresponding to TA+OH+ Example 1); by Figure 7 It can be seen that the antioxidant nanomaterials provided in Example 1 have excellent antioxidant properties and can more effectively degrade hydroxyl radicals.

[0117] The performance test of the antioxidant nanomaterials provided in the above embodiments and comparative examples for degrading superoxide negative free radicals (WST-8 reagent kit detection method) was conducted as follows:

[0118] 1) Prepare superoxide negative radicals by mixing 850 μL of detection buffer, 20 μL of xanthine solution, and 1 μL of xanthine oxidase solution. This solution is a solution for superoxide negative radicals. ;

[0119] 2) Add 12 μL of cerium-based polydopamine nanomaterials to the solution. The mixture is reacted for 30 minutes and is now a solution. ;

[0120] 3) Add 8 μL of WST-8 solution to solution ②, react for 30 minutes, centrifuge to remove nanoparticles, and obtain the UV-Vis absorption spectrum of the antioxidant nanomaterial by UV-Vis spectrophotometer.

[0121] The absorbance of the antioxidant nanomaterials at a wavelength of 460 nm was obtained by UV-Vis absorption spectroscopy, as shown in Table 3; among them, the UV-Vis absorption spectrum of the WST-8 solution (corresponding to...) Figure 8 The UV-Vis absorption spectra of the antioxidant nanomaterials (WST-8) and the reactions of the antioxidant nanomaterials provided in Example 1 and Comparative Example 1 with superoxide negative radicals are shown below. Figure 8 As shown (corresponding to WST-8+ Example 1 and WST-8+ Comparative Example 1 respectively); by Figure 8 It can be seen that the antioxidant nanomaterial provided in Example 1 has superior antioxidant properties compared with the polydopamine provided in Comparative Example 1 and the cerium-loaded polydopamine provided in Comparative Example 2, and can more effectively degrade superoxide negative free radicals.

[0122] Table 1

[0123]

[0124] Table 2

[0125]

[0126] Table 3

[0127]

[0128] From Tables 1-3, we can obtain:

[0129] (1) The antioxidant nanomaterials provided in Examples 1 to 5 have excellent antioxidant properties. They can not only degrade hydrogen peroxide more effectively, but also degrade hydroxyl radicals more effectively and superoxide negative radicals more effectively.

[0130] (2) By comparing Example 1 with Examples 6 and 7, it can be seen that in the present invention, the mass fraction of cerium in the antioxidant nanomaterial affects the antioxidant performance of the antioxidant nanomaterial; when the mass fraction of cerium in the antioxidant nanomaterial is 6.7wt%~30.0wt%, the antioxidant nanomaterial has better antioxidant performance. This is because if the cerium ion content is low, the structure of the nanoparticles is mainly a tightly stacked structure of polydopamine, which is not conducive to the delocalization of electrons and the exposure of active sites; if the cerium ion content is too high, it is not conducive to the supramolecular structure of the relatively ordered cerium ion dopamine polymer, thus affecting its antioxidant performance.

[0131] (3) As can be seen from the comparison between Example 1 and Comparative Examples 1 and 2, the antioxidant nanomaterial provided in this invention comprises polydopamine and cerium-polydopamine complex. On the one hand, by taking advantage of the unique electronic properties of cerium ions, a supramolecular complex is formed through the coordination of cerium ions and polydopamine, which has a cerium ion-catechol supramolecular structure. This regulates the internal stacking mode of the nanoparticles, realizes the regulation of the microstructure of polydopamine, increases the reaction sites of reactive oxygen species, reduces the band gap, and promotes electron transfer. On the other hand, the redox pairs of trivalent cerium ions / tetravalent cerium ions present in the antioxidant nanomaterial not only increase the reactive sites of the antioxidant nanomaterial, but also lead to the incorporation of new small molecules and functional groups during the polymerization of dopamine. These structures will destroy the tight stacking morphology between oligomer molecules, accelerate the delocalization ability of π electrons, and thus enhance the ability of the antioxidant nanomaterial to react with reactive oxygen species. Therefore, the antioxidant nanomaterial has excellent antioxidant properties.

[0132] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An antioxidant nanomaterial, characterized in that, The antioxidant nanomaterial comprises polydopamine and cerium-polydopamine complex.

2. The antioxidant nanomaterial of claim 1, wherein, The polydopamine is polymerized from dopamine.

3. The antioxidant nanomaterial of claim 1, wherein, The cerium-polydopamine complex is formed by coordination of cerium with the phenolic hydroxyl groups in polydopamine.

4. The antioxidant nanomaterial of claim 1, wherein, In the cerium-polydopamine complex, cerium ions coordinate with the phenolic hydroxyl groups in polydopamine to form a cerium ion-catechol supramolecular structure.

5. The antioxidant nanomaterial according to any one of claims 1 to 4, characterized in that, In the antioxidant nanomaterial, the mass fraction of cerium is 2.9wt%~23.3wt%.

6. The antioxidant nanomaterial according to any one of claims 1 to 4, characterized in that, The particle size of the antioxidant nanomaterial is 23nm~40nm.

7. A method for preparing the antioxidant nanomaterial according to any one of claims 1 to 6, characterized in that, The preparation method includes: Antioxidant nanomaterials are obtained by mixing dopamine source, cerium source and solvent.

8. The preparation method according to claim 7, characterized in that, The mixing process includes: first mixing a dopamine source with a portion of the solvent to obtain a dopamine source solution; second mixing a cerium source with the remaining solvent to obtain a cerium source solution; and third mixing the obtained dopamine source solution and the cerium source solution to obtain a mixed solution. Preferably, the dopamine source in the dopamine source solution includes any one or a combination of at least two of dopamine acid salt, dopamine sulfate, dopamine phosphate, dopamine citrate, dopamine tartrate, or dopamine hydrobromide. Preferably, the concentration of dopamine source in the dopamine source solution is 0.3 mg / mL to 0.6 mg / mL; Preferably, the cerium source in the cerium source solution includes any one or a combination of at least two of cerium nitrate, cerium chloride, cerium sulfate, cerium acetate, cerium citrate, cerium tartrate, cerium nitrate hydrate, cerium chloride hydrate, cerium sulfate hydrate, cerium acetate hydrate, cerium citrate hydrate, or cerium tartrate hydrate. Preferably, the concentration of the cerium source in the cerium source solution is 35.0 mmol / L to 65.0 mmol / L.

9. The preparation method according to claim 7, characterized in that, The mixing also includes the incorporation of a buffer solution; Preferably, the buffer solution comprises a Bis-Tris solution and / or a Tris solution.

10. The application of the antioxidant nanomaterial according to any one of claims 1 to 6, characterized in that, The antioxidant nanomaterials are used to scavenge reactive oxygen species.

Images