Preparation method and application of red nano-selenium particles

Abstract

The invention provides a preparation method and application of red nano-selenium particles, and relates to the technical field of nano-medicines.The preparation method comprises the steps that sodium selenite is dissolved in ultrapure water, silicate microspheres containing copper, zinc and aluminum are added, the pH value is 4.8, 1.5 M of ascorbic acid solution is dropwise added while stirring, the temperature is increased till solid ascorbic acid is added, the pH value is adjusted through NaOH, and nano-selenium suspension liquid is obtained through stirring reaction; the preparation method comprises the following steps: mixing and stirring a nano-selenium suspension, a sodium alginate sulfydryl graphene oxide mixture and a chitosan oligosaccharide citric acid buffer solution, centrifugally washing, and freeze-drying to obtain red nano-selenium particles, and preparing the copper-zinc-containing aluminosilicate microspheres through mesoporous template calcination and copper-zinc co-doping. The red nano-selenium particles prepared by the method have a core-shell structure, uniform particle size, high oxidation resistance and remarkable interface bonding strength.

Description

Technical Field

[0001] This application relates to the field of nano-medicine technology, and particularly relates to a preparation method and application of red nano-selenium particles. Background Art

[0002] In the field of nanomedicine technology, the research and application of nanomaterials are booming at an unprecedented rate. As a nanomaterial with unique properties, nano-selenium, especially red nano-selenium particles, exhibit great application potential in the biomedical field due to their good biocompatibility, low toxicity, and remarkable antioxidant, anti-inflammatory, and anti-tumor biological activities. For example, they can be used as drug carriers for targeted drug delivery or directly for the treatment and prevention of diseases, and have broad application prospects in cancer treatment, cardiovascular disease prevention and treatment, etc. However, currently, there are still many difficult problems to be solved in the preparation and application of red nano-selenium particles. From the perspective of preparation, the primary problem is how to obtain red nano-selenium particles with uniform particle size, good dispersibility, and stability. Traditional preparation methods, such as chemical reduction methods and physical pulverization methods, are difficult to precisely control the particle size and morphology of nanoparticles. Chemical reduction methods usually require the use of a large amount of chemical reducing agents. These reducing agents may not only remain on the surface of nanoparticles, affecting their biological safety, but also introduce impurities during the reaction, interfering with the performance of nanoparticles. The nanoparticles prepared by physical pulverization methods have a wide particle size distribution range, which is difficult to meet the strict requirements for the uniformity of nanoparticles in the biomedical field. Moreover, during the preparation process, nanoparticles are extremely prone to agglomeration, resulting in poor dispersibility, which in turn affects their effect in subsequent applications. Even more troublesome is that the nano-selenium colloids prepared by existing methods will quickly aggregate even in a refrigerated environment, and obvious graying will occur within seven days. This stability defect directly hinders the process of pharmaceutical standardization, forcing researchers to turn to coating processes, while multi-layer coating weakens the biological activity of selenium itself, forming a vicious cycle. Looking at the current technical routes, the main defects do not exist in isolation but stem from deep-seated process logic defects. The out-of-control particle size in chemical reduction methods is a typical example: when the concentration of the reducing agent exceeds the critical point, the nucleation rate suddenly accelerates, causing the particle growth direction to deviate, and instantly generating ineffective products in the hundreds of nanometer range. This non-linear effect makes industrial scale-up full of uncertainties, and the performance of products in different batches varies greatly. The stabilizers introduced to inhibit agglomeration bring new problems: surfactants such as sodium dodecyl sulfate need to work in an acidic environment, resulting in residual hydrochloric acid ions in the system threatening biological safety; if natural stabilizers such as polysaccharides are used instead, although the toxicity is reduced, the coating layer will disintegrate due to the molecular chain breakage during dialysis, and the nano-selenium will be re-exposed and inactivated more quickly after re-exposure. The microbial method encounters physical barriers in separation and purification. The nano-selenium synthesized by bacteria is wrapped in the extracellular polymeric matrix, and to obtain pure particles, the biological membrane structure must be destroyed. The existing scheme of ultrasonic fragmentation combined with strong alkali treatment seriously damages the thiol active sites on the surface of selenium, and these sites are precisely the key functional domains for coupling with drug molecules. In terms of application, red nano-selenium particles also face many challenges.Due to its relatively special surface properties, it is difficult to combine with other biomaterials or drugs. How to achieve efficient loading and stable binding of red selenium nanoparticles with drugs is a key issue for their application in the field of drug delivery. In addition, the metabolic process and mechanism of action of red selenium nanoparticles in the body have not been fully clarified, which makes it difficult to evaluate their safety and effectiveness in clinical applications. At present, there are relatively few studies on the distribution, metabolic pathways, and long-term toxicity of red selenium nanoparticles in the body, lacking sufficient data to support their wide application in the biomedical field.

[0003] With the continuous development of nano-medicine technology, the demand for high-performance nano-materials is increasing day by day. Developing a new preparation method and application of red selenium nanoparticles is of crucial significance. The new preparation method can solve the problems existing in the prior art, such as uneven particle size, poor dispersibility, high preparation cost, and unstable color control, and obtain high-quality red selenium nanoparticles. At the application level, in-depth study of the mechanism of action and metabolic process of red selenium nanoparticles, and exploration of their combination methods with other biomaterials can give full play to their advantages in the biomedical field, promote the further development of nano-medicine technology, provide more effective means for the diagnosis and treatment of diseases, and meet the urgent clinical needs for new and efficient drugs and treatment methods.

[0004] In summary, in the field of preparation and application of red selenium nanoparticles, there are many deficiencies in the existing technology, which seriously restrict their development and application in the field of nano-medicine technology. Therefore, actively carrying out research on a new preparation method and application of red selenium nanoparticles to break through the existing technical bottlenecks has great significance and broad development prospects. Summary of the Invention

[0005] This application provides a preparation method and application of red selenium nanoparticles to solve the problems raised in the above background technology.

[0006] To solve the above technical problems, this application discloses a preparation method of red selenium nanoparticles, including the following steps: S1. Pre-reduction nucleation: Dissolve sodium selenite in ultrapure water, add copper-zinc-aluminum silicate microspheres, adjust the pH, stir at 300 rpm for 10 min at 30 °C, dropwise add 1.5 M ascorbic acid solution, and stir at 500 rpm for 30 min at 30 °C; S2. Main reduction growth: Raise the temperature, add solid ascorbic acid, adjust the pH, and stir to react to obtain a selenium nanoparticle suspension; S3. Stabilization treatment: Mix and stir the selenium nanoparticle suspension, a mixture of sodium alginate-thiolated graphene oxide, and chitosan-citric acid buffer solution at 40 °C for 60 min, centrifuge, wash, and freeze-dry to obtain red selenium nanoparticles.

[0007] Furthermore, the red nano-selenium particles prepared by the preparation method include sodium selenite, ascorbic acid, copper-zinc-aluminum silicate microspheres, a mixture of sodium alginate and mercapto-oxidized graphene, and a chitosan citrate buffer solution.

[0008] Furthermore, the red nano-selenium particles prepared by the preparation method include, by weight: 10-15 parts of sodium selenite, 26-32 parts of ascorbic acid, 3-6 parts of copper-zinc-aluminum silicate microspheres, 0.1-0.5 parts of a mixture of sodium alginate and mercapto-oxidized graphene, and 76-86 parts of a chitosan citrate buffer solution.

[0009] Furthermore, the preparation method of the copper-zinc-aluminum silicate microspheres in step S1 includes: a) Dissolve CTAB in ethanol, add TEOS and toluene to form substance A; b) Dissolve sodium meta-aluminate in deionized water containing ammonium hydroxide to form substance B; c) Add substance B to substance A, react at room temperature for 4 h, and calcine at 550 °C for 3 h; d) Disperse the calcined powder in water, add an aqueous P-123 solution, copper nitrate, zinc nitrate and ammonium hydroxide, calcine at 600 °C for 2 h, wash and dry to obtain copper-zinc-aluminum silicate microspheres.

[0010] Furthermore, in step S1, add copper-zinc-aluminum silicate microspheres, and adjust the pH to 4.8 with 0.1 M HCl; in step S2, raise the temperature to 45-55 °C, add solid ascorbic acid, and adjust the pH to 7.2 with 0.1 M NaOH.

[0011] Furthermore, the preparation method of the mixture of sodium alginate and mercapto-oxidized graphene includes adding sodium alginate to a mercapto-oxidized graphene solution, stirring at 80 °C for 8 h to obtain a mixture of sodium alginate and mercapto-oxidized graphene.

[0012] Furthermore, the mass ratio of sodium alginate to mercapto-oxidized graphene is 10:1.

[0013] Furthermore, the preparation method of the copper-zinc-aluminum silicate microspheres includes dissolving 1.5 parts of CTAB in 24 parts of EtOH by weight, adding 2.4 parts of TEOS and 0.6 parts of toluene to obtain substance A, dissolving 20 parts of sodium meta-aluminate in 26 parts of deionized water and 0.75 parts of ammonium hydroxide to obtain substance B, adding substance B to substance A, reacting at room temperature for 4 h, in order to remove CTA ions, calcine at 550 °C at a heating rate of 3 °C·min for 3 h, cool to room temperature to obtain a powder, disperse 30 parts of the powder in deionized water, add 20 parts of a 1.0 wt% aqueous P-123 solution, 1.0 part of 1.0 M copper nitrate, 1.0 part of 1.0 M zinc nitrate and 2.5 parts of ammonium hydroxide, calcine and cool, wash and dry to obtain copper-zinc-aluminum silicate microspheres.

[0014] Furthermore, heat it to 600 °C at a rate of 3 °C / min, calcine it at 600 °C for 2 h, cool it naturally to room temperature, wash it twice with deionized water, wash it once with EtOH, and dry it at 80 °C for 1 h to obtain copper-zinc-aluminum silicate microspheres.

[0015] Furthermore, the application of the red nano-selenium particles prepared by the preparation method in the preparation of a topical preparation, the topical preparation includes a wound repair gel.

[0016] The action mechanisms of the above raw material components are as follows: The copper-zinc-aluminum silicate microspheres, as the core functional material in the whole preparation process, provide a precise physical confinement space for the directional growth of nano-selenium with their unique porous structure. The mesoporous channels evenly distributed inside the microspheres can effectively adsorb and enrich selenite ions, and significantly inhibit the random agglomeration tendency during the nucleation stage through spatial confinement, laying a structural foundation for the subsequent formation of nanoparticles with uniform particle size. The copper-zinc bimetallic components in the microspheres play a synergistic catalytic function. Among them, zinc ions preferentially anchor the reaction precursors in an acidic environment through electrostatic attraction, and copper ions construct a redox cycle system with ascorbic acid to continuously accelerate the electron transfer process, ensuring the efficient conversion of selenite to elemental selenium. The aluminosilicate framework not only endows the microspheres with excellent thermal stability, but the abundant silanol groups on its surface can also form stable chemical bonds with the newly generated selenium atoms to prevent the migration and aggregation of nanoparticles.

[0017] Ascorbic acid, as a key reducing agent, plays a role by adopting a phased progressive strategy. In the pre-reduction stage, liquid ascorbic acid is used for mild reduction in a low-temperature environment, and the explosive nucleation phenomenon is avoided by precisely controlling the dropping rate. After entering the main reduction stage, solid ascorbic acid is converted to continuously supply hydrogen, inducing the orderly arrangement of selenium atoms along specific crystal planes in a near-neutral environment, and finally forming a thermodynamically stable red trigonal crystal structure. It should be noted that the coordination of the oxidation product of ascorbic acid, dehydroascorbic acid, with the surface of nano-selenium further optimizes the spherical morphology of the particles.

[0018] The sodium alginate-mercapto graphene oxide composite improves the system stability through multiple mechanisms. The graphene oxide sheets form a physical barrier network in the composite, effectively dividing the moving space of the nanoparticles. The thiol groups modified on its surface form strong covalent bonds with nano-selenium, forming a dense protective layer on the particle surface. The negative charges generated by the ionization of sodium alginate molecular chains in water form a strong electrostatic repulsion force, which, combined with the steric barrier formed by the hydration effect, jointly prevents the aggregation caused by van der Waals forces. The synergistic effect of this chemical bonding and steric hindrance fundamentally solves the aggregation problem of nano-selenium.

[0019] The chitosan oligosaccharide-citric acid buffer system focuses on constructing a functional core-shell structure. In an acidic buffer environment, protonated chitosan oligosaccharide and the negatively charged sodium alginate complex form a coating layer through electrostatic self-assembly, thereby constructing a barrier with strong interfacial properties around the nanoparticles. The biocompatibility of chitosan oligosaccharide itself and its chelating ability for heavy metal ions significantly reduce biological toxicity, while the citric acid buffer environment endows the coating layer with controlled release characteristics under slightly acidic conditions at the wound surface. This system ultimately realizes the dual-functional integration of active protection and targeted delivery.

[0020] The mechanism of action of the above preparation method is as follows: In the pre-reduction nucleation stage, precise nucleation is achieved by finely controlling the reaction environment. In the presence of copper-zinc-aluminum silicate microspheres, the acidic reaction system first promotes the selective adsorption of selenite by zinc ions to form a complex, significantly increasing the local concentration of reaction sites. The uniformly distributed nanopores inside the microspheres form a physical confinement space, strictly restricting the nucleation process to the preset position. The gradient dropping strategy of liquid ascorbic acid combined with mild stirring conditions enables the reduction reaction to proceed at a controllable rate, and the catalytic effect of copper ions maintains efficient electron transfer under low-temperature conditions. This multiple constraint mechanism ensures the generation of selenium atomic nuclei with extremely small size deviations.

[0021] In the main reduction growth stage, the crystal structure is optimized by regulating thermodynamic and kinetic parameters. The reaction system is heated to near the critical temperature of selenium phase change, triggering the directional transformation of amorphous selenium to crystalline selenium. The continuous addition of solid ascorbic acid provides an abundant atomic source, realizing the epitaxial growth of selenium atoms in a near-neutral environment. The special interfacial effect generated by the hydroxylation of the selenium crystal surface under alkaline conditions, combined with the molecular guiding effect of the oxidation product of ascorbic acid, jointly induces an isotropic growth mode. The fluid shear force formed by enhanced stirring effectively inhibits dendritic growth and promotes the mass transfer process, ultimately obtaining red trigonal crystalline selenium particles with high sphericity.

[0022] In the stabilization treatment stage, a multi-dimensional protection system is constructed. The nano-selenium suspension and the thiol-functionalized complex are mixed under temperature-controlled conditions, promoting the full covalent bonding of thiols to the selenium surface. The molecular chains of sodium alginate unfold in the complex to form a spatial barrier network, and the negatively charged layer generated by its ionization enhances the electrostatic stabilization effect. After adding the chitosan oligosaccharide-citric acid buffer solution, the layer-by-layer self-assembly process is completed under the drive of electrostatic attraction. The amino group of chitosan oligosaccharide forms a strong ionic crosslink with the carboxyl group of the complex, and at the same time, a three-dimensional network structure is constructed under the action of intermolecular hydrogen bonds. The freeze-drying process adopts a specific temperature curve, first forming a protective glassy matrix through deep freezing, and then fixing the core-shell structure through vacuum sublimation, completely retaining the active surface and pore structure of the nanoparticles.

[0023] The entire preparation process achieves technological breakthroughs through staged regulation. The confined catalysis in the pre-reduction stage controls the nucleation uniformity from the source, the crystal-oriented growth in the main reduction stage ensures the formation of stable crystal forms, and the multi-dimensional coating in the stabilization treatment constructs a long-term protection system. There is a deep synergistic effect among the components: the microspheres provide an ideal reaction interface for the reduction of ascorbic acid, the conversion products of ascorbic acid promote the binding of subsequent coating materials, and the functionalized complex and the chitosan system form a complementary and stable mechanism. This multi-level action mechanism ultimately breaks through the dual technical bottlenecks of uncontrolled particle size and poor stability in the preparation of traditional nano-selenium. The obtained product shows excellent antioxidant activity and biological functionality, providing an ideal carrier platform for the development of topical preparations.

[0024] Compared with the prior art, the present application provides a method for preparing red nano-selenium particles and its application, having the following beneficial effects: 1. In the present application, copper-zinc-aluminum silicate microspheres are used as mesoporous templates to guide nucleation, and a preparation method of pre-reduction nucleation + main reduction growth is designed. Combining with the stepwise reduction steps, the nucleation sites and growth rate of nano-selenium are effectively controlled, solving the problems of wide particle size distribution and uneven morphology in the traditional chemical reduction method, and preparing red nano-selenium particles with uniform particle size; 2. The present application adopts a double coating structure of sodium alginate-mercapto graphene oxide mixture and chitosan citrate buffer solution to stabilize the surface of nano-selenium through mercapto coordination and electrostatic interaction. Mercapto graphene oxide is used to coordinate with selenium, avoiding the masking of active sites in the traditional coating process. The antioxidant enzyme activity of the prepared red nano-selenium particles is not reduced due to coating, and at a concentration of 350 μg / mL, the scavenging effects on superoxide anion and glutathione are both significant; 3. In the present application, the reaction conditions are precisely controlled step by step to inhibit the non-linear nucleation effect. The microsphere template strengthens the structural stability through copper-zinc co-doping, and the copper-zinc synergistically enhances the effect, jointly playing a positive role in the antioxidant and interface binding properties of the prepared red nano-selenium particles; 4. Using natural materials chitosan oligosaccharide and sodium alginate to replace toxic surfactants and combining with a neutral buffer system not only reduces the ionic toxicity remaining in the acidic environment, but also makes the particles particularly suitable for applications in biomedical scenarios such as topical preparations, meeting the safety requirements in the biomedical field; 5. The red nano-selenium particles prepared in this application also have remarkable interfacial bonding strength. The mercapto-selenium covalent bond and the electrostatic self-assembly of chitosan / sodium alginate enhance the interfacial strength, and the double-metal doping in the microspheres optimizes the particle morphology uniformity, providing a more stable bonding interface for the coating layer. In summary, the method involved in this application overcomes the key bottlenecks in nano-selenium preparation such as particle size control, stability maintenance, activity retention, and biological safety through multi-dimensional innovations such as template-directed synthesis, active site protection, process parameter optimization, and biocompatible material adaptation, providing reliable technical support for the medical application of nano-selenium. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the FESEM image of the red nano-selenium particles in Example 1 of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining this application, and are not used to limit this application.

[0027] In addition, in this application, the descriptions such as "first" and "second" are only for descriptive purposes, and do not particularly refer to the order or sequence. Nor are they used to limit this application. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions and technical features between various embodiments can be combined with each other, but it must be based on the premise that those skilled in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by this application.

[0028] Unless otherwise specified, the examples and comparative examples are parallel experiments with the same components, component contents, preparation steps, and preparation parameters. The experimental methods in the following examples are all conventional methods unless otherwise specified; the test materials used in the following examples are all analytical reagents (A.R.) and are purchased from commercial channels unless otherwise specified.

[0029] Chitosan oligosaccharide was purchased from Shenzhen Nano Port Co., Ltd., with a degree of deacetylation ≥95% and a molecular weight of 2 kDa; sodium alginate was purchased from Sigma-Aldrich, W201502, with a concentration of 2% w / v and a viscosity of 250 mPa·s; nano-porous calcium silicate was purchased from Guangzhou Yifeng Chemical Technology Co., Ltd., model: calcium silicate TY-650, specification: 11,000 mesh (nano-scale); citrate buffer was purchased from Shanghai Maokang Biotechnology Co., Ltd., model: MS3529-500ML; mercapto-functionalized graphene oxide was purchased from Sigma-Aldrich, model number 778240-25MG; cetyltrimethylammonium bromide (CTAB, 96%, Aldrich); tetraethyl orthosilicate (TEOS, 99%, Aldrich); poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (P-123, MW: 5000, Aldrich); ammonium hydroxide solution (NH4OH, 25% NH3 in water, Merck) and absolute ethanol (EtOH, analytical reagent grade, VWR Chemicals).

[0030] Example 1: This example discloses a red nano-selenium particle, which comprises, by weight: 13 parts of sodium selenite, 30 parts of ascorbic acid, 4 parts of copper-zinc-aluminum silicate microspheres, 0.2 part of a sodium alginate-mercapto-functionalized graphene oxide mixture, and 82 parts of a chitosan oligosaccharide-citrate buffer; the 30 parts of ascorbic acid includes 20 parts of 1.5 M ascorbic acid solution and 10 parts of solid ascorbic acid.

[0031] The preparation method of the sodium alginate-mercapto-functionalized graphene oxide mixture includes adding sodium alginate to mercapto-functionalized graphene oxide, with a mass ratio of sodium alginate to mercapto-functionalized graphene oxide of 10:1, stirring at 80 °C for 8 h to obtain the sodium alginate-mercapto-functionalized graphene oxide mixture.

[0032] The preparation method of the chitosan oligosaccharide-citrate buffer includes adding chitosan oligosaccharide to the citrate buffer at room temperature, with a weight ratio of chitosan oligosaccharide to citrate buffer of 1:8, mixing under magnetic stirring at 400 rpm for 60 minutes, and filtering through a 0.22 μm filter membrane to obtain the chitosan oligosaccharide-citrate buffer.

[0033] Preparation of copper-zinc-aluminum silicate microspheres: Dissolve 1.5 parts of CTAB in 24 parts of EtOH by weight, add 2.4 parts of TEOS and 0.6 part of toluene to obtain substance A. Dissolve 20 parts of sodium aluminate in 26 parts of deionized water and 0.75 part of ammonium hydroxide to obtain substance B. Add substance B to substance A and react at room temperature for 4 h. To remove CTA ions, calcine at 550 °C at a heating rate of 3 °C·min⁻¹ for 3 h, cool to room temperature to obtain a powder. Disperse 30 parts of the powder in 1.0 part of deionized water, add 20 parts of 1.0 wt% P-123 aqueous solution, 1.0 part of 1.0 M copper nitrate, 1.0 part of 1.0 M zinc nitrate, and 2.5 parts of ammonium hydroxide, heat to 600 °C at a rate of 3 °C / min, calcine at 600 °C for 2 h, cool naturally to room temperature, wash twice with deionized water, wash once with EtOH, and dry at 80 °C for 1 h to obtain copper-zinc-aluminum silicate microspheres.

[0034] A preparation method of red nano selenium particles, applied to the described red nano selenium particles, comprising the following steps: S1. Pre-reduction nucleation: Dissolve sodium selenite in ultrapure water, add copper-zinc-aluminum silicate microspheres, adjust the pH to 4.8 with 0.1 M HCl, control the temperature at 30 °C, stir at 300 rpm for 10 min, and dropwise add 1.5 M ascorbic acid solution, stir at 500 rpm at 30 °C for 30 min.

[0035] S2. Main reduction growth: Heat the product obtained in step S1 to 50 °C, add solid ascorbic acid, adjust the pH to 7.2 with 0.1 M NaOH, stir at 600 rpm for 120 min, and stop the reaction when the solution turns dark red to obtain a nano selenium suspension. S3. Stabilization treatment: Stir the nano selenium suspension, the mixture of sodium alginate thiol graphene oxide, and the chitosan citrate buffer solution at 40 °C at 400 rpm for 60 min, centrifuge at 12000 rpm at 4 °C for 15 min, wash 3 times with ultrapure water, and freeze-dry to obtain red nano selenium particles.

[0036] Scan the red nano selenium particles prepared in Example 1 with a field emission scanning electron microscope. Figure 1 It is an FESEM image. It can be seen from the image that the particles have a uniform particle size distribution and a regular spherical structure. The particle size of the red selenium particles prepared by the preparation method using the template-directed effect of copper-zinc-aluminum silicate microspheres is controlled at the nano level, the particle surface is smooth, and there is no obvious agglomeration phenomenon.

[0037] Example 2: This example discloses a kind of red nano-selenium particles, which includes, by weight: 10 parts of sodium selenite, 26 parts of ascorbic acid, 3 parts of copper-zinc-aluminum silicate microspheres, 0.1 part of sodium alginate-mercapto graphene oxide mixture, and 76 parts of chitosan citrate buffer solution. Other contents are the same as those in Example 1.

[0038] Example 3: This example discloses a kind of red nano-selenium particles, which includes, by weight: 15 parts of sodium selenite, 32 parts of ascorbic acid, 6 parts of copper-zinc-aluminum silicate microspheres, 0.5 part of sodium alginate-mercapto graphene oxide mixture, and 86 parts of chitosan citrate buffer solution. Other contents are the same as those in Example 1.

[0039] Comparative Example 1 The difference from Example 1 is the lack of an equal weight portion of sodium alginate-mercapto graphene oxide mixture, and others are the same.

[0040] Comparative Example 2 The difference from Example 1 is the lack of an equal weight portion of copper nitrate when preparing aluminum silicate microspheres, and others are the same.

[0041] Comparative Example 3 The difference from Example 1 is the lack of an equal weight portion of zinc nitrate when preparing aluminum silicate microspheres, and others are the same.

[0042] Application Example 1 The application of the red nano-selenium particles prepared in Example 1 in preparing a wound repair gel is as follows: Dissolve sodium carboxymethylcellulose in ultrapure water at 50 °C, and swell for 24 hours to form a transparent colloid. Add glycerol, sodium hyaluronate and methylparaben, and mix them evenly; Ultrasonically disperse the red nano-selenium particles in chitosan citrate buffer solution, stir at 400 rpm for 30 min, adjust the pH to 5.5, and fill to obtain the wound repair gel.

[0043] Performance Test Perform antioxidant activity tests on the particles prepared in the examples and comparative examples. The results are shown in Table 1-4. Scavenging of ABTS free radicals: Use an ABTS free radical scavenging ability detection kit to detect the ABTS free radical scavenging activity of the red nano-selenium particles. Dilute the red nano-selenium particles prepared in Example 1 into solutions with concentrations of 25, 50, 100, 200, 350 μg / mL. After fully reacting with an equal amount of ABTS free radical solution, use an enzyme-labeled instrument to measure the absorbance of the solution at 405 nm. Set 3 replicates for each concentration. On this basis, calculate the ABTS free radical scavenging percentage of red nano-selenium particles at different concentrations. The results are shown in Table 1.

[0044] Scavenging of DPPH radicals: The DPPH radical scavenging activity of the red nano-selenium particles was detected using a DPPH radical scavenging ability test kit. The red nano-selenium particles prepared in Example 1 were diluted into 200, 400, and 350 μg / mL solutions. After fully reacting with an equal amount of DPPH radical solution, the absorbance of the solution at 515 nm was measured using an ELISA instrument, and 3 replicates were set for each concentration. On this basis, the DPPH radical scavenging percentages of the red nano-selenium particles of different concentrations were calculated, and the results are shown in Table 2.

[0045] Superoxide anion scavenging: Use superoxide dismutase (SOD) activity detection kit to detect SOD enzyme activity in red nano-selenium particles. O2- is generated through xanthine and xanthine oxidase reaction system, and O2- can reduce nitroblue tetrazolium to generate blue formazan, which absorbs at 560nm; SOD enzyme can scavenge O2-, thereby inhibiting the formation of formazan, and the ultraviolet absorption at 560nm decreases accordingly.

[0046] The red nano-selenium particles in Example 1 were diluted into solutions of different concentrations of 100, 200, 400, 800, and 1500 μg / mL, and another group was set as a blank control group, and 3 repetitions were set for each concentration. After the reaction was completed, the absorbance of the solution at 560 nm was measured using an ELISA instrument. On this basis, the O2- scavenging ability of the red nano-selenium particles of different concentrations was calculated to reflect the SOD enzyme activity of the particles, and the results are shown in Table 3.

[0047] Elimination of reduced glutathione (GPX enzyme activity): GPX enzyme activity in red nano-selenium particles was measured using a glutathione peroxidase (GSH-Px / GPX) activity detection kit. GPX enzyme can catalyze reduced glutathione (GSH) to generate oxidized glutathione (GSSG), reducing toxic hydrogen peroxide to non-toxic hydroxyl compounds (DTNB), which have a characteristic absorption peak at 412nm. The decrease in absorbance at 412nm can reflect the activity of GPX.

[0048] The red nano-selenium particles in Example 1 were diluted into solutions of different concentrations of 25, 100, 200, and 350 μg / mL, and another group was set as a blank control group, and 3 replicates were set for each concentration. After the reaction was completed, the absorbance of the solution at 412 nm was measured using an ELISA instrument. On this basis, the GSH scavenging ability of the red nano-selenium particles of different concentrations was calculated to reflect the GPX enzyme activity of the particles, and the results are shown in Table 4.

[0049] Table 1

[0050] Table 2

[0051] Table 3

[0052] Table 4

[0053] As can be seen from Table 1, the red nano-selenium particles prepared in Example 1 have significant ABTS radical scavenging ability. The scavenging rate increases significantly with the increase of concentration, showing a dose-dependence, indicating that the red nano-selenium particles prepared in Example 1 have strong antioxidant activity and can effectively neutralize ABTS radicals. As can be seen from Table 2, the scavenging of DPPH radicals by the red nano-selenium particles prepared in Example 1 also shows dose-dependence and high antioxidant activity. DPPH radicals are another commonly used antioxidant test model. A high scavenging rate indicates that the particles can effectively neutralize lipophilic radicals and are suitable for biomedical applications such as topical formulations. As can be seen from Table 3, the red nano-selenium particles prepared in Example 1 have superoxide dismutase (SOD)-like activity and can efficiently scavenge superoxide anions. The scavenging rate reaches 96.1% at 1500 μg / mL, showing a strong dose-dependence. The SOD enzyme activity indicates that the particles can mimic the function of natural antioxidant enzymes and may be used for anti-inflammatory or anti-aging applications in vivo. In addition, the copper-zinc synergy plays a positive role in enhancing antioxidant activity. As can be seen from Table 4, the red nano-selenium particles prepared in Example 1 have glutathione peroxidase (GPX)-like activity and can effectively scavenge reduced glutathione (GSH). The scavenging rate reaches 94.3% at 350 μg / mL, also showing dose-dependence. GPX enzyme activity is another key antioxidant mechanism, indicating that the particles can participate in the redox balance in cells. The scavenging rate exceeds 94% at high concentrations. Combining with the SOD activity data in Table 3, it proves that the particles have multi-enzyme synergistic antioxidant properties. As can be seen from Table 5, the red nano-selenium particles prepared in Example 1 have significant interfacial binding strength. The thiol-selenium covalent bond and the electrostatic self-assembly of chitosan / sodium alginate are the core to enhance the interfacial strength. In addition, the dual-metal doping in the microspheres optimizes the particle morphology uniformity and provides a more stable binding interface for the coating layer.

[0054] Interfacial binding strength test: Using nanoindentation method, the red nano-selenium particles prepared in Example 1 and Comparative Examples 1-3 were dispersed in ethanol, dropped on the surface of a silicon wafer to form a uniform monolayer film, and vacuum dried at 60 °C for 12 hours to ensure that the particles were firmly attached to the substrate. A Hysitron TI 950 nanoindentation instrument equipped with a Berkovich diamond indenter was used, and the parameters were set as follows: constant load mode: 0.5 mN, loading rate: 0.1 mN / s, holding time: 5 s; 20 independent particles were selected for indentation test for each sample, and the load-displacement curve was recorded. The shear strength (τ) was calculated through the Oliver-Pharr model, and the formula is as follows: , where is the maximum load, is the contact area, and the results are shown in Table 5.

[0055] Table 5

[0056] It can be seen from Table 5 that Example 1 has the highest shear strength, and the failure mainly occurs inside the particles, indicating that the sodium alginate-mercapto graphene oxide / chitosan coating layer is tightly combined with the nano-selenium core under the combined action of covalent bonds and static electricity. The confined synthesis of copper-zinc-aluminum silicate microspheres optimizes the structural integrity of the particles. The strength of Comparative Example 1 is significantly reduced, and the failure is the peeling of the particles from the substrate, indicating the lack of mercapto covalent bonding and the graphene physical barrier layer, resulting in insufficient interfacial bonding force. The lack of copper-zinc co-doping leads to uneven particle morphology and weakens the bonding force of the coating layer. In summary, it can be seen that the mercapto-selenium covalent bond from graphene oxide and the electrostatic self-assembly of chitosan / sodium alginate are the core to improve the interfacial strength. The dual-metal doping in the microspheres optimizes the uniformity of the particle morphology and provides a more stable bonding interface for the coating layer.

[0057] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. If these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application also intends to include these changes and variations.

Claims

1. A preparation method of red nano-selenium particles, characterized in that, It includes the following steps: S1. Pre-reduction nucleation: Dissolve sodium selenite in ultrapure water, add copper-zinc-aluminum silicate microspheres, adjust the pH, stir at 300 rpm for 10 min at 30 °C, dropwise add 1.5 M ascorbic acid solution, and stir at 500 rpm for 30 min at 30 °C; S2. Main reduction growth: Raise the temperature, add solid ascorbic acid, adjust the pH, and stir to react to obtain a nano-selenium suspension; S3. Stabilization treatment: Mix and stir the nano-selenium suspension, sodium alginate-mercapto-functionalized graphene oxide mixture, and chitosan-citric acid buffer solution at 40 °C for 60 min, centrifuge, wash, and freeze-dry to obtain red nano-selenium particles.

2. The preparation method according to claim 1, characterized in that, The red nano-selenium particles prepared by the described preparation method include sodium selenite, ascorbic acid, copper-zinc-aluminum silicate microspheres, sodium alginate-mercapto-functionalized graphene oxide mixture, and chitosan-citric acid buffer solution.

3. The preparation method according to claim 1, characterized in that, The red nano-selenium particles prepared by the described preparation method, by weight, include: 10 - 15 parts of sodium selenite, 26 - 32 parts of ascorbic acid, 3 - 6 parts of copper-zinc-aluminum silicate microspheres, 0.1 - 0.5 parts of sodium alginate-mercapto-functionalized graphene oxide mixture, and 76 - 86 parts of chitosan-citric acid buffer solution.

4. The preparation method according to claim 1, wherein The preparation method of the copper-zinc-aluminum silicate microspheres described in step S1 includes: a) Dissolve CTAB in ethanol, add TEOS and toluene to form substance A; b) Dissolve sodium meta-aluminate in deionized water containing ammonium hydroxide to form substance B; c) Add substance B to substance A, react at room temperature for 4 h, and calcine at 550 °C for 3 h; d) Disperse the calcined powder in water, add an aqueous solution of P-123, copper nitrate, zinc nitrate, and ammonium hydroxide, calcine at 600 °C for 2 h, wash and dry to obtain copper-zinc-aluminum silicate microspheres.

5. The preparation method according to claim 1, characterized in that, In step S1, add copper-zinc-aluminum silicate microspheres and adjust the pH to 4.8 with 0.1 M HCl; in step S2, raise the temperature to 45 - 55 °C, add solid ascorbic acid, and adjust the pH to 7.2 with 0.1 M NaOH.

6. The preparation method according to claim 1, characterized in that, The preparation method of the sodium alginate-mercapto-functionalized graphene oxide mixture includes adding sodium alginate to a mercapto-functionalized graphene oxide solution, and stirring at 80 °C for 8 h to obtain the sodium alginate-mercapto-functionalized graphene oxide mixture.

7. The preparation method according to claim 6, characterized in that, The mass ratio of sodium alginate to mercapto-functionalized graphene oxide is 10:

1.

8. The preparation method according to claim 4, characterized in that, The preparation method of the copper-zinc-aluminum silicate microspheres includes dissolving 1.5 parts of CTAB in 24 parts of EtOH by weight, adding 2.4 parts of TEOS and 0.6 parts of toluene to obtain substance A, dissolving 20 parts of sodium meta-aluminate in 26 parts of deionized water and 0.75 parts of ammonium hydroxide to obtain substance B, adding substance B to substance A, reacting at room temperature for 4 h, calcining at 550 °C at a heating rate of 3 °C·min for 3 h to remove CTA ions, cooling to room temperature to obtain a powder, dispersing 30 parts of the powder in deionized water, adding 20 parts of a 1.0 wt% aqueous solution of P-123, 1.0 part of 1.0 M copper nitrate, 1.0 part of 1.0 M zinc nitrate, and 2.5 parts of ammonium hydroxide, calcining and cooling, washing and drying to obtain copper-zinc-aluminum silicate microspheres.

9. The preparation method according to claim 8, characterized in that, Heat it to 600 °C at a rate of 3 °C / min, calcine it at 600 °C for 2 h, cool it naturally to room temperature, wash it twice with deionized water, wash it once with EtOH, and dry it at 80 °C for 1 h to obtain copper-zinc-aluminum silicate microspheres.

10. A red nano-selenium particle prepared by the preparation method according to any one of claims 1-9, characterized in that, Application of the red nano-selenium particles in the preparation of a topical preparation.

Images