Double-mesoporous asymmetric silicon dioxide nano pesticide carrier as well as preparation method and application thereof

Abstract

The invention discloses a double-mesoporous asymmetric silicon dioxide nano pesticide carrier as well as a preparation method and application thereof. The preparation method of the bimodal mesoporous asymmetric silicon dioxide nano pesticide carrier comprises the following steps: preparing an MSNs aqueous solution; hollow mesoporous silicon HMSS is prepared; preparing a nano pesticide carrier HMSSamp; and PMO. The double-mesoporous asymmetric silicon dioxide nano pesticide carrier prepared by the preparation method can realize the co-loading of two pesticides with different physicochemical properties without functional modification, has excellent plant leaf surface adhesion and insect body wall systemic penetration performance, and ensures the stability of the performance of different effective components in the nano mixed pesticide. The invention also provides a preparation method of the nano mixed pesticide. The insecticidal toxicity of the nano mixed pesticide prepared by the preparation method is obviously higher than that of the traditional physical mixed pesticide.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano pesticide preparations, and in particular relates to a double-mesoporous asymmetric silica nano pesticide carrier, a preparation method and application thereof. Background Art

[0002] Traditional chemical pesticides often suffer from low utilization rates and inconsistent effectiveness due to rainwater erosion and the instability of their active ingredients. Repeated applications are required to achieve effective control. As pesticide usage increases, pest resistance increases dramatically. To slow the development of resistance, two pesticides are often blended during pest control. This maximizes the strengths of each and enhances insecticide potency, making it a key strategy for sustainable agricultural development. Nanopesticides offer high utilization rates and significantly reduce their impact on the environment and non-target organisms. By combining nanotechnology with pesticide blending technology, chemical pesticides and biopesticides with different targets can be co-loaded onto nanocarriers to create dual-loaded nanopesticides. This approach combines the advantages of nanomaterials and pesticide blends, resulting in superior application effectiveness compared to traditional single-loaded nanopesticides.

[0003] Nano-blended pesticides can help synergize the advantages of two pesticides, enhancing toxicity and extending their duration. However, most nano-blended pesticides still have certain limitations: 1. Nanopesticides prepared using nanocarriers are mostly water-soluble, which hinders pesticide deposition on hydrophobic plant leaves and causes high rates of foliar pesticide shedding. 2. The outermost wax layer of insect body walls is lipophilic, making it difficult for most existing water-soluble nanopesticides to penetrate the insect body wall. 3. Most reported nano-blended pesticide carriers are monophilic materials, making it difficult to directly load two physicochemically distinct pesticides. Loading these two pesticides often requires extensive functional modifications to the nanomaterials. Therefore, dual-loaded nano-blended pesticides require further development.

[0004] Asymmetric nanoparticles are nanoparticles with different morphologies or properties on both sides of the same particle. Compared with single-component isotropic nanoparticles, asymmetric nanoparticles have unique application advantages: 1. They have adjustable surface properties and can be used as carriers to directly load active ingredients with different physical and chemical properties; 2. Due to the structural characteristics and special properties of their two components, asymmetric nanoparticles can achieve multimodal applications based on synergistic effects; 3. The asymmetric structure of the particles allows for regional isolation of the components, thereby reducing mutual interference between active ingredients with different properties and ensuring the stability of the performance of each region of the asymmetric nanoparticle to the greatest extent.

[0005] However, in the existing technology, there is little research on asymmetric nanopesticide carriers and nano-blended pesticides loaded with chemical pesticides and biological pesticides. Therefore, there is an urgent need in the existing technology for a double-mesoporous asymmetric silica nanopesticide carrier, its preparation method and application, which can achieve the co-loading of two pesticides with different physical and chemical properties without functional modification, has excellent plant leaf adhesion and insect body wall absorption and penetration performance, and ensures the stability of the performance of different active ingredients in the nano-blended pesticide. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a double-mesoporous asymmetric silica nanopesticide carrier, a preparation method and application thereof.

[0007] The purpose of the present invention is achieved through the following technical solutions: The present invention provides a method for preparing a double-mesoporous asymmetric silica nanopesticide carrier, comprising the following steps: 1) Pure water, ethanol, and ammonia water were added to a 500 ml round-bottom flask in a volume ratio of 50:347:8. After stirring at 25°C and 250 rpm for 10 min, tetraethyl orthosilicate (TES) was added and reacted for 1 h. The volume ratio of TES to ammonia water was 5:4. The mixture was centrifuged at 12,000 rpm for 20 min and washed three times to collect the precipitate to obtain a nano-mesoporous silica MSN precipitate. The nano-mesoporous silica MSN precipitate was then redispersed and dissolved in pure water to obtain an MSN aqueous solution. 2) Dissolve triethanolamine and hexadecyltrimethylammonium chloride in pure water at a mass ratio of 1:10, stir at 25°C for 1 hour, add MSNs aqueous solution, continue to add 0.64% by volume of tetraethyl orthosilicate dropwise, heat to 80°C and react for 1 hour; cool to 50°C, add anhydrous sodium carbonate at a solute ratio of 303000000:11, stir for 30 minutes, centrifuge at 12000 rpm for 20 minutes, wash three times, collect the precipitate, and dry to obtain hollow mesoporous silica HMSS; 3) Ethanol, pure water, cetyltrimethylammonium bromide, and aqueous ammonia were mixed to prepare a mixed solution, wherein the volume ratio of ethanol, pure water, and aqueous ammonia was 25:375:9, and the mass volume ratio of cetyltrimethylammonium bromide to the pure water in the mixed solution was 2:1 mg / mL. HMSS was added to the mixed solution at a mass ratio of HMSS to cetyltrimethylammonium bromide in the mixed solution of 1:1, and stirred at 30°C for 0.5 h. Bis-[3-(trimethoxysilyl)propyl]ethylenediamine was added at a volume ratio of bis-[3-(trimethoxysilyl)propyl]ethylenediamine to the pure water in the mixed solution of 1-2:1000. After reacting for 3 h, the mixture was centrifuged at 12,000 rpm for 20 min, washed three times, and the precipitate was collected. 4) Mixing hydrochloric acid and ethanol in a volume ratio of 1:60 to prepare a mixed solution, adding the precipitate obtained in step 3) to the mixed solution, stirring at 300 rpm for 4 hours, repeating three times, removing the template, and drying to obtain the nanopesticide carrier HMSS & PMO.

[0008] Preferably, in step 3), the volume ratio of bis-[3-(trimethoxysilyl)propyl]ethylenediamine to pure water in the mixed solution is 1:500.

[0009] The present invention also provides a double-mesoporous asymmetric silica nanopesticide carrier prepared by the above preparation method.

[0010] The present invention also provides a method for preparing a nano-mixed pesticide, comprising the following steps: 1) Weighing a dual-mesoporous asymmetric silica nanopesticide carrier and dissolving it in pure water, ultrasonically treating it for 10 minutes, adding a biopesticide, wherein the mass ratio of the dual-mesoporous asymmetric silica nanopesticide carrier to the biopesticide is 1-10:1, stirring at 4°C for 24 hours for loading, and then centrifuging, washing, and drying to obtain the nano-biopesticide; 2) Weighing the nano-biopesticide prepared in step 1), dissolving it in a solvent, and ultrasonically treating it for 10 minutes, then adding a chemical pesticide in a mass ratio of 1-10:1. Stirring at room temperature for 24 hours for loading, centrifuging, washing, and drying to obtain a nano-blended pesticide.

[0011] Preferably, the solvent is methanol, acetone or dimethylformamide.

[0012] The present invention also provides a nano-mixed pesticide prepared by the above preparation method.

[0013] The beneficial effects of the present invention are: 1) Most of the reported nanopesticide carriers are single-mesoporous structures, which make it difficult to directly load two pesticides with different physical and chemical properties. They need to undergo many functional modifications, which is time-consuming and labor-intensive. The present invention has a unique dual-mesoporous structure, which can achieve the co-loading of two pesticides with different physical and chemical properties without functional modification, simplifying the preparation steps and production costs of nano-blended pesticides. 2) Most of the reported nanopesticide carriers are single-hydrophilic materials, which make it difficult to adhere to hydrophobic plants and penetrate the body walls of insects. The present invention is composed of two types of nanoparticles, one hydrophilic and the other hydrophobic, and has excellent plant leaf adhesion and insect body wall absorption and penetration properties. By adjusting the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added, the composition ratio of HMSS and PMO in the present invention is adjusted, and nanopesticide carriers and nano-blended pesticides suitable for different application scenarios can be prepared. 3) This invention is composed of two components: hydrophilic HMSS and hydrophobic PMO. This dual-component structure allows for regional isolation to load pesticides with varying physical and chemical properties. Compared to common single-component nanopesticide carriers, this effectively reduces mutual interference between pesticides of varying properties, ensuring the stability of the performance of the different active ingredients in the nanopesticide blend to the greatest extent possible. 4) The nanopesticide blend prepared using HMSS & PMO combines the advantages of nanopesticide carriers, resulting in significantly higher insecticide potency than traditional physical blends, enhancing the practical application value of nanopesticides. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a flowchart of the preparation process of double-mesoporous asymmetric silica nanopesticide carriers; Figure 2 Transmission electron microscopy images of dual-mesoporous asymmetric silica nanopesticide carriers; the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-S was 75 μL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-M was 100 μL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-L was 150 μL. Figure 3 The scanning electron micrograph of the dual-mesoporous asymmetric silica nanopesticide carrier, wherein the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-S is 75 μL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-M is 100 μL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-L is 150 μL; Figure 4Figure 2 is the particle size distribution of the dual-mesoporous asymmetric silica nanopesticide carrier. The amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-S is 75 μL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-M is 100 μL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-L is 150 μL. Figure 5 The nitrogen adsorption-desorption isotherms of the dual-mesoporous asymmetric silica nanopesticide carriers are shown in Figure 2. The amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-S is 75 μL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-M is 100 μL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-L is 150 μL. Figure 6 The pore size distribution of the dual-mesoporous asymmetric silica nanopesticide carrier is shown in Figure 2. The amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-S is 75 μL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-M is 100 μL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-L is 150 μL. Figure 7 is the leaf retention amount of the dual-mesoporous asymmetric silica nanopesticide carrier; where A is corn leaf, B is gray cabbage leaf; H2O is water, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-S is 75 μL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-M is 100 μL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-L is 150 μL; Figure 8 is the contact angle of the dual-mesoporous asymmetric silica nanopesticide carrier on the leaf; A is the leaf corn, B is the leaf ash; H2O is water, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-S is 75 μL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-M is 100 μL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-L is 150 μL; Figure 9Images of the insect body wall penetration of dual-mesoporous asymmetric silica nanopesticide carriers; the three images on the left are fluorescence images, and the three images on the right are combined fluorescence and bright field images; the two images in row A used HMSS&PMO-S, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added was 75 μL; the two images in row B used HMSS&PMO-M, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added was 100 μL; the two images in row C used HMSS&PMO-L, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added was 150 μL; Figure 10 These are systemic imaging images of corn using dual-mesoporous asymmetric silica nanopesticide carriers; the three images on the left are fluorescence images, and the three images on the right are combined fluorescence and brightfield images; the two images in row A used HMSS&PMO-S, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added was 75 μL; the two images in row B used HMSS&PMO-M, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added was 100 μL; the two images in row C used HMSS&PMO-L, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added was 150 μL; Figure 11 is the zeta potential diagram of the dual-mesoporous asymmetric silica nanocomposite pesticide; among them, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-S is 75 μL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-M is 100 μL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-L is 150 μL; HMSS&PMO-MAT-EMA is a nanocomposite pesticide loaded with MAT and EMA; the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-MAT-EMA-S is 75 μL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-MAT-EMA-M is 100 μL. µL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-MAT-EMA-L was 150 µL; Figure 12Figure 3 is the insecticidal toxicity of double-mesoporous asymmetric silica nano-blended pesticides; among them, concrol is the control group, HMSS&PMO-MAT-EMA is the nano-blended pesticide loaded with MAT and EMA, and MAT-EMA is the mixed pesticide of MAT and EMA; Figure A is the toxic effect of HMSS&PMO-MAT-EMA and MAT-EMA on the grassland borer at a concentration of 2 mg / L; Figure B is the comparison of the toxic effect of HMSS&PMO-MAT-EMA and MAT-EMA on the grassland borer at concentrations of 0.3 mg / L and 0.6 mg / L after 72 hours; Figure C is the toxic effect of HMSS&PMO-MAT-EMA and MAT-EMA on the fall armyworm at a concentration of 2 mg / L; Figure D is the toxic effect of HMSS&PMO-MAT-EMA and MAT-EMA on the fall armyworm at concentrations of 0.3 mg / L and 0.6 mg / L after 72 hours. DETAILED DESCRIPTION

[0015] The present invention is described in detail below with reference to the accompanying drawings.

[0016] Example 1

[0017] 1. Preparation of double-mesoporous asymmetric silica nanopesticide carriers: See also Figure 1 , the present invention relates to a method for preparing a double-mesoporous asymmetric silica nanopesticide carrier, comprising the following steps; 1) Add 10 mL of pure water, 69.4 mL of ethanol, and 1.6 mL of ammonia water into a 500 mL round-bottom flask. Stir at 25°C and 250 rpm for 10 min. Then add 2 mL of tetraethyl orthosilicate and react for 1 h. Centrifuge at 12,000 rpm for 20 min and wash three times to collect the precipitate to obtain nano-mesoporous silica MSNs. The precipitate was redispersed and dissolved in 10 mL of pure water to prepare an MSNs aqueous solution.

[0018] 2) Dissolve 60 mg of triethanolamine and 6 g of hexadecyltrimethylammonium chloride in 60 mL of pure water. Stir at 25°C for 1 hour, then add 10 mL of MSNs aqueous solution. Continue dropwise adding 0.64% by volume tetraethyl orthosilicate (0.45 mL). Heat to 80°C and react for 1 hour. Cool to 50°C, add anhydrous sodium carbonate (2.12 nmol) at a solute ratio of 30:3000000:11, stir for 30 minutes, centrifuge at 12,000 rpm for 20 minutes, wash three times, collect the precipitate, and dry it to obtain hollow mesoporous silica (HMSS).

[0019] 3) Add 150 mg of HMSS to a mixed solution containing 5 mL of ethanol, 75 mL of pure water, 150 mg of hexadecyltrimethylammonium bromide, and 1.8 mL of aqueous ammonia. Stir at 30°C for 0.5 h. Then add 75 μL, 100 μL, and 150 μL of bis-[3-(trimethoxysilyl)propyl]ethylenediamine, respectively. After reacting for 3 h, centrifuge at 12,000 rpm for 20 min and wash three times to collect the precipitate.

[0020] 4) The resulting precipitate was added to a mixed solution containing 0.5 mL of hydrochloric acid and 30 mL of ethanol and stirred at 300 rpm for 4 h. This was repeated three times. The template was removed and the nanopesticide carrier HMSS & PMO was obtained after drying.

[0021] 2. Characterization test of HMSS&PMO: The structural characteristics, uniformity, and water dispersibility of the HMSS&PMO prepared according to the above preparation method were tested. When the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added was 75 μL, 100 μL, and 150 μL, the prepared HMSS&PMO were defined as HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L, respectively. The results are shown in Figure 2. Figure 2 、 3 As shown in the figure, transmission electron microscopy and scanning electron microscopy images show that the prepared nanoparticles are composed of spherical HMSS and rod-shaped PMO, with a uniform asymmetric structure, uniform particle size and good dispersion. The interior of HMSS is hollow, and the length of PMO gradually increases with the increase of the addition amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine. Figure 4 As shown in the figure, with the increase of the addition amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine, the particle size of HMSS&PMO gradually increases.

[0022] like Figure 5 、 6 As shown in the figure, it was found through nitrogen adsorption-desorption isotherms and pore size distribution that HMSS&PMO exhibited a typical type IV curve with an H3 hysteresis loop. HMSS&PMO-S, HMSS&PMO-M and HMSS&PMO-L all had a dual mesoporous structure. The pore sizes of HMSS&PMO-S, HMSS&PMO-M and HMSS&PMO-L were 2.0 nm / 3.0 nm, 2.1 nm / 3.6 nm and 2.2 nm / 4.0 nm, respectively.

[0023] 3. Performance testing of HMSS&PMO 1) Leaf surface retention and contact angle measurement Corn leaves and ash leaves were punched into small discs of equal area using a 1 cm diameter punch. A 1 mg / L HMSS & PMO-S aqueous solution, a 1 mg / L HMSS & PMO-M aqueous solution, and a 1 mg / L HMSS & PMO-L aqueous solution were used to treat the corn leaves (small discs) and ash leaves (small discs), respectively. The leaf surface retention and contact angles were investigated and compared with those of the pure water treatment group. The leaf surface retention results are shown in Figure 2. Figure 7 As shown, the retention rates of HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L on hydrophilic corn were significantly higher than those of the water-treated control, reaching 14–15 mg / cm². For hydrophobic cauliflower leaves, increasing the addition of bis-[3-(trimethoxysilyl)propyl]ethylenediamine gradually increased the length and specific gravity of the hydrophobic PMO in HMSS&PMO, leading to a gradual increase in its retention on the vegetable. HMSS&PMO-L had the highest retention rate (nearly 10 mg / cm²), significantly superior to the water-treated control.

[0024] The contact angle results are as follows Figure 8 As shown, the contact angles of HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L on corn and ash leaves were all smaller than those of the water-treated control group. HMSS&PMO, as a pesticide carrier, facilitates adhesion and spreading on plant leaves. As the addition amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine increases, the contact angles of HMSS&PMO on corn and ash leaves gradually decrease. These experiments show that by adjusting the addition amounts of HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L, different HMSS&PMOs can be prepared, which are suitable for plant leaves with different physical and chemical properties.

[0025] 2) Analysis of insect body wall penetration and plant systemic absorption Healthy, uniform-sized fourth-instar larvae of Spodoptera frugiperda were selected and loaded with the fluorescent dye FITC using HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L. The larval body walls were treated using the drip method. After treatment, the larvae were placed in an incubator at 25±1°C and 40% relative humidity for 3 hours. A frozen section technique was used to prepare longitudinal sections of the larvae with a thickness of 10 μm, which were then observed under a fluorescence confocal microscope (excitation wavelength 488 nm, emission wavelength 520 nm). The results are shown in Figure 2. Figure 9As shown in the figure, fluorescently labeled HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L all have significant green fluorescence in the insect body, indicating that HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L can overcome the natural barrier of the insect cuticle and efficiently penetrate the body wall of the fall armyworm. Using HMSS&PMO as a carrier to load pesticides can help improve the delivery efficiency and systemicity of pesticides.

[0026] Healthy, uniformly grown corn seedlings (three-leaf stage) were selected and randomly divided into two groups. HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L were loaded with the fluorescent dye FITC and evenly applied to the surface of the top leaves. After treatment, the corn plants were incubated at 25±1°C with a 16h / 8h photoperiod for 6 hours. Fluorescence imaging of the corn plants was performed using a biomacromolecule imaging system. The results are shown in Figure 2. Figure 10 As shown, after the corn leaves were treated with fluorescently labeled HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L, significant green fluorescence was observed in different parts of the corn plants, indicating that HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L all exhibited significant systemic and top-down transport and delivery capabilities. Using HMSS&PMO as a carrier to load pesticides can help improve the absorption and distribution of pesticides on crop leaves.

[0027] Example 2

[0028] 1. Preparation of nano-blended pesticides with HMSS & PMO as carriers 1) Biopesticide loading Taking HMSS&PMO loaded model pesticide matrine (MAT) as an example, nanomatrine (HMSS&PMO-MAT) was prepared.

[0029] The nanopesticide carriers HMSS & PMO-S, HMSS & PMO-M, and HMSS & PMO-L prepared in Example 1 were loaded with the biopesticide matrine at a mass ratio of 1-10:1. 30 mg of HMSS & PMO was weighed and dissolved in 60 ml of pure water. After ultrasonic treatment for 10 minutes, 30-3 mg of the biopesticide was added. The carriers were stirred at 4°C for 24 hours for loading. The carriers were then centrifuged, washed, and dried to obtain the nanopesticide HMSS & PMO-MAT. The biopesticide was a microbial pesticide, dsRNA, peptide, or protein.

[0030] 2) Preparation of nano-blended pesticides Taking HMSS&PMO-MAT further loaded with the model pesticide emamectin benzoate (EMA) as an example, a nano-blended pesticide (HMSS&PMO-MAT-EMA) was prepared.

[0031] The nanopesticide prepared in the above steps was loaded with the model pesticide emamectin benzoate at a mass ratio of 1-10:1. 30 mg of the nanopesticide prepared in step 1) was dissolved in 60 mL of methanol (or acetone or dimethylformamide, depending on the solubility characteristics of the pesticide). After ultrasonic treatment for 10 minutes, 30-3 mg of the chemical pesticide was added and stirred at room temperature for 24 hours for loading. The mixture was then centrifuged, washed, and dried to obtain the nanocomposite pesticides HMSS & PMO-MAT-EMA-S, HMSS & PMO-MAT-EMA-M, and HMSS & PMO-MAT-EMA-L.

[0032] 2. Characterization and testing of nano-blended pesticides MSS & PMO-MAT-EMA 1) Zeta potential test The Zeta potential of HMSS&PMO-S, HMSS&PMO-M, HMSS&PMO-L nanocarriers and their corresponding nano-blended pesticides HMSS&PMO-MAT-EMA-S, HMSS&PMO-MAT-EMA-M, HMSS&PMO-MAT-EMA-L were tested. Figure 11 As shown, the zeta potentials of HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L were 10.08 mV, 7.73 mV, and 0.28 mV, respectively, indicating a positive charge. After loading with MAT and EMA to form HMSS&PMO-MAT-EMA-S, HMSS&PMO-MAT-EMA-M, and HMSS&PMO-MAT-EMA-L, the potentials decreased to −13.54 mV, −2.96 mV, and −12.2 mV, respectively. Loading of the two pesticides resulted in a shift in zeta potential from positive to negative, indicating successful loading of MAT and EMA.

[0033] 2) Drug loading analysis The drug loading capacity of the nanocomposite pesticides HMSS & PMO-MAT-EMA-S, HMSS & PMO-MAT-EMA-M, and HMSS & PMO-MAT-EMA-L prepared in Example 2 for two pesticides (MAT and EMA) was tested. The loading rate and drug loading were determined by high-performance liquid chromatography. MAT was determined using a 1260 HPLC with a mobile phase consisting of acetonitrile + ethanol + 3% phosphoric acid solution (84 + 6 + 6, volume ratio) at a flow rate of 1.0 mL / min, a column temperature of 30°C (+0.5°C), a UV detection wavelength of 220 nm, an injection volume of 10 μL, and an XDB C18 column. EMA was determined using a mobile phase consisting of methanol + water (92 + 8, volume ratio) at a flow rate of 1.0 mL / min, a column temperature of 30°C (+0.5°C), a UV detection wavelength of 240 nm, and an injection volume of 10 μL. The column was an XDB C18 column. The results are shown in Table 1. HMSS&PMO-MAT-EMA-S achieved drug loadings of 49.25% and 4.82% for MAT and EMA, respectively; HMSS&PMO-MAT-EMA-M achieved drug loadings of 43.79% and 10.87% for MAT and EMA, respectively; and HMSS&PMO-MAT-EMA-L achieved drug loadings of 18.59% and 35.48% for MAT and EMA, respectively. The HMSS&PMO pesticide nanocarriers achieved co-loading of two pesticides with different physicochemical properties, with total pesticide loadings reaching 54.07%, 54.66%, and 54.07%, respectively.

[0034] Table 1 Drug loading of MAT and EMA in HMSS&PMO-MAT-EMA sample Drug loading of MAT / % Drug loading of EMA / % HMSS&PMO-MAT-EMA-S 49.25 4.82 HMSS&PMO-MAT-EMA-M 43.79 10.87 HMSS&PMO-MAT-EMA-L 18.59 35.48 3. Insecticidal toxicity test Based on its optimal retention and minimal contact angle on corn and leeks, HMSS&PMO-L was selected as a carrier for MAT and EMA. The resulting nanopesticide, MSS&PMO-MAT-EMA, was tested using a leaf dip method for its insecticidal toxicity against third-instar larvae of two lepidopteran pests: Spodoptera frugiperda and Sedge borer. Leaves were immersed in aqueous HMSS&PMO-MAT-EMA solutions at concentrations of 0.1 mg / L, 0.3 mg / L, 0.6 mg / L, 0.8 mg / L, and 1.0 mg / L for 30 seconds. The leaves were then removed, air-dried, and fed to insects. Mortality was observed 72 hours after treatment, and the results were analyzed using PoloPlus software. The indoor toxicity results are shown in Tables 2 and 3. The LC values ​​of the nanopesticides (HMSS&PMO-MAT-EMA, HMSS&PMO-MAT, and HMSS&PMO-EMA) prepared with HMSS&PMO nanopesticide carriers against two lepidopteran pests are shown in Tables 2 and 3.50 The values ​​were significantly higher than those of the original pesticides (MAT-EMA, MAT, EMA), proving that HMSS&PMO as a nanopesticide carrier has the advantage of enhancing the insecticidal toxicity of pesticides. In addition, the LC values ​​of HMSS&PMO-MAT-EMA against the larvae of Spodoptera frugiperda were 50 The value (0.224 mg / L) was lower than that of MAT-EMA physical mixed pesticide (LC 50 =0.381 mg / L), nano single loaded pesticide HMSS&PMO-MAT (LC 50 =3.028 mg / L) and HMSS&PMO-EMA (LC 50 =0.275 mg / L). HMSS & PMO-MAT-EMA against the larvae of Spodoptera frugiperda (LC) 50 The value (0.338 mg / L) was also lower than that of MAT-EMA physical mixed pesticide (LC 50 =0.612 mg / L), nano single loaded pesticide HMSS&PMO-MAT (LC 50 =3.514 mg / L) and HMSS&PMO-EMA (LC 50 =0.373 mg / L). This indicates that HMSS&PMO-MAT-EMA nano-blended pesticide has higher insecticidal toxicity than traditional physical mixed pesticides and nano-single loaded pesticides.

[0035] Table 2. Toxicity of HMSS & PMO-MAT-EMA to Spodoptera frugiperda Treatment <![CDATA[LC 50 mg / L]]> 95%Cl Slope±SE EMA 0.387 0.357-0.423 2.169±0.231 MAT 7.691 7.007-8.894 1.835±0.238 MAT-EMA 0.381 0.348-0.442 1.894±0.211 HMSS&PMO-EMA 0.275 0.256-0.298 2.249±0.217 HMSS&PMO-MAT 3.028 2.798-3.314 2.156±0.199 HMSS&PMO-MAT-EMA 0.224 0.206-0.248 1.969±0.205 Table 3. Toxicity of HMSS & PMO-MAT-EMA to Spodoptera frugiperda Treatment <![CDATA[LC 50 mg / L]]> 95%Cl Slope±SE EMA 0.594 0.543 – 0.658 1.894±0.236 MAT 11.217 10.106 – 12.588 1.678±0.252 MAT-EMA 0.612 0.563 – 0.676 1.964±0.214 HMSS&PMO-EMA 0.373 0.351 – 0.402 2.385±1.776 HMSS&PMO-MAT 3.514 3.262 – 3.836 2.203±0.225 HMSS&PMO-MAT-EMA 0.338 0.312 – 0.371 2.115±0.198 The 3rd instar larvae of Spodoptera frugiperda and Spodoptera frugiperda were used as model insects. HMSS&PMO-MAT-EMA and MAT-EMA mixed pesticides at concentrations of 0.3 mg / L, 0.6 mg / L and 2 mg / L were used to treat Spodoptera frugiperda and Spodoptera frugiperda, and the mortality of the test insects within 96 hours was compared. Figure 12As shown, Figure A is the toxic effect of HMSS&PMO-MAT-EMA and MAT-EMA on meadow borer at a concentration of 2 mg / L. Compared with the control group, the mortality rates at 12h, 24h, 36h, 48h, 60h, 72h, 84h and 96h were investigated respectively; Figure B is the comparison of the toxic effect of HMSS&PMO-MAT-EMA and MAT-EMA on meadow borer at 0.3 mg / L and 0.6 mg / L concentrations at 72h; Figure C is 2 The toxic effects of HMSS&PMO-MAT-EMA and MAT-EMA on Spodoptera frugiperda at concentrations of 0.6 mg / L and 1.5 mg / L were investigated, with mortality rates measured at 12, 24, 36, 48, 60, 72, 84, and 96 hours. Figure D shows the toxic effects of HMSS&PMO-MAT-EMA and MAT-EMA on Spodoptera frugiperda at concentrations of 0.3 mg / L and 0.6 mg / L at 72 hours. The results showed that the mortality rate of the nanopesticide HMSS&PMO-MAT-EMA against both lepidopteran pests within 96 hours was significantly higher than that of the MAT-EMA blended pesticide at the same concentration, demonstrating that HMSS&PMO, as a nanopesticide carrier, can improve the rapidity and enhance the activity of pesticides.

[0036] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a double-mesoporous asymmetric silica nanopesticide carrier, characterized in that The steps include: 1) Pure water, ethanol, and ammonia water were added to a 500 ml round-bottom flask in a volume ratio of 50:347:

8. After stirring at 25°C and 250 rpm for 10 min, tetraethyl orthosilicate was added and reacted for 1 h. The volume ratio of tetraethyl orthosilicate to ammonia water was 5:

4. The mixture was centrifuged at 12,000 rpm for 20 min and washed three times to collect the precipitate to obtain a nano-mesoporous silica MSN precipitate. The nano-mesoporous silica MSN precipitate was redispersed and dissolved in pure water to obtain an MSN aqueous solution. 2) Dissolve triethanolamine and hexadecyltrimethylammonium chloride in pure water at a mass ratio of 1:10, stir at 25°C for 1 hour, add MSNs aqueous solution, continue to add 0.64% by volume of tetraethyl orthosilicate dropwise, heat to 80°C and react for 1 hour; cool to 50°C, add anhydrous sodium carbonate at a solute ratio of 303000000:11, stir for 30 minutes, centrifuge at 12000 rpm for 20 minutes, wash three times, collect the precipitate, and dry to obtain hollow mesoporous silica HMSS; 3) Ethanol, pure water, cetyltrimethylammonium bromide, and aqueous ammonia were mixed to prepare a mixed solution, wherein the volume ratio of ethanol, pure water, and aqueous ammonia was 25:375:9, and the mass volume ratio of cetyltrimethylammonium bromide to the pure water in the mixed solution was 2:1 mg / mL. HMSS was added to the mixed solution at a mass ratio of HMSS to cetyltrimethylammonium bromide in the mixed solution of 1:1, and stirred at 30°C for 0.5 h. Bis-[3-(trimethoxysilyl)propyl]ethylenediamine was added at a volume ratio of bis-[3-(trimethoxysilyl)propyl]ethylenediamine to the pure water in the mixed solution of 1-2:1000. After reacting for 3 h, the mixture was centrifuged at 12,000 rpm for 20 min, washed three times, and the precipitate was collected. 4) Mixing hydrochloric acid and ethanol in a volume ratio of 1:60 to prepare a mixed solution, adding the precipitate obtained in step 3) to the mixed solution, stirring at 300 rpm for 4 hours, repeating three times, removing the template, and drying to obtain the nanopesticide carrier HMSS & PMO.

2. The method for preparing a dual-mesoporous asymmetric silica nanopesticide carrier according to claim 1, characterized in that: In step 3), the volume ratio of bis-[3-(trimethoxysilyl)propyl]ethylenediamine to pure water in the mixed solution is 1:

500.

3. A double-mesoporous asymmetric silica nanopesticide carrier prepared by the preparation method according to claim 1.

4. A method for preparing a nano-mixed pesticide, characterized in that The steps include: 1) Weigh the dual-mesoporous asymmetric silica nanopesticide carrier according to claim 3 and dissolve it in pure water. After ultrasonic treatment for 10 minutes, add the biopesticide, with the mass ratio of the dual-mesoporous asymmetric silica nanopesticide carrier to the biopesticide being 1-10:

1. Stir at 4°C for 24 hours for loading, then centrifuge, wash, and dry to obtain the nano-biopesticide. 2) Weighing the nano-biopesticide prepared in step 1), dissolving it in a solvent, and ultrasonically treating it for 10 minutes, then adding a chemical pesticide in a mass ratio of 1-10:

1. Stirring at room temperature for 24 hours for loading, centrifuging, washing, and drying to obtain a nano-blended pesticide.

5. The method for preparing a nano-blended pesticide according to claim 4, wherein: The solvent is methanol, acetone or dimethylformamide.

6. The nano-compound pesticide prepared by the preparation method according to claim 4.

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