A dual-mesoporous asymmetric silica nanopesticide carrier, its preparation method and application

Abstract

This invention discloses a dual-mesoporous asymmetric silica nanopesticide carrier, its preparation method, and its applications. The preparation method of the dual-mesoporous asymmetric silica nanopesticide carrier includes the following steps: preparing an aqueous solution of MSNs; preparing hollow mesoporous silica (HMSS); and preparing the nanopesticide carrier HMSS&PMO. The dual-mesoporous asymmetric silica nanopesticide carrier prepared by this method can achieve the co-loading of two pesticides with different physicochemical properties without functionalization modification. It exhibits excellent adhesion to plant leaves and internal penetration into insect body walls, ensuring the stability of the performance of different active ingredients in the nanopesticide mixture. This invention also provides a method for preparing nanopesticide mixtures, which yield nanopesticide mixtures with significantly higher insecticidal toxicity than traditional physically mixed pesticides.

Description

Technical Field

[0001] This invention belongs to the field of nanopesticide formulation technology, specifically relating to a dual-mesoporous asymmetric silica nanopesticide carrier, its preparation method, and its application. Background Technology

[0002] Traditional chemical pesticides often suffer from low utilization rates and unstable efficacy due to rain erosion and the instability of active ingredients, requiring repeated applications to achieve control. Furthermore, with increasing pesticide use, pest resistance is rapidly developing. To delay the development of resistance, it is common practice to mix two pesticides during pest control. This leverages the strengths of each pesticide and enhances their toxicity, representing a crucial strategy for sustainable agricultural development. Nanopesticides offer high utilization rates and significantly reduce environmental and non-target organism impacts. Combining nanotechnology with pesticide mixing technology allows for the co-loading of chemical and biological pesticides with different targets onto nanocarriers, creating dual-loaded nanopesticide mixtures. This approach combines the advantages of nanomaterials and pesticide combinations, resulting in better application effects than traditional single-loaded nanopesticides.

[0003] Nanoparticle-based pesticide blends can help synergize the beneficial effects of two pesticides, enhancing toxicity and prolonging efficacy. However, most nanoparticle-based pesticide blends still have certain limitations: 1. Nanoparticle pesticides prepared based on nanocarriers are mostly water-soluble, leading to pesticide deposition difficulties and high pesticide shedding rates on the leaves of hydrophobic plants; 2. The outermost wax layer of insect body walls is lipophilic, making it difficult for most existing water-soluble nanoparticle pesticides to penetrate them; 3. Most reported nanoparticle-based pesticide blend carriers are monophilic materials, making it difficult to directly load two pesticides with different physicochemical properties. When loading two pesticides with different physicochemical properties, the nanomaterials often require extensive functional modifications. Therefore, dual-loaded nanoparticle-based pesticide blends still require further development.

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

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

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a dual mesoporous asymmetric silica nanopesticide carrier, its preparation method and application.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] This invention provides a method for preparing a dual-mesoporous asymmetric silica nanopesticide carrier, comprising the following steps:

[0009] 1) Add pure water, ethanol and ammonia water in a volume ratio of 50:347:8 to a 500ml round bottom flask. Stir at 25℃ and 250rpm for 10min, then add tetraethyl orthosilicate and react for 1h. The volume ratio of tetraethyl orthosilicate to ammonia water is 5:4. Centrifuge at 12000rpm for 20min, wash 3 times and collect the precipitate to obtain nanoporous silica MSNs precipitate. Redisperse and dissolve the nanoporous silica MSNs precipitate in pure water to obtain an MSNs aqueous solution.

[0010] 2) Dissolve triethanolamine and hexadecyltrimethylammonium chloride in pure water at a mass ratio of 1:10. Stir at 25°C for 1 hour, then add MSNs aqueous solution, and continue to add tetraethyl orthosilicate (0.64% by volume). Heat to 80°C and react for 1 hour. Cool to 50°C, then add anhydrous sodium carbonate at a solute ratio of 303000000:11 and stir for 30 minutes. Centrifuge at 12000 rpm for 20 minutes, wash 3 times, collect the precipitate, and dry to obtain hollow mesoporous silica HMSS.

[0011] 3) A mixed solution was prepared by mixing ethanol, pure water, hexadecyltrimethylammonium bromide and ammonia, wherein the volume ratio of ethanol, pure water and ammonia was 25:375:9, and the mass-volume ratio of hexadecyltrimethylammonium bromide to pure water in the mixed solution was 2:1 mg / mL. HMSS was added to the mixed solution, and the mass ratio of HMSS to hexadecyltrimethylammonium bromide in the mixed solution was 1:1. The mixture was stirred at 30℃ for 0.5 h, and then bis-[3-(trimethoxysilyl)propyl]ethylenediamine was added, wherein the volume ratio of bis-[3-(trimethoxysilyl)propyl]ethylenediamine to pure water in the mixed solution was 1-2:1000. After reacting for 3 h, the mixture was centrifuged at 12000 rpm for 20 min, washed 3 times, and the precipitate was collected.

[0012] 4) Prepare a mixed solution by mixing hydrochloric acid and ethanol at a volume ratio of 1:60. Add the precipitate obtained in step 3) to the mixed solution and stir at 300 rpm for 4 hours. Repeat 3 times, remove the template, and dry to obtain the nano-pesticide carrier HMSS&PMO.

[0013] Preferably, in step 3), the volume ratio of bis-[3-(trimethoxysilyl)propyl]ethylenediamine to pure water in the mixed solution is 1:500.

[0014] The present invention also provides a dual-mesoporous asymmetric silica nanopesticide carrier prepared by the above preparation method.

[0015] This invention also provides a method for preparing nano-compound pesticides, comprising the following steps:

[0016] 1) Weigh out the dual mesoporous asymmetric silica nanopesticide carrier and dissolve it in pure water. After ultrasonic treatment for 10 min, add the biological pesticide. The mass ratio of the dual mesoporous asymmetric silica nanopesticide carrier to the biological pesticide is 1-10:1. Stir at 4℃ for 24 h to load the pesticide. Then centrifuge, wash and dry to obtain nano-biological pesticide.

[0017] 2) Weigh the nano-biological pesticide obtained in step 1), dissolve it in a solvent, treat it with ultrasound for 10 minutes, add chemical pesticide, the mass ratio of the nano-biological pesticide to the chemical pesticide is 1-10:1, stir at room temperature for 24 hours to load, and then centrifuge, wash and dry to obtain nano-mixed pesticide.

[0018] Preferably, the solvent is methanol, acetone, or dimethylformamide.

[0019] The present invention also provides nano-mixed pesticides prepared by the above preparation method.

[0020] The beneficial effects of this invention are: 1) Most reported nanopesticide carriers are single-mesoporous structures, making it difficult to directly load two pesticides with different physicochemical properties, requiring numerous functional modifications, which is time-consuming and labor-intensive. This invention, however, has a unique double-mesoporous structure, enabling the co-loading of two pesticides with different physicochemical properties without functional modifications, simplifying the preparation steps and reducing production costs of nano-mixed pesticides. 2) Most reported nanopesticide carriers are single-hydrophilic materials, making it difficult to achieve adhesion to hydrophobic plants and penetration into insect body walls. This invention, composed of two types of nanoparticles, one hydrophilic and one hydrophobic, exhibits excellent adhesion to plant leaves and internal penetration into insect body walls. Furthermore, by adjusting the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added, the composition ratio of HMSS and PMO in this invention can be adjusted, allowing the preparation of nanopesticide carriers and nano-mixed pesticides suitable for different application scenarios. 3) This invention consists of two components: hydrophilic HMSS and hydrophobic PMO. This two-component structure allows for regional isolation to load pesticides with different physicochemical properties. Compared to common single-component nanopesticide carriers, it effectively reduces the mutual interference between pesticides with different properties, maximizing the stability of the performance of different active ingredients in the nano-mixed pesticide. 4) The nano-mixed pesticide prepared based on HMSS & PMO in this invention combines the advantages of nanopesticide carriers, exhibiting significantly higher insecticidal toxicity than traditional physically mixed pesticides, thus enhancing the practical application value of nanopesticides. Attached Figure Description

[0021] Figure 1 A flowchart illustrating the preparation process of dual-mesoporous asymmetric silica nanopesticide carriers;

[0022] Figure 2 Transmission electron microscopy (TEM) images of dual-mesoporous asymmetric silica nanopesticide carriers; wherein, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-S is 75 µL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-M is 100 µL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-L is 150 µL;

[0023] Figure 3 The images show scanning electron microscope (SEM) images of the dual-mesoporous asymmetric silica nanopesticide carriers. In HMSS&PMO-S, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added is 75 µL; in HMSS&PMO-M, the amount is 100 µL; and in HMSS&PMO-L, the amount is 150 µL.

[0024] Figure 4The particle size distribution diagram shows the particle size distribution of the dual-mesoporous asymmetric silica nanopesticide carriers. Among them, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-S is 75 µL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-M is 100 µL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-L is 150 µL.

[0025] Figure 5 The nitrogen adsorption-desorption isotherm of the dual-mesoporous asymmetric silica nanopesticide carrier is shown; among them, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-S is 75 µL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-M is 100 µL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-L is 150 µL;

[0026] Figure 6 The pore size distribution of the dual-mesoporous asymmetric silica nanopesticide carriers is shown; specifically, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-S is 75 µL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-M is 100 µL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-L is 150 µL.

[0027] Figure 7 The leaf retention of the dual-mesoporous asymmetric silica nanopesticide carrier is represented by A, where A is corn leaf and B is lamb's quarters leaf; H2O is water; the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-S is 75 µL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-M is 100 µL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-L is 150 µL.

[0028] Figure 8 The contact angle of the dual-mesoporous asymmetric silica nanopesticide carrier on a leaf is shown; where A is a corn leaf and B is a lambsquarters leaf; H2O is water; the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-S is 75 µL, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-M is 100 µL, and the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added in HMSS&PMO-L is 150 µL.

[0029] Figure 9Images showing the insect body wall penetration of the dual-mesoporous asymmetric silica nanopesticide carrier; the three images on the left are fluorescence images, and the three images on the right are fluorescence and light juxtaposition images; the two images in row A use HMSS&PMO-S with 75 µL of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added; the two images in row B use HMSS&PMO-M with 100 µL of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added; the two images in row C use HMSS&PMO-L with 150 µL of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added.

[0030] Figure 10 Image showing the systemic activity of maize nanoparticles carrying dual-mesoporous asymmetric silica nanoparticles; the three images on the left are fluorescence images, and the three images on the right are fluorescence and light juxtaposition images; the two images in row A were created using HMSS&PMO-S with 75 µL of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added; the two images in row B were created using HMSS&PMO-M with 100 µL of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added; and the two images in row C were created using HMSS&PMO-L with 150 µL of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added.

[0031] Figure 11 This is a zeta potential diagram of a dual-mesoporous asymmetric silica nanoparticle-based pesticide mixture; in HMSS&PMO-S, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added is 75 µL, in HMSS&PMO-M, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added is 100 µL, and in HMSS&PMO-L, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added is 150 µL; HMSS&PMO-MAT-EMA is a nanoparticle-based pesticide mixture loaded with MAT and EMA; in HMSS&PMO-MAT-EMA-S, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added is 75 µL, and in HMSS&PMO-MAT-EMA-M, the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added is 100 µL. The amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added to HMSS&PMO-MAT-EMA-L is 150 µL;

[0032] Figure 12The insecticidal toxicity of dual-mesoporous asymmetric silica nanoparticle-based pesticides was evaluated. Concrol served as the control group, HMSS&PMO-MAT-EMA was a nanoparticle-based pesticide loaded with MAT and EMA, and MAT-EMA was a mixture of MAT and EMA. Figure A shows the toxicity of HMSS&PMO-MAT-EMA and MAT-EMA against *Trichoderma gracilis* at a concentration of 2 mg / L. Figure B compares the toxicity of HMSS&PMO-MAT-EMA and MAT-EMA against *Trichoderma gracilis* at concentrations of 0.3 mg / L and 0.6 mg / L after 72 h. Figure C shows the toxicity of HMSS&PMO-MAT-EMA and MAT-EMA against *Pteris vittata* at a concentration of 2 mg / L. Figure D shows the toxicity of HMSS&PMO-MAT-EMA and MAT-EMA against *Pteris vittata* at concentrations of 0.3 mg / L and 0.6 mg / L after 72 h. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings.

[0034] Example 1

[0035] 1. Preparation of dual-mesoporous asymmetric silica nanopesticide carriers:

[0036] See Figure 1 This invention relates to a method for preparing dual-mesoporous asymmetric silica nanopesticide carriers, comprising the following steps;

[0037] 1) Add 10 mL of pure water, 69.4 mL of ethanol and 1.6 mL of ammonia to 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 12000 rpm for 20 min. Wash three times and collect the precipitate to obtain nanoporous silica (MSNs) precipitate. Redisperse and dissolve the precipitate in 10 mL of pure water to obtain an aqueous solution of MSNs.

[0038] 2) Dissolve 60 mg of triethanolamine and 6 g of hexadecyltrimethylammonium chloride in 60 mL of pure water. Stir at 25 °C for 1 h, then add 10 mL of MSNs aqueous solution, and continue to add 0.45 mL of tetraethyl orthosilicate (0.64% by volume). Heat to 80 °C and react for 1 h. Cool to 50 °C, then add 2.12 nmol of anhydrous sodium carbonate (303000000:11) and stir for 30 min. Centrifuge at 12000 rpm for 20 min, wash three times, collect the precipitate, and dry to obtain hollow mesoporous silica HMSS.

[0039] 3) Add 150 mg HMSS to a mixed solution containing 5 mL ethanol, 75 mL pure water, 150 mg cetyltrimethylammonium bromide and 1.8 mL ammonia, stir at 30 °C for 0.5 h, add 75 μL, 100 μL and 150 μL of bis-[3-(trimethoxysilyl)propyl]ethylenediamine respectively, react for 3 h, centrifuge at 12000 rpm for 20 min, wash 3 times and collect the precipitate.

[0040] 4) The precipitate was added to a mixed solution containing 0.5 mL hydrochloric acid and 30 mL ethanol, stirred at 300 rpm for 4 h, and repeated 3 times. The template was removed and dried to obtain the nano-pesticide carrier HMSS&PMO.

[0041] 2. Characterization tests of HMSS & PMO:

[0042] The structural characteristics, uniformity, and water dispersibility of HMSS&PMO prepared according to the above method were tested. When bis-[3-(trimethoxysilyl)propyl]ethylenediamine was added in amounts of 75 μL, 100 μL, and 150 μL, the prepared HMSS&PMOs were defined as HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L, respectively. The results are as follows: Figure 2 , 3 As shown in the transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images, the prepared nanoparticles consist of spherical HMSS and rod-shaped PMOs, exhibiting a uniform asymmetric structure, uniform particle size, and good dispersibility. The HMSS has a hollow internal structure, and the length of the PMOs gradually increases with the addition of bis-[3-(trimethoxysilyl)propyl]ethylenediamine. Figure 4 As shown, the particle size of HMSS & PMO gradually increases with the increase of the amount of bis-[3-(trimethoxysilyl)propyl]ethylenediamine added.

[0043] like Figure 5 , 6 As shown, the nitrogen adsorption-desorption isotherm and pore size distribution revealed that HMSS&PMO exhibits a typical type IV curve with an H3 hysteresis loop. HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L all possess a dual mesoporous structure, with pore sizes of 2.0 nm / 3.0 nm, 2.1 nm / 3.6 nm, and 2.2 nm / 4.0 nm, respectively.

[0044] 3. Performance testing of HMSS & PMO

[0045] 1) Measurement of leaf retention and contact angle

[0046] Corn leaves and lamb's quarters leaves were punched into small discs of equal area using a 1 cm diameter punch. The corn leaves (small discs) and lamb's quarters leaves (small discs) were treated with 1 mg / L HMSS&PMO-S aqueous solution, 1 mg / L HMSS&PMO-M aqueous solution, and 1 mg / L HMSS&PMO-L aqueous solution, respectively. Leaf surface retention and contact angle were investigated and compared with the pure water treatment group. The results of leaf surface retention are shown below. Figure 7 As shown, the retention amounts of HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L on hydrophilic corn were significantly higher than those in the water-treated control group, reaching 14–15 mg / cm². For hydrophobic lamb's quarters leaves, with increasing addition of bis-[3-(trimethoxysilyl)propyl]ethylenediamine, the length and specific gravity of the hydrophobic PMO in HMSS&PMO gradually increased, leading to a gradual increase in its retention on vegetables. HMSS&PMO-L exhibited the highest retention (close to 10 mg / cm²), significantly superior to the water-treated group.

[0047] Contact angle results as follows Figure 8 As shown, the contact angles of HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L on corn and lamb's quarters leaves were all smaller than those of the water-treated control group. HMSS&PMO, as a pesticide carrier, is beneficial for adhesion and spreading on plant leaves. With increasing amounts of bis-[3-(trimethoxysilyl)propyl]ethylenediamine, the contact angles of HMSS&PMO on corn and lamb's quarters leaves gradually decreased. These experiments demonstrate that by adjusting the amounts of HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L, different HMSS&PMO formulations can be prepared, making them suitable for plant leaves with different physicochemical properties.

[0048] 2) Analysis of insect body wall penetration and plant systemicity

[0049] Healthy, uniformly sized fourth-instar larvae of the fall armyworm were selected and their body walls were treated with the fluorescent dye FITC loaded with HMSS&PMO-S, HMSS&PMO-M, or HMSS&PMO-L using a spot treatment method. After treatment, the larvae were placed in an incubator at 25±1℃ and 40% relative humidity for 3 hours. Longitudinal sections of the larvae with a thickness of 10 μm were prepared using cryosectioning and observed under a fluorescence confocal microscope (excitation wavelength 488 nm, emission wavelength 520 nm). Results are as follows: Figure 9As shown, the fluorescently labeled HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L all exhibit significant green fluorescence within the insect, indicating that HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L can overcome the natural barrier of the insect's epidermis and efficiently penetrate the body wall of the fall armyworm. Using HMSS&PMO as a carrier to load pesticides helps improve the delivery efficiency and systemic properties of pesticides.

[0050] Healthy, uniformly growing maize seedlings (three-leaf stage) were selected and randomly divided into two groups. HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L, loaded with the fluorescent dye FITC, were evenly applied to the surface of the terminal leaves. After treatment, the maize plants were cultured at 25±1℃ for 6 hours under a photoperiod of 16h / 8h. Fluorescence imaging of the maize plants was performed using a biomolecular imaging system. The results are as follows: Figure 10 As shown, after treating maize leaves with fluorescently labeled HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L, significant green fluorescence was observed in different parts of the maize plant, indicating that HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L all exhibit significant systemic and top-down transport delivery capabilities. Using HMSS&PMO as a carrier to load pesticides helps improve the absorption and distribution of pesticides on crop leaves.

[0051] Example 2

[0052] 1. Preparation of nano-compound pesticides using HMSS & PMO as carriers

[0053] 1) Loading of biopesticides

[0054] Taking the pesticide matrine (MAT) supported by HMSS&PMO as an example, nano-matrine (HMSS&PMO-MAT) was prepared.

[0055] 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 min, 30-3 mg of the biopesticide was added, and the mixture was stirred at 4 ℃ for 24 h for loading. Afterwards, the mixture was centrifuged, washed, and dried to obtain the nanopesticide HMSS&PMO-MAT. The biopesticide was a microbial pesticide, dsRNA, polypeptide, or protein.

[0056] 2) Preparation of nano-component pesticides

[0057] Taking the pesticide emamectin benzoate (EMA) further loaded in the HMSS&PMO-MAT mode as an example, a nano-mixed pesticide (HMSS&PMO-MAT-EMA) was prepared.

[0058] The nano-biological pesticides prepared in the above steps were loaded with the model pesticide emamectin benzoate at a mass ratio of 1-10:1. 30 mg of the nano-biological pesticide prepared in step 1) was dissolved in 60 mL of methanol (or acetone, dimethylformamide, depending on the pesticide's solubility characteristics), and ultrasonically treated for 10 min. Then, 30-3 mg of chemical pesticide was added, and the mixture was stirred at room temperature for 24 h for loading. Afterwards, the mixture was centrifuged, washed, and dried to obtain the nano-mixed pesticides HMSS&PMO-MAT-EMA-S, HMSS&PMO-MAT-EMA-M, and HMSS&PMO-MAT-EMA-L.

[0059] 2. Characterization tests of nano-component pesticides MSS & PMO-MAT-EMA

[0060] 1) Zeta potential test

[0061] The zeta potentials of HMSS&PMO-S, HMSS&PMO-M, HMSS&PMO-L nanocarriers and their corresponding nano-mixed pesticides HMSS&PMO-MAT-EMA-S, HMSS&PMO-MAT-EMA-M, and HMSS&PMO-MAT-EMA-L were tested. The results are as follows: Figure 11 As shown, the Zeta potential distributions of HMSS&PMO-S, HMSS&PMO-M, and HMSS&PMO-L are 10.08 mV, 7.73 mV, and 0.28 mV, respectively, all carrying a positive charge. After loading MAT and EMA to form HMSS&PMO-MAT-EMA-S, HMSS&PMO-MAT-EMA-M, and HMSS&PMO-MAT-EMA-L, the potentials decrease to −13.54 mV, −2.96 mV, and −12.2 mV, respectively. The loading of the two pesticides causes a shift in the Zeta potential from positive to negative, indicating that MAT and EMA were successfully loaded.

[0062] 2) Drug loading analysis

[0063] The loading amounts of the nano-compound pesticides HMSS&PMO-MAT-EMA-S, HMSS&PMO-MAT-EMA-M, and HMSS&PMO-MAT-EMA-L prepared in Example 2 on two pesticides (MAT and EMA) were tested. Loading rates and pesticide loading amounts were obtained by high-performance liquid chromatography (HPLC). For MAT determination, the mobile phase was acetonitrile + ethanol + 3% phosphoric acid solution = 84 + 6 + 6 (v / v), mobile phase flow rate: 1.0 mL / min, column temperature: 30 (+0.5) °C, UV detection wavelength: 220 nm, injection volume: 10 μL, and column: XDB C18 column. For EMA determination, the mobile phase was methanol + water = 92 + 8 (v / v), mobile phase flow rate: 1.0 mL / min, column temperature: 30 (+0.5) °C, UV detection wavelength: 240 nm, injection volume: 10 μL, and column: XDB C18 column. The results are shown in Table 1. The pesticide loading capacities of HMSS&PMO-MAT-EMA-S for MAT and EMA were 49.25% and 4.82%, respectively; those of HMSS&PMO-MAT-EMA-M for MAT and 10.87%; and those of HMSS&PMO-MAT-EMA-L for MAT and 35.48%, respectively. The HMSS&PMO pesticide nanocarriers achieved co-loading of two pesticides with different physicochemical properties, with total pesticide loading capacities reaching 54.07%, 54.66%, and 54.07%, respectively.

[0064] Table 1 Drug loading of MAT and EMA in HMSS&PMO-MAT-EMA

[0065] 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

[0066] 3. Insecticide toxicity test

[0067] Based on the optimal retention and smallest contact angle of HMSS&PMO-L on corn and lamb's quarters, HMSS&PMO-L was selected as the carrier to load MAT and EMA. The resulting nano-mixed pesticide MSS&PMO-MAT-EMA was tested for its insecticidal toxicity against the third instar larvae of two lepidopteran pests (fall armyworm and grass moth) using the leaf immersion method. Leaves were immersed in HMSS&PMO-MAT-EMA aqueous solutions at pesticide 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, then removed, air-dried, and fed to the pests. The mortality of the test insects was observed after 72 hours, and the results were analyzed using PoloPlus software. The indoor toxicity results are shown in Tables 2 and 3. The LC50 results of the nanopesticides (HMSS&PMO-MAT-EMA, HMSS&PMO-MAT, HMSS&PMO-EMA) prepared using HMSS&PMO nanopesticide carriers against two lepidopteran pests are presented. 50 The values ​​were all significantly higher than those of the pesticide technicals (MAT-EMA, MAT, EMA), demonstrating that HMSS&PMO, as a nanopesticide carrier, has the advantage of enhancing the insecticidal toxicity of pesticides. Furthermore, the LC50 values ​​of HMSS&PMO-MAT-EMA against fall armyworm larvae... 50 The value (0.224 mg / L) is lower than that of MAT-EMA physically mixed pesticides (LC50). 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 LC50 of prairie borer larvae 50 The value (0.338 mg / L) was also lower than that of MAT-EMA physically mixed pesticides (LC50). 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 the HMSS&PMO-MAT-EMA nano-compound pesticide has higher insecticidal toxicity compared to traditional physically mixed pesticides and nano-single-loaded pesticides.

[0068] Table 2. Toxicity of HMSS & PMO-MAT-EMA to Fall Armyworm

[0069] 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

[0070] Table 3. Toxicity of HMSS & PMO-MAT-EMA to the grassland moth

[0071] 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

[0072] Using third-instar fall armyworm larvae and fall armyworm larvae as model insects, HMSS & PMO-MAT-EMA and MAT-EMA mixtures at concentrations of 0.3 mg / L, 0.6 mg / L, and 2 mg / L were applied to the fall armyworm and fall armyworm, and the mortality rates of the test insects within 96 hours were compared. The results are as follows: Figure 12 As shown in Figure A, the toxic effects of HMSS & PMO-MAT-EMA and MAT-EMA on the grassland moth at a concentration of 2 mg / L were investigated, with mortality rates at 12h, 24h, 36h, 48h, 60h, 72h, 84h, and 96h compared to the control group; Figure B compares the toxic effects of HMSS & PMO-MAT-EMA and MAT-EMA on the grassland moth at concentrations of 0.3 mg / L and 0.6 mg / L for 72h; Figure C shows the toxic effects of 2 mg / L HMSS & PMO-MAT-EMA and MAT-EMA on the grassland moth. The toxic effects of HMSS&PMO-MAT-EMA and MAT-EMA on fall armyworm at concentrations of 0.3 mg / L were investigated, with mortality rates observed at 12 h, 24 h, 36 h, 48 h, 60 h, 72 h, 84 h, and 96 h. Figure D shows the toxic effects of HMSS&PMO-MAT-EMA and MAT-EMA on fall armyworm at concentrations of 0.3 mg / L and 0.6 mg / L for 72 h. The results indicate that the lethality of the nano-component pesticide HMSS&PMO-MAT-EMA against both lepidopteran pests within 96 h was significantly higher than that of the same concentration of MAT-EMA mixed technical material, demonstrating that HMSS&PMO, as a nano-pesticide carrier, can enhance the rapid action and activity of pesticides.

[0073] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a dual-mesoporous asymmetric silica nanopesticide carrier, characterized in that... Includes the following steps: 1) Add pure water, ethanol and ammonia water in a volume ratio of 50:347:8 to a 500ml round bottom flask. Stir at 25℃ and 250rpm for 10min, then add tetraethyl orthosilicate and react for 1h. The volume ratio of tetraethyl orthosilicate to ammonia water is 5:

4. Centrifuge at 12000rpm for 20min, wash 3 times and collect the precipitate to obtain nanoporous silica MSNs precipitate. Redisperse and dissolve the nanoporous silica MSNs precipitate in pure water to obtain an MSNs 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, then add MSNs aqueous solution, and continue to add tetraethyl orthosilicate (0.64% by volume). Heat to 80°C and react for 1 hour. Cool to 50°C, then add anhydrous sodium carbonate at a solute ratio of 303000000:11 and stir for 30 minutes. Centrifuge at 12000 rpm for 20 minutes, wash 3 times, collect the precipitate, and dry to obtain hollow mesoporous silica HMSS. 3) A mixed solution was prepared by mixing ethanol, pure water, hexadecyltrimethylammonium bromide and ammonia, wherein the volume ratio of ethanol, pure water and ammonia was 25:375:9, and the mass-volume ratio of hexadecyltrimethylammonium bromide to pure water in the mixed solution was 2:1 mg / mL. HMSS was added to the mixed solution, and the mass ratio of HMSS to hexadecyltrimethylammonium bromide in the mixed solution was 1:

1. The mixture was stirred at 30℃ for 0.5 h, and then bis-[3-(trimethoxysilyl)propyl]ethylenediamine was added, wherein the volume ratio of bis-[3-(trimethoxysilyl)propyl]ethylenediamine to pure water in the mixed solution was 1:

500. After reacting for 3 h, the mixture was centrifuged at 12000 rpm for 20 min, washed 3 times, and the precipitate was collected. 4) Prepare a mixed solution by mixing hydrochloric acid and ethanol at a volume ratio of 1:

60. Add the precipitate obtained in step 3) to the mixed solution and stir at 300 rpm for 4 hours. Repeat 3 times, remove the template, and dry to obtain the nano-pesticide carrier HMSS&PMO.

2. The dual-mesoporous asymmetric silica nanopesticide carrier prepared by the preparation method according to claim 1.

3. A method for preparing a nano-compound pesticide, characterized in that... Includes the following steps: 1) Weigh the dual mesoporous asymmetric silica nanopesticide carrier according to claim 2 and dissolve it in pure water. After ultrasonic treatment for 10 min, add the biological pesticide. The mass ratio of the dual mesoporous asymmetric silica nanopesticide carrier to the biological pesticide is 1-10:

1. Stir at 4℃ for 24 h to load the pesticide. Then centrifuge, wash and dry to obtain nano-biological pesticide. 2) Weigh the nano-biological pesticide obtained in step 1), dissolve it in a solvent, treat it with ultrasound for 10 minutes, add chemical pesticide, the mass ratio of the nano-biological pesticide to the chemical pesticide is 1-10:1, stir at room temperature for 24 hours to load, and then centrifuge, wash and dry to obtain nano-mixed pesticide.

4. The method for preparing a nano-mixed pesticide according to claim 3, characterized in that: The solvent is methanol, acetone or dimethylformamide.

5. The nano-mixed pesticide prepared by the preparation method according to claim 3.

Images