Nanometer pesticide with bidirectional conveying function as well as preparation method and application of nanometer pesticide

Abstract

The invention belongs to the field of pesticide chemistry, and relates to preparation of nano-pesticides, in particular to a nano-pesticide with a two-way conveying function and a preparation method and application of the nano-pesticide. MIL-101 (FeIII, CuII) is used as a pesticide carrier, non-systemic fludioxonil pesticide molecules are loaded in a solution, and then the MIL-101 (CuII, FeIII) MOF nanoparticles loaded with the fludioxonil pesticide are encapsulated with chitosan oligosaccharide in the aqueous solution. The nanometer pesticide preparation prevents fludioxonil pesticide molecules from being released in a solvent in advance, the retention amount of the fludioxonil pesticide on leaf surfaces is increased, the lasting pesticide effect of the fludioxonil pesticide molecules in target crops is improved, the nanometer pesticide preparation is environmentally friendly, and the purposes of disease control, agricultural yield increase and quality improvement are achieved. The nano-carrier provided by the invention can be bidirectionally conveyed in crops through leaf surface pores or root hairs, so that the conveying efficiency of fludioxonil pesticide molecules is improved, and the application scene of the nano-carrier is widened.

Description

Technical Field

[0001] This invention belongs to the field of pesticide chemistry and relates to the preparation of nanopesticides. Background Technology

[0002] In recent years, metal-organic frameworks (MOFs), formed by the coordination of organic bridging ligands with inorganic metal ions or metal-oxygen clusters, have attracted much attention in the field of nanomedicine delivery. As a drug delivery carrier, porous MOF nanomaterials, compared with inorganic nanomaterials such as molecular sieves or porous carbon nanomaterials, have the following characteristics: 1) The variety of organic bridging ligands allows MOFs to possess high specific surface area and porosity, as well as different pore sizes. Thus, selecting suitable MOF materials can yield high drug loading; 2) The structural building blocks of MOFs can be different metal ions or metal-oxygen clusters. Organic bridging ligands have different structures, shapes, and sizes, exhibiting designability and diversity. This allows for the assembly of MOF materials with specific functions based on the microenvironment of target biological tissues or organs; 3) Many organic ligands, due to their length or the presence of σ single bonds, possess a certain degree of flexibility, and the pore size can be adjusted. Thus, the pore size can be adjusted to regulate the controlled release of the loaded drug; 4) Unlike purely inorganic porous materials, porous MOF materials can possess a wide variety of surface physicochemical properties. Therefore, due to the structural diversity of organic bridging ligands, specific pore and surface structures can be designed as needed; 5) Coordination bonds are reversible, and organic bridging ligands can contain or modify various reactive functional groups, endowing the metal center and organic bridging ligands of MOF materials with a certain degree of modifiability. Thus, through functional modification, the structure and properties of the inner and outer surfaces of MOF materials can be altered and improved; 6) The reversibility of coordination bonds makes MOF materials degradable in vivo, avoiding potential toxic accumulation.

[0003] As drug carriers, Fe-MOF or Cu-MOF are easily applied to nanomedicine delivery systems due to their simple preparation process, low raw material cost, non-toxicity, environmental friendliness, and good biocompatibility. Fe-MOF or Cu-MOF have been used to construct multifunctional nanomedicine delivery materials (such as the MIL and PCN series) and have demonstrated good drug delivery performance and therapeutic effects (e.g., application CN 111011371 A). However, current research on these nanomaterials is mainly focused on the pharmaceutical field, and their direct application in medicine is difficult due to the inherent stability of Fe-MOF or Cu-MOF and the complexity of biological tissues or organs. Non-systemic pesticides (such as fludioxonil) are difficult to deliver and transfer within target crops, severely limiting their application efficiency and application scenarios. Therefore, exploring the efficacy and delivery applications of nanopesticides loaded with non-systemic pesticides is of great significance for achieving high-quality and high-yield crops. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a nano-pesticide with bidirectional delivery function, its preparation method, and its application.

[0005] The technical solution of this invention is implemented as follows: A method for preparing a nanopesticide with bidirectional delivery function, comprising the following steps: (1) MIL-101(Cu II Fe III After mechanically stirring MOF and pesticide nitriles in a solvent for a certain period of time, pesticide molecules are loaded into MIL-101 (Cu II Fe III In the channels of the MOF, unloaded pesticide molecules are removed by centrifugation and washing to obtain the pesticide-loaded MIL-101 (Cu). II Fe III MOF material. Preferably, the MIL-101(Cu) material. II Fe III The size of the nanoparticles is less than 300 nm; (2) The drug-loaded MIL-101(Cu) obtained in step (1) II Fe III MOF material was dispersed in an aqueous phase, and then chitosan oligosaccharide was added to encapsulate MIL-101 (Cu). II Fe III MOF surface. MIL-101 (Cu) drug-loaded surface. II Fe III Unsaturated Fe on the surface of MOF materials III or Cu IIThe chitosan oligosaccharide is coordinated with the nanoparticles, causing the oligosaccharide to assemble onto the surface of the nanoparticles. The nanoparticles are then centrifuged, washed, and dried. Preferably, the aqueous phase is deionized water.

[0006] The MOF material is prepared by synthesizing an organic ligand and an inorganic metal salt via a solvothermal method; the organic ligand is 2-amino-1,4-terephthalic acid or 1,4-terephthalic acid; the inorganic metal salt is FeCl3 and CuCl2; the molar ratio of the organic ligand, iron salt and copper salt is 9:6:4.

[0007] Preferably, the MIL-101(Cu) II Fe III MOF nanoparticles have a diameter of less than 300 nm.

[0008] Preferably, the solvent is acetone, ethanol, or methanol, and the pesticide compound is fludioxonil; the concentration of the fludioxonil is 6 mg / mL. The MIL-101(Cu II Fe III The concentration of nanoparticles was 3 mg / mL.

[0009] Preferably, the concentration of chitosan oligosaccharide used for encapsulation is 1-3 mg / mL, and the MIL-101(Cu) II Fe III The concentration of nanoparticles is 1 mg / mL.

[0010] More preferably, the MIL-101(Cu II Fe III The preparation method is as follows: FeCl3·6H2O and CuCl2·2H2O in a molar ratio of 3:2 and an organic ligand are dissolved in dimethylformamide (DMF) solution, placed in a reaction vessel, reacted at 100 °C for 12 h, and then centrifuged, washed and vacuum dried to obtain the product; the organic ligand is 2-amino-1,4-terephthalic acid or 1,4-terephthalic acid.

[0011] More preferably, the amount of FeCl3·6H2O is 6 mmol, the amount of CuCl2·2H2O is 4 mmol, the amount of 2-amino-1,4-terephthalic acid or 1,4-terephthalic acid used is 9 mmol, and the volume of DMF solvent used is 70 mL.

[0012] This invention also provides MIL-101 (Cu) encapsulated with chitosan oligosaccharides prepared by the above method. II Fe III MOF nanopesticides.

[0013] The present invention also provides the above-mentioned chitosan oligosaccharide-encapsulated MIL-101 (Cu II Fe III MOF nanopesticides' controlled release performance, using MIL-101(Cu) II Fe III MOF nanopesticides are placed in a medium, and pesticide release can be controlled by controlling environmental factors in the medium. These environmental factors include one or more of the following: different concentrations of phosphate, different concentrations of sodium ethylenediaminetetraacetate (EDTA·Na), and different pH values.

[0014] The performance of the nano-pesticides in this application is demonstrated in their application in the preparation of agents to control Botrytis cinerea on tomato leaves, and in their compatibility with the prepared MIL-101(Cu II Fe III MOF nanomaterials have a synergistic effect against Botrytis cinerea.

[0015] And its application in preparing a product that promotes bidirectional delivery of pesticides within tomato plants.

[0016] Furthermore, the bidirectional transmission refers to: ① Nanopesticides are absorbed through the stomata on the leaves of tomato plants and then transferred to the stems and roots; ② Nanopesticides are absorbed by the root hairs of tomato plants and then transferred to the stems and leaves.

[0017] The present invention has the following beneficial effects: 1. The MIL-101 (Cu) used in this invention II Fe III Nanoparticles possess advantages such as being non-toxic, environmentally friendly, readily degradable in plants or animals, non-aggregating, having a large specific surface area, large pore volume, and flexible and diverse structures. The solvent described in this invention can effectively dissolve the pesticide fludioxonil molecules, and the solvent does not affect MIL-101 (Cu II Fe III The morphology and crystal structure of the nanoparticles remain stable and well maintained.

[0018] 2. In this invention, the encapsulation membrane formed by chitosan oligosaccharides can effectively encapsulate MIL-101 (Cu) in aqueous solution. II ,Fe III The Cu-Fe-MOF prepared from bimetallic copper and iron nanoparticles is non-toxic and biodegradable, with tunable pore size (reaching 4.7 nm), large specific surface area, and high pore volume (reaching 2 nm). . 3 cm 3 Features include high drug loading rate, structural flexibility, and diversity.

[0019] 3. In this invention, MIL-101(Cu II Fe III Encapsulating the surface of nanoparticles with chitosan oligosaccharides effectively prevents the release of the loaded pesticide fludioxonil molecules, avoiding premature leakage during transportation and storage. The MIL-101(Cu) provided by this invention... II Fe III MOF nanopesticide formulations achieve multi-responsive pesticide release performance in acidic pH, phosphate, and EDTA·Na, and have great application prospects in the field of nanopesticides.

[0020] 4. In this invention, MIL-101(Cu II Fe III MOF nanopesticide formulations have bidirectional delivery capabilities within tomato plants. The MIL-101(Cu) formulation provided by this invention is used... II Fe III MOF nanopesticide formulations can achieve the delivery performance of loaded non-systemic pesticides in target plants, broadening the application efficiency and scenarios of non-systemic pesticides. They are non-toxic, environmentally friendly, biocompatible, easily degradable, have high pesticide loading rates, and have synergistic effects with the loaded pesticides. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 MIL-101 (Cu) prepared in Example 1 II Fe III (a) SEM and (b) TEM images of MOF nanoparticles and MIL-101(Cu) II Fe III (c) SEM and (d) TEM images of chitosan oligosaccharide nanoparticles.

[0023] Figure 2 MIL-101 (Cu) prepared in Example 1 II Fe III ), fludioxonil@MIL-101 (Fe III ) and fludioxonil@MIL-101 (Fe III XRD of chitosan oligosaccharide nanoparticles.

[0024] Figure 3 MIL-101 (Cu) prepared in Example 1 II Fe III ), fludioxonil@MIL-101 (Cu II Fe III ) and fludioxonil@MIL-101 (Cu II Fe III (a) Nitrogen adsorption-desorption isotherms and (b) pore size distribution of chitosan oligosaccharide nanoparticles.

[0025] Figure 4 The fludioxonil@MIL-101(Cu) prepared in Example 1 II Fe III Controlled release curves of pesticides in response to acidic pH stimulation in chitosan oligosaccharide nanopesticide formulations.

[0026] Figure 5 The fludioxonil@MIL-101(Cu) prepared in Example 1 II Fe III )@Pesticide controlled release curves of chitosan oligosaccharide nanopesticide formulations in response to phosphate stimulation.

[0027] Figure 6 The fludioxonil@MIL-101(Cu) prepared in Example 1 II Fe III Controlled release curves of pesticides in response to EDTA·Na stimulation in chitosan oligosaccharide nanopesticide formulations.

[0028] Figure 7 The fludioxonil@MIL-101(Cu) prepared in Example 1 II Fe III The in vitro antibacterial effect of chitosan oligosaccharide nanopesticide formulations.

[0029] Figure 8 The fludioxonil@MIL-101(Cu) prepared in Example 1 II Fe III The effect of chitosan oligosaccharide nano-pesticide formulation on the control of gray mold in tomatoes.

[0030] Figure 9 The FITC fluorescently labeled FITC@MIL-101(Cu) prepared in Example 1 II Fe III Chitosan oligosaccharide nanoparticles are absorbed through stomata or root hairs on the leaves of tomato plants and then transported bidirectionally within the plant. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following experimental examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0033] This application discloses a method for preparing a nanopesticide with bidirectional delivery function, the steps of which are as follows: (1) Organic ligands and mixed inorganic metal salts were subjected to a solvothermal reaction, followed by washing, reflux activation, and drying to obtain MIL-101 (Cu II Fe III MOF materials; (2) MIL-101 (Cu) in step (1) II Fe III MOF material and pesticide were mixed in a solvent, and then centrifuged and freeze-dried to obtain pesticide-loaded MIL-101 (Cu). II Fe III MOF; (3) The drug-loaded MIL-101 (Cu) from step (2) is loaded with the drug. II Fe III MOF was dispersed in water, then chitosan oligosaccharide was added, and the reaction was stirred at room temperature. After centrifugation, washing, and freeze-drying, pesticide @MIL-101(Cu) was obtained. II Fe III Chitosan oligosaccharide nanopesticides are nanopesticides with bidirectional delivery function.

[0034] In step (1) above, the organic ligand is 2-amino-1,4-terephthalic acid or 1,4-terephthalic acid; the mixed inorganic metal salt includes iron and copper salts; the molar ratio of the organic ligand, iron salt, and copper salt is 9:6:4. The temperature of the above solvothermal reaction is 100°C. o C. The time is 12 h; the particle size of the pesticide in step (2) is smaller than MIL-101 (Cu II Fe III The diameter of the pores in MOF materials; MIL-101 (Cu II Fe III The mass ratio of MOF material to pesticide is 1:2; in step (3), the pesticide MIL-101 (Cu) is loaded. II Fe IIIThe concentration of MOF was 1 mg / mL; the concentration of chitosan oligosaccharide was 1-3 mg / mL.

[0035] In principle, the pesticides in this application, as long as they meet the requirement that the pesticide size is smaller than MIL-101 (Cu II Fe III The channels of the MOF allow for the loading of pesticide fludioxonil molecules into MIL-101 (Cu) through stirring. II Fe III It can be placed in the channels of MOF; the following examples The performance of nano-pesticides was studied using fludioxonil as an example. Example 1 The preparation method of a nano-pesticide with bidirectional delivery function in this embodiment includes the following steps: (1) 2-Amino-1,4-terephthalic acid or terephthalic acid (9 mmol), FeCl3·6H2O (6 mmol), and CuCl2·2H2O (4 mmol) were dissolved in 70 mL of DMF. After mixing thoroughly, the mixture was transferred to a stainless steel reactor and placed in an oven at 100 °C for 12 h. After cooling to room temperature, the mixture was washed three times with water and ethanol, and then activated by reflux with ethanol for 24 h. The nanoparticles were collected by centrifugation and dried in a vacuum drying oven at 60 °C to obtain MIL-101 (Cu II ,Fe III Nanoparticles.

[0036] (2) MIL-101(Cu II Fe III Nanoparticles were dispersed in an acetone solution of the pesticide fludioxonil, resulting in a fludioxonil concentration of 6 mg / mL, MIL-101 (Cu II Fe III The concentration of nanoparticles was 3 mg / mL. After stirring at room temperature for 24 h, centrifugation, and freeze-drying, fludioxonil@MIL-101(Cu) was obtained. II Fe III Nanoparticles.

[0037] (3) Take 1 mg / mL of fludioxonil@MIL-101(Cu II Fe III Nanoparticles were dispersed in a 1-3 mg / mL chitosan oligosaccharide aqueous solution, stirred at room temperature for 24 h, centrifuged, and washed four times with deionized water and ethanol to remove unreacted chitosan oligosaccharides. The mixture was then freeze-dried to obtain chitosan oligosaccharide-encapsulated fludioxonil@MIL-101(Cu) II Fe III Chitosan oligosaccharide nanopesticides.

[0038] Figure 1 For MIL-101 (Cu II Fe III (a) SEM and (b) TEM images of nanoparticles and MIL-101(Cu) encapsulated with chitosan oligosaccharides. II Fe III (c) SEM and (d) TEM images of nanoparticles: as shown Figure 1 As shown, the nanoparticles obtained in step (1) have a relatively uniform morphology and size, all of which are octahedral in shape and have a diameter of less than 300 nm. After encapsulation with chitosan oligosaccharide, their morphology remains almost unchanged, and the thickness of chitosan oligosaccharide is 3 to 8 nm.

[0039] Figure 2 and Figure 3 These are the prepared MIL-101(Cu) II Fe III ), fludioxonil@MIL-101 (Cu II Fe III ) and fludioxonil@MIL-101 (Fe III Thermogravimetric analysis, nitrogen adsorption-desorption isotherms, and pore size distribution of chitosan oligosaccharide nanoparticles. Figure 2 and 3 It is known that the pesticide fludioxonil molecule has been successfully loaded into MIL-101 (Cu II Fe III The nanoparticles have pores inside, and chitosan oligosaccharide molecules have been successfully encapsulated in MIL-101 (Cu II Fe III Nanoparticle surface.

[0040] Example 2 The preparation method of a nano-pesticide with bidirectional delivery function in this embodiment includes the following steps: (1) 2-Amino-1,4-terephthalic acid or terephthalic acid (9 mmol), FeCl3·6H2O (6 mmol), and CuCl2·2H2O (4 mmol) were dissolved in 70 mL of DMF. After mixing thoroughly, the mixture was transferred to a stainless steel reactor and placed in an oven at 90 °C for 15 h. After cooling to room temperature, the mixture was washed three times with water and ethanol, and then activated by reflux with ethanol for 24 h. The nanoparticles were collected by centrifugation and dried in a vacuum drying oven at 60 °C to obtain MIL-101 (Cu II Fe III Nanoparticles.

[0041] (2) MIL-101(Cu II Fe IIINanoparticles were dispersed in an acetone solution of the pesticide fludioxonil, resulting in a fludioxonil concentration of 9 mg / mL, MIL-101 (Cu II Fe III The concentration of nanoparticles was 3 mg / mL. After stirring at room temperature for 24 h, centrifugation, and freeze-drying, fludioxonil@MIL-101(Cu) was obtained. II Fe III Nanoparticles.

[0042] (3) Take 1 mg / mL of fludioxonil@MIL-101(Cu II Fe III Nanoparticles were dispersed in a 2 mg / mL chitosan oligosaccharide aqueous solution, stirred at room temperature for 24 h, centrifuged, and washed four times with deionized water and ethanol to remove unreacted chitosan oligosaccharides. The mixture was then freeze-dried to obtain chitosan oligosaccharide-encapsulated fludioxonil@MIL-101(Cu) II Fe III Chitosan oligosaccharide nanopesticides.

[0043] Example 3 The preparation method of a nano-pesticide with bidirectional delivery function in this embodiment includes the following steps: (1) 2-Amino-1,4-terephthalic acid or terephthalic acid (9 mmol), FeCl3·6H2O (6 mmol), and CuCl2·2H2O (4 mmol) were dissolved in 70 mL of DMF. After mixing thoroughly, the mixture was transferred to a stainless steel reactor and placed in an oven at 95 °C for 16 h. After cooling to room temperature, the mixture was washed three times with water and ethanol, and then activated by reflux with ethanol for 24 h. The nanoparticles were collected by centrifugation and dried in a vacuum drying oven at 60 °C to obtain MIL-101 (Cu II Fe III Nanoparticles.

[0044] (2) MIL-101(Cu II Fe III Nanoparticles were dispersed in an acetone solution of the pesticide fludioxonil, resulting in a fludioxonil concentration of 12 mg / mL, MIL-101 (Cu II Fe III The concentration of nanoparticles was 3 mg / mL. After stirring at room temperature for 24 h, centrifugation, and freeze-drying, fludioxonil@MIL-101(Cu) was obtained. II Fe III Nanoparticles.

[0045] (3) Take 1 mg / mL of fludioxonil@MIL-101(Cu II FeIII Nanoparticles were dispersed in a 3 mg / mL chitosan oligosaccharide aqueous solution, stirred at room temperature for 24 h, centrifuged, and washed four times with deionized water and ethanol to remove unreacted chitosan oligosaccharides. The mixture was then freeze-dried to obtain chitosan oligosaccharide-encapsulated fludioxonil@MIL-101(Cu) II Fe III Chitosan oligosaccharide nanopesticides.

[0046] Example 4 The preparation method of a nano-pesticide with bidirectional delivery function in this embodiment includes the following steps: (1) 2-Amino-1,4-terephthalic acid or terephthalic acid (9 mmol), FeCl3·6H2O (6 mmol), and CuCl2·2H2O (4 mmol) were dissolved in 70 mL of DMF. After mixing thoroughly, the mixture was transferred to a stainless steel reactor and placed in an oven at 93 °C for 20 h. After cooling to room temperature, the mixture was washed three times with water and ethanol, and then activated by reflux with ethanol for 24 h. The nanoparticles were collected by centrifugation and dried in a vacuum drying oven at 60 °C to obtain MIL-101 (Cu II Fe III Nanoparticles.

[0047] (2) MIL-101(Cu II Fe III Nanoparticles were dispersed in an acetone solution of the pesticide fludioxonil, resulting in a fludioxonil concentration of 15 mg / mL. MIL-101 (Cu II Fe III The concentration of nanoparticles was 3 mg / mL. After stirring at room temperature for 24 h, centrifugation, and freeze-drying, fludioxonil@MIL-101(Cu) was obtained. II Fe III Nanoparticles.

[0048] (3) Take 1 mg / mL of fludioxonil@MIL-101(Cu II Fe III Nanoparticles were dispersed in a 2.5 mg / mL chitosan oligosaccharide aqueous solution, stirred at room temperature for 24 h, centrifuged, and washed four times with deionized water and ethanol to remove unreacted chitosan oligosaccharides. The mixture was then freeze-dried to obtain chitosan oligosaccharide-encapsulated fludioxonil@MIL-101(Cu) II Fe III Chitosan oligosaccharide nanopesticides.

[0049] Example 5 The preparation method of a nano-pesticide with bidirectional delivery function in this embodiment includes the following steps: (1) 2-Amino-1,4-terephthalic acid or terephthalic acid (9 mmol), FeCl3·6H2O (6 mmol), and CuCl2·2H2O (4 mmol) were dissolved in 70 mL of DMF. After mixing thoroughly, the mixture was transferred to a stainless steel reactor and placed in an oven at 100 °C for 12 h. After cooling to room temperature, the mixture was washed three times with water and ethanol, and then activated by reflux with ethanol for 24 h. The nanoparticles were collected by centrifugation and dried in a vacuum drying oven at 60 °C to obtain MIL-101 (Cu II ,Fe III Nanoparticles.

[0050] (2) MIL-101(Cu II Fe III Nanoparticles were dispersed in an acetone solution of the pesticide fludioxonil, resulting in a fludioxonil concentration of 13 mg / mL, MIL-101 (Cu II Fe III The concentration of nanoparticles was 3 mg / mL. After stirring at room temperature for 24 h, centrifugation, and freeze-drying, fludioxonil@MIL-101(Cu) was obtained. II Fe III Nanoparticles.

[0051] (3) Take 1 mg / mL of fludioxonil@MIL-101(Cu II Fe III Nanoparticles were dispersed in a 1.5 mg / mL chitosan oligosaccharide aqueous solution, stirred at room temperature for 24 h, centrifuged, and washed four times with deionized water and ethanol to remove unreacted chitosan oligosaccharides. The mixture was then freeze-dried to obtain chitosan oligosaccharide-encapsulated fludioxonil@MIL-101(Cu) II Fe III Chitosan oligosaccharide nanopesticides.

[0052] Example of Implementation Results 1: Controlled Release Test of Pesticides 1. Weigh multiple equal amounts of fludioxonil@MIL-101 (Cu) prepared in Example 1. II Fe III The chitosan oligosaccharide nanopesticide formulation was placed in a dialysis bag and then immediately placed in a 0.1% Tween-80 ethanol and acetate buffer solution at pH 5.0. 乙醇 / v 醋酸缓冲液 In a mixed solution of (ratio 2:3), 0.2 mL samples were taken at different time intervals, and an equal volume of fresh solution (0.2 mL) was added. After dilution, the solutions were determined by HPLC.

[0053] Figure 4The corresponding acidic pH response pesticide release curves show that the pesticide release rate in the control group without any irritation was only 30.56%, almost no release; while the release rate at pH 5.0 was 55.94%, showing significant release.

[0054] 2. Weigh multiple equal amounts of fludioxonil@MIL-101 (Cu) prepared in Example 1. II Fe III The chitosan oligosaccharide nanopesticide formulation was placed in a dialysis bag and then immersed in 0.1% Tween-80 ethanol and PBS buffer solutions of different concentrations of phosphate (v). 乙醇 / v 磷酸盐缓冲液 In a mixed solution of 2:3, the determination procedure is the same as above.

[0055] Figure 5 The pesticide release curves are controlled release curves for phosphate responses of 0, 5 mM, and 10 mM. The pesticide release rate was 70.14% in 5 mM PBS and 86.15% in 10 mM PBS.

[0056] 3. Weigh multiple equal amounts of fludioxonil@MIL-101 (Cu) prepared in Example 1. II Fe III The chitosan oligosaccharide nanopesticide formulation was placed in a dialysis bag and then immersed in 0.1% Tween-80 ethanol and water at different concentrations of EDTA·Na. 乙醇 / v 水 In a 2:3 mixed solution, the determination procedure is the same as above.

[0057] Figure 6 The pesticide controlled release curves are for 0, 2 mM, and 5 mM EDTA·Na. The pesticide release rate is 76.12% at 2.0 mM and 92.44% at 5.0 mM.

[0058] Example 2 of Implementation Results: In Vitro Antibacterial Efficacy Test 0, 0.025, 0.05, 0.1, 0.2, 0.4 mg / L fludioxonil@MIL-101(Cu II Fe III Effect of chitosan oligosaccharide dispersion (solvent: a mixture of 0.1% Tween-80 ethanol and water) on the in vitro proliferation of *Botrytis cinerea*: *Botrytis cinerea* was inoculated onto culture dishes. After the colonies spread, different concentrations of fludioxonil@MIL-101 (Cu) prepared in Example 1 were added. II ,Fe III @Chitosan oligosaccharide dispersion, after incubation for different times, record the size of the colony zone. Corresponding to the technical grade fludioxonil, commercial fludioxonil suspension, and MIL-101 (Cu II Fe IIIChitosan oligosaccharide nanoparticles were used as controls.

[0059] Figure 7 a displays MIL-101 (Cu II Fe III When the concentration of chitosan oligosaccharide nanoparticles reached 96 h, the inhibition of colony zone was not significant at different time periods. Figure 7 bd shows the technical grade fludioxonil, commercial fludioxonil suspension, and fludioxonil@MIL-101(Cu) II Fe III The inhibition zones of the chitosan oligosaccharide nanopesticides at corresponding concentrations all showed significant inhibition zones. The inhibition zones increased significantly with increasing concentration and also with increasing incubation time. Compared to the technical grade fludioxonil and commercial fludioxonil suspension, fludioxonil@MIL-101(Cu II Fe III @Chitosan oligosaccharide nanopesticides exhibited a significantly increased inhibition zone at the same concentration; moreover, within the same incubation period, the inhibition zone also significantly increased, and the corresponding EC... 50 The value was significantly reduced. The results indicate that the prepared fludioxonil@MIL-101(Cu) value was significantly reduced. II Fe III The antibacterial effect of chitosan oligosaccharide nanopesticides is significantly better than that of the technical grade fludioxonil and commercial fludioxonil suspension.

[0060] Example 3: Test of control effect against Botrytis cinerea on tomato leaves Different concentrations of fludioxonil@MIL-101(Cu II Fe III The control effect of chitosan oligosaccharide (prepared in Example 1) dispersion (solvent being a mixed solution of ethanol and water with 0.1% Tween-80) on Botrytis cinerea on tomato leaves: Spraying tomato leaves with fludioxonil@MIL-101 (Cu) at concentrations of 0.05 and 0.10 mg / L... II Fe III @Chitosan oligosaccharide dispersion, followed by inoculation of Botrytis cinerea on the leaves, and recording the size of the colony zone after different incubation times. Corresponding to technical grade fludioxonil, commercial fludioxonil suspension and MIL-101 (Cu II Fe III Chitosan oligosaccharide nanoparticles were used as controls.

[0061] Figure 8 Displays MIL-101 (Cu) II Fe IIIWhen the concentration of chitosan oligosaccharide nanoparticles reached 72 h, different incubation periods showed that the control effect against Botrytis cinerea on tomato leaves was not significant at a low concentration of 0.05 mg / L, but the control effect was more significant at a high concentration of 0.10 mg / mL. The technical grade fludioxonil, commercial fludioxonil suspension, and fludioxonil@MIL-101(Cu) were also tested. II Fe III The control effects of chitosan oligosaccharide nanopesticides at different concentrations were all significant, with the control effect becoming more pronounced with increasing concentration. Compared to the technical grade fludioxonil and commercial fludioxonil suspension concentrate, fludioxonil@MIL-101(Cu II Fe III The chitosan oligosaccharide nanopesticide exhibited significantly increased control efficacy at the same concentration and within the same incubation period. These results indicate that the prepared fludioxonil@MIL-101(Cu) nanopesticide... II Fe III The chitosan oligosaccharide nanopesticide showed significantly better control of Botrytis cinerea on tomato leaves than the technical grade fludioxonil and commercial fludioxonil suspension.

[0062] Example 4: Study on bidirectional transport within tomato plants To verify the fludioxonil@MIL-101(Cu) prepared in Example 1 II Fe III Chitosan oligosaccharide nanopesticides can be bidirectionally transported within tomato plants. We prepared nanopesticides using fluorescein isothiocyanate (FITC) labeling (denoted as FITC@MIL-101(Cu)). II Fe III )@chitosan oligosaccharide), tomato plant roots are immersed in a certain concentration of FITC@MIL-101 (Cu II Fe III After incubation for 12 hours in chitosan oligosaccharide nanoparticles, root, stem, and leaf tissues were collected, and fluorescence imaging was observed using a laser confocal microscope to indirectly verify the efficacy of fludioxonil@MIL-101(Cu) nanoparticles. II Fe III The chitosan oligosaccharide nanopesticide can be absorbed through the roots of tomato plants and transferred to the stems and leaves; similarly, the leaves of tomato plants immersed in a certain concentration of FITC@MIL-101 (Cu) II ,Fe III After incubation for 12 hours in chitosan oligosaccharide nanoparticles, root, stem, and leaf tissues were collected, and fluorescence imaging was observed using a laser confocal microscope to indirectly verify the efficacy of fludioxonil@MIL-101(Cu) nanoparticles. II Fe IIIChitosan oligosaccharide nanopesticides can be absorbed through the stomata on the leaves of tomato plants and transferred to the stems and roots of the tomato plants.

[0063] Figure 9 Displays FITC@MIL-101(Cu) II Fe III Chitosan oligosaccharide nanoparticles are absorbed through the stomata on the leaves of tomato plants and transferred to the stems and roots. They can also be absorbed through the root hairs of tomato plants and then transferred to the stems and leaves. These results indicate that fludioxonil@MIL-101(Cu) II Fe III Chitosan oligosaccharide nanopesticides can be delivered bidirectionally within tomato plants.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a nano-pesticide with bidirectional delivery function, characterized in that, The steps are as follows: (1) Organic ligands and mixed inorganic metal salts were subjected to a solvothermal reaction, followed by washing, reflux activation, and drying to obtain MIL-101 (Cu II Fe III MOF materials; (2) MIL-101 (Cu) in step (1) II Fe III MOF material and pesticide were mixed in a solvent, and then centrifuged and freeze-dried to obtain pesticide-loaded MIL-101 (Cu). II Fe III MOF; (3) The drug-loaded MIL-101 (Cu) from step (2) is loaded with the drug. II Fe III MOF was dispersed in water, then chitosan oligosaccharide was added, and the reaction was stirred at room temperature. After centrifugation, washing, and freeze-drying, pesticide @MIL-101(Cu) was obtained. II Fe III Chitosan oligosaccharide nanopesticides are nanopesticides with bidirectional delivery function.

2. The method for preparing nanopesticides with bidirectional delivery function according to claim 1, characterized in that: In step (1), the organic ligand is 2-amino-1,4-terephthalic acid or 1,4-terephthalic acid; the mixed inorganic metal salt includes iron salt and copper salt; the molar ratio of organic ligand, iron salt and copper salt is 9:6:

4.

3. The method for preparing nanopesticides with bidirectional delivery function according to claim 2, characterized in that: The solvothermal reaction is carried out at a temperature of 90-100℃ for a time of 12-24 h.

4. The method for preparing nanopesticides with bidirectional delivery function according to claim 1, characterized in that: In step (2), the size of the pesticide molecule is smaller than that of MIL-101 (Cu II Fe III The diameter of the pores in MOF materials; MIL-101 (Cu II Fe III The mass ratio of MOF material to pesticide is 1:2-1:

5.

5. The method for preparing nanopesticides with bidirectional delivery function according to claim 4, characterized in that: In step (3), the drug-loaded MIL-101 (Cu) is loaded. II Fe III The concentration of MOF was 1 mg / mL; the concentration of chitosan oligosaccharide was 1-3 mg / mL.

6. The method for preparing nanopesticides with bidirectional delivery function according to any one of claims 1-5, characterized in that: The pesticide in question is fludioxonil.

7. The nanopesticide with bidirectional delivery function prepared by the method of claim 6, characterized in that: The nanopesticide is MIL-101(Cu) with a diameter of less than 800 nm. II Fe III MOF nanoparticles.

8. The application of the nano-pesticide according to claim 7 in the preparation of an agent for controlling Botrytis cinerea on tomato leaves.

9. The application of the nano-pesticide according to claim 7 in the preparation of an agent that promotes bidirectional delivery of pesticides within tomato plants.

10. The application according to claim 9, characterized in that, The bidirectional transmission refers to: ① Nanopesticides are absorbed through the stomata on the leaves of tomato plants and then transferred to the stems and roots; ② Nanopesticides are absorbed by the root hairs of tomato plants and then transferred to the stems and leaves.

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