Preparation method and application of block polymer-metal organic framework coupled nano pesticide controlled release agent
Through the preparation of block polymer-metal organic framework coupling nanopestic chemical controlled release agent, the poor dispersion and resistance of traditional pesticides are solved, efficient and accurate pesticide release is achieved, and the agricultural pest control effect is significantly improved, and the agricultural pest control effect is promoted. Green agriculture development.
Patent Information
- Application Number
- CN202411385148.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2024-12-27
AI Technical Summary
Traditional pesticides have poor dispersion, resistance problems, environmental pollution and potential harm to non-target organisms, and it is difficult to achieve accurate release and efficient utilization of pesticides.
The block polymer-metal organic framework-coupled nanopesticide controlled release agent is prepared by solvent evaporation method and one-pot method, and is coated with ZIF-8 material to achieve high load and pH response controlled release of pesticides.
It significantly improves the load capacity and release efficiency of pesticides, achieves efficient prevention and control of agricultural pests, reduces the use of pesticides, reduces the harm to the environment and beneficial organisms, and promotes the development of green agriculture.
Smart Images
Figure CN119184078A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of pesticide preparation research and development, and in particular to the preparation of block polymer-metal organic framework coupled nano pesticide controlled-release agent and its application in agricultural pest control. Background Art
[0002] Pesticides are widely used to control pests and diseases. According to the Food and Agriculture Organization of the United Nations (FAO), the application of pesticides can increase the global agricultural production by 30%. However, traditional pesticides have disadvantages such as poor dispersibility, large amount of organic solvents, and long residence time in the soil. At the same time, the large-scale use of pesticides has caused resistance in pathogens and pests, accumulation in the food chain, soil degradation, eutrophication of water bodies, and other problems, which seriously threaten the environment and human health. Another major disadvantage of pesticides is that they are insoluble in water. At present, pesticides are mainly processed into suitable formulas through solvents, carriers, dispersants, emulsifiers or other auxiliary materials for field use. In this regard, nanotechnology has been considered as a favorable tool, providing new solutions for the preparation and delivery of active ingredients of pesticides. The carrier materials currently reported for nanopesticides are mainly metal and non-metal oxides, carbon-based materials, quantum dots, polymers, lipids and metal organic frameworks (MOFs).
[0003] In recent years, MOFs have shown great development potential in efficient and safe pesticides due to their high structural stability, strong drug loading capacity, and good biocompatibility. They are innovative and promising new materials in the agricultural industry. However, MOFs are still in the early stages of agricultural pest control research. ZIF is a special subclass of MOF. The zeolitic imidazole framework ZIF-8 is composed of Zn 2+ and imidazole ligands, and is a member of the ZIF family with good biocompatibility, high loading efficiency, good controlled release ability, and large surface area. Therefore, ZIF-8 is considered to be a promising drug delivery carrier. ZIF-8 nanoparticles are easily decomposed under acidic conditions and are therefore suitable for constructing pH-responsive delivery systems. However, previous studies have shown that ZIF-8 has low drug loading efficiency, and some MOF-based nanopesticides are prepared by encapsulating pesticides in nanomaterials without external coatings, resulting in the premature release of large amounts of pesticides. Therefore, the preparation of nanopesticides with double-layer carrier coating and stimulus-responsive release is an effective way to improve the utilization rate of pesticides and achieve precise release of pesticides.
[0004] Amphiphilic lipid polymers are typical nanocarriers and are widely used in drug delivery. The PEG chain forms a hydrophilic shell and a hydration film on the surface of the liposome, which makes the nanoparticles have good solubility. The DSPE part can form the core of the nanoparticles, thereby providing drug-carrying space. After encapsulation by amphiphilic lipid polymers, the stability of pesticides can be improved and photodegradation can be reduced. In addition, liposomes have good biocompatibility and biodegradability, so they have broad application prospects in agriculture.
[0005] Widely used nicotinoid insecticides such as imidacloprid, thiamethoxam, and dinotefuran are characterized by broad spectrum, high efficiency, low toxicity, and low residue. It has a highly effective control effect on a variety of piercing-sucking mouthparts pests. However, nicotinoid insecticides have potential risks of varying degrees of harm to non-target insects and other beneficial organisms, especially aquatic organisms. It is worth noting that nicotinoid pesticides are also significantly toxic to pollinating insect populations such as bees. Therefore, improving the utilization rate of nicotinoid pesticides such as imidacloprid to improve the control effect on target pests and reduce toxicity to beneficial organisms is of great significance for protecting ecosystem biodiversity and ecological environment. Emamectin benzoate is a broad-spectrum and highly effective semi-synthetic antibiotic pesticide. However, traditional emamectin benzoate preparations have problems such as poor water solubility, short duration, and low utilization rate, and also pose a potential threat to environmental safety and human health. By constructing new preparations with controllable and precise release performance, it is of great significance for the safe use of pesticides and promoting the green and high-quality development of agriculture. Summary of the invention
[0006] The present invention aims to overcome the shortcomings of the prior art and provide a method for preparing a pH-responsive block polymer-metal organic framework coupled nanopesticide controlled-release agent and its application. The nanopesticide controlled-release agent has a high drug loading capacity and can promote the effect of reducing pesticide use and increasing efficiency and the development of green agriculture. It has significant economic, social and ecological benefits and has broad application prospects in the field of green control technology for agricultural pests.
[0007] To achieve the above-mentioned purpose, the present invention provides a block polymer-metal organic framework coupled nano pesticide controlled-release agent, comprising a block polymer, a pesticide and a MOFs material.
[0008] Preferably, the pesticide is one or two of nicotinoid insecticides such as imidacloprid, thiamethoxam, or dinotefuran, and avermectin benzoate.
[0009] Preferably, the block polymer is DSPE-PEG 2000 -NH2 or DSPE-SS-PEG 2000 -NH2.
[0010] Preferably, the MOFs material is ZIF-8, which is prepared by a one-pot process using 2-methylimidazole as a ligand and zinc nitrate hexahydrate as a zinc salt, which is first coordinated with the amino group on the block polymer and then used as a coordinating ion.
[0011] Preferably, the drug loading of the block polymer-metal organic framework coupled nano pesticide controlled-release agent is 70%-80%.
[0012] Preferably, the particle size of the block polymer-metal organic framework coupled nano pesticide controlled-release agent is 200-300 nm.
[0013] A method for preparing a block polymer-metal organic framework coupled nano pesticide controlled release agent, the method for preparing the above-mentioned nano pesticide controlled release agent is as follows: an amphiphilic block polymer and a pesticide are mixed in a certain proportion in the presence of a small amount of organic solvent, and the polymer nanoparticles are rapidly stirred at room temperature by a solvent evaporation method; MOFs material is further coated on the polymer nanoparticles by a one-pot method, and the specific steps are: firstly a certain amount of zinc nitrate hexahydrate is added to the polymer nanoparticles and stirred to react at room temperature for 4 hours, then 2-methylimidazole is added, and the reaction is carried out at room temperature for 1 hour. After the reaction is completed, the mixture is centrifuged and washed with ethanol three times, and freeze-dried to obtain the block polymer-metal organic framework coupled nano pesticide controlled release agent.
[0014] Furthermore, the presence of a small amount of organic solvent means that the mass fraction of the organic solvent is 1% to 3%, and the organic solvent is tetrahydrofuran or chloroform.
[0015] Furthermore, the reaction conditions of the solvent evaporation method are: stirring at room temperature for 48 h, followed by filtration with a 0.22 µm polyethersulfone filter membrane.
[0016] Furthermore, the application of the block polymer-metal organic framework coupled nano pesticide controlled release agent is as follows: the block polymer-metal organic framework coupled nano pesticide controlled release agent is formulated into a certain concentration and sprayed on crops; the block polymer-metal organic framework coupled nano pesticide controlled release agent has pH and redox responsive controlled release properties.
[0017] Furthermore, the pesticide includes any one or two of imidacloprid, thiamethoxam, dinotefuran and avermectin benzoate.
[0018] Furthermore, the nano pesticide controlled-release agent is used in the prevention and control of fall armyworm, aphids, and piercing-sucking and rasp-sucking agricultural pests.
[0019] Beneficial effects of the present invention: (1) The nanopesticide controlled-release agent comprises a block polymer-metal organic framework coupled nanocarrier, one or two of a nicotinoid pesticide such as imidacloprid, thiamethoxam, or dinotefuran, and avermectin benzoate; the nanocarrier is an amphiphilic block polymer DSPE-PEG 2000 -NH2 or DSPE-SS-PEG 2000 -NH2 and MOFs materials were used to prepare block polymer-metal organic framework coupled nano pesticide controlled release agents by solvent evaporation method and one-pot method. Block polymer-metal organic framework coupled nanocarriers can achieve dual loading of pesticides, significantly increase the loading amount of pesticide active ingredients, and have the characteristics of controlled, precise and sustained release. Compared with traditional pesticide formulations, the block polymer-metal organic framework coupled nano pesticide controlled release agent can effectively kill agricultural lepidoptera and stinging (file) sucking pests such as fall armyworm and aphids, has a significant effect of reducing dosage and increasing efficiency, and has significant economic, social and ecological benefits. It has broad application prospects in the field of agricultural pest control and promoting the development of green agriculture.
[0020] (2) The block polymer-metal organic framework coupled nano pesticide controlled release agent proposed in the present invention has nanoscale size and high drug loading, and has pH response characteristics, which can achieve precise and controlled release of drugs. Indoor biological activity assays show that it has good control effect on agricultural pests and the control effect lasts for a long time. Compared with traditional pesticide formulations, it has a significant effect of reducing dosage and increasing efficiency. It provides a scientific basis for reducing pesticide dosage and increasing efficiency and green and sustainable prevention and control of plant diseases and insect pests. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is a scanning electron microscope image of a block polymer-metal organic framework coupled nano pesticide controlled release agent in a preferred embodiment of the present invention; Figure 2 The X-ray diffraction diagram of the block polymer-metal organic framework coupled nano pesticide controlled release agent in the preferred embodiment of the present invention; Figure 3 The ultraviolet absorption spectrum of the block polymer-metal organic framework coupled nano pesticide controlled release agent in the preferred embodiment of the present invention; Figure 4 This is a graph showing the control effect of the block polymer-metal organic framework coupled nano pesticide controlled release agent on the second instar larvae of the fall armyworm in a preferred embodiment of the present invention; Figure 5 This is a diagram showing the control effect of the block polymer-metal organic framework coupled nano pesticide controlled-release agent on aphids in a preferred embodiment of the present invention. DETAILED DESCRIPTION
[0022] The technical solutions in the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.
[0023] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.
[0024] The present invention does not disclose the raw materials for preparing imidacloprid (IMI), distearoyl phosphatidylethanolamine PEG amine (DSPE-PEG 2000 The sources of phospholipid-disulfide bond-polyethylene glycol-amino group, 2-methylimidazole, zinc nitrate hexahydrate, anhydrous ethanol, tetrahydrofuran, etc. are specifically limited, and conventional commercial raw material products in the field are applicable.
[0025] 1. Preparation of block polymer-metal organic framework coupled nanopesticide controlled release agent Example 1 2 mg of the amphiphilic block polymer DSPE-PEG 2000 -NH2 and 50 mg of imidacloprid were added to 2 mL of tetrahydrofuran and fully dissolved by ultrasound. 18 mL of ultrapure water was dripped into the above solution dropwise under ultrasound conditions, and then the organic solvent was removed by rapid stirring at room temperature for 48 hours, followed by filtration with a 0.22 µm polyethersulfone filter membrane to obtain polymer nanoparticles.
[0026] 0.15 g of zinc nitrate hexahydrate was added to the polymer nanoparticle solution and reacted at room temperature for 4 hours. Then 0.16 g of 2-methylimidazole was added and the reaction was continued for 1 hour. The solution was centrifuged at 10,000 rpm for 2 min, the supernatant was discarded, and the precipitate was collected and freeze-dried to obtain the block polymer-metal organic framework coupled nanopesticide controlled release agent IMI-DSPE@ZIF-8 (drug loading of 70%~80%).
[0027] The scanning electron microscopy results of the prepared block polymer-metal organic framework coupled nanopesticide controlled release agent are as follows: Figure 1 As shown in a: The block polymer-metal organic framework coupled nano pesticide controlled release agent prepared by the method of the present invention is in a polyhedral shape with a size of about 200-300 nm. Figure 2 As shown in the figure, the X-ray diffraction peak of the block polymer-metal organic framework coupled nano pesticide controlled release agent is consistent with that of ZIF-8, indicating that imidacloprid is successfully encapsulated into the block polymer-metal organic framework coupled material. Figure 3As shown in the figure, under acidic conditions, the absorption peak of imidacloprid at 259 nm of the block polymer-metal organic framework coupled nanopesticide controlled release agent is significantly enhanced. This is because under acidic conditions, ZIF-8 disintegrates, releasing imidacloprid accumulated in the polymer nanoparticles. It also shows that the block polymer-metal organic framework coupled nanopesticide controlled release agent has pH-responsive release performance when the pH is less than 6.0.
[0028] Example 2 2 mg of the amphiphilic block polymer DSPE-SS-PEG 2000 -NH2 and 50 mg of avermectin benzoate were added to 2 mL of tetrahydrofuran and fully dissolved by ultrasound. 18 mL of ultrapure water was dripped into the above solution drop by drop under ultrasound, and then the organic solvent was removed by rapid stirring at room temperature for 48 hours, followed by filtration with a 0.22 µm polyethersulfone filter membrane to obtain polymer nanoparticles.
[0029] 0.15 g of zinc nitrate hexahydrate was added to the polymer nanoparticle solution and reacted at room temperature for 4 hours. Then 0.16 g of 2-methylimidazole was added and the reaction was continued for 1 hour. The solution was centrifuged at 10,000 rpm for 2 min, the supernatant was discarded, and the precipitate was collected and freeze-dried to obtain the block polymer-metal organic framework coupled nanopesticide controlled release agent EB-DSPE@ZIF-8 (drug loading 70%~80%).
[0030] The scanning electron microscopy results of the prepared block polymer-metal organic framework coupled nanopesticide controlled release agent are as follows: Figure 1 As shown in b: the block polymer-metal organic framework coupled nano pesticide controlled release agent prepared by the method of the present invention has a size of about 200-300 nm.
[0031] The experimental results show that both Example 1 and Example 2 obtain block polymer-metal organic framework coupled nano pesticide controlled-release agents with good dispersibility and nanoscale size, and therefore they are further used in production for the prevention and control of agricultural pests.
[0032] (II) Application of block polymer-metal organic framework coupled nanopesticide controlled release agents in agricultural pest control Application Example 1 Indoor toxicity of block polymer-metal organic framework coupled nanopesticide controlled release agent against the second instar larvae of Spodoptera frugiperda The leaf dipping method was used for indoor toxicity determination. The block polymer-metal organic framework coupled nano pesticide controlled release agent prepared in Example 2 of (I) was set to 5 series of mass gradient concentrations of 0.025, 0.05, 0.075, 0.1, and 0.2 mg / L in equal proportions. Clean and uncontaminated fresh corn leaves were cut and immersed in the pre-prepared solution for 10 s. The leaves were taken out and dried naturally, and then moved into a bioassay box with a moist filter paper on the bottom. Ten second-instar larvae of the fall armyworm hatched on the same day were inoculated into each treatment. Clean water treatment was set as a blank control. Each treatment was repeated 3 times. The mortality of the test insects in each treatment was checked after 24 hours of treatment. The test set avermectin benzoate microemulsion as a reference to evaluate the insecticidal activity of the block polymer-metal organic framework coupled nano pesticide controlled release agent and the traditional formulation.
[0033] The test results show that ( Figure 4 As shown): The insecticidal activity of the block polymer-metal organic framework coupled nanopesticide controlled-release agent against the fall armyworm is significantly higher than that of the 5.7% emamectin benzoate microemulsion under the same concentration conditions, especially the synergistic effect is more significant under the low concentration conditions of 0.025mg / L-0.05mg / L. This is because the EB stability and sustained-release performance are significantly improved after encapsulation by the block polymer-metal organic framework coupled nanomaterials, which plays an important role in improving the rapid and persistent control effects of emamectin benzoate against agricultural pests, and can achieve the purpose of reducing the amount and frequency of use in the field, which is of great significance for achieving the reduction and efficiency of pesticides and promoting the green and high-quality development of agriculture.
[0034] Application Example 2 Determination of the control effect of block polymer-metal organic framework coupled nanopesticide controlled release agent on pea aphids The control effect of the block polymer-metal organic framework coupled nano pesticide controlled release agent prepared in Example 1 in (I) on pea aphids was determined by the stem and leaf spray method. The dosage of the block polymer-metal organic framework coupled nano pesticide controlled release agent was set to 1.5 g / mu with reference to the dosage of the imidacloprid water dispersible granules that have been registered as pesticides by the Ministry of Agriculture and Rural Affairs of China. The pea seedlings were cultured in a growth room (25°C, 16 h / 8 h day / night, 75% humidity) until the seedlings grew to have more than 7 leaves. Then, the same concentration of 70% imidacloprid water dispersible granules and block polymer-metal organic framework coupled nano pesticide controlled release agent were sprayed on the pea seedlings. Leaves were collected for aphids to feed on the 1st, 4th and 7th days after application. 30 nymphs were treated each time, with 3 replicates, and clear water was used as a blank control. The corrected mortality rate was calculated after 24 hours. The difference in the control effect of block polymer-metal organic framework coupled nano pesticide controlled release agent and 70% imidacloprid water dispersible granules on pea aphids was determined and compared.
[0035] The lethal effects on pea aphids at different times after application are as follows: Figure 5 As shown in the figure, the block polymer-metal organic framework coupled nano pesticide controlled release agent has a good control effect on pea aphids. Under the same dosage conditions, the control effect of the block polymer-metal organic framework coupled nano pesticide controlled release agent is significantly better than the control effect of the 70% imidacloprid water dispersible granules registered by the Ministry of Agriculture and Rural Affairs of my country. This is because nano-sizing can prevent the rapid degradation of the active ingredients under environmental conditions, thereby improving the long-term control effect on pests. In addition, the block polymer-metal organic framework coupled nano pesticide controlled release agent has the ability of slow release and controlled release, and can be intelligently released according to the microecological environment of the digestive system of pea aphids. Compared with imidacloprid water-dispersible granules, under the same active ingredient dosage conditions, the block polymer-metal organic framework coupled nano pesticide controlled-release agent has a higher preventive effect on aphids, and its toxic effect 7 days after application is still significantly better than that of imidacloprid water-dispersible granules, indicating that the nano pesticide controlled-release agent of the present invention has a longer lasting effect and achieves a longer-term continuous control effect of pesticides on pests, which helps to improve the utilization rate of imidacloprid in the environment, can reduce the amount of imidacloprid used in the field, achieve the purpose of reducing the use of pesticides and increasing their efficiency, and further promote the green and high-quality development of agriculture.
[0036] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the invention are within the scope of protection of the present invention.
Claims
1. A block polymer-metal organic framework coupled nano pesticide controlled release agent, characterized in that: It includes amphiphilic block polymer, imidacloprid or thiamethoxam or dinotefuran or avermectin benzoate, and MOFs material, and the mass ratio thereof is 1:1~25:1~8.
2. The block polymer-metal organic framework coupled nano pesticide controlled release agent according to claim 1, characterized in that: The MOFs material is ZIF-8.
3. The block polymer-metal organic framework coupled nano pesticide controlled release agent according to claim 1, characterized in that: The amphiphilic block polymer is DSPE-PEG 2000 -NH2 or DSPE-SS-PEG 2000 -NH2.
4. The method for preparing the block polymer-metal organic framework coupled nano pesticide controlled release agent according to claim 1, characterized in that: The method comprises the following steps: in the presence of a small amount of organic solvent, an amphiphilic block polymer, imidacloprid or thiamethoxam or dinotefuran or avermectin benzoate are added in a mass ratio of 1:1-25, and the mixture is rapidly stirred and filtered at room temperature to obtain polymer nanoparticles by a solvent evaporation method; then, a MOFs material is coated on the polymer nanoparticles by a one-pot method, that is, zinc nitrate hexahydrate is firstly added, stirred and reacted at room temperature for 4 hours, and then 2-methylimidazole is added, and the mixture is reacted at room temperature for 1 hour. After the reaction is completed, the mixture is centrifuged and washed with ethanol three times, and freeze-dried to obtain a block polymer-metal organic framework coupled nano pesticide controlled release agent.
5. The preparation method according to claim 4, characterized in that: The organic solvent is tetrahydrofuran or chloroform.
6. The preparation method according to claim 4, characterized in that: The reaction conditions of the solvent evaporation method are: stirring the reaction at room temperature for 48 hours, and then filtering with a 0.22 µm filter membrane.
7. The use of the block polymer-metal organic framework coupled nano pesticide controlled release agent according to claim 1, characterized in that: The block polymer-metal organic framework coupled nano pesticide controlled release agent is prepared into a certain concentration and sprayed on crops; the block polymer-metal organic framework coupled nano pesticide controlled release agent has pH and redox responsive controlled release performance.
8. The use according to claim 7, characterized in that: The pesticide comprises any one or two of imidacloprid, thiamethoxam, dinotefuran and avermectin benzoate.
9. The use according to claim 8, characterized in that: The nano pesticide controlled-release agent is applied to the prevention and control of lepidoptera and piercing-sucking and rasp-sucking agricultural pests.