High-entropy nano-carrier controlled-release pesticide, preparation method and application thereof

Abstract

The application discloses a high-entropy nano-carrier controlled-release pesticide, a preparation method and application thereof, and belongs to the technical field of loaded pesticides.The application aims to solve the technical problems of limited action sites, insufficient loading stability, difficult release behavior control, single function, lack of nutrition supplement and synergistic bactericidal function of existing pesticide carriers.The controlled-release pesticide comprises a five-element high-entropy oxide nanofiber carrier composed of Zn, Co, Fe, Cu and Gd and at least one pesticide loaded on the carrier, which is obtained through electrospinning.The application selects metal ions based on specific uses, finally constructs a high-entropy oxide nanofiber based on five-element metal cations, and then constructs a controlled-release pesticide system integrating drug loading, release control, light-heat synergistic effect, two-phase conduction, bacteriostasis and crop growth regulation.The controlled-release pesticide can be applied to the field of crops.

Description

Technical Field

[0001] This invention belongs to the field of supported pesticide technology, specifically relating to a high-entropy nanocarrier controlled-release pesticide, its preparation method, and its application. Background Technology

[0002] Traditional pesticides play a vital role in the control of agricultural pests and diseases, but their practical application still suffers from problems such as poor photostability, easy runoff, and difficulty in controlling release behavior. After application, pesticides often release rapidly in the initial stages, easily leading to burst release. Furthermore, they lack the ability to respond to changes in light, temperature, or the disease environment, making it difficult to achieve continuous, on-demand release. Therefore, the effective utilization rate of traditional pesticides is usually low, requiring not only increased application rates or repeated applications but also potentially causing pesticide residues and environmental pollution. Thus, using suitable carriers to load and disperse the active ingredients of pesticides is an important technical means to improve the performance of pesticide formulations.

[0003] Existing pesticide carriers mainly include polymers, porous materials, and single or few-component inorganic materials. While these carriers can improve pesticide stability or responsive release performance to some extent, their composition and function are generally limited, with a limited number of surface interaction sites. They lack the ability to stably load and regulate pesticide release, making it difficult to simultaneously achieve sustained release and environmentally responsive release. Some carriers also lack UV protection for pesticides, making it difficult to inhibit pesticide decomposition under light conditions, and they are prone to migration and runoff in the soil. Furthermore, some carriers only function as load carriers, lacking a single function and failing to meet the development needs for multifunctional pesticide carriers. Summary of the Invention

[0004] The purpose of this invention is to address the technical problems of existing pesticide carriers, such as limited sites of action, insufficient loading stability, difficulty in controlling release behavior, and limited functionality, lack of nutritional supplementation and synergistic bactericidal effects. This invention provides a high-entropy nanocarrier controlled-release pesticide, its preparation method, and its applications. A multifunctional agricultural carrier system integrating stable drug loading, pH-responsive release, photoresponsive release, photothermal synergistic bactericidal effect, UV protection, anti-leakage, bidirectional conduction, synergistic antibacterial effect, and nutritional supplementation is constructed.

[0005] The technical solution of the present invention is as follows: One objective of this invention is to provide a high-entropy nanocarrier controlled-release pesticide, wherein the controlled-release pesticide comprises a pentagonal high-entropy oxide nanofiber carrier composed of Zn, Co, Fe, Cu and Gd obtained by electrospinning and at least one pesticide loaded on the carrier.

[0006] Further specified, the pesticides include difenoconazole, tebuconazole, hexaconazole, azoxystrobin, pyraclostrobin, and carbendazim, with a pesticide loading of 25-30 wt%.

[0007] Further specifying, the molar ratio of Zn, Co, Fe, Cu and Gd in the nanofiber carrier is 1:1:1:1:1.

[0008] The second objective of this invention is to provide a method for preparing a high-entropy nanocarrier controlled-release pesticide, the method comprising the following steps: Step 1: Dissolve the metal salts of zinc, cobalt, iron, copper and gadolinium in N,N-dimethylformamide (DMF) in equimolar ratio, then add polyvinylpyrrolidone (PVP), mix and stir to obtain a homogeneous and stable precursor solution; Step 2: Electrospin the precursor solution under a high voltage electrostatic field to obtain continuous precursor nanofibers; Step 3: Place the precursor nanofibers in a tube furnace and calcine them in an air atmosphere to obtain Zn-Co-Fe-Cu-Gd high-entropy oxide nanofibers with a porous structure. Step 4: Mix the obtained nanofibers with pesticides under stirring to obtain high-entropy nanocarrier controlled-release pesticides.

[0009] Further specifying, the concentration of polyvinylpyrrolidone (PVP) in the precursor solution in step 1 is 0.1-0.2 g / mL.

[0010] Further specifying, the concentration of zinc metal salt in the precursor solution in step 1 is 0.004-0.006 g / mL.

[0011] Further specifying the electrospinning parameters in step 2: the distance between the nozzle and the receiver is 10-15cm, the voltage is 16-19kV, and the feed rate is 1-1.5mL / h.

[0012] Further specifying, the calcination temperature in step 3 is 350-450℃, and the holding time is 1.5-2.5h.

[0013] Further specifying, in step 4, the mass ratio of nanofibers to pesticides is 1:(14-16).

[0014] The third objective of this invention is to provide an application of high-entropy nanocarrier controlled-release pesticides in the field of crops.

[0015] To further specify, agricultural crops include soybeans.

[0016] The advantages of this invention compared to existing technologies are: This invention innovatively proposes using high-entropy oxide nanofibers as pesticide carriers. Based on specific applications, metal ions are screened to ultimately construct a high-entropy oxide nanofiber system based on pentagonal metal cations, characterized by multi-element synergy, lattice distortion, abundant surface active sites, and tunable composition. Subsequently, a controlled-release pesticide system integrating drug loading, controlled release, photothermal synergy, biphasic conduction, antibacterial activity, and crop growth regulation is constructed. Specific advantages are as follows: (1) This invention uses five metal elements, Zn, Co, Fe, Cu and Gd, to construct a high-entropy oxide, so that multiple metal cations coexist in the oxide lattice, forming a high-entropy structure with characteristics such as multi-element synergy, lattice distortion, abundant interaction sites and tunable composition. This invention is not a simple physical mixture of five single metal oxides, but a synergistic system selected based on the screening of metal ions for specific applications. The fiber composition is uniform, the morphology is complete and the structure is stable.

[0017] (2) This invention utilizes the abundant metal interaction sites on the surface of high-entropy oxides to coordinate with pesticide molecules for loading, especially utilizing the interaction between metal sites such as Gd and the coordinating groups in pesticide molecules to improve the binding stability between pesticides and carriers. This loading method differs from simple adsorption, embedding, or physical mixing, and can reduce the rapid desorption of pesticides and burst release at the initial stage of application, achieving stable pesticide loading. In addition, the high-entropy oxide nanofibers of this invention have continuous fiber morphology and porous structure, which further increases the contact and interaction between pesticide molecules and carriers, further improving the stability of pesticide loading and providing a structural basis for the regulation of pesticide release behavior, thus achieving a sustained-release effect.

[0018] (3) This invention utilizes the composition and surface properties of high-entropy oxides to enable the drug-loaded system to generate a pH response to the acidic microenvironment associated with disease, promoting pesticide release under acidic conditions and thus improving the drug release efficiency at diseased sites. Simultaneously, the high-entropy oxide nanofibers can absorb light energy and convert it into heat energy, promoting pesticide release through the photothermal effect and achieving responsive release under light conditions. Therefore, this invention is a dual-response controlled-release system combining responsive release in the acidic microenvironment of disease and photothermal responsive release, achieved through high-entropy oxide nanofibers, to reduce pesticide burst release and achieve continuous, controllable, and on-demand release.

[0019] (4) The high-entropy oxide nanofibers of the present invention possess photothermal conversion properties, which can convert absorbed light energy into heat energy under illumination, inhibiting the growth of pathogens through local thermal effects and serving as the basis for light-responsive release performance. In addition, metal components such as Cu and Zn can exert antibacterial effects and form a synergistic effect with the loaded pesticides and photothermal effects. Therefore, the present invention forms a multi-synergistic bactericidal mechanism that combines pesticide bactericidal, metal element bacteriostatic, and photothermal bactericidal effects.

[0020] (5) This invention utilizes high-entropy oxide nanofibers to protect pesticides, reducing pesticide decomposition caused by ultraviolet light irradiation and improving the photostability and field retention of pesticides. At the same time, the migration ability of pesticides in the soil is reduced after loading, making them less prone to rapid migration and loss with water, which is beneficial to improving the retention of pesticides in the application area and reducing environmental losses.

[0021] (6) The present invention utilizes the nanoscale characteristics of high-entropy oxide nanofibers to provide conditions for the migration and transfer of the carrier and its loaded components in crop tissues, enabling it to be bidirectionally conducted upward and downward in the plant, thereby expanding the range of action of pesticides in the plant.

[0022] (7) Under suitable application conditions, the metal elements such as Zn, Fe and Co in this invention can provide crops with certain trace element supplementation, which is beneficial to improving crop growth. Therefore, high-entropy oxide nanofibers no longer only undertake the function of pesticide loading, but combine pesticide delivery with trace element supplementation, so that the carrier has the functions of disease prevention and control and crop growth promotion. Attached Figure Description

[0023] Figure 1 The image shows a scanning electron microscope image of the precursor nanofibers obtained in step 2 of Example 1. Figure 2 The macroscopic morphology and scanning electron microscope image of the high-entropy oxide nanofibers obtained in step 3 of Example 1 are shown. Figure 3 The X-ray diffraction patterns of HEO, DIF, and DIF@HEO in Example 1 are shown. Figure 4 Fourier transform infrared spectra of HEO, DIF, and DIF@HEO in Example 1; Figure 5 XPS analysis spectra of HEO and DIF@HEO in Example 1; (a) is HEO, (b) is DIF@HEO; Figure 6 The XPS analysis spectra of DIF and DIF@HEO in Example 1 are O 1s; (a) is DIF, (b) is DIF@HEO; Figure 7 N 1s of the XPS analysis spectra of DIF and DIF@HEO in Example 1; (a) is DIF, (b) is DIF@HEO; Figure 8 The curves showing the residual rate changes of DIF and DIF@HEO under ultraviolet light irradiation conditions in Example 1 are shown. Figure 9 The effect of DIF@HEO on soybean seed germination in Example 1; Figure 10 The effect of DIF@HEO on seedling growth in Example 1; Figure 11 for Figure 10 Comparison of seedling fresh weight before and after treatment; Figure 12 for Figure 10 Comparison of seedling root length before and after treatment; Figure 13 for Figure 10 Comparison of seedling height before and after treatment; Figure 14 The cumulative release curves of DIF@HEO in Example 1 under different pH conditions and near-infrared light irradiation are shown. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0026] Example 1: The preparation method of the high-entropy nanocarrier controlled-release pesticide in this example is carried out according to the following steps: Step 1: Weigh 0.5 mmol of zinc, cobalt, iron, copper and gadolinium nitrates in an equimolar ratio (Zn:Gd:Fe:Cu:Co = 1:1:1:1:1) and dissolve them in 30 mL of N,N-dimethylformamide (DMF). Then add 4.5 g of polyvinylpyrrolidone (PVP) and mix and stir for 7 h to obtain a homogeneous and stable precursor solution. Step 2: The precursor solution was electrospun under a high-voltage electrostatic field. The spinning parameters were: nozzle-receiver distance 15 cm, voltage 19 kV, and feed rate 1.5 mL / h. Continuous precursor nanofibers were obtained; their scanning electron microscope images are shown below. Figure 1 As shown, the obtained nanofibers exhibit a continuous, smooth morphology without bead-like defects, with relatively uniform fiber diameter and a uniform overall structure. Step 3: The precursor nanofibers were placed in a tube furnace and calcined in air at 400℃ for 2 hours to decompose and remove the PVP component and promote the crystallization of the metal oxide, thereby obtaining Zn-Co-Fe-Cu-Gd high-entropy oxide nanofibers (HEO) with a porous structure; its macroscopic morphology and scanning electron microscope images are shown below. Figure 2As shown, the calcined sample is brownish-brown, and the surface of the high-entropy oxide nanofibers is relatively rough with obvious pores. No large-area melting or severe agglomeration was observed, indicating that the high-entropy oxide nanofiber porous structure was successfully formed after heat treatment. Step 4: The obtained nanofibers (HEO) and difenoconazole (DIF) were mixed at a mass ratio of 1:15. After mechanical stirring for 24 h, the mixture was centrifuged and dried. The coordination between the metal active sites and the pesticide molecules stabilized the pesticide molecules on the surface and within the nanofiber structure, resulting in a high-entropy nanocarrier controlled-release pesticide (DIF@HEO). The amount of stably loaded DIF was determined to be 27.33 wt% by high-performance liquid chromatography.

[0027] Example of effect (a) X-ray diffraction test like Figure 3 In the XRD pattern shown, HEO only shows one set of main crystal phase diffraction peaks, and no obvious impurity phase peaks were observed. This indicates that multiple metal elements such as Zn, Co, Fe, Cu and Gd may enter the same crystal lattice together to form a single-phase solid solution structure, proving the formation of a high-entropy oxide.

[0028] (II) Fourier Transform Infrared Testing like Figure 4 In the Fourier transform infrared spectrum shown, DIF@HEO retains the characteristic absorption peaks of DIF and the relevant characteristic signals of HEO. Meanwhile, the X-ray diffraction peaks of DIF in DIF@HEO are significantly weakened, indicating that the crystallinity of DIF is reduced and it has been successfully loaded into HEO nanofibers in a relatively dispersed state.

[0029] (III) Pesticide Stabilization Mechanism Based on Metal Coordination To further verify the interaction mechanism between HEO and DIF, X-ray photoelectron spectroscopy (XPS) analysis was performed on HEO and DIF@HEO. Figure 5-7 As shown, the electron binding energy of Gd in HEO changes after DIF loading, indicating that the electronic environment around Gd is affected by the DIF molecule, suggesting that the Gd active site participates in the pesticide molecule binding process. Simultaneously, analysis of characteristic elements in DIF reveals that the N1s and O1s related peaks in DIF@HEO both shift to some extent, indicating electronic interactions between the nitrogen-containing and oxygen-containing groups in the difenoconazole molecule and the metal active sites in the high-entropy oxide. This demonstrates that high-entropy oxide nanofibers do not load pesticides through simple physical adsorption, but rather utilize the interaction between the metal active sites such as Gd and the coordinable groups in the DIF molecule to achieve stable binding of pesticide molecules and improve the stability of the pesticide loading system.

[0030] (iv) Resistance to UV degradation of high-entropy oxide nanofibers To evaluate the photostable protective effect of high-entropy oxide nanofibers against difenoconazole, the stability of DIF and DIF@HEO systems under ultraviolet light irradiation (3W, 254nm UV lamp) was tested. Figure 8 As shown, with increasing UV irradiation time, the pesticide content in both DIF and DIF@HEO gradually decreased, but the DIF@HEO system exhibited higher stability. After 32 h of UV irradiation, the DIF residue rate in DIF@HEO was significantly higher than that in DIF, indicating that high-entropy oxide nanofibers can effectively reduce pesticide degradation caused by UV radiation and improve the stability of difenoconazole in the environment.

[0031] (V) The crop growth-promoting properties of high-entropy oxide nanofibers To evaluate the effects of high-entropy oxide nanofiber carriers on crop growth, soybean seeds were used as the research subject for germination experiments. Plump soybean seeds were selected, washed, and then placed in 20 mL of aqueous dispersions of different concentrations (50, 100, and 200 mg / L) and soaked in a shaker at 28℃ for 12 h. Water (CK), difenoconazole (DIF ME), and pesticide-free high-entropy oxide nanofiber carriers (HEO) were used as controls. After soaking, the seeds were placed in moistened filter paper petri dishes, and germination was recorded. The results are as follows: Figure 9 As shown, compared with the CK group, the soybean seeds treated with HEO exhibited better germination rate and shoot length, which was 1.125 times that of the CK group. The DIF@HEO treatment group also showed better germination than the DIF treatment group.

[0032] To further observe seedling morphology, soybean seeds were disinfected with 0.2% potassium permanganate before sowing and cultivation. Once the first pair of true leaves had unfolded, seedlings with uniform growth were selected for treatment. Different concentrations of sample aqueous solutions (50, 100, 200 mg / L) were applied to the roots every 14 days, with water (CK), difenoconazole (DIF ME), and pesticide-free high-entropy oxide nanofiber carriers (HEO) serving as controls. Root length, plant height, and fresh weight of seedlings were measured 14 days after the second treatment. Figure 10-13 As shown, HEO treatment promoted the growth of soybean seedling roots and aboveground parts. At a concentration of 200 mg / L, plant height, root length, and fresh weight were 1.19, 1.11, and 1.06 times that of the CK group, respectively. The DIF@HEO group showed 1.34, 1.14, and 1.13 times that of the DIF group, respectively. This indicates that high-entropy oxide nanofibers, in addition to their pesticide loading function, can also play a role in supplementing plant micronutrients. This promoting effect is related to the release of elements such as Zn, Fe, and Co from HEO, which provides micronutrient supplementation, thereby improving plant growth.

[0033] (vi) Environmental response release properties of high-entropy oxide nanofibers Release performance tests were conducted on the DIF@HEO system at pH values ​​of 4.5, 6.0, 7.0, and 8.0. These values ​​corresponded to simulated acidic soil, the pH level most susceptible to soybean disease, neutral soil, and alkaline soil, respectively. Release levels were measured at each pH level, and the results are as follows: Figure 14 As shown, the DIF@HEO system exhibits a clear environmentally responsive release characteristic. The release behavior of DIF@HEO varies significantly under different pH conditions. In acidic environments, as the pH decreases, the interaction between the metal active sites on the carrier surface and pesticide molecules is regulated, promoting the release of DIF molecules from the high-entropy oxide nanofiber structure. This allows the pesticide-loaded system to respond to the acidic microenvironment formed in the crop diseased area, achieving preferential release from the diseased area. Under neutral and other environmental conditions, DIF and HEO maintain a relatively stable binding state, and the release rate is relatively lower, which is beneficial for maintaining the continuous release of pesticides.

[0034] Further investigation into the near-infrared (Nir) light-responsive release performance revealed that under 1W NIR irradiation at 800nm, HEO nanofibers can absorb light energy and convert it into heat energy. The increased local temperature promotes changes in the carrier structure and intermolecular interaction states, thereby accelerating the release rate of DIF molecules. Compared to the unilluminated condition, the DIF@HEO system exhibits faster release behavior under NIR stimulation, indicating that this carrier possesses photoresponsive release regulation capabilities.

[0035] The results show that the Zn-Co-Fe-Cu-Gd high-entropy oxide nanofiber loading system constructed in this invention can simultaneously respond to disease-related acidic environments and external near-infrared light stimulation. By synergistically regulating pesticide release through pH response and photothermal response, it can achieve continuous, controllable, and on-demand pesticide release, improve pesticide utilization efficiency, and reduce losses in non-target environments.

[0036] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-entropy nanocarrier controlled-release pesticide, characterized in that, The controlled-release pesticide includes a pentagonal high-entropy oxide nanofiber carrier composed of Zn, Co, Fe, Cu and Gd obtained by electrospinning, and at least one pesticide loaded on the carrier.

2. The controlled-release pesticide according to claim 1, characterized in that, The pesticides include difenoconazole, tebuconazole, hexaconazole, azoxystrobin, pyraclostrobin, and carbendazim, with a pesticide loading of 25-30 wt%.

3. The controlled-release pesticide according to claim 1, characterized in that, The molar ratio of Zn, Co, Fe, Cu and Gd in the nanofiber carrier is 1:1:1:1:

1.

4. The method for preparing the high-entropy nanocarrier controlled-release pesticide according to any one of claims 1-3, characterized in that, The method described: Step 1: Dissolve the metal salts of zinc, cobalt, iron, copper and gadolinium in N,N-dimethylformamide in an equimolar ratio, then add polyvinylpyrrolidone, mix and stir to obtain a homogeneous and stable precursor solution; Step 2: Electrospin the precursor solution under a high voltage electrostatic field to obtain continuous precursor nanofibers; Step 3: Place the precursor nanofibers in a tube furnace and calcine them in an air atmosphere to obtain Zn-Co-Fe-Cu-Gd high-entropy oxide nanofibers with a porous structure. Step 4: Mix the obtained nanofibers with pesticides under stirring to obtain high-entropy nanocarrier controlled-release pesticides.

5. The preparation method according to claim 4, characterized in that, In step 1, the concentration of polyvinylpyrrolidone in the precursor solution is 0.1-0.2 g / mL, and the concentration of zinc metal salt in the precursor solution is 0.004-0.006 g / mL.

6. The preparation method according to claim 4, characterized in that, In step 2, the electrospinning parameters are as follows: the distance between the nozzle and the receiver is 10-15cm, the voltage is 16-19kV, and the feed rate is 1-1.5mL / h.

7. The preparation method according to claim 4, characterized in that, In step 3, the calcination temperature is 350-450℃, and the holding time is 1.5-2.5h.

8. The preparation method according to claim 4, characterized in that, In step 4, the mass ratio of nanofibers to pesticides is 1:(14-16).

9. The application of the high-entropy nanocarrier controlled-release pesticide according to any one of claims 1-3, characterized in that, The controlled-release pesticide is used in the field of crops.

10. The application according to claim 9, characterized in that, Crops include soybeans.

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