Nano pesticide-fertilizer composite material based on amino acid as well as preparation method and application of nano pesticide-fertilizer composite material

Abstract

The invention provides a nano pesticide-fertilizer composite material based on amino acid as well as a preparation method and application thereof, and belongs to the technical field of pesticide slow release. According to the preparation method, amino acid is used as an organic ligand, metal iron ions are used as cross-linking nodes to be doped into the amino acid through a hydrothermal method, and a template agent or an auxiliary organic ligand is used as an additive, so that the biodegradable amino acid-iron compound nano-carrier with large pores and high specific surface area is obtained; the amino acid-iron compound nano-carrier is used as a raw material, and then the pesticide raw material is loaded into the amino acid-iron compound nano-carrier in an adsorption manner, so that a slow / controlled release, degradable and environment-friendly nano-pesticide compound system is constructed, the growth of rhizoctonia solani can be effectively controlled, the bactericidal activity of rhizoctonia solani is improved, and the application prospect is wide. And moreover, the use efficiency of the pesticide is enhanced, the possible pollution of the pesticide to the environment is reduced, and a good nutritional function can be provided for plants.

Description

Technical Field

[0001] The invention relates to the technical field of pesticide sustained-release technology, and in particular to an amino acid-based nanometer drug-fertilizer composite material and a preparation method and application thereof. Background Art

[0002] Pesticides are key agricultural inputs that protect seeds and crops from harmful plants, insects, bacteria, fungi and rodents. Pesticides still play an important role in protecting global crop health and increasing yields. Pesticide use around the world is still on an upward trend. With global population growth and climate change, global pesticide use will continue to increase in the future. The root cause of the large-scale use of pesticides is the extremely low actual effective utilization rate. Once pesticides are applied to the target surface, almost all of them will enter the environment and cause serious environmental pollution, including soil, water and air.

[0003] The development of nanotechnology has provided a new strategy to solve the above problems, because nanotechnology has unique advantages, such as small size effect, large specific surface area, excellent water dispersibility and adhesion. Metal organic frameworks (MOFs) are considered to be excellent choices for nano pesticide carriers because of their high specific surface area, high porosity, adjustable pore size, rich active sites, simple synthesis method, and large-scale synthesis. In addition, the metal ions (such as zinc, iron, copper, calcium, magnesium, etc.) in metal organic frameworks are trace elements required for plant growth and can directly provide these essential nutrients to crops. As fertilizer carriers or nutrient delivery systems, MOFs can provide plants with stable and continuous metal ions through a controlled release mechanism, promoting the healthy growth of crops. However, the organic ligands of traditional MOFs as the main components usually do not play a role in the growth of crops. What's more, some organic ligands (such as polyphenyls, nitrogen-containing or sulfur-containing groups) may have certain toxicity after contact with organisms. In recent years, as people's awareness of environmental sustainability has increased, choosing natural organic molecules (such as organic acids, amino acids, sugars, etc.) as ligands can reduce toxicity to the environment and organisms to a certain extent. Natural organic molecules usually have good biodegradability, are not easy to accumulate in the environment for a long time, and have extremely low ecotoxicity.

[0004] As a regulatory factor of plant growth, amino acids have many functions, such as promoting plant growth and development, enhancing stress resistance, improving photosynthesis and nutrition, promoting flowering and fruit development, improving crop quality and promoting root growth. Amino acids are rich in amino and carboxyl groups and can form stable coordination bonds with metal ions, which makes it possible for them to be used as organic ligands for MOFs. However, there is currently little research on amino acid MOFs as drug carriers. The key factor is that the pore structure of amino acid MOFs is usually relatively tight, especially compared with some traditional MOFs, and their pore size may be smaller, which directly affects their drug loading capacity. For example, some larger molecular drugs (such as macromolecular proteins, some macromolecular plant-derived pesticides, etc.) may not be able to fully enter these small pores, resulting in low drug loading, which limits their application as drug carriers.

[0005] Broad-spectrum fungicides such as Fluazinam (Flu) have poor water solubility and are easily degraded by light. Long-term use can lead to drug resistance in pathogens. Therefore, it is a daunting challenge to develop a safe and controlled-release nanofungicide to improve the effective utilization of the original drug. Summary of the invention

[0006] The object of the present invention is to provide an amino acid-based nano-pharmaceutical-fertilizer composite material and a preparation method and application thereof, which has the characteristics of multi-response (pH, redox), in vivo metabolism, and plant growth promotion, can give pesticides controlled release and growth promotion capabilities, and enhance their bactericidal properties.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a nano-medicine-fertilizer composite material based on amino acids, comprising the following steps:

[0009] The iron salt, amino acid, additive, water and organic solvent are mixed to obtain an amino acid-iron complex;

[0010] The amino acid-iron complex is mixed with the pesticide original drug and a dispersant, and loaded to obtain an amino acid-based nanopharmaceutical-fertilizer composite material;

[0011] The additive is an ionic template or an auxiliary organic ligand.

[0012] Preferably, the iron salt includes ferric chloride, ferric nitrate or ferric sulfate; and the molar ratio of the iron salt to the amino acid is 0.5 to 4:1.

[0013] Preferably, the amino acid is an amino acid containing a polycyclic heterocycle; the ionic template includes hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride or sodium dodecyl sulfate; and the auxiliary organic ligand includes 4,4'-bipyridine, terephthalic acid or trimesic acid.

[0014] Preferably, the amino acid includes phenylalanine, tryptophan, tyrosine or proline; the molar ratio of the amino acid to the auxiliary organic ligand is 0.5 to 5:1; the mass ratio of the amino acid to the ionic template agent is 100 to 10000:1.

[0015] Preferably, the compounding temperature is 25 to 150° C. and the compounding time is 12 to 96 hours.

[0016] Preferably, the pesticide technical is a fungicide; and the mass ratio of the amino acid-iron complex to the pesticide technical is 1:0.5-4.

[0017] Preferably, the pesticide technical includes fluazinam, imidazole, hexaconazole, pyraclostrobin or myclobutanil.

[0018] Preferably, the dispersant is a methanol-water mixed solvent; the volume ratio of the methanol to water is 0.5 to 2:1; and the concentration of fluazinam in the dispersant is 1 to 25 mg / mL.

[0019] Preferably, the load temperature is 20-40° C. and the time is 12-96 hours.

[0020] The present invention provides an amino acid-based nano-medicine-fertilizer composite material prepared by the preparation method described in the above technical scheme.

[0021] The present invention provides the application of the amino acid-based nano-pesticide-fertilizer composite material described in the above technical solution in the field of pesticides.

[0022] The present invention provides a preparation method of a nano-pharmaceutical fertilizer composite material based on amino acids, using amino acids as organic ligands, and doping metal iron ions as cross-linking nodes into amino acids by a hydrothermal method, and using ionic templates or auxiliary organic ligands as additives, the templates provide rigid support in the framework of amino acids and iron coordination, and the effect of expanding the pores in the framework is achieved by removing the templates. The role of the auxiliary ligand is to coordinate with iron ions by using the rigid structure of its structure itself, and to be doped into the framework of amino acids and iron ions coordination, thereby achieving the effect of expanding the pores. Therefore, the present invention obtains amino acid-iron composite nano-carriers with large pores, high specific surface area, and biodegradable by changing the pore structure, thereby increasing the drug loading; then the pesticide original drug is loaded into the amino acid-iron composite nano-carrier by adsorption, and a nano-pesticide composite system that can be slow / controlled release, degradable, and environmentally friendly is constructed, which has good leaf surface affinity, can effectively control the growth of pathogenic fungi such as Rhizoctonia solani, and improves the bactericidal activity against pathogenic fungi such as Rhizoctonia solani. In addition, the amino acid ligands and iron ions contained in the nanocarriers can regulate plant growth, effectively promote plant growth, enhance the efficiency of pesticide use, reduce the possible pollution of pesticides to the environment, and provide good nutritional functions for plants.

[0023] The metal coordination bonds in the amino acid-iron skeleton prepared by the present invention can be destroyed by acid or alkaline environment, so as to release the pesticide in the skeleton. The infected pests secrete biological acid to provide an acidic environment, and the intestinal tract of the pests is a weak alkaline environment. 3+ It will also be reduced by reducing agents such as reduced glutathione and hydrogen peroxide in the pathogenic body. 2+ , thereby controlling the release of loaded pesticides.

[0024] The amino acid ligands in the nano-pesticide-fertilizer composite material of the present invention are rich in amino and carboxyl groups, and can form hydrogen bonds with leaf surfaces in the state of aqueous dispersion, thereby improving the affinity and deposition rate of pesticides on the leaf surfaces; and amino acids, as bioregulators, can be degraded and utilized by biological enzymes in organisms, and are degradable and environmentally friendly materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 CTAB-PA(Fe 3+ ) Scanning electron microscopy image of nanoparticles (A) and particle size distribution (B);

[0026] Figure 2 CTAB-PA(Fe 3+ ) and CTAB-PA(Fe 3+ )@ Flu nanoparticles hydrated particle size diagram (A) and its zeta potential diagram with fluazinam original drug (B);

[0027] Figure 3 FluTC, CTAB-PA (Fe 3+ ) and CTAB-PA(Fe 3+ )Fourier transform infrared spectrum (A) and ultraviolet absorption spectrum (B) of @Flu nanoparticles;

[0028] Figure 4 Fluazinam technical, deionized water, CTAB-PA (Fe 3+ ) and CTAB-PA(Fe 3+ )@Contact angle of Flu on potato leaves;

[0029] Figure 5 Different concentrations of fluazinam original drug (FluTC) and CTAB-PA (Fe 3+ )@Flu nanoparticles bactericidal effect diagram (A) and inhibition curve (B) on Rhizoctonia solani after 4 days;

[0030] Figure 6 BD-PA(Fe 3+ ) Scanning electron microscopy image of nanoparticles (A) and particle size distribution (B);

[0031] Figure 7 BD-PA(Fe 3+ ) and BD-PA(Fe 3+ )@ Flu nanoparticles hydrated particle size diagram (A) and its zeta potential diagram with fluazinam original drug (B);

[0032] Figure 8 Flu TC, BD-PA (Fe 3+ ) and BD-PA(Fe 3+ )Fourier transform infrared spectrum (A) and ultraviolet absorption spectrum (B) of @Flu nanoparticles;

[0033] Fig. 9 Fluazinam original drug, deionized water, BD-PA (Fe 3+ ) and BD-PA(Fe 3+ )@Contact angle of Flu on potato leaves;

[0034] Fig.10 Different concentrations of fluazinam original drug and BD-PA (Fe 3+ )@Flu nanoparticles bactericidal effect diagram (A) and inhibition curve (B) on Rhizoctonia solani after 4 days. DETAILED DESCRIPTION

[0035] In the present invention, unless otherwise specified, the required raw materials or reagents are commercially available products well known to those skilled in the art.

[0036] The present invention provides a method for preparing a nano-medicine-fertilizer composite material based on amino acids, comprising the following steps:

[0037] The iron salt, amino acid, additive, water and organic solvent are mixed to obtain an amino acid-iron complex;

[0038] The amino acid-iron complex is mixed with the pesticide original drug and a dispersant, and loaded to obtain an amino acid-based nanopharmaceutical-fertilizer composite material;

[0039] The additive is an ionic template or an auxiliary organic ligand.

[0040] In the present invention, the iron salt preferably includes ferric chloride, ferric nitrate or ferric sulfate, more preferably ferric chloride hexahydrate; the amino acid is preferably an amino acid containing a polycyclic heterocycle; the amino acid preferably includes phenylalanine, tryptophan, tyrosine or proline; the ionic template preferably includes hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride or sodium dodecyl sulfate; the auxiliary organic ligand preferably includes 4,4'-bipyridine, terephthalic acid or trimesic acid; the auxiliary organic ligand is a polycyclic heterocyclic organic substance containing nitrogen or carboxyl.

[0041] In the present invention, the molar ratio of the iron salt to the amino acid is preferably 0.5-4:1, more preferably 1:1; the molar ratio of the amino acid to the auxiliary organic ligand is preferably 0.5-5:1, more preferably 1:1; the mass ratio of the amino acid to the ionic template is preferably 100-10000:1, more preferably 1000:1; the organic solvent is preferably N,N-dimethylformamide; the volume ratio of water to the organic solvent is preferably 1:0.5-2, more preferably 1:1.

[0042] The present invention preferably dissolves the iron salt in a mixture of water and an organic solvent to obtain an iron salt solution; disperses the amino acid and the additive in the mixture of water and the organic solvent, and drips the obtained mixture containing the amino acid and the additive into the iron salt solution drop by drop under continuous stirring, and stirs the reaction in a sealed container after the dripping is completed. The present invention has no special limitation on the total amount of the water and the organic solvent, and can be adjusted according to demand to ensure sufficient dispersion.

[0043] In the present invention, the compounding temperature is preferably 25 to 150° C., more preferably 110° C.; the compounding time is preferably 12 to 96 h, more preferably 48 h.

[0044] After the compounding is completed, the present invention preferably centrifuges the obtained product for 10 minutes to collect the solid, and repeatedly washes it with deionized water and methanol to remove excess unreacted iron salts and additives to obtain an amino acid-iron complex. In the amino acid-iron complex of the present invention, the iron ion forms a metal coordination bond with the N atom on the amino group and the O on the carboxyl group in the amino acid, and is combined in a coordinated form.

[0045] In the present invention, the pesticide technical preferably includes a fungicide with a broad-spectrum effect, and the pesticide technical preferably includes fluazinam, imidazole, hexaconazole, pyraclostrobin or myclobutanil; the mass ratio of the amino acid-iron complex to the pesticide technical is preferably 1:0.5-4, more preferably 1:1.

[0046] In the present invention, the dispersant is preferably a methanol-water mixed solvent; the volume ratio of methanol to water is preferably 0.5-2:1, more preferably 1:1; the concentration of fluazinam in the dispersant is preferably 1-25 mg / mL, more preferably 5.0 mg / mL.

[0047] In the present invention, the pesticide technical is preferably dispersed in a dispersion solvent, the obtained dispersion is mixed with the amino acid-iron complex, and the loading is performed under stirring conditions.

[0048] In the present invention, the temperature of the load is preferably 20-40° C., more preferably 25° C., and the time is preferably 12-96 h, more preferably 48 h.

[0049] After completing the loading, the present invention preferably centrifuges the obtained product, washes it 2 to 3 times with a methanol-water mixed solvent (the volume ratio of methanol to water is 1:1), and vacuum dries it at 60° C. for 12 hours to obtain an amino acid-based nano-medicine-fertilizer composite material.

[0050] The present invention provides an amino acid-based nano-medicine-fertilizer composite material prepared by the preparation method described in the above technical scheme.

[0051] The present invention provides the application of the amino acid-based nano-pesticide-fertilizer composite material in the field of pesticides. The present invention has no special limitation on the application method, and the application can be carried out according to methods well known in the art.

[0052] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified.

[0053] The following experimental methods and detection methods, unless otherwise specified, are conventional methods; the following reagents and raw materials, unless otherwise specified, are commercially available.

[0054] Example 1

[0055] 1) CTAB-PA(Fe 3+ )

[0056] 540.6 mg of ferric chloride hexahydrate was dissolved in a mixed solvent of 10 mL of water and N,N-dimethylformamide in a volume ratio of 1:1 to obtain a ferric chloride solution. 330.4 mg of phenylalanine (PA) and 0.3304 mg of hexadecyltrimethylammonium bromide (CTAB) were dissolved in a mixed solvent of 20 mL of water and N,N-dimethylformamide in a volume ratio of 1:1. The resulting mixture was added dropwise to the ferric chloride solution under continuous stirring. After the addition was completed, the mixture was placed in a sealed container and stirred at 110°C for 48 hours. The solid was taken out and centrifuged for 10 minutes to collect the solid, which was repeatedly washed with deionized water and ethanol to obtain an amino acid-iron complex, recorded as CTAB-PA (Fe 3+ ).

[0057] 2) CTAB-PA(Fe 3+ ) Preparation of nanoparticle system loaded with pesticide fluazinam

[0058] Dispersing fluazinam in a mixed solvent of methanol and water in a volume ratio of 1:1, wherein the concentration of fluazinam in the mixed solvent is 5.0 mg / mL, to obtain a dispersion containing fluazinam;

[0059] Weigh 100 mg CTAB-PA (Fe 3+ ) in a round-bottom flask, add 20 mL of the dispersion containing fluazinam, fluazinam and CTAB-PA (Fe 3+ ) in a mass ratio of 1:1, stirred at 25°C for 48 h, centrifuged, washed three times with a mixed solvent of methanol and water in a volume ratio of 1:1, and vacuum dried at 60°C for 12 h to obtain a nanomaterial loaded with fluazinam, which was designated as CTAB-PA(Fe 3+ )@Flu.

[0060] Comparative Example 1

[0061] The only difference from Example 1 is that CTAB is not added. The other aspects are the same as Example 1. The carrier PA (Fe 3+ ) and the corresponding PA(Fe 3+ )@Flu.

[0062] Characterization and testing

[0063] 1) Figure 1 CTAB-PA(Fe 3+)Scanning electron microscopy image (A) and particle size distribution (B) of nanoparticles; Figure 1 It can be seen that CTAB-PA(Fe 3+ ) The nanoparticles are uniform and regular spherical, and their particle size is 129.8±16.2nm.

[0064] 2) PA(Fe 3+ )@Flu and CTAB-PA(Fe in Example 1 3+ )@Flu nanoparticles were used to measure the drug loading rate: 10 mg PA(Fe 3+ )@Flu or CTAB-PA(Fe 3+ )@Flu was placed in a 50mL centrifuge tube, 20mL of methanol was added, the centrifuge tube was sealed and placed in an ultrasonic generator for 4 hours, and then the supernatant was taken after centrifugation at 7800rpm for 10 minutes. The fluazinam component was detected by high performance liquid chromatography and the nanoparticle loading rate was calculated using the formula. Fluazinam loading rate (%) = mass of fluazinam in the nanosystem (g) / total mass of the nanosystem (g) × 100%.

[0065] The HPLC detection conditions of fluazinam are as follows: mobile phase: methanol: water = 90:10, injection volume of 10 μL, detection wavelength of 245 nm, column temperature of 25°C, retention time of 5 min. 3+ )@Flu has a drug loading of 41.80%, while PA(Fe 3+ )@Flu drug loading is only 6.41%, indicating that the template carrier CTAB-PA (Fe 3+ ) Large pores and higher specific surface area.

[0066] 3) Figure 2 Table 1 shows the hydrated particle size, polymer dispersion index PDI and Zeta potential of the nanocarrier.

[0067] Figure 2 CTAB-PA(Fe 3+ ) and CTAB-PA(Fe 3+ )@Flu nanoparticles’ hydrated particle size diagram (A) and its zeta potential diagram compared with fluazinam original drug (B).

[0068] Table 1 Fluazinam technical, CTAB-PA (Fe 3+ ) and CTAB-PA(Fe 3+ )@Flu nanoparticle size and Zeta potential parameters

[0069]

[0070] Depend on Figure 2 As shown in Table 1, CTAB-PA(Fe 3+ ) has a hydrated particle size of 215.3±2.9nm and has excellent water dispersibility with a PDI of 0.040±0.0060, which is due to the 3+ ) is rich in amino and carboxyl groups. After loading fluazinam, CTAB-PA (Fe 3+ )@Flu hydrated particle size increased to 364.4±6.7nm, and also had excellent water dispersibility, with a PDI of 0.22±0.050. In a neutral environment, due to the rich Fe 3+ Therefore, the Zeta charge of the nanocarrier is positive, and its potential is 44.70±1.10mV. The negative charge is caused by the electronic effect of the fluorine atom, nitrogen atom and aromatic ring group in the structure of fluazinam and its ionization characteristics in the solution. 3+ )@The Zeta potential of Flu decreased to 29.10±0.40mV.

[0071] 4) Figure 3 Flu TC, CTAB-PA (Fe 3+ ) and CTAB-PA(Fe 3+ )@Flu nanoparticles Fourier transform infrared spectrum (A) and ultraviolet absorption spectrum (B); Figure 3 As shown in A, 3449cm -1 The absorption peak is the stretching vibration peak of -NH2 on the ligand phenylalanine, 1667cm -1 and 3119cm -1 The absorption peaks are respectively the stretching vibration peaks of C=O on -COOH and -OH on phenylalanine. 3+ )@Flu on 3389cm -1 and 1505cm -1 The stretching vibration and bending vibration peaks of -NH-, which are unique to fluazinam, appeared. In addition, at 1547 cm -1 The bending vibration peak of -NO2, which is unique to fluazinam, also appeared. This shows that fluazinam was successfully loaded on CTAB-PA (Fe 3+ ) Figure 3 As shown in Figure B, the UV absorption peaks at 340 nm and 245 nm come from the π-π stacking of the benzene ring and pyridine ring on fluazinam. 3+ ), CTAB-PA(Fe 3+)@Flu showed the unique ultraviolet absorption peaks of fluazinam at 340nm and 245nm, which also proved that the loading of fluazinam was successful, indicating that CTAB-PA(Fe 3+ )@Flu nano pesticide composite system.

[0072] 5) Fluazinam original drug, CTAB-PA (Fe 3+ ) and CTAB-PA(Fe 3+ )@Flu was prepared into a 1 mg / mL aqueous dispersion and its wetting properties were tested. The results are shown in Figure 4 .

[0073] Figure 4 Fluazinam original drug, deionized water (blank, CK), CTAB-PA (Fe 3+ ) and CTAB-PA(Fe 3+ )@Flu contact angle on potato leaves. Figure 4 It can be seen that after the sample contacts the plant leaves, its contact angle gradually decreases within 1 minute. 3+ ) and CTAB-PA(Fe 3+ )@Flu on the potato leaf surface were 45.79° and 74.06° respectively. The contact angle of fluazinam original drug was 107.92°. The results showed that when fluazinam was loaded onto CTAB-PA(Fe 3+ ) can enhance the adhesion of fluazinam to leaves. This may be because CTAB-PA (Fe 3+ ) The surface of the carrier contains a large number of polar groups such as amino and carboxyl groups, which form hydrogen bonds with the leaf surface, enhancing the affinity of fluazinam original drug with the leaves, thereby reducing the loss of pesticides in actual use. 3+ )@Flu has a higher contact angle than CTAB-PA(Fe 3+ ) may be due to the fact that the fluazinam adsorbed on the outer surface of the nanoparticles entraps some amino and carboxyl groups. However, compared with the fluazinam original drug, CTAB-PA (Fe 3+ )@Flu still has good adhesion on potato leaves.

[0074] 6) Fluazinam original drug (FluTC) and CTAB-PA (Fe 3+ )@Flu was prepared into drug-medium with different mass concentrations, and the plate method was used to test the growth inhibition effect of nanopesticides with different concentration gradients on Rhizoctonia solani. 3+)@Flu was added to the PDA medium to obtain plates with effective concentrations of fluazinam of 0 (blank control, CK), 0.00625, 0.0125, 0.025, 0.05 and 0.1 mg / L. A mycelium sample disk with a diameter of 5 mm was placed upside down in the center of the plate, and then moved to a 25°C incubator for incubation. After the mycelium at a concentration of 0 mg / mL covered the plate, the diameters of the colonies in other plates were measured using the cross method, and the CTAB-PA(Fe 3+ )@Flu's relative inhibition rate against Rhizoctonia solani. Fluazinam original drug was used as the control experimental group. The inhibition rate of nanopesticide on mycelial growth was calculated according to the following formula: Inhibition rate (%) = (colony diameter of experimental group - initial grafted mycelial diameter) / (colony diameter of blank group - initial grafted mycelial diameter) × 100%.

[0075] Figure 5 Different concentrations of fluazinam original drug (FluTC) and CTAB-PA (Fe 3+ )@Flu nanoparticles bactericidal effect diagram (A) and inhibition curve (B) on Rhizoctonia solani after 4 days; Table 2 calculated the bactericidal activity of fluazinam original drug and CTAB-PA (Fe 3+ )@Flu nanoparticles against Rhizoctonia solani at 4 days 50 Numeric value.

[0076] Table 2 Flu TC and CTAB-PA (Fe 3+ )@Flu nanocomposite system antibacterial kinetic equation parameter table

[0077]

[0078] Figure 5 The results in Table 2 show that CTAB-PA(Fe 3+ )@Flu nanoparticles against EC of Rhizoctonia solani 50 The value is 0.018mg / mL, and the EC value of fluazinam original drug against Rhizoctonia solani is 50 The values ​​were 0.056 mg / mL. 3+ )@Flu nanoparticles have a better antibacterial effect on pathogenic Rhizoctonia solani than the original drug. This shows that CTAB-PA(Fe 3+ )@Flu encapsulation enhanced the antibacterial activity of fluazinam. This may be due to the poor solubility of fluazinam original drug in PDA medium. After fluazinam was mixed into PDA medium, fluazinam was recrystallized and precipitated, resulting in uneven distribution in the medium. 3+) nanoparticles, their water dispersibility is improved so that they can be evenly distributed in the culture medium. In addition, during the growth of fungi, acidic substances such as citric acid and oxalic acid are secreted to acidify the environment, as well as some reductases (H2O2 and GSH, etc.), which promote the conversion of fluazinam from CTAB-PA (Fe 3+ )@Flu is continuously released into the environment, maintaining the drug at a certain level, thereby enhancing the CTAB-PA(Fe 3+ )@Flu's efficacy.

[0079] Example 2

[0080] 1) BD-PA(Fe 3+ )

[0081] 540.6 mg of ferric chloride hexahydrate was dissolved in a mixed solvent of 10 mL of water and N,N-dimethylformamide in a volume ratio of 1:1 to obtain a ferric chloride solution; 330.4 mg of phenylalanine (PA) and 312.4 mg of 4,4'-bipyridine (BD) were dissolved in a mixed solvent of 30 mL of water and N,N-dimethylformamide in a volume ratio of 1:1 (wherein the molar ratio of PA to BD was 1:1), and the resulting mixture was added dropwise to the ferric chloride solution under continuous stirring. After the addition was completed, the mixture was placed in a sealed container and stirred at 110°C for 48 hours. After the solid was taken out, it was centrifuged for 10 minutes to collect the solid, and was repeatedly washed with deionized water and methanol to obtain an amino acid-iron complex, recorded as BD-PA (Fe 3+ ).

[0082] 2) BD-PA(Fe 3+ ) Preparation of nanoparticle system loaded with pesticide fluazinam

[0083] Dispersing fluazinam in a mixed solvent of methanol and water in a volume ratio of 1:1, wherein the concentration of fluazinam in the mixed solvent is 5.0 mg / mL, to obtain a dispersion containing fluazinam;

[0084] Weigh 100 mg BD-PA (Fe 3+ ) in a round-bottom flask, add 20 mL of the dispersion containing fluazinam, fluazinam and BD-PA (Fe 3+ ) in a mass ratio of 1:1, stirred at 25°C for 48 h, centrifuged, washed three times with a mixed solvent of methanol and water in a volume ratio of 1:1, and vacuum dried at 60°C for 12 h to obtain a nanomaterial loaded with fluazinam, denoted as BD-PA(Fe 3+ )@Flu.

[0085] Comparative Example 2

[0086] The only difference from Example 2 is that no auxiliary ligand BD is added, and the other parts are the same as Example 2 to obtain PA(Fe 3+) carrier and the corresponding PA(Fe 3+ )@Flu.

[0087] Characterization and testing

[0088] 1) Figure 6 BD-PA(Fe 3+ ) Scanning electron microscopy image of nanoparticles (A) and particle size distribution (B); Figure 6 The results showed that BD-PA (Fe 3+ ) nanoparticles are uniform and regular spherical, with a particle size of 169.7±24.8nm. Due to the dual ligand, BD-PA(Fe 3+ ) has increased in particle size.

[0089] 2) PA(Fe 3+ )@Flu and BD-PA (Fe prepared in Example 2 3+ )@Flu nanoparticles were used to measure the drug loading rate. 10 mg BD-PA(Fe 3+ )@Flu was placed in a 50mL centrifuge tube, 20mL of methanol was added, the centrifuge tube was sealed and placed in an ultrasonic generator for 4 hours, and then the supernatant was taken after centrifugation at 7800rpm for 10 minutes. The fluazinam component was detected by HPLC and the nanoparticle drug loading rate was calculated using the formula. The HPLC detection conditions of fluazinam were: mobile phase: methanol: water = 90:10, injection volume was 10μL, detection wavelength was 245nm, column temperature was 25℃, and retention time was 5min. After testing, BD-PA(Fe 3+ )@Flu has a drug loading of 47.56%, while PA(Fe 3+ ) carrier has a drug loading of only 6.41%, indicating that the present invention uses the auxiliary ligand carrier BD-PA (Fe 3+ ) Large pores and higher specific surface area.

[0090] 3) Figure 7 Table 3 shows the hydrated particle size, polymer dispersion index PDI and Zeta potential of the nanocarrier. Figure 7 BD-PA(Fe 3+ ) and BD-PA(Fe 3+ )@Flu nanoparticles’ hydrated particle size diagram (A) and its zeta potential diagram compared with fluazinam original drug (B).

[0091] Table 3BD-PA (Fe 3+ ) and BD-PA(Fe 3+ )@Flu nanoparticle size and Zeta potential parameter table

[0092]

[0093]

[0094] Depend on Figure 7 As shown in Table 3, the PDI of fluazinam original drug is 0.75±0.17, which indicates that the dispersion of fluazinam original drug in aqueous solution is extremely heterogeneous. 3+ ) has a hydrated particle size of 196.0±1.8nm and has excellent water dispersibility and is monodisperse. Its PDI is 0.032±0.008, which is due to the fact that BD-PA(Fe 3+ ) is rich in amino and carboxyl groups. After loading with fluazinam, BD-PA (Fe 3+ )@Flu has a hydrated particle size of 295.4±7.5nm and also has excellent water dispersibility with a PDI of 0.18±0.022. 3+ )@Flu In a neutral environment, the surface of the nanocarrier is rich in Fe 3+ Therefore, the Zeta charge of the nanocarrier is positive, and its potential is 38.40±0.85mV. After loading the negatively charged fluazinam, BD-PA (Fe 3+ )@The Zeta potential of Flu decreased to 21.30±1.59mV.

[0095] 4) Figure 8 Flu TC, BD-PA (Fe 3+ ) and BD-PA(Fe 3+ )@Flu nanoparticles Fourier transform infrared spectrum (A) and ultraviolet absorption spectrum (B); Figure 8 As shown in A, 3449cm -1 The absorption peak is the stretching vibration peak of -NH2 on the ligand phenylalanine, 1664cm -1 and 3137cm -1 The absorption peaks are respectively the stretching vibration peaks of C=O on -COOH and -OH on phenylalanine. 3+ )@Flu on 3391cm -1 and 1506cm -1 The stretching vibration and bending vibration peaks of -NH-, which are unique to fluazinam, appeared. In addition, at 1543 cm -1 The bending vibration peak of -NO2, which is unique to fluazinam, also appeared. This shows that fluazinam was successfully loaded on BD-PA (Fe 3+ ) Figure 8As shown in Figure B, the UV absorption peaks at 340 nm and 245 nm come from the π-π stacking of the benzene ring and pyridine ring on fluazinam. 3+ ), BD-PA(Fe 3+ )@Flu also showed the unique ultraviolet absorption peaks of fluazinam at 340nm and 245nm, which also proved that the loading of fluazinam was successful. In summary, Example 2 successfully constructed BD-PA (Fe 3+ )@Flu nano pesticide composite system.

[0096] 5) Fluazinam original drug, BD-PA (Fe 3+ ) and BD-PA(Fe 3+ )@Flu were dispersed in deionized water to form a 1 mg / mL aqueous dispersion, and its wetting properties were tested. The results are shown in Fig. 9 .

[0097] Fig. 9 Fluazinam original drug (Flu TC), deionized water (blank control, CK), BD-PA (Fe 3+ ) and BD-PA(Fe 3 + )@Flu contact angle on potato leaves. Fig. 9 It can be seen that after the sample came into contact with potato leaves, its contact angle gradually decreased within 1 minute. 3+ ) and BD-PA(Fe 3+ )@Flu on the potato leaf surface, the contact angles were 66.75° and 73.24°, respectively. The incorporation of BD resulted in a decrease in the relative content of phenylalanine, which led to the BD-PA(Fe 3+ ) compared with CTAB-PA(Fe 3+ ) was improved. The contact angles of fluazinam original drug were 107.92°. The results showed that fluazinam loaded onto CTAB-PA (Fe 3+ ) can enhance the adhesion of fluazinam to leaves. This may be because BD-PA (Fe 3+ ) A large number of polar groups such as amino and carboxyl groups contained on the surface of the carrier form hydrogen bonds with the surface of the leaves, which enhances the affinity of the fluazinam original drug to the leaves, which can effectively increase the deposition amount of fluazinam on the leaf surface, thereby improving the effective utilization rate of fluazinam.

[0098] 6) The plate method was used to test the growth inhibition effect of nanopesticides with different concentration gradients on Rhizoctonia solani. First, different masses of BD-PA (Fe 3+)@Flu was added to PDA medium to obtain plates with effective concentrations of fluazinam of 0 (blank control CK), 0.00625, 0.0125, 0.025, 0.05 and 0.1 mg / L. A mycelium sample disk with a diameter of 5 mm was placed upside down in the center of the plate, and then moved to a 25°C incubator for incubation. After the mycelium at a concentration of 0 mg / mL covered the plate, the diameters of the colonies in other plates were measured using the cross method, and the BD-PA (Fe 3+ )@Flu's relative inhibition rate against Rhizoctonia solani. Fluazinam original drug was used as the control experimental group. The inhibition rate of nanopesticide on mycelial growth was calculated according to the following formula: Inhibition rate (%) = (colony diameter of experimental group - initial grafted mycelial diameter) / (colony diameter of blank group - initial grafted mycelial diameter) × 100%.

[0099] Fig.10 Different concentrations of fluazinam original drug and BD-PA (Fe 3+ )@Flu nanoparticles bactericidal effect diagram (A) and inhibition curve (B) on Rhizoctonia solani after 4 days; Table 4 calculated the bactericidal activity of fluazinam original drug and BD-PA (Fe 3+ )@Flu nanoparticles against Rhizoctonia solani at 4 days 50 Numeric value.

[0100] Table 4 Fluazinam original drug and BD-PA (Fe 3+ )@Flu nanocomposite system antibacterial kinetic equation parameter table

[0101]

[0102] Fig.10 The results in Table 4 show that BD-PA (Fe 3+ )@Flu nanoparticles against EC of Rhizoctonia solani 50 The value is 0.025mg / mL, and the EC value of the original drug against Rhizoctonia solani is 50 The values ​​were 0.056 mg / mL. 3+ )@Flu nanoparticles have better antibacterial effects on pathogenic Rhizoctonia solani than the original drug. This shows that BD-PA(Fe 3+ )@Flu encapsulation enhanced the antibacterial activity of fluazinam. 3+ ) nanoparticles, their water dispersibility was improved so that they could be evenly distributed in the culture medium. 3+ )@Flu can effectively solve the problem of uneven dispersion caused by poor dispersion of fluazinam original solution. In addition, during the growth of fungi, acidic substances such as citric acid and oxalic acid will be secreted to acidify the microenvironment and secrete some reductases, which will promote the conversion of fluazinam from BD-PA (Fe 3+)@Flu is continuously released into the environment, maintaining the drug at a certain level, thereby enhancing the BD-PA(Fe 3+ )@Flu's efficacy.

[0103] pass Figure 5 and Fig.10 The nanosystems loaded with fluazinam have better control effects on Rhizoctonia solani than the original drug, indicating that the amino acid-based nanomedicine-fertilizer composite material of the present invention has multi-response (pH, redox) characteristics. The reason is that the nanosystem can destroy the coordination bonds in the nanosystem through the biological acid secreted by the disease (Rhizoctonia solani) and the reducing agents such as glutathione and H2O2 can reduce Fe 3+ Reduction to Fe 2+ , destroying the structure of the nanocarrier, thereby maintaining a continuous and stable drug environment, achieving the purpose of sustained and controlled release, and thus controlling the growth of the disease. However, the original drug does not have the performance of sustained and controlled release, but is a sudden release, and the unstable characteristics of the original drug lead to the inability to control the growth of the disease in the long term.

[0104] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a nano-medicine-fertilizer composite material based on amino acids, characterized in that: The following steps are involved: The iron salt, amino acid, additive, water and organic solvent are mixed to obtain an amino acid-iron complex; The amino acid-iron complex is mixed with the pesticide original drug and a dispersant, and loaded to obtain an amino acid-based nanopharmaceutical-fertilizer composite material; The additive is an ionic template or an auxiliary organic ligand.

2. The preparation method according to claim 1, characterized in that: The iron salt includes ferric chloride, ferric nitrate or ferric sulfate; the molar ratio of the iron salt to the amino acid is 0.5-4:

1.

3. The preparation method according to claim 1, characterized in that: The amino acid is an amino acid containing a polycyclic heterocycle; the ionic template agent includes hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride or sodium dodecyl sulfate; and the auxiliary organic ligand includes 4,4'-bipyridine, terephthalic acid or trimesic acid.

4. The preparation method according to claim 3, characterized in that: The amino acid includes phenylalanine, tryptophan, tyrosine or proline; the molar ratio of the amino acid to the auxiliary organic ligand is 0.5-5:1; the mass ratio of the amino acid to the ionic template agent is 100-10000:

1.

5. The preparation method according to claim 1 or 4, characterized in that: The compounding temperature is 25 to 150° C. and the compounding time is 12 to 96 hours.

6. The preparation method according to claim 1, characterized in that: The pesticide technical is a bactericidal pesticide; the mass ratio of the amino acid-iron complex to the pesticide technical is 1:0.5-4.

7. The preparation method according to claim 6, characterized in that: The pesticide technical includes fluazinam, imidazole, hexaconazole, pyraclostrobin or myclobutanil.

8. The preparation method according to claim 1, characterized in that: The dispersant is a methanol-water mixed solvent; the volume ratio of methanol to water is 0.5-2:1; the concentration of fluazinam in the dispersant is 1-25 mg / mL; the loading temperature is 20-40° C., and the loading time is 12-96 hours.

9. The amino acid-based nanomedicine-fertilizer composite material prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the amino acid-based nano-pesticide-fertilizer composite material according to claim 9 in the field of pesticides.

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