Amino acid-based nanopharmaceutical fertilizer composite material, preparation method and application thereof

Abstract

The present invention provides a nano-pesticide-fertilizer composite material based on amino acids, its preparation method and application, and belongs to the technical field of pesticide slow-release. The present invention utilizes amino acids as organic ligands, and metal iron ions are doped into amino acids as cross-linking nodes by a hydrothermal method, and a template agent or an auxiliary organic ligand is used as an additive to obtain amino acid-iron complex nanocarriers with large pores, high specific surface area, and biodegradable. The pesticide raw material is then loaded into the amino acid-iron complex nanocarrier by adsorption, and a nano-pesticide composite system with slow / controlled release, degradability, and environmental friendliness is constructed. The system can effectively control the growth of Rhizoctonia solani, improve the bactericidal activity against Rhizoctonia solani, enhance the use efficiency of the pesticide, and reduce the pollution that the pesticide may cause to the environment, and provide good nutritional functions for plants.

Description

Technical Field

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

[0002] Pesticides are critical agricultural inputs that protect seeds and crops from harmful plants, insects, bacteria, fungi, and rodents. They continue to play a vital role in safeguarding global crop health and increasing harvests. Global pesticide use continues to grow, and with global population growth and climate change, global pesticide use is expected to continue to increase in the future. The root cause of this widespread use of pesticides is their extremely low effective utilization rate. Once applied to a target surface, virtually all pesticides enter the environment, causing severe pollution to soil, water, and air.

[0003] The development of nanotechnology has provided a new strategy for addressing these issues, as it offers unique advantages such as small size effects, large surface areas, and excellent water dispersibility and adhesion. Metal-organic frameworks (MOFs) are considered excellent carriers for nanopesticides due to their high surface area, high porosity, adjustable pore size, abundant active sites, simple synthesis methods, and scalable synthesis. Furthermore, the metal ions (such as zinc, iron, copper, calcium, and magnesium) contained in MOFs 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 a stable and sustained supply of metal ions through a controlled-release mechanism, promoting healthy crop growth. However, the organic ligands, as the primary components of conventional MOFs, generally play no role in crop growth. Furthermore, some organic ligands (such as polyphenyls and nitrogen- or sulfur-containing groups) may be toxic upon contact with organisms. In recent years, with growing awareness of environmental sustainability, the use of natural organic molecules (such as organic acids, amino acids, and sugars) as ligands has been shown to reduce toxicity to the environment and organisms to a certain extent. Natural organic molecules are generally biodegradable, are less likely to accumulate in the environment over long periods of time, and have extremely low ecotoxicity.

[0004] As regulatory factors for plant growth, amino acids have multiple roles, including promoting plant growth and development, enhancing stress resistance, improving photosynthesis and nutrition, accelerating 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, making them suitable organic ligands for MOFs. However, there is currently little research on amino acid MOFs as drug carriers. A key factor is that the pore structure of amino acid MOFs is generally relatively compact, especially compared to 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 and certain macromolecular botanical pesticides) may not be able to fully enter these small pores, resulting in low drug loading and limiting their application as drug carriers.

[0005] Broad-spectrum fungicides such as fluazinam (Flu) are poorly water-soluble and easily photodegraded. Long-term use can lead to drug resistance in pathogens. Therefore, developing a safe, controlled-release nanofungicide to increase the effective utilization of the original drug is a daunting challenge. Summary of the Invention

[0006] The purpose of the present invention is to provide an amino acid-based nanopharmaceutical fertilizer composite material, 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 slow-release and growth-promoting 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 an amino acid-based nanopharmaceutical-fertilizer composite material, comprising the following steps:

[0009] The iron salt, amino acid, additive, water and organic solvent are mixed and compounded 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 nanopesticide-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; and the mass ratio of the amino acid to the ionic template 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 azoxystrobin.

[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 solution.

[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 method for preparing an amino acid-based nanopharmaceutical fertilizer composite material. The method utilizes amino acids as organic ligands, and metal iron ions are doped into the amino acids as cross-linking nodes through a hydrothermal method. An ionic template or an auxiliary organic ligand is used as an additive. The template provides rigid support in the framework of the amino acid and iron coordination. By removing the template, the pores in the framework are expanded. The auxiliary ligand utilizes its inherent rigidity to coordinate with the iron ions and is doped into the framework of the amino acid and iron coordination, thereby expanding the pores. Thus, the present invention obtains amino acid-iron composite nanocarriers with large pores, high specific surface area, and biodegradability by changing the pore structure, thereby increasing the drug loading capacity. The pesticide is then loaded into the amino acid-iron composite nanocarriers by adsorption, constructing a nanopesticide composite system that can be slow / controlled-released, degradable, and environmentally friendly. The system has good foliage affinity, can effectively control the growth of pathogenic fungi such as Rhizoctonia solani, and improves the fungicidal 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, thereby releasing the pesticide in the skeleton. The infected pests secrete bioacids to provide an acidic environment, and the intestinal tract of the pests is a weakly 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 nanopesticide-fertilizer composite material of the present invention are rich in amino and carboxyl groups, and can form hydrogen bonds with leaf surfaces in the form of an aqueous dispersion, thereby improving the affinity and deposition rate of pesticides on the leaf surfaces. Moreover, amino acids, as bioregulators, can be degraded and utilized by biological enzymes in organisms, making them a degradable and environmentally friendly material. BRIEF DESCRIPTION OF THE DRAWINGS

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

[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+ )@Flu contact angle on potato leaves;

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

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

[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] Figure 9 Fluazinam technical, deionized water, BD-PA (Fe 3+ ) and BD-PA(Fe 3+ )@Flu contact angle on potato leaves;

[0034] Figure 10 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 an amino acid-based nanopharmaceutical-fertilizer composite material, comprising the following steps:

[0037] The iron salt, amino acid, additive, water and organic solvent are mixed and compounded 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 nanopesticide-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 compound containing nitrogen or carboxyl groups.

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

[0042] The present invention preferably dissolves an iron salt in a mixture of water and an organic solvent to obtain an iron salt solution; disperses an amino acid and an additive in the mixture of water and an organic solvent; and adds the resulting mixture containing the amino acid and the additive dropwise to the iron salt solution under continuous stirring. After the dropwise addition is complete, the mixture is stirred in a sealed container for reaction. The present invention does not specifically limit the total amount of the water and organic solvent used, and can be adjusted as needed 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 hours, more preferably 48 hours.

[0044] After the complexation is completed, the present invention preferably centrifuges the resulting product for 10 minutes to collect the solid, and then repeatedly washes it with deionized water and methanol to remove excess unreacted iron salts and additives, thereby obtaining 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 nitrogen atom of the amino group and the oxygen atom of the carboxyl group of the amino acid, thereby forming a coordinated bond.

[0045] In the present invention, the pesticide technical preferably includes a fungicide with a broad-spectrum effect, and the pesticide technical preferably includes fluazinam, prochlorperamide, hexaconazole, pyraclostrobin or azoxystrobin; 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 to 40° C., more preferably 25° C., and the time is preferably 12 to 96 hours, more preferably 48 hours.

[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 (methanol to water volume ratio of 1:1), and vacuum-dries it at 60° C. for 12 h to obtain an amino acid-based nanopharmaceutical 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 solution.

[0051] The present invention provides the application of the amino acid-based nanopesticide-fertilizer composite material in the pesticide field. The present invention has no particular 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 scope of protection 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 making creative work are within the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are all 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 collected by centrifugation for 10 minutes and washed repeatedly 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 nanostructured system loaded with the 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 of 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 dried in vacuo 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. Other aspects are the same as in 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, with a particle size of 129.8±16.2nm.

[0064] 2) PA(Fe 3+ )@Flu and CTAB-PA(Fe in Example 1 3+ )@Flu nanoparticles were loaded with 10 mg of PA(Fe 3+ )@Flu or CTAB-PA(Fe 3+ )@Flu was placed in a 50mL centrifuge tube, 20mL of methanol was added, the tube was sealed and placed in an ultrasonicator for 4 hours, and then centrifuged at 7800 rpm for 10 minutes. The supernatant was collected and the fluazinam content was analyzed by HPLC. The nanoparticle drug loading efficiency was calculated using the formula: Fluazinam drug loading efficiency (%) = mass of fluazinam in the nanoparticle system (g) / total mass of the nanoparticle system (g) × 100%.

[0065] The HPLC detection conditions of fluazinam are as follows: mobile phase: methanol: water = 90:10, injection volume: 10 μL, detection wavelength: 245 nm, column temperature: 25°C, retention time: 5 min. 3+ )@Flu has a drug loading of 41.80%, while the 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 nanocarriers.

[0067] 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).

[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+ The hydrated particle size of )@Flu increased to 364.4±6.7nm, and it also had excellent water dispersibility with a PDI of 0.22±0.050. 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 44.70±1.10mV. The negative charge is caused by the electronic effect of the fluorine atoms, nitrogen atoms and aromatic ring groups in the structure of fluazinam and its ionization characteristics in the solution. 3+ )@Flu's zeta potential dropped to 29.10±0.40 mV.

[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 and -OH on -COOH of phenylalanine. After loading fluazinam, CTAB-PA(Fe 3+ )@Flu on 3389cm -1 and 1505cm -1 The stretching 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+ ) on. 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 nanopesticide composite system.

[0072] 5) Fluazinam technical, 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 technical, 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 the fluazinam 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, thereby enhancing the affinity of fluazinam technical with the leaves and reducing the loss of pesticides in actual use. 3+ )@Flu has a higher contact angle than CTAB-PA(Fe 3+ The reason for the high ) may be that the fluazinam adsorbed on the outer surface of the nanoparticles buries some amino and carboxyl groups, but 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. First, different masses of CTAB-PA(Fe 3+)@Flu was incorporated into PDA culture 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 had grown all over the plate, the diameters of the colonies on other plates were measured using the cross-cross method. The CTAB-PA(Fe) was calculated based on the colony diameters. 3+ Relative inhibition rate of @Flu against Rhizoctonia solani. Fluazinam technical was used as the control experimental group. The inhibition rate of the 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 technical 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 culture medium. After fluazinam was mixed into PDA culture medium, fluazinam recrystallized and precipitated, resulting in uneven distribution in the culture medium. 3+) nanoparticles, its water dispersibility is improved so that it 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 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. The solid was collected by centrifugation for 10 minutes and washed repeatedly 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 nanostructured system loaded with the 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, which was recorded 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. Other aspects are the same as Example 2. 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 (A) and particle size distribution (B) of nanoparticles; 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+ ) increased in particle size.

[0089] 2) PA(Fe 3+ )@Flu and BD-PA(Fe prepared in Example 2 3+ )@Flu nanoparticles were loaded with drugs. Weigh 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 centrifuged at 7800rpm for 10 minutes to obtain the supernatant. The fluazinam component was detected by high-performance liquid chromatography and the nanoparticle drug loading rate was calculated using the formula. The high-performance liquid chromatography detection conditions of fluazinam were: mobile phase: methanol: water = 90:10, injection volume of 10μL, detection wavelength of 245nm, column temperature of 25℃, and retention time of 5min. After testing, BD-PA(Fe 3+ )@Flu has a drug loading of 47.56%, while the PA(Fe 3+ ) carrier drug loading capacity is 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 nanocarriers. 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).

[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 technical is 0.75±0.17, which indicates that the dispersion of fluazinam technical in aqueous solution is extremely heterogeneous. 3+ ) has a hydrated particle size of 196.0±1.8nm and has excellent water dispersibility and is monodispersed. Its PDI is 0.032±0.008, which is due to the 3+ ) in the phenylalanine ligand is rich in amino and carboxyl groups. After loading fluazinam, BD-PA (Fe 3+ )@Flu's hydrated particle size increased to 295.4±7.5nm, and it also had 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+ )@Flu's zeta potential dropped to 21.30±1.59 mV.

[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 and -OH on -COOH of phenylalanine. After loading fluazinam, BD-PA (Fe 3+ )@Flu on 3391cm -1 and 1506cm -1 The stretching 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+ ) on. 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 nanopesticide 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 Figure 9 .

[0097] Figure 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. Figure 9 It can be seen that after the sample contacts the potato leaves, its contact angle gradually decreases 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 the fluazinam loaded onto CTAB-PA (Fe 3+ ) can enhance the adhesion of fluazinam to leaves. This may be because BD-PA (Fe 3+ ) The 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. This 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 incorporated into PDA culture 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 had grown all over the plate, the diameters of the colonies on other plates were measured using the cross-cross method, and the BD-PA(Fe) was calculated based on the colony diameters. 3+ Relative inhibition rate of @Flu against Rhizoctonia solani. Fluazinam technical was used as the control experimental group. The inhibition rate of the 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] Figure 10 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] Figure 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 is improved so that they can be evenly distributed in the culture medium, BD-PA(Fe 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 Figure 10 The nanosystems loaded with fluazinam were better than the original drug in controlling Rhizoctonia solani, indicating that the amino acid-based nanopharmaceutical 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, thereby controlling the growth of the disease. However, the original drug does not have sustained and controlled release properties, but is a burst release, and the unstable characteristics of the original drug lead to its inability to effectively 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 principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a nano-pharmaceutical 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 and compounded 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 nanopesticide-fertilizer composite material; The additive is an ionic template or an auxiliary organic ligand; The mixing of the iron salt, amino acid, additive, water and organic solvent comprises: dissolving the iron salt in a mixture of water and organic solvent to obtain an iron salt solution; Dispersing the amino acid and the additive in a mixture of water and an organic solvent, and adding the resulting mixture containing the amino acid and the additive dropwise into the iron salt solution under continuous stirring; The amino acid is an amino acid containing a polycyclic heterocycle; The ionic template includes hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride or sodium lauryl sulfate; The auxiliary organic ligand includes 4,4'-bipyridine, terephthalic acid or trimesic acid; 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 100-10000:1; The compounding temperature is 25-150° C., and the compounding time is 12-96 hours.

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 2, characterized in that The amino acids include phenylalanine, tryptophan, tyrosine or proline.

4. 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.

5. The preparation method according to claim 4, characterized in that The pesticide technical includes fluazinam, imidazole, hexaconazole, pyraclostrobin or azoxystrobin.

6. 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 the pesticide technical in the dispersant is 1-25 mg / mL; the loading temperature is 20-40° C., and the loading time is 12-96 hours.

7. The amino acid-based nanopharmaceutical-fertilizer composite material prepared by the preparation method according to any one of claims 1 to 6.

8. Application of the amino acid-based nanopharmaceutical-fertilizer composite material according to claim 7 in the field of pesticides.

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