Glutathione-responsive organosilica nanocarriers and pesticides containing the same

Abstract

The application discloses a glutathione-responsive organic silicon nano-carrier and pesticide, and adopts the following steps: (1) preparing a mesoporous template agent, which is an aqueous solution of an ethanol phase containing cetyltrimethylammonium bromide; (2) preparing a mixed solution of a mesoporous organic silicon nano-carrier precursor, and the mixed solution contains organosilane with a sulfide bond; (3) adding the mixed solution of step (2) into the aqueous solution of cetyltrimethylammonium bromide obtained in step (1), stirring uniformly, adjusting the system to be alkaline by using ammonia water, centrifuging to obtain solid precipitate, carrying out hydrothermal reaction, centrifuging again, washing the precipitate with water, and drying to obtain a hollow mesoporous organic silicon nano-carrier; the sulfide bond in the shell of the hollow mesoporous organic silicon nano-carrier prepared in the application can have an oxidation-reduction reaction with glutathione in the body of harmful pests, which is helpful to promote the release of the loaded pesticide active ingredient, so that the utilization rate of the drug on the targeted harmful pests is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional pesticide preparation development, and in particular to a glutathione-responsive organic silicon nanocarrier and a pesticide containing the same. BACKGROUND

[0002] In modern agriculture, pesticides play an irreplaceable role in crop pest control and yield. However, during the application process, the use efficiency of pesticides is reduced due to factors such as leaching, runoff, ultraviolet degradation and rapid evaporation, which increases the cost of pesticide application and also causes serious negative impact on the environment. In recent years, many people have devoted themselves to the development of new pesticide formulations, hoping to improve the target use efficiency of pesticides and reduce the pollution of pesticides to the environment by controlling the release process of pesticides.

[0003] Mesoporous silica is considered an ideal slow-release pesticide carrier material due to its unique physicochemical properties. A large number of studies have shown that using ordinary mesoporous silica material to load pesticides can reduce the release speed of pesticides to some extent and prolong the release time of pesticides, but due to the stability of its structure, it is difficult to achieve precise control of the release process of drugs during use. Therefore, it is of great significance to develop a responsive silicon-based carrier with excellent controlled-release performance. SUMMARY

[0004] Based on the above defects, the present application provides a glutathione-responsive organic silicon nanocarrier and a pesticide containing the same. The nanocarrier helps to precisely control the release process of drugs. The pesticide helps to improve the virulence of the target pests and is environmentally friendly.

[0005] In a first aspect, the present application provides a glutathione-responsive organic silicon nanocarrier, which adopts the following technical solution:

[0006] A glutathione-responsive organic silicon nanocarrier is mainly prepared by the following steps:

[0007] (1) Prepare a mesoporous template agent, which is an aqueous solution containing cetyltrimethylammonium bromide in ethanol phase;

[0008] (2) Prepare a mixed solution of mesoporous organic silicon nanocarrier precursor, which contains organosilane with a thioether bond;

[0009] (3) Add the mixed solution of step (2) to the aqueous solution of cetyltrimethylammonium bromide obtained in step (1), stir uniformly, adjust the system to alkaline with ammonia, centrifuge to obtain solid precipitate, perform hydrothermal reaction, centrifuge again, wash the precipitate with water, and dry to obtain a hollow mesoporous organic silicon nanocarrier.

[0010] By adopting the technical scheme, the hollow mesoporous organosilicon nanocarrier with the shell containing the sulfide bond is obtained by using hexadecyl trimethyl ammonium bromide as a mesoporous template agent, ammonia as a catalyst, a silicon source as an organosilane containing a sulfide bond, hydrolyzing in an ethanol-phase aqueous solution to form a solid organosilicon carrier, removing the inner core part of the organosilicon carrier by a hydrothermal etching method, and removing the mesoporous template agent. The sulfide bond in the organosilicon nanocarrier shell can undergo an oxidation-reduction reaction with glutathione in the body of the harmful pest, accelerate the rupture of the organosilicon shell after contacting the harmful pest, promote the release of the pesticide active ingredient, thereby improving the utilization rate of the drug on the targeted harmful pest, reducing the loss of the drug in the external environment, and reducing the harm to the environment.

[0011] Preferably, in the step (1), the ethanol-phase aqueous solution of the hexadecyl trimethyl ammonium bromide, wherein the ethanol-phase aqueous solution is a mixed solution of ethanol and water in a volume ratio of 1:(2-3); the concentration of the hexadecyl trimethyl ammonium bromide is 1.5-2 g / L.

[0012] By adopting the technical scheme, the ethanol and water are configured in the ethanol-phase aqueous solution in a volume ratio of 1:(2-3), which is helpful to improve the reactivity of the hexadecyl trimethyl ammonium bromide; and the concentration of the hexadecyl trimethyl ammonium bromide is 1.5-2 g / L, so as to improve the size consistency of the subsequent organosilicon nanocarrier.

[0013] Preferably, in the step (2), the mixed solution is a mixed solution of bis-[3-(triethoxysilyl)propyl]tetrasulfide and tetraethyl orthosilicate in a volume ratio of 1:(2-3).

[0014] By adopting the technical scheme, the bis-[3-(triethoxysilyl)propyl]tetrasulfide and the tetraethyl orthosilicate are mixed, both of which are organosilicon precursors, and the mixing of the two is convenient for obtaining the organosilane containing the disulfide bond.

[0015] By adopting the technical scheme, it is helpful to improve the size consistency of the formed nanocarrier.

[0016] Preferably, in the step (3), the dropping speed is controlled to be completed within 2 minutes.

[0017] By adopting the technical scheme, the dropping time is controlled within 2 minutes, so as to ensure the uniformity of the reaction system conditions.

[0018] Preferably, in the step (3), the drying treatment is vacuum drying at 40°C or freeze drying at-80°C.

[0019] By adopting the technical scheme, it is convenient to ensure the reactivity of the drug.

[0020] In a second aspect, the application further provides a pesticide containing the above-mentioned glutathione-responsive organosilicon nanocarrier, which is prepared by the following method:

[0021] configuring a pesticide solution;

[0022] adding the nanocarrier into the pesticide solution, stirring uniformly, and then centrifuging and drying to obtain the pesticide.

[0023] The pesticide prepared by the application can undergo redox reaction with glutathione in the body of harmful pests through the sulfide bond in the shell, thereby accelerating the rupture of the organosilicon shell after contacting the pests, promoting the release of the loaded emamectin benzoate, improving the utilization rate of the drug on the targeted pests, reducing the loss of the drug in the external environment, and reducing the harm to the environment.

[0024] As a preferred, the effective component of the pesticide solution is one of abamectin and emamectin benzoate, the solvent is one of methanol, propanol and dimethylamide, and the mass percentage of the effective component in the pesticide solution is 2-10%.

[0025] As a preferred, the addition amount of the glutathione-responsive silicon-based nanocarrier is 0.5-1% of the weight of the pesticide solution.

[0026] By adopting the above technical solution, the proportion between the nanocarrier and the pesticide solution is appropriate, so that the effective component in the pesticide solution can fully act on the nanocarrier, which is conducive to improving the accuracy of the simulated release.

[0027] In summary, the application has at least one of the following technical effects:

[0028] 1. The application prepares a glutathione-responsive organosilicon nanometer pesticide by using a self-developed method, the morphology of the organosilicon nanocarrier is characterized by a transmission electron microscope (TEM) diagram, and the glutathione responsiveness of the organosilicon nanocarrier loaded with emamectin benzoate is verified by a drug release model experiment.

[0029] 2. In the synthesis of the organosilicon nanocarrier, a mixture of bis-[3-(triethoxysilyl)propyl]tetrasulfide and tetraethyl orthosilicate is used, and a hydrolysis reaction occurs in an alkaline environment to synthesize organosilane with a sulfide double bridge, thereby preparing a nanocarrier with glutathione responsiveness.

[0030] 3. The organosilicon nanocarrier loaded with emamectin benzoate is prepared by using an impregnation method, which is simple in operation and suitable for batch production.

[0031] 4. The organosilicon nanocarrier is prepared by a sol-gel method, and then a hollow mesoporous structure is prepared by a hydrothermal reaction, and the preparation process does not require a multi-step coating process and does not use toxic and strongly corrosive reagents.

[0032] 5. In the pesticide prepared in this application, emamectin benzoate is released faster in 0.1 mM glutathione, indicating that the organosilicon nanopesticide loaded with emamectin benzoate has glutathione responsiveness; 6. In the pesticide prepared in this application, the release rate of emamectin benzoate is fastest under neutral pH conditions, indicating that the organosilicon nanopesticide loaded with emamectin benzoate has pH responsiveness; 7. In the pesticide prepared in this application, the release rate of emamectin benzoate is faster with increasing temperature, which also indicates that the organosilicon nanopesticide loaded with emamectin benzoate has a certain degree of sustained release. Attached Figure Description

[0033] Fig. 1 TEM image used to illustrate unetched organosilicon nanocarriers;

[0034] Fig. 2 TEM image used to illustrate the organosilicon nanocarrier of Example 1;

[0035] Fig. 3 TEM image used to illustrate the nanopesticide loaded with emamectin benzoate in Example 6;

[0036] Fig. 4 The cumulative release rate curves of the pesticide in Example 6 with and without 0.1 mM glutathione are used to illustrate this.

[0037] Fig. 5 The cumulative release rate curve of the pesticide at different pH values ​​is used to illustrate Example 6;

[0038] Fig. 6 The cumulative release rate curve of the pesticide at different temperatures is used to illustrate Example 6. Implementation

[0039] The reagents and their sources in the following examples are as follows: emamectin benzoate, Jiangsu Aijin Crop Science & Technology Group Co., Ltd.; cetyltrimethylammonium bromide, Shanghai Lingfeng Chemical Reagent Co., Ltd.; bis-[3-(triethoxysilyl)propyl]tetrasulfide, Sigma-Aldrich Trading Co., Ltd., St. Louis, Missouri, USA.

[0040] Examples 1-5

[0041] The following description uses Example 1 as an example.

[0042] Example

[0043] A glutathione-responsive organosilicon nanocarrier was prepared using the following steps:

[0044] (1) Preparation of mesoporous template agent:

[0045] 120 mL of ethanol and 300 mL of water were mixed to obtain an aqueous solution of the ethanol phase; then hexadecyltrimethylammonium bromide was dissolved in the aqueous solution to prepare an aqueous solution of the ethanol phase with a hexadecyltrimethylammonium bromide concentration of 1.5 g / L.

[0046] (2) Preparation of a mixed solution of mesoporous organosilicon nanocarrier precursor:

[0047] Mix 0.2 mL of bis-[3-(triethoxysilyl)propyl]tetrasulfide and 0.5 mL of tetraethyl orthosilicate to obtain a mixed solution of organosilicon nanocarrier precursor;

[0048] (3) The mixed solution from step (2) was added dropwise to the aqueous solution of the ethanol phase of hexadecyltrimethylammonium bromide obtained in step (1). The dropwise addition was controlled to be completed within 2 minutes. Then, the solution was heated in a water bath at 35°C, and the stirring speed was adjusted to 950 rpm. After stirring for 30 minutes, 4 mL of ammonia water was added, and the stirring speed was adjusted to 550 rpm. After stirring for 5 hours, the solution was centrifuged and the solid precipitate was transferred to a hydrothermal reactor and placed in a 150°C oven for 12 hours. The reaction solution was centrifuged again, the precipitate was washed with deionized water, and the solution was vacuum dried at 40°C to obtain a hollow mesoporous organosilicon nanocarrier. The amount of the mixed solution of the precursor added was 1.5 g / L.

[0049] Table 1. Concentrations of cetyltrimethylammonium bromide in Examples 1-5

[0050]

[0051] Examples 6-10:

[0052] The following description uses Example 6 as an example:

[0053] Example

[0054] A glutathione-responsive pesticide is prepared using the following steps:

[0055] Preparation of pesticide solution: Dissolve 5g of emamectin benzoate in 50mL of acetone solution and stir; disperse the organosilicon nanocarrier prepared in Example 1 in 120mL of water, transfer it to a hydrothermal reactor and place it in an oven at 150℃ for 12h; wash the centrifuged powder once with ethanol, transfer it to a mixed solution of 250mL of ethanol and 0.5mL of concentrated hydrochloric acid, and heat it in a water bath at 60℃ for 3h; finally, centrifuge the suspension, wash the centrifuged powder three times with ethanol, freeze-dry it and add it to the prepared pesticide solution, stir, centrifuge to obtain the solid powder, and obtain a hollow mesoporous organosilicon pesticide with glutathione responsiveness.

[0056] Table 2 shows the amount of organosilicon nanocarriers added in Examples 6-10.

[0057]

[0058]

[0059] Example 11:

[0060] A glutathione-responsive pesticide differs from Example 6 in that bis-[3-(triethoxysilyl)propyl]tetrasulfide and tetraethyl orthosilicate are mixed in a volume ratio of 1:1.

[0061] Example 12:

[0062] A glutathione-responsive pesticide differs from Example 6 in that bis-[3-(triethoxysilyl)propyl]tetrasulfide and tetraethyl orthosilicate are mixed in a volume ratio of 1:4.

[0063] Comparative Example 1:

[0064] Unetched organosilicon nanocarriers were used as blank samples.

[0065] Comparative Example 2:

[0066] A pesticide, which differs from Example 6 in that the mesoporous template agent is F127 template agent.

[0067] Comparative Example 3:

[0068] One pesticide differs from Example 6 in that the mesoporous organosilicon nanocarrier precursor uses a single tetraethyl orthosilicate.

[0069] Comparative Example 4:

[0070] One pesticide differs from Example 6 in that the mesoporous organosilicon nanocarrier precursor uses a single bis-[3-(triethoxysilane)propyl]tetrasulfide.

[0071] Performance testing methods:

[0072] (1) TEM image:

[0073] The morphology of the samples was examined using a transmission electron microscope (TEM, JEM-1400, NEC Corporation); (2) Glutathione responsiveness:

[0074] Weigh two 50 mg portions of the prepared hollow mesoporous organosilica nanocarrier loaded with emamectin benzoate, place them in dialysis bags, put them in two brown bottles, and add 100 mL of a mixed solution of ethanol and water (V). 乙醇 V 水=7:3 (one part with 0.1mM glutathione added, the other part without), put in a shaker, set the shaker temperature to 25℃, and at intervals, use a UV-Vis spectrophotometer (UV-2450, Shimadzu) to test the absorbance value of the solution, and calculate the drug concentration in the solution according to the standard curve;

[0075] (3) pH responsiveness:

[0076] First, three 50 mg portions of the prepared emamectin benzoate-loaded hollow mesoporous organosilica pesticide were weighed out and placed separately into dialysis bags. These bags were then placed in three brown bottles, and 100 mL of a mixture of ethanol and water (V) was added to each bottle. 乙醇 V 水 =7:3, pH 4.6, 6.2 and 9.0 respectively), put in a shaker, set the shaker temperature to 25℃, test the absorbance value of the solution at intervals, and calculate the drug concentration in the solution according to the standard curve;

[0077] (4) Temperature responsiveness:

[0078] First, weigh three 50 mg portions of the prepared hollow mesoporous organosilica pesticide loaded with emamectin benzoate and one 50 mg portion of emamectin benzoate technical grade pesticide, and place them separately into dialysis bags. Then, place these bags into four brown bottles and add 100 mL of a mixture of ethanol and water (V... 乙醇 V 水 =7:3), put it in a shaker, set the shaker temperature to 25℃, 35℃ and 45℃ respectively, the temperature of the emamectin benzoate technical material is also 25℃, test the absorbance value of the solution at intervals, and calculate the drug concentration in the solution according to the standard curve.

[0079] (5) Standard Curve

[0080] First, dissolve 5 mg of emamectin benzoate in a 100 mL mixture of ethanol and water (V 乙醇 V 水 =7:3), to obtain a stock solution of 50 mg / L. Take a series of drug stock solutions and dilute them with a mixed solution of ethanol and water (V 乙醇 V 水 =7:3), drug solutions of 5, 10, 15, 20, and 25 mg / L were obtained, and absorbance values ​​were measured. The results were recorded at 245 nm using a UV spectrophotometer, and a standard curve was plotted.

[0081] (6) Cumulative release rate:

[0082] First, the drug concentration in the solution is obtained according to (2), (3), and (4) in the performance testing method. The drug concentration is then substituted into equation (1) to obtain the cumulative release rate.

[0083]

[0084] Among them, C i C n These represent the concentrations of emamectin benzoate in the solution at that time; V i V represents the volume of solution taken out each time, which is 4 mL; V represents the total volume of buffer solution, which is 100 mL; and W represents the mass of emamectin benzoate loaded on the nanocarrier.

[0085] Analysis of test results:

[0086] Table 3. TEM images of Examples 1-8 and Comparative Example 1 under a transmission electron microscope.

[0087]

[0088] Combined with Examples 1-5, Comparative Example 1, and Table 3, Figs. 1-2 The test results show that the unetched organosilicon nanocarrier in Comparative Example 1 is a solid sphere, while organosilicon nanocarriers with hollow mesoporous structures were prepared in Examples 1-5. The test results from Examples 1-3 show that when the concentration of hexadecyltrimethylammonium bromide is between 1.5 and 2 g / L, the hollow structure of the nanocarrier is uniformly distributed and the size consistency is good; when the concentration of hexadecyltrimethylammonium bromide is less than 1.5 g / L or greater than 2 g / L, the hollow structure of the nanocarrier is uniformly distributed, but the size consistency deteriorates.

[0089] Combined with Examples 6-8 and Table 3 and Fig. 3 The test results show that the organosilicon nanopesticide loaded with emamectin benzoate has a uniformly distributed hollow structure and good dimensional consistency. Fig. 2 and Fig. 3 It can be seen that the structures of nanoparticles are not very different.

[0090] Table 4. Release of organosilicon nanopesticides loaded with emamectin benzoate in glutathione-containing and glutathione-free solutions.

[0091]

[0092] Based on Examples 6-10, Comparative Examples 2-4, and Table 4, it can be seen that the pesticides prepared in Examples 6-10 have thioether bonds in the shell of the organosilicon nanocarrier that can undergo redox reactions with glutathione in the body of pests. After contact with pests, the organosilicon shell is broken down more quickly, promoting the release of the active ingredient of the pesticide. After 30 hours of operation, the cumulative release rate can reach more than 72%, which is far greater than the release rate in the absence of glutathione. This indicates that the organosilicon nanopesticide loaded with emamectin benzoate of this application has glutathione responsiveness.

[0093] A comparison of the test results from Examples 6-8 and Examples 9-10 shows that the responsiveness to 0.1 mM glutathione is best when the amount of organosilicon nanocarrier added is between 0.5% and 1%. When the amount added is low, there are fewer thioether bonds in the shell of the nanocarrier, resulting in insufficient redox reaction with glutathione in the insect pest, which affects the release of the loaded emamectin benzoate. When the amount added is high, the organosilicon nanocarrier is not sufficiently dispersed in the pesticide, thus affecting the release of the loaded emamectin benzoate.

[0094] A comparison of the detection results from Examples 6-8 and Comparative Example 2 shows that when the template agent was replaced with F127, the release rate in 0.1 mM glutathione reached 66%, and the cumulative release rate in 0.1 mM glutathione decreased. This indicates that using hexadecyltrimethylammonium bromide as a template agent helps to promote the responsiveness to glutathione.

[0095] A comparison of the detection results from Examples 6-8 and Comparative Examples 3-4 shows that when the precursor of the mesoporous organosilicon nanocarrier is a single tetraethyl orthosilicate, the cumulative release rate of the nanocarrier in the presence of 0.1 mM glutathione is 62%. When the precursor is a single bis-[3-(triethoxysilyl)propyl]tetrasulfide, the cumulative release rate of the nanocarrier in the presence of 0.1 mM glutathione is 65%. This indicates that the precursor of this application, using bis-[3-(triethoxysilyl)propyl]tetrasulfide and tetraethyl orthosilicate, undergoes a hydrolysis reaction in an alkaline environment to synthesize an organosilicon with a thioether double bridge bond, which helps to promote the responsiveness of the nanocarrier to glutathione. 0044. In conjunction with Example 6 and Fig. 4 It can be seen that after 30 hours of drug administration, the release rate in the presence of 0.1 mM glutathione reached 74%, which is more than 20% higher than that without glutathione; after 60 hours of drug administration, the release rate in the presence of 0.1 mM glutathione reached 78%, while the release rate without glutathione remained at 60%; after 90 hours of drug administration, the release rate in the presence of 0.1 mM glutathione was 80%, while the release rate without glutathione was 60%, indicating that the sample of this application has a long-term drug release effect in the presence of 0.1 mM glutathione.

[0096] Table 5. Release of organosilicon nanopesticides loaded with emamectin benzoate at different pH values.

[0097]

[0098]

[0099] Based on Examples 6-8, Comparative Examples 2-4, and Table 5, it can be seen that the cumulative release rate of the organosilicon nanopesticide loaded with emamectin benzoate was approximately 35% at pH 4.6, about 45% at pH 9, and over 60% at pH 6.2 after 40 hours of application. This indicates that the cumulative release rate of emamectin benzoate was highest under neutral pH conditions within the same time period, demonstrating that the organosilicon nanopesticide loaded with emamectin benzoate exhibits pH responsiveness. 0046. Referring to Example 6 and... Fig. 5 It can be seen that after 60 hours of application, the cumulative release rate is about 40% at pH 4.6, about 55% at pH 9, and reaches 70% at pH 6.2. After 80 hours of application, the cumulative release rate is about 42% at pH 4.6, 56% at pH 9, and reaches about 73% at pH 6.2. This shows that the pesticide of this application has a higher cumulative release rate under neutral pH conditions as the release time increases.

[0100] Table 6. Release of organosilicon nanopesticides loaded with emamectin benzoate at different temperatures.

[0101]

[0102]

[0103] Based on Examples 6-8, Comparative Examples 2-4, and Table 6, it can be seen that the hollow mesoporous organosilicon nanopesticide loaded with emamectin benzoate has a cumulative release rate of 52% at 25°C, 62% at 35°C, and 65% at 45°C. This indicates that the release rate of emamectin benzoate increases with temperature, thus demonstrating that the organosilicon nanopesticide loaded with emamectin benzoate has a certain degree of sustained-release properties.

[0104] Refer to Example 6 and Fig. 6 It can be seen that after 60 hours of application, the cumulative release rate is 53% at 25℃, 63% at 35℃, and 65% at 45℃; after 80 hours of application, the cumulative release rate is 60% at 25℃, 68% at 35℃, and 70% at 45℃, indicating that the pesticide of this application has a long-term drug release effect at 45℃.

Claims

1. A pesticide comprising a glutathione-responsive organosilica nanocarrier, characterized in that, The method is prepared by the following steps: Prepare a pesticide solution; Add the nano-carrier to the pesticide solution, stir until uniform, and then centrifuge and dry to obtain the pesticide; The nano-carrier is prepared by the following steps: (1) Prepare a mesoporous template agent, which is an aqueous solution of cetyltrimethylammonium bromide in ethanol; (2) Prepare a mixed solution of mesoporous silicone nano-carrier precursors, which contains organosilanes with thioether bonds; (3) Add the mixed solution of step (2) dropwise to the aqueous solution of cetyltrimethylammonium bromide obtained in step (1), stir until uniform, adjust the system to basicity with ammonia, centrifuge to obtain solid precipitate, and then centrifuge, wash the precipitate with water, and dry to obtain the hollow mesoporous silicone nano-carrier; In step (1), the aqueous solution of cetyltrimethylammonium bromide in ethanol, wherein the aqueous solution of ethanol is a mixture of ethanol and water in a volume ratio of 1:(2-3); the concentration of cetyltrimethylammonium bromide is 1.5-2 g / L; In step (2), the mixed solution is a mixture of bis-[3-(triethoxysilyl)propyl]tetrasulfide and tetraethyl orthosilicate in a volume ratio of 1:(2-3); In step (3), the addition amount of the mixed solution of precursors is 1-1.5 g / L; In step (3), the dropwise addition is controlled to be completed within 2 minutes.

2. The pesticide containing glutathione-responsive organosilica nanocarriers according to claim 1, characterized in that: The drying treatment is vacuum drying at 40°C or freeze-drying at -80°C.

3. The pesticide containing glutathione-responsive organosilica nanocarriers according to claim 1, characterized in that: The effective component in the pesticide solution is one of abamectin and emamectin benzoate; the solvent is one of methanol, propanol, and dimethylamide; the mass percentage of the effective component in the pesticide solution is 2-10%.

4. The pesticide containing glutathione-responsive organosilica nanocarriers according to claim 2, characterized in that: The addition amount of glutathione-responsive silicone nano-carriers is 0.5-1% of the weight of the pesticide solution.

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