Temperature-responsive charge-controllable nano bactericide

Abstract

The invention discloses a temperature response type charge controllable nano bactericide. The average particle size range of the nano bactericide is 80-200nm, and the average Zeta potential range of the nano bactericide is-4.2 mV to 41.5 mV; the nano-bactericide is in a regular spherical shape and is composed of a positive polymer, a negative polymer and pyraclostrobin, surface charges of nano-particles are controlled by adjusting the proportion of the positive polymer to the negative polymer, and the deposition and uptake effects of the nano-particles on leaves are optimized through temperature response. Compared with the prior art, the pyraclostrobin has the advantages that the control effect on the botrytis cinerea can be up to 84% at most, meanwhile, the control effect on the botrytis cinerea can be improved to about 88% under temperature control and is nearly doubled compared with normal temperature, the application efficiency of the pyraclostrobin is remarkably improved, and the deposition uniformity of nano-particles and the uptake ability of plants are improved.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, and in particular to a temperature-responsive charge-controllable nano fungicide. Background Art

[0002] According to statistics, by the end of 2050, the world population will reach 9.9 billion, which will require a 60% increase in overall agricultural output relative to the 2005 level. While increasing crop yields, pesticides are widely used in crop protection, with global pesticide usage exceeding 4.6 million tons per year. However, due to various factors, the loss rate of active ingredients in traditional formulas is as high as 70-90%. The large-scale use of pesticides not only pollutes the terrestrial and aquatic environments, but also makes crops resistant to them. Therefore, reducing the amount of pesticides used and optimizing the formula to reduce the loss of active ingredients are important issues that need to be addressed in current and future agricultural development.

[0003] The low deposition of pesticide droplets on crop leaves and low leaf uptake are the main reasons for the high pesticide loss rate. Among the different solutions, the development of nanopesticide formulations is a promising way to solve these problems. Compared with traditional pesticide formulations, nanopesticides with large surface area and small size can enhance the adhesion and spreadability of pesticides on the surface of crop leaves, improve utilization, and also reduce the risk of environmental pollution. However, so far, most reported nanopesticides focus more on controlled release properties rather than the interaction between nanopesticides and leaves. The unique physicochemical properties of nanopesticides, such as surface charge, hydrophobicity, shape and size, may play an important role in their performance. Most traditional nanofungicides fail to fully utilize their surface charge characteristics to regulate the bactericidal effect. The charge characteristics of the microbial surface have a significant effect on the adsorption and action of nanofungicides. No fungicide optimized for different charge conditions has been developed in the prior art.

[0004] Therefore, in order to solve the above problems, the present invention provides a temperature-responsive charge-controllable nano fungicide; the nano fungicide of the present invention uses pyraclostrobin nanoparticles as an active ingredient, and the pyraclostrobin nanoparticles are formed by rapid self-assembly of two block copolymers with different charged properties and pyraclostrobin, and the surface charge of the nanoparticles is precisely controlled by adjusting the ratio of the two polymers, thereby maximizing the deposition and uptake of the nanoparticles on plant leaves, thereby achieving the best effect. Summary of the invention

[0005] The purpose of the present invention is to provide a temperature-responsive charge-controllable nano bactericide to fill the gap in current technology.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A temperature-responsive charge-controllable nano bactericide is in a regular spherical shape and is composed of a positive polymer, a negative polymer and pyraclostrobin. The positive polymer and the negative polymer are two polymers with different charges as carriers to encapsulate pyraclostrobin to prepare charge-controllable nanoparticles, wherein the ratio of the positive polymer to the negative polymer is 0.05-1.5, the average particle size of the nanoparticles is 80-200 nm, and the range of the surface charge is -4.2 mV-41.5 mV.

[0008] Preferably, the cationic polymer is selected from one of PDMAEMA-b-PCL or PEI-b-PCL, and the anionic polymer is selected from one of PNIPAM-b-PCL or PEG-b-PCL or PLGA-b-PCL.

[0009] Preferably, the nano bactericide controls the charge by temperature regulation, and the temperature regulation range is 25-55°C.

[0010] The method for preparing the temperature-responsive charge-controllable nano bactericide comprises the following steps:

[0011] S1, dissolving pyraclostrobin, a positive polymer and a negative polymer in tetrahydrofuran respectively as stream 1, and using ultrapure water as stream 2;

[0012] S2, injecting equal volumes of stream 1 and stream 2 into the mixer at the same time for mixing, with the injection flow rate being 30 mL / min, to obtain a nanoparticle mixed solution;

[0013] S3, placing the nanoparticle mixture obtained in step S2 in ultrapure water for 12-14 hours to remove organic solvents and impurities, thereby obtaining the temperature-responsive charge-controllable nano bactericide.

[0014] Preferably, the concentration of pyraclostrobin in the stream 1 is 0.1 mg / mL, and the total concentration of the positive polymer and the negative polymer is 0.1 mg / mL.

[0015] The present application also provides the use of the above-mentioned temperature-responsive charge-controllable nano fungicide for the prevention and control of plant gray mold and sterilization.

[0016] Working mechanism of the present invention:

[0017] The surface charge of the nanoparticles was regulated by adjusting the polymer ratio, and the average Zeta potential ranged from -4.2mV to 41.5mV; when the surface charge of the nanoparticles increased, their deposition amount on the leaves also increased accordingly, and the adhesion performance was significantly improved; at the same time, the absorption rate of the nanoparticles by the leaves showed a trend of first increasing and then decreasing with the increase of surface charge, and there was an optimal charge value to achieve the best absorption effect; then, the highly charged nanoparticles were reduced to an appropriate level by increasing the temperature to increase their absorption rate on the leaves, thereby achieving maximum adhesion and absorption effects.

[0018] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0019] 1. The temperature-responsive charge-controllable nano fungicide of the present invention has different deposition effects on leaves according to nanoparticles with different surface charges. By regulating the surface charge of nanoparticles, the adhesion amount and distribution uniformity of nanoparticles on leaves can be significantly improved, the adhesion ability of pesticide droplets on leaves can be effectively improved, and the loss of active ingredients of pesticides can be reduced;

[0020] 2. The temperature-responsive charge-controllable nano fungicide of the present invention has a therapeutic effect of up to 84% on tomato gray mold, and by adjusting the temperature, the therapeutic effect can be increased to about 88%, which is nearly doubled compared with normal temperature;

[0021] 3. The regulation of polymer ratio and temperature in the temperature-responsive charge-controllable nanofungicide of the present invention can flexibly control the properties of nanoparticles to adapt them to different application environments and crop requirements. This technology can be applied to different plant species and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, some of the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be made based on these drawings without paying any creative work.

[0023] Figure 1 are SEM images and TEM images of pyraclostrobin nanoparticles prepared in Example 1 of the present invention;

[0024] Figure 2 It is the Zeta potential diagram of the nano bactericide at different polymer ratios prepared in Example 1 of the present application;

[0025] Figure 3 This is a SEM image of the nano fungicide prepared in Example 1 of the present application on tomato leaves;

[0026] Figure 4 is a graph of the contact angle and liquid retention of the nano fungicide prepared in Example 1 of the present application on tomato leaves;

[0027] Figure 5 This is a fluorescence retention ratio diagram of the nano fungicide prepared in Example 2 of the present application on tomato leaves simulating resistance to rain erosion;

[0028] Figure 6 It is the fluorescence image and fluorescence uptake rate diagram of the nano fungicide prepared in Example 2 of the present application on tomato leaves;

[0029] Figure 7 Graph showing the inhibitory effect and antibacterial rate of the nano fungicide prepared in Example 1 of the present application on tomato gray mold fungi at different concentrations;

[0030] Figure 8 This is a Zeta potential diagram of the nano fungicide prepared in Example 1 of the present application at different temperatures;

[0031] Fig. 9 This is a graph of the fluorescence rate of the nano fungicide prepared in Example 2 of the present application on tomato leaves after being treated at different temperatures;

[0032] Fig.10 This is a graph showing the inhibition rate of the nano fungicide prepared in Example 1 of the present application against tomato gray mold fungi under different temperature treatments;

[0033] Fig.11 This is a diagram showing the therapeutic effect of the nano fungicide prepared in Example 1 of the present application on tomato leaves after being treated at different temperatures. DETAILED DESCRIPTION

[0034] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, a specific implementation scheme is now described in detail.

[0035] The present invention is further described below in conjunction with the embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to the different requirements of specific use, and the implementation conditions not indicated are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0036] Example 1

[0037] See attached Figure 1-4 , Attachment Figure 7-8 And attached Figure 10-11 This embodiment provides a temperature-responsive charge-controllable nano bactericide, and the preparation method of the nano bactericide comprises the following steps:

[0038] S1, pyraclostrobin (Pyr), positive polymer PDMAEMA-b-PCL and negative polymer PEG-b-PCL were dissolved in tetrahydrofuran, the concentration of pyraclostrobin was 0.1 mg / mL, the total concentration of polymer PDMAEMA-b-PCL and PEG-b-PCL was 0.1 mg / mL, the ratio of PDMAEMA-b-PCL to PEG-b-PCL was 0.05, 0.1, 0.5, 1, 1.5, respectively, as stream 1, and an equal amount of ultrapure water was used as stream 2;

[0039] S2, injecting equal volumes of stream 1 and stream 2 into a two-channel mixer at the same time for mixing, with an injection flow rate of 30 mL / min, to obtain a nanoparticle mixture;

[0040] S3, dialyzing the nanoparticle mixture obtained in step S2 in ultrapure water for 12 hours to remove organic solvents and impurities, thereby obtaining the temperature-responsive charge-controllable nano-bactericide;

[0041] The prepared nano-bactericide was subjected to electron microscopy analysis, and the results showed that the prepared nano-bactericide had good dispersibility. Figure 1 The above nano-bactericide was analyzed by Zetasizer, and the Zeta potential of the nano-bactericide is shown in the attached Figure 2 shown.

[0042] Example 2

[0043] See attached Figure 5-6 And attached Fig. 9 This embodiment provides a temperature-responsive charge-controllable nano bactericide, and the preparation method of the nano bactericide comprises the following steps:

[0044] S1, pyraclostrobin (Pyr), PDMAEMA-b-PCL, PEG-b-PCL and 5-fluorescein isothiocyanate were dissolved in tetrahydrofuran, the concentration of pyraclostrobin was 0.1 mg / mL, the concentration of 5-fluorescein isothiocyanate was 0.02 mg / mL, the total concentration of PDMAEMA-b-PCL and PEG-b-PCL was 0.1 mg / mL, the ratio of PDMAEMA-b-PCL to PEG-b-PCL was 0.05, 0.1, 0.5, 1, 1.5, respectively, as stream 1, and an equal amount of ultrapure water was used as stream 2;

[0045] S2, injecting equal volumes of stream 1 and stream 2 into a two-channel mixer at the same time for mixing, with an injection flow rate of 30 mL / min, to obtain a nanoparticle mixture;

[0046] S3. The nanoparticle mixture obtained in step S2 is dialyzed in ultrapure water for 12 hours to remove organic solvents and impurities, thereby obtaining a nano-bactericide loaded with 5-fluorescein isothiocyanate.

[0047] The application of the nano fungicide prepared in the above-mentioned Example 1 and Example 2 (including the different final products obtained by different ratios of the cationic polymer and the negative polymer in the process were respectively subjected to the following application tests):

[0048] ① Spray the nano fungicide prepared in Example 1 onto the washed and dried tomato leaves, dry them at room temperature (25°C), place the leaves on a platform at an angle of 60° to the ground, rinse them with 5 mL of ultrapure water to simulate natural rainwater flushing, dry them completely at room temperature after rinsing, and perform SEM electron microscopy analysis. Figure 3 As shown in the figure, it can be observed that the surface of the leaves without nanoparticles sprayed is relatively smooth, with some dust and no nanoparticles. After the leaves were sprayed with the nano fungicide with a polymer PDMAEMA-b-PCL / PEG-b-PCL of 0.05, a small amount of nanoparticles can be observed on the leaf surface. As the PDMAEMA-b-PCL / PEG-b-PCL ratio increases, the number of nanoparticles on the leaf surface also increases, indicating that as the polymer ratio increases, the interaction between the nanoparticles and the leaf surface gradually increases, causing more nanoparticles to be deposited on the leaf surface and not washed away by rain, thereby improving the leaf surface adhesion effect.

[0049] ② The nano fungicide prepared in Example 1 was dripped onto tomato leaves and the contact angle was measured. The results showed that the contact angle decreased with the increase of PDMAEMA-b-PCL / PEG-b-PCL. The tomato leaves were cut into pieces with an area of ​​4 cm 2 The square was immersed in the prepared solution for 10 seconds, taken out until no water dripped, weighed, and the liquid holding capacity was measured. The liquid holding capacity increased with the increase of PDMAEMA-b-PCL / PEG-b-PCL. As the surface charge of the prepared nano-bactericide nanoparticles increased, their wettability with the leaves was enhanced, making the nanoparticles easier to adsorb on the leaves. Figure 4 As shown;

[0050] ③ The nano fungicide prepared in Example 1 was placed in aqueous solutions at different temperatures for 24 hours, and then the Zeta potential was detected and analyzed using a Zetasizer. The results showed that as the temperature increased, the particle size of the nanoparticles continued to increase and the potential continued to decrease; when the polymer ratio was 1, the temperature increased to 40°C, and the surface charge of the nanoparticles could be reduced to 28mV; when the polymer ratio was 1, the temperature increased to 55°C, and the surface charge of the nanoparticles could be reduced to 30mV, which was similar to the potential of the nanoparticles with a polymer ratio of 0.5 at 25°C, as shown in the attached Figure 8 As shown;

[0051] ④ Taking tomato gray mold (Botrytis cinerea) as an indicator organism, the antibacterial properties of nanoparticles with different surface charges were explored. The nanofungicide prepared in Example 1 was placed in a water bath at 40°C and 55°C for 24 hours, and on the second day, 5 different concentrations (0.039, 0.156, 0.625, 2.5, 10 μg / ml) of PDA culture medium containing the treated nanofungicide were prepared under sterile conditions and poured into a sterile culture dish with a diameter of 90 mm and cooled to room temperature; a 5 mm plaque was taken from the edge of the gray mold mycelium activated and cultured for 48 hours, inverted and connected to the center of each culture medium, and a blank culture medium without drugs was used as a control group. Each treatment was repeated three times; the culture medium was placed in a mold incubator and cultured at 25±1°C for 72 hours, the diameter of the mycelium was measured by the cross method, and the average value was taken to calculate the antibacterial rate; the results are shown in the attached figure. Fig.10 As shown, it can be seen that with the increase of temperature, the antibacterial effects of polymer ratios of 1 and 1.5 are improved, which is consistent with the uptake results;

[0052] ⑤ Taking tomato gray mold (Botrytis cinerea) as an indicator organism, the antibacterial properties of nanoparticles with different surface charges were explored. Under sterile conditions, the nanofungicide prepared in Example 1 was prepared into a PDA culture medium containing the nanofungicide at 5 different concentrations (0.039, 0.156, 0.625, 2.5, and 10 μg / ml), poured into a sterile culture dish with a diameter of 90 mm and cooled to room temperature. A 5 mm plaque was removed from the edge of the gray mold mycelium that had been activated and cultured for 48 h, inverted and connected to the center of each culture medium, and a blank culture medium without drugs was used as a control group. Each treatment was repeated three times; the culture medium was placed in a mold incubator and cultured at 25±1°C for 72 h. The diameter of the mycelium was measured by the cross method, and the average value was taken to calculate the antibacterial rate. The results are shown in the attached figure. Figure 7 As shown, it can be seen that when the concentration is 0.039 μg / ml, the antibacterial rate when the polymer ratio is 0.5 is significantly higher than that of other groups, up to about 46%; its antibacterial rate first increases and then decreases with the increase of the surface charge of the nanoparticles;

[0053] The difference in the antibacterial rate of nanoparticles with different polymer ratios may be because they have different surface charges and different adsorption abilities on the surface of pathogens. Under the interaction of charges, the nanoparticles attracted to the surface of pathogens can destroy the integrity of the cell wall of pathogens and increase the permeability of the cell membrane, eventually leading to the death of pathogens. The surface of fungi generally carries a negative charge. As the proportion of positive polymers increases, the positive charge on the surface of nanoparticles gradually increases, and the attraction between them and pathogens increases, resulting in an increase in the antibacterial rate. However, as the positive charge continues to increase, the attraction between pathogens and nanoparticles will reach a saturated state, and the polarization state of the cell membrane may change, even causing repulsion, resulting in a decrease in the antibacterial rate.

[0054] The deposition of nanoparticles with different surface charges on leaves increased with the increase of charge, while the uptake of nanoparticles by leaves increased first and then decreased. In order to achieve the optimal conditions for leaf adsorption and uptake at the same time, the nanoparticles were regulated by temperature. The positive polymer PDMAEMA-b-PCL loaded with pyraclostrobin is a thermosensitive polymer that can change with changes in external temperature and has good biocompatibility, low cytotoxicity and degradability.

[0055] ⑥ Pick fresh ripe tomato leaves, clean the dust on the surface of the leaves, dry them naturally, and prepare the nano fungicide prepared in Example 1 into 10 mL of different pyraclostrobin solutions containing 0.1% TritonX-100. The concentration of pyraclostrobin is set to 10, 50, and 100 μg / mL. Pure water containing 0.1% TritonX-100 without adding the drug is used as a blank control. All treatments are repeated 3 times; use the needle of a sterile syringe to make a wound of the same size at the center of the dried leaves, connect the tomato gray mold pathogen cake that has been cultured for 72 hours, place it in a culture dish covered with moist gauze, and place it in a dark incubator at 25°C for 24 hours. Then, spray the leaves with the prepared different pyraclostrobin solutions, spray 1 mL on each leaf, and place them in incubators at 25°C, 40°C, and 55°C for 30 minutes, respectively. Regulate the surface charge of the nanoparticles to change the uptake of the leaves, and then place them in a dark incubator at 25°C for 3 days for further culture observation. Fig.11 As shown, at 25°C, the therapeutic effect of the leaves with a polymer ratio of 0.5 can reach up to 84%, and after temperature regulation, the therapeutic effect of the leaves with a polymer ratio of 1 at a concentration of 100 micrograms / ml increased from 49% at 25°C to 88% at 40°C, nearly doubling; the therapeutic effect of the leaves with a polymer ratio of 1.5 at a concentration of 100 micrograms / ml increased from 27% at 25°C to 77% at 55°C, a significant increase;

[0056] ⑦ The 5-fluorescein isothiocyanate-loaded nanofungicide prepared in Example 2 was sprayed on the washed and dried tomato leaves and dried at room temperature (25°C). After drying, the leaves were placed on a platform at 60° to the ground and rinsed with 5 mL of ultrapure water to evaluate the adhesion of the 5-fluorescein isothiocyanate-loaded nanofungicide; the change in fluorescence intensity before and after rinsing was observed with a fluorescence microscope, and the fluorescence intensity before and after rinsing was calculated with ImageJ. The fluorescence retention rate was calculated with the fluorescence before rinsing as a reference. The results showed that the fluorescence retention rate increased with the increase of the surface charge of the nanoparticles of the nanofungicide, which was consistent with the electron microscopy analysis, as shown in the attached Figure 5 As shown;

[0057] ⑧ The 5-fluorescein isothiocyanate loaded nano fungicide prepared in Example 2 was sprayed on the leaves of living tomato potted plants and placed in a dark environment for 24 hours. The leaves directly sprayed and the leaves next to them that were not sprayed were observed and analyzed using CLSM to evaluate the uptake of nano fungicide nanoparticles by the leaves. The results showed that the uptake rate of nanoparticles by the leaves showed a trend of first increasing and then decreasing with the increase of the surface charge of the nanoparticles. Figure 6 As shown;

[0058] ⑨ The 5-fluorescein isothiocyanate-loaded nano fungicide prepared in Example 2 was sprayed on the leaves of living tomato potted plants, placed in a dark environment for 24 hours, and then placed in 40°C and 55°C environments for 30 minutes to simulate a natural high temperature environment. The leaves directly sprayed and the leaves next to them that were not sprayed were observed and analyzed using CLSM to evaluate the uptake of nanoparticles by the leaves and compared with the uptake at 25°C. As shown in the attached figure Fig. 9 As shown, it can be seen that the uptake rate of leaves increased by 18% at 40°C and by 37% at 55°C. As the temperature increased, the surface charge of the nanoparticles decreased, and the uptake rate of the nanoparticles by the leaves increased. There is a certain correlation between the two. The decrease in the surface charge of the nanoparticles may reduce the electrostatic repulsion between the particles and the negative charges on the leaf surface, thereby increasing the adsorption and uptake of the particles. The increase in temperature reduces the charge density, making it easier for the nanoparticles to contact the leaf surface, resulting in an increase in the uptake rate. It may also be because the temperature change significantly increases the permeability of the membrane, allowing more particles to enter the cells.

[0059] Under lower surface charge conditions, the surface charge of the nanoparticles may not be sufficient to effectively adsorb to the leaf surface, making it difficult for the nanoparticles to exist stably on the leaf surface, resulting in a low uptake rate; as the surface charge increases, the electrostatic attraction between the nanoparticles and the leaf surface increases, prompting more nanoparticles to adhere to the leaves. At this time, the leaf uptake rate of the nanoparticles increases significantly; when the surface charge of the nanoparticles increases further, excessively strong electrostatic repulsion may occur, making it difficult for the nanoparticles to stabilize on the leaf surface, or forming a thicker charge layer on the leaf surface, thereby affecting the uptake rate. This may be due to charge saturation on the leaf surface or strong repulsion between the nanoparticles, resulting in a decrease in the uptake rate.

[0060] In summary, the temperature-responsive charge-controllable nano fungicide of the present invention has different deposition effects on leaves according to nanoparticles with different surface charges. By regulating the surface charge of the nanoparticles, the adhesion amount and distribution uniformity of the nanoparticles on the leaves can be significantly improved, the adhesion ability of the pesticide droplets on the leaves can be effectively improved, and the loss of active ingredients of the pesticide can be reduced; the temperature-responsive charge-controllable nano fungicide of the present invention has a therapeutic effect of up to 84% on tomato gray mold, and by adjusting the temperature, the therapeutic effect of low concentration can be increased by nearly doubled; the regulation of the polymer ratio and temperature in the temperature-responsive charge-controllable nano fungicide of the present invention can flexibly control the properties of the nanoparticles, so that it can adapt to different application environments and crop requirements. This technology can be applied to different plant species and has broad application prospects.

[0061] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A temperature-responsive charge-controllable nano-bactericide, characterized in that: The nano fungicide is in a regular spherical shape and is composed of a positive polymer, a negative polymer and pyraclostrobin. The positive polymer and the negative polymer, two polymers with different charges, are used as carriers to encapsulate pyraclostrobin to prepare charge-regulatable nanoparticles, wherein the ratio of the positive polymer to the negative polymer is 0.05-1.5, the average particle size of the nanoparticles is 80-200 nm, and the range of the surface charge is -4.2 mV-41.5 mV.

2. A temperature-responsive charge-controllable nano-bactericide as claimed in claim 1, characterized in that: The cationic polymer is selected from one of PDMAEMA-b-PCL and PEI-b-PCL, and the anionic polymer is selected from one of PNIPAM-b-PCL, PEG-b-PCL and PLGA-b-PCL.

3. A temperature-responsive charge-controllable nano bactericide according to claim 1, characterized in that: The nano bactericide controls the charge by temperature regulation, and the temperature regulation range is 25-55°C.

4. The method for preparing the temperature-responsive charge-controllable nano bactericide according to any one of claims 1 to 3, characterized in that: The steps include: S1, dissolving pyraclostrobin, a positive polymer and a negative polymer in tetrahydrofuran respectively as stream 1, and using ultrapure water as stream 2; S2, injecting equal volumes of stream 1 and stream 2 into the mixer at the same time for mixing, with the injection flow rate being 30 mL / min, to obtain a nanoparticle mixed solution; S3, placing the nanoparticle mixture obtained in step S2 in ultrapure water for 12-14 hours to remove organic solvents and impurities, thereby obtaining the temperature-responsive charge-controllable nano bactericide.

5. The method for preparing the temperature-responsive charge-controllable nano bactericide according to claim 4, characterized in that: The concentration of pyraclostrobin in the stream 1 was 0.1 mg / mL, and the total concentration of the positive polymer and the negative polymer was 0.1 mg / mL.

6. Application of the temperature-responsive charge-controllable nanofungicide prepared by the temperature-responsive charge-controllable nanofungicide according to any one of claims 1 to 3 or the method for preparing the temperature-responsive charge-controllable nanofungicide according to any one of claims 4 to 5 to the prevention and control of plant gray mold.

Images