An ultraviolet protection biocontrolled release pesticide based on signal transduction and its preparation method

Abstract

The present invention relates to a signal-transmission-based ultraviolet protection biocontrolled release pesticide and a preparation method thereof. The preparation method includes: (1) removing free moisture from biomass and then heating it at a high temperature to obtain porous biochar; (2) impregnating the porous biochar obtained in step (1) with hydrogen peroxide to obtain hydrogen peroxide-modified biochar; (3) culturing the strain and then immobilizing it in the hydrogen peroxide-modified biochar obtained in step (2) by an adsorption method to obtain hydrogen peroxide-modified biochar loaded with the strain; (4) adding the hydrogen peroxide-modified biochar loaded with the strain obtained in step (3) into a framework material to obtain modified biochar with an all-enveloping framework loaded with the strain; (5) further complexing the modified biochar with an all-enveloping framework loaded with the strain obtained in step (4) with a modified cellulose-based ultraviolet protection film to obtain the signal-transmission-based ultraviolet protection biocontrolled release pesticide.

Description

Technical Field

[0001] The present invention relates to the technical field of biological pesticides, and particularly to an ultraviolet protection biological controlled-release pesticide based on signal transmission and a preparation method thereof. Background Art

[0002] Currently, due to the unreasonable use of chemical fertilizers and the expansion of industrial pollution, soil problems have become the key to restricting the increase in crop yields. How to improve soil quality and effectively repair polluted soil has become an urgent problem to be solved. Beauveria bassiana, as a new type of biological pesticide, can decompose and degrade pollutants, improve soil structure and quality, increase soil aeration and water retention, and promote plant growth. Therefore, Beauveria bassiana is widely used in soil remediation.

[0003] However, the use of Beauveria bassiana is largely restricted by the external environment: too high or too low temperature, pH, and strong ultraviolet irradiation will all affect the growth and repair ability of Beauveria bassiana. Among them, the effect of ultraviolet rays is particularly obvious. The short-wave ultraviolet rays (UV-C) in solar radiation have a strong bactericidal effect and can inhibit the metabolic activities of Beauveria bassiana. In order to protect the activity and proliferation ability of Beauveria bassiana in the soil, ultraviolet protection films have been developed to absorb strong external ultraviolet rays.

[0004] Traditional ultraviolet protection films can only play a protective role and cannot effectively achieve a controlled-release effect according to changes in the external environment. Therefore, some scholars have utilized the slow-release performance of natural polymer materials to achieve the integration of "protection + controlled release". However, the structure of this film is relatively thin and is easily broken in the soil, unable to effectively protect Beauveria bassiana and also unable to achieve the expected controlled-release effect. On this basis, some people have tried to construct a multi-level ultraviolet protection film to increase its mechanical strength, but the thickness of the film layer cannot be accurately measured. In a too thick film layer, only the surface protection film can play a role in absorbing ultraviolet rays, resulting in low protection efficiency and waste of raw materials. In addition, the bacteria cannot be effectively cross-linked and attached inside the film layer, the internal environment is unstable, and the biocompatibility is not high.

[0005] Therefore, there is an urgent need for an ultraviolet protection biological controlled-release pesticide with excellent protection effect, high ultraviolet protection efficiency, and stable internal environment to solve the above problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that the existing ultraviolet protection biological pesticides have poor protection effect, low protection efficiency, and it is difficult for the bacteria to grow normally. In view of the defects in the prior art, the present invention provides an ultraviolet protection biological controlled-release pesticide based on signal transmission and a preparation method thereof.

[0007] To solve the above technical problems, the present invention provides a preparation method of a UV - protection biocontrolled - release pesticide based on signal transmission, and the preparation method includes the following steps:

[0008] (1) Remove the free moisture from the biomass and then heat it at a high temperature to obtain porous biochar;

[0009] (2) Immerse the porous biochar obtained in step (1) with hydrogen peroxide to obtain hydrogen - peroxide - modified biochar;

[0010] (3) After culturing the strain, fix it in the hydrogen - peroxide - modified biochar obtained in step (2) by the adsorption method to obtain hydrogen - peroxide - modified biochar loaded with the strain;

[0011] (4) Add the hydrogen - peroxide - modified biochar loaded with the strain obtained in step (3) to the framework material to obtain modified biochar with an all - enveloping framework loaded with the strain;

[0012] (5) Further complex the modified biochar with an all - enveloping framework loaded with the strain obtained in step (4) with a modified cellulose - based UV - protection film to obtain the UV - protection biocontrolled - release pesticide based on signal transmission.

[0013] In the present invention, in step (1), the biomass is generally crushed, and the free moisture is removed by drying at 105 °C until the weight change rate is less than 0.1%. The high - temperature heating is carried out in a tube furnace.

[0014] In the present invention, the biomass can be rice straw, wood chips or rice husks, etc.

[0015] Preferably, the temperature of the high - temperature heating in step (1) is 400 - 800 °C, for example, it can be 400 °C, 500 °C, 600 °C, 700 °C or 800 °C, etc.

[0016] Preferably, the time of the high - temperature heating in step (1) is 1 - 2 h, for example, it can be 1 h, 1.5 h or 2 h, etc.

[0017] Preferably, the concentration of hydrogen peroxide in step (2) is 30 wt%.

[0018] Preferably, after the immersion in step (2), a drying process is also included to obtain the hydrogen - peroxide - modified biochar. In the present invention, during the immersion process, a stirrer can be used for stirring and oscillation. The temperature generally set for the drying process is 105 °C.

[0019] Preferably, the culture medium for culturing the strain in step (3) is a beef extract peptone culture medium.

[0020] Preferably, the pH value of the beef extract peptone culture medium is 5.0.

[0021] Preferably, the strain described in step (3) is Beauveria bassiana or Bacillus subtilis.

[0022] Preferably, the cultivation in step (3) is as follows: Cultivate on a shaker at a temperature of 27 °C and a rotation speed of 180 r / min for 7 days.

[0023] Preferably, the adsorption method in step (3) is as follows: Adsorb for 24 h on a shaker at a temperature of 27 °C and a rotation speed of 150 r / min.

[0024] In the present invention, the method of immobilizing the cells by adsorption is adopted, and the specific adsorption method is as follows: Add biochar into a glass centrifuge tube, and then sterilize it at 121 °C for 20 minutes. After the glass centrifuge tube is cooled, add the cell suspension into the tube. Subsequently, place the mixture of the cell suspension and biochar on a rotary shaker at 150 r / min and cultivate at 27 °C for 24 h until the cells are adsorbed on the surface and pores of the biochar. After separation, wash the biochar with deionized water multiple times to remove the unadsorbed cells, and obtain the H2O2-modified biochar loaded with cells.

[0025] Step (4) of the present invention is the key step of the present invention. This step envelopes the framework material onto the biochar, specifically as follows: (1) Dissolve UiO-66-PNIPAM and biochar in deionized water at a ratio of 1:1 - 1:3, and rotate at a speed of 150 r / min in a magnetic stirrer for 6 h to preliminarily cover the surface of the biochar with the framework material. (2) After mixing UiO-66 and gelatin evenly at a ratio of 1:4, dissolve the mixture in deionized water and use mechanical stirring (200 r / min) to make it evenly dispersed until a uniform colloid is formed. (3) Add the biochar preliminarily covered with the framework material obtained in step 1 into the UiO-66-PNIPAM / gelatin composite system obtained in step 2, and oscillate at a speed of 150 - 200 r / min for 8 - 12 h using a constant temperature oscillator, so that the framework material and gelatin fully envelope the surface of the biochar and show a uniform distribution. (4) Place the prepared biochar covered with UiO-66-PNIPAM / gelatin in a ventilated and dry environment, dry and solidify it, and finally obtain the modified biochar loaded with the fully enveloped framework strain.

[0026] Preferably, the framework material in step (4) is Uio-66-PNIPAM. Uio-66-NH2 is a metal-organic framework composed of zirconium ions (Zr 3+ ) and 2-aminoterephthalic acid (NH2-H2BDC), and can be applied to the field of soil remediation.

[0027] Preferably, the preparation method of Uio-66-PNIPAM is as follows: 2-aminoterephthalic acid and ZrCl4 are reacted in a solvent to obtain Uio-66-NH2 crystals, and then the Uio-66-NH2 crystals are immersed in a PNIPAM-NHS solution for reaction to obtain Uio-66-PNIPAM.

[0028] PNIPAM is poly(N-isopropylacrylamide). The PNIPAM-NHS solution is a solution of poly N-isopropylacrylamide-N-hydroxysuccinimide ester.

[0029] Preferably, the preparation method of the modified cellulose-based ultraviolet protection film in step (5) is as follows: 4,4'-dihydroxybenzophenone is reacted with toluene-2,4-diisocyanate to obtain an ultraviolet absorption crosslinking agent, and then the ultraviolet absorption crosslinking agent is added to a cellulose solution for reaction to obtain the modified cellulose-based ultraviolet protection film.

[0030] In the present invention, during the reaction of the ultraviolet absorption crosslinking agent and the cellulose solution, it is generally left standing for more than 6 h. At the same time, after drying, it is soaked in acetone for 2 h to obtain the modified cellulose-based ultraviolet protection film.

[0031] Preferably, the preparation method of the cellulose solution is as follows: microcrystalline cellulose is secondarily activated and then lithium chloride is added to obtain the cellulose solution.

[0032] Preferably, the solvent for the secondary activation is N,N-dimethylacetamide.

[0033] Preferably, the secondary activation is a process of heating reaction and cooling reaction.

[0034] Preferably, the temperature of the heating reaction is 100-200 °C, for example, it can be 100 °C, 150 °C, 180 °C or 200 °C, etc.

[0035] Preferably, the time of the heating reaction is 30-40 min, for example, it can be 30 min, 34 min, 38 min or 40 min, etc.

[0036] Preferably, the cooling reaction is to cool down to a temperature of 100-120 °C, for example, it can be 100 °C, 110 °C, 115 °C or 120 °C, etc.

[0037] Preferably, the time of the cooling reaction is 20-30 min, for example, it can be 20 min, 25 min or 30 min, etc.

[0038] The present invention also provides a signal transmission-based ultraviolet protection biocontrolled release pesticide prepared by the preparation method as described above.

[0039] The ultraviolet protection biocontrolled-release pesticide based on signal transmission provided by the present invention is structurally divided into outer, middle and inner layers. Among them, the outer layer is a modified cellulose-based ultraviolet protection film, which is used to receive exogenous ultraviolet stimulation and convert the optical signal into a thermal signal; the middle layer is Uio-66-PNIPAM, that is, the metal-organic framework Uio-66-NH2 modified by poly(N-isopropylacrylamide) (PNIPAM), which is used to generate an endogenous temperature response and convert the thermal signal into a biological signal; the inner layer is modified biochar loaded with Beauveria bassiana spores, which is used to directionally construct an optimal growth internal environment for the bacteria.

[0040] Compared with the existing controlled-release pesticides, the present invention realizes the efficient protection of ultraviolet rays through a three-layer structure, and at the same time can ensure the stability of the internal bacterial growth environment, achieving a controlled-release effect.

[0041] The outer layer is a modified cellulose-based ultraviolet protection film, which can effectively protect the biopesticide from ultraviolet rays during the release process. The cellulose membrane material is a biodegradable natural polymer material, which will not pollute the environment and has good biocompatibility and mechanical strength. Benzophenone and its derivatives are commonly used ultraviolet absorbers. By modifying the cellulose material with benzophenone groups, a film layer with both slow-release and ultraviolet protection capabilities can be designed for the biopesticide. At the same time, the ultraviolet protection film can also act as an external signal source, converting the optical signal of ultraviolet rays into a thermal signal and transmitting it inward, so that the biopesticide achieves precise controlled release.

[0042] The middle layer of the biopesticide is Uio-66-PNIPAM. Among them, Uio-66-NH2 is a metal-organic framework composed of zirconium ions (Zr 3+ ) and 2-aminoterephthalic acid (NH2-H2BDC), which can be applied to the field of soil remediation. Due to its large specific surface area and good pore structure, it can adsorb toxic pollutants in the soil through electrostatic action, chemical adsorption, etc., and the surface carboxyl and amino groups can react with organic molecules to degrade the organic pollutants adsorbed on the surface. In addition, the amino groups on the surface of Uio-66-NH2 have good biocompatibility, which can provide nutrients and a large number of attachment sites for the bacteria, and construct a stable endogenous environment. Through the synergistic effect with soil microorganisms, Uio-66-NH2 can promote the growth and metabolism of soil microorganisms, thereby accelerating the remediation of the soil. PNIPAM is a common temperature-sensitive material. When the temperature is lower than its lower critical solution temperature (LCST), PNIPAM has a high solubility, while when the temperature is higher than LCST, it will form a gel state. Uio-66-PNIPAM can well receive the temperature signal sent by the outer layer and generate an endogenous temperature response.

[0043] The innermost layer is H2O2-modified biochar loaded with biological bacteria. After being modified by H2O2, the biochar greatly enriches the content of surface acidic oxygen-containing functional groups, makes its physical and chemical properties more stable, and has stronger anti-biological decomposition ability. Due to the buffering effect of the biochar, its pH can be stably maintained in the acidic range of 4.0 - 5.5, which is consistent with the characteristics of biological bacteria. In addition, the H2O2 modification increases the specific surface area of the biochar, and the rich pore structure enables Beauveria bassiana to have sufficient primary reproduction sites for proliferation. The good coupling of carbon and bacteria can effectively reduce agricultural non-point source pollution and promote soil remediation, achieving the effect of "1 + 1 > 2".

[0044] The ultraviolet protection biological controlled-release pesticide based on signal transmission has the following signal transmission mechanism:

[0045] Since there are benzophenone groups in the outer modified cellulose-based ultraviolet protection film, under the stimulation of ultraviolet light, the carbonyl group is excited to generate free radicals. At this time, if there are primary amine substances in the environment, the free radicals will undergo a hydrogen abstraction reaction, the hydrogen of the primary amine substances is deprived, and the original free radicals will be transformed into new free radicals; if there is no hydrogen donor at this time, the benzophenone free radicals will eliminate free radicals under the action of oxygen. Through this series of transformations of benzophenone, the ultraviolet energy is transformed into heat energy and released and transmitted inward, thereby realizing the transformation of optical signal into thermal signal. When Uio-66-PNIPAM receives the thermal signal, it generates a temperature response: if the external ultraviolet radiation intensity is low, that is, in the case of receiving cold stress, the temperature-responsive polymer on the surface of Uio-66-PNIPAM will collapse from a three-dimensional spherical network structure to a two-dimensional linear network structure, thereby opening the channels of biological bacteria and increasing the release rate; if the external ultraviolet radiation intensity is high, that is, in the case of heat stress, the temperature-responsive polymer will entangle from a two-dimensional linear network structure into a three-dimensional spherical network structure, and biological bacteria cannot pass through the dense spherical network, so the release rate decreases. That is, Uio-66-PNIPAM realizes the transformation of thermal signal into biological signal.

[0046] Implementing the present invention has the following beneficial effects:

[0047] Compared with the existing controlled-release pesticides, the ultraviolet protection biological controlled-release pesticide based on signal transmission provided by the present invention realizes the ultraviolet protection effect through a three-layer structure, and at the same time can ensure the growth environment of internal bacteria, will not cause pollution to the environment, has good biocompatibility and mechanical strength. At the same time, the ultraviolet protection film of the present invention can also act as an external signal source, convert the optical signal of ultraviolet light into a thermal signal and transmit it inward, so that the biological pesticide achieves the effect of precise controlled release. Description of the Drawings

[0048] Figure 1It is the signal transmission mechanism diagram of the ultraviolet protection biocontrolled release pesticide based on signal transmission provided in Embodiment 1 of the present invention.

[0049] Figure 2 It is the schematic diagram of the ultraviolet protection system of the ultraviolet protection biocontrolled release pesticide based on signal transmission provided in Embodiment 1 of the present invention. Detailed implementation manners

[0050] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] Embodiment 1

[0052] (1) The biomass is crushed and screened, and then dried in an oven at 105 °C for 2 h until the weight change rate is less than 0.1% to completely remove the free moisture. The above biomass sample is placed in a tubular furnace, and nitrogen is introduced at a rate of 100 mL / min, and it is heated to 750 °C at a rate of 15 °C / min and held for 2 h to obtain porous biochar.

[0053] (2) The porous biochar is placed in a beaker and impregnated with 30 wt% H2O2 solution. It is placed on a magnetic stirrer and continuously oscillated at a rate of 150 r / min for 2 h, and then the residual H2O2 is washed away with deionized water. Finally, the sample is dried in an oven at 105 °C to obtain H2O2-modified biochar.

[0054] (3) Adjust the pH of the beef extract peptone liquid culture medium to 5.0, seal it and put it into an autoclave, set the sterilization temperature at 121 °C for 30 min, and inoculate Beauveria bassiana in the sterilized beef extract peptone liquid medium. Then the medium is placed in a constant temperature shaker, set the temperature at 27 °C and the rotation speed at 180 r / min, and culture for 7 days. The biochar is added to a glass centrifuge tube, and then sterilized at 121 °C for 20 min. After the glass centrifuge tube is cooled, the Beauveria bassiana suspension is added to the tube, and the mixture of it and the biochar is placed on a rotary shaker at 150 r / min and cultured at 27 °C for 24 h until Beauveria bassiana adsorbs to the surface and pores of the biochar. After separation, the biochar is washed repeatedly with deionized water to remove the unadsorbed bacteria to obtain H2O2-modified biochar loaded with Beauveria bassiana.

[0055] (4) 2-Aminoterephthalic acid and ZrCl4 were added to the reactor and thermally synthesized in N,N-dimethylformamide as the solvent. The solution was heated at 120 °C for 24 h, and then the Uio-66-NH2 crystals were collected by a centrifuge. The crystals were washed repeatedly with methanol to remove excess 2-aminoterephthalic acid and DMF. Subsequently, the crystals were immersed in a 0.1 M PNIPAM-NHS solution for a post-modification reaction, and then heated at 60 °C for 48 h to graft PNIPAM onto Uio-66-NH2, obtaining Uio-66-PNIPAM. Subsequently, the above-mentioned H2O2-modified biochar loaded with Beauveria bassiana was added to the prepared Uio-66-PNIPAM, and crosslinked sufficiently to obtain biochar loaded with Beauveria bassiana enveloped by a metal-organic framework.

[0056] (5) N,N-Dimethylacetamide was heated to 160 °C under nitrogen protection to remove the moisture therein. Subsequently, the pre-dried microcrystalline cellulose powder was activated at high temperature: the first activation temperature was 180 °C, the activation time was 35 min, and then the temperature was lowered to 120 °C for the second activation, and the activation time was 25 min. Subsequently, anhydrous lithium chloride was added at 120 °C and maintained for 50 min. After cooling at room temperature, a cellulose solution was obtained.

[0057] (6) 4,4'-Dihydroxybenzophenone was weighed and added to a beaker and dissolved with N,N-dimethylacetamide. Subsequently, toluene-2,4-diisocyanate was added and reacted at room temperature for 2 h to obtain an ultraviolet absorption crosslinking body. A certain amount of cellulose solution was added to the beaker, the ultraviolet absorption crosslinking body was added, and the mixture was allowed to stand and react at room temperature for 8 h to obtain a modified cellulose-based ultraviolet protection film solution.

[0058] (7) The biochar loaded with Beauveria bassiana enveloped by a metal-organic framework was added to the modified cellulose-based ultraviolet protection film solution, and crosslinked at a rate of 200 r / min in a magnetic stirrer for 6 h to allow the ultraviolet protection groups to be grafted sufficiently into the spatial structure of the metal-organic framework. After air-drying at room temperature and granulating, a signal-transmission-based ultraviolet protection biocontrolled-release pesticide was obtained. The signal-transmission mechanism diagram of the obtained biocontrolled-release pesticide is as Figure 1 shown, and the schematic diagram of the ultraviolet protection system is as Figure 2 shown.

[0059] Example 2

[0060] (1) The biomass was crushed and screened, and dried in an oven at 105 °C for 2 h until the weight change rate was less than 0.1% to completely remove free moisture. The above-mentioned biomass sample was placed in a tubular furnace, nitrogen was introduced at a rate of 100 mL / min, and the temperature was heated to 750 °C at a rate of 20 °C / min and held for 2 h to obtain porous biochar.

[0061] (2) Place the porous biochar in a beaker and impregnate it with a 30 wt% H2O2 solution. Place it in a magnetic stirrer and continuously oscillate it at a rate of 150 r / min for 2 h, and then wash away the residual H2O2 with deionized water. Finally, place the sample in an oven at 105 °C to dry and obtain H2O2-modified biochar.

[0062] (3) Adjust the pH of the nutrient broth liquid culture medium to 5.0, seal it and put it into an autoclave, set the sterilization temperature at 121 °C for 30 min, and inoculate Bacillus subtilis in the sterilized nutrient broth liquid culture medium. Then place the culture medium in a constant temperature shaker, set the temperature at 27 °C and the rotation speed at 180 r / min, and culture for 7 days. Add the biochar to a glass centrifuge tube, and then sterilize it at 121 °C for 20 min. After the glass centrifuge tube cools, add the Bacillus subtilis suspension to the tube, and place the mixture of it and the biochar on a rotary shaker at 150 r / min and culture at 27 °C for 24 h until Bacillus subtilis adsorbs onto the surface and pores of the biochar. After separation, wash the biochar with deionized water multiple times to remove the unadsorbed bacteria, and obtain H2O2-modified biochar loaded with Bacillus subtilis.

[0063] (4) Add 2-aminoterephthalic acid and ZrCl4 to the reactor and perform thermal synthesis in a solvent of N,N-dimethylformamide. The solution is heated at 120 °C for 24 h, and then Uio-66-NH2 crystals are collected by a centrifuge. Wash it with methanol multiple times to remove the excess 2-aminoterephthalic acid and DMF. Subsequently, immerse the crystals in a 0.1 M PNIPAM-NHS solution for a post-modification reaction, and then heat at 60 °C for 48 h to graft PNIPAM onto Uio-66-NH2 to obtain Uio-66-PNIPAM. Then add the above-mentioned H2O2-modified biochar loaded with Bacillus subtilis to the prepared Uio-66-PNIPAM, and fully crosslink to obtain biochar loaded with Bacillus subtilis enveloped by a metal-organic framework.

[0064] (5) Heat N,N-dimethylacetamide to 150 °C under nitrogen protection to remove the moisture in it. Subsequently, activate the pre-dried microcrystalline cellulose powder at 150 °C. The first activation time is 30 min, then cool it to 100 °C for the second activation, and the activation time is 20 min. Subsequently, add anhydrous lithium chloride at a temperature of 100 °C and keep it for 40 min. After cooling at room temperature, a cellulose solution is obtained.

[0065] (6) Weigh 4,4'-dihydroxybenzophenone and add it to a beaker, then dissolve it with dimethylacetamide. Subsequently, add toluene-2,4-diisocyanate and react at room temperature for 2 h to obtain an ultraviolet absorption crosslinking body. Take a certain amount of cellulose solution and add it to the beaker, add the ultraviolet absorption crosslinking body and let it stand and react at room temperature for 6 h. After drying, wash it with deionized water multiple times, and then soak it in acetone for 2 h to obtain a modified cellulose-based ultraviolet protection film.

[0066] (7) Complex the modified cellulose-based ultraviolet protection film with the metal-organic framework-encapsulated Bacillus subtilis biochar at room temperature to obtain a signal-transmission-based ultraviolet protection biocontrolled release pesticide.

[0067] Comparative Example 1

[0068] The difference between this comparative example and Example 1 is only that this comparative example does not include steps (5) and (6), and a biocontrolled release pesticide is prepared.

[0069] Comparative Example 2

[0070] The difference between this comparative example and Example 1 is only that this comparative example does not include step (4), and the rest of the preparation process is the same as that of Example 1, and a biocontrolled release pesticide is prepared.

[0071] Comparative Example 3

[0072] The difference between this comparative example and Example 1 is only that in this comparative example, the metal-organic framework material Uio-66-PNIPAM in step (4) is replaced with mesoporous silica, and a biocontrolled release pesticide is prepared.

[0073] Test the biocontrolled release pesticides provided in the above Examples 1-2 and Comparative Examples 1-3, and conduct a field control test. The specific process is as follows:

[0074] Randomly divide 7 plots of land with equal areas in the test field. Except for the blank group plot where no controlled release pesticide is set, each of the other plots is applied with each control scheme example, and the control group plot is applied with an equal amount of Beauveria bassiana control pesticide. Before the experiment and on the 7th, 10th, 14th, and 21st days after applying the medicine, use the "five-point sampling method" to measure the number of corn borers and perform normalization processing, and calculate the pest attenuation rate and control effect.

[0075] The specific calculation formulas are as follows:

[0076] Pest attenuation rate σ(%) = 100% * (N0 - N i ) / N0

[0077] N0: Relative pest quantity before applying the medicine

[0078] N i : Relative pest quantity on the i-th day after applying the medicine

[0079] Control efficiency η(%) = 100%*(σ i - σ 0i ) / (σ max - σ 0i )

[0080] σ i : Pest attenuation rate on the i-th day in the pesticide application area

[0081] σ 0i : Pest attenuation rate on the i-th day in the blank area

[0082] σ max : Maximum ideal attenuation rate, which is 100

[0083] Among them, a control group was set up. In the control group, the same amount of Beauveria bassiana control agent as that in the experimental group was applied to the land, and no control agent was added to the blank group. The specific experimental results are shown in Table 1 below.

[0084] Table 1

[0085]

[0086]

[0087] It can be seen from the data in Table 1 that:

[0088] (1) Example 1 and Example 2 have similar effects in the field experiment, and their control efficiency after pesticide application can reach more than 90%, showing the best ultraviolet protection performance and controlled release performance.

[0089] (2) There were short-term strong ultraviolet weather within 7 days after pesticide application and within 14 - 21 days after pesticide application. Since Comparative Example 1 lacked the modified cellulose-based ultraviolet protection film, the exogenous optical signal could not be transmitted into the controlled release system and converted into a thermal signal. Therefore, the control efficiency on the 7th day and 21st day after pesticide application decreased significantly compared with Example 1 and Example 2. When encountering weak ultraviolet weather within 7 - 14 days after pesticide application, due to the controlled release effect of the metal-organic framework and biochar, the control efficiency increased during this period and remained around 85%, and the gap between Comparative Example 1 and Example 1 and Example 2 was not obvious.

[0090] (3) Comparative Example 2 was provided with a modified cellulose-based ultraviolet protection film, which could convert optical signals into thermal signals and transfer them inward. It had good ultraviolet protection effect before the bacteria were released in the early stage, and its control efficiency was comparable to that of Example 1 and Example 2. However, due to the lack of a framework material modified with PNIPAM, it was unable to convert thermal signals into biological signals, and the wire mesh structure and spherical mesh structure could not achieve stress-induced transformation. Therefore, the signal transmission process was interrupted, and a large number of Beauveria bassiana were released. At this time, when encountering strong ultraviolet weather 14 - 21 days after the drug application, the ultraviolet protection film could not provide ultraviolet protection for the Beauveria bassiana outside the controlled-release drug. Therefore, the control efficiency of Comparative Example 2 decreased sharply during this stage.

[0091] (4) The control efficiency of Comparative Example 3 throughout the process was better than that of Comparative Example 1 and Comparative Example 2, showing relatively good ultraviolet protection performance and controlled-release performance, indicating that a complete signal transmission process plays an important role in improving the control efficiency. However, the biocompatibility of mesoporous silica decreased compared with the framework material, and its coupling effect with biochar was also not as good as that of the framework material. Therefore, the control efficiency could only be maintained at around 85%.

[0092] (5) By comparing Example 1 and Example 2 with Comparative Examples 1 - 3, it can be found that the difference in control efficiency caused by the interruption of signal transmission due to the lack of an ultraviolet protection film or framework material can reach 20%, while the difference in control efficiency caused by the replacement of the framework material is about 5%. This shows that in the controlled-release system, the dominant factor is the signal transmission process rather than the choice of the framework material.

[0093] (6) The control group lacked both the ultraviolet protection film and the bacterial growth environment constructed by the framework material and biochar. Therefore, both the controlled-release performance and the ultraviolet protection performance were much worse than those of Example 1 and Example 2.

[0094] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A preparation method of a bio-controlled release pesticide for ultraviolet protection based on signal transduction, characterized in that, The preparation method includes the following steps: (1) Remove the free moisture from the biomass and then heat it at a high temperature to obtain porous biochar; (2) Immerse the porous biochar obtained in step (1) with hydrogen peroxide to obtain hydrogen peroxide-modified biochar; (3) After culturing the strain, fix it in the hydrogen peroxide-modified biochar obtained in step (2) by the adsorption method to obtain hydrogen peroxide-modified biochar loaded with the strain; (4) Add the hydrogen peroxide-modified biochar loaded with the strain obtained in step (3) to the framework material Uio-66-PNIPAM to obtain modified biochar loaded with the strain encapsulated in the full envelope framework; (5) Further complex the modified biochar loaded with the strain encapsulated in the full envelope framework obtained in step (4) with a modified cellulose-based ultraviolet protection film to obtain the ultraviolet protection biocontrolled pesticide based on signal transduction; The specific steps for the framework material to envelope the biochar in step (4) are: Dissolve UiO-66-PNIPAM and biochar in deionized water at a ratio of 1:1 - 1:3, rotate at a speed of 150 r / min in a magnetic stirrer for 6 h to preliminarily cover the surface of the biochar with the framework material; After mixing UiO-66 and gelatin evenly at a ratio of 1:4, dissolve the mixture in deionized water and make it evenly dispersed by mechanical stirring (200 r / min) until a uniform colloid is formed; Add the biochar preliminarily covered with the framework material obtained in the previous step to the UiO-66-PNIPAM / gelatin composite system obtained in the previous step, and oscillate at a speed of 150 - 200 r / r / min for 8 - 12 h using a constant temperature oscillator to make the framework material and gelatin fully envelope the surface of the biochar and show a uniform distribution; Place the prepared biochar covered with UiO-66-PNIPAM / gelatin in a ventilated and dry environment, dry and cure it to finally obtain the modified biochar loaded with the strain encapsulated in the full envelope framework.

2. The preparation method according to claim 1, characterized in that, The temperature of the high-temperature heating in step (1) is 400 - 800 °C.

3. The preparation method according to claim 1, characterized in that, The time of the high-temperature heating in step (1) is 1 - 2 h.

4. The preparation method according to claim 1, wherein The concentration of hydrogen peroxide in step (2) is 30 wt%.

5. The preparation method according to claim 1, characterized in that, After the impregnation in step (2), a drying process is also included to obtain the hydrogen peroxide-modified biochar.

6. The preparation method according to claim 1, wherein, The culture medium for the strain in step (3) is a beef extract peptone culture medium.

7. The preparation method according to claim 6, characterized in that The pH value of the beef extract peptone culture medium is 5.

0.

8. The preparation method according to claim 1, characterized in that, The strain in step (3) is Beauveria bassiana or Bacillus subtilis.

9. The preparation method according to claim 1, characterized in that, The culture in step (3) is: Culture on a shaker at a temperature of 27 °C and a rotation speed of 180 r / min for 7 days.

10. The preparation method according to claim 1, characterized in that, The adsorption method in step (3) is: Adsorb at a temperature of 27 °C and a rotation speed of 150 r / min on a shaker for 24 h.

11. The preparation method according to claim 1, characterized in that, The preparation method of Uio-66-PNIPAM is: React 2-aminoterephthalic acid and ZrC14 in a solvent to obtain Uio-66-NH2 crystals, and then immerse the Uio-66-NH2 crystals into a PNIPAM-NHS solution for reaction to obtain Uio-66-PNIPAM.

12. The preparation method according to claim 1, characterized in that, The preparation method of the modified cellulose-based ultraviolet protection film described in step (5) is as follows: React 4,4'-dihydroxybenzophenone with toluene-2,4-diisocyanate to obtain an ultraviolet absorption crosslinking body, and then add the ultraviolet absorption crosslinking body to the cellulose solution to react to obtain the modified cellulose-based ultraviolet protection film.

13. The preparation method according to claim 12, wherein, The preparation method of the cellulose solution is as follows: After subjecting microcrystalline cellulose to secondary activation, add lithium chloride to obtain the cellulose solution.

14. The preparation method according to claim 13, characterized in that, The solvent for the secondary activation is N,N-dimethylacetamide.

15. The preparation method according to claim 13, wherein The secondary activation is a process that undergoes a heating reaction and a cooling reaction.

16. The preparation method according to claim 15, wherein, The temperature of the heating reaction is 100-200°C.

17. The preparation method according to claim 15, wherein, The time of the heating reaction is 30-40 min.

18. The preparation method according to claim 15, wherein The cooling reaction is to cool down to a temperature of 100-120°C.

19. The preparation method according to claim 15, characterized in that, The time of the cooling reaction is 20-30 min.

20. An ultraviolet protection biocontrolled release pesticide based on signal transduction prepared by the preparation method according to any one of claims 1-19.

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