Redox response type yeast microcapsule drug carrier as well as preparation method and application thereof

Abstract

The invention discloses a redox response type yeast microcapsule drug loading and a preparation method and application thereof, and belongs to the technical field of yeast microcapsule drug loading, and the preparation method comprises the following steps: dissolving a yeast microcapsule in an abamectin solution, carrying out pretreatment to obtain a precipitate, and carrying out freeze drying treatment on the precipitate to obtain a drug-loaded yeast microcapsule; putting the drug-loaded yeast microcapsule into a polyethyleneimine solution, and stirring to obtain a drug-loaded microcapsule solution adsorbed with polyethyleneimine; a photoinitiator and allicin are added into a drug-loaded microcapsule solution adsorbing polyethyleneimine for a polymerization reaction, the drug-loaded redox response type yeast microcapsule is obtained, and the technical problem that in the prior art, due to the fact that a pesticide preparation prepared through a preparation method cannot respond to environmental signals, the targeted transmission efficiency is low is solved.

Description

Technical Field

[0001] This invention belongs to the field of yeast microcapsule drug delivery technology, and relates to a redox-responsive yeast microcapsule drug delivery method and its preparation method and application. Background Technology

[0002] Traditional pesticide formulations often use spraying methods, which can lead to premature degradation, evaporation, surface runoff, or spray drift. As a result, only about 0.1% of them achieve the expected goal of controlling pests, while 99.9% diffuse into the environment, often failing to achieve the intended target.

[0003] From the perspective of technological limitations, traditional pesticide formulations suffer from a dual failure in terms of precision and stability. For example, non-target diffusion is uncontrollable: 1) Spray drift: Small droplets are easily affected by wind, temperature and humidity, drifting to non-target areas (near farmland, water sources, and residential areas); 2) Surface runoff: After rainfall or irrigation, the pesticide enters the deep soil or river channels with the water flow, expanding the pollution range; 3) Volatilization and photolysis: 30% to 90% of pesticides volatilize at high temperatures; ultraviolet light accelerates the decomposition of active ingredients, shortening the efficacy window period. From an environmental hazard perspective, traditional pesticide formulations also pose a problem of forming a pollution chain across the entire region, specifically including: 1) Water and soil pollution, groundwater infiltration: polar pesticides such as organophosphates can penetrate into groundwater aquifers (e.g., the detection rate of nitro pesticides in corn belts in the United States is >20%); eutrophication of water bodies: runoff pesticides (e.g., atrazine) disrupt the balance of aquatic microorganisms and induce algal blooms; 2) Non-target biological damage: extinction of beneficial insects: the mortality rate of pollinating insects (bees) and natural enemies (ladybugs, parasitic wasps) increases by 20% to 50%, disrupting ecological regulation; 3) Soil microecological collapse: nematicides cause a decrease of more than 60% in the abundance of soil nitrogen-fixing bacteria and actinomycetes, leading to soil fertility decline; 4) Bioaccumulation and food chain transmission: high-residue pesticides (e.g., DDT, chlorpyrifos): accumulate in the fatty tissues of fish and birds, with concentrations amplified a thousandfold. Therefore, developing new pesticide delivery technologies is crucial for delivering pesticides to their target locations to reduce pesticide loss and improve pesticide utilization efficiency. Stimulus-responsive controlled-release formulations offer a promising approach to improving pesticide utilization efficiency and reducing environmental risks.

[0004] Traditional pesticide formulations are prepared by mechanically dispersing the active ingredient and adjuvants, without forming chemical bonds, relying on interfacial physical adsorption to maintain system stability. For example, the preparation method for wettable powder pesticide formulations is: dry pulverization of the active ingredient → mixing with filler (kaolin) → adding a wetting agent (sodium lauryl sulfate) → air jet milling → sieving; the preparation method for emulsifiable concentrate formulations is: dissolving the active ingredient in an aromatic solvent → adding an emulsifier → high-speed shearing → filtration; the preparation method for suspension concentrate pesticide formulations is: wet grinding of the active ingredient (zirconia beads) → adding a dispersant (NNO) and a thickener (magnesium aluminum silicate) → homogenization emulsification (5000 rpm) → adjusting the pH to 6-8. However, pesticide formulations prepared by these methods suffer from problems due to the lack of stimulating responsive groups (such as -SS-, Schiff bases) in the physically mixed formulations. These groups cannot trigger release in the midgut of pests (reducing environment) or the infection zone of pathogens (acidic pH), resulting in an inability to respond to environmental signals and low targeted delivery efficiency.

[0005] Intelligent core-shell nanocarriers can release pesticides in response to pest-related microenvironmental stimuli and the physiological behavior of protected crops. This pesticide delivery system holds promise for minimizing the environmental risks of pesticides by controlling off-target losses. Yeast microcapsules with good biocompatibility can effectively load active ingredients, and their physicochemical properties can be easily customized through a multifunctional shell. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problem that pesticide formulations prepared by existing methods have low targeted delivery efficiency due to their inability to respond to environmental signals. Therefore, this invention provides a redox-responsive yeast microcapsule drug loading method and its application.

[0007] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a method for preparing redox-responsive yeast microcapsules for drug delivery, comprising the following steps: 1) Dissolve yeast microcapsules in an abamectin solution and pretreat to obtain a precipitate. Freeze-dry the precipitate to obtain drug-loaded yeast microcapsules. The volume concentration of the abamectin solution is (4~200) μg / mL. 2) The drug-loaded yeast microcapsules were placed in a polyethyleneimine solution and stirred to obtain a drug-loaded microcapsule solution adsorbed with polyethyleneimine; the volume concentration of the polyethyleneimine solution was (0.5~1) mg / mL. 3) Add the photoinitiator and allicin to the drug-loaded microcapsule solution that has been adsorbed with polyethyleneimine to carry out a polymerization reaction to obtain drug-loaded redox-responsive yeast microcapsules; the ratio of the amount of photoinitiator, allicin and drug-loaded microcapsule solution that has been adsorbed with polyethyleneimine is (4~6) mg: (50~70) mg: (15~50) mL.

[0008] Preferably, in the method for preparing redox-responsive yeast microcapsules according to claim 1, step 1) includes pretreatment including stirring at room temperature for 12-16 hours and centrifugation and washing 3-5 times.

[0009] Preferably, in the method for preparing redox-responsive yeast microcapsules according to claim 1, in step 2), the stirring conditions are stirring at room temperature for 10-25 minutes.

[0010] Preferably, in the method for preparing redox-responsive yeast microcapsules according to claim 1, step 3) involves polymerization under visible light for 1 to 1.5 hours.

[0011] Preferably, in the method for preparing redox-responsive yeast microcapsules according to claim 1, the method for obtaining the yeast microcapsules is as follows: Dry yeast powder was dispersed in NaOH solution and subjected to a first heating and centrifugation process to obtain a precipitate. The precipitate was then suspended in water, and the pH was adjusted to 4-5 with HCl before a second heating and centrifugation process. The precipitate was washed with isopropanol and acetone, respectively, and finally freeze-dried to obtain yeast microcapsules.

[0012] Preferably, in the method for preparing redox-responsive yeast microcapsules according to claim 5, the ratio of dry yeast powder, NaOH solution, water, isopropanol and acetone is (25~100) g: (0.25~1) L: (0.25~1) L: (50~200) mL: (50~200) mL.

[0013] Preferably, the preparation method of redox-responsive yeast microcapsules according to claim 5 is characterized in that the conditions for the first heating and centrifugation treatment include: heating temperature of 80~90℃, heating time of 0.75~1h; centrifugation time of 8~10min, and relative centrifugal force of (2000~2200)×g.

[0014] Preferably, the preparation method of redox-responsive yeast microcapsules according to claim 2 is characterized in that the conditions for the second heating and centrifugation treatment include: heating temperature of 55~60℃, heating time of 0.75~1h; centrifugation time of 10~15min, and relative centrifugal force of (2000~2200)×g.

[0015] The present invention also provides a redox-responsive yeast microcapsule drug-loaded product prepared by the above-described method, characterized in that the redox-responsive yeast microcapsule drug-loaded product has an elliptical morphology and a wrinkled surface; the average particle size is 2.96 μm ~ 5.36 μm.

[0016] This invention also provides the application of the redox-responsive yeast microcapsules described above in pesticide formulations.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention proposes a method for preparing redox-responsive yeast microcapsules for drug loading and release. In step 1), yeast microcapsules are treated with an abamectin solution at a volume concentration of (4~200) μg / mL to ensure efficient drug loading into the microcapsules. Pretreatment removes impurities, ensuring the integrity of the microcapsule structure and preventing drug leakage. After freeze-drying, the drug exists in a stable state within the microcapsules, laying the foundation for the subsequent responsive layer. In step 2), the drug-loaded microcapsules are treated with a polyethyleneimine (PEI) solution at a volume concentration of (0.5~1) mg / mL to form a polyelectrolyte layer. As a cationic polymer, PEI enhances the positive charge on the microcapsule surface, improves its adhesion to the negatively charged surfaces of pest and disease cells, and enhances targeted uptake efficiency. By controlling the volume concentration of polyethyleneimine, the adsorption rate of allicin on the microcapsule surface can be increased. In step 3), a photoinitiator and allicin are added to undergo a polymerization reaction to form a redox-responsive coating. Allicin, acting as a responsive unit, undergoes a redox reaction in reducing environments (such as high glutathione levels in pest and disease cells), leading to coating degradation or swelling and triggering abamectin release. A photoinitiator promotes polymerization under visible light, ensuring a uniform and stable coating. This step is crucial to this preparation method, enabling the microcapsules to "intelligently" respond to environmental signals and achieve targeted controlled drug release. In summary, through the allicin-PEI polymer layer, the microcapsules respond rapidly to redox signals, releasing the drug only at the target site, avoiding ineffective release in the field environment, and improving delivery efficiency.

[0018] Furthermore, stirring at room temperature for 12–16 hours and centrifuging and washing 3–5 times optimized the integrity and uniformity of drug loading. Prolonged stirring ensured that avermectin fully penetrated the pores of the yeast microcapsules, while centrifugation and washing removed unadsorbed drug impurities, reducing drug loss during preparation. This step ensured the uniformity and stability of the microcapsule structure, preventing drug leakage or defects in the response layer during preparation, thereby enabling more precise control of drug release in the response environment and avoiding inefficiencies caused by off-target release.

[0019] Furthermore, PEI adsorption was controlled by stirring at room temperature for 10–25 minutes to ensure that the PEI layer uniformly covered the surface of the drug-loaded microcapsules, avoiding damage or aggregation of the layered structure caused by excessive stirring. Short stirring time reduces energy consumption while maintaining the integrity of the PEI layer. The optimized PEI layer enhances the charge interaction between the microcapsules and pest cells, improves targeted adhesion, and provides a smooth surface for subsequent responsive polymerization, thereby enabling more efficient drug release upon redox triggering.

[0020] Furthermore, polymerization is carried out under visible light for 1 to 1.5 hours to ensure full activation of the photoinitiator and formation of a stable polymer coating. This time range avoids under-reaction (uneven coating) or over-reaction (excessive coating thickness affects responsiveness). This polymerization time precisely controls the coating thickness and permeability, resulting in uniform distribution of allicin responsive units, more sensitive response to redox signals, and improved timeliness of targeted drug release.

[0021] Furthermore, yeast cell impurities were removed by treatment with NaOH solution and HCl, forming a pure microcapsule carrier. Two heating and centrifugation processes optimized the microcapsule pore structure, improving drug loading capacity. The porous structure of the yeast microcapsules formed by NaOH and HCl treatment enhanced drug adsorption capacity, and their bio-based nature facilitated recognition and uptake by pests and diseases. Combined with the response layer, this enabled highly efficient targeted delivery.

[0022] Furthermore, the ratio of dry yeast powder, NaOH solution, water, isopropanol, and acetone is (25~100) g : (0.25~1) L : (0.25~1) L : (50~200) mL : (50~200) mL to ensure uniform yeast treatment and avoid excessive solvent causing microcapsule swelling or damage. This optimized ratio maintains the structural stability of the microcapsules, provides a reliable carrier basis for redox responses, reduces preparation variability, ensures batch-to-batch consistency, and thus improves the overall reliability of pesticide formulations.

[0023] Furthermore, heating at 80-90℃ for 0.75-1 hour, with a relative centrifugal force of (2000-2200)×g and a centrifugation time of 8-10 minutes, effectively removes cell wall impurities, forms a uniform porous structure, improves the mechanical strength and drug loading capacity of the microcapsules, and can also effectively separate yeast microcapsules, improving separation efficiency. High centrifugal force ensures the integrity of the microcapsule precipitation, avoids structural damage, and makes the response layer easier to form in subsequent steps, enhancing the stability of targeted release.

[0024] Furthermore, heating at 55–60°C for 0.75–1 h, centrifugation for 10–15 min, and a relative centrifugal force of (2000–2200) × g were used to gently treat and protect the bioactivity of the microcapsules. Centrifugation removed residual solvent and maintained the microcapsule morphology. Low-temperature treatment prevented yeast protein denaturation and maintained its targeted recognition ability; centrifugation conditions ensured microcapsule purification, reduced environmental interference, and optimized the performance of the response layer.

[0025] This invention also proposes a method for preparing redox-responsive yeast microcapsules. The resulting redox-responsive yeast microcapsules are elliptical in shape with a wrinkled surface and an average particle size of 2.96 μm to 5.36 μm. This structural feature increases the specific surface area, facilitating drug release and cellular uptake. The optimized particle size range improves dispersibility and retention on soil or plant surfaces, reducing non-targeted loss. The wrinkled surface allows redox signals (such as reducing molecules) to rapidly penetrate the coating, triggering drug release. The small size makes it easily absorbed by pests and diseases, responding to environmental changes within cells and improving targeted delivery efficiency.

[0026] This invention also proposes redox-responsive yeast microcapsules for direct application to pesticide formulations, leveraging the advantages of redox-responsive release. In the field environment, the microcapsules release the drug only at the site of pest and disease infection (reducing environment), reducing the impact on non-target organisms. Addressing the low delivery efficiency of existing pesticides, this product improves field targeting through an intelligent response mechanism. For example, in areas with high pest and disease incidence (such as high-glutathione environments at fungal infection sites), drug release is concentrated, bioavailability is improved, and the dosage is reduced. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a flowchart of the preparation of drug-loaded redox-responsive yeast microcapsules according to the present invention; Figure 2 This is a Fourier transform infrared image of the yeast microcapsules prepared according to the present invention; Figure 3 Here is a SEM image of the yeast microcapsules prepared according to this invention; Figure 4 Here is a SEM image of the drug-loaded redox-responsive yeast microcapsules prepared according to the present invention; Figure 5 This is a Zeta potential diagram of the drug-loaded redox-responsive yeast microcapsules prepared in this invention; Figure 6 This is a graph showing the release behavior of the drug-loaded redox-responsive yeast microcapsules prepared in Example 8 of this invention under different proportions of glutathione. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] The present invention will now be described in further detail with reference to the accompanying drawings: The present invention proposes a method for preparing redox-responsive yeast microcapsules for drug delivery, comprising the following steps: 1) Preparation of yeast microcapsules: 25-100 g of dry yeast powder was dispersed in 0.25-1 L of NaOH solution with a concentration of 1-1.5 mol / L. The solution was placed in a water bath at 80-90℃ for 0.75-1 h, centrifuged at 2000-2200 × g for 8-10 min, and the precipitate was resuspended in 0.25-1 L of water. The pH was adjusted to 4-5 with HCl, and the solution was incubated in a water bath at 55-60℃ for 0.75-1 h. After incubation, the solution was centrifuged at 2000-2200 × g for 10-15 min, washed 2-3 times with water, and then washed 2-4 times with 50-200 mL of isopropanol and 1-2 times with 50-200 mL of acetone. Finally, the precipitate was freeze-dried for 48 h to obtain yeast microcapsules. Figure 2 The Fourier infrared spectrum shown and Figure 3 The scanning electron microscope images shown indicate the successful preparation of yeast microcapsules; 2) Dissolve 0.25~1 g of the microcapsules from step 1) in an abamectin (AVM) solution with a volume concentration of (4~200 μg / mL), stir continuously at room temperature for 12~16 h, centrifuge and wash 3 times, centrifuge at 6000 rpm for 5 min to obtain the precipitate, and finally freeze-dry to obtain drug-loaded yeast microcapsules (microcapsule@AVM). 3) Place the drug-loaded microcapsules obtained in step 2) into (5~20) mL of polyethyleneimine (PEI) solution with a volume concentration of (0.5~1) mg / mL, and stir continuously at room temperature for 10~25 min to obtain a drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Figure 5 The zeta potential test results shown indicate that PEI was successfully adsorbed on the surface of the microcapsules; 4) Weigh 15-50 mL of the solution obtained in step 3) and add 4-6 mg of photoinitiator and 50-70 mg of allicin. Perform polymerization under visible light for 1-1.5 h to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM). Figure 5 As shown in the scanning electron microscope image, the successful preparation of drug-loaded redox-responsive yeast microcapsules was demonstrated.

[0034] This invention proposes a method for preparing redox-responsive yeast microcapsule drug delivery systems. Unlike traditional pesticide formulations, this method involves physically encapsulating the active ingredient into a functional carrier to respond to changes in the biotic / abiotic microenvironment and release it precisely and on demand. Specifically, this invention uses allicin as a raw material. Allicin is mainly derived from natural, green, and renewable resources such as garlic and onions. Due to its unique chemical structure, allicin is widely used in targeted drug delivery. First, in the natural environment, allicin can be completely degraded into carbon dioxide and water through the action of microorganisms, exhibiting good biodegradability and being environmentally friendly. As a green and low-carbon material, allicin helps reduce carbon emissions, aligning with global trends in carbon reduction and environmental protection. Second, by polymerizing a photoinitiator and polyethyleneimine (PEI) under visible light, a core-shell structure with a specific stimulus response is formed, which can improve insecticidal efficiency and enhance pesticide utilization. Compared with traditional pesticide formulations, the redox-responsive microcapsule material exhibits good stability and adhesion properties. By cross-linking allicin with yeast microcapsules using a photoinitiator and then applying visible light, allicin forms a unique responsive shell layer that "holds hands" (i.e., the breaking of carbon-carbon double bonds), successfully constructing a core-shell structure. This not only extends the lifespan of pesticides but also improves their application efficiency.

[0035] Furthermore, by controlling the adsorption concentration of avermectin (4~200) μg / mL, the drug loading rate can be increased.

[0036] Furthermore, by controlling the mass concentration of allicin in the solution (2.5~3.5) μg / mL, the shell thickness of the microcapsule response can be adjusted, thereby improving the drug's utilization efficiency.

[0037] The redox-responsive yeast microcapsule drug-carrying shell is prepared using allicin. (The shell is created by removing hydrogen atoms from the amino functional groups on the PEI surface under visible light irradiation. PEI free radicals initiate the graft polymerization of allicin (diallyl disulfide) on the yeast microcapsule surface, forming surface free radicals that initiate polymerization with monomers containing double bonds, forming a cross-linked shell on the template, thereby encapsulating and controlling the release of the drug. The shell is rich in SS bonds—a key component of the redox response mechanism.) The raw materials are widely available, biocompatible, and easily degradable. The response is achieved through the disulfide bonds (-SS-) contained in allicin (diallyl disulfide). The reducing environment of the diamondback moth's midgut (rich in glutathione, GSH) breaks the disulfide bonds, causing the carrier to disintegrate and release the encapsulated insecticide, thus achieving precise targeted release.

[0038] Example 1 Preparation of yeast microcapsules: 25g of dry yeast powder was dispersed in 0.25L of 1mol / L NaOH solution and placed in an 80℃ water bath for 0.75h. After centrifugation at 2000×g for 8min, the precipitate was suspended in 0.25L of water. The pH was adjusted to 4 with HCl and incubated in a 55℃ water bath for 0.75h. After incubation, the precipitate was centrifuged at 2000×g for 10min, washed twice with water, and washed twice with 50mL of isopropanol and once with 50mL of acetone. Finally, the precipitate was freeze-dried for 48h to obtain yeast microcapsules. 0.25 g of yeast microcapsules were dissolved in 5 mL of AVM solution with a concentration of 4 μg / mL. The solution was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The solution was stirred continuously at room temperature for 10 min to obtain drug-loaded microcapsule solution with PEI adsorption (PEI~microcapsule@AVM). Finally, 4 mg of photoinitiator and 50 mg of allicin were added to the above 15 mL drug-loaded microcapsule solution with PEI adsorption. The mass concentration of allicin in the solution was 2.5 μg / mL. The polymerization reaction was carried out under visible light irradiation for 1 h. After standing precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0039] Example 2 To prepare yeast microcapsules, 62g of dry yeast powder was dispersed in 0.63L of a 1.25mol / L NaOH solution and placed in a water bath at 85℃ for 0.88h. After centrifugation at 2100×g for 9min, the precipitate was resuspended in 0.63L of water. The pH was adjusted to 4.5 with HCl and incubated in a water bath at 57℃ for 0.88h. After centrifugation at 2100×g for 13min, the precipitate was washed twice with water, and then washed three times with 125mL of isopropanol and once with 125mL of acetone. Finally, the precipitate was freeze-dried for 48h to obtain yeast microcapsules. 0.5 g of yeast microcapsules were dissolved in 10 mL of AVM solution with a concentration of 8 μg / mL. The solution was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The solution was stirred continuously at room temperature for 10 min to obtain drug-loaded microcapsule solution with PEI adsorption (PEI~microcapsule@AVM). Finally, 4 mg of photoinitiator and 50 mg of allicin were added to the above 33 mL drug-loaded microcapsule solution with PEI adsorption. The mass concentration of allicin in the solution was 3 μg / mL. The solution was subjected to polymerization reaction under visible light irradiation for 1 h. After standing precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0040] Example 3 To prepare yeast microcapsules, 100g of dry yeast powder was dispersed in 1L of 1.5mol / L NaOH solution and placed in a 90℃ water bath for 1 hour. After centrifugation at 2200×g for 10 minutes, the precipitate was suspended in 1L of water. The pH was adjusted to 5 with HCl and incubated in a 60℃ water bath for 1 hour. After incubation, the precipitate was centrifuged at 2200×g for 15 minutes, washed three times with water, and then washed four times with 200mL isopropanol and twice with 200mL acetone. Finally, the precipitate was freeze-dried for 48 hours to obtain yeast microcapsules. 0.75 g of yeast microcapsules were dissolved in 15 mL of AVM solution with a concentration of 16 μg / mL. The solution was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The solution was stirred continuously at room temperature for 10 min to obtain drug-loaded microcapsule solution with PEI adsorption (PEI~microcapsule@AVM). Finally, 4 mg of photoinitiator and 50 mg of allicin were added to the above 50 mL drug-loaded microcapsule solution with PEI adsorption. The mass concentration of allicin in the solution was 3.5 μg / mL. The polymerization reaction was carried out under visible light irradiation for 1 h. After standing precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0041] Example 4 0.75 g of the yeast microcapsules prepared in Example 1 were dissolved in 15 mL of AVM solution with a concentration of 20 μg / mL. The mixture was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The mixture was stirred continuously at room temperature for 10 min to obtain drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 4 mg of photoinitiator and 50 mg of allicin were added to the above solution. The mass concentration of allicin in the solution was 2.5 μg / mL. The mixture was subjected to polymerization reaction under visible light for 1 h. After standing and precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0042] Example 5 0.75 g of the yeast microcapsules prepared in Example 1 were dissolved in 15 mL of AVM solution with a concentration of 40 μg / mL. The solution was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The solution was stirred continuously at room temperature for 10 min to obtain drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 4 mg of photoinitiator and 50 mg of allicin were added to the above 15 mL drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The polymerization reaction was carried out under visible light irradiation for 1 h. After standing precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0043] Example 6 1 g of the yeast microcapsules prepared in Example 1 were dissolved in 20 mL of AVM solution with a concentration of 80 μg / mL. The mixture was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The mixture was stirred continuously at room temperature for 10 min to obtain a drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 4 mg of photoinitiator and 50 mg of allicin were added to the above 15 mL drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The mixture was subjected to polymerization reaction under visible light irradiation for 1 h. After standing and precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0044] Example 7 1 g of the yeast microcapsules prepared in Example 1 were dissolved in 20 mL of AVM solution with a concentration of 120 μg / mL. The mixture was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The mixture was stirred continuously at room temperature for 10 min to obtain a drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 4 mg of photoinitiator and 50 mg of allicin were added to the above 15 mL of drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The mixture was subjected to polymerization reaction under visible light irradiation for 1 h. After standing and precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0045] Example 8 1 g of the yeast microcapsules prepared in Example 1 were dissolved in 20 mL of AVM solution with a concentration of 160 μg / mL. The mixture was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The mixture was stirred continuously at room temperature for 10 min to obtain a drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 4 mg of photoinitiator and 50 mg of allicin were added to the above 15 mL drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The mixture was subjected to polymerization reaction under visible light irradiation for 1 h. After standing and precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0046] Example 9 1 g of the yeast microcapsules prepared in Example 1 were dissolved in 20 mL of AVM solution with a concentration of 180 μg / mL. The solution was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The solution was stirred continuously at room temperature for 10 min to obtain drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 4 mg of photoinitiator and 50 mg of allicin were added to the above 15 mL drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The polymerization reaction was carried out under visible light irradiation for 1 h. After standing precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0047] Example 10 1 g of the yeast microcapsules prepared in Example 1 were dissolved in 20 mL of AVM solution with a concentration of 200 μg / mL. The mixture was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 20 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The mixture was stirred continuously at room temperature for 10 min to obtain a drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 6 mg of photoinitiator and 60 mg of allicin were added to the above 15 mL of drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The polymerization reaction was carried out under visible light irradiation for 1.5 h. After standing and precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0048] Example 11 1.2 g of the yeast microcapsules prepared in Example 1 were dissolved in 20 mL of AVM solution with a concentration of 200 μg / mL. The mixture was stirred continuously at room temperature for 12 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 25 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The mixture was stirred continuously at room temperature for 10 min to obtain a drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 4.5 mg of photoinitiator and 60 mg of allicin were added to the above 15 mL drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The polymerization reaction was carried out under visible light irradiation for 1.2 h. After standing and precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0049] Example 12 1.2 g of the yeast microcapsules prepared in Example 1 were dissolved in 20 mL of AVM solution with a concentration of 200 μg / mL. The mixture was stirred continuously at room temperature for 16 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 25 mL of polyethyleneimine (PEI) solution with a concentration of 0.5 mg / mL. The mixture was stirred continuously at room temperature for 10 min to obtain a drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 5.5 mg of photoinitiator and 60 mg of allicin were added to the above 15 mL of drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The mixture was subjected to polymerization reaction under visible light irradiation for 1.2 h. After standing and precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0050] Example 13 1.2 g of the yeast microcapsules prepared in Example 1 were dissolved in 20 mL of AVM solution with a concentration of 200 μg / mL. The mixture was stirred continuously at room temperature for 14 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 25 mL of polyethyleneimine (PEI) solution with a concentration of 0.75 mg / mL. The mixture was stirred continuously at room temperature for 20 min to obtain a drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 5.5 mg of photoinitiator and 60 mg of allicin were added to the above 15 mL of drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The polymerization reaction was carried out under visible light irradiation for 1.2 h. After standing and precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0051] Example 14 1.2 g of the yeast microcapsules prepared in Example 1 were dissolved in 20 mL of AVM solution with a concentration of 200 μg / mL. The mixture was stirred continuously at room temperature for 16 h. After centrifugation, the suspension was centrifuged at 6000 rpm for 5 min to obtain drug-loaded yeast microcapsules (microcapsule@AVM). Subsequently, the microcapsules were dispersed in 25 mL of polyethyleneimine (PEI) solution with a concentration of 1 mg / mL. The mixture was stirred continuously at room temperature for 25 min to obtain a drug-loaded microcapsule solution adsorbed with PEI (PEI~microcapsule@AVM). Finally, 5.5 mg of photoinitiator and 70 mg of allicin were added to the above 15 mL drug-loaded microcapsule solution adsorbed with PEI. The mass concentration of allicin in the solution was 2.5 μg / mL. The polymerization reaction was carried out under visible light irradiation for 1.2 h. After standing and precipitation, the supernatant was discarded to obtain drug-loaded redox-responsive yeast microcapsules (REDOXresponse~microcapsule@AVM).

[0052] like Figure 1 The preparation process of redox-responsive yeast microcapsules is shown in the figure. At the beginning, yeast cells are treated with chemical reagents such as acids and bases to form a porous microcapsule structure. The drug is loaded into the empty capsule through osmotic pressure. Then, the surface is modified by introducing amino groups from PEI through the negative charge of the surface. The hydroxyl groups on the photoinitiator steal hydrogen atoms from PEI to form free radicals. These free radicals graft allicin onto the surface of the microcapsule, initiating polymerization with monomers with double bonds. This gives the surface of the yeast microcapsule a responsive shell, thereby encapsulating and controlling the release of the drug.

[0053] like Figure 2 As shown, during the entire purification process, 1026 cm -1 The relative intensity of the polysaccharide main peak remained basically unchanged at 1700~1200 cm⁻¹, while the intensity at 1700~1200 cm⁻¹ remained relatively unchanged. -1 The relative intensity of the spectral bands in the regions (nucleic acids and proteins) gradually decreases, indicating that cytoplasmic content has been removed. 2900cm -1 The peak at 3400 cm⁻¹ represents the vibration of the -CH- group. -1 The peak at that point represents the stretching vibration of the -OH group, indicating the successful preparation of yeast microcapsules.

[0054] like Figure 3 As shown, the yeast microcapsules exhibit a well-defined elliptical morphology, with an average particle size of approximately 4.16 ± 1.2 μm. The microspheres show a wrinkled surface morphology, with pore sizes ranging from 10 to 100 nm and a pore volume of 0.15 cm³. 3 ·g -1This indicates that yeast microcapsules have abundant pores and a large specific surface area. This is mainly because yeast microcapsules are hollow microcapsules obtained from the cell wall of Saccharomyces cerevisiae by removing cytoplasmic contents. Such a structure is beneficial for loading AVMs into yeast microcapsules.

[0055] like Figure 4 As shown, the cross-linked shell of the allicin (diallyl disulfide) polymer resulted in larger microspheres with a diameter of approximately 4.8 ± 0.8 μm, a smooth surface, a pore size of 20 nm, and a smaller pore volume of 0.02 cm³. 3 .g -1 This makes it difficult for drug molecules to diffuse completely from the narrow openings and intricate channels.

[0056] like Figure 5 As shown, the zeta potential of free cells was -18 mV. After acid-base treatment, the potential of the yeast microcapsules was -13.5 mV. After stirring with PEI solution, the potential was +12.4 mV. Finally, the potential after the shell was formed was -5.5 mV. These positive and negative potential changes preliminarily prove the success of microcapsule preparation and the successful coating of PEI and allicin on the cell surface.

[0057] like Figure 6 As shown, the release behavior of AVM in the redox-responsive yeast microcapsules loaded with drug prepared in Example 8 was investigated at a temperature of 27°C and a pH of 7.0, under the action of different concentrations of glutathione. Figure 6 As shown, when the amount of glutathione added is less than 15%, the release process is stable and there is no explosive release. Moreover, the cumulative release rate increases with the increase of release time, and the cumulative release is higher (91.21%) when the mass percentage concentration of glutathione is 30%.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing redox-responsive yeast microcapsules for drug delivery, characterized in that, Includes the following steps: 1) Dissolve yeast microcapsules in an abamectin solution and pretreat to obtain a precipitate. Freeze-dry the precipitate to obtain drug-loaded yeast microcapsules. The volume concentration of the abamectin solution is (4~200) μg / mL. 2) The drug-loaded yeast microcapsules were placed in a polyethyleneimine solution and stirred to obtain a drug-loaded microcapsule solution adsorbed with polyethyleneimine; the volume concentration of the polyethyleneimine solution was (0.5~1) mg / mL. 3) Add the photoinitiator and allicin to the drug-loaded microcapsule solution that has been adsorbed with polyethyleneimine to carry out a polymerization reaction to obtain drug-loaded redox-responsive yeast microcapsules; the ratio of the amount of photoinitiator, allicin and drug-loaded microcapsule solution that has been adsorbed with polyethyleneimine is (4~6) mg: (50~70) mg: (15~50) mL.

2. The method for preparing redox-responsive yeast microcapsules according to claim 1, characterized in that, In step 1), the pretreatment includes stirring at room temperature for 12-16 hours and centrifuging and washing 3-5 times.

3. The method for preparing redox-responsive yeast microcapsules according to claim 1, characterized in that, In step 2), the stirring conditions are: stirring at room temperature for 10-25 minutes.

4. The method for preparing redox-responsive yeast microcapsules according to claim 1, characterized in that, In step 3), the polymerization reaction is carried out under visible light for 1 to 1.5 hours.

5. The method for preparing redox-responsive yeast microcapsules according to claim 1, characterized in that, In step 1), the method for obtaining the yeast microcapsules is as follows: Dry yeast powder was dispersed in NaOH solution and subjected to a first heating and centrifugation process to obtain a precipitate. The precipitate was then suspended in water, and the pH was adjusted to 4-5 with HCl before a second heating and centrifugation process. The precipitate was washed with isopropanol and acetone, respectively, and finally freeze-dried to obtain yeast microcapsules.

6. The method for preparing redox-responsive yeast microcapsules according to claim 5, characterized in that, The ratio of dry yeast powder, NaOH solution, water, isopropanol and acetone is (25~100) g : (0.25~1) L : (0.25~1) L : (50~200) mL : (50~200) mL.

7. The method for preparing redox-responsive yeast microcapsules according to claim 5, characterized in that, The conditions for the first heating and centrifugation treatment include: heating temperature of 80~90℃, heating time of 0.75~1h; centrifugation time of 8~10min, and relative centrifugal force of (2000~2200)×g.

8. The method for preparing redox-responsive yeast microcapsules according to claim 5, characterized in that, The conditions for the second heating and centrifugation treatment include: heating temperature of 55~60℃, heating time of 0.75~1h; centrifugation time of 10~15min, and relative centrifugal force of (2000~2200)×g.

9. A redox-responsive yeast microcapsule drug-loaded product prepared by the method for preparing redox-responsive yeast microcapsules according to any one of claims 1 to 8, characterized in that, The redox-responsive yeast microcapsules have an elliptical morphology with a wrinkled surface; the average particle size is 2.96 μm to 5.36 μm.

10. The application of the redox-responsive yeast microcapsule loading method according to claim 9 in pesticide formulations.

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