Micro-fluidic chip, biopesticide microcapsule and preparation method of biopesticide microcapsule

Abstract

The invention discloses a micro-fluidic chip, a biopesticide microcapsule and a preparation method of the biopesticide microcapsule, the micro-fluidic chip comprises a cover plate, a first-stage shearing chip layer, an isolation layer, a second-stage shearing chip layer and a bottom plate which are arranged in sequence, and the first-stage shearing chip layer and the second-stage shearing chip layer are both provided with micro-channel units. Liquid phase inlet and outlet channels which are communicated with one another are arranged among the first-stage shearing chip layer, the isolating layer, the second-stage shearing chip layer and the bottom plate; and the liquid phase inlet and outlet channels are communicated with the micro-channel units on the chip. The biopesticide microcapsule prepared by the method is of a three-layer structure. Hydrophilic and hydrophobic modification of the two first-stage shearing chips in the chip is convenient, and the problems that a modification reagent flows and electrons cannot be locally modified can be avoided; and the device can adapt to W / O, O / W, W / O / W and O / W / O shearing systems, especially O1 / W / O2 and W1 / O / W2 systems, can realize secondary shearing, and is more suitable for pilot scale amplification and industrial equipment amplification.

Description

Technical Field

[0001] This invention relates to the field of biological sample pretreatment technology, specifically to a microfluidic chip, a biological pesticide microcapsule, and its preparation method. Background Technology

[0002] Compared with traditional pesticides, biopesticides can reduce or even avoid pesticide resistance and have less impact on the environment and human body. However, although biopesticides are environmentally friendly and have strong targeting, their active ingredients are usually more "delicate" than chemical pesticides and have the following weaknesses: (1) High environmental sensitivity, such as ultraviolet light: Many microbial insecticides (such as Bacillus thuringiensis Bt, viruses), plant-derived pesticides, and insect viruses are easily inactivated under sunlight. Plant-derived pesticides such as pyrethroids (broad-spectrum insecticides) and rotenone are prone to photodegradation and oxidation. Therefore, spraying is mainly carried out in the evening; (2) Short residual effect: Due to the above-mentioned environmental factors, their control effect is often difficult to last and frequent application is required; (3) Uncontrollable release; (4) Difficult formulation processing.

[0003] Microencapsulation technology is a crucial strategy for enhancing the performance of biopesticides and promoting their commercial application. Microencapsulation technology effectively addresses these challenges by creating a protective "shell." Currently, microfluidic chips are commonly used to prepare microencapsulated biopesticides. Microcapsule preparation is often divided into one-step and two-step methods. The one-step method involves biemulsion shearing occurring at the same location, forming microcapsules in a single step; the two-step method involves two shearing processes occurring on the same chip, but the generation of inner and outer droplets is spatially separated.

[0004] However, existing microfluidic chip designs all have some problems: (1) Low success rate: First-level shearing is relatively smooth, but second-level shearing is limited, mainly due to channel size and shearing port structure, requiring a lot of attempts and costing money and time.

[0005] (2) Modification is difficult: Currently, the main methods of hydrophilic-hydrophobic modification are reagent spraying, coating or use of isoelectronic devices. However, for devices that require segmented modification, the use of reagents will inevitably splash to other parts and cross-flow, and the local treatment of isoelectronic devices is difficult.

[0006] (3) It is a one-time structure and can only prepare microcapsules with a single structure, such as O / W / O type droplets. That is, a set of chips can only prepare one type of microsphere system and cannot prepare W / O / W type droplets, resulting in poor utilization.

[0007] Therefore, this patent application is filed. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a microfluidic chip, as well as a biopesticide microcapsule and a method for its preparation.

[0009] This invention is achieved using the following technical solution: The first objective of this invention is to provide a microfluidic chip, comprising a cover plate, a primary shearing chip layer, an isolation layer, a secondary shearing chip layer, and a base plate arranged sequentially. Microfluidic channels are provided on both the primary and secondary shearing chip layers. A liquid phase inlet / outlet channel is provided between the primary shearing chip layer, the isolation layer, the secondary shearing chip layer, and the base plate, and the liquid phase inlet / outlet channel is connected to the microfluidic channels on the chip.

[0010] As a preferred design, the liquid phase inlet / outlet channel includes: Main channel A, via A, via B, and main channel B are set on the first-level shear chip layer; Through-hole C is provided on the isolation layer; Main channel C, via D, and main channel D are set on the secondary shearing chip layer; The liquid outlet is located on the base plate; The main channel A, through hole A, and through hole B are all located on the side of the first-stage shearing chip layer near the cover plate, and the main channel B is located on the other side of the first-stage shearing chip layer. The main channel A, through hole A, and through hole B are all connected to the microchannel unit, and through hole A is connected to the main channel B. The through-hole C is connected to the through-hole B and to the microchannel unit on the secondary shear chip layer; The main channel C and the through hole D are both located on the side of the secondary shearing chip layer near the isolation layer. The main channel D is located on the other side of the secondary shearing chip layer. The main channel C and the through hole D are both connected to the microchannel unit on the secondary shearing chip layer. The through hole D is connected to the main channel D. The liquid outlet is connected to the main channel D.

[0011] As a preferred design, the cover plate, the primary shearing chip layer, the isolation layer, the secondary shearing chip layer, and the base plate are all square plates. The liquid phase inlet and outlet channel also includes inlet holes A, B, and C arranged side by side on the cover plate. Inlet hole A is connected to the main channel A, inlet hole B is connected to the main channel B, and inlet hole C is connected to the main channel C. At least one microchannel unit is provided on the primary shearing chip layer and the secondary shearing chip layer; And / or, the microfluidic unit includes a microfluidic tube with an "U"-shaped structure located in the middle and branch tubes on both sides connected to it. One branch tube is connected to the corresponding main channel, and the other branch tube is connected to the corresponding through hole.

[0012] As a preferred design, the cover plate, the primary shearing chip layer, the isolation layer, the secondary shearing chip layer, and the base plate are all circular plates. The liquid phase inlet and outlet channel further includes inlet holes A and B on the side of the first-stage shearing chip layer, and inlet hole C on the side of the second-stage shearing chip layer. The first-stage shearing chip layer is also provided with a diversion hole A communicating with inlet hole A and a diversion hole B communicating with inlet hole B. The second-stage shearing chip layer is also provided with a diversion hole C communicating with inlet hole C. Diversion hole A is communicating with main channel A, diversion hole B is communicating with main channel B, and diversion hole C is communicating with main channel C. At least one microchannel unit is provided on the primary shearing chip layer and the secondary shearing chip layer; And / or, the microfluidic unit includes a trapezoidal microfluidic tube in the middle and branch tubes on both sides connected to it. The branch tube on one side is connected to the corresponding main channel, and the branch tube on the other side is connected to the corresponding through hole. Each microfluidic unit is distributed in a ring array on the corresponding chip layer.

[0013] As a preferred design, the width and depth of each channel in the microchannel unit on the first-level shearing chip layer are 0.05~5mm, and the width and depth of each channel in the microchannel unit on the second-level shearing chip layer are 1~5 times the corresponding channel size on the first-level shearing chip layer. And / or, the diameter of each of the through holes is 0.05mm to 5mm; And / or, the width of each of the main channels is 0.05~300mm and the depth is 0.05~50mm.

[0014] The second objective of this invention is to provide a method for preparing biological pesticide microcapsules, which are prepared using a microfluidic chip as described in any of the preceding claims, and the reagents used in the preparation are O1 / W / O2 or W1 / O / W2 system reagents. And / or, the shearing mode of the microfluidic unit is flow focusing type; And / or, when the reagent is an O1 / W / O2 system, the flow rate of the O1 phase is 1~1000 mL / min, the flow rate of the W phase is 1~1000 mL / min, and the flow rate of the O2 phase is 1~1000 mL / min.

[0015] As a preferred design, the yield of microcapsules prepared using the microfluidic chip described in any of the above-mentioned methods is (0.5~1)*(0.8~1.5)*N g / min, where N is the number of microfluidic units, and the CV value of the obtained microcapsules is 30~40%.

[0016] A third objective of this invention is to provide a biological pesticide microcapsule, prepared using the method described above; The microcapsule comprises, from the inside out, a biopesticide core, an ultraviolet barrier layer, and an insect attractant layer. The O1 oil phase is used to prepare the biopesticide core and the ultraviolet barrier layer, the W aqueous phase is used to prepare the insect attractant layer, and the O2 oil phase is used to control the uniformity of the particle size of the insect attractant layer. And / or, the O1 oil phase reagent includes biopesticides and ultraviolet barrier substances, wherein the biopesticides include any one or a combination of two of plant-derived pesticides and animal-derived pesticides; The plant-derived pesticide is any one or a combination of several of the water-insoluble pyrethrin, rotenone, diflubenzuron, and azadirachtin. The animal-derived pesticide is either Nongmengte or Kasik; And / or, the ultraviolet barrier material is an oleophilic SiO2NPs or TiO2NPs, and the ultraviolet barrier layer accounts for 0~8%wt% of the O1 oil phase content.

[0017] As a preferred design, the aqueous phase reagent of W includes a forming agent and a pest attractant; The forming agent is any one or a combination of several of the following: sodium alginate, gelatin, pectin, gellan gum, chitosan, gum arabic, resin, beeswax, and white wax. The insect attractant is any one or a combination of several of the following: fatty acid derivatives and isoprene compounds. The fatty acid derivatives include acetates, alcohols or aldehydes with 1 to 4 carbon chains, and straight-chain alcohols; the isoprene compounds include monoterpenes or sesquiterpenes. And / or, the volume ratio of the forming agent to the insect attractant is 0.2 to 1.

[0018] As a preferred design, the O2 oil phase reagent includes one or a combination of several of vegetable oils, mineral oils, and surfactants; The vegetable oil is any one or more of sunflower seed oil and soybean oil; The mineral oil is one or more of dimethyl silicone oil, liquid paraffin, and white mineral oil; The surfactant is one or more of PGPR, EM90, and Span80; And / or, the surfactant has a mass content of 1-5%wt in the O2 oil phase reagent.

[0019] The advantages and beneficial effects of this invention compared to the prior art are: 1. The microfluidic chip provided by this invention can achieve a yield of up to 10 g / min. The two primary shearing chips used are easy to modify for hydrophilicity and hydrophobicity, which can avoid the problems of reagent migration and the inability to locally modify isoelectronics during segmented modification.

[0020] 2. The dual-emulsion chip structure provided by this invention is compatible with W / O, O / W, W / O / W, and O / W / O shearing systems, especially O1 / W / O2 and W1 / O / W2 systems. It can enter the next single-emulsion chip after the first-stage shearing to achieve secondary shearing, making it more suitable for pilot-scale amplification and industrial equipment amplification.

[0021] 3. Provide microencapsulation solutions for biopesticides that are not resistant to ultraviolet light, encapsulating them in wall materials to prolong the effectiveness and retention of biopesticides, avoid premature inactivation and decay, and provide other possibilities for spraying time, avoiding workers working at night.

[0022] 4. The biopesticide microcapsules provided in this embodiment of the invention comprise a biopesticide core, an ultraviolet barrier layer, and an insect attractant layer. The insect attractant layer can lure pests to approach through odor, and the pests achieve contact killing by ingesting the biopesticide core. Furthermore, the formed insect attractant layer can seal the gaps generated during the formation of the silica nanoparticle layer, preventing premature leakage of the biopesticide and rainwater infiltration. The ultraviolet barrier layer can shield against ultraviolet rays generated by sunlight, allowing the biopesticide to remain on the leaves, stems, or soil for a long time, increasing the insecticidal effect and reducing the frequency of spraying. This solves the technical problems of existing biopesticides, such as high environmental sensitivity, difficulty in achieving long-lasting control effects, and difficulties in formulation processing. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a side view of a microfluidic chip provided in Embodiment 1 of the present invention.

[0024] Figure 2 This is a top view of a microfluidic chip cover provided in Embodiment 1 of the present invention.

[0025] Figure 3 This is a top view of the first-stage shearing chip layer provided in Embodiment 1 of the present invention.

[0026] Figure 4This is a top view of the first-stage shearing chip layer provided in Embodiment 1 of the present invention.

[0027] Figure 5 This is a top view of the secondary shearing chip layer provided in Embodiment 1 of the present invention.

[0028] Figure 6 This is a top view of the secondary shearing chip layer provided in Embodiment 1 of the present invention.

[0029] Figure 7 This is a perspective view of a microfluidic chip provided in Embodiment 2 of the present invention.

[0030] Figure 8 This is a top view of the first-stage shearing chip layer provided in Embodiment 2 of the present invention.

[0031] Figure 9 This is a bottom view of the first-stage sheared chip layer provided in Example 2.

[0032] Figure 10 This is a top view of the isolation layer provided in Embodiment 2 of the present invention.

[0033] Figure 11 This is a top view of the secondary shearing chip layer provided in Embodiment 2 of the present invention.

[0034] Figure 12 This is a top view of the secondary shearing chip layer provided in Embodiment 2 of the present invention.

[0035] Figure 13 This is a top view of the base plate provided in Embodiment 2 of the present invention.

[0036] Figure 14 The images shown are electron micrographs (a) and physical images (b) of the microcapsules prepared in Example 3.

[0037] Figure 15 The image shows an electron microscope image of the beeswax microcapsules prepared in Example 8.

[0038] The markings and the components they represent in the attached diagram are as follows: 1-Cover plate, 2-Primary shearing chip layer, 3-Isolation layer, 4-Secondary shearing chip layer, 5-Base plate, 6-Microchannel unit, 7-Main channel A, 8-Through hole A, 9-Through hole B, 10-Main channel B, 11-Main channel C, 12-Through hole D, 13-Main channel D, 14-Microchannel, 15-Branch tube, 16-Inlet hole A, 17-Inlet hole B, 18-Inlet hole C, 19-Branch hole A, 20-Branch hole B, 21-Branch hole C, 22-Through hole C. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0040] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the invention.

[0041] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limiting the scope of protection of this invention. Example

[0043] A microfluidic chip includes a cover plate 1, a primary shearing chip layer 2, an isolation layer 3, a secondary shearing chip layer 4, and a base plate 5, which are assembled from top to bottom. The layers can be assembled together by screws or a pressing device.

[0044] like Figure 1 As shown, the cover plate 1 has the same width as the primary shearing chip layer 2, and the isolation layer 3, the secondary shearing chip layer 4, and the base plate 5 have the same width, which is greater than the width of the cover plate 1. The cover plate 1, the primary shearing chip layer 2, the isolation layer 3, the secondary shearing chip layer 4, and the base plate 5 all adopt a rectangular plate structure.

[0045] The primary shearing chip layer 2 is used for primary shearing, and the secondary shearing chip layer 4 is used for secondary shearing. Microfluidic units 6 are provided on both the primary and secondary shearing chip layers 2 and 4. The number of microfluidic units 6 is at least one, preferably two or more, and the microfluidic units 6 are arranged linearly and equally spaced on their respective shearing chips. A liquid phase inlet / outlet channel is provided between the primary shearing chip layer 2, the isolation layer 3, the secondary shearing chip layer 4, and the base plate 5. This liquid phase inlet / outlet channel is connected to the microfluidic units 6 on the chip. The liquid flows between the layers through the three-dimensional liquid flow channels formed between the layers, thereby achieving primary and secondary shearing and outflow to form microcapsules.

[0046] like Figures 2-6 As shown in this embodiment, the liquid phase inlet / outlet channel includes: Liquid inlet holes A 16, B 17, and C 18 are arranged side by side on cover plate 1; Main channel A7, through hole A8, through hole B9, and main channel B10 are set on the first-level shear chip layer 2; Through hole C is provided on the isolation layer 3; Main channel C11, through hole D12, and main channel D13 are set on the secondary shear chip layer 4; The liquid outlet is located on the base plate 5.

[0047] The main channel A7, through-hole A8, and through-hole B9 are all located on the side of the primary shearing chip layer 2 near the cover plate 1, while the main channel B10 is located on the other side of the primary shearing chip layer 2. The main channel A7, through-hole A8, and through-hole B9 are all connected to the microfluidic unit 6, and through-hole A8 is connected to the main channel B10. After entering the main channel A7, the liquid phase is distributed to each microfluidic unit 6. After undergoing primary shearing in each microfluidic unit 6, it flows out from each through-hole B9 to the intermediate isolation layer 3.

[0048] The via C on the isolation layer 3 is connected to via B 9 and the microchannel unit on the secondary shearing chip layer 4, thereby connecting the primary shearing chip layer 2 and the secondary shearing chip layer 4. Each microchannel unit 6 is provided with a corresponding via C.

[0049] Main channel C11 and via D12 are both located on the side of the secondary shearing chip layer 4 near the isolation layer 3, and main channel D13... On the other side of the secondary shearing chip layer 4, the main channel C11 and the through-hole D12 are both connected to the microfluidic unit 6 on the secondary shearing chip layer 4, and the through-hole D12 is connected to the main channel D13. The liquid phase entering the secondary shearing chip layer 4 first enters the main channel C11, and then is distributed to each microfluidic unit 6 for secondary shearing. After completion, it flows through the corresponding through-hole D12 into the main channel D13, then into the bottom plate 5, and finally out through the liquid outlet set on the bottom plate 5.

[0050] The liquid inlet A16 on the cover plate is connected to the main channel A7, the liquid inlet B17 is connected to the main channel B10, and the liquid inlet C18 is connected to the main channel C11.

[0051] Furthermore, in this embodiment, as Figure 3 , Figure 5 As shown, each microfluidic unit 6 includes a centrally located "U"-shaped microfluidic tube 14 and two side branch tubes 15 connected to the "U"-shaped microfluidic tube 14. One side branch tube 15 connects to the corresponding main channel, and the other side branch tube 15 connects to the corresponding through hole. For example, for the first-stage shearing chip layer 2, one side branch tube 15 connects to the main channel A 7, and the other side branch tube 15 connects to the through hole B 9; for the second-stage shearing chip layer 4, one side branch tube 15 connects to the main channel C 11, and the other side branch tube 15 connects to the through hole D 12.

[0052] In this invention, the microchannel unit 6 can also be configured as a straight line or an arc, such as an S-shape. In this embodiment, the primary shearing chip layer 2 can prepare O / W and W / O type droplets. The primary shearing chip layer 2, used in conjunction with the secondary shearing chip layer 4, can prepare O / W / O and W / O / W type droplets. Furthermore, O1 / W / O2 and W1 / O / W2 type droplets can also be prepared.

[0053] Furthermore, the width and depth of each channel in the microchannel unit 6 on the primary shearing chip layer 2 are 0.05~5mm, and the width and depth of each channel in the microchannel unit 6 on the secondary shearing chip layer 4 are 1~5 times the corresponding channel dimensions on the primary shearing chip layer 2. The diameter of each via is 0.05mm~5mm; the width of each main channel is 0.05~300mm, and the depth is 0.05~50mm.

[0054] Specifically, the diameter of through hole A8 is set to 1mm, the diameter of through hole B9 is 2mm, and the diameter of through hole D12 is 3mm.

[0055] The microchannel unit 6 in the primary shearing chip layer 2 has a size of 1mm × 1.5mm (width × depth); the size of each channel in the secondary shearing chip layer 4 is 1.5 times that of the primary shearing chip layer 2; the size of each main channel is 6mm × 6mm (width × depth). Both the primary shearing chip layer 2 and the secondary shearing chip layer 4 are made of aluminum alloy.

[0056] The specific process for preparing biopesticide microcapsules using the microfluidic chip in this embodiment is as follows: 1. Prepare aqueous and oil phase reagents and store them in reagent bottles with heating function; the reagents are O1 / W / O2 or W1 / O / W2 system reagents; 2. In this embodiment, the main channels of the microfluidic chip are used for the flow of O1 / W1, W / O, and O2 / W2, respectively, and the materials in the reagent bottle are transported into the above three main channels through the pipeline. That is, one liquid enters the main channel A7 through the liquid inlet A16, one liquid enters the main channel B10 through the liquid inlet B17, and one liquid enters the main channel C11 through the liquid inlet C18. 3. The three materials reach the microfluidic unit of the microfluidic chip and are sheared to form droplets; the shearing method of the microfluidic unit is flow focusing type; 4. After receiving, solidifying, cleaning and drying the droplets, microcapsules of biological pesticides with controllable particle size are obtained; the CV value of the microcapsules is 30~40%.

[0057] Example 2: A microfluidic chip includes, from top to bottom, a cover plate 1, a primary shearing chip layer 2, an isolation layer 3, a secondary shearing chip layer 4, and a base plate 5. The cover plate 2 and the isolation layer 3 can be made of transparent material. (See perspective view). Figure 7 .

[0058] Similarly, in this embodiment, as in Embodiment 1, such as... Figures 8-13 As shown, the primary shearing chip layer 2 also has a main channel A7, a through hole A8, a through hole B9, and a main channel B10. The isolation layer 3 is provided with a through hole C 22; A main channel C11, a through hole D12, and a main channel D13 are provided on the secondary shearing chip layer 4; A liquid outlet is provided on the base plate 5; Main channel A7, through hole A8, and through hole B9 are all located on the side of the first-stage shearing chip layer 2 near the cover plate 1, and main channel B10 is located on the other side of the first-stage shearing chip layer 2. Main channel A7, through hole A8, and through hole B9 are all connected to the microchannel unit 6, and through hole A8 is connected to main channel B10. Through-hole C22 is connected to through-hole B9 and to the microchannel unit on the secondary shear chip layer 4; The main channel C11 and the through hole D12 are both located on the side of the secondary shearing chip layer 4 near the isolation layer 3, and the main channel D13 is located on the other side of the secondary shearing chip layer 4. The main channel C11 and the through hole D12 are both connected to the microchannel unit 6 on the secondary shearing chip layer 4, and the through hole D12 is connected to the main channel D13. The liquid outlet is connected to the main channel D13.

[0059] The difference between this embodiment and Embodiment 1 is that: The cover plate 1, primary shearing chip layer 2, isolation layer 3, secondary shearing chip layer 4, and base plate 5 all adopt a circular plate structure. In this embodiment, the main channels A 7, B 10, C 11, and D 13 are all annular, and the center of each of the multiple microfluidic units 6 is a trapezoidal microfluidic tube 14, with branch tubes 15 on both sides of the trapezoidal microfluidic tube 14. In this embodiment, the multiple microfluidic units 6 are distributed in a ring array with equal spacing on the primary shearing chip layer 2 and the secondary shearing chip layer 4. Each microfluidic unit 6 corresponds to a through hole C 22, and in this embodiment, each through hole C 22 is also distributed in a ring array.

[0060] In this embodiment, liquid inlet holes A16 and B17 are arranged vertically on the side of the primary shearing chip layer 2, and liquid inlet hole C18 is provided on the side of the secondary shearing chip layer 4. The primary shearing chip layer 2 also has a diversion hole A19 communicating with liquid inlet hole A16 and a diversion hole B20 communicating with liquid inlet hole B17. The secondary shearing chip layer 4 also has a diversion hole C21 communicating with liquid inlet hole C18. Diversion holes A19, B20, and C21 are all located in the middle of the chip layer, with diversion hole A19 located on the top surface of the primary shearing chip layer 2 and diversion hole B20 located on the bottom surface of the primary shearing chip layer 2. Diversion hole A19 is connected to the main channel A7, diversion hole B20 is connected to the main channel B10, and diversion hole C21 is connected to the main channel C11.

[0061] In this embodiment, a liquid enters the diversion hole A19 through the inlet hole A16, then enters the main channel A7 through the diversion hole A19, and then flows into each microchannel unit. Another liquid enters the diversion hole B20 through the inlet hole B17, then enters the main channel B10 through the diversion hole B20, and then enters each microchannel unit through the through hole A8. A third liquid enters the diversion hole C21 through the inlet hole C18, then enters the main channel C11 through the diversion hole C21, and then enters each microchannel unit. After completing the primary and secondary shearing processes, the liquid flows through the corresponding through holes D12 into the main channel D13, then into the bottom plate 5, and finally exits through the outlet provided on the bottom plate 5.

[0062] In this embodiment, the design of the dimensions of each flow channel and the dimensions of each through hole of the microchannel unit are the same as in Embodiment 1, and will not be repeated here.

[0063] Example 3: The following is a method for preparing O1 / W / O2 system biopesticide microcapsules: Step 1: The oil phase reagent of O1 is a mixed solution of biological pesticide and ultraviolet barrier substance; the biological pesticide is a plant-derived pesticide, specifically water-insoluble pyrethrin; the ultraviolet barrier substance is lipophilic SiO2NPs, with SiO2NPs accounting for 6%wt of the O1 oil phase content. Pyrethrin and SiO2NPs are mixed and then magnetically stirred to disperse.

[0064] Step 2: The W aqueous phase is a mixture of a forming agent, an insect attractant, and purified water. The forming agent is sodium alginate containing 2%wt Ca-EDTA chelating agent. The volume ratio of the forming agent to the insect attractant is 1:0.8, that is, the content of the insect attractant in the mixture is 40%wt, and the content of sodium alginate in the mixture is 1%wt.

[0065] Step 3: The O2 oil phase is a mixture of white mineral oil and surfactant, with the surfactant being 5% wt EM90.

[0066] Step 4: Connect the three solutions to the chip respectively, check the airtightness, and then adjust the flow rate. The flow rate of the O1 phase is 50 mL / min; the flow rate of the W phase is 60 mL / min; and the flow rate of the O2 phase is 200 mL / min.

[0067] Step 5: The receiving phase is white mineral oil containing 3% (v / v) acetic acid.

[0068] After receiving and solidifying the microcapsules, clean them and place them at room temperature to dry for later use.

[0069] Reagents: Pyrethrum purchased online, 1.5% specification; SiO2NPs, oleophilic and hydrophobic type, particle size 20nm; fruit fly attractant purchased online.

[0070] The microcapsules obtained in this embodiment were subjected to the following tests: 1. Yield test: Record the time taken from the start of receiving to the end of receiving, and weigh the sample after cleaning and drying; 2. Morphology test: Microcapsules were photographed using an electron microscope, and CV values ​​were calculated; Result: The calculated yield for this batch was 10 g / min; Figure 14 The electron micrographs show that the core diameter of the prepared microcapsules is 1.13 mm (CV = 2.61%), and the outer diameter is 1.74 mm (CV = 4.23%). Figure 14The actual image shows that the kernel is white.

[0071] The principle of ultraviolet barrier layer formation is that the biopesticide oil solution and the oleophilic and hydrophobic silica nanoparticles form a Pickering emulsion. The hydrophobic particles of silica nanoparticles with a contact angle θ > 90° can form a water-in-oil (W / O) emulsion. Therefore, the silica nanoparticles migrate to the oil-water interface. During the static drying process at room temperature, the silica nanoparticles eventually form a shell that encapsulates the biopesticide.

[0072] The chips from Example 1 or Example 2 can be used for fabrication.

[0073] Example 4: The difference between Example 2 and Example 1 is as follows: The UV barrier material is oleophilic SiO2NPs, and the SiO2NPs account for 0%wt, 2%wt, 4%wt, 5%wt, and 8%wt of the O1 oil phase content. All other aspects are the same as in Example 2.

[0074] Test: The prepared microcapsules were exposed to ultraviolet light for 8 hours, and then the residual rate of pyrethrin in the microcapsules was determined by gas chromatography-mass spectrometry = residual amount / initial amount.

[0075] The results are shown in Table 1: Table 1

[0076] The results showed that, compared with microcapsules without added silica nanoparticles, microcapsules containing added silica nanoparticles had a higher pyrethrin residue rate, and the residue increased with increasing nanoparticle content. The ultraviolet barrier layer formed by the silica on the surface could shield against ultraviolet light irradiation and prevent decomposition. Furthermore, 5% wt silica nanoparticles exhibited good shielding effect, and this content was used in subsequent experiments.

[0077] Example 5: Based on Example 2, the difference lies in the W aqueous phase, where the volume ratios of the forming agent and the insect attractant are 1:1, 1:0.5, and 1:0.2, respectively, meaning the content of the insect attractant in the mixture is 50%, 25%, and 10%, respectively. All other aspects are the same as in Example 2.

[0078] Test: 5g of the prepared microcapsules were placed in a 10cm*10cm*5cm container and placed outdoors. After 24 hours, the number of fruit flies in each container was observed. The control group consisted of an equivalent amount of pyrethrum and fruit fly attractant directly added to the container. Each experiment had 3 parallel groups.

[0079] The results are shown in Table 2: Table 2

[0080] The results showed that although outdoor activities involve a lot of randomness, the higher the concentration of insect attractant, the better the insecticidal effect. The control group had fewer insects killed, possibly because pyrethroids decompose under ultraviolet light; although they attracted insects, they left due to the lack of insecticide. A 50% concentration of insect attractant was used in subsequent experiments.

[0081] Example 6: Based on Example 2, in step (1), the SiO2NPs content was set to 5%wt to prepare microcapsules; in step (2), the volume ratio of the forming agent to the insect attractant was 1:1.

[0082] Test: The prepared microcapsules were exposed to ultraviolet light for 0h, 2h, 8h, 12h, 18h, and 24h, and then the residual rate of pyrethrin in the microcapsules was determined by gas chromatography-mass spectrometry = residual amount / initial amount.

[0083] The results are shown in Table 3: Table 3

[0084] The results showed that as the irradiation time increased, the biopesticides encapsulated in microcapsules decomposed slowly, and the ultraviolet barrier function provided by the ultraviolet barrier layer may enable the biopesticides to remain on the leaves, stems or soil for a long time.

[0085] Example 7: Based on Example 2, the dimensions of the microchannel units 6 in the first-stage shearing chip layer 2 and the second-stage shearing chip layer 4 are modified as shown in Table 4 below.

[0086] Meanwhile, based on Example 2, the preparation of a biological pesticide microcapsule involves preparing the microcapsule with a SiO2NPs content of 5%wt in step (1) and a volume ratio of the forming agent to the insect attractant of 1:1 in step (2).

[0087] The prepared biopesticide microcapsules were examined using electron microscopy to determine the core, shell, and wall thickness. The results are shown in Table 4 below.

[0088] Meanwhile, the microcapsules prepared in experiments 4, 5, and 6 in Table 4 were soaked in water for 7 days, then removed, rinsed three times with water, and the residual rate of pyrethrin in the microcapsules was determined by gas chromatography-mass spectrometry (GC-MS) = residual amount / initial amount. The results are shown in Table 4.

[0089] Table 4

[0090] As shown in Table 4, by adjusting the size of the microchannel units of the two chips, microcapsules with different particle sizes and core sizes can be prepared, which can meet the requirements of pyrethroid's broad-spectrum insecticidal effect and be used for insects of different body lengths and lethal intake levels, such as aphids, leafhoppers, mosquitoes, flies, bedbugs, and cockroaches. Furthermore, by adjusting the ratio of the microchannel unit sizes of chip (D) to chip (B) (Experiments 4-6), microcapsules with different wall thicknesses can be prepared, thereby sealing the voids generated during the formation of the silica nanoparticle layer and preventing premature leakage of biopesticides and rainwater infiltration.

[0091] Example 8: A W1 / O / W2 system for preparing beeswax microspheres: W1: Vitamin C solution O: Beeswax W2: 3%wt PVA.

[0092] The above reagents were sequentially passed into the microfluidic chip as described in Example 1 for shearing to prepare beeswax microspheres. The results are as follows: Figure 15 As shown in the image.

[0093] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. 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 microfluidic chip, characterized in that, The chip includes a cover plate (1), a primary shearing chip layer (2), an isolation layer (3), a secondary shearing chip layer (4), and a base plate (5) arranged in sequence. The primary shearing chip layer (2) and the secondary shearing chip layer (4) are each provided with a microfluidic unit (6). The primary shearing chip layer (2), the isolation layer (3), the secondary shearing chip layer (4), and the base plate (5) are connected by a liquid phase inlet and outlet channel, which is connected to the microfluidic unit (6) on the chip.

2. A microfluidic chip according to claim 1, characterized in that, The liquid phase inlet / outlet channel includes: Main channel A (7), through hole A (8), through hole B (9), and main channel B (10) are set on the first-level shear chip layer (2). A through hole C (22) is provided on the isolation layer (3); The main channel C (11), through hole D (12), and main channel D (13) are set on the secondary shear chip layer (4). The liquid outlet is set on the base plate (5); The main channel A (7), through hole A (8), and through hole B (9) are all located on the side of the first-stage shearing chip layer (2) near the cover plate (1), and the main channel B (10) is located on the other side of the first-stage shearing chip layer (2). The main channel A (7), through hole A (8), and through hole B (9) are all connected to the microchannel unit (6), and the through hole A (8) is connected to the main channel B (10). The through hole C (22) is connected to the through hole B (9) and to the microchannel unit on the secondary shear chip layer (4); The main channel C (11) and the through hole D (12) are both located on the side of the secondary shearing chip layer (4) close to the isolation layer (3). The main channel D (13) is located on the other side of the secondary shearing chip layer (4). The main channel C (11) and the through hole D (12) are both connected to the microchannel unit (6) on the secondary shearing chip layer (4). The through hole D (12) is connected to the main channel D (13). The outlet is connected to the main channel D (13).

3. A microfluidic chip according to claim 2, characterized in that, The cover plate (1), the primary shearing chip layer (2), the isolation layer (3), the secondary shearing chip layer (4), and the base plate (5) are all square plates. The liquid phase inlet and outlet channels also include inlet holes A (16), B (17), and C (18) arranged in parallel on the cover plate (1). Inlet hole A (16) is connected to the main channel A (7), inlet hole B (17) is connected to the main channel B (10), and inlet hole C (18) is connected to the main channel C (11). At least one microchannel unit (6) is provided on the primary shearing chip layer (2) and the secondary shearing chip layer (4); And / or, the microfluidic unit (6) includes a microfluidic tube (14) with a "mouth"-shaped structure in the middle and branch tubes (15) on both sides connected thereto. One branch tube (15) is connected to the corresponding main channel, and the other branch tube (15) is connected to the corresponding through hole.

4. A microfluidic chip according to claim 2, characterized in that, The cover plate (1), the primary shearing chip layer (2), the isolation layer (3), the secondary shearing chip layer (4), and the base plate (5) are all circular plates. The liquid phase inlet and outlet channels also include inlet holes A (16) and B (17) on the side of the first-stage shearing chip layer (2) and inlet hole C (18) on the side of the second-stage shearing chip layer (4). The first-stage shearing chip layer (2) is also provided with a diversion hole A (19) communicating with the inlet hole A (16) and a diversion hole B (20) communicating with the inlet hole B (17). The second-stage shearing chip layer (4) is also provided with a diversion hole C (21) communicating with the inlet hole C (18). Diversion hole A (19) is communicating with the main channel A (7), diversion hole B (20) is communicating with the main channel B (10), and diversion hole C (21) is communicating with the main channel C (11). At least one microchannel unit (6) is provided on the primary shearing chip layer (2) and the secondary shearing chip layer (4); And / or, the microfluidic unit (6) includes a "trapezoidal" structure microfluidic tube (14) located in the middle and branch tubes (15) connected to it on both sides. One branch tube (15) is connected to the corresponding main channel, and the other branch tube (15) is connected to the corresponding through hole. Each microfluidic unit (6) is arranged in a ring array on the corresponding chip layer.

5. A microfluidic chip according to any one of claims 1 to 4, characterized in that, The width dimension of each channel in the microchannel unit (6) on the first-level shearing chip layer (2) is 0.05~5mm and the depth dimension is 0.05~5mm. The width dimension and depth dimension of each channel in the microchannel unit (6) on the second-level shearing chip layer (4) are 1~5 times the corresponding channel dimensions on the first-level shearing chip layer (2). And / or, the diameter of each of the through holes is 0.05mm to 5mm; And / or, the width of each of the main channels is 0.05~300mm and the depth is 0.05~50mm.

6. A method for preparing biological pesticide microcapsules, characterized in that, The microfluidic chip as described in any one of claims 1 to 5 is used to prepare the chip, and the reagents used in the preparation are O1 / W / O2 or W1 / O / W2 system reagents. And / or, the shearing mode of the microfluidic unit is flow focusing type; And / or, when the reagent is an O1 / W / O2 system, the flow rate of the O1 phase is 1~1000 mL / min, the flow rate of the W phase is 1~1000 mL / min, and the flow rate of the O2 phase is 1~1000 mL / min.

7. The method for preparing a biological pesticide microcapsule according to claim 6, characterized in that, The yield of microcapsules prepared using the microfluidic chip as described in any one of claims 1 to 5 is (0.5~1)*(0.8~1.5)*N g / min, where N is the number of microfluidic units (6), and the CV value of the obtained microcapsules is 30~40%.

8. A biopesticide microcapsule, characterized in that, Obtained by the preparation method described in claim 6 or 7; The microcapsule comprises, from the inside out, a biopesticide core, an ultraviolet barrier layer, and an insect attractant layer. The O1 oil phase is used to prepare the biopesticide core and the ultraviolet barrier layer, the W aqueous phase is used to prepare the insect attractant layer, and the O2 oil phase is used to control the uniformity of the particle size of the insect attractant layer. And / or, the O1 oil phase reagent includes biopesticides and ultraviolet barrier substances, wherein the biopesticides include any one or a combination of two of plant-derived pesticides and animal-derived pesticides; The plant-derived pesticide is any one or a combination of several of the water-insoluble pyrethrin, rotenone, diflubenzuron, and azadirachtin. The animal-derived pesticide is either Nongmengte or Kasik; And / or, the ultraviolet barrier material is an oleophilic SiO2 NPs or TiO2 NPs, and the ultraviolet barrier layer accounts for 0~8%wt% of the O1 oil phase content.

9. A biological pesticide microcapsule according to claim 8, characterized in that, W's aqueous phase reagents include forming agents and insect attractants; The forming agent is any one or a combination of several of the following: sodium alginate, gelatin, pectin, gellan gum, chitosan, gum arabic, resin, beeswax, and white wax. The insect attractant is any one or a combination of several of fatty acid derivatives and isoprene compounds. The fatty acid derivatives include acetates, alcohols or aldehydes with 1 to 4 carbon chains, and straight-chain alcohols; the isoprene compounds include monoterpenes or sesquiterpenes. And / or, the volume ratio of the forming agent to the insect attractant is 0.2 to 1.

10. A biological pesticide microcapsule according to claim 8, characterized in that, O2 oil phase reagents include one or more of vegetable oils, mineral oils, and surfactants; The vegetable oil is any one or more of sunflower seed oil and soybean oil; The mineral oil is one or more of dimethyl silicone oil, liquid paraffin, and white mineral oil; The surfactant is one or more of PGPR, EM90, and Span80; And / or, the surfactant has a mass content of 1-5%wt in the O2 oil phase reagent.

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