Method and device for preparing large-size microspheres with uniform particle size and regular shape

Abstract

The invention discloses a method and a device for preparing large-size microspheres with uniform particle size and regular morphology, and relates to the technical field of emulsion preparation, the method comprises the following steps: preparing a double-emulsion microsphere material containing an inner phase, an intermediate phase and an outer phase, the inner phase comprising an aqueous solution containing active components and a hydrophilic polymer surfactant, and the intermediate phase having a melting point of 50 DEG C lt; t fusion lt; an oil phase with the temperature of 85 DEG C and a lipophilic nonionic surfactant are adopted, an outer phase is a water phase solution, or a single emulsion microsphere material is prepared; then introducing the material into a micro-fluidic chip for molding, wherein the microsphere molding temperature is Tmelt + (10-15) DEG C; the formed microspheres are subjected to gradient cooling curing in a liquid outlet pipe or the formed microspheres are directly dropped into receiving liquid to be received and cured, and the temperature of the receiving liquid is (Tfu-30)-(Tfu-5) DEG C; according to the preparation method disclosed by the invention, the microspheres are formed stably, the probability that the microspheres receive demulsification and abnormal shapes is small, and the prepared large-size microspheres are uniform in particle size and regular in shape.

Description

Technical Field

[0001] The invention relates to the technical field of emulsion preparation, and in particular to a method and device for preparing large-sized microspheres with uniform particle size and regular shape. Background Art

[0002] Large-sized microspheres have a wide range of applications. In the biomedical field, they can be used as tissue repair scaffolds and large vessel embolization microspheres; in environmental monitoring, they can be used as pollutant adsorption carriers; and in the field of daily chemical products, they can be used to encapsulate active ingredients. The emulsion method for preparing large-sized microspheres suffers from poor process stability, resulting in uneven particle size and significant batch-to-batch variability. Microfluidics technology, which precisely controls the flow and dispersion of multiphase fluids within microchannels, offers unique advantages in the controlled preparation of emulsions.

[0003] However, the use of microfluidic technology to prepare large-sized microspheres presents significant technical challenges compared to small-sized microspheres. The main difficulties include the following aspects: 1. Interfacial tension limitation: Small-sized droplets are easily stabilized by interfacial tension, while large droplets are more susceptible to the characteristics of the material itself and inertial force or gravity during flow, breaking through the interfacial tension and causing rupture or aggregation; 2. Difficulty in multiphase flow regulation / fluid instability: The generation of large droplets requires precise control of the flow rate ratio of the continuous phase to the dispersed phase (such as capillary number and Weber number). A slightly higher flow rate can easily lead to turbulence and destroy laminar flow conditions; 3. Collection collision: Large microspheres are easily damaged due to collision or gravity sedimentation during the collection process; 4. Uneven curing: When the large-sized microspheres are cured internally, the outside may quickly cross-link and cure while the inside is not completely reacted, resulting in uneven structure (such as hollowness or collapse).

[0004] Due to the above technical difficulties, large-sized microspheres prepared using microfluidic technology have poor molding stability, resulting in problems such as uneven microsphere particle size, easy aggregation of microspheres, demulsification or the generation of irregular-shaped microspheres. Summary of the Invention

[0005] The present invention aims to solve the technical problems of poor molding stability in the preparation of large-sized microspheres using microfluidic technology in the prior art, resulting in uneven microsphere particle size, easy aggregation of microspheres, demulsification or the generation of irregular-shaped microspheres. The present invention aims to provide a method and device for preparing large-sized microspheres with uniform particle size and regular shape. During the preparation process, the microspheres are stably molded, the probability of demulsification and irregular shape of the microspheres is low, and the prepared large-sized microspheres have uniform particle size and regular shape.

[0006] The present invention is achieved through the following technical solutions.

[0007] The first object of the present invention is to provide a method for preparing large-sized microspheres with uniform particle size and regular shape, comprising: Material preparation: Double emulsion microsphere materials include: inner phase, middle phase and outer phase. The inner phase includes aqueous solution containing active ingredients and hydrophilic polymer surfactant. The middle phase includes a melting point of 50℃. <T 熔 <85℃ oil phase and lipophilic nonionic surfactant, the external phase is an aqueous solution; the single emulsion microsphere material includes: an internal phase and an external phase, the internal phase includes a melting point of 50℃ <T 熔 An oil phase, an active ingredient and a lipophilic nonionic surfactant at a temperature of <85°C, wherein the external phase is an aqueous solution; Microsphere forming: Each material is introduced into the corresponding liquid inlet of the microfluidic chip to form microspheres. The microsphere forming temperature is T 熔 + (10~15) ℃; Microsphere reception and curing: The formed microspheres are cured by gradient cooling in the liquid outlet pipe and then dropped into the receiving liquid or the formed microspheres are directly dropped into the receiving liquid for curing. The receiving liquid temperature is (T 熔 -30)~(T 熔 -5)℃.

[0008] The present invention adopts microfluidic technology to prepare millimeter-sized microspheres. By adding surfactants to both the inner phase and the middle phase, the wettability of the interface between the middle phase and the inner phase is effectively enhanced, and the stability of microsphere molding is improved. 熔 The oil phase with a temperature greater than 50℃ can not only ensure that the emulsion solidifies at 30℃~50℃, but also slow down its solidification speed. When receiving the solidification, two methods can be used. The first is to solidify in the liquid outlet pipe and set a gradient cooling method for solidification, which can reduce the stress accumulation generated during the microsphere solidification process and help maintain the good shape of the microspheres, thereby obtaining microspheres with regular shape and uniform particle size. The second method is to set the receiving liquid temperature to (T 熔 -30)~(T 熔 -5)℃, since the microspheres are at T 熔 + (10 ~ 15) ℃ molding, in (T 熔 -30)℃~(T 熔 The microspheres are cured at -5℃. The temperature gradient formed among the oil phase solidification temperature, microsphere forming temperature and curing temperature can not only ensure the curing and forming, but also appropriately slow down the curing speed, so that the oil phase of the microspheres can retain appropriate fluidity at the moment of entering the receiving liquid surface, thereby repairing the irregularities caused by the droplet falling and colliding. The subsequent slow curing can greatly improve the stability of the microsphere molding, and the obtained microspheres have more uniform particle size and more regular shape.

[0009] Among them, the active ingredient described in the present invention can be any biologically active substance, such as penicillin, epinephrine, dopamine, kojic acid, ferulic acid, coenzyme Q10s, green tea extract (EGCG), panthenol or tranexamic acid, etc., and its solubility concentration can be set as needed. For example, the concentration of the active ingredient can be arbitrarily adjusted from 0 to the maximum solubility of the active ingredient in the corresponding internal phase / intermediate phase, and the present invention does not impose any restrictions on this.

[0010] Furthermore, 50°C <T 熔 The oil phase below 85°C is composed of small molecule oils with a melting point below 45°C and solid waxes with a melting point above 60°C. The small molecule oils with a melting point below 45°C can enhance the wettability of the mesophase, improve the moisturizing effect, and simultaneously improve the phase uniformity and stability, and enhance the surface fineness and smoothness of the oil phase. The solid wax with a melting point above 60°C can enhance the hardness of the mesophase. When the two are mixed as the oil phase, they can improve the uniformity, stability, and surface smoothness of the microspheres.

[0011] Furthermore, the small molecule oil is any one or more of coconut oil, cocoa butter, susuba oil, shea butter, olive oil, palm oil, liquid paraffin, and lanolin; the solid wax is any one or more of beeswax, rice bran wax, carnauba wax, candelilla wax, microcrystalline wax, and solid paraffin. Melting point 50°C <T 熔 The oil phase <85°C can have a variety of combinations, as long as the melting point of the mixed system meets the requirements. Preferably, liquid paraffin is used as the small molecule oil and beeswax is used as the solid wax. More preferably, the mass ratio of liquid paraffin and beeswax is 6:4, and the melting point of the mixed system is 60°C.

[0012] Furthermore, the microsphere molding temperature is 55°C to 95°C. The microsphere molding temperature is determined by the melting point of the oil phase T 熔 Adjustment is made. For example, when the mass ratio of liquid paraffin and beeswax is 6:4 and the melting point of the mixed system is 60°C, the microsphere molding temperature is 75°C.

[0013] Furthermore, in the double emulsion microsphere material, the mass concentration of the hydrophilic polymer surfactant in the internal phase is 0.2% to 10%, for example, the mass concentration is 0.2%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, preferably the mass concentration is 5%, the mass concentration of the lipophilic nonionic surfactant in the middle phase is 1% to 4%, for example, the mass concentration is 1%, 2%, 3% or 4%, preferably the lipophilic nonionic surfactant content is 3%; in the single emulsion microsphere material, the mass concentration of the lipophilic nonionic surfactant in the internal phase is 1% to 4%, for example, the mass concentration is 1%, 2%, 3% or 4%, preferably the lipophilic nonionic surfactant content is 3%.

[0014] Furthermore, the hydrophilic polymer surfactant in the inner phase of the double emulsion microsphere material is any one or more of polyvinyl alcohol, sodium alginate, chitosan, and polyethylene glycol, preferably polyvinyl alcohol; the lipophilic nonionic surfactant in the middle phase of the double emulsion microsphere material and the inner phase of the single emulsion microsphere material is any one or more of Span 80, Span 60, Span 83, EM90, and polyglycerol ricinoleate, preferably EM90.

[0015] Furthermore, the external phase is an aqueous solution of any one or more materials selected from polyvinyl alcohol, sodium alginate, chitosan, and polyethylene glycol, with a mass concentration of 1 to 5%, for example, 1%, 2%, 3%, 4%, or 5%, preferably 3% polyvinyl alcohol.

[0016] In a specific embodiment, since the inner phase component contains a polymer compound (such as PVA), the middle phase contains polymer substances such as beeswax, and the outer phase also contains a polymer compound (such as PVA), the presence of these polymer compounds greatly increases the interfacial tension of the solution and improves the stability of the microspheres; at the same time, it greatly increases the viscosity of the solution, reduces the Reynolds number, and reduces the risk of turbulence caused by fluid disturbance.

[0017] Furthermore, in the preparation of double emulsion microspheres, the flow ratio of the internal phase, the intermediate phase, and the external phase is 1: (1~10): (1~100), for example, the flow ratio of the internal phase, the intermediate phase, and the external phase is 1:3:50, 1:5:50, 1:8:80, 1:2:20, etc. Preferably, the flow ratio of the internal phase, the intermediate phase, and the external phase is 1:3:30, for example, the flow rates of the internal phase, the intermediate phase, and the external phase are 10 ml / h, 30 ml / h, and 300 ml / h, respectively; in the preparation of single emulsion microspheres, the flow ratio of the internal phase to the external phase is (1~10): (1~100).

[0018] Preferably, during the double emulsion microsphere forming process, the inner phase solution is introduced first, and when it flows smoothly, the middle phase solution is introduced to shear with the inner phase solution to form stable single emulsion droplets; finally, the outer phase solution is introduced to allow the outer phase to wrap the middle phase single emulsion droplets to form W / O / W double emulsion droplets.

[0019] Furthermore, the microsphere receiving height is 5-50 cm, preferably 5-20 cm. During solidification in the receiving liquid, due to the influence of volume and gravity, large-sized microspheres are prone to irregular shapes or demulsification at the moment of collision. By optimizing the receiving height to 5-20 cm and coordinating the temperature gradient formed between the oil phase solidification temperature, microsphere forming temperature, and solidification temperature, the probability of irregularly shaped microspheres and demulsification can be greatly reduced.

[0020] Furthermore, the gradient cooling refers to the temperature being gradually cooled from the microsphere molding temperature to the receiving liquid temperature or room temperature in intervals of 10°C. The microsphere solidification principle is that the oil phase changes from liquid to solid as the temperature decreases. The temperature gradient is set at 5°C, 10°C, or 20°C, preferably 10°C, and the temperature is from T 成型 Gradually cooling to the receiving liquid temperature or room temperature, curing in the liquid outlet pipe and gradually cooling can reduce the stress accumulation generated during the microsphere curing process, which is beneficial to maintaining the good morphology of the microspheres.

[0021] The second object of the present invention is to provide a large-size microsphere preparation device with uniform particle size and regular shape, comprising an upper splint, a glass capillary, a lower splint and a support plate connected in sequence from top to bottom, an elastic gasket is also provided between the upper splint and the lower splint, the glass capillary is embedded in the elastic gasket, the glass capillary comprises an outer phase glass tube, an intermediate phase glass tube and an inner phase glass tube which are nested and connected in sequence, and the end of the outer phase glass tube away from the inner phase glass tube is connected to a liquid outlet tube.

[0022] Among them, the upper splint is penetrated by a plurality of liquid inlets, including an inner phase liquid inlet, an intermediate phase liquid inlet, and an outer phase liquid inlet, which are connected to the liquid inlet pipe. At the same time, the inner phase liquid inlet, the intermediate phase liquid inlet, and the outer phase liquid inlet are respectively connected to the inlets of the outer phase glass tube, the intermediate phase glass tube, and the inner phase glass tube. The upper splint, the lower splint, and the support plate are penetrated by threaded holes for screw fixing. The use of the support plate + screw fixing method limits the deformation of the chip splint at high temperature and avoids the risk of leakage.

[0023] The lower and upper surfaces of the upper and lower plates feature identical grooves that match the shape of the glass capillaries. The gaskets are made of PMMA and are transparent silicone, 0.1mm thick. They are shaped like irregular rings, with the internal cavity of the strips matching the groove structure of the glass capillaries. The microsphere molding temperature can reach up to 95°C. The gaskets prevent leakage caused by chip deformation at 95°C. By applying pressure to seal, the gasket avoids the potential leakage caused by gluing or other pressing methods at high temperatures. The gaskets can accommodate uneven sealing surfaces and minor deformations caused by high temperatures.

[0024] The inner diameter and outer diameter of the inner phase glass tube, the middle phase glass tube, and the outer phase glass tube are 0.7 mm and 1 mm, 1.25 mm and 1.9 mm, and 2.0 mm and 2.5 mm, respectively.

[0025] The chip support plate is provided with an internal cavity for observing the internal structure of the chip, and its material is aluminum alloy.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects.

[0027] 1. The present invention adopts microfluidic technology to prepare large-sized microspheres of millimeter scale. The microspheres are stably formed, with low probability of demulsification and irregular shape. The prepared large-sized microspheres have uniform particle size and regular morphology.

[0028] 2. The present invention effectively enhances the wettability of the interface between the middle phase and the inner phase by adding surfactants to both the inner phase and the middle phase, thereby improving the stability of microsphere molding.

[0029] 3. The present invention adopts a melting point of 50°C <T 熔 The oil phase of <85℃ can not only ensure that the emulsion solidifies at 30℃~50℃, but also slow down its solidification speed; at the same time, the receiving liquid temperature is set to (T 熔 -30)~(T 熔 -5)℃, since the microspheres are at T 熔 + (10 ~ 15) ℃ molding, in (T 熔 -30)℃~(T 熔 The microspheres are cured at -5℃. The temperature gradient formed among the oil phase solidification temperature, microsphere forming temperature and curing temperature can not only ensure the curing and forming, but also appropriately slow down the curing speed, so that the oil phase of the microspheres can retain appropriate fluidity at the moment of entering the receiving liquid surface, thereby repairing the irregularities caused by the droplet falling and colliding. The subsequent slow curing can greatly improve the stability of the microsphere molding, and the obtained microspheres have more uniform particle size and more regular shape.

[0030] 4. The present invention can also be cured in the liquid outlet pipe, and setting a gradient cooling for curing can reduce the stress accumulation generated during the microsphere curing process, which is conducive to maintaining the good morphology of the microspheres, thereby obtaining microspheres with regular morphology and uniform particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings: Figure 1 Schematic diagram of the structure of the microsphere preparation device of the present invention; Figure 2 Schematic diagram of the connection between the gasket and the glass capillary Figure 3 This is a morphology image of the microspheres prepared in Example 2; Figure 4 This is a morphology diagram of the microspheres prepared in Comparative Example 1; Figure 5 This is a morphology diagram of the microspheres prepared in Comparative Example 2; Figure 6 This is a morphology diagram of the microspheres prepared in Comparative Example 3; Figure 7 This is a morphology diagram of the microspheres prepared in Comparative Example 4; Figure 8 This is a morphology image of the microspheres prepared in Example 3; Figure 9 This is a morphology picture of the microspheres prepared in Example 4.

[0032] Markings and corresponding parts names in the accompanying drawings: 1-upper splint, 2-external phase glass tube, 3-middle phase glass tube, 4-inner phase glass tube, 5-elastic gasket, 6-lower splint, 7-support plate, 8-threaded hole, 9-inner phase liquid inlet, 10-middle phase liquid inlet, 11-external phase liquid inlet, 12-internal cavity, 13-liquid outlet pipe. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the embodiments and drawings. Obviously, the schematic implementation methods of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0034] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment," "an embodiment," "an example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combinations and / or subcombinations. Furthermore, it will be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes only and are not necessarily drawn to scale. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0035] In the description of the present invention, the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are merely for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present application.

[0036] At the same time, the terms "dispose," "assemble," "connect," and "connect" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediary, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention.

[0037] The "ranges" disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit, and the selected lower and upper limits define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive and may be arbitrarily combined, i.e., any lower limit may be combined with any upper limit to form a range.

[0038] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0039] Unless otherwise specified, all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0040] Unless otherwise specified, the terms "include" and "comprising" used in the present invention may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other substances not listed may also be included or that only the listed substances are included.

[0041] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0042] The technical solution of the present invention is further described in detail below with reference to the embodiments.

[0043] It should be noted that the experimental methods used in the examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art, unless otherwise specified, and can be obtained from commercial channels by those skilled in the art.

[0044] Example 1 A device for preparing large-scale microspheres with uniform particle size and regular shape, also known as a microfluidic chip, such as Figure 1 and 2 As shown, it includes: an upper splint 1, a glass capillary, a lower splint 6 and a support plate 7 connected in sequence from top to bottom, an elastic gasket 5 is also provided between the upper splint 1 and the lower splint 6, the glass capillary is embedded in the elastic gasket 5, and the glass capillary includes an outer phase glass tube 2, an intermediate phase glass tube 3 and an inner phase glass tube 4 which are nested and connected in sequence, and the end of the outer phase glass tube 2 away from the inner phase glass tube 4 is connected to a liquid outlet pipe 13.

[0045] Among them, the upper splint 1 is penetrated by a plurality of liquid inlets, including an inner phase liquid inlet 9, an intermediate phase liquid inlet 10, and an outer phase liquid inlet 11, which are connected to the liquid inlet pipe. At the same time, the inner phase liquid inlet 9, the intermediate phase liquid inlet 10, and the outer phase liquid inlet 11 are respectively connected to the inlets of the outer phase glass tube 2, the intermediate phase glass tube 3, and the inner phase glass tube 4 below. The upper splint 1, the lower splint 6, and the support plate 7 are penetrated by threaded holes 8 for screw fixing. The fixing method of the support plate 7 + screws is used to limit the deformation of the chip splint at high temperature, thereby avoiding the risk of leakage.

[0046] The lower surface of the upper clamping plate 1 and the upper surface of the lower clamping plate 6 have identical grooves that match the shape of the glass capillary tubes. The material is PMMA. The elastic gasket 5 is transparent silicone, 0.1mm thick, and shaped like a special-shaped annular strip. The internal cavity 12 of the strip matches the groove structure of the glass capillary tube. The microsphere molding temperature can reach up to 95°C. The installation of the gasket can prevent leakage caused by chip deformation at 95°C. The gasket applies pressure for sealing, avoiding the leakage that may occur at high temperatures such as glue adhesion or other pressing methods. The gasket itself can accommodate uneven sealing surfaces and minor deformation caused by high temperatures.

[0047] The inner diameter and outer diameter of the inner phase glass tube 4, the middle phase glass tube 3 and the outer phase glass tube 2 are 0.7 mm and 1 mm, 1.25 mm and 1.9 mm, 2.0 mm and 2.5 mm respectively.

[0048] The chip support plate 7 is provided with an internal cavity 12 for observing the internal structure of the chip, and the material thereof is aluminum alloy.

[0049] Example 2 Double emulsion microspheres were prepared according to the following steps: 1. Material preparation: Ultrasonicate the inner phase material (10% D-panthenol solution, containing 5% PVA) for 20 minutes to remove bubbles, and mix the middle phase material (liquid paraffin: beeswax = 6:4, the melting point of the middle phase is T 熔 = 60 ° C, add 3% EM90 surfactant) and the external phase material (3% PVA solution) were preheated in a 75 ° C water bath and sonicated for 1 hour; 2. Chip connection: Connect the inner phase, middle phase and outer phase solutions to the corresponding liquid inlets of the chip through the liquid inlet tubes respectively; 3. Microsphere molding: The constant temperature environment of microsphere molding is T 成型 =T 熔 +15℃ = 75℃, set the flow rates of the inner phase, middle phase, and outer phase to 10ml / h, 30ml / h, and 300ml / h, respectively. First, introduce the inner phase solution. Once it flows smoothly, introduce the middle phase solution, causing it to shear with the inner phase solution to form stable single emulsion droplets. Finally, introduce the outer phase solution, causing the outer phase to encapsulate the middle phase single emulsion droplets to form W / O / W double emulsion droplets. 4. Microsphere reception and solidification: The receiving liquid is ultrapure water, and the receiving liquid temperature is 30℃ (T 熔 -30℃), the microsphere receiving height is 20cm.

[0050] After testing, the double emulsion microsphere preparation process has good stability, the microsphere encapsulation efficiency is 99.65%, the average particle size is 2.01mm (CV value is 4.37%); the percentage of stable molding time in the microsphere molding stage is 99.33%, and the percentage of stable molding times is 100%; the percentage of irregular-shaped balls in the microsphere receiving and curing stage is 1.27%, and the percentage of demulsified balls is 2.24%. The morphology of the obtained product is as follows Figure 3 As shown; it can be seen that the method of the present invention can effectively reduce the probability of odd-shaped balls and demulsification, the molding stability is high, and the obtained microspheres have uniform particle size and regular morphology.

[0051] Comparative Example 1 The difference between this comparative example and Example 2 is that the oil phase formula does not contain a surfactant. The double emulsion microspheres were prepared according to the following steps: 1. Material preparation: Ultrasonicate the inner phase material (10% D-panthenol solution, containing 5% PVA) for 20 minutes to remove bubbles, and mix the middle phase material (liquid paraffin: beeswax = 6:4, melting point T 熔 = 60 ° C) and the external phase material (3% PVA solution) were preheated in a 75 ° C water bath and sonicated for 1 hour; 2. Chip connection: Connect the inner phase, middle phase and outer phase solutions to the corresponding liquid inlets of the chip through the liquid inlet tubes respectively; 3. Microsphere molding: The constant temperature environment for microsphere preparation is 75°C, and the flow rates of the inner phase, intermediate phase, and outer phase are set to 10 ml / h, 30 ml / h, and 300 ml / h, respectively; 4. Microsphere reception and solidification: The receiving liquid is ultrapure water, the receiving liquid temperature is 30°C, and the microsphere receiving height is 20 cm.

[0052] After testing, it was found that stable microsphere preparation could not be achieved without adding surfactant to the oil phase (intermediate phase). The percentage of stable molding time in the microsphere molding stage was 13.55%, the percentage of stable molding times was 9.10%, and the morphology of the obtained product was as follows: Figure 4 shown.

[0053] Comparative Example 2 The difference between this comparative example and Example 2 is that the oil phase formula is different, and the double emulsion microspheres are prepared according to the following steps: 1. Material preparation: Ultrasonicate the inner phase material (10% D-panthenol solution, containing 5% PVA) for 20 minutes to remove bubbles, and mix the middle phase material (liquid paraffin: beeswax = 8.5:1.5, melting point T 熔 = 32 ° C, add 3% EM90 surfactant) and the external phase material (3% PVA solution) were preheated in a 75 ° C water bath and sonicated for 1 hour; 2. Chip connection: Connect the inner phase, middle phase and outer phase solutions to the corresponding liquid inlets of the chip through the liquid inlet tubes respectively; 3. Microsphere molding: The constant temperature environment for microsphere preparation is 75°C, and the flow rates of the inner phase, intermediate phase, and outer phase are set to 10 ml / h, 30 ml / h, and 300 ml / h, respectively; 4. Microsphere reception and solidification: The receiving liquid is ultrapure water, the receiving liquid temperature is 30°C, and the microsphere receiving height is 20 cm.

[0054] After testing, microsphere molding can be achieved at 75°C, with an encapsulation rate of 97.98%, a stable molding time percentage of 99.34%, and a stable molding number percentage of 100%. However, it cannot be effectively cured at 30°C. Figure 5 As shown, the uncured microspheres are transparent green; this shows that since the melting point of the oil phase is 32°C and the receiving temperature is 30°C, the receiving temperature is too close to the melting point of the intermediate phase and the temperature difference is too small, resulting in the microspheres being unable to be effectively cured.

[0055] Comparative Example 3 The difference between this comparative example and Example 2 is that the receiving temperature is different, and the double emulsion microspheres are prepared according to the following steps: 1. Material preparation: Ultrasonicate the inner phase material (10% D-panthenol solution, containing 5% PVA) for 20 minutes to remove bubbles, and mix the middle phase material (liquid paraffin: beeswax = 6:4, melting point T 熔 = 60 ° C), add 3% EM90 surfactant) and the external phase material (3% PVA solution) preheated in a 75 ° C water bath and sonicated for 1 hour; 2. Chip connection: Connect the inner phase, middle phase and outer phase solutions to the corresponding liquid inlets of the chip through the liquid inlet tubes respectively; 3. Microsphere molding: The constant temperature environment for microsphere preparation is 75°C, and the flow rates of the inner phase, intermediate phase, and outer phase are set to 10 ml / h, 30 ml / h, and 300 ml / h, respectively; 4. Microsphere reception and solidification: The receiving liquid is ultrapure water, the receiving liquid temperature is 15°C, and the microsphere receiving height is 20 cm.

[0056] After testing, microsphere molding can be achieved at 75℃, with a stable molding time percentage of 99.53% and a stable molding number percentage of 100%. However, a large number of spindle-shaped tail-shaped balls (such as Figure 6 As shown in the figure), the probability of the irregular ball is 72.83%. It can be seen that due to the relationship between the receiving liquid temperature and T 熔 The temperature gradient from 60°C to 45°C increases the probability of irregular balls significantly compared to Example 2.

[0057] Comparative Example 4 The difference between this comparative example and Example 2 is that the receiving temperature and height are different, and the double emulsion microspheres are prepared according to the following steps: 1. Material preparation: Ultrasonicate the inner phase material (10% D-panthenol solution, containing 5% PVA) for 20 minutes to remove bubbles, and mix the middle phase material (liquid paraffin: beeswax = 6:4, melting point T 熔 = 60 ° C), add 3% EM90 surfactant) and the external phase material (3% PVA solution) preheated in a 75 ° C water bath and sonicated for 1 hour; 2. Chip connection: Connect the inner phase, middle phase and outer phase solutions to the corresponding liquid inlets of the chip through the liquid inlet tubes respectively; 3. Microsphere molding: The constant temperature environment for microsphere preparation is 75°C, and the flow rates of the inner phase, intermediate phase, and outer phase are set to 10 ml / h, 30 ml / h, and 300 ml / h, respectively; 4. Microsphere reception and solidification: The receiving liquid is ultrapure water, the receiving liquid temperature is 15°C, and the microsphere receiving height is 50 cm.

[0058] After testing, it was found that microspheres can be formed at 75°C, with a stable forming time percentage of 99.37% and a stable forming number percentage of 100%. However, a large amount of demulsification and floating occurred during the curing process (such as Figure 7 As shown in the figure), the demulsification rate is 55.32%. It can be seen that due to the relationship between the receiving liquid temperature and T 熔 The temperature gradient of 60℃ reaches 45℃. At the same time, the microsphere receiving height is relatively high. Large-sized microspheres are prone to produce irregular shapes or demulsification at the moment of collision, and the probability of demulsification is relatively high.

[0059] Example 3 The difference between this embodiment and embodiment 2 is that the double emulsion microspheres are prepared by solidifying in the liquid outlet pipe according to the following steps: 1. Material preparation: Ultrasonicate the inner phase material (10% D-panthenol solution, containing 5% PVA) for 20 minutes to remove bubbles, and mix the middle phase material (liquid paraffin: beeswax = 6:4, the melting point of the middle phase is T 熔 = 60 ° C), add 3% EM90 surfactant) and the external phase material (3% PVA solution) preheated in a 75 ° C water bath and sonicated for 1 hour; 2. Chip connection: Connect the inner phase, middle phase and outer phase solutions to the corresponding liquid inlets of the chip through the liquid inlet tubes respectively; 3. Microsphere molding: The constant temperature environment of microsphere molding is T 成型 =T 熔+15℃ = 75℃, set the flow rates of the inner phase, middle phase, and outer phase to 10ml / h, 30ml / h, and 300ml / h, respectively. First, introduce the inner phase solution. Once it flows smoothly, introduce the middle phase solution, causing it to shear with the inner phase solution to form stable single emulsion droplets. Finally, introduce the outer phase solution, causing the outer phase to encapsulate the middle phase single emulsion droplets to form W / O / W double emulsion droplets. 4. Microsphere curing: A temperature gradient is set in the liquid outlet pipe for curing. The gradient temperatures are 75°C, 65°C, 55°C, 45°C, and 35°C, respectively. The temperature is achieved by a condenser surrounding the liquid outlet pipe. 5. Microsphere collection: After solidification, the microspheres flow out of the liquid outlet tube and are collected with a receiving liquid. The receiving liquid is ultrapure water, the receiving temperature is 30°C, and the microsphere receiving height is 20 cm.

[0060] After testing, the double emulsion microsphere preparation process has good stability, the microsphere encapsulation efficiency is 98.82%, the average particle size is 1.97mm (CV value is 4.22%); the percentage of stable molding time in the microsphere molding stage is 99.13%, and the percentage of stable molding times is 100%; the percentage of irregular-shaped balls in the microsphere receiving and curing stage is 1.52%, and the percentage of demulsified balls is 2.02%. The morphology of the obtained product is as follows Figure 8 As shown, the particle size is uniform and the morphology is regular.

[0061] Example 4 Single emulsion microspheres were prepared according to the following steps: 1. Material Preparation: Preheat the internal phase material (liquid paraffin: beeswax = 6:4, melting point 60°C), add 3% EM90 surfactant), 5% β-carotene, and the external phase material (3% PVA solution) in a 75°C water bath and sonicate for 1 hour; 2. Chip connection: Connect the internal phase and external phase solutions to the corresponding liquid inlets of the chip through the liquid inlet tubes; 3. Microsphere molding: The constant temperature environment of microsphere molding is T 成型 =75℃, set the flow rates of the inner phase and outer phase to 30ml / h and 300ml / h respectively. First introduce the inner phase solution, and when it flows smoothly, introduce the outer phase solution, so that the outer phase wraps the inner phase to form single emulsion droplets; 4. Microsphere reception and solidification: The receiving liquid is ultrapure water, the receiving temperature is 30°C, and the microsphere receiving height is 20 cm.

[0062] After testing, the double emulsion microsphere preparation process has good stability, the microsphere encapsulation efficiency is 99.76%, the average particle size is 1.99mm (CV value is 3.58%); the percentage of stable molding time in the microsphere molding stage is 99.53%, and the percentage of stable molding times is 100%; the percentage of irregular-shaped balls in the microsphere receiving and curing stage is 1.43%, and the percentage of demulsified balls is 1.71%. The morphology of the obtained product is as follows: Figure 9 As shown, the particle size is uniform and the morphology is regular.

[0063] Finally, it should be noted that the above specific embodiments are only used to explain in detail the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above is only a specific implementation method of the present invention and is not used to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above specific embodiments, ordinary technicians in this field should understand that it is still possible to modify the technical solutions described in the above embodiments, or to replace or improve some or all of the technical features therein. These modifications, equivalent replacements, and improvements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and description of the present invention.

Claims

1. A method for preparing large-sized microspheres with uniform particle size and regular shape, characterized in that: include: Material preparation: Double emulsion microsphere materials include: inner phase, middle phase and outer phase. The inner phase includes aqueous solution containing active ingredients and hydrophilic polymer surfactant. The middle phase includes a melting point of 50℃. <T 熔 <85℃ oil phase and lipophilic nonionic surfactant, the external phase is an aqueous solution; the single emulsion microsphere material includes: an internal phase and an external phase, the internal phase includes a melting point of 50℃ <T 熔 An oil phase, an active ingredient and a lipophilic nonionic surfactant at a temperature of <85°C, wherein the external phase is an aqueous solution; Microsphere forming: Each material is introduced into the corresponding liquid inlet of the microfluidic chip to form microspheres. The microsphere forming temperature is T 熔 + (10~15) ℃; Microsphere reception and curing: The formed microspheres are cured by gradient cooling in the liquid outlet pipe and then dropped into the receiving liquid or the formed microspheres are directly dropped into the receiving liquid for curing. The receiving liquid temperature is (T 熔 -30)~(T 熔 -5)℃.

2. The method for preparing large-sized microspheres with uniform particle size and regular shape according to claim 1, characterized in that: 50℃ <T 熔 The oil phase below 85°C is composed of small molecular oils with a melting point below 45°C and solid waxes with a melting point above 60°C.

3. The method for preparing large-sized microspheres with uniform particle size and regular shape according to claim 2, characterized in that: The small molecule oil is any one or more of coconut oil, cocoa butter, susuba oil, shea butter, olive oil, palm oil, liquid paraffin, and lanolin; the solid wax is any one or more of beeswax, rice bran wax, carnauba wax, candelilla wax, microcrystalline wax, and solid paraffin.

4. The method for preparing large-sized microspheres with uniform particle size and regular shape according to claim 1, characterized in that: In the double emulsion microsphere material, the mass concentration of the hydrophilic polymer surfactant in the inner phase is 0.2%~10%, and the mass concentration of the lipophilic nonionic surfactant in the middle phase is 1%~4%; in the single emulsion microsphere material, the mass concentration of the lipophilic nonionic surfactant in the inner phase is 1%~4%.

5. The method for preparing large-sized microspheres with uniform particle size and regular shape according to claim 1, characterized in that: The hydrophilic polymer surfactant in the inner phase of the double emulsion microsphere material is any one or more of polyvinyl alcohol, sodium alginate, chitosan, and polyethylene glycol, and the lipophilic nonionic surfactant in the middle phase of the double emulsion microsphere material and the inner phase of the single emulsion microsphere material is any one or more of Span 80, Span 60, Span 83, EM90, and polyglycerol ricinoleate.

6. The method for preparing large-sized microspheres with uniform particle size and regular shape according to claim 1, characterized in that: The external phase is an aqueous solution of any one or more materials selected from polyvinyl alcohol, sodium alginate, chitosan, and polyethylene glycol, and the mass concentration is 1-5%.

7. The method for preparing large-sized microspheres with uniform particle size and regular shape according to claim 1, characterized in that: In the preparation of double emulsion microspheres, the flow ratio of the inner phase, the intermediate phase, and the outer phase is 1:(1~10):(1~100); in the preparation of single emulsion microspheres, the flow ratio of the inner phase to the outer phase is (1~10):(1~100).

8. The method for preparing large-sized microspheres with uniform particle size and regular shape according to claim 1, characterized in that: The microsphere receiving height is 5~50cm.

9. The method for preparing large-sized microspheres with uniform particle size and regular shape according to claim 1, characterized in that: The gradient cooling refers to the temperature being gradually cooled from the microsphere molding temperature to the receiving liquid temperature or room temperature at intervals of 10°C.

10. A preparation device used in the method according to any one of claims 1 to 9, characterized in that: The invention comprises an upper clamping plate (1), a glass capillary tube, a lower clamping plate (6) and a supporting plate (7) connected in sequence from top to bottom; an elastic gasket (5) is further provided between the upper clamping plate (1) and the lower clamping plate (6); the glass capillary tube is embedded in the elastic gasket (5); the glass capillary tube comprises an outer phase glass tube (2), an intermediate phase glass tube (3) and an inner phase glass tube (4) connected in sequence; and the end of the outer phase glass tube (2) away from the inner phase glass tube (4) is connected to a liquid outlet tube (13).

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