Microfluidic structure for promoting microcapsule formation by turbulent flow

Abstract

The present application discloses a microfluidic structure for promoting microcapsule formation by turbulence, comprising: a core channel, comprising a core cavity and two first channels leading out from the same core cavity, the two first channels merge at the end to form a mixing zone; a coating channel, comprising a coating cavity and a second channel leading out from the coating cavity, the second channel ends merge to form a premixing tube, the outlet of the premixing tube is connected to the mixing zone; a reaction channel, extending from the mixing zone to the microcapsule cavity. The microfluidic structure for promoting microcapsule formation by turbulence of the present application increases the turbulence of the core liquid by changing the structure of the core channel, so that the core liquid can gather in the mixing zone, which is conducive to the coating liquid coating the core liquid and improving the coating rate.

Description

Technical Field

[0001] The present application relates to the field of cell culture, and in particular to a microfluidic structure for promoting microcapsule formation by turbulence. Background Art

[0002] The use of microfluidic technology to produce cell microcapsules is a relatively gentle method and is more suitable for situations where the number of microcapsules required is not high, the preparation cost is low, and the mechanical damage to cells is low. However, the existing technology has not yet overcome the problem of low cell coating rate. Summary of the invention

[0003] The purpose of the present application is to at least partially overcome the deficiencies of the prior art and to provide a microfluidic structure that promotes microcapsule formation by turbulence, thereby increasing the cell coating rate by increasing the turbulence of the core fluid.

[0004] In order to achieve the above technical objectives, the technical solutions adopted in this application are as follows:

[0005] A microfluidic structure for promoting microcapsule formation by turbulence, comprising:

[0006] A core pipeline, comprising a core cavity and two first channels leading out from the same core cavity, wherein the two first channels merge at the ends to form a mixing zone;

[0007] A coating pipeline, comprising a coating chamber and a second channel leading out of the coating chamber, the ends of the second channels merge to form a premixing tube, and the outlet of the premixing tube is connected to the mixing zone;

[0008] The reaction channel extends from the mixing zone to the microcapsule cavity.

[0009] Preferably, an intermediate cavity is provided between the core cavity and the first channel, and the intermediate cavity is at least partially defined by an elastic film.

[0010] Further preferably, the bottom of the core cavity is higher than the bottom of the middle cavity, the core cavity and the middle cavity are connected by a connecting pipe, and the connecting pipe is arranged near the bottom of the core cavity.

[0011] Optionally, the connecting pipe is arranged horizontally, or arranged in an inverted U-shaped structure.

[0012] Further preferably, at least one of the first channels is provided with a blocking block near the inner wall of the mixing zone for changing the inner diameter of the first channel.

[0013] Furthermore, at least two coating pipelines are provided for loading different coating components.

[0014] Further, the reaction pipe extends in a curved form; or / and the reaction pipe extends in a reduced diameter form.

[0015] Preferably, the core cavity, the coating cavity and the microcapsule cavity are respectively provided with openings connected to the pump body.

[0016] Further preferably, the microfluidic structure for promoting microcapsule formation by turbulence comprises an upper cover plate and a lower cover plate which are covered.

[0017] Optionally, the first pipeline is respectively arranged in the upper cover plate and the lower cover plate; and the second pipeline is defined by the upper cover plate and the lower cover plate.

[0018] Optionally, the core cavity, coating cavity, reaction channel and microcapsule cavity are defined by an upper cover plate and a lower cover plate, respectively.

[0019] Compared with the prior art, this application has the following advantages:

[0020] (1) The microfluidic structure of the present application that promotes the formation of microcapsules by turbulence increases the turbulence of the core liquid by changing the structure of the core channel, so that the core liquid can gather in the mixing zone, which is beneficial for the coating liquid to coat the core liquid and improve the coating rate.

[0021] (2) The microfluidic structure for promoting the formation of microcapsules by turbulence in the present application makes full use of the three-dimensional structure of the upper and lower cover plates, distributes the core channel and the coated channel in three dimensions, and increases the turbulence degree of the fluid in the core channel.

[0022] (3) The microfluidic structure for promoting the formation of microcapsules by turbulence in the present application has an intermediate cavity between the core cavity and the first pipe. On the one hand, the turbulence degree of the core liquid can be increased by squeezing the elastic film of the intermediate cavity. On the other hand, the intermediate cavity and the core cavity are connected by a connecting tube, and the core liquid in the intermediate cavity is supplemented by the siphon principle, thereby reducing the contamination and disturbance of the core liquid in the core cavity.

[0023] (4) The microfluidic structure of the present application for promoting microcapsule formation by turbulence is simple in design and can be easily implemented on a general microfluidic chip, thus having high applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic longitudinal section diagram of the microfluidic structure for promoting microcapsule formation by turbulence in the present application.

[0025] Figure 2 This is a schematic cross-sectional view of the microfluidic structure for promoting microcapsule formation by turbulent flow in the present application.

[0026] Figure 3 Schematic diagram of the fluid flow direction of a part of the microfluidic structure for promoting microcapsule formation by turbulence in the present application. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] The microfluidic structure for promoting the formation of microcapsules by turbulent flow in the present application is expected to prepare microcapsules in the following manner: the microcapsules to be prepared in the present application include a core layer and a coating layer, wherein the core layer is composed of a core liquid, and the core liquid generally contains a mixed solution of at least one of microorganisms, cytokines, and cells and a sodium alginate solution, or the core liquid contains a mixed solution of at least one of microorganisms, cytokines, and cells and sodium methylcellulose; the coating layer is formed by cross-linking the coating liquid, and the coating liquid contains a shell liquid and an oil emulsion, and the shell liquid contains a sodium alginate solution, and the oil emulsion contains a mixed emulsified solution of mineral oil and calcium chloride. The two components in the core liquid and the coating liquid need to be stored separately, and the three are controlled to converge at a set flow rate, so that the core liquid and the coating liquid are mixed into a pre-microcapsule liquid at the front end of the reaction pipe 3, and the pre-microcapsule liquid enters the reaction pipe 3 for a cross-linking reaction, and the microcapsules formed after the reaction are collected at the sample outlet of the reaction pipe 3.

[0029] In order to realize the above reaction process, the microfluidic structure of the turbulent flow promoting microcapsule formation of the present application is as follows:

[0030] The starting point of the flow of the whole fluid of the microfluidic structure formed by turbulent flow-promoting microcapsules is defined as the front end, the end point of the flow is defined as the rear end, the opening side where the core liquid and the coating liquid are injected is defined as the upper end, and the opposite is defined as the lower end. Thus, the left and right ends of the microfluidic structure formed by turbulent flow-promoting microcapsules are identified, such as Figure 1 and Figure 2 shown.

[0031] The microfluidic structure for promoting microcapsule formation by turbulence in the present application comprises:

[0032] The core pipe 1 comprises a core cavity 11 and two first channels 12 extending from the same core cavity 11, wherein the two first channels 12 merge at the ends to form a mixing zone 31;

[0033] The coating pipeline 2 comprises a coating chamber 21 and a second channel 22 leading out from the coating chamber 21, the ends of the second channels 22 merge to form a premixing tube 23, and the outlet of the premixing tube 23 is connected to the mixing zone 31;

[0034] The reaction pipe 3 extends from the mixing zone 31 to the microcapsule cavity 4 .

[0035] Furthermore, the core pipe 1 is used to drain the core liquid from the core cavity 11 to the reaction pipe 3. The core liquid in the embodiment of the present application is a suspension. The core liquid standing still in the container will cause the cells or macromolecules therein to precipitate, resulting in laminar flow of the core liquid, resulting in uneven coating; but if a micro-injection pump is used for repeated suction, it will increase the mechanical damage to the cells and easily introduce bubbles into the pipe. If the bubbles are coated in the microcapsules, the coating rate of the microcapsules will be further reduced.

[0036] In one possible implementation, the core pipeline 1 of the present application includes a core cavity 11 and two first channels 12 leading out from the core cavity 11, the two first channels 12 are respectively arranged at the upper end and the lower end, and the ends of the two first channels 12 merge into an outlet, and a mixing zone 31 is formed at the outlet. In the process of the core cavity 11 being continuously filled, the core liquid first overflows through the first channel 12 at the lower end, forming a smaller-scale core liquid aggregation in the mixing zone 31; then the core liquid overflows through the first channel 12 at the upper end, and the core liquids from the upper and lower ends merge to form a larger-scale core liquid aggregation zone. Furthermore, as Figure 1 and Figure 3 As shown, the two first channels 12 are partially connected, so the core liquid overflowing from the upper first channel 12 will partially flow back to the lower first channel 12, increasing the turbulence and suspension density at the outlet of the lower first channel 12, making the suspension density remaining in the mixing zone 31 higher.

[0037] Furthermore, based on the previous embodiment, a blocking block 16 may be provided on the inner wall of at least one first channel 12 near the outlet, and the inner diameter of the first channel 12 may be changed at the location of the blocking block 16 to achieve turbulence enhancement. Figure 1 As shown, a blocking block 16 is preferably provided on the inner wall of the first channel 12 at the lower end to enhance the turbulence of the fluid behind the blocking block 16 and to prevent a large amount of core liquid from flowing back into the core cavity 11 .

[0038] A more preferred embodiment is to set an intermediate cavity 13 between the core cavity 11 and the first channel 12, and the core cavity 11 and the intermediate cavity 13 are connected by a connecting tube 15, and the first channel 12 is directly drawn from the intermediate cavity 13. Thus, the intermediate cavity 13 can act as a buffer, further reducing the contamination and disturbance of the solution in the core cavity 11, facilitating the recovery and reuse of the core liquid in the core cavity 11, and when the core liquid contains cells, the mechanical stress on the cells can be reduced. Preferably, a siphon device can be formed between the intermediate cavity 13 and the core cavity 11, so that the core liquid in the core cavity 11 is automatically replenished into the intermediate cavity 13, keeping the intermediate cavity 13 full, and reducing the introduction of bubbles into the microfluidic structure that promotes the formation of turbulent microcapsules. Specifically, the bottom of the core cavity 11 is set higher than the bottom of the intermediate cavity 13, and the connecting tube 15 is set close to the bottom of the core cavity 11. In order to make the connecting pipe 15 form an "inverted U-shaped" structure between the core cavity 11 and the middle cavity 13, the connecting pipe 15 can be arranged horizontally or in an inverted U-shaped structure, but the U-shape should be avoided.

[0039] Furthermore, the middle cavity 13 is at least partially defined by the elastic film 14, so that the middle cavity 13 can be deformed by external force, thereby promoting the reciprocating flow of the fluid in the first pipe and further increasing the turbulence in the first pipe. Figure 1 The middle cavity 13 is defined by the upper chip and the lower chip, wherein the elastic film 14 is respectively embedded in the upper chip and the lower chip and close to the upper and lower surfaces. The external force for squeezing the elastic film 14 can be provided by manpower or by a device that can drive the elastic film 14 to vibrate or deform, such as an air pump. The degree and frequency of squeezing can be determined by experiments, and the material and elastic properties of the elastic film 14 can also be determined by experiments.

[0040] The coating conduit 2 is used to guide the coating liquid from the coating cavity 21 to the reaction conduit 3, and embed the core liquid in the mixing zone 31. It includes a coating cavity 21 and a second channel 22 led out from the coating cavity 21, and the second channel 22 is connected to the mixing zone 31. Usually, two coating cavities 21 are set in a microfluidic structure for turbulent microcapsule formation, which are used to load different components respectively, and are respectively configured with a second channel 22. According to the function of the coating liquid, it is necessary to merge at the end of the second channel 22 to form a premixing tube 23, the outlet of the premixing tube 23 is connected to the mixing zone 31, and the coating liquid flow rate is controlled so that the coating liquid can embed the core liquid gathered in the mixing zone 31.

[0041] In a possible implementation, based on the first channel 12 being arranged at the upper end and the lower end, the two second channels 22 can be arranged at the left end and the right end respectively to make full use of the three-dimensional space, such as Figure 2As shown. Another possible implementation is that the length and inner diameter of the premixing tube 23 can be determined according to experiments, and even how to set the turbulence enhancement structure inside the premixing tube 23 can also be determined according to experiments, the purpose is to mix the coating liquids from different second channels 22 to form microcapsule pre-liquids, and then push them to the mixing zone 31 to embed the core liquid. Further, in order to ensure the integrity of embedding and the sequential embedding of multiple microcapsules, the flow rate in the second channel 22 is controlled to be greater than the flow rate in the first channel 12, so that the coating liquid can flow laminarly on the surface of the aggregated core liquid, so that the core liquid is embedded in a spherical form in the subsequent flow, and the microcapsule precursor mixed in the mixing zone 31 can be cross-linked in the process of being continuously pushed, and the cross-linking reaction is completed when it reaches the microcapsule cavity 4 through the reaction pipe 3. A possible implementation is that the flow rate of the first channel 12 is controlled at 50-150 μL / h, and the flow rate of the second channel 22 is controlled at 2-10 mL / h.

[0042] The reaction channel is used to provide a place for cross-linking of microcapsules. The speed and degree of cross-linking reaction of gel materials such as sodium alginate are different. Therefore, increasing the length of the reaction channel by a circuitous way within a limited volume space is one of the ways to extend the reaction time. The reaction channel in this embodiment can be set to a serpentine, a zigzag, a flat spiral, or a combination of these shapes. Furthermore, appropriately increasing the degree of turbulence in the reaction channel is also conducive to making the shape of the microcapsules closer to a sphere, which can be achieved by setting several sections of variable diameter sections in the reaction channel.

[0043] In this embodiment, the microfluidic structure formed by the turbulence-promoting microcapsules is formed by bonding two upper and lower covering PDMS chips formed by epoxy resin SU-8 mold technology, and is divided into an upper cover plate I and a lower cover plate II. A number of grooves are etched on the mating surfaces of the upper cover plate I and the lower cover plate II, respectively, to form the aforementioned cavity or channel of the microfluidic structure constituting the turbulence-promoting microcapsules. Specifically, the first pipeline is respectively arranged in the upper cover plate I and the lower cover plate II, that is, the upper cover plate I includes a complete first channel 12 at the upper end, and the lower cover plate II includes a complete first channel 12 at the lower end; the second pipeline is defined by the upper cover plate I and the lower cover plate II, and the core cavity 11, the coating cavity 21, the reaction pipeline 3, the microcapsule cavity 4 and the middle cavity 13 are respectively defined by the upper cover plate I and the lower cover plate II, that is, the second pipeline, the core cavity 11, the coating cavity 21, the reaction pipeline 3, the microcapsule cavity 4 and the middle cavity 13 are respectively arranged in the upper cover plate I and the lower cover plate II, and the upper cover plate I and the lower cover plate II are covered to form a complete structure. The connecting pipe 15 can be set in the upper cover plate I and the lower cover plate II according to the actual design position. Furthermore, the core cavity 11, the coating cavity 21, and the microcapsule cavity 4 need to respectively have openings connected to the pump body (not shown). Preferably, the openings of the core cavity 11 and the coating cavity 21 are opened at the top, and the opening of the microcapsule cavity 4 can be opened at the bottom.

[0044] In summary, the microfluidic structure for promoting microcapsule formation by turbulence of the present application includes: a core channel 1, including a core cavity 11 and two first channels 12 leading from the same core cavity 11, the two first channels 12 merge at the end to form a mixing zone 31; a coating channel 2, including a coating cavity 21 and a second channel 22 leading from the coating cavity 21, the second channel 22 merges at the end to form a premixing tube 23, the outlet of the premixing tube 23 is connected to the mixing zone 31; a reaction channel 3, extending from the mixing zone 31 to the microcapsule cavity 4. The microfluidic structure for promoting microcapsule formation by turbulence of the present application increases the turbulence of the core liquid by changing the structure of the core channel 1, so that the core liquid can gather in the mixing zone 31, which is beneficial for the coating liquid to coat the core liquid and improve the coating rate.

[0045] The above embodiments are preferred implementation modes of the present application, but are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present application should be equivalent replacement methods and are included in the protection scope of the present application.

Claims

1. A microfluidic structure for promoting microcapsule formation by turbulence, characterized in that: include: The core pipeline comprises a core cavity and two first channels leading out from the same core cavity, wherein the two first channels merge at the ends to form a mixing zone; at least one of the first channels is provided with a blocking block near the inner wall of the mixing zone to change the inner diameter of the first channel; A coating pipeline, comprising a coating chamber and a second channel leading out of the coating chamber, the ends of the second channels merge to form a premixing tube, and the outlet of the premixing tube is connected to the mixing zone; A reaction conduit extending from the mixing zone to the microcapsule cavity; The microfluidic structure for promoting microcapsule formation by turbulence comprises an upper cover plate and a lower cover plate which are covered together, and the core cavity, the coating cavity, the reaction channel and the microcapsule cavity are respectively defined by the upper cover plate and the lower cover plate.

2. The microfluidic structure for promoting microcapsule formation by turbulence according to claim 1, characterized in that: An intermediate cavity is arranged between the core cavity and the first channel, and the intermediate cavity is at least partially defined by an elastic film.

3. The microfluidic structure for promoting microcapsule formation by turbulence as claimed in claim 2, characterized in that: The bottom of the core cavity is higher than the bottom of the middle cavity. The core cavity and the middle cavity are connected by a connecting pipe, and the connecting pipe is arranged near the bottom of the core cavity.

4. The microfluidic structure for promoting microcapsule formation by turbulence as claimed in claim 3, characterized in that: The connecting pipe is arranged horizontally or in an inverted U-shaped structure.

5. The microfluidic structure for promoting microcapsule formation by turbulence according to claim 1, characterized in that: The coating pipelines are provided with at least two for loading different coating components.

6. The microfluidic structure for promoting microcapsule formation by turbulence according to claim 1, characterized in that: The reaction pipe extends in a curved form; or / and the reaction pipe extends in a reduced diameter form.

7. The microfluidic structure for promoting microcapsule formation by turbulence according to claim 1, characterized in that: The core cavity, the coating cavity and the microcapsule cavity are respectively provided with openings communicating with the pump body.

8. The microfluidic structure for promoting microcapsule formation by turbulence according to claim 1, characterized in that: The first pipeline is respectively arranged in the upper cover plate and the lower cover plate; the second pipeline is defined by the upper cover plate and the lower cover plate.

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