A microfluidic chip and method for nanoparticle synthesis

Abstract

The application discloses a micro-fluidic chip and method for nanoparticle synthesis, the micro-fluidic chip comprises a sample inlet flow channel and a mixing flow channel, the sample inlet flow channel comprises a plurality of material sample inlet flow channels, at least comprising a first material sample inlet flow channel for conveying a first material and a second material sample inlet flow channel for conveying a second material; at least one mixing unit is arranged in the mixing flow channel, the mixing unit is defined by a boundary structure to form a fluid mixing area, and a flow splitting structure is arranged in the fluid mixing area; the plurality of material sample inlet flow channels are communicated with the mixing flow channel, so that each material fluid converges in the mixing flow channel, and flow splitting and mixing occur when flowing through the at least one mixing unit, thereby forming a nanoparticle product fluid and flowing out of the mixing flow channel. The application can improve the mixing effect and structural adaptability, and is favorable for improving the particle size distribution of the nanoparticles and the preparation consistency.

Description

Technical Field

[0001] This invention relates to the fields of microfluidic technology and nanomaterial preparation technology, specifically to a microfluidic chip and method for nanoparticle synthesis. Background Technology

[0002] The combination of microfluidic chips and nanoparticle synthesis is a cutting-edge research area in the cross-disciplinary integration of nanotechnology and microfluidics in recent years. Microfluidic chips provide a novel "miniature laboratory" environment for nanoparticle synthesis. By manipulating fluid behavior at the micrometer to nanometer scale, microfluidic technology achieves extreme controllability and high throughput in the nanoparticle synthesis process.

[0003] Currently, the mainstream microfluidic technology used for nanoparticle synthesis achieves mixing by modifying the structure of microchannels to generate laminar, eddy, or chaotic convection. Microscale mixing mainly relies on molecular diffusion after laminar flow is formed; therefore, different mixing structure designs have significant differences in mixing efficiency and nanoparticle quality.

[0004] High mixing efficiency means that laminar mixing within the chip can occur stably and rapidly through special flow channel design. Low pressure drop means that the movement of the liquid can be controlled with lower energy input. Stability means good repeatability. Wide flow rate range means high mixing efficiency from low-flow-rate laminar mixing to high-flow-rate turbulent mixing, which is a necessary condition for scale-up production using the same flow channel structure. Currently, microfluidic chips capable of synthesizing nanoparticles efficiently, with low pressure drop, stably, and over a wide flow rate range are still relatively limited. From experimental-level testing of nanoparticle synthesis to mass production of nanoparticles, scale-up consistency still presents certain challenges.

[0005] To overcome the aforementioned technical problems, it is necessary to design a microfluidic chip that is efficient, has low pressure drop, is stable, has a wide flow rate range, and is easy to fabricate for the synthesis, research and development, and production of nanoparticles. Summary of the Invention

[0006] To address the problems of limited mixing efficiency, insufficient contact between different materials, and poor particle size and distribution consistency in existing nanoparticle synthesis processes, this invention provides a microfluidic chip and method for nanoparticle synthesis. The microfluidic chip includes a sample inlet channel and a mixing channel. The sample inlet channel comprises multiple material inlet channels, and the mixing channel contains at least one mixing unit. Each mixing unit is defined by a boundary structure to form a fluid mixing region, and a flow-diverting structure is provided within the fluid mixing region. This allows the fluid materials, after converging within the mixing channel, to undergo diversion and mixing as they flow through the mixing unit, thereby improving the mixing effect and uniformity, and contributing to improved nanoparticle size distribution and preparation consistency.

[0007] According to a first aspect of the present invention, a microfluidic chip for nanoparticle synthesis is provided, comprising microchannels, the microchannels including an inlet channel and a mixing channel; The sample inlet channel includes multiple material inlet channels, including at least a first material inlet channel for conveying a first material and a second material inlet channel for conveying a second material; The mixing channel is provided with at least one mixing unit, the mixing unit is defined by a boundary structure to form a fluid mixing region, and a flow splitting structure is provided within the fluid mixing region; The plurality of material inlet channels are connected to the mixing channel so that the material fluids converge in the mixing channel and are split and mixed when flowing through the at least one mixing unit, thereby forming a nanoparticle product fluid and flowing out from the mixing channel.

[0008] In some technical solutions, the number of the first material inlet channels is N2, where N2 ≥ 1; When N2≥2, the outlet ends of at least two first material inlet channels are distributed on both sides of the outlet end of the second material inlet channel, and N2 first material inlet channels and the second material inlet channels are all connected to the mixing channel.

[0009] In some technical solutions, the angle between the first material inlet channel and the second material inlet channel is 0° to 180°; Preferably, the first material inlet channel, the second material inlet channel, and the mixing channel form a T-shaped inlet structure, a Y-shaped inlet structure, or a cross-shaped inlet structure.

[0010] In some technical solutions, the outlet width of the mixing unit, the length of the flow splitting structure, and the maximum width of the mixing unit satisfy a proportional relationship, preferably 1:2:4; under the condition that the proportional relationship remains unchanged, the mixing unit and its internal flow splitting structure can be enlarged or reduced proportionally as a whole to adapt to different total injection flow rates.

[0011] Preferably, the total flow rate range is 4-400 ml / min.

[0012] In some technical solutions, at least some of the multiple material injection channels are connected to the mixing channel at different positions along the fluid flow direction, so that different materials enter and participate in mixing at different stages of the mixing channel, and the mixing units at different positions in the mixing channel are scaled proportionally as a whole according to the mixing requirements of the corresponding stage.

[0013] It should be noted that the listed proportional relationships are preferred embodiments, used to illustrate that the present invention can achieve performance continuity through size linkage changes; in practical applications, as long as the relevant structural dimensions maintain corresponding proportions that are conducive to diversion and mixing, and can be adapted to different injection conditions through overall size adjustment, they can also fall within the technical concept scope of the present invention.

[0014] In some technical solutions, the hybrid unit is any one of a circle, a polygon, or an irregular shape, preferably a hexagonal structure; The diversion structure is a circle, polygon, or irregular shape, preferably a concave shape.

[0015] In some technical solutions, the mixing unit, the mixing channel, and the sample inlet channel are all or partly disposed in the same plane; and / or, The height of the diversion structure is less than or equal to the depth of the mixing unit, and the depth of the mixing unit is greater than or equal to the outlet width of the mixing unit.

[0016] In some technical solutions, the inlet width of the sample inlet channel is greater than the outlet width, and the outlet widths of the first and second material sample inlet channels are equal to the inlet width of the first mixing unit.

[0017] The width relationship between the inlet and outlet ends of the sample inlet channel defined in this embodiment serves to create a contraction and guiding effect on the material before it flows into the confluence area, and to match the inlet width of the first mixing unit, thereby facilitating the stable entry of the confluenced material into the first mixing unit. This helps to reduce flow turbulence or local stagnation at the confluence point.

[0018] In some technical solutions, the microfluidic chip further includes: Multiple material inlets are connected to the upstream of the multiple material injection channels, respectively.

[0019] A material outlet is connected downstream of the mixing channel.

[0020] In some technical solutions, the microfluidic chip further includes a substrate and a cover plate, and the microchannel, material inlet and material outlet are respectively independently disposed on the substrate and / or the cover plate; The substrate and cover plate are sealed together, preferably by means of hot pressing, laser bonding, plasma bonding or threaded fastening of the sealing element. Preferably, the substrate and the cover plate are made of one or more materials selected independently from PDMS, glass, COC and stainless steel.

[0021] According to a second aspect of the present invention, a method for synthesizing nanoparticles is further provided, employing the above-described microfluidic chip, comprising the following steps: Each material to be mixed is introduced into its corresponding material inlet channel according to a preset flow rate ratio; The materials are introduced into the mixing channel through the material inlet channel and then merged. The materials that have merged are then passed through the mixing unit in the mixing channel, where they are separated and mixed. The nanoparticle product fluid collected from the microfluidic chip.

[0022] This method is simple and can be directly integrated with the structural features of the chip. The preset flow rate ratio can be adjusted according to the target nanoparticle type, material concentration, and particle size requirements, and is not limited to a single value. Continuous nanoparticle formation can be achieved by controlling the two-phase flow input conditions and combining them with the aforementioned chip structure.

[0023] The present invention, by employing the above technical solution, has at least the following beneficial effects: 1. By setting up a structure that connects the sample inlet channel and the mixing channel, the present invention enables the first and second materials to form initial contact at the confluence point before entering the mixing channel. Furthermore, the first mixing unit enables rapid introduction and subsequent continuous mixing, which helps to shorten the distance from material confluence to full contact, improves the mixing efficiency within the microfluidic chip, and thus provides a more uniform and stable microscopic reaction environment for the formation of nanoparticles.

[0024] 2. This invention employs a structure in which two first material inlet channels are symmetrically distributed on both sides of a second material inlet channel. Multiple mixing units are sequentially connected in series within the mixing channel, and each mixing unit has a flow-dividing structure, allowing continuous flow-dividing and mixing of the fluid during flow. This effectively improves the mixing effect and is beneficial for improving the particle size distribution and preparation consistency of nanoparticles.

[0025] 3. This invention designs the mixing unit's outlet width, the length of the flow distribution structure, and the maximum width of the mixing unit proportionally. This allows the mixing unit and its internal flow distribution structure to be scaled up or down proportionally while maintaining the proportional relationship. This adapts to different total sample flow rates, improving the chip's structural adaptability and operational flexibility under varying throughput conditions. Furthermore, at least some of the material inlet channels can be connected to the mixing channel at different locations along the fluid flow direction, allowing different materials to enter and participate in mixing at different stages of the mixing channel. The mixing units at different locations can be scaled up proportionally according to the mixing requirements of the corresponding stage. This facilitates meeting the needs of multi-material staged entry and staged mixing, and maintains good mixing effects and preparation stability under varying flow rates and composition conditions at different stages.

[0026] 4. The mixing unit of this invention adopts a polygonal structure and can be optimized by combining the shape, through-flow arrangement, and quantity configuration of the flow distribution structure, thereby forming a more effective fluid disturbance and mixing path within the limited chip space. This structure is beneficial for enhancing the mixing effect and for forming a relatively stable continuous flow process inside the chip.

[0027] 5. The nanoparticle synthesis method provided by this invention has a simple process and strong structural adaptability, and is especially suitable for the preparation of lipid-based nanoparticles, showing good application prospects for liposome nanoparticle systems. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the microchannel structure in Example 1; Figure 2 This is a schematic diagram of the microfluidic chip structure in Example 1; Figure 3 This is a schematic diagram of the microchannel structure in Example 2; Figure 4 This is a schematic diagram of the microfluidic chip structure in Example 2; Figure 5 This is a schematic diagram of the microchannel structure in Example 3; Figure 6 This is a schematic diagram of the microchannel structure in Example 4; Figure 7 This is a simulated concentration distribution diagram of the three sample inlet channels flowing into a single mixing unit in Example 5; Figure 8 This is a schematic diagram of the structure of multiple hybrid units in Example 6; Figure 9 This is a simulated concentration distribution diagram of the three sample inlet channels flowing into multiple mixing units in Example 6; Figure 10 This is a scatter plot of the number of mixing units through which the T-shaped injection channel provided in Example 7 flows and the mixing index MI. Figure 11 This is a scatter plot of the number of mixing units through which the Y-shaped injection channel flows and the mixing index MI provided in Example 7; Figure 12 This is a scatter plot of the number of mixing units through which the cross-shaped sample inlet channel provided in Example 7 flows and the mixing index MI. Figure 13 This is a scatter plot of the channel depth versus mixing index MI verified in Example 8; Figure 14 This is a scatter plot of the channel depth versus mixing index MI verified in Example 8. Figure 15 This is a scatter plot of the channel depth versus mixing index MI verified in Example 8; Figure 16 This is a graph showing the relationship between the particle size, polydispersity index (PDI) and flow rate of the nanoparticles synthesized in Example 9. Figure 17 This is a graph showing the relationship between the particle size, PDI, and flow rate of the nanoparticles synthesized in Example 10. Figure 18 This is a graph showing the relationship between the particle size, PDI and flow rate of the synthesized nanoparticles when the outlet width of the mixing unit in Example 11 is 0.15 mm. Figure 19 This is a graph showing the relationship between the particle size, PDI and flow rate of the synthesized nanoparticles when the outlet width of the mixing unit in Example 11 is 0.3 mm. Figure 20 This is a graph showing the relationship between the particle size, PDI and flow rate of the synthesized nanoparticles when the outlet width of the mixing unit in Example 11 is 0.6 mm. Figure 21 This is a graph showing the relationship between the particle size, PDI and flow rate of the nanoparticles synthesized by SM102 LNP in Example 12. Figure 22 This is a diagram showing the experimental results of lipid-based nanoparticle synthesis using a microfluidic chip under high flow rate conditions in Example 13. Detailed Implementation

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the specific implementation methods of this application will be described below with reference to the accompanying drawings. The manufacturing and fabrication methods of the chip, such as the composition of the "cover plate" and "substrate," are merely one application method and should not be considered as limiting the scope of this patent. The accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort. Adjustments and improvements made without departing from the concept of this application are all within the protection scope of this application.

[0030] To keep the drawings concise, the figures in this application only schematically show the parts relevant to this application, and they do not represent the actual structure of the product. Furthermore, to make the drawings concise and easy to understand, some figures only schematically show parts of components with the same structure or function; in reality, there may be more or fewer components with the same structure or function.

[0031] In this application, unless otherwise expressly specified and limited, ordinal numbers, such as "first," "second," etc., are used only to distinguish and describe related objects, and should not be construed as indicating or implying the relative importance or order between related objects; furthermore, they do not represent the number of related objects. "And / or" is used to describe the relationship between related objects, which includes any relationship between the related objects; for example, "a and / or b" includes: "a alone," "b alone," or "a and b." The terms "installation" and "connection" should be interpreted broadly; for example, "installation" can be direct installation or installation via other components; "connection" can be direct connection or connection via other components. The term "relative arrangement" includes parallel relative or relative at a certain angle, the angle of which is not limited and is determined according to the number of objects in the relative arrangement.

[0032] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) are relative rather than absolute when describing the structure and movement of the various components, and are not intended to limit the direction of the product during actual use.

[0033] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0034] Example 1

[0035] This embodiment provides a microfluidic chip, such as Figure 1-2 As shown, the microfluidic chip includes a substrate and a cover plate. The substrate contains microchannels, including an inlet channel and a mixing channel. The cover plate has two material inlets and one material outlet. The material inlets are surrounded by the aqueous inlet channel and symmetrically distributed on both sides of the mixing channel. Furthermore, the two material inlets are connected to the organic phase inlet channel and the aqueous phase inlet channel, respectively, while the material outlet is connected to the outlet of the mixing channel. There are three sample inlet channels: one for the organic phase, with its outlet facing the same direction as the mixing channel; and two for the aqueous phase, with their outlets symmetrically distributed on either side of the organic phase channel. The two aqueous phase channels share a common inlet point. Furthermore, the two aqueous phase channels are of equal length, and their outlets form a 180° angle. All inlet channels have a constriction structure at their outlets, resulting in equal outlet widths after constriction, which are also equal to the inlet width of the mixing unit.

[0036] The mixing channel is equipped with N1 series-connected mixing units, where N1 ≥ 2, preferably 3-8 units; in this embodiment, there are 6 mixing units. The inlet of the mixing channel is also the inlet of the mixing unit. The mixing unit has a polygonal structure and includes a flow divider. The inlet width of the mixing unit is equal to the outlet width of the sample inlet channel. The inlet width of the mixing unit is between 0.1 mm and 3 mm, and can be scaled up proportionally to match different sample inlet velocities. The flow divider can be circular, polygonal, or irregular in shape, preferably U-shaped, and its height is equal to the depth of the microchannel.

[0037] The microfluidic chip is preferably made of COC material, and the microchannel can be sealed by means of hot pressing or laser bonding. The sample inlet channel and the mixing channel are located on the same plane, with a small dead volume; the material inlet and the material outlet are perpendicular to the plane where the microchannel is located.

[0038] The cover plate is equipped with inlet and outlet connectors for easy connection to external devices, such as Luer-head syringe injectors and centrifuge collection tubes. When fitted with a microfluidic chip fixture, the microfluidic chip can be used for manual or automatic sample injection and collection, and is particularly suitable for medium-batch nanoparticle synthesis.

[0039] Example 2

[0040] This embodiment provides a microfluidic chip, such as Figure 3-4 As shown, the microfluidic chip includes a substrate and a cover plate. The substrate contains microchannels, including an inlet channel and a mixing channel. The cover plate has two material inlets and one material outlet. The organic phase inlet is surrounded by the aqueous phase inlet channel, and the aqueous phase inlet is vertically distributed on one side of the mixing channel. Furthermore, the two material inlets are connected to the organic phase inlet channel and the aqueous phase inlet channel, respectively, and the material outlet is connected to the mixing channel outlet.

[0041] The mixing channel is equipped with N1 series-connected mixing units, where N1 ≥ 2, preferably 4-8 units, and in this embodiment, 8 mixing units are used. The inlet of the mixing channel is the inlet of the mixing unit; the mixing unit has a polygonal structure and an internal flow-diverting structure, and in this embodiment, the mixing unit has a hexagonal "bottle spout" structure; the baffle is a concave "U" shaped structure with a semi-circular notch in the middle, the diameter of which is 1 / 2 of the baffle length; the inlet width of the mixing unit and the outlet width of the sample injection channel are both 0.2 mm, and the channel depth is 0.25 mm; in this embodiment, the baffle length is twice the outlet width, the baffle width is equal to the outlet width, and the maximum width of the mixing unit is twice the baffle length. Different outlet widths are adapted to different optimal flow rates and can be scaled up proportionally to match different sample injection flow rates.

[0042] The microfluidic chip substrate is preferably made of PDMS material, and the cover plate is preferably made of glass. The microchannels can be sealed by means of plasma bonding, etc. The sample inlet channel and the mixing channel are located on the same plane, with a small dead volume; the material inlet and the material outlet are perpendicular to the plane where the microchannels are located.

[0043] The cover plate only has through holes for inlet and outlet, and it needs to be used with a microfluidic chip fixture. It is mostly suitable for small-scale synthesis of nanoparticles in laboratory settings.

[0044] Example 3

[0045] This embodiment is a further improvement on embodiment 2. The main difference between this embodiment and embodiment 2 is that the cover plate is provided with multiple material inlets and one material outlet, so that different materials can enter the chip and participate in mixing at different positions in the microchannel.

[0046] like Figure 5 As shown, the microchannel in this embodiment still includes an inlet channel and a mixing channel. Unlike the uniform-sized design of the mixing units within the mixing channel in Embodiment 2, in this embodiment, the mixing units at different locations within the mixing channel can be scaled proportionally as the number of materials involved in the mixing increases, to adapt to the mixing requirements at different stages. Specifically, in the initial mixing stage, the number of materials involved in the mixing is small, and a smaller mixing unit is used; as new materials are added subsequently, the subsequent mixing units are enlarged proportionally to adapt to the increased material flow rate and mixing requirements.

[0047] Compared to Example 2, this example is more suitable for the continuous synthesis of multi-component nanoparticles, which is beneficial for maintaining a good mixing effect and preparation stability when the amount and flow rate of materials change at different stages.

[0048] Example 4

[0049] This embodiment provides a microchannel structure built into a microfluidic chip, such as... Figure 6 As shown, the microfluidic chip includes a substrate and a cover plate. The substrate contains microchannels, including an inlet channel and a mixing channel. The cover plate has two material inlets and one material outlet. The organic phase inlet is surrounded by the aqueous phase inlet channel, and both the aqueous and organic phase inlets are located on the extension line of the mixing channel. This design minimizes resistance within the channels and is suitable for high-flow-rate applications. Similarly, the two material inlets are connected to the organic phase inlet channel and the aqueous phase inlet channel, respectively, while the material outlet is connected to the mixing channel outlet.

[0050] The microfluidic chip substrate is preferably made of stainless steel, and the cover plate is preferably made of stainless steel. The microchannel can be sealed by threaded fastening and sealing plugs. The material inlet and material outlet are perpendicular to the plane of the microchannel. The outlet end of the sample inlet channel and the mixing channel are on the same plane. For easy sealing, part of the sample inlet channel can be located on the cover plate.

[0051] The cover plate is equipped with inlet and outlet connectors for easy connection to external devices, such as Luer-head syringe injectors and centrifuge collection tubes. The cover plate's shape can be designed with reference to microfluidic chip fixtures, allowing for direct adaptation to injection and collection devices, making it suitable for large-scale nanoparticle synthesis.

[0052] Example 5

[0053] This embodiment compares and optimizes the injection methods for materials entering the mixing unit, providing simulated concentration distributions for three injection channels flowing into a single mixing unit. For example... Figure 7 As shown, this application compares the effects of two and three inlet channels flowing into the mixing unit. Figure 7 The left side shows the concentration distribution flowing into a single mixing unit when the angle between the organic phase inlet channel and the aqueous phase inlet channel is 180°, which is described below as a "T-shaped channel". Figure 7 When the angle between the organic phase inlet channel and the aqueous phase inlet channel is 60°, the concentration distribution flowing into a single mixing unit is described below as a "Y-shaped channel". Figure 7 On the right are three injection channels. The organic phase channel and the mixing unit are in the same direction. The two aqueous phase channels are located on both sides of the organic phase channel. When the angle between the two aqueous phase channels is 180°, the concentration distribution flowing into a single mixing unit is described below as a "cross-shaped channel". From the simulation effect diagram of its concentration distribution, it can be seen that the effect of the three injection channels is significantly better than that of the two injection channels. That is, the mixing effect after the three injection channels flow into a single mixing unit is better.

[0054] Example 6

[0055] This embodiment compares and optimizes the simulated concentration distribution of three injection channels flowing into multiple mixing units. Figure 8 The schematic diagram of multiple mixing units used in the simulation shows that the entire mixing unit has a "pot spout" structure with a flow divider baffle in the middle. The baffle is a concave shape with a semi-circular notch in the middle. There are eight mixing units, connected in series at the inlet end of the mixing channel. The width of the mixing channel outlet end is half the maximum width of the mixing unit. This application also compares the final effects of three different sample inlet channels flowing through multiple mixing units, such as... Figure 9 The figure shows the concentration distribution of fluids flowing into multiple mixing units through three different inlet channels. As can be seen from the figure, the fluids after flowing through all the mixing units are essentially completely mixed.

[0056] Example 7

[0057] To optimize and quantify mixing efficiency, the mixing index MI after flowing through each mixing unit is statistically analyzed, yielding the relationship between the number of mixing units and the mixing index MI, as follows: Figure 10-12 As shown. Figure 10 This is a scatter plot of the number of mixing units through which the T-shaped injection channel flows and the mixing index MI. Figure 11 This is a scatter plot of the number of mixing units that the Y-shaped injection channel passes through and the mixing index MI. Both structures can achieve a mixing index of about 99% after passing through 8 mixing units. Figure 12 It is a scatter plot of the number of mixing units through which the cross-shaped injection channel flows and the mixing index MI. This structure can achieve the best mixing effect after flowing through 4-8 mixing units, with a mixing index as high as 99.94%.

[0058] Example 8

[0059] To optimize the effects of mixing channel outlet width, baffle length, maximum mixing unit width, and channel depth on the synthesis effect, this invention conducted simulation analysis. First, we set the maximum width of the mixing channel to 0.8 mm and performed linear sweep analysis on the mixing unit outlet width and baffle length. The final results are as follows: Figure 13-14 As shown, the mixing effect gradually decreases with increasing outlet width and baffle length of the mixing unit. Considering channel resistance and resource utilization, we conclude that when the maximum width of the mixing unit is 0.8 mm, the optimal outlet width is 0.2 mm and the optimal baffle length is 0.4 mm. Based on simulation results, we have reason to believe that there is a linear relationship between the outlet width, baffle length, and maximum width of the mixing unit, with an optimal ratio of 1:2:4. Subsequent scale-up is also based on this dimension. Then, using the above dimensions as a benchmark, we performed a dimensional scan of the channel depth, as shown in the figure. Figure 15 As shown, the mixing effect is optimal when the channel depth is 0.2 mm. When the channel depth is greater than 0.2 mm, the mixing effect tends to be stable. Therefore, the channel depth is preferably greater than or equal to the outlet width of the mixing unit.

[0060] Example 9

[0061] To explore the optimal range for the number of mixing units, we first conducted simulation analysis, concluding that the best mixing effect, with a mixing index as high as 99.94%, was achieved after flowing through 4-8 mixing units. Then, taking the microfluidic chip mentioned in Example 2 as an example, we designed its mixing unit number to be 4, keeping other dimensions unchanged. The relationship between the synthesized nanoparticle size, PDI, and flow rate is shown in the figure below. Figure 16As shown in the figure, the data indicates that when the sample flow rate is within the range of 4-12 ml / min, the liposome nanoparticles prepared by the four mixing unit structures have a particle size <80 nm and a PDI <0.20. When the sample flow rate is 8-12 ml / min, the prepared liposome nanoparticles have a particle size <50 nm and a PDI ≤0.04. Notably, at a sample flow rate of 8 ml / min, the prepared particles have the lowest PDI of 0.025. This data demonstrates the correctness of the simulation results, namely, that the microfluidic chip can achieve the best mixing effect when the number of mixing units is 4-8.

[0062] Example 10

[0063] This embodiment provides a method for synthesizing nanoparticles, which is implemented using the microfluidic chip described in the above embodiment.

[0064] This method mainly includes the following four steps: Connect the aqueous phase material and the organic phase material to the aqueous phase inlet and the organic phase inlet, respectively; Two-phase material fluids are introduced into the inlet channel at a certain flow rate ratio; The two-phase material fluids converge at the inlet of the mixing channel; Nanoparticles can be produced by sequentially passing the mixed material fluid through the mixing unit and the mixing channel outlet.

[0065] To verify the accuracy of the simulation results and the reliability of the nanoparticle synthesis method, a PDMS chip was fabricated using the structure and dimensions described in Example 2 for testing. The aqueous phase solution was a 1×PBS solution with pH 6.8, and the lipid phase solution was a mixed solution. The mixed solution was prepared by dissolving egg yolk lecithin, cholesterol, and Tween 80 in anhydrous ethanol at a concentration ratio of 5:1:1. The aqueous and lipid phases were introduced into the microfluidic chip from Example 2 at a flow rate ratio of 3:1. The collected nanoparticle products were analyzed by dynamic light scattering (DLS) using a Malvern ZS90 instrument. The relationship between the synthesized nanoparticle size, PDI, and flow rate is shown in the figure below. Figure 17 As shown in the data graph, when the total injection flow rate is 16 ml / min, the particle size of the synthesized nanoparticles is about 42 nm and the PDI is 0.071, which is close to or even exceeds most existing products on the market. As the total injection flow rate increases, the particle size and PDI decrease accordingly, indicating that there is an optimal total injection flow rate of 16 ml / min for this structural size.

[0066] Example 11

[0067] To verify whether the structure can efficiently synthesize nanoparticles after being scaled up or down proportionally, the microfluidic chip mentioned in Example 2 was used as an example, and its mixing unit was scaled up proportionally. In this example, the mixing unit structure was changed proportionally, and the outlet width of the mixing unit was used as the description object, with dimensions of 0.15 mm, 0.3 mm, and 0.6 mm added for comparison. In other channel dimensions, the channel depth was set to 0.25 mm, the sample inlet channel width was 0.5 mm, and the number of mixing units was set to 6.

[0068] When the outlet width of the mixing unit is 0.15 mm, the relationship between the synthesized nanoparticle size, PDI, and flow rate is shown in the figure below. Figure 18 As shown in the figure, liposome nanoparticles with a particle size <65nm and a PDI <0.12 can be obtained when the sample flow rate is in the range of 2-20ml / min. When the sample flow rate is in the range of 4-20ml / min, the liposome nanoparticles obtained have a particle size <60nm and a PDI <0.08. In particular, when the sample flow rate is 4ml / min, the PDI of the obtained particles is the lowest, which is 0.041.

[0069] When the outlet width of the mixing unit is 0.3 mm, the relationship between the synthesized nanoparticle size, PDI, and flow rate is shown in the figure below. Figure 19 As shown in the figure, liposome nanoparticles with a particle size <70nm and a PDI <0.10 can be obtained when the sample flow rate is in the range of 4-20ml / min. When the sample flow rate is in the range of 6-20ml / min, the obtained liposome nanoparticles have a particle size <65nm and a PDI ≤0.06. In particular, when the sample flow rate is 16ml / min, the obtained particles have the lowest PDI of 0.036.

[0070] When the outlet width of the mixing unit is 0.6 mm, the relationship between the synthesized nanoparticle size, PDI, and flow rate is shown in the figure below. Figure 20 As shown in the figure, liposome nanoparticles with a particle size <75nm and a PDI <0.17 can be obtained when the sample flow rate is in the range of 8-20ml / min. When the sample flow rate is in the range of 12-20ml / min, the liposome nanoparticles obtained have a particle size <60nm and a PDI <0.15. In particular, when the sample flow rate is 14ml / min, the PDI of the obtained particles is the lowest, at 0.070.

[0071] The data shows that satisfactory results were obtained in all four scale-up experiments of the hybrid unit structure. The synthesized nanoparticles all had a particle size of less than 100 nm, and the PDI was less than 0.07 at the appropriate flow rate. This indicates that nanoparticles can be synthesized at low to medium flow rates at this structural size, and the optimal flow rate range increases with the increase of the outlet width of the scaled-up hybrid unit.

[0072] Example 12

[0073] To expand the application scope of this invention, we take the synthesis of SM102 LNP as an example to verify the synthesis effect of this invention. The lipid phase is 12 mM SM102, with a molar ratio of SM102:DSPC (synthetic phospholipid):PEG2000-DEG (polyethylene glycol):CHOLESTEROL (cholesterol) = 50:10:1.5:38.5. The aqueous phase is a 50 mM citrate buffer solution containing 66 mM citric acid and 34 mM sodium citrate. Both phases are filtered through a 0.22 μm filter membrane, and the flow rate ratio of the organic phase to the aqueous phase is 1:3. The microfluidic chip with a mixing unit outlet width of 0.3 mm and 6 mixing units, as described in Example 8, is used for testing. The test results are as follows: Figure 21 As shown, when the sample flow rate is in the range of 4-20 ml / min, the obtained liposome nanoparticles have a particle size of <80 nm and a PDI of <0.15. When the sample flow rate is in the range of 8-20 ml / min, the obtained liposome nanoparticles have a particle size of <50 nm and a PDI of ≤0.05. This indicates that the present invention is applicable to the synthesis of SM102 LNP, and the synthesis effect is good.

[0074] Example 13

[0075] To verify the synthesis effect at high flow rates, this embodiment uses a microfluidic chip with a mixing unit outlet width of 0.8 mm and a channel depth of 0.8 mm. The mixing unit structure is proportionally varied, and the synthesis experiment is conducted at an injection flow rate of 400 ml / min. This embodiment compares the actual synthesis effects of three reagents: soybean lecithin, egg yolk lecithin, and SM102. It also compares the synthesis effects at medium-low flow rates (small-scale) and high flow rates (pilot-scale). The small-scale experiment uses a mixing chip with a mixing unit outlet width of 0.2 mm and a depth of 0.25 mm. The aqueous phase solution for the soybean lecithin reagent test is a 1×PBS solution at pH 6.8, and the lipid phase solution is a mixed solution. The mixed solution is prepared by dissolving soybean lecithin, cholesterol, and Tween 80 in anhydrous ethanol at a concentration ratio of 5:1:1. The aqueous phase solution for testing the egg yolk lecithin reagent was a 1×PBS solution at pH 6.8. The lipid phase solution was a mixed solution, prepared as follows: egg yolk lecithin, cholesterol, and Tween 80 were mixed and dissolved in anhydrous ethanol at a concentration ratio of 5:1:1. The synthesis experimental results are as follows... Figure 22As shown in the figure, in the pilot production, the synthesized particle size of soybean lecithin liposomes was less than 30 nm, and the PDI was less than 0.09; the synthesized particle size of egg yolk lecithin liposomes was less than 50 nm, and the PDI was less than 0.06; the synthesized particle size of SM102 liposomes was less than 55 nm, and the PDI was less than 0.04, demonstrating excellent synthesis results. Furthermore, there was no significant difference compared to the small-scale production.

[0076] This experimental result shows that the hybrid structure in this invention can be used to synthesize nanoparticles at low, medium and high flow rates, and can be adapted to small-scale and pilot-scale production. Through proportional scaling up of the hybrid unit, the applicable flow rate range includes, but is not limited to, 4-400 ml / min.

[0077] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0078] It should be noted that the above embodiments can be freely combined as needed. The above are merely preferred embodiments of this application. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A microfluidic chip for nanoparticle synthesis, characterized in that, Includes microchannels, wherein the microchannels include an inlet channel and a mixing channel; The sample inlet channel includes multiple material inlet channels, including at least a first material inlet channel for conveying a first material and a second material inlet channel for conveying a second material; The mixing channel is provided with at least one mixing unit, the mixing unit is defined by a boundary structure to form a fluid mixing region, and a flow splitting structure is provided within the fluid mixing region; The plurality of material inlet channels are connected to the mixing channel so that the material fluids converge in the mixing channel and are split and mixed when flowing through the at least one mixing unit, thereby forming a nanoparticle product fluid and flowing out from the mixing channel.

2. The microfluidic chip according to claim 1, characterized in that, The number of the first material inlet channels is N2, where N2 ≥ 1; When N2≥2, the outlet ends of at least two first material inlet channels are distributed on both sides of the outlet end of the second material inlet channel, and N2 first material inlet channels and the second material inlet channels are all connected to the mixing channel.

3. The microfluidic chip according to claim 2, characterized in that, The angle between the first material inlet channel and the second material inlet channel is 0° to 180°. Preferably, the first material inlet channel, the second material inlet channel, and the mixing channel form a T-shaped inlet structure, a Y-shaped inlet structure, or a cross-shaped inlet structure.

4. The microfluidic chip according to claim 1, characterized in that, The outlet width of the mixing unit, the length of the diversion structure, and the maximum width of the mixing unit satisfy a proportional relationship, preferably 1:2:4; Under the condition that the proportional relationship remains unchanged, the mixing unit and its internal flow splitting structure can be scaled up or down proportionally to adapt to different total injection flow rates.

5. The microfluidic chip according to claim 4, characterized in that, At least some of the multiple material inlet channels are connected to the mixing channel at different positions along the fluid flow direction, so that different materials enter and participate in mixing at different stages of the mixing channel, and the mixing units at different positions in the mixing channel are scaled proportionally as a whole according to the mixing requirements of the corresponding stage.

6. The microfluidic chip according to claim 1, characterized in that, The hybrid unit can be any one of a circle, a polygon, or an irregular shape, preferably a hexagonal structure; The diversion structure is a circle, polygon, or irregular shape, preferably a concave shape.

7. The microfluidic chip according to claim 1, characterized in that, The mixing unit, the mixing channel, and the sample inlet channel are all or partially disposed in the same plane; and / or, The height of the diversion structure is less than or equal to the depth of the mixing unit, and the depth of the mixing unit is greater than or equal to the outlet width of the mixing unit.

8. The microfluidic chip according to claim 1, characterized in that, The microfluidic chip also includes: Multiple material inlets are connected to the upstream of the multiple material injection channels, respectively; A material outlet is connected downstream of the mixing channel.

9. The microfluidic chip according to claim 8, characterized in that, The microfluidic chip also includes a substrate and a cover plate, wherein the microchannel, material inlet and material outlet are respectively independently disposed on the substrate and / or the cover plate; The substrate and cover plate are sealed together, preferably by means of hot pressing, laser bonding, plasma bonding or threaded fastening of the sealing element. Preferably, the substrate and the cover plate are made of one or more materials selected independently from PDMS, glass, COC and stainless steel.

10. A method for synthesizing nanoparticles, characterized in that, The microfluidic chip according to any one of claims 1 to 9 comprises the following steps: Each material to be mixed is introduced into its corresponding material inlet channel according to a preset flow rate ratio; The materials are introduced into the mixing channel through the material inlet channel and then merged. The materials that have merged are then passed through the mixing unit in the mixing channel, where they are separated and mixed. The nanoparticle product fluid collected from the microfluidic chip.

Images