Microfluidic channel structure and microfluidic chip comprising same

Abstract

The present application provides a microfluidic channel structure and a microfluidic chip comprising same. The microfluidic channel structure comprises a plurality of liquid inlet channels arranged in parallel and a front-end main channel; one end of each of the plurality of liquid inlet channels is used for liquid feed; and the other ends of the plurality of liquid inlet channels converge and are communicated with the front-end main channel. The microfluidic channel structure further comprises a mixing channel consisting of a plurality of Ω-shaped structure channels connected in sequence; one end of the mixing channel is communicated with the end of the front-end main channel away from the liquid inlet channels; the other end of the mixing channel is communicated with a liquid outlet channel; and the cross-sectional area of the front-end main channel is not greater than that of the single liquid inlet channel. The mixing channel uses the Ω-shaped structure channels, so that when fluid passes through each of bends of the Ω-shaped structure channels, a shear force can be generated due to the velocity difference between fluid layers, enhancing the interaction between different fluid layers; the bent portions of the Ω-shaped structure channels form vortexes, further breaking the layering of the fluid, promoting mixing, and helping to improve mixing efficiency.

Description

Microchannel structures and microfluidic chips containing them

[0001] This application claims priority to Chinese patent application 2024232053209, filed on 2024 / 12 / 24. The entire contents of the aforementioned Chinese patent application are incorporated herein by reference. Technical Field

[0002] This application specifically relates to a microchannel structure and a microfluidic chip containing the same. Background Technology

[0003] Microfluidics is a novel precision particle manufacturing technology that leverages the unique fluid properties of a microscale environment to perform a series of microfabrication and micromanipulation processes that are difficult to achieve using conventional methods, thereby producing micro / nanoparticles with uniform structure and size. Currently, this technology has been applied to research on a range of micro / nanoparticle drug delivery systems, including liposomes, nanocrystals, nanoparticles, and microspheres. A core component of microfluidics is the microfluidic chip; by designing the channels of the microfluidic chip, nanoparticles of various sizes can be fabricated at different rates.

[0004] The size of nanoparticles affects their biodistribution, cellular uptake, clearance from plasma and interstitial spaces, and excretion in vivo. Generally, particles smaller than 100 nm can penetrate biological membranes more effectively and enter cells, while larger particles may be recognized and cleared by the immune system. Therefore, for nanoparticle drug delivery systems to achieve good results, precise control of nanoparticle size is essential. While existing microfluidic chips can prepare nanoparticles smaller than 100 nm, to achieve higher particle size uniformity and keep the PDI (aggregation index, a parameter describing the uniformity of particle size distribution) within a small range, the feed flow rate is controlled. This limits the ability to meet the demands for rapid, large-scale preparation. Summary of the Invention

[0005] The technical problem to be solved by this application is to overcome the defects of narrow tolerable flow rate range and low preparation efficiency in the preparation of nanoparticles with a size of less than 100nm in the prior art. The application provides a microchannel structure that can efficiently prepare nanoparticles and a microfluidic chip containing the structure.

[0006] This application solves the above-mentioned technical problems through the following technical solution:

[0007] A microfluidic structure includes multiple parallel liquid inlet channels and a front-end main channel. One end of the multiple liquid inlet channels is used for liquid inlet, and the other ends of the multiple liquid inlet channels converge and communicate with the front-end main channel.

[0008] The microfluidic structure also includes a mixing channel composed of several sequentially connected Ω-shaped structural channels. One end of the mixing channel is connected to the end of the front main channel away from the liquid inlet channel, and the other end of the mixing channel is connected to the liquid outlet channel. The cross-sectional area of ​​the front main channel is not greater than the cross-sectional area of ​​a single liquid inlet channel.

[0009] In one alternative implementation, the number of Ω-shaped channel channels is 1-100, preferably 1-30, and more preferably 1-10.

[0010] In one optional embodiment, the plurality of liquid inlet channels form an angle at the junction, wherein the angle between two liquid inlet channels is 0°-180°, preferably 45°-180°, and more preferably 60°-180°.

[0011] In one optional embodiment, the Ω-shaped structure channel includes a first arc-shaped channel and two second arc-shaped channels connected to both ends of the first arc-shaped channel, with the centers of the two second arc-shaped channels located on both sides of the Ω-shaped structure channel.

[0012] In one alternative implementation, two adjacent Ω-shaped channel structures are arranged in a centrally symmetrical or axisymmetric manner.

[0013] In one alternative implementation, two adjacent Ω-shaped channel structures are connected by a horizontal transition section.

[0014] In one alternative implementation, the microchannel structure is configured to satisfy at least one of the following configurations:

[0015] (1) The radius of curvature of the second arc-shaped channel is 100-3000μm, preferably 200-2000μm, and more preferably 300-1500μm;

[0016] (2) The radius of curvature of the first arc-shaped channel is 100-3000μm, preferably 200-2000μm, and more preferably 400-1800μm;

[0017] (3) The channel width of the mixing channel is 10-1500μm, preferably 100-1000μm, and more preferably 100-800μm;

[0018] (4) The channel depth of the hybrid channel is 10-1500μm, preferably 100-1000μm, and more preferably 100-800μm;

[0019] (5) The horizontal distance between the centers of the first arc-shaped channels of two adjacent Ω-shaped structural channels is 200-10000μm, preferably 500-8000μm, and more preferably 1000-6000μm.

[0020] (6) The central angle α formed by connecting the center of the first arc-shaped channel with the centers of the two second arc-shaped channels is in the range of 4°-180°, preferably 60°-120°, and more preferably 60°-100°.

[0021] In one optional embodiment, the ratio of the minimum cross-sectional area of ​​the liquid inlet channel to the cross-sectional area of ​​the front main channel is (1-5):1, preferably (1-3):1, and more preferably (1-2):1.

[0022] In one alternative implementation, the microchannel structure is configured to satisfy at least one of the following configurations:

[0023] (1) The width of the liquid inlet channel is 10-1000μm, preferably 50-900μm, and more preferably 100-800μm;

[0024] (2) The depth of the liquid inlet channel is 10-1000μm, preferably 100-900μm, and more preferably 100-800μm;

[0025] (3) The length of the liquid inlet channel is 10-40 mm, preferably 15-30 mm, and more preferably 18-28 mm;

[0026] (4) The width of the front-end main channel is 10-1000μm, preferably 50-800μm, and more preferably 100-600μm;

[0027] (5) The depth of the front-end main channel is 10-1000μm, preferably 50-800μm, and more preferably 100-800μm;

[0028] (6) The length of the front-end main channel is 100-5000μm, preferably 200-4000μm, and more preferably 400-3000μm.

[0029] In one optional embodiment, the width of the liquid outlet channel is 10-1000 μm, preferably 50-900 μm, and more preferably 100-800 μm;

[0030] And / or, the depth of the liquid outlet channel is 10-1000 μm, preferably 100-900 μm, and more preferably 100-800 μm;

[0031] And / or, the length of the liquid outlet channel is 0.01-10cm, preferably 0.1-5cm, and more preferably 0.3-3cm.

[0032] In one optional embodiment, the end of the liquid outlet channel connected to the mixing channel is straight, and the end of the liquid outlet channel away from the mixing channel is curved.

[0033] The ratio of the length of the straight liquid outlet channel to the arc length of the curved liquid outlet channel is (0.1-5):1, more preferably (0.3-3):1, and even more preferably (0.5-2):1;

[0034] And / or, the angle between the axis of the straight liquid outlet channel and the tangent of the outer edge of the curved liquid outlet channel is 0° to 90°, preferably 10° to 80°, and more preferably 20° to 60°.

[0035] In one alternative implementation, the liquid outlet channel may be either straight or curved.

[0036] This application also provides a microfluidic chip, the microfluidic chip including a substrate, on which a microchannel structure as described above is provided.

[0037] Preferably, the microfluidic chip includes a cover plate disposed on the side of the substrate having the microfluidic channel structure, and the cover plate has an inlet and an outlet.

[0038] Preferably, the materials of the cover plate and the substrate can be commonly used microfluidic chip materials, such as one or more of metal, glass, quartz, ceramic, silicon, Hastelloy, or polymers. The metal can be stainless steel; the polymer can be polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), polypropylene (PP), polyethylene (PE), polyamide (PI), polydimethylsiloxane (PDMS), polyterephthalic acid (PET), polyvinyl chloride (PVC), photoresist, polyester (TPE), polyethylene glycol diacrylate (PEGDA), perfluorinated compounds, polyurethane (PU), cyclic olefin copolymers (COC), and cyclic olefin polymers (COP). The photoresist can be SU-8 photoresist, and the perfluorinated compound can be one or more of perfluoroethylene propylene (PFEP), perfluoroalkoxy (PFA), and perfluoropolyether (PFPE).

[0039] Preferably, the number of microchannel structures on each microfluidic chip can be one or more.

[0040] In some preferred embodiments, the number of microchannel structures on each microfluidic chip is two or more, and the microchannel structures adopt a staggered design, which can not only achieve efficient use of space, but also reduce the cost of microfluidic chips and improve utilization.

[0041] In practical applications, multiple microfluidic chips can be integrated and used in series and / or parallel, depending on the application and batch requirements.

[0042] The positive and progressive effects of this application are as follows:

[0043] (1) In this application, the mixing channel adopts an Ω-shaped structure channel, so that the mixing of fluids mainly depends on the interaction of shearing and flow stratification. When the fluid passes through each bend of the Ω-shaped structure channel, the velocity difference between the fluid layers will generate shear force, which enhances the interaction between different fluid layers. At the same time, the bend of the Ω-shaped structure channel forms vortices, which further breaks the stratification of the fluid and promotes mixing. In addition, the complex flow path and long residence time of the Ω-shaped channel also help to improve the mixing efficiency.

[0044] By setting multiple Ω-shaped channels in the mixing channel, the fluid can circulate continuously within the mixing channel, reducing dead zones and stagnant areas. Furthermore, the fluid direction changes continuously as it flows through the Ω-shaped channels, which helps to improve mixing efficiency.

[0045] (2) In this application, the cross-sectional area of ​​the front main channel is set to be no greater than the cross-sectional area of ​​a single liquid inlet channel, so that the fluid velocity increases when it enters the front main channel from the liquid inlet channel, thereby increasing the speed at which the fluid enters the mixing channel and greatly improving the mixing efficiency of the fluid. Attached Figure Description

[0046] Figure 1 is a schematic diagram of the microchannel structure of this application.

[0047] Figure 2 is a schematic diagram of the Ω-shaped channel in Figure 1.

[0048] Figure 3 is a schematic diagram showing the positions of two adjacent Ω-shaped structural channels in Figure 1.

[0049] Figure 4 is a schematic diagram of the microchannel structure distribution on a microfluidic chip in this application.

[0050] Figure 5 shows the size of lipid nanoparticles and PDI data determined by dynamic light scattering in Example 2.

[0051] Explanation of reference numerals in the attached drawings: Liquid inlet channel 100, front-end main channel 200, mixing channel 300, Ω-shaped structure channel 310, first arc-shaped channel 311, second arc-shaped channel 312, liquid outlet channel 400, liquid inlet 500, liquid outlet 600, substrate 700. Detailed Implementation

[0052] The following preferred embodiment, together with the accompanying drawings, will provide a clearer and more complete description of this application.

[0053] Referring to Figures 1-4, this is a schematic diagram of the microfluidic channel structure of the microfluidic chip of this application. This application includes multiple parallel-connected inlet channels 100 and a front-end main channel 200. One end of each inlet channel 100 is used for liquid inlet, and the other ends of the multiple inlet channels 100 converge and communicate with the front-end main channel 200. The microfluidic structure also includes a mixing channel 300 composed of several sequentially connected Ω-shaped structural channels 310. One end of the mixing channel 300 is connected to the end of the front-end main channel 200 away from the inlet channel 100, and the other end of the mixing channel 300 is connected to an outlet channel 400. The cross-sectional area of ​​the front-end main channel 200 is no larger than the cross-sectional area of ​​a single inlet channel 100. Adjacent Ω-shaped structural channels 310 are arranged centrally symmetrically. Each inlet channel 100 has an inlet 500 at its front end and an outlet 600 at its end. Adjacent Ω-shaped structural channels are connected by a horizontal transition section.

[0054] The number of Ω-shaped channel 310 is 1-100, preferably 1-30, and even more preferably 1-10.

[0055] Multiple liquid inlet channels form an angle at the confluence point. The angle between two liquid inlet channels is 0°-180°, preferably 45°-180°, and more preferably 60°-180°.

[0056] The Ω-shaped structure channel 310 includes a first arc-shaped channel 311 and two second arc-shaped channels 312 connected to both ends of the first arc-shaped channel 311. The centers of the two second arc-shaped channels 312 are located on both sides of the Ω-shaped structure channel 310.

[0057] The radius of curvature of the second arc-shaped channel 312 is 100-3000μm, preferably 200-2000μm, and more preferably 300-1500μm;

[0058] And / or, the radius of curvature of the first arc-shaped channel 311 is 100-3000 μm, preferably 200-2000 μm, and more preferably 300-1500 μm;

[0059] And / or, the channel width of the mixing channel 300 is 10-1500 μm, preferably 100-1000 μm, and more preferably 100-800 μm;

[0060] And / or, the channel depth of the hybrid channel 300 is 10-1500 μm, preferably 100-1000 μm, and more preferably 100-800 μm;

[0061] And / or, the horizontal distance L between the centers of the first arc-shaped channels 311 of two adjacent Ω-shaped structural channels 310 is 200-10000μm, preferably 500-8000μm, and more preferably 1000-6000μm.

[0062] And / or, the central angle α formed by connecting the center of the first arc-shaped channel with the centers of the two second arc-shaped channels ranges from 4° to 180°, preferably from 60° to 120°, and more preferably from 60° to 100°.

[0063] The ratio of the minimum cross-sectional area of ​​the liquid inlet channel to the cross-sectional area of ​​the front main channel 200 is (1-5):1, preferably (1-3):1, and more preferably (1-2):1.

[0064] The width of the liquid inlet channel is 10-1000μm, preferably 50-900μm, and more preferably 100-800μm;

[0065] And / or, the depth of the liquid inlet channel is 10-1000 μm, preferably 100-900 μm, and more preferably 100-800 μm;

[0066] And / or, the length of the liquid inlet channel is 10-40 mm, preferably 15-30 mm, and more preferably 18-28 mm;

[0067] And / or, the width of the front-end main channel 200 is 10-1000μm, preferably 50-800μm, and more preferably 100-600μm;

[0068] And / or, the depth of the front-end main channel 200 is 10-1000μm, preferably 50-800μm, and more preferably 100-800μm;

[0069] And / or, the length of the front-end main channel 200 is 100-5000μm, preferably 200-4000μm, and more preferably 400-3000μm.

[0070] The width of the liquid outlet channel 400 is 10-1000μm, preferably 50-900μm, and more preferably 100-800μm;

[0071] And / or, the depth of the liquid outlet channel 400 is 10-1000 μm, preferably 100-900 μm, and more preferably 100-800 μm;

[0072] And / or, the length of the liquid outlet channel 400 is 0.01-10cm, preferably 0.1-5cm, and more preferably 0.3-3cm.

[0073] The end of the liquid outlet channel 400 connected to the mixing channel 300 is straight, and the end of the liquid outlet channel 400 away from the mixing channel 300 is curved; the ratio of the length of the straight liquid outlet channel 400 to the arc length of the curved liquid outlet channel 400 is (0.1~5)∶1, preferably (0.3~3)∶1, and more preferably (0.5~2)∶1.

[0074] The angle between the axis of the straight liquid outlet channel 400 and the tangent of the outer edge of the curved liquid outlet channel 400 is 0° to 90°, preferably 10° to 80°, and more preferably 20° to 60°.

[0075] In one alternative implementation, the liquid outlet channel 400 may be either straight or curved.

[0076] This application also discloses a microfluidic chip, which includes a substrate 700 on which the microchannel structure described above is provided.

[0077] The microfluidic chip also includes a cover plate, which is located on one side of the substrate 700 with a microchannel structure. The cover plate has an inlet 500 and an outlet 600.

[0078] The cover plate and substrate 700 can be made of commonly used microfluidic chip materials, such as one or more of metal, glass, quartz, ceramic, silicon, Hastelloy, or polymers. The metal can be stainless steel; the polymer can be polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), polypropylene (PP), polyethylene (PE), polyamide (PI), polydimethylsiloxane (PDMS), polyterephthalic acid (PET), polyvinyl chloride (PVC), photoresist, polyester (TPE), polyethylene glycol diacrylate (PEGDA), perfluorinated compounds, polyurethane (PU), cyclic olefin copolymers (COC), and cyclic olefin polymers (COP). The photoresist can be SU-8 photoresist, and the perfluorinated compound can be one or more of perfluoroethylene propylene (PFEP), perfluoroalkoxy (PFA), and perfluoropolyether (PFPE).

[0079] The number of microchannel structures on each microfluidic chip can be one or more.

[0080] In some implementations, the number of microchannel structures on each microfluidic chip is two or more, as shown in Figure 4. The microchannel structures adopt a staggered design, which can not only achieve effective use of space, but also reduce the cost of microfluidic chips and improve utilization.

[0081] In practical applications, multiple microfluidic chips can be integrated and used in series and / or parallel, depending on the application and batch requirements.

[0082] Example 1

[0083] In this embodiment, the microfluidic chip has two liquid inlet channels 100 in its microfluidic structure. The angle formed by the two liquid inlet channels at their intersection is 60°. The central angle α formed by connecting the center of the first arc-shaped channel with the centers of the two second arc-shaped channels is 90°. The mixing channel 300 is composed of six Ω-shaped channel 310s. Two adjacent Ω-shaped channel 310s are centrally symmetrical. The end of the liquid outlet channel 400 connected to the mixing channel 300 is straight, and the end of the liquid outlet channel 400 away from the mixing channel 300 is curved. The second arc-shaped channel has a radius of curvature of 500 μm; the first arc-shaped channel has a radius of curvature of 600 μm; the mixing channel has a width of 200 μm; the mixing channel has a depth of 300 μm; the horizontal distance between the centers of the first arc-shaped channels of two adjacent Ω-shaped structure channels is 2000 μm; the liquid inlet channel has a width of 300 μm; the liquid inlet channel has a depth of 300 μm; the liquid inlet channel has a length of 20 mm; the front main channel has a width of 200 μm; the front main channel has a depth of 300 μm; and the front main channel has a length of 1000 μm.

[0084] To test the performance of the microfluidic chip in this application, lipid nanoparticles were prepared using the following method:

[0085] (1) DLin-MC3-DMA (1,2-dilinoleyloxy-3-dimethylaminopropane), DSPC (distearate phosphatidylcholine), cholesterol, and DMG-PEG2000 (1,2-dimyristoyl-rac-glycerol-3-methoxy polyethylene glycol 2000) were prepared into an ethanol solution with a total concentration of 10 mM as the organic phase, and a 50 mM citrate buffer solution with a pH of 4.0 was used as the aqueous phase.

[0086] (2) The above organic phase and aqueous phase were injected into the microfluidic chip through an injection pump at flow rates of 1:1, 1:2, 1:3, 1:4, 1:5, and 1:6, with a total flow rate of 12 mL / min, to prepare lipid nanoparticle solutions.

[0087] (3) After dialysis of the above lipid nanoparticle solution in PBS buffer overnight, lipid nanoparticles are obtained.

[0088] (4) The size and PDI of lipid nanoparticles were determined by dynamic light scattering method. The results are listed in Table 1.

[0089] Table 1

[0090] The results in the table above show that when the flow rate ratio is 1:1, the average particle size of the lipid nanoparticles is relatively large, which is 711 nm ± 15 nm. When the flow rate ratio is between 1:2 and 1:6, the average particle size of the lipid nanoparticles is less than 100 nm, and the PDI is less than 0.15, indicating a small particle size distribution. This shows that the microfluidic chip of this application can prepare lipid nanoparticles with small particle size and uniform size at flow rates of 1:2 to 1:6 between the organic phase and the aqueous phase.

[0091] Example 2

[0092] In this embodiment, the microfluidic chip has two liquid inlet channels 100 in its microfluidic structure. The angle formed by the two liquid inlet channels at their intersection is 60°. The central angle α formed by connecting the center of the first arc-shaped channel with the centers of the two second arc-shaped channels is 90°. The mixing channel 300 is composed of six Ω-shaped channel 310s. Two adjacent Ω-shaped channel 310s are centrally symmetrical. The end of the liquid outlet channel 400 connected to the mixing channel 300 is straight, and the end of the liquid outlet channel 400 away from the mixing channel 300 is curved. The radius of curvature of the second arc-shaped channel is 2000 μm; the radius of curvature of the first arc-shaped channel is 2400 μm; the width of the mixing channel is 800 μm; the depth of the mixing channel is 600 μm; the horizontal distance between the centers of the first arc-shaped channels of two adjacent Ω-shaped structure channels is 6500 μm; the width of the liquid inlet channel is 800 μm; the depth of the liquid inlet channel is 600 μm; the length of the liquid inlet channel is 6 mm; the width of the front main channel is 600 μm; the depth of the front main channel is 600 μm; the length of the front main channel is 1000 μm.

[0093] To test the tolerable flow rate range of the microfluidic chip of this application, lipid nanoparticles were prepared using the following method:

[0094] (1) Prepare an ethanol solution with a total concentration of 10 mM by mixing DLin-MC3-DMA, DSPC, cholesterol, and DMG-PEG2000 in a molar ratio of 46.3:9.4:42.7:1.6 as the organic phase, and use a 50 mM citrate buffer solution with a pH of 4.0 as the aqueous phase.

[0095] (2) The above organic phase and aqueous phase are injected into the microfluidic chip at a flow rate ratio of 1:3 and a total flow rate of 2 mL / min to 100 mL / min respectively through an injection pump to prepare a lipid nanoparticle solution.

[0096] (3) The size and PDI of lipid nanoparticles were determined by dynamic light scattering method. The results are shown in Figure 5.

[0097] As shown in Figure 5, when the total flow rate is 4 mL / min to 100 mL / min, the average particle size of the lipid nanoparticles prepared by the microfluidic chip of this application is less than 100 nm, and the PDI is less than 0.15. This indicates that the applicable flow rate range of this chip is at least 4 mL / min to 100 mL / min.

[0098] Examples 3-5

[0099] In Examples 3-5, the microfluidic chip has two liquid inlet channels 100 in its microfluidic structure. The angle formed by the two liquid inlet channels at their intersection is 60°. The central angle α formed by connecting the center of the first arc-shaped channel with the centers of the two second arc-shaped channels is 90°. The mixing channel 300 is composed of six Ω-shaped channel 310s. Two adjacent Ω-shaped channel 310s are centrally symmetrical. The end of the liquid outlet channel 400 connected to the mixing channel 300 is straight, and the end of the liquid outlet channel 400 away from the mixing channel 300 is curved. The second arc-shaped channel has a radius of curvature of 500 μm; the first arc-shaped channel has a radius of curvature of 600 μm; the mixing channel has a width of 200 μm; the mixing channel has a depth of 300 μm; the horizontal distance between the centers of the first arc-shaped channels of two adjacent Ω-shaped structure channels is 2000 μm; the liquid inlet channel has a depth of 300 μm; the liquid inlet channel has a length of 20 mm; the front main channel has a width of 200 μm; the front main channel has a depth of 300 μm; and the front main channel has a length of 1000 μm. Specifically, in Example 3, the width of the liquid inlet channel is 200 μm; in Example 4, the width of the liquid inlet channel is 300 μm; and in Example 5, the width of the liquid inlet channel is 600 μm.

[0100] To investigate the effect of the width of the liquid inlet channel of the microfluidic chip in this application on mixing, lipid nanoparticles were prepared using the following method:

[0101] (1) Prepare an ethanol solution with a total concentration of 10 mM by mixing DLin-MC3-DMA, DSPC, cholesterol, and DMG-PEG2000 in a molar ratio of 46.3:9.4:42.7:1.6 as the organic phase, and use a 50 mM citrate buffer solution with a pH of 4.0 as the aqueous phase.

[0102] (2) The above organic phase and aqueous phase were injected into the microfluidic chip through an injection pump at a flow rate ratio of 1:3 and a total flow rate of 12 mL / min to obtain a lipid nanoparticle solution.

[0103] The width of the liquid inlet channel in the microfluidic chip used in Example 3 is 200 μm;

[0104] The width of the liquid inlet channel in the microfluidic chip used in Example 4 is 300 μm;

[0105] The width of the liquid inlet channel in the microfluidic chip used in Example 5 is 600 μm.

[0106] (3) After dialysis of the above lipid nanoparticle solution in PBS buffer overnight, lipid nanoparticles are obtained.

[0107] (4) The size and PDI of lipid nanoparticles were determined by dynamic light scattering method. The results are listed in Table 3.

[0108] Table 2

[0109] As can be seen from the results in the table above, the average particle size of the lipid nanoparticles prepared in Example 3 is about 65 nm and the PDI is about 0.15. In contrast, the average particle size of the lipid nanoparticles prepared in Examples 4-5 is all below 60 nm and the PDI is all less than 0.15, indicating that the lipid nanoparticles prepared in Examples 4-5 have smaller and more uniform particle sizes.

[0110] Examples 6-8

[0111] In this embodiment, the microfluidic chip has two liquid inlet channels 100 in its microfluidic structure. The angle formed by the two liquid inlet channels at their intersection is 60°. The central angle α formed by connecting the center of the first arc-shaped channel with the centers of the two second arc-shaped channels is 90°. The mixing channel 300 is composed of six Ω-shaped channel 310s. Two adjacent Ω-shaped channel 310s are centrally symmetrical. The end of the liquid outlet channel 400 connected to the mixing channel 300 is straight, and the end of the liquid outlet channel 400 away from the mixing channel 300 is curved.

[0112] In Example 6: the radius of curvature of the second arc-shaped channel is 450 μm; the radius of curvature of the first arc-shaped channel is 550 μm; the width of the mixing channel is 100 μm; the depth of the mixing channel is 300 μm; the horizontal distance between the centers of the first arc-shaped channels of two adjacent Ω-shaped structure channels is 2000 μm; the width of the liquid inlet channel is 300 μm; the depth of the liquid inlet channel is 300 μm; the length of the liquid inlet channel is 20 mm; the width of the front main channel is 200 μm; the depth of the front main channel is 300 μm; and the length of the front main channel is 1000 μm.

[0113] In Example 7: the radius of curvature of the second arc-shaped channel is 500 μm; the radius of curvature of the first arc-shaped channel is 600 μm; the width of the mixing channel is 200 μm; the depth of the mixing channel is 300 μm; the horizontal distance between the centers of the first arc-shaped channels of two adjacent Ω-shaped structure channels is 2000 μm; the width of the liquid inlet channel is 300 μm; the depth of the liquid inlet channel is 300 μm; the length of the liquid inlet channel is 20 mm; the width of the front main channel is 200 μm; the depth of the front main channel is 300 μm; and the length of the front main channel is 1000 μm.

[0114] In Example 8: the radius of curvature of the second arc-shaped channel is 2000 μm; the radius of curvature of the first arc-shaped channel is 2400 μm; the width of the mixing channel is 800 μm; the depth of the mixing channel is 600 μm; the horizontal distance between the centers of the first arc-shaped channels of two adjacent Ω-shaped structure channels is 6500 μm; the width of the liquid inlet channel is 800 μm; the depth of the liquid inlet channel is 600 μm; the length of the liquid inlet channel is 6 mm; the width of the front main channel is 600 μm; the depth of the front main channel is 600 μm; and the length of the front main channel is 1000 μm.

[0115] To investigate the effect of the 300mm width of the mixing channel in the microfluidic structure of this application on mixing, lipid nanoparticles were prepared using the following method:

[0116] (1) Prepare an ethanol solution with a total concentration of 10 mM by mixing DLin-MC3-DMA, DSPC, cholesterol, and DMG-PEG2000 in a molar ratio of 46.3:9.4:42.7:1.6 as the organic phase, and use a 50 mM citrate buffer solution with a pH of 4.0 as the aqueous phase.

[0117] (2) The above organic phase and aqueous phase were injected into the microfluidic chip through an injection pump at a flow rate ratio of 1:3 and a total flow rate of 12 mL / min to obtain a lipid nanoparticle solution.

[0118] The width of the Ω-shaped microchannel in the microfluidic chip used in Example 6 is 100 μm;

[0119] The width of the Ω-shaped microchannel in the microfluidic chip used in Example 7 is 200 μm;

[0120] The width of the Ω-shaped microchannel in the microfluidic chip used in Example 8 is 800 μm.

[0121] (3) The above lipid nanoparticle solution was dialyzed overnight in PBS buffer to obtain lipid nanoparticles.

[0122] (4) The size and PDI of lipid nanoparticles were determined by dynamic light scattering method. The results are listed in Table 3.

[0123] Table 3

[0124] The results in the table above show that the average particle size of the lipid nanoparticles prepared in Examples 6-8 is below 100 nm, and the PDI is less than 0.15, indicating that the particles in Examples 6-8 have good uniformity. Based on these results, when the width of the mixing channel 300 is increased from 100 μm to 800 μm, the particle size of the prepared lipid nanoparticles is basically consistent.

[0125] Example 9

[0126] To examine whether the microfluidic chip of this application has the ability to stably produce lipid nanoparticles loaded with siRNA, lipid nanoparticles loaded with siRNA were prepared using the following method, and the process was repeated multiple times:

[0127] (1) Prepare an ethanol solution with a total concentration of 10 mM by mixing DLin-MC3-DMA, DSPC, cholesterol, and DMG-PEG2000 in a molar ratio of 46.3:9.4:42.7:1.6 as the organic phase, and add a certain amount of siRNA to a 50 mM citrate buffer solution with a pH of 4.0 (N:P ratio of 6) as the aqueous phase.

[0128] (2) The above organic phase and aqueous phase were injected into the microfluidic chip through an injection pump at a flow rate ratio of 1:3 and a total flow rate of 12 mL / min to obtain a lipid nanoparticle solution.

[0129] (3) After dialysis of the above lipid nanoparticle solution in PBS buffer overnight, lipid nanoparticles are obtained.

[0130] (4) The size and PDI of lipid nanoparticles were determined by dynamic light scattering method, and the encapsulation efficiency of lipid nanoparticles was determined by Quant iTRiboGreen RNA quantification kit. The results are listed in Table 4.

[0131] Table 4

[0132] As shown in the table above, the average particle size of the lipid nanoparticles loaded with siRNA prepared by the microfluidic chip based on this microchannel structure is around 60 nm, the PDI is less than 0.15, and the encapsulation efficiency of siRNA is above 85%. This indicates that the microfluidic chip based on this microchannel structure has the ability to repeatedly produce lipid nanoparticles with small and uniform particle size and high encapsulation efficiency.

[0133] While specific embodiments of this application have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this application, but all such changes and modifications fall within the scope of protection of this application.

Claims

1. A microchannel structure, characterized in that, The microchannel structure includes multiple parallel liquid inlet channels and a front-end main channel. One end of the multiple liquid inlet channels is used for liquid inlet, and the other ends of the multiple liquid inlet channels converge and communicate with the front-end main channel. The microfluidic structure also includes a mixing channel composed of several sequentially connected Ω-shaped structural channels. One end of the mixing channel is connected to the end of the front main channel away from the liquid inlet channel, and the other end of the mixing channel is connected to the liquid outlet channel. The cross-sectional area of ​​the front main channel is not greater than the cross-sectional area of ​​a single liquid inlet channel.

2. The microchannel structure as described in claim 1, characterized in that, The Ω-shaped structure channel includes a first arc-shaped channel and two second arc-shaped channels connected to both ends of the first arc-shaped channel, with the centers of the two second arc-shaped channels located on both sides of the Ω-shaped structure channel, respectively. And / or, two adjacent Ω-shaped structural channels are arranged in a centrally symmetrical or axisymmetric manner; And / or, two adjacent Ω-shaped channel structures are connected by a horizontal transition section.

3. The microchannel structure as described in claim 2, characterized in that, The microchannel structure is configured to satisfy at least one of the following configurations: (1) The radius of curvature of the second arc-shaped channel is 100-3000μm; (2) The radius of curvature of the first arc-shaped channel is 100-3000μm; (3) The channel width of the mixing channel is 10-1500μm; (4) The channel depth of the mixing channel is 10-1500 μm; (5) The horizontal distance between the centers of the first arc-shaped channels of two adjacent Ω-shaped structural channels is 200-10000μm; (6) The central angle α formed by connecting the center of the first arc-shaped channel with the centers of the two second arc-shaped channels ranges from 4° to 180°.

4. The microchannel structure as described in claim 3, characterized in that, The microchannel structure is configured to satisfy at least one of the following configurations: (1) The radius of curvature of the second arc-shaped channel is 300-1500μm; (2) The radius of curvature of the first arc-shaped channel is 400-1800μm; (3) The channel width of the mixing channel is 100-800μm; (4) The channel depth of the mixing channel is 100-800 μm; (5) The horizontal distance between the centers of the first arc-shaped channels of two adjacent Ω-shaped structural channels is 1000-6000μm; (6) The central angle α formed by connecting the center of the first arc-shaped channel with the centers of the two second arc-shaped channels is in the range of 60°-100°.

5. The microchannel structure according to any one of claims 1-4, characterized in that, The ratio of the minimum cross-sectional area of ​​the liquid inlet channel to the cross-sectional area of ​​the front main channel is (1-5):

1.

6. The microchannel structure according to any one of claims 1-5, characterized in that, The microchannel structure is configured to satisfy at least one of the following configurations: (1) The width of the liquid inlet channel is 10-1000μm; (2) The depth of the liquid inlet channel is 10-1000μm; (3) The length of the liquid inlet channel is 10-40 mm; (4) The width of the front-end main channel is 10-1000μm; (5) The depth of the front-end main channel is 10-1000μm; (6) The length of the front-end main channel is 100-5000μm.

7. The microchannel structure as described in claim 6, characterized in that, The microchannel structure is configured to satisfy at least one of the following configurations: (1) The width of the liquid inlet channel is 100-800μm; (2) The depth of the liquid inlet channel is 100-800μm; (3) The length of the liquid inlet channel is 18-28 mm; (4) The width of the front-end main channel is 100-600μm; (5) The depth of the front-end main channel is 100-800μm; (6) The length of the front-end main channel is 400-3000μm.

8. The microchannel structure according to any one of claims 1-7, characterized in that, The width of the liquid outlet channel is 10-1000 μm; And / or, the depth of the liquid outlet channel is 10-1000 μm; And / or, the length of the liquid outlet channel is 0.01-10cm.

9. The microchannel structure according to any one of claims 1-8, characterized in that, The end of the liquid outlet channel connected to the mixing channel is straight, and the end of the liquid outlet channel away from the mixing channel is curved. The ratio of the length of the straight liquid outlet channel to the arc length of the curved liquid outlet channel is (0.1~5)∶1; And / or, the angle between the axis of the straight liquid outlet channel and the tangent of the outer edge of the curved liquid outlet channel is 0 to 90°.

10. A microfluidic chip, characterized in that, The microfluidic chip includes a substrate, on which a microchannel structure as described in any one of claims 1-9 is provided.

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