A dialysis type microfluidic mixing device and a method for in-situ preparation and purification of liposomes

Abstract

The application provides a dialysis type micro-fluidic mixing device and a method for preparing and purifying liposomes in situ. The dialysis type micro-fluidic mixing device comprises a micro-fluidic mixing chip, a micro-fluidic dialysis chip, a sealing soft film, a dialysis membrane and a clamping and fixing assembly. The micro-fluidic mixing chip comprises a solution mixing inlet, a liposome solution outlet, a solution mixing unit and a liposome solution flow channel. The micro-fluidic dialysis chip comprises a dialysis liquid inlet, a dialysis liquid outlet and a dialysis liquid flow channel. The dialysis type micro-fluidic mixing device has an in-situ dialysis function, can realize the synthesis and purification treatment of liposomes in the same device, greatly shortens the process time and reduces the operation steps. In addition, the device has the advantages of being detachable, can be conveniently cleaned and dredged, has good reusability, and can replace the dialysis membrane with different molecular weight cut-off according to the use requirements, so as to meet the dialysis requirements of different drug-loaded liposomes.

Description

Technical Field

[0001] This invention belongs to the field of microfluidics and liposome preparation technology, and particularly relates to a dialysis-type microfluidic mixing device and a method for in-situ preparation and purification of liposomes using microfluidic mixing and microfluidic dialysis. Background Technology

[0002] Liposomes are closed vesicles composed of one or more phospholipid bilayers and have been widely used in fields such as anti-tumor drug delivery and gene therapy. By encapsulating drugs within liposomes, pharmacokinetic properties can be altered, drug circulation time prolonged, and toxic side effects reduced. Furthermore, by functionally modifying the surface of liposomes, targeted delivery can be achieved, precisely delivering drugs to specific tissues within the body.

[0003] Currently, common methods for preparing liposomes include thin-film hydration, reverse evaporation, and microfluidic methods. These methods all require subsequent purification of the prepared liposomes to remove unencapsulated drugs, ethanol, and other impurities. Prolonged purification processes (such as dialysis) can affect the particle size distribution of liposomes, causing leakage of the encapsulated drug. This not only reduces the production efficiency of liposomes but also limits their widespread application in the biomedical field.

[0004] Compared to traditional methods, microfluidic synthesis offers advantages such as simple operation, good batch-to-batch consistency, and the ability to control liposome particle size. However, most current microfluidic chips only function for liposome synthesis and cannot purify liposomes, significantly impacting the efficiency of microfluidic liposome synthesis. Therefore, developing a microfluidic mixing device capable of in-situ preparation and purification of liposomes is of great significance for promoting liposome production and its applications. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a dialysis-type microfluidic mixing device and a method for in-situ preparation and purification of liposomes. On one hand, this microfluidic mixing device enables the synthesis and dialysis of liposomes within the same chip, significantly shortening process time and reducing operational steps. On the other hand, the microfluidic mixing device of this invention has the advantage of being detachable, facilitating the cleaning and unblocking of microchannels and exhibiting good reusability. Furthermore, the device can be equipped with dialysis membranes of different molecular weight cutoffs to adapt to the dialysis requirements of different drug-loaded liposomes.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A dialysis-type microfluidic mixing device, characterized in that the device comprises a microfluidic mixing chip, a microfluidic dialysis chip, a sealing membrane, a dialysis membrane, and a clamping and fixing assembly; the microfluidic mixing chip includes a solution mixing inlet, a liposome solution outlet, a solution mixing unit, and a liposome solution flow channel; the solution mixing inlet includes an aqueous inlet and an ethanol inlet; the solution mixing inlet is connected to an external multi-channel microinjection pump device via a conduit; the liposome solution outlet delivers the product to a collection device via a conduit; the solution mixing unit includes a fluid focusing mixing unit and a spiral mixing unit; the liposome solution flow channel... The liposome solution channel is located on one side of the microfluidic mixing chip and is in close contact with the dialysis membrane. The liposome solution channel contains a herringbone mixing structure. The microfluidic dialysis chip includes a dialysate inlet, a dialysate outlet, and a dialysate channel. The dialysate inlet is connected to an external peristaltic pump device through a conduit. The dialysate outlet delivers the dialysate to a waste collection device through a conduit. The dialysate channel is located on one side of the microfluidic dialysis chip and is sealed with a sealing membrane. The liposome solution channel, dialysate channel, dialysis membrane, and sealing membrane together constitute a solution dialysis unit. The clamping and fixing assembly includes a perforated thin plate, a mating thin plate, bolts, and nuts.

[0008] Preferably, the microfluidic hybrid chip and the microfluidic dialysis chip are made of photocurable resin, polymethyl methacrylate (PMMA), or polydimethylsiloxane (PDMS).

[0009] Preferably, the inner diameter of the inlet and outlet ranges from 400 to 3000 μm, and the depth ranges from 0.5 to 5 mm.

[0010] Preferably, the microchannel width of the solution mixing unit is in the range of 50–1000 μm, and the depth is in the range of 50–1000 μm.

[0011] Preferably, the conduit connecting the inlet and outlet is made of polytetrafluoroethylene or silicone, with an inner diameter ranging from 200 to 2600 μm and an outer diameter ranging from 400 to 3000 μm.

[0012] Preferably, the dialysis membrane material is a cellulose dialysis membrane or a regenerated cellulose dialysis membrane.

[0013] Preferably, the sealing membrane material is PDMS, polyurethane (PU), or silicone, with a thickness ranging from 0.5 to 1.5 mm.

[0014] Preferably, the thickness of the perforated sheet and the mating sheet ranges from 3 to 8 mm, and the material is polymethyl methacrylate (PMMA) or polycarbonate (PC).

[0015] The present invention also provides a method for in-situ preparation and purification of liposomes using the above-mentioned dialysis-type microfluidic mixing device, which includes the following steps:

[0016] (1) Connect the aqueous inlet and ethanol inlet to the corresponding syringes through conduits, and discharge the liposome solution outlet to the collection device through a conduit; connect the dialysate inlet to the peristaltic pump, and discharge the dialysis waste liquid to the waste liquid collection device through a conduit.

[0017] (2) Prepare the corresponding solution by dissolving the liposome excipient in ethanol; depending on the solubility of the encapsulated drug, dissolve the water-soluble drug in the aqueous phase or the lipid-soluble drug in the lipid ethanol solution.

[0018] (3) According to a specific flow rate, use a multi-channel micro-injection pump to inject aqueous solution and lipid ethanol solution into the aqueous phase inlet and ethanol inlet respectively; use a peristaltic pump to inject ultrapure water or buffer solution into the dialysate inlet as dialysate.

[0019] (4) As the lipid ethanol solution and the aqueous solution are mixed in the fluid focusing mixing unit, the ethanol dissolves rapidly in the aqueous phase, resulting in a sharp decrease in the concentration of ethanol, which causes the lipid molecules to rapidly self-assemble into liposomes in the aqueous solution; then, they are further mixed in the spiral mixing unit, which makes the particle size more uniform; finally, the liposome solution flows through the solution dialysis unit, and the free drug and ethanol enter the dialysate through the dialysis membrane, thereby removing the free drug and ethanol in the liposome solution.

[0020] The beneficial effects of the dialysis-type microfluidic mixing device and the method for in-situ preparation and purification of liposomes provided by this invention are as follows:

[0021] (1) Compared with other microfluidic mixing chips used for liposome synthesis, the dialysis-type microfluidic mixing device of the present invention has the function of dialysis of liposomes, and can realize the synthesis and purification of liposomes in the same device, which greatly shortens the process time and reduces the number of operation steps.

[0022] (2) The microfluidic mixing device has the advantage of being detachable, which makes it easy to clean and unclog the dialysis unit and has good reusability; and it can replace the dialysis membrane with different molecular weight cutoff according to the needs of use to meet the dialysis requirements of different drug-loaded liposomes. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the dialysis-type microfluidic mixing device according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the microfluidic hybrid chip according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the structure of the microfluidic dialysis chip according to an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of the fluid focusing mixing unit according to an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the structure of the spiral mixing unit according to an embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of the herringbone hybrid structure according to an embodiment of the present invention;

[0029] Figure 7 This is a schematic diagram of the clamping and fixing assembly according to an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of a system for in-situ preparation and purification of liposomes using a dialysis-type microfluidic mixing device according to an embodiment of the present invention;

[0031] Figure 9 This is a comparison diagram of the particle size distribution of purified liposomes prepared using a dialysis-type microfluidic mixing device and a conventional dialysis method according to an embodiment of the present invention;

[0032] The components include: 1. Microfluidic mixing chip; 2. Dialysis membrane; 3. Sealing membrane; 4. Microfluidic dialysis chip; 5. Clamping and fixing assembly; 6. Multichannel microinjection pump; 7. Peristaltic pump; 8. Syringe; 9. Catheter; 101. Aqueous phase inlet; 102. Ethanol inlet; 103. Fluid focusing mixing unit; 104. Spiral mixing unit; 105. Liposome solution channel; 106. Liposome solution outlet; 401. Dialysis fluid inlet; 402. Dialysis fluid channel; 403. Dialysis fluid outlet; 501. Bolts and nuts; 502. Perforated thin plate; 503. Fitting thin plate; 10301. Lipid-ethanol solution channel; 10302. Aqueous solution channel; 10303. Fluid focusing area; 10304. Fluid mixing channel; 10401. Annular mixing structure; 10501. Herringbone mixing structure. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0034] This embodiment provides a dialysis-type microfluidic mixing device and a method for in-situ preparation and purification of liposomes.

[0035] A dialysis-type microfluidic mixing device, such as Figure 1 As shown, the microfluidic mixing device consists of a microfluidic mixing chip 1, a dialysis membrane 2, a sealing membrane 3, a microfluidic dialysis chip 4, and a clamping and fixing assembly 5. The microfluidic mixing chip 1 is provided with a solution mixing inlet, a liposome solution outlet, a solution mixing unit, and a liposome solution channel. The microfluidic dialysis chip 4 is provided with a dialysate inlet, a dialysate outlet, and a dialysate channel. The solution mixing unit is fabricated inside the microfluidic mixing chip 1. The liposome solution channel, the dialysate channel, the dialysis membrane 2, and the sealing membrane 3 together constitute the solution dialysis unit.

[0036] like Figure 2 As shown, the microfluidic mixing chip 1 is provided with an aqueous inlet 101, an ethanol inlet 102, a fluid focusing mixing unit 103, a spiral mixing unit 104, a liposome solution channel 105, and a liposome solution outlet 106. The aqueous inlet 101 is used to introduce an aqueous solution, and the ethanol inlet 102 is used to introduce a lipid-ethanol solution.

[0037] like Figure 3 As shown, the microfluidic dialysis chip 4 is provided with a dialysis fluid inlet 401, a dialysis fluid channel 402, and a dialysis fluid outlet 403, wherein the dialysis fluid inlet 401 is used to introduce dialysis fluid.

[0038] like Figure 2 and Figure 4 As shown, the fluid focusing and mixing unit 103 comprises a lipid ethanol solution channel 10301, an aqueous solution channel 10302, a fluid focusing region 10303, and a fluid mixing channel 10304. The two aqueous solution channels 10302 are annular in shape. The lipid ethanol solution channel 10301 and the aqueous solution channel 10302 converge in the fluid focusing region 10303 and further mix in the fluid mixing channel 10304.

[0039] like Figure 2 and Figure 5 As shown, the spiral mixing unit 104 is shaped as a spiral spatially distributed microchannel, and multiple arrayed annular mixing structures 10401 are provided on the microchannel. While increasing the liquid mixing time, the spiral mixing unit 104, with its distributed annular mixing structures 10401, can further improve the liquid mixing effect.

[0040] like Figure 2 and Figure 6 As shown, the liposome solution flow channel 105 is provided with multiple arrayed herringbone-shaped mixing structures 10501. The synthesized liposome solution exchanges substances with the dialysate through the dialysis membrane, and the herringbone-shaped mixing structures 10501 can further improve the efficiency of dialysis.

[0041] like Figure 1 and Figure 7 As shown, the clamping and fixing assembly 5 includes a perforated thin plate 502, a mating thin plate 503, and at least five sets of bolts and nuts 501. The perforated thin plate 502 has openings corresponding to the inlet and outlet. The bolts and nuts 501 are used to clamp the perforated thin plate 502 and the mating thin plate 503, so that the microfluidic hybrid chip 1, the microfluidic dialysis chip 4, and the dialysis membrane 2 and the sealing soft membrane 3 between them are tightly attached, achieving a sealing effect.

[0042] Preferably, the microfluidic hybrid chip 1 and the microfluidic dialysis chip 4 are made of photocurable resin, PMMA, or PDMS. The width of each channel on the microfluidic chip ranges from 50 to 1000 μm, the depth ranges from 50 to 1000 μm, the inner diameter of the inlet and outlet ranges from 400 to 3000 μm, and the depth ranges from 0.5 to 5 mm.

[0043] Preferably, the sealing membrane 3 is made of PDMS, PU, ​​or silicone, and has a thickness ranging from 0.5 to 1.5 mm.

[0044] Preferably, the perforated thin plate 502 and the mating thin plate 503 are made of PMMA or PC, with a thickness ranging from 3 to 8 mm.

[0045] This embodiment also provides a method for in-situ preparation and purification of liposomes.

[0046] like Figure 1 , Figure 2 and Figure 8 As shown, the method for in-situ preparation and purification of liposomes includes the following steps:

[0047] (1) Connect the aqueous inlet 101 and the ethanol inlet 102 to the corresponding syringes 8 through the conduit 9 respectively, and transport the product to the collection device through the conduit 9 through the liposome solution outlet 106; connect the dialysate inlet 401 to the peristaltic pump 7, and discharge the dialysis waste liquid to the waste liquid collection device through the conduit 9 through the dialysate outlet 403.

[0048] (2) Prepare the corresponding solution by dissolving the liposome excipient in ethanol; according to the solubility of the encapsulated drug, dissolve the water-soluble drug in an aqueous solution or the lipid-soluble drug in a lipid ethanol solution.

[0049] (3) According to a specific flow rate, a multi-channel micro-injection pump 6 is used to inject aqueous solution and lipid ethanol solution into aqueous phase inlet 101 and ethanol inlet 102 respectively; a peristaltic pump 7 is used to inject ultrapure water or dialysis buffer into dialysate inlet 401 as dialysate.

[0050] (4) As the lipid ethanol solution and the aqueous solution are mixed in the fluid focusing mixing unit 103, the ethanol dissolves rapidly in the aqueous phase, resulting in a sharp decrease in the concentration of ethanol, which causes the lipid molecules to rapidly self-assemble into liposomes in the aqueous solution; then, they are further mixed in the spiral mixing unit 104, which makes the particle size more uniform; finally, the liposome solution flows through the solution dialysis unit, and the free drug and ethanol enter the dialysate through the dialysis membrane, thereby removing the free drug and ethanol in the liposome solution.

[0051] Specifically, in step (3), the flow rate of different fluids in the microfluidic chip can be controlled by the multi-channel micro-injection pump 6.

[0052] Specifically, in step (4), the particle size distribution range of liposomes can be adjusted by changing the flow ratio of the aqueous phase to the lipid ethanol solution and the total flow rate. The dialysis efficiency can be adjusted by changing the flow ratio of the dialysate to the liposome solution and by replacing the dialysis membrane with a different molecular weight cutoff.

[0053] The specific operation process of this embodiment is as follows: using the microArch manufactured by Chongqing Mofang Precision Technology Co., Ltd. TM The S140 3D printer was used to fabricate the microfluidic mixing chip 1 and the microfluidic dialysis chip 4. The photocurable resin used in the printing was the GR model resin manufactured by Chongqing Mofang Precision Technology Co., Ltd. A schematic diagram of the assembled dialysis-type microfluidic mixing device is shown below. Figure 1 As shown, the dialysis membrane 2 and the sealing membrane 3 are clamped between the side of the microfluidic mixing chip 1 with the liposome solution channel 105 and the side of the microfluidic dialysis chip 4 with the dialysate channel 402, and then clamped together by the clamping and fixing assembly 5 to ensure that the liquid in the microchannel does not leak. Figure 2 As shown, the microfluidic mixing chip 1 has dimensions of 50 mm × 40 mm × 8 mm (length × width × height), and integrates an aqueous inlet 101, an ethanol inlet 102, a fluid focusing mixing unit 103, a spiral mixing unit 104, a liposome solution channel 105, and a liposome solution outlet 106. Figure 3 As shown, the microfluidic dialysis chip 4 has dimensions of 50 mm × 40 mm × 5 mm (length × width × height), and integrates a dialysate inlet 401, a dialysate channel 402, and a dialysate outlet 403. The inner diameter of the dialysate inlet 401 and the dialysate outlet 403 is 1.6 mm, and the depth is 2 mm. The width of the dialysate channel 402 is 1.5 mm, and the depth is 0.5 mm. A schematic diagram of the fluid focusing mixing unit 103 is shown below. Figure 4 As shown, it includes a lipid ethanol solution channel 10301, two aqueous solution channels 10302, a fluid focusing region 10303, and a fluid mixing channel 10304. A schematic diagram of the spiral mixing unit 104 is shown below. Figure 5As shown, the microchannels are spirally distributed, and multiple arrayed annular mixing structures 10401 are arranged within the microchannels. A schematic diagram of the liposome solution channel 105 is shown below. Figure 6 As shown, the flow channel is provided with multiple arrayed herringbone-shaped mixing structures 10501. The inner diameter of the aqueous inlet 101, ethanol inlet 102, and liposome solution outlet 106 is 1.6 mm, and the depth is 2 mm. The channel width of the focusing mixing unit 103 is 250 μm, and the depth is 250 μm. The diameter of the annular mixing structure 10401 in the spiral mixing unit 104 is 600 μm. The liposome solution flow channel 105 is 1.5 mm wide and 150 μm deep; the herringbone mixing structure 10501 is 300 μm wide and 700 μm deep. The dialysis membrane 2 is made of cellulose dialysis membrane with a molecular weight cutoff of 8000–14000 Da. The sealing membrane 3 is made of silicone rubber and has a length × width × height of 50 mm × 40 mm × 0.8 mm. The sealing membrane 3 contains a hollow structure with the same dimensions as the dialysate flow channel 402. A schematic diagram of the clamping and fixing assembly 5 is shown below. Figure 7 As shown, the perforated thin plate 502 and the mating thin plate 503 are made of PMMA, with dimensions of 70 mm × 60 mm × 8 mm (length × width × height). A schematic diagram of the system for in-situ preparation and purification of liposomes using a dialysis-type microfluidic mixing device is shown below. Figure 8 As shown, aqueous and lipid ethanol solutions are injected into their respective inlets at specific flow rates using a multi-channel microinjection pump 6. The aqueous inlet 101, ethanol inlet 102, and liposome solution outlet 106 are connected by AB glue and a conduit 9, which is a polytetrafluoroethylene capillary with an inner diameter of 1.2 mm and an outer diameter of 1.6 mm. The aqueous inlet is injected with a 50 μg / mL methylene blue solution; the ethanol inlet is injected with an anhydrous ethanol solution containing dipalmitoylphosphatidylcholine (DPPC), distearate phosphatidylethanolamine-polyethylene glycol 2000 (DSPE-PEG2000), and cholesterol in a molar ratio of 70:5:25. The concentration of DPPC in ethanol is 20 mmol / L, and the flow rate ratios of aqueous and ethanol are 4, 8, 12, 16, and 20, respectively, with a total flow rate of 1 mL / h. The dialysate is ultrapure water, injected into the dialysate inlet 401 via a peristaltic pump 7 at a flow rate of 900 mL / h. By adjusting the injection flow rate of methylene blue solution and lipid ethanol solution using a multi-channel microinjection pump, different flow rate ratios can be obtained, and liposomes with different particle size distributions can be further obtained, such as... Figure 9 As shown, purified liposomes prepared in situ using a dialysis-type microfluidic mixing device have a smaller particle size distribution compared to conventional dialysis methods.

[0054] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and all such modifications and improvements fall within the scope of protection of the present invention.

Claims

1. A dialysis-type microfluidic mixing device, characterized in that, The device includes a microfluidic mixing chip, a microfluidic dialysis chip, a sealing membrane, a dialysis membrane, and a clamping and fixing assembly. The microfluidic mixing chip includes a solution mixing inlet, a liposome solution outlet, a solution mixing unit, and a liposome solution channel. The solution mixing inlet includes an aqueous inlet and an ethanol inlet. The solution mixing inlet is connected to an external multi-channel microinjection pump via a conduit. The liposome solution outlet delivers the product to a collection device via a conduit. The solution mixing unit includes a fluid focusing mixing unit and a spiral mixing unit. The liposome solution channel is located on one side of the microfluidic mixing chip and is in close contact with the dialysis membrane; the liposome solution channel contains a herringbone mixing structure. The microfluidic dialysis chip includes a dialysate inlet, a dialysate outlet, and a dialysate channel. The dialysate inlet is connected to an external peristaltic pump via a conduit. The dialysate outlet delivers the dialysate to a waste collection device via a conduit. The dialysate channel is located on one side of the microfluidic dialysis chip and is sealed by a sealing membrane. The liposome solution channel, dialysate channel, dialysis membrane, and sealing membrane together constitute a solution dialysis unit. The clamping and fixing assembly includes a perforated thin plate, a mating thin plate, bolts, and nuts. The perforated thin plate, microfluidic mixing chip, dialysis membrane, sealing membrane, microfluidic dialysis chip, and mating thin plate are arranged sequentially from top to bottom and secured with bolts and nuts.

2. The dialysis-type microfluidic mixing device as described in claim 1, characterized in that, The materials used to fabricate the microfluidic mixing chip and the microfluidic dialysis chip are independently selected from photocurable resin, polymethyl methacrylate, or polydimethylsiloxane; the inner diameter of the aqueous inlet, ethanol inlet, liposome solution outlet, dialysate inlet, and dialysate outlet ranges from 400 μm to 3000 μm, and the depth ranges from 0.5 mm to 5 mm; the microchannel width of the solution mixing unit ranges from 50 μm to 1000 μm, and the microchannel depth ranges from 50 μm to 1000 μm.

3. The dialysis-type microfluidic mixing device as described in claim 1, characterized in that, The sealing membrane is a transparent polymer membrane made of polydimethylsiloxane, polyurethane, or silicone, with a thickness ranging from 0.5 mm to 1.5 mm.

4. The dialysis-type microfluidic mixing device as described in claim 1, characterized in that, The dialysis membrane material is a cellulose dialysis membrane or a regenerated cellulose dialysis membrane.

5. The dialysis-type microfluidic mixing device as described in claim 1, characterized in that, The materials of the perforated thin plate and the mating thin plate are polymethyl methacrylate or polycarbonate, with a thickness ranging from 3 mm to 8 mm.

6. The dialysis-type microfluidic mixing device as described in claim 1, characterized in that, The fluid focusing and mixing unit consists of a lipid ethanol solution channel, an aqueous solution channel, a fluid focusing region, and a fluid mixing channel. There are two aqueous solution channels, which are annular in shape. The lipid ethanol solution channel and the aqueous solution channel converge in the fluid focusing region and are further mixed in the fluid mixing channel. The spiral mixing unit is a spirally distributed microchannel with multiple arrayed annular mixing structures on it.

7. The dialysis-type microfluidic mixing device as described in claim 1, characterized in that, The liposome solution channel is provided with multiple arrayed herringbone-shaped mixing structures; the synthesized liposome solution exchanges substances with the dialysate through a dialysis membrane; the width of the liposome solution channel ranges from 50 μm to 1000 μm, and the depth ranges from 50 μm to 1000 μm.

8. A method for preparing purified liposomes using the dialysis-type microfluidic mixing device as described in any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Piping connection: Connect the aqueous phase inlet and the ethanol inlet to the corresponding syringes through the tubing respectively. Discharge the liposome solution outlet to the collection device through the tubing. Connect the dialysate inlet to the peristaltic pump. Discharge the dialysis waste liquid to the waste liquid collection device through the tubing. (2) Solution preparation: Dissolve the liposome excipients in ethanol; depending on the solubility of the encapsulated drug, dissolve the water-soluble drug in the aqueous phase, or dissolve the lipid-soluble drug in the lipid ethanol solution; (3) Fluid injection: At a certain flow rate, a multi-channel micro-injection pump is used to inject aqueous solution and lipid ethanol solution into the aqueous phase inlet and the ethanol inlet respectively; Use a peristaltic pump to inject ultrapure water or buffer solution into the dialysate inlet; (4) Mixing and dialysis: As the lipid ethanol solution and the aqueous solution are mixed in the fluid focusing mixing unit, the ethanol dissolves rapidly in the aqueous phase, resulting in a sharp decrease in the concentration of ethanol, which causes the lipid molecules to rapidly self-assemble into liposomes in the aqueous solution; then, further mixing is carried out in the spiral mixing unit to make the particle size more uniform; finally, the liposome solution flows through the solution dialysis unit, and the free drug and ethanol enter the dialysate through the dialysis membrane, thereby removing impurities in the liposome solution.

9. The method for preparing purified liposomes as described in claim 8, characterized in that, The flow rates of the aqueous and lipid ethanol solutions were controlled using a multichannel microinjection pump.

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