Flow channel structure for removing foreign matter, method for removing foreign matter, and method for manufacturing lipid particles

Abstract

According to one embodiment, a flow channel structure for removing foreign matter includes a first flow channel. The first flow channel has a first region having a depth shallower than a depth of another region.

Description

[0001] Cross-references to related applications

[0002] This application is based on and claims priority to Japanese Patent Application No. 2021-091332, filed on May 31, 2021, the entire contents of which are incorporated herein by reference.

[0003] field

[0004] The implementation schemes described herein typically involve flow channel structures for removing foreign matter, methods for removing foreign matter, and methods for manufacturing lipid particles. Background Technology

[0005] In microchannel fluid handling techniques, various channel shapes are designed for purposes such as fluid mixing and the addition or removal of substances. In such channels, it is important that the shape exhibits the desired effect as designed. One factor that inhibits this is the mixing of foreign matter. Methods exist to remove foreign matter by pre-filtering the fluid with a filter, but concerns arise regarding contamination and complex structures resulting from filter installation. For example, when the frequency of foreign matter generation is low, it may be more effective not to use a filter, considering the effects of using a filter as described above. However, even small amounts of foreign matter often affect the effectiveness of the channel structure. Therefore, there is a need to develop channel structures that reduce the impact of foreign matter without using filters.

[0006] Furthermore, microfluidic channels are preferably disposable products when contamination is desired, such as in medical applications. However, complex structures are required to perform various operations within microfluidic channels, and cost reduction is difficult due to the precision required in manufacturing microfluidic chips. Therefore, low-cost microfluidic chips are needed.

[0007] Brief description of the attached diagram

[0008] [ Figure 1 ] Figure 1 These are plan and cross-sectional views illustrating an example of the flow channel structure in the first implementation scheme.

[0009] [ Figure 2 ] Figure 2 This is a perspective view illustrating an example of the flow channel structure in the first implementation scheme.

[0010] [ Figure 3 ] Figure 3 This is a plan view illustrating an example of a flow channel structure in a first embodiment connected to the upstream of the mixing flow channel.

[0011] [ Figure 4 ] Figure 4 This is a plan view illustrating an example of the flow channel structure in the second implementation scheme.

[0012] [ Figure 5 ] Figure 5 This is a plan view illustrating an example of the flow channel structure in the third implementation scheme.

[0013] [ Figure 6 ] Figure 6 This is a plan view illustrating an example of the flow channel structure in the fourth implementation scheme.

[0014] [ Figure 7 ] Figure 7 This is a perspective view illustrating an example of the flow channel structure in the fourth implementation scheme.

[0015] [ Figure 8 ] Figure 8 This is a plan view illustrating an example of the flow channel structure in the fourth implementation scheme.

[0016] [ Figure 9 ] Figure 9 This is a perspective view illustrating an example of the flow channel structure in the fourth implementation scheme.

[0017] [ Figure 10 ] Figure 10 This is a plan view illustrating an example of the flow channel structure in the fifth implementation scheme.

[0018] [ Figure 11 ] Figure 11 This is a cross-sectional view illustrating an example of a flow channel structure in the implementation scheme.

[0019] [ Figure 12 ] Figure 12 This is a cross-sectional view illustrating an example of lipid particles in the implementation scheme.

[0020] [ Figure 13 ] Figure 13 This is a flowchart illustrating an example of a method for manufacturing lipid particles according to an implementation plan.

[0021] [ Figure 14 ] Figure 14 This is a plan view illustrating an example of the flow channel structure of lipid particles in a manufacturing implementation scheme.

[0022] [ Figure 15 ] Figure 15 This is a block diagram illustrating the flow channel structure used in the experiment of the embodiment.

[0023] [ Figure 16 ] Figure 16 These are photomicrographs showing the experimental results of the examples.

[0024] Implementation Plan Description

[0025] Typically, according to one embodiment, the flow channel structure for removing foreign objects includes a first flow channel, and the first flow channel has a first region having a depth that is shallower than that of another region.

[0026] In the following description, embodiments will be illustrated with reference to the accompanying drawings. Note that in each embodiment, substantially the same components are indicated by the same reference numerals, and their description may be partially omitted. The drawings are schematic, and the relationships between the thickness and planar dimensions of each part, the thickness ratios of each part, etc., may differ from the actual figures.

[0027] - Flow channel structure for removing foreign objects

[0028] The flow channel structure for removing foreign matter according to the embodiment has a configuration for capturing foreign matter in the flow channel. Therefore, foreign matter is removed from the fluid, and its downstream flow can be inhibited. Note that in this specification, "capture" does not necessarily mean capturing all foreign matter contained in the fluid, and includes capturing some foreign matter. Therefore, the flow channel structure for removing foreign matter according to the embodiment does not necessarily remove all foreign matter, but can remove at least some. Hereinafter, the flow channel structure for removing foreign matter is also simply referred to as the "flow channel structure of the embodiment" or "flow channel structure".

[0029] The following sections will describe some implementation schemes for the flow channel structure used to remove foreign objects.

[0030] (First Implementation Plan)

[0031] As in Figure 1 As illustrated in the plan view of part (a), the flow channel structure 1 of the first embodiment includes a first flow channel 2. Here, the first flow channel 2 is a cavity formed inside the flow channel structure 1, i.e., its top surface has a cap and is constructed in a liquid-sealed manner. For example, the first flow channel 2 is a microchannel. Note that in this figure, the direction of fluid movement is indicated by arrows.

[0032] The first flow channel 2 has a first region, which has a shallower depth than the other region. The first region is also referred to below as the shallow portion 3. Figure 1 Part (b) explains along Figure 1 A cross-sectional view obtained from the midline B-B' in part (a). In shallow part 3, for example, the bottom surface bulges towards the top surface. Therefore, the depth d1 of shallow part 3 is shallower than the depth d2 of the region upstream of shallow part 3 (hereinafter also referred to as "upstream deep part 4"). The depth d2 of upstream deep part 4 and the depth d3 of the region downstream of shallow part 3 (hereinafter also referred to as "downstream deep part 5") can be approximately the same.

[0033] Figure 2 This describes the state of the fluid as it flows through flow channel structure 1. The arrows indicate the direction of fluid movement. When the fluid passes through shallow section 3, foreign objects 6 larger than the depth d1 of shallow section 3 cannot enter shallow section 3 and are immediately captured in front of shallow section 3. Therefore, it can prevent foreign objects 6 from flowing downstream.

[0034] There is no limit to the depth d1 of the shallow portion 3. For example, if a foreign object 6 of a certain size or shape adversely affects the effect of a flow channel structure separately provided downstream of the flow channel structure 1, the depth d1 is set to a depth that can capture the foreign object 6 of a certain size or shape.

[0035] An example of a method for setting the depth d1 of the shallow section 3 will be described using an example of a flow channel structure 1 configured upstream of a two-liquid mixing flow channel structure for mixing two liquids. For example, in Figure 3 The flow channel structure 10 illustrated in the plan view includes two flow channel structures 1a and 1b for removing foreign matter, and a Y-shaped two-liquid mixing flow channel structure 11, wherein a second flow channel 12 connected downstream of one flow channel structure 1a and a third flow channel 13 connected downstream of the other flow channel structure 1b merge to form a fourth flow channel 14. Note that the diagonal lines in the figure indicate the shallow portion (the same applies to the figure below).

[0036] The second flow channel 12 has a second region that has a shallower depth than the fourth flow channel 14 at its end near the fourth flow channel 14 (hereinafter referred to as "shallow section 3c"). The shallow section 3c has the function of generating eddies in the fluid when the two liquids converge in the fourth flow channel 14. The eddies promote mixing and regulate the two fluids.

[0037] The fluid that removes foreign matter 6 through flow channel structure 1a is supplied to the second flow channel 12, and the fluid that removes foreign matter 6 through flow channel structure 1b is supplied to the third flow channel 13. In the case where foreign matter 6 enters the second flow channel 12 and is trapped in the shallow portion 3c without the flow channel structure 1a provided, the foreign matter 6 is blocked in the shallow portion 3c of the second flow channel 12, thus blocking the flow channel. Furthermore, even when the flow channel is not completely blocked by foreign matter 6, the foreign matter 6 suppresses the generation of eddies and may worsen the mixing function.

[0038] When the purpose is to prevent the inflow of foreign matter 6 of a size that is blocked at the shallow portion 3c, the depth d1 of the shallow portion 3a of the flow channel structure 1a is preferably equal to or less than the depth of the shallow portion 3c. Here, "equal to" includes the case where the difference in operational accuracy is ±0.01 mm. For example, when the depth of the fourth flow channel 14 is 0.3 mm and the depth of the shallow portion 3c is 0.1 mm (which is 1 / 3 of the depth of the fourth flow channel 14), the depth d1 of the shallow portion 3a is preferably 0.1 mm or less. As described above, by installing a flow channel structure 1a that includes a shallow portion 3a having a depth equal to or less than the depth of the shallow portion 3c of the two-liquid mixing flow channel structure 11, it is easy to prevent foreign matter 6 from entering and for the fluid that has removed foreign matter 6 to flow into the two-liquid mixing flow channel structure 11.

[0039] On the other hand, if a small foreign object 6 is present that passes through the shallow portion 3a, the foreign object 6 is unlikely to block the shallow portion 3c and can therefore be excluded from consideration. In this case, the depth of the shallow portion 3a can be similar to the depth of the shallow portion 3c. However, if it is preferable to remove the small foreign object 6 that is less likely to cause blockage in the shallow portion 3c, the depth of the shallow portion 3a can be shallower than the depth of the shallow portion 3c.

[0040] The two-liquid mixing flow channel structure 11 is not limited to this shape and may have, for example, a T-shape, in which the fourth flow channel 14 is simply connected in series downstream of the second flow channel 12 to form an integrated linear flow channel, and the third flow channel 13 is connected at a right angle to the upstream end of the fourth flow channel 14. Additionally, as described below... Figure 14 The description states that the two-liquid mixing channel structure 11 may also include a channel that is connected downstream of the fourth channel 14 and further mixes and agitates the fluid.

[0041] As described in the examples above, the flow channel structure 1 of the embodiment can be installed upstream of a flow channel structure with a certain function and can be used to prevent foreign matter 6 from entering the flow channel structure. The flow channel structure on which the flow channel structure 1 is installed is not limited to the two-liquid mixing flow channel structure 11, and can be installed in any flow channel structure where the entry of foreign matter 6 may have an adverse effect. In addition, the flow channel structure 1 can be set in the flow channel through which the fluid in which foreign matter 6 is expected to be present at that time flows, but it is also preferred to set the flow channel structure 1 in all flow channels for preventing the generation and entry of unforeseen foreign matter 6.

[0042] Although the third flow channel 13 does not have a shallow section, it is preferable to provide a flow channel structure 1b to prevent foreign matter 6 from entering. For example, Figure 3 The shallow portion, for example, shallow portion 3c, which is directly connected downstream of shallow portion 3b, is not specified, but this is considered in the following description. Figure 14 In the case where a shallow section is further arranged downstream of the fourth flow channel 14 as described above, it is preferable to provide a shallow section in both flow channel structures 1a and 1b.

[0043] Generally, since the depth d1 of the shallow part 3 is set according to the purpose described above, the depth d1 is not limited, but it can be shallower than the depth d2 of the upstream deep part 4, and preferably less than 1 / 2 of the depth d2, and can be 1 / 3, 1 / 4, 1 / 5 of the depth d2, etc.

[0044] In addition, since the mold forming or cutting accuracy of the preferred method for manufacturing this flow channel structure 1 is usually 5 μm, it is desirable that the depth d1 of the shallow part 3 be at least 10 μm or greater in order to avoid flow channel blockage due to errors.

[0045] The length of the shallow portion 3 in the direction of fluid flow is preferably the same as the width of the first flow channel 2. Alternatively, the length may be shorter, as long as it can be manufactured.

[0046] The width and depth of the upstream depth 4 and the downstream depth 5, and the volume of fluid supplied, are not limited and are determined according to the type of fluid. When a foreign object 6 has a thickness (0.1 mm to 0.2 mm) equal to or less than the thickness of a human hair (which is often referred to as the limit of visual perception), it is difficult for the user of the flow channel to notice the foreign object 6 immediately. Therefore, this structure is particularly desirable in normal microchannels (e.g., with a width and depth of approximately 3 mm or less) where the mixing of foreign objects of 0.2 mm or less could cause significant problems.

[0047] On the other hand, when using a pump in this flow channel structure, a pump that does not cause pulsation is preferred. Such a pump can be readily obtained with a liquid supply rate of approximately 1 ml / s. Taking this into consideration, a suitable upper limit for the width and depth of each of the cross-sections of the upstream depth 4 and the downstream depth 5 can be approximately 3 mm.

[0048] For example, the width and depth of each cross section in the upstream deep section 4 and the downstream deep section 5 are preferably 0.1 mm to 3 mm.

[0049] The flow velocity of the fluid flowing through the flow channel structure 1 is preferably relatively slow. Therefore, the possibility of foreign matter 6 trapped in the shallow section 3 being discharged and flowing downstream due to increased pressure can be reduced. Additionally, it can prevent an increase in pressure resistance when a large number of foreign matter 6 is trapped.

[0050] The flow channel structure 1 has a simple shape in which a shallow portion 3 is provided, and can remove foreign matter 6 without using complex structures such as filters. Although the flow channel structure 1 will be described in detail below, the flow channel structure 1 is easy to manufacture and can reduce costs.

[0051] (Second Implementation Plan)

[0052] The flow channel structure of the second embodiment includes a shallow portion 3 with a wide width. Here, the width refers to the length of the first flow channel 2 in a direction orthogonal to the flow direction of the fluid.

[0053] For example, in Figure 4 The flow channel structure 20 illustrated in the plan view of part (a) has a configuration in which a wide flow channel width is maintained from slightly upstream of the shallow portion 3 of the first flow channel 2 to slightly downstream of the shallow portion 3. In other words, the flow channel structure 20 has a rectangular wide portion 22 including the shallow portion 3.

[0054] Additionally, for example in Figure 4 In the flow channel structure 21 of part (b), the flow channel width gradually increases from slightly upstream of the first flow channel 2 to the shallow part 3, becoming the widest at the shallow part 3, and gradually returning to its original width towards slightly downstream of the shallow part 3. In other words, the flow channel structure 21 has a diamond-shaped wide portion 23, which has the widest width at the shallow part 3.

[0055] When the length l1 of the fluid in the flow direction from the upstream end of the wide portion 22 or 23 to the shallow portion 3 and the length l2 of the fluid in the flow direction from the shallow portion 3 to the downstream end of the wide portion 22 or 23 are too long, the dead volume in the entire microchannel increases, and when the length is too short, the resistance due to trapped foreign matter 6 can increase significantly. Therefore, in order to easily, substantially, and uniformly diffuse the foreign matter 6, it is desirable that the width of the foreign matter 6 is the same as the width of the wide portion 22. The lengths l1 and l2 may be the same or different from each other.

[0056] By setting the width of the shallow portion 3 to be wide in this way, the increase in pressure resistance in the shallow portion 3 can be suppressed, and the average flow velocity in the shallow portion 3 can be set to be equal to or less than the flow velocity when fluid is supplied to the first flow channel 2. For example, to obtain such a flow velocity, it is preferable that the cross-sectional area of ​​the flow channel of the shallow portion 3 is the same as or larger than that of the upstream deep portion 4. Therefore, when the depth d1 of the shallow portion 3 is 1 / n of the depth d2 of the upstream deep portion 4, the increase in pressure resistance can be eliminated when the width of the shallow portion 3 is set to n times the width of the flow channel of the upstream deep portion 4 (i.e., the relationship is w2 = w1 × n, where the width of the flow channel upstream of the wide portion 22 or 23 is w1 and the width of the flow channel including the shallow portion 3, 22 or 23, is w2). The average flow velocity at the shallow portion 3 can be set to the same level.

[0057] In addition, according to the implementation plan, foreign objects 6 are dispersed and captured in the width direction, and the possibility of foreign objects 6 blocking the flow channel can also be reduced.

[0058] (Third Implementation Plan)

[0059] The flow channel structure of the third embodiment has a configuration for collecting and capturing foreign matter 6 at one location. For example, in Figure 5 The flow channel structure 30 described in part (a) has a crank-like shape in which the first flow channel 2 is bent at right angles immediately in front of and immediately behind the shallow portion 3. That is, the flow channel structure 30 includes a front portion 2a of the first flow channel 2, a shallow portion 3 connected at a right angle to a flow channel wall at the downstream end of the front portion 2a in the flow direction, and a rear portion 2b of the first flow channel connected at a right angle to the downstream end of the shallow portion 3 in the flow direction. The flow direction in the rear portion 2b is parallel to and in the same direction as the flow direction in the front portion 2a.

[0060] The rear portion 2b need not be connected at a right angle in the flow direction of the shallow portion 3, and the first flow channel 2 can be bent at a right angle at least immediately in front of the shallow portion 3. For example, the rear portion 2b can be connected in series to an extension of the shallow portion 3.

[0061] According to this configuration, when the fluid flowing upstream of the front part 2a contacts the end of the front part 2a and bends at a right angle, the foreign object 6 moves along the extension of the flow immediately in front of it due to its inertia, and is thus collected and captured at the downstream end of the front part 2a. In addition, by arranging the foreign object 6 at the end, the flow bends in front of the end, preventing the captured foreign object 6 from being discharged into the shallow part 3.

[0062] Additionally, for example, as in Figure 5 In the flow channel structure 31 described in part (b), the first flow channel 2 is bent into an arc shape, and one flow channel wall 2c is depicted as an arc with a greater curvature than the other flow channel wall 2d facing the flow channel wall 2c. Therefore, foreign matter 6 is collected at one end of the flow channel wall 2c with greater curvature.

[0063] Using the above structure, foreign matter 6 is collected at one location, and fluid flows smoothly in another area, thereby mitigating the increase in pressure resistance caused by foreign matter 6.

[0064] (Fourth Implementation Plan)

[0065] The flow channel structure of the fourth embodiment also includes a structure for filtering foreign matter 6 (hereinafter referred to as the "filter structure"), which is disposed on the shallow portion 3. For example, see reference to Figures 6 to 9 An example of a flow channel structure comprising multiple protrusions is described as a filter structure.

[0066] exist Figure 6 floor plan and Figure 7 The flow channel structure 40 illustrated in the perspective view includes a plurality of elongated protrusions 7 on the shallow portion 3. For example, a plurality of protrusions 7 are arranged at parallel intervals in the flow direction in the first flow channel 2. The intervals are, for example, equal intervals. Fluid can pass through the gaps between the protrusions 7. Using this configuration, foreign objects 6 of a size or shape that cannot enter the gaps between the protrusions 7 can be further captured. The interval between the protrusions 7 is determined according to the size or shape of the foreign object 6 to be removed and is not limited, but from the point of view of mass production efficiency, for example, the width of one of the shallow portions 3 between adjacent protrusions is preferably approximately equal to or greater than the depth d1 of the shallow portion 3. The length of the protrusions 7 in the depth direction is not limited, but from the point of view of mass production efficiency, it is preferably approximately the same as the width of one of the protrusions 7 and does not need to contact the top surface of the first flow channel 2. In addition, the protrusions 7 do not have to be elongated cuboids and can have zigzag shapes, curved shapes, curved surfaces, etc. In addition, the length of the protrusions 7 in the flow direction can be the same as the length of the shallow portion 3 and can be shorter than the length of the shallow portion 3.

[0067] Additionally, for example in Figure 8 floor plan and Figure 9The flow channel structure 41 illustrated in the perspective view includes a plurality of cylindrical protrusions 8 extending in the depth direction of the first flow channel 2. For example, in a plan view, the plurality of protrusions 8 are arranged in an alternating manner. Fluid can pass through the shallow portion 3 and thus through the gaps between the protrusions 8. Using this configuration, foreign objects 6 of a size or shape that cannot enter the gaps between the protrusions 8 can be further captured. The spacing or arrangement of the protrusions 8 is determined according to the size or shape of the foreign object 6 to be removed and is not limited, and can be irregular shapes, etc., rather than alternating shapes. The length of the protrusions 8 in the depth direction is not limited, but from the point of view of mass production rate, it is preferable to be approximately the same as the diameter of one of the protrusions 8, and it does not need to contact the top surface of the first flow channel 2. In addition, the protrusions 8 do not have to be cylindrical, and can be polygonal pillars, plate shapes, etc.

[0068] The filter structure can also capture foreign objects 6. In particular, it can effectively capture slender foreign objects 6 such as fibers. In addition, with the filter structure, the flow rate can be set faster than in a flow channel structure without a filter structure because the captured foreign objects 6 are prevented from being discharged onto the shallow part 3.

[0069] (Fifth Implementation Plan)

[0070] The flow channel structure of the fifth embodiment includes multiple shallow sections 3. For example, Figure 10 The flow channel structure 50 described herein includes three shallow sections: a first shallow section 53a, a second shallow section 53b disposed downstream of the first shallow section 53a, and a third shallow section 53c disposed downstream of the second shallow section 53b. The first shallow section 53a, the second shallow section 53b, and the second shallow section 53c may have interconnected depths or different depths. By providing multiple shallow sections 3, foreign matter 6 can be captured, and a larger quantity of foreign matter 6 can be captured. For example, foreign matter 6 can be captured more effectively compared to the case of providing a single long shallow section 3. Furthermore, according to this structure, the depth of the flow channel is varied in each shallow section; therefore, the flow is guided to the bottom immediately downstream of each shallow section, where longitudinal vortices can be generated. Thus, the effect of smaller foreign matter 6 being gradually captured and removed by the longitudinal vortices can be anticipated.

[0071] - Methods for manufacturing flow channel structures

[0072] The following will be referenced Figure 11 The method described above for manufacturing the flow channel structure (hereinafter collectively referred to as "flow channel structure 100") for each embodiment is described above. For example, in Figure 11 As described in part (a), the flow channel structure 100 includes, for example, a substrate 102 in which a groove 101 is formed to serve as a flow channel, and a plate-shaped cover 103 coupled to the substrate 102 such that the top surface of the groove 101 is closed.

[0073] Depending on the application, the material of the substrate 102 may be suitably selected from resins such as acrylic resins, polyethylene resins and polypropylene resins, glass, ceramics, and metals. For example, when the flow channel structure 100 is used for medical purposes, cyclic olefin polymers are also preferred examples. For stability when the flow channel structure is reused several times, ceramics such as quartz are preferred, and metals with surfaces treated for corrosion resistance can be used when adjusting temperatures, etc. The groove 101 can be formed by pressure processing or cutting using, for example, a mold. At the location corresponding to the shallow portion 3, the groove 101 may be formed or cut shallower than other portions.

[0074] The material for the cover 103 can be, for example, the same material described for the base material 102. The cover 103 may have, for example, a plate shape. Alternatively, as... Figure 11 As described in part (b), a film-shaped cover 104 may be used.

[0075] A sensor terminal 105 for monitoring fluid states can be connected to a membrane cover 104. Alternatively, various functions or characteristics, such as high thermal conductivity and the ability to perform specific treatments on specific substances, can be assigned to the cover 104 (not shown).

[0076] When there are concerns that the cover 104 may expand due to internal pressure, such as Figure 11 As described in part (c), expansion can be suppressed by pressing down the pressure plate 106 from above the cover 104. The pressure plate 106 may include a heat medium flow channel 107 for heat exchange arranged therein, an electrical connector (not shown) with sensor function, etc.

[0077] Therefore, the flow channel structure 100 can be manufactured by a simple process of forming a groove 101 with a shallow portion 3 at the bottom height in the substrate 102 and attaching the cover portion 103 or 104 to the substrate 102. Thus, for example, it is not necessary to form irregularities in the substrate 102 and the cover portion 103 and to precisely align the substrate 102 and the cover portion 103, resulting in a very high mass production rate and the ability to manufacture the flow channel structure at low cost.

[0078] -Methods for removing foreign objects

[0079] According to the embodiments, a method for removing foreign matter using the flow channel structure of the embodiments is provided. The method for removing foreign matter includes flowing fluid into a first flow channel 2 of the flow channel structure of any of the embodiments described above. As a result, foreign matter 6 can be captured in the shallow section 3, and fluid with foreign matter 6 removed can be supplied downstream.

[0080] - Methods for manufacturing lipid particles that encapsulate drugs

[0081] The following describes a method for using the flow channel structure of the embodiment to manufacture lipid particles that encapsulate drugs.

[0082] First, the lipid particles manufactured by this method will be described. For example... Figure 12 As described, each lipid particle 200 includes a lipid membrane formed by arranging lipid molecules and has a substantially hollow spherical shape. Drug 202 is encapsulated within the lumen 201 of the lipid particle 200. The lipid particle 200 can be used, for example, to deliver drug 202 into cells.

[0083] like Figure 13 The manufacturing method described herein includes, for example, the following steps: flowing a first solution containing lipids as lipid particles in an organic solvent and a second solution containing a drug in an aqueous solvent into a first flow channel 2 of the flow channel structure of the embodiment and removing foreign matter from the fluid (foreign matter removal step S1); mixing the first solution and the second solution after removing foreign matter to obtain a mixed solution (mixing step S2); granulating the lipids to form lipid particles encapsulating the drug by reducing the concentration of the organic solvent in the mixed solution (granulation step S3); and concentrating the lipid particle solution (concentration step S4).

[0084] The following will describe process examples of this manufacturing method, and firstly, the first solution and the second solution will be described.

[0085] The first solution contains lipids in an organic solvent. The lipids are lipids that constitute the material of lipid particles 200. The first solution can be prepared by mixing lipids and an organic solvent. The lipids can be, for example, lipids that are major components of biological membranes. Furthermore, the lipids can be artificially synthesized. The lipids can include, for example, basic lipids such as phospholipids or sphingolipids, such as diacylphosphatidylcholine, diacylphosphatidylethanolamine, ceramides, sphingomyelin, dihydrosphingomyelin, cephalin, or cerebrosides, or combinations thereof.

[0086] For example, 1,2-dioleoyl-sn-glycerol-3-phosphate ethanolamine (DOPE), 1,2-distearate-sn-glycerol-3-phosphate ethanolamine (DSPE), 1,2-dipalmitoyl-sn-glycerol-3-phosphatidylcholine (DPPC), 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatidylcholine (POPC), 1,2-di-O-octadecyl-3-trimethylammonium-propane (DOTMA), 1,2-dioleoyl-3-dimethylammonium-propane (DODAP), and 1,2-dimyristoyl-3-dimethylammonium-propane (14:0DAP) are preferably used as the base lipids. 1,2-Dipalmitoyl-3-dimethylammonium-propane (16:0DAP), 1,2-distearate-3-dimethylammonium-propane (18:0DAP), N-(4-carboxybenzyl)-N,N-dimethyl-2,3-bis(oleoyloxy)propane (DOBAQ), 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), 1,2-dioleoyl-sn-glycerol-3-phosphocholine (DOPC), 1,2-dilauroyl-sn-glycerol-3-phosphocholine (DLPC), 1,2-dioleoyl-sn-glycerol-3-phospho-L-serine (DOPS), or cholesterol, or combinations thereof. In particular, DOTAP and / or DOPE are preferred.

[0087] Preferably, the lipid further comprises a first lipid compound and / or a second lipid compound as a biodegradable lipid. The first lipid compound may be represented by the formula Q-CHR2. (In this formula, Q is a nitrogen-containing aliphatic group containing two or more tertiary nitrogen atoms and free of oxygen, and R is independently C.) 12 To C 24 An aliphatic group, and at least one R contains a linking group LR in its main chain or side chain, the linking group LR being selected from -C(=O)-O-, -OC(=O)-, -OC(=O)-O-, -SC(=O)-, -C(=O)-S-, -C(=O)-NH-, and -NHC(=O)-.

[0088] The first lipid compound is, for example, a lipid having a structure represented by the following formula.

[0089] [Chemical Formula 1-1]

[0090]

[0091]

[0092] [Chemical Formula 1-2]

[0093]

[0094]

[0095] [Chemical Formulas 1-3]

[0096]

[0097]

[0098] Lipid compounds of formula (1-01) and / or lipid compounds of formula (1-02) are particularly preferred.

[0099] The second lipid compound can be represented by the formula P-[XWY-W'-Z]2. (In this formula, P is an alkylene group having one or more ether bonds in its main chain, X is a divalent linking group including a tertiary amine structure, W is a C1 to C6 alkylene group, Y is a divalent linking group selected from single bonds, ether bonds, carboxylic acid ester bonds, thiocarboxylic acid ester bonds, thioester bonds, amide bonds, carbamate bonds, and urea bonds, W' is a single bond or a C1 to C6 alkylene group, and Z is a fat-soluble vitamin residue, sterol residue, or C1 to C6 alkylene group.) 12 To C 22 Aliphatic hydrocarbon groups.

[0100] The second lipid compound is, for example, a lipid having a structure represented by the following formula.

[0101] [Chemical Formula 2-1]

[0102]

[0103]

[0104] [Chemical Formula 2-2]

[0105]

[0106]

[0107] Compounds of formula (2-01) are particularly preferred.

[0108] In the presence of both the first and second lipid compounds, the amount of drug 202 encapsulated in the lipid particles 200 can be increased, as can the efficiency of drug 202 entry into cells. Additionally, cell death in cells in which drug 202 has been introduced can be reduced. The content of the base lipid is preferably about 30% to about 80% (molar ratio) relative to the total lipid material. Alternatively, the base lipid may constitute approximately 100% of the lipid material. The content of the first and second lipid compounds is preferably about 20% to about 70% (molar ratio) relative to the total lipid material.

[0109] It is also preferred that the lipids include lipids that prevent flocculation of the lipid particles 200. For example, it is preferred that the lipids preventing flocculation also contain PEG-modified lipids, such as polyethylene glycol (PEG) dimyristoglycerol (DMG-PEG), polyamide oligomers derived from ω-amino(oligoethylene glycol) alkyl acid monomers (US 6,320,017B), or monosialotetrazolium ganglioside. The content of such lipids is preferably from about 1% to about 10% (molar ratio) relative to the total lipid material of the lipid particles 200.

[0110] The lipid may also contain lipids, such as lipids with relatively low toxicity to modulating toxicity; lipids having functional groups for binding ligands to lipid particles 200; and lipids for inhibiting leakage of the encapsulated contents, such as sterols including cholesterol. Cholesterol is particularly preferred.

[0111] For example, lipid particles 200 preferably contain compounds of formula (1-01) or formula (1-02) and / or compounds of formula (2-01), DOPE and / or DOTAP, cholesterol and DMG-PEG.

[0112] The type and composition of lipids are appropriately selected, taking into account factors such as the expected acid dissociation constant (pKa) of the lipid particles 200, the size of the lipid particles 200, the type of encapsulated contents, and the stability in the cells in which the lipid particles are introduced. For example, in order to obtain the desired composition of the lipids constituting the lipid particles 200, the composition of the lipids contained in the first solution can be set to the same ratio as the desired composition.

[0113] The organic solvent in the first solution is, for example, ethanol, methanol, isopropanol, diethyl ether, chloroform, benzene, acetone, etc. The concentration of lipids in the organic solvent is preferably, for example, 0.1% to 0.5% (by weight).

[0114] The second solution can be prepared by containing drug 202 in an aqueous solvent and mixing drug 202 with the aqueous solvent.

[0115] Aqueous solvents include water, saline solutions such as physiological saline, glycine aqueous solution, buffer solutions, etc., and are selected according to the type of drug 202.

[0116] Drug 202 is not particularly limited and may be, for example, a nucleic acid. Nucleic acid drug 202 may be, for example, a nucleic acid containing DNA, RNA and / or other nucleotides, and may be, for example, mRNA of a specific gene, DNA encoding a gene, DNA containing a gene expression cassette or vector, etc., wherein the gene expression cassette contains a gene and other sequences, such as a promoter for expressing the gene.

[0117] In the case where drug 202 is a nucleic acid, the nucleic acid can be treated with reagents such as those that promote the encapsulation of nucleic acids in lipid particles and / or those that promote the expression of genes contained in the nucleic acid in cells before the preparation of the second solution. For example, such treatment can be performed by mixing a solution containing nucleic acid and a solution containing the reagent. Prior to treatment, foreign matter can be removed from each of these solutions through the flow channel structure of the embodiment.

[0118] Drug 202, which is not a nucleic acid, contains, for example, proteins, peptides, amino acids, another organic compound, or an inorganic compound as its active ingredient. Drug 202 may be, for example, a therapeutic or diagnostic drug for a disease. However, drug 202 is not limited to these and may be any substance as long as it can be encapsulated in lipid particles 200.

[0119] Drug 202 may also contain, for example, pH adjusters, osmotic pressure regulators, and / or reagents such as pharmaceutical active agents (if necessary). pH adjusters are, for example, organic acids, such as citric acid and its salts. Osmotic pressure regulators are sugars, amino acids, etc. Pharmaceutical active agents are, for example, reagents that contribute to the activity of the active ingredient.

[0120] Drug 202 may contain one type of substance or may contain multiple substances. The concentration of drug 202 in the second solution is preferably, for example, 0.01% to 1.0% (by weight).

[0121] Next, the steps of foreign matter removal S1, mixing S2, granulation S3, and concentration S4 will be described. For example, [the steps can be described in the original text]. Figure 14 The flow channel structure described herein is used for foreign matter removal steps S1 to concentration steps S4. Figure 14 Part (a) describes the flow channel structures 1a and 1b for the implementation of the foreign matter removal step S1 and the two-liquid mixing flow channel structure 11 connected downstream thereto for the mixing step S2. Figure 14 Part (b) describes the granulation flow channel structure 301 having a configuration for performing the granulation step S3, and Figure 14 Part (c) describes a concentration channel structure 302 having a configuration for performing the concentration step S4.

[0122] - Foreign object removal step S1

[0123] In the foreign matter removal step S1, for example, the first solution and the second solution are allowed to flow through flow channel structures 1a and 1b, respectively. Flow channel structures 1a and 1b are not limited to... Figure 14The flow channel structures described herein may be used, and any one of the first to fifth embodiments may be used. Flow channel structures 1a and 1b need not have the same shape and may have different shapes from each other. In the case where foreign matter 6 is present in the first solution and the second solution, foreign matter 6 is captured in the shallow portions 3a and 3b by the foreign matter removal step S1, and the fluid used to remove foreign matter 6 may be supplied to the two-liquid mixing flow channel structure 11 located downstream therefrom.

[0124] - Mixing step S2

[0125] Next, mix the first and second solutions. For example, using... Figure 14 The two-liquid mixing channel structure 11 described in part (a) is used to mix the first solution and the second solution. Here, the two-liquid mixing channel structure 11 has the following characteristics: Figure 3 The second flow channel 12 and the third flow channel 13 merge to form a fourth flow channel 14. The second flow channel 12 has a shallow portion 3c at the end of the fourth flow channel, and further downstream of the fourth flow channel 14, one of the flow channels branches into two flow channel structures 15 that merge again. For example, the flow channel structures 15 are arranged in series. One, two, four or more flow channel structures 15 can be provided, and they can also be arranged in parallel. In addition, each of the two branch flow channels of the flow channel structure 15 has a shallow portion 3d and a shallow portion 3e, for example, with a shallow depth in the middle. The depth of the shallow portions 3d and 3e can be the same as the depth of the shallow portion 3c.

[0126] For example, a first solution, after removing foreign matter, flows from flow channel 1a to the second flow channel 12, and a second solution, after removing foreign matter, flows from flow channel 1b to the third flow channel 13. Thus, the two liquids merge in the fourth flow channel 14 to obtain a mixed solution. Conversely, the second solution may flow to the second flow channel 12, and the first solution may flow to the third flow channel 13. The mixed solution can be further mixed and stirred through flow channel 15.

[0127] There is no need to use a flow channel for mixing step S2, and after the foreign matter removal step, the first and second solutions can be stored in a container and mixed and stirred.

[0128] Next, in the granulation step S3, the concentration of the organic solvent in the mixed solution is reduced. For example, it is preferable to relatively reduce the concentration of the organic solvent by adding a large amount of aqueous solution to the mixed solution. For example, an aqueous solution three times the volume of the mixed solution is added. As the aqueous solution, the same aqueous solvent used in the first solution can be used. By reducing the concentration of the organic solvent, the lipids are granulated to form lipid particles 200 encapsulating the drug 202. As a result, a lipid particle solution containing lipid particles 200 is obtained.

[0129] like Figure 14As described in section (b), the granulation channel structure 301 used for the granulation step S3 is, for example, a Y-shaped channel. The upstream end of one Y-shaped branch channel 311 is connected to, for example, the downstream end of a two-liquid mixing channel structure 11, and a mixed solution is supplied from channel 311. The upstream end of another channel 312 includes, for example, an aqueous solution inlet 313, and an aqueous solution flows out from channel 312. As a result, the aqueous solution and the mixed solution are mixed in channel 314, where channels 311 and 312 converge. As a result, lipids are granulated, and lipid particles 200 containing drug 202 are formed, thereby obtaining a lipid particle solution containing lipid particles 200.

[0130] The granulation step S3 can be performed without using a flow channel, and an aqueous solution can be added, for example, to the mixed solution collected in the container.

[0131] In this way, lipid particles 200 can be produced.

[0132] -Concentration step S4

[0133] For example, concentration step S4 can be performed by removing a portion of the solvent and / or excess lipids and drug 202 from the lipid particle solution. Concentration can be performed, for example, by ultrafiltration. For ultrafiltration, an ultrafiltration filter having a pore diameter of 2 nm to 100 nm is preferably used, for example. Amicon Ultra-15 (Merck), etc., can be used as filters. By performing concentration step S4, a lipid particle solution with high purity and high concentration can be obtained. After concentration, the concentration of lipid particles 200 in the lipid particle solution is preferably about 1 × 10⁻⁶. 13 Cells / mL to 5×10 13 per mL.

[0134] like Figure 14 As described in part (c), the concentration channel structure 302 for performing the concentration step S4 includes a channel 321 and a filter 322 disposed on the wall surface of the channel 321. The upstream end of the channel 321 is connected to, for example, a channel 314 of the granulation channel structure 301.

[0135] Filter 322 replaces, for example, a portion of the wall surface of flow channel 321. Any of the ultrafiltration filters described above can be used as filter 322.

[0136] For example, as the lipid particle solution flows from channel 314 to channel 321, excess material, excess solvent, etc., pass through filter 322 and are discharged outside channel 321, while lipid particles 200 remain in channel 321 and flow downstream. Thus, the lipid particle solution is concentrated. The downstream end of channel 321 may include a discharge port 323 for collecting the concentrated lipid particle solution, or may be connected to a tank for collecting the lipid particle solution.

[0137] There is no need to use a flow channel for the concentration step S4, and a filter can be used, for example, to filter the lipid particle solution collected in the container.

[0138] Additionally, the method for using lipid particles in the implementation scheme may also include treatments (if necessary) to improve the quality of the lipid particles 200. Quality improvements may include, for example, preventing leakage of drug 202 from the lipid particles 200, increasing the amount of drug 202 encapsulated in the lipid particles 200, increasing the ratio of lipid particles 200 encapsulating drug 202 (encapsulation ratio), reducing and preventing flocculation of the lipid particles 200, and / or reducing lipid particle size changes. For example, treatments for cooling the lipid particle solution may be performed. Such treatments may also be performed using flow channels.

[0139] Each of the flow channels described above is, for example, a microchannel. The flow of fluid in the flow channels, the injection of fluid into the flow channels, the removal of fluid from the tank and / or the containment of lipid particle solutions in the container can be performed automatically, for example, by a retrieval mechanism or pump constructed and controlled.

[0140] In the method for manufacturing lipid particles of the embodiment, it is not always necessary to include a concentration step S4, and the method for manufacturing lipid particles of the embodiment may include at least a foreign matter removal step S1, a mixing step S2, and a granulation step S3.

[0141] According to the method for manufacturing lipid particles in the embodiment, because the flow channel structure of the embodiment can be used to remove foreign matter 6, the adverse effects of foreign matter on the mixing step S2, granulation step S3, and concentration step S4 are reduced. As a result, high-quality lipid particles 200 can be manufactured more efficiently. Example

[0142] The following describes an embodiment in which the flow channel structure of the second implementation scheme is manufactured and used.

[0143] manufacture Figure 15 The flow channel structure is described in the diagram. The flow channel structure has a Y-shaped configuration where two flow channels merge into one. Before merging, one of the two channels has a foreign matter removal structure, while the other channel does not. The foreign matter removal structure has… Figure 16 The shape described in part (a) is the shape of the wide shallow portion 3a of the second embodiment. The depth of the shallow portion 3a is 1 / 3 of the depth of each of the front and rear flow channels, and the width of the shallow portion 3a is three times the width of each of the front and rear flow channels. Additionally, the flow channels after merging have a stepped structure portion, said structure portion having... Figure 16The structure is described in section (b). The stepped structure section has a configuration in which the flow channel branches into two and then merges again, and each of the two branch flow channels has shallow portions 3d and 3e with shallow depths in the middle therebetween. The depths of the shallow portions 3d and 3e are 1 / 3 of the depths of the front and rear flow channels. Note that the arrows in the attached figures indicate the direction of fluid flow.

[0144] First, fluid containing fibrous foreign matter 6 flows from a first supply port of a flow channel having a foreign matter removal structure, and images of the foreign matter removal structure and the stepped structure are captured. Next, the flow channel is cleaned to remove foreign matter 6 from the stepped structure, and the same fluid flows from a second supply port of a flow channel without a foreign matter removal structure, and an image of the stepped structure is captured.

[0145] Figure 16 Part (a) is a photograph illustrating the foreign matter removal structure section as fluid flows from the first supply port. This photograph shows that a large number of foreign objects 6 are captured in the foreign matter removal structure section. Additionally, in Figure 16 Part (b) shows a photograph of the stepped structure at this point. This photograph shows a small amount of foreign object 6 reaching the stepped structure. Figure 16 Part (c) is a photograph illustrating the stepped structure section as fluid flows from the second supply port. In this photograph, [the text continues with...] Figure 16 Compared to part (b), a large number of foreign objects 6 reach the stepped structure section. Note that the black circles seen in the flow channel are bubbles mixed after the test and are unrelated to the experimental results.

[0146] The results above demonstrate that by providing a foreign matter removal structure, the amount of foreign matter 6 flowing downstream of the flow channel structure capable of capturing foreign matter 6 is reduced.

[0147] While some embodiments have been described, these embodiments are shown by way of example only and are not intended to limit the scope of the invention. Indeed, the novel embodiments described herein can be implemented in many other forms; furthermore, various omissions, substitutions, and changes can be made to the form of the embodiments described herein without departing from the spirit of the invention. The appended claims and their equivalents are intended to cover these forms or modifications that fall within the scope and spirit of the invention.

Claims

1.A flow passage structure which removes foreign matter in each of two liquids and mixes the two liquids, the flow passage structure comprising: two flow passage structures for removing foreign matter, including a first flow passage, wherein the first flow passage has a first region having a shallower depth than that of another region; and a two-liquid mixing flow passage having a shape in which a second flow passage and a third flow passage merge into a fourth flow passage; a second flow passage connected downstream of one of the flow passage structures for removing foreign matter, and a third flow passage connected downstream of the other flow passage structure for removing foreign matter, and the second flow passage has a second region in which the second flow passage has a shallower depth than that of the fourth flow passage at one end of the second flow passage close to the fourth flow passage, wherein the depth of the first region is equal to or smaller than the depth of the second region. 2.The flow passage structure according to claim 1, further comprising a branching and re-merging passage downstream of the fourth flow passage, wherein the branching and re-merging passage having a branching portion that divides an upstream flow passage into two flow passages, and a re-merging portion that connects to each other downstream of the two branched flow passages. 3.The flow passage structure according to claim 1 or 2, wherein the first flow passage is a cavity formed inside the flow passage structure. 4.The flow passage structure according to claim 1 or 2, wherein the first region has a flow passage width wider than that of the other region. 5.The flow passage structure according to claim 4, wherein the flow passage width of the first region is set so that the average flow velocity of the fluid in the first region is equal to or smaller than the flow velocity when the fluid is supplied to the first flow passage when the fluid flows to the first flow passage. 6.The flow passage structure according to claim 1 or 2, wherein the first flow passage has a shape bent at a right angle in front of the first region. 7.The flow passage structure according to claim 1 or 2, wherein the first flow passage is curved in an arc shape, and one flow passage wall of the first flow passage has a curvature larger than that of another flow passage wall facing said one flow passage wall. 8.The flow passage structure according to claim 1 or 2, further comprising a structure for filtering foreign matter provided on the first region. 9.The flow passage structure according to claim 8, wherein the structure for filtering foreign matter has a plurality of elongated protrusions arranged at intervals in parallel with each other in the flow direction in the first flow passage. 10.The flow passage structure according to claim 8, wherein the structure for filtering foreign matter has a plurality of cylindrical protrusions extending in the depth direction of the first flow passage. 11.The flow passage structure according to claim 1 or 2, wherein the first flow passage has a plurality of first regions. 12.The flow passage structure according to claim 1 or 2, wherein the depth and width of the other region of the first flow passage are 0.1 mm to 3 mm.

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