Microfluidic Mixers and / or Separators

Abstract

A device and method of use for mixing at least two substances to form a pharmaceutical conjugate are provided. A microfluidic device may include at least one inlet channel, a microfluidic channel having a first portion fluidly connected to the at least one inlet channel, and at least one outlet channel fluidly connected to a second portion of the microfluidic channel, the microfluidic channel having a plurality of dimples extending away from an axis of the microfluidic channel. The at least one inlet channel includes a first inlet channel and a second inlet channel, and / or the at least one outlet channel includes a first outlet channel and a second outlet channel. In some embodiments, the plurality of dimples may be configured to separate nanoparticles of different sizes into the first outlet channel and the second outlet channel.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to U.S. Provisional Patent Application No. 63 / 378,230, filed October 3, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to devices, systems, and methods of use for mixing at least two substances to form pharmaceutical conjugates and / or isolating monodisperse nanoparticles. [Background technology]

[0003] Recent developments in immunology include the newly approved messenger RNA-lipid nanoparticle (mRNA-LNP) vaccine. Messenger RNA (mRNA) technology has the advantage of being able to rapidly adapt to new antigen designs by modifying the mRNA sequence without the need to overhaul the chemical and manufacturing controls (CMC) of vaccine production. However, mRNA provided alone is not easily absorbed or effectively delivered to human immune cells, has unstable chemical and physical properties, and is therefore ineffective for use as a vaccine. Recent developments have shown that mRNA absorption and stability can be increased to effective levels when encapsulated within a lipid nanoparticle (LNP) vector.

[0004] Preparation of mRNA-LNP vaccines is achieved by mixing lipid-dissolved ethanol with RNA in a buffer solution under strictly controlled conditions. Such mixing is typically performed in laboratories using various equipment, but these are often unsuitable for large-scale distribution due to their low durability, high cost, high complexity, poor lot-to-lot consistency, and / or high batch-to-batch variability. Summary of the Invention

[0005] The inventors have recognized that mRNA-LNP vaccines have a limited shelf life at room temperature. To extend their shelf life, mRNA-LNP vaccines must be stored at extremely low temperatures (typically -20 to -80 degrees Celsius). This is problematic because low-temperature distribution is expensive and logistically complex. In addition, there is a risk that mRNA-LNP vaccines will be wasted if, for example, the low-temperature environment at any stage of the distribution chain becomes inoperable.

[0006] Non-messenger RNA drugs, such as RNAi, siRNA, and other oligonucleotides, can also be formulated into lipid nanoparticle compositions (RNA-LNPs). RNA-LNP drugs can be chemically modified to improve their stability and shelf life at room temperature (such chemical modifications are not possible with mRNA-LNP technology, which requires interaction with cellular proteins to function properly). Chemical modification of RNA-LNPs can be difficult and expensive to achieve, but is nonetheless often preferred to avoid the significant distribution costs associated with unmodified RNA-LNP drugs, which must also be kept at very low temperatures, as well as the difficulties associated with managing drug efficacy over time due to their limited molecular half-life.

[0007] In short, the low temperature requirement presents a major challenge for distribution and development. Other problems associated with known systems for producing nanoparticle compositions include limited scalability, usability, and / or reliability. One or more of the aforementioned needs are met by various embodiments as disclosed herein.

[0008] A first aspect of the present disclosure relates to a microfluidic device having at least one inlet channel, a microfluidic channel having a first portion fluidly connected to the at least one inlet channel, and at least one outlet channel fluidly connected to a second portion of the microfluidic channel, the microfluidic channel having a plurality of dimples extending away from an axis of the microfluidic channel.

[0009] The microfluidic device may have one or more of the following features: The at least one inlet channel may include a first inlet channel and a second inlet channel; The at least one outlet channel may include a first outlet channel and a second outlet channel; The plurality of dimples may be arranged circumferentially around the microfluidic channel; The plurality of dimples may be arranged in longitudinally overlapping sets; The plurality of dimples may include a first set of dimples arranged longitudinally along the microfluidic channel and a second set of dimples arranged longitudinally along the microfluidic channel, the first set of dimples and the second set of dimples being laterally offset, and the first set of dimples and the second set of dimples being configured to separate nanoparticles by size; The first set of dimples may have a first width or diameter, and the second set of dimples may have a second width or diameter of a second size, the first width or diameter being different from the second width or diameter. The first width or diameter may be about 50 μm to about 200 μm, and the second width or diameter may be about 200 μm to about 500 μm. The at least one outlet channel may include a first outlet channel and a second outlet channel, and the first set of dimples may be arranged to guide nanoparticles of a first size into the first outlet channel, and the second set of dimples may be arranged to guide nanoparticles of a second size into the second outlet channel. The at least one outlet channel may include a third outlet channel, and the plurality of dimples may include a third set of dimples arranged longitudinally along the microfluidic channel. The third set of dimples may be configured to guide nanoparticles of a second size into the third outlet channel.

[0010] A second aspect of the present disclosure relates to a microfluidic device having a plurality of inlet channels, a microfluidic channel having a first portion fluidly connected to the plurality of inlet channels, and a plurality of outlet channels fluidly connected to a second portion of the microfluidic channel, the microfluidic channel having a plurality of dimples extending away from an axis of the microfluidic channel.

[0011] The microfluidic device may have one or more of the following features: the plurality of outlet channels may include a first outlet channel, a second outlet channel, and a third outlet channel; the plurality of dimples may include a first set of dimples arranged to guide nanoparticles of a first size to the first outlet channel, a second set of dimples arranged to guide nanoparticles of a second size to the second outlet channel, and a third set of dimples arranged to guide nanoparticles of the second size to the second outlet channel.

[0012] A third aspect of the present disclosure relates to a method for fabricating a microfluidic channel. The method may include injecting one or more elastomeric materials into a mold cavity around a core pin having an elongated shaft with multiple protrusions extending from an axis of the core pin, forming a component including a microfluidic channel with multiple dimples from the one or more elastomeric materials, and removing the core pin from the component.

[0013] The method may include one or more of the following features. The method may further include removing the component and the central core from the mold cavity before removing the core pin from the component. The one or more elastomeric materials may include silicone, rubber, and / or a thermoplastic elastomer. Removing the core pin from the component may be performed using a compressed air ejector system. Removing the core pin from the component may be performed by sliding the component away from the core pin. The protrusion may be spherical. [Brief explanation of the drawings]

[0014] Particular embodiments of the present disclosure are described, by way of example only, in the following detailed description and with reference to the accompanying drawings. [Figure 1] FIG. 1 illustrates a side view of an exemplary system according to the present disclosure. [Figure 2] 2 illustrates an exemplary microfluidic channel of the microfluidic device of FIG. 1. [Figure 3] 3 illustrates an exemplary method for fabricating the microfluidic device of FIGS. 1 and 2. [Figure 4] 4 illustrates an exemplary core pin used in the method of FIG. 3. [Figure 5] 2 shows a second embodiment of the microfluidic device of FIG. 1.

[0015] The same reference numbers are used in the drawings and the following detailed description to refer to the same or similar parts. DETAILED DESCRIPTION OF THE INVENTION

[0016] A microfluidic device for connecting one or more fluid containers for mixing first and second substances to produce a pharmaceutical conjugate is provided. The microfluidic device includes a first port or connector member configured to connect to the first container, a second port or connector member configured to connect to the second container, and a third port or connector member configured to connect to a receiving container. The microfluidic device further includes a microfluidic channel extending from a first portion in fluid communication with the first and second ports to a second portion in communication with the third port. The microfluidic device may include obstacles configured to generate chaotic mixing of the fluids, for example, allowing charged nanoparticles to self-assemble in a predetermined alignment and structure based on their chemical makeup, charge, and / or shape. The obstacles may be created by dimples in the flow channel that, together with the flow channel, form a vortex channel when a specific flow rate is achieved. The size, shape, orientation, and patterning of the obstacle geometry may be specifically and purposefully designed to generate flow channels with different chaotic and turbulent flows for different applications. In some embodiments, the microfluidic device may additionally or alternatively be configured to separate the formed nanoparticles by size due to the geometry of obstacles in the channel. The microfluidic device may create targeted turbulence created by the geometry of the obstacles, where nanoparticles of different sizes will migrate to specific flow regions of the microfluidic channel, and the flow characteristics of the channel will essentially separate the nanoparticles by size.

[0017] FIG. 1 shows a system including a first container 20, a second container 40, a receiving container 60, and a microfluidic device 100. In some embodiments, the system may further include a first storage container 80 containing a first substance or component and a second storage container 82 containing a second substance or component. The first container 20 may be configured to transfer the first substance from the first storage container 80 to the microfluidic device 100. The second container 40 may be configured to transfer the second substance from the second storage container 82 to the microfluidic device 100. The microfluidic device 100 may include at least one pathway configured to mix the first and second substances and transfer the pharmaceutical complex to the receiving container 60. The system may comprise a kit of at least one or all of the first container 20, the second container 40, the receiving container 60, the microfluidic device 100, the first storage container 80, and / or the second storage container 82. The system and / or kit may further include one or more vial adapters 70 for fluid transfer to or from one or more of the receiving container 60, the first storage container 80, and / or the second storage container 82. The kit components may include packaging for shipping to an end user.

[0018] The first container 20 may be a variable volume container, such as a first syringe, configured to at least temporarily store and / or transfer a first substance from the first storage container 80 to the microfluidic device 100. The second container 40 may be a variable volume container, such as a second syringe, configured to store and transfer a second substance from the storage container 82 to the microfluidic device 100. The first syringe 20 may include a first syringe body 22 and a first plunger rod 24, and the second syringe 40 may include a second syringe body 42 and a second plunger rod 44. Each syringe body 22, 42 may have a syringe barrel extending longitudinally from a proximal end to a distal end. Each syringe body 22, 42 may have a syringe tip at the distal end and a flange at the proximal end. The syringe barrel may be tubular with an inner surface extending longitudinally to define a chamber. The chambers may be configured to receive, store, and / or mix a substance for dispensing through the distal openings of the syringe tips. The first plunger rod 24 may have a first flange 25 at its proximal end, and the second plunger rod 44 may have a second flange 45 at its proximal end. The syringe tip of the first syringe body 22 may include a first connector 26 for engaging an external device, such as a syringe needle, a container, and / or the microfluidic device 100. The syringe tip of the second syringe body 42 may include a second connector 46 for engaging the same or a different external device, such as a syringe needle, a container, and / or the microfluidic device 100. Each connector 26, 46 may further include a male Luer connector including the syringe tip and a threaded sleeve around the tip. The syringe tips may be tapered to guide fluid flow into an external device (e.g., microfluidic device 100), and the sleeves may have internal threads configured to secure the syringes 20, 40 to their respective external devices (e.g., microfluidic device 100). The containers 20, 40 may be any conventional syringes and / or reciprocating pumps suitable for use in a pharmaceutical environment.

[0019] The flanges 25, 45 may be actuated either by being pulled to create a negative pressure to draw the substance into the chamber and / or by being pushed to create a positive pressure to expel the substance from the chamber. At least a portion of the first syringe 20 and the second syringe 40 may be integrally or releasably connected to enable coordinated manipulation and / or actuation of the first syringe 20 and the second syringe 40. For example, the system may further include a barrel holder (not shown) having a first lumen configured to receive the first syringe body 22 and a second lumen configured to receive the second syringe body 42 so that the first syringe 20 and the second syringe 40 may be manipulated together. Each of the first and second lumens may be closed or formed by a C-shaped wall configured to snap around the respective syringe body 22, 42. The barrel holder may secure the syringe bodies 22, 42 in a substantially parallel arrangement. The system may further include a plunger clip configured to translate the plunger rods 24, 44 together through the syringe bodies 22, 42 to push and / or pull the material with the same longitudinal translation. For example, the plunger clip may be configured to attach to the flanges 25, 26 and may have grooves configured to releasably receive the flanges 25, 26. Embodiments of barrel holders and / or plunger clips are further discussed in U.S. Patent Nos. 5,104,375, 6,840,921, and 8,240,511, the entire disclosures of which are incorporated herein by reference.

[0020] The receiving vessel 60 may be a fixed volume vessel, such as a vial, that can be attached to the microfluidic device 100 using a vial adapter 70. The vial 60 may include a vial bottle 62 having a crown and a neck enclosing a chamber. The chamber may be sealed by a drug vial seal at the crown, which is circumferentially attached by an aluminum band. The vial adapter 70 may have a transverse top wall 72, a connector 74 extending upward from the top wall 72, and a skirt 76 extending downward from the top wall 72. The connector 74 may be a female Luer connector including external threads for screw-thread engagement with a male Luer lock connector, such as the connector of the microfluidic device 100. The skirt 76 may be for telescopic attachment over the crown and / or neck of the vial 60. The skirt 76 may enclose a cannula (not shown) extending downward from the top wall 72 and configured to pierce a vial stopper. The cannula may have a lumen that fluidly communicates with the chamber of the vial bottle 62 when it punctures the vial stopper. The vial adapter 70 may be vented to draw air into the container 60 and facilitate drawing fluid through the system. Further discussion of embodiments of the container 60 and / or vial adapter 70 is provided in U.S. Pat. Nos. 8,753,325 and 9,943,463, the entire disclosures of which are expressly incorporated herein by reference. The receiving container 60 may be initially empty and configured to receive materials dispensed from the first and second containers 20, 40 and mixed within the microfluidic device 100. After the first and second components are introduced into the microfluidic device 100, the resulting pharmaceutical complex may be stored in the receiving container 60.

[0021] However, in some embodiments, the receiving container 60 may be a variable volume container, such as a syringe, and one or both of the first and second containers 20, 40 may be fixed volume containers, such as vials. Further discussion of such embodiments is provided in U.S. Patent Application Publication No. 2023 / 0105059, the entire disclosure of which is expressly incorporated herein by reference.

[0022] The first storage container 80 and / or the second storage container 82 may have a structure similar to the receiving container 60, the discussion of which is expressly incorporated herein in its entirety. For example, each of the first and second storage containers 80, 82 may be a fixed volume container enclosing a chamber and having a crown 84 and a neck 85. The chamber may be sealed by a drug vial seal 86 at the crown 84, which is circumferentially attached by an aluminum band. Each of the first and second storage containers 80, 82 may be attached to the vial adapter 70, as discussed with reference to the receiving container 60.

[0023] The first substance in first storage container 80 may be an aqueous solution. The aqueous solution may be any aqueous buffer solution that can be used to dissolve nucleic acids. For example, in some embodiments, the aqueous solution may be a solution of 20 mM citrate and 300 mM sodium chloride and may have a pH ranging from 3 to 6. In some embodiments, the aqueous solution may be 20 mM phosphate buffer (PBS) at pH 7. In some embodiments, the aqueous solution may be a solution of 5 mM to 25 mM sodium acetate buffer at a pH range of 4 to 6.

[0024] The second substance in the second storage container 82 may be a lipid solution having a composition comprising, in whole or in part, an organic solvent containing a lipid or a mixture of lipids. The lipid solution may comprise clinical-grade lipids solubilized in an organic alcohol solution (e.g., ethanol). In some embodiments, the lipid solution may be at least a 25% alcohol solution. In some embodiments, the lipid solution may be at least a 40% alcohol solution. In some embodiments, the lipid solution may be at least a 60% alcohol solution. The alcohol solution is preferably an ethanol solution. Providing lipids in such an increased alcohol concentration may allow the lipids in the alcohol solution to withstand dilution by a reconstitution agent without affecting the quality of the resulting pharmaceutical conjugate. The lipid composition in the ethanol solution may be composed of ionizable or cationic lipids or synthetic lipids, structured lipids, PEG-lipids or derivatives thereof, and cholesterol or derivatives thereof. However, the second substance may also comprise other nanoparticle-forming solutions.

[0025] A therapeutic agent may be carried in at least one of the first substance and / or the second substance. In a preferred embodiment, the therapeutic agent is carried in the first substance. The therapeutic agent may include a nucleic acid, a drug, a protein, an oligonucleotide, etc., including a gene editing complex. The nucleic acid may include RNA and / or DNA. The RNA may be in the form of an oligonucleotide RNA, tRNA (transfer RNA), snRNA (small nuclear RNA), rRNA (ribosomal RNA), mRNA (messenger RNA), antisense RNA, siRNA (small interfering RNA), shRNA (short hairpin RNA), ncRNA (non-coding RNA), an aptamer, a ribozyme, a chimeric sequence, or derivatives of these groups. The gene editing complex may include a gRNA (guide RNA), a cas9 protein, an mRNA or DNA encoding the cas9 protein, or a CRISPR-cas9gRNA complex. The DNA may be in the form of antisense, plasmid DNA, a portion of plasmid DNA, pre-condensed DNA, a polymerase chain reaction (PCR) product, a vector (P1, PAC, BAC, YAC, artificial chromosome), an expression cassette, a chimeric sequence, chromosomal DNA, or derivatives of these groups.

[0026] In some embodiments, the therapeutic agent may be stored in a dehydrated and / or lyophilized state and reconstituted in an aqueous solution to form the first substance before being introduced into the microfluidic device 100. In this case, first storage container 80 may hold the dehydrated therapeutic agent, and first container 20 may hold the aqueous solution. The aqueous solution may then be introduced from first container 20 into first storage container 80 to reconstitute the therapeutic agent. The first solution containing the therapeutic agent may then be introduced into first container 20 and introduced into the adapter.

[0027] The first substance (with the therapeutic agent in a lyophilized state or as a solution) and the second substance may be adapted for transport and medium- or long-term storage at room temperature. Thus, the system and microfluidic device 100 disclosed herein may alleviate the obstacles associated with storing and transporting RNA-LNP complexes at very low temperatures. Furthermore, the microfluidic device 100 may be easy to use in clinical settings.

[0028] The first and second substances may be mixed using the microfluidic device 100 as discussed herein. Mixing may produce a liposome former, which entraps the therapeutic agent simultaneously with liposome formation. Electrostatic interactions between a negatively charged therapeutic agent (e.g., a nucleic acid) and a positively charged cationic lipid may result in encapsulation, forming a pharmaceutical complex. The pharmaceutical complex may be a monodisperse lipid nanoparticle (LNP). Thus, the system and microfluidic device 100 may be used to form a ready-to-inject RNA-LNP (e.g., mRNA-LNP) complex by mixing components of an aqueous solution containing RNA and a lipid solution. Considering the specific example of forming an mRNA-LNP pharmaceutical complex, the complex may be formed by mixing a first substance containing mRNA (or RNA) from the first container 20 with a second substance in a lipid solution from the second container 40.

[0029] The first and second storage containers 80, 82 may be the same or different sizes depending on the intended mixture. Accordingly, any reference herein to two storage containers should be interpreted as including three or more storage containers. It will be understood that where three or more components are to be mixed, three or more containers may be provided, each containing at least one component. Furthermore, any number of components may be provided unmixed in a single container. In some embodiments, the first container 20 and the second container 40 may be pre-filled with the respective substances, e.g., embodied as pre-filled syringes, and the first and second storage containers 80, 82 may be omitted.

[0030] The microfluidic device 100 may define a first port 102 configured to connect to the syringe connector 26 of the first container 20 and a second port or connector member 104 configured to attach to the syringe connector 46 of the second container 40. The first port 102 and the second port 104 may be connected to a first top portion of a mixing member 106. A third port or connector member 108 may be connected to a second bottom portion of the mixing member 106.

[0031] The first port 102 may be configured to be received by the first syringe connector 26 and may have external threads 103 configured to mate with the internal threads of the first connector 26. Similarly, the second port 104 may be configured to be received by the second connector 46 and may have external threads 105 about the second tubular member 108 configured to mate with the internal threads of the second syringe connector 46. For example, the ports 102, 104 may be female Luer connectors and the connectors 26, 46 of the containers 20, 40 may be male Luer connectors. However, the ports 102, 104 may additionally or alternatively connect to the containers 20, 40 with other types of connections, such as a snap fit, a friction fit, and / or a press fit. The microfluidic device 100 may be configured to connect to any number of first and second containers 20, 40, and the microfluidic device 100 may therefore have an equal number of ports 102, 104 for connecting to each of the containers 20, 40. Additionally, one or more of the ports 102, 104 may include a one-way valve (not shown) to allow fluid flow from the containers 20, 40 to the microfluidic device 100 and to limit or substantially prevent fluid flow from the microfluidic device 100 back to the respective container 20, 40.

[0032] The first port 102 may define a first inlet channel 110, and the second connector member 104 may define a second inlet channel 112. In some embodiments, the first inlet channel 110 may be configured to receive a tip of the first syringe 20 to fluidly connect the chamber of the first syringe body 22 to the first inlet channel 110, and the second inlet channel 112 may be configured to receive a tip of the second syringe 40 to fluidly connect the chamber of the second syringe body 42 to the second inlet channel 112. In some embodiments (not shown), the first port 102 and the second port 104 may extend substantially parallel to one another to facilitate coordinated actuation of the syringes 20, 40. The first inlet channel 110 and the second inlet channel 112 may extend to the mixing member 106 at an angle. The angle may be at least 90 degrees, and in some embodiments may be from about 120 degrees to about 160 degrees. For example, the mixing element 106, the first port 102, and the second port 104 may form a Y-shaped portion of the microfluidic device 100. The mixing element 106 may define a microfluidic channel 114.

[0033] FIG. 2 illustrates an embodiment of a microfluidic channel 114. The microfluidic channel 114 may include a path extending along the longitudinal axis of the mixing body 106. The path of the microfluidic channel 114 may include a plurality of dimples 120 formed in the mixing body 106 of the microfluidic device 100. The microfluidic channel 114 may extend along the longitudinal axis of the microfluidic body 106, and the dimples 120 may extend radially outward from the microfluidic channel 114 and be recessed in the mixing body 106. Thus, for this configuration, the path of fluid flowing through the microfluidic channel 114 may be serpentine, extending in and out of the dimples 120. The serpentine path may meander from the longitudinal axis of the mixing body 106. The geometry of this fluid obstacle defined by the dimples 120 may create intentionally chaotic flow that induces vortices and turbulence to mix the fluidic substances, improving mixing and producing consistently sized pharmaceutical conjugates.

[0034] As shown in FIG. 2 , the dimples 120 may be arranged three-dimensionally and continuously around the microfluidic channel 114 along the longitudinal axis. Thus, the dimples 120 may be formed to surround the microfluidic channel 114 (e.g., above, below, laterally, or circumferentially therearound), allowing mixing to occur using the entire microfluidic channel 114. In some embodiments, the dimples 120 may be formed along the entire length of the microfluidic channel 114. This configuration may be more efficient than a two-dimensional channel and provide predictable fluid flow through the microfluidic channel 114. The size, shape, orientation, location, and pattern of this fluid obstacle geometry configuration may be tailored to enable specific chaotic mixing that results in predictable flow patterns. The dimples 120 may be arranged circumferentially around the microfluidic channel 114 in longitudinally staggered or angularly offset sets such that longitudinally adjacent dimples 120 are not aligned along their central axes. These sets may be formed by a first set 120a and a second set 120b of dimples that are rotationally offset and alternate along the longitudinal axis of the microfluidic channel 114. The alternation allows adjacent dimples 120 to be longitudinally closer and / or overlap, thereby increasing the density of the dimples 120. The dimples 120 may have a circular cross-section and / or a width or diameter w of about 200 μm to about 500 μm. For example, the dimples 120 may be circular with a diameter of about 280 μm to about 325 μm. The width or diameter of the dimples 120 may be substantially uniform based on manufacturing tolerances. The longitudinally aligned dimples 120 may be separated by a (center-to-center) distance d of about 500 μm to about 800 μm. The dimples 120 may provide a variable width or diameter of the microfluidic channel 114. The microfluidic channel 114 may have a minor width w1 of about 400 μm to about 600 μm and a major width w2 of about 600 μm to about 800 μm. Further discussion of dimple embodiments is provided in U.S. Patent Application Publication No. 2023 / 0105059.

[0035] Returning to FIG. 1 , the microfluidic device 100 may have a third port or connector member 108 at the bottom of the mixing member 106. In some embodiments, the third connector member 108 may include a tip configured to attach to the receiving vessel 60 via the vial adapter 70. In some embodiments, the third connector member 108 may have a sleeve in the form of a male Luer connector (not shown). The tip may have an outlet channel 125 in communication with a second portion or bottom of the microfluidic channel 114. The tip may be received in the connector 74 of the vial adapter 70, and the sleeve may be threadably connected to an outer surface of the connector 74 with a Luer connection. The third connector member 108 may be a male Luer connector configured to connect to the female Luer connector of the vial adapter 70. However, the connector member 108 may additionally or alternatively connect to the third vessel 60 with other types of connections, such as a snap fit and / or a press fit. The outlet channel 125 may provide a passage for the mixed composition from the mixing chamber 124 to the receiving vessel 60 .

[0036] The microfluidic device 100 may be formed from a polymer, metal, and / or glass. In a preferred embodiment, the microfluidic device 100 may be formed (e.g., through injection molding or three-dimensional printing) as a single, integral part including the first port 102, the second port 104, the mixing member 106, the tubular member 129, and / or the connector member 108. Alternatively, the microfluidic device 100 may be formed from two parts (e.g., halves) secured or fused together, each of which may be metal, polymer, or glass. A low surface energy material may be used for at least a portion of the microfluidic device 100 to increase the ease with which the mixing fluids flow through the microfluidic device 100. For example, the microfluidic device 100 may be formed from or coated with a low surface energy material such as ethylene tetrafluoroethylene (ETFE). Other low surface energy materials, such as fluoropolymer materials other than ETFE, may also be used. Alternatively, at least one pathway may be treated to reduce its surface energy. Forming the sides of the microfluidic channel 114 of a low surface energy material may reduce loss of components across the microfluidic channel 114 during use, and therefore may allow the microfluidic device 100 to operate more efficiently. While the low surface energy material may provide additional benefits in some embodiments, it is an optional feature of the present disclosure. In some embodiments, as discussed below, the microfluidic device 100 may additionally or alternatively be formed of an elastomer, such as silicone, rubber, and / or a thermoplastic elastomer.

[0037] 3 illustrates a method 1000 for forming a microfluidic device 100 through injection molding, and FIG. 4 illustrates an embodiment of a core pin 200 that may be used in the method 1000. The method 1000 and core pin 200 may address shortcomings in the fabrication of three-dimensional internal components, such as the microfluidic channels 114, of the microfluidic device 100. The method 1000 may fabricate the microfluidic device 100 in a single, integral piece through injection molding. The method 1000 may eliminate manufacturing limitations and facilitate removal of the core pin 200 during fabrication of uniquely designed geometries by utilizing an elastomeric material for at least one of the core pin 200 and / or the microfluidic device 100.

[0038] In step 1002, the core pin 200 may be inserted into a cavity of a mold (not shown). The mold may be formed from two releasably attached housing members that form the cavity. As shown in FIG. 4 , the core pin 200 may have an elongated shaft 202 and may have a plurality of protrusions 204 on an outer surface of the elongated shaft 202. The protrusions 204 may have a spherical shape and be positioned along the elongated shaft 202 to correspond to the desired placement of the dimples 120. In some embodiments, the core pin 200 may be made of an elastomer, such as silicone, rubber, and / or a thermoplastic elastomer.

[0039] In step 1004, one or more materials may be injected in liquid form into the cavity and around the core pin 200. In some embodiments, the one or more materials may include an elastomer, such as silicone, rubber, and / or a thermoplastic elastomer. The one or more materials may be melted as they are injected to conform around the core pin 200 within the cavity.

[0040] In step 1006, a component including a microfluidic channel with a plurality of dimples may be formed from one or more materials. The component may be formed by cooling the one or more materials. The one or more materials may undergo crosslinking and / or vulcanization to form a component such as the microfluidic device 100. The one or more materials may form the microfluidic channel 114 along the shaft 202, and the dimples 120 are formed around the protrusions 204 to form the desired obstruction geometry.

[0041] In step 1006, the injection molded component, such as the microfluidic device 100, may be removed from the mold cavity. The core pin 200 may be removed from the microfluidic channel 114 of the microfluidic device 100. The flexibility of the elastomeric material of the microfluidic device 100 and / or the core pin 200 may allow the core pin 200 to be withdrawn from the microfluidic device 100 without removing the dimple 120 from the microfluidic channel 114. In some embodiments, the core pin 200 may be removed from the microfluidic device 100 using an air ejector system in the mold assembly that applies pressure to release the core pin 200 from the microfluidic device 100.

[0042] 5 illustrates a second embodiment of a microfluidic device 200 that may be implemented in system 10. Microfluidic device 200 may include a first inlet channel 210 configured to receive a first substance or component, and a second channel 212 configured to receive a second substance or component. In some embodiments, the first substance may be an aqueous solution and the second substance may be a lipid solution, as expressly incorporated by reference herein in its entirety and as discussed with reference to system and microfluidic device 100.

[0043] The microfluidic device 200 may include a microfluidic channel 215 having a first portion that communicates with the first inlet channel 210 and the second channel 212. The microfluidic channel 215 may be configured to mix a first substance with a second substance and / or separate formed nanoparticles by size. The microfluidic channel 215 may have a plurality of obstacles 220 configured to direct a plurality of specific, chaotic flow streams in the microfluidic channel 215. The flow streams may be generated by variable placement of the obstacles 220 to force larger nanoparticles along one or more first fluid paths and smaller nanoparticles along one or more second fluid paths. The plurality of obstacles 220 may include a first set of obstacles 220a longitudinally disposed along the first fluid path of the microfluidic channel 215. The plurality of obstacles 220 may include a second set of obstacles 220b longitudinally disposed along the first and second paths of the microfluidic channel 215. The plurality of obstacles 220 may include a third set of obstacles 220 b positioned longitudinally along a third second path of the microfluidic channel 215 .

[0044] In some embodiments, the first set of obstacles 220a may be separated by a first distance and the second set of obstacles 220b may be separated by a second distance, where the first distance is different from the second distance. The third set of obstacles 220c may be separated by a third distance, where the third distance may be the same as the second distance. In some embodiments, the first set of obstacles 220a may have a first width or diameter and the second set of obstacles 220b may have a second width or diameter, where the first width or diameter is different from the second width or diameter. The third set of obstacles 220c may have a third width or diameter, where the third width or diameter is the same as the third distance. In some embodiments, the first set of obstacles 220a may have a first depth and the second set of obstacles 220b may have a second depth, where the first depth is different from the second depth. The third set of obstacles 220c may have a third depth, which may be the same as the third depth. Thus, the obstacle geometry of obstacles 220 may generally push larger nanoparticles along one or more fluid paths and smaller nanoparticles along one or more different fluid paths.

[0045] 5, a first set of obstacles 220a may be disposed on a central portion along the centerline or axis of channel 214 and configured to guide nanoparticles into a first outlet channel 225a. A second set of obstacles 220b may be disposed on a first side portion of channel 214 and configured to guide nanoparticles into a second outlet channel 225b. A second set of obstacles 220b may be disposed on a second side portion of channel 214 and configured to guide nanoparticles into a third outlet channel 225c. The second set of obstacles 220b and the third set of obstacles 220c may be on opposite sides of the first set of obstacles 220a.

[0046] In some embodiments, the first width or diameter may be smaller than the second width or diameter and / or the third width or diameter. For example, the first width or diameter may be about 50 μm to about 200 μm, and the second width or diameter and / or the third width or diameter may be about 200 μm to about 500 μm. Additionally or alternatively, the first distance may be shorter than the second distance and / or the third distance. Additionally or alternatively, the third depth may be shallower than the second depth and / or the third depth. Thus, in some embodiments, the geometry of the obstacles in the channel 214 may continue to guide smaller particles in the center of the channel 214 into the first outlet channel 225a and push larger particles on both outer edges of the channel 214 to be guided into the second outlet channel 225b. The geometry of the obstacles may separate particles by size to produce a high-quality, collectible yield of particles of a desired size.

[0047] The size and configuration of obstacles 220 may be designed based on the desired size and source of nanoparticles. In some embodiments, the first width or diameter may be greater than the second width or diameter and / or the third width or diameter. Additionally or alternatively, the first distance may be greater than the second distance and / or the third distance. Additionally or alternatively, the third depth may be greater than the second depth and / or the third depth. In some embodiments, third set of obstacles 220c may be different from second set of obstacles 220b. In some embodiments, if two fluid paths are desired, third set of obstacles 220c and / or third outlet channel 225c may be omitted.

[0048] The microfluidic channel 215 may have a substantially rectangular cross-section with a pair of long sides extending the width of the microfluidic channel 215 and a pair of short sides extending the height of the microfluidic channel 215. The obstacle 220 may extend to or from a flat bottom surface of the microfluidic channel 215. In some embodiments, the obstacle 220 may extend from multiple surfaces of the microfluidic channel 215, for example, the obstacle may extend to or from a flat bottom surface formed by a first long side and a flat top surface formed by a second long side of the substantially rectangular cross-section.

[0049] In some embodiments, the obstacles 220 may be dimples extending from the microfluidic channel 215, as expressly incorporated by reference herein and as further discussed with respect to the microfluidic device 100. In some embodiments, the obstacles 220 may be protrusions extending into the microfluidic channel 215.

[0050] As further shown, the microfluidic device 200 may be in the form of or included in a microfluidic chip. In some embodiments, the microfluidic chip may be formed by a two-piece housing joined by one or more removable fasteners, such as screws, nuts, bolts, clips, straps, and / or pins. For example, the microfluidic channel 114 may be formed in a component of the two-piece housing, or in both. However, the microfluidic channel 114 may also be formed in a separate microfluidic structure or plate received between the two-piece housing to seal the microfluidic structure therebetween. One or more inlet ports 102, 104 and / or one or more outlet ports 108 (as shown with respect to the microfluidic device 100) may be formed in the housing. In some embodiments, the microfluidic device 200 may be a single, integral part (e.g., formed through injection molding or three-dimensional printing). The adapter 200 may be fabricated or formed similarly to the microfluidic device 100, as expressly incorporated herein by reference.

[0051] The microfluidic channel 215 is configured to mix a first substance with a second substance to form nanoparticles and separate the nanoparticles, and the first inlet channel 210 and the second channel 212 may be directly connected to the microfluidic channel 215, as shown in FIG. 5 . However, in some embodiments, the nanoparticles may be formed by a second channel, such as the microfluidic channel 114, fluidly connected to the microfluidic channel 215. Thus, the system may include a first microfluidic channel having a first cross-section for mixing (as shown with respect to the microfluidic channel 114) and a second microfluidic channel having a second cross-section for separating the formed nanoparticles (as shown with respect to the microfluidic channel 215). The inlet ports 210, 212 may be directly connected to the microfluidic channel 115, or the first microfluidic channel 115 and the second microfluidic channel 215 may be connected by a single connecting channel. For example, the first microfluidic channel 115 may have circumferentially arranged dimples to mix the first and second materials to form nanoparticles, and the second microfluidic channel 215 may have laterally arranged dimples to separate the formed nanoparticles. Microfluidic channel 114 and microfluidic channel 215 may be in the same chip or different chips. In some embodiments, if on different chips, the chips may have different inlets and / or outlets.

[0052] Those skilled in the art will also understand that modifications may be made to the exemplary embodiments described herein without departing from the invention. Structural features of the systems and devices described herein may be replaced with functionally equivalent parts. Furthermore, it will be understood that features from the embodiments may be combined with one another without departing from the disclosure.

Claims

1. at least one inlet channel; a microfluidic channel having a first portion fluidly connected to the at least one inlet channel; at least one outlet channel fluidly connected to a second portion of the microfluidic channel; Including, the microfluidic channel having a plurality of dimples extending away from an axis of the microfluidic channel; Microfluidic devices.

2. The microfluidic device of claim 1 , wherein the at least one inlet channel comprises a first inlet channel and a second inlet channel.

3. The microfluidic device of claim 1 , wherein the at least one outlet channel comprises a first outlet channel and a second outlet channel.

4. The microfluidic device of claim 1 , wherein the plurality of dimples are circumferentially arranged around the microfluidic channel.

5. The microfluidic device of claim 4 , wherein the plurality of dimples are arranged in longitudinally overlapping sets.

6. 2. The microfluidic device of claim 1, wherein the plurality of dimples comprises a first set of dimples arranged longitudinally along the microfluidic channel and a second set of dimples arranged longitudinally along the microfluidic channel, the first set of dimples and the second set of dimples being laterally offset, and the first set of dimples and the second set of dimples being configured to separate nanoparticles by size.

7. 7. The microfluidic device of claim 6, wherein the first set of dimples has a first width or diameter and the second set of dimples has a second width or diameter of a second size, the first width or diameter being different from the second width or diameter.

8. 8. The microfluidic device of claim 7, wherein the first width or diameter is from about 50 μm to about 200 μm and the second width or diameter is from about 200 μm to about 500 μm.

9. 7. The microfluidic device of claim 6, wherein the at least one outlet channel comprises a first outlet channel and a second outlet channel, the first set of dimples being arranged to guide nanoparticles of a first size into the first outlet channel and the second set of dimples being arranged to guide nanoparticles of a second size into the second outlet channel.

10. 10. The microfluidic device of claim 9, wherein the at least one outlet channel comprises a third outlet channel, and the plurality of dimples comprises a third set of dimples arranged longitudinally along the microfluidic channel.

11. The microfluidic device of claim 10 , wherein the third set of dimples is configured to guide nanoparticles of the second size into the third outlet channel.

12. a plurality of inlet channels; a microfluidic channel having a first portion fluidly connected to the plurality of inlet channels; a plurality of outlet channels fluidly connected to a second portion of the microfluidic channel; Including, the microfluidic channel having a plurality of dimples extending away from an axis of the microfluidic channel; Microfluidic devices.

13. The microfluidic device of claim 12 , wherein the plurality of outlet channels comprises a first outlet channel, a second outlet channel, and a third outlet channel.

14. 13. The microfluidic device of claim 12, wherein the plurality of dimples comprises: a first set of dimples positioned to guide nanoparticles of a first size into the first outlet channel; a second set of dimples positioned to guide nanoparticles of a second size into the second outlet channel; and a third set of dimples positioned to guide nanoparticles of the second size into the second outlet channel.

15. 1. A method for fabricating a microfluidic channel, comprising: injecting one or more elastomeric materials into the mold cavity around a core pin, the core pin having an elongated shaft with a plurality of protrusions extending from an axis of the core pin; forming a component including a microfluidic channel with a plurality of dimples from the one or more elastomeric materials; removing the core pin from the component; A method comprising:

16. The method of claim 15 further comprising removing the component and central core from the mold cavity before removing the core pin from the component.

17. The method of claim 15 , wherein the one or more elastomeric materials may include silicone, rubber, and / or a thermoplastic elastomer.

18. The method of claim 15 , wherein removing the core pin from the component is performed using a compressed air ejector system.

19. The method of claim 15 , wherein removing the core pin from the component is accomplished by sliding the component off the core pin.

20. The method of claim 15 , wherein the protrusions are spherical.

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