WO2025151447A1

WO2025151447A1 - Microfluidic devices with inertial focusing

Info

Publication number: WO2025151447A1
Application number: PCT/US2025/010619
Authority: WO
Inventors: Wujun Zhao; Mohammad Karim DEHGHAN MANSHADI; Zheng Xia
Original assignee: ABS Global Inc
Current assignee: ABS Global Inc
Priority date: 2024-01-08
Filing date: 2025-01-07
Publication date: 2025-07-17
Anticipated expiration: 2026-07-08

Abstract

Disclosed herein is a microfluidic chip for positioning samples for particle tracing. In some examples, the microfluidic chip includes a first microchannel and a second microchannel. The first microchannel and the second microchannel are mated to form a junction, with a lateral distance of the first microchannel being less than a lateral distance of the second microchannel.

Description

MICROFLUIDIC DEVICES WITH INERTIAL FOCUSING

TECHNICAL FIELD

[0001] Disclosed are methods, devices, and systems for inertially focusing a fluid stream having a single particle equilibrium position, for example. Microfluidic chips for positioning samples for interrogation are disclosed. The approach can provide, for example and without limitation, systems and methods for analyzing bovine sperm cells to produce embryos with preselected genetic traits.

BACKGROUND

[0002] In the beef production industry, mating is typically done through natural service, whereby male cattle (bulls) are present on a farm and roaming freely with a herd of cows during breeding season. This practice requires minimal intervention but comes with certain notable disadvantages. For example, breeders have very' little control when selecting the traits of the resulting offspring. As a result, there is no guarantee that the desired traits (e g., a specific sex and/or the like) will ultimately be selected. And while artificial insemination techniques exist to assist in increasing the control breeders have over such selection, these techniques have varying success rates.

[0003] In the dairy industry, farmers have historically used conventional semen and have fertilized their herds via artificial insemination. However, with the development of sexed semen technology, farmers are using an increasing proportion of sexed semen in their herds. Specifically, farmers are using sexed semen from high quality' genetics sources (e.g., high Net Merit bulls) to breed their highest genomic value cows to produce replacement animals for their herds. As a result, the demand for high quality sexed semen continues to increase and outpaces producers’ ability to meet that demand.

[0004] Microfluidics chips have recently been developed to enable the manipulation of fluids on microscopic scales, and are being applied to address the above-noted problems in semen selection. Conventional techniques for focusing fluids in a microfluidic chip include shaping the microchannels to focus the fluids. However, these techniques are limited and often result in the fluids focusing within these microfluidic chips at multiple points within a microchannel. This can result in unintentional selection of samples for removal as the fluids flow through the microfluidic chip, and ultimately the waste (e.g., destruction) of otherwise desirable semen.

BRIEF SUMMARY

[0005] In an embodiment, the present disclosure provides a method for producing an inertially focused sample fluid stream having a single particle equilibrium position. In aspects, the method includes: introducing a sheath fluid to a microfluidic chip; introducing a sample fluid to the microfluidic chip; and flowing the sheath fluid and the sample fluid through at least a portion of the microfluidic chip such that particles in the sample fluid are inertially focused based on the sample fluid coming into fluid contact with the sheath fluid.

[0006] In some aspects, introduction of the sample fluid forms a sample fluid stream, and introduction of the sheath fluid forms a sheath fluid stream, and flowing the sheath fluid and the sample fluid through the at least a portion of the microfluidic chip comprises inertially focusing particles in the sample fluid stream based on the sheath fluid stream coming into fluid contact with the sample fluid stream.

[0007] In aspects, introducing the sample fluid into the microfluidic chip comprises introducing the sample fluid into the microfluidic chip via a first inlet corresponding to a first microchannel, and introducing the sheath fluid into the microfluidic chip comprises introducing the sheath fluid into the microfluidic chip via a second inlet corresponding to a second microchannel.

[0008] In some aspects, the method further includes: flowing the sample fluid stream through the first microchannel, where the first microchannel is positioned above the second microchannel, and structured to focus the sample fluid stream; flowing the sheath fluid stream through the second microchannel, where the second microchannel is positioned below the first microchannel, and sized and dimensioned to focus the sheath fluid stream; and flowing the sample fluid stream such that the sample fluid stream comes into fluid contact with the sheath fluid stream along a portion of a third microchannel at a junction, the junction defined by a fluid connection between the first microchannel and the second microchannel.

[0009] According to aspects, the method further includes: flowing the sample fluid stream and the sheath fluid stream through the third microchannel. The third microchannel may be positioned downstream from the first microchannel and the second microchannel, and the third microchannel may be structured to inertially focus particles in the sample fluid stream at a single particle equilibrium position.

[0010] In aspects, flowing the sheath fluid and the sample fluid through the at least a portion of the microfluidic chip includes: flowing the sheath fluid and the sample fluid through at least a portion of the microfluidic chip such that particles in the sample fluid are inertially focused as a result of the sample fluid coming into fluid contact with the sheath fluid.

[0011] In an embodiment, the present disclosure provides a device for producing an inertially focused sample fluid stream having a single particle equilibrium position. In aspects, the device includes a microfluidic chip and the device is configured, in operation, to: receive a sheath fluid into a microfluidic chip; receive a sample fluid into the microfluidic chip; and flow the sheath fluid and the sample fluid through at least a portion of the microfluidic chip such that particles in the sample fluid are inertially focused based on the sample fluid coming into fluid contact with the sheath fluid.

[0012] In aspects, when flowing the sheath fluid and the sample fluid through at least a portion of the microfluidic chip, the device is configured, in operation, to: flow the sheath fluid and the sample fluid through at least a portion of the microfluidic chip such that particles in the sample fluid are inertially focused in response to the sample fluid coming into fluid contact with the sheath fluid.

[0013] In an embodiment, the present disclosure provides a method for producing an inertially focused sample fluid stream having a single particle equilibrium position. In aspects, the method includes: introducing a sheath fluid stream into a microfluidic channel; introducing a sample fluid stream into an upper portion of the microfluidic channel; and flowing the sheath fluid stream and the sample fluid stream through a downstream portion of the microfluidic channel, a structure of the downstream portion of the microfluidic channel being adapted to inertially focus the sample fluid stream and particles disposed in the sample fluid stream. The introduction of the sample fluid stream into the upper portion of the microfluidic channel and the inertial focusing of the sample fluid stream by the structure of the downstream portion of the microfluidic channel may produce an inertially focused sample fluid stream having a single particle equilibrium position. [0014] In an embodiment, the present disclosure provides a device for producing an inertially focused sample fluid stream having a single particle equilibrium position. The device may have a microfluidic channel with an upper portion and a downstream portion, the device being configured, in operation, to: receive a sheath fluid stream into the microfluidic channel; receive a sample fluid stream into the upper portion of the microfluidic channel; and flow the sheath fluid stream and the sample fluid stream through the downstream portion of the microfluidic channel, the downstream portion of the microfluidic channel having a structure adapted to inertially focus the sample fluid stream and particles disposed in the sample fluid stream. The inertial focusing of the sample fluid stream by the structure of the downstream portion of the microfluidic channel may produces an inertially focused sample fluid stream having a single particle equilibrium position.

[0015] In an embodiment, the present disclosure provides a microfluidic chip for producing an inertially focused sample fluid stream having a single particle equilibrium position, the microfluidic chip comprising: a first microchannel for regulating fluid flow between an upstream portion of the first microchannel and a downstream portion of the first microchannel, the first microchannel in fluid communication with a first inlet positioned along the upstream portion of the first microchannel; a second microchannel for regulating fluid flow betw een an upstream portion of the second microchannel and a downstream portion of the second microchannel, the second microchannel in fluid communication with a second inlet positioned along the upstream portion of the second microchannel, wherein an opening in the downstream portion of the first microchannel is mated with an opening in the downstream portion of the second microchannel to form a junction, and wherein, a lateral distance of the first microchannel that is associated with the junction is greater than a lateral distance of the second microchannel that is associated with the junction.

[0016] In an aspect, the junction comprises a taper along a downstream portion of the junction. According to aspects, the downstream portion of the first microchannel is aligned with the downstream portion of the second microchannel along a common axis. At the junction, the first microchannel and the second microchannel may extend along the common axis for a distance, the distance being a distance between 200-300 pm.

[0017] In aspects, the downstream portion of the first microchannel is aligned with the downstream portion of the second microchannel along parallel axes. In some aspects, the microfluidic chip further includes a third microchannel in fluid communication with the first microchannel and the second microchannel at the junction. The third microchannel may include an upstream portion and a downstream portion, and the upstream portion of the third microchannel may include a curved structure. The curved structure may include a spiral structure. The spiral structure may form an Archimedes spiral. The spiral may include a number of rotations, the number of rotations being between one rotation and three rotations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 A is a top view of a microfluidic chip, according to non-limiting embodiments of the present disclosure.

[0019] FIG. IB is a perspective view' of a portion of the microfluidic chip of FIG. 1A.

[0020] FIG. 1C is a top view' of a portion of the microfluidic chip of FIG. 1 A.

[0021] FIG. ID is a side view of a portion of the microfluidic chip of FIG. 1A.

[0022] FIGS. 1E-1H are illustrations of the flow' of fluid passing through portions of the microfluidic chip of FIG. 1A.

[0023] FIG. 2A is a top view of a microfluidic chip, according to non-limiting embodiments of the present disclosure.

[0024] FIG. 2B is a side view of the microfluidic chip of FIG. 2A.

[0025] FIG. 2C is a perspective view of the microfluidic chip of FIG. 2A.

[0026] FIG. 2D is another top view of the microfluidic chip of FIG. 2A.

[0027] FIG. 2E is a section view' of a portion of the microfluidic chip of FIG. 2A.

[0028] FIG. 2F is a perspective view' of a portion of the microfluidic chip of FIG. 2A.

[0029] FIG. 2G is another top view of the microfluidic chip of FIG. 2A.

[0030] FIG. 2H is another top view of the microfluidic chip of FIG. 2A w ith certain hidden lines visible. [0031] FIG. 2I-2L are illustrations of the flow of fluid passing through portions of the microfluidic chip of FIG. 2A.

[0032] FIG. 2M is a diagram of particle shear rates changing over time as fluid passes through portions of the microfluidic chip of FIG. 2A.

[0033] FIG. 3 is a block diagram of a microfluidics system that includes a computing device and a sample processing system, according to non-limiting embodiments of the present disclosure.

[0034] FIG. 4 is a flow diagram of an example process for producing an inertially focused sample fluid stream having a single particle equilibrium position, according to nonlimiting embodiments of the present disclosure.

DETAILED DESCRIPTION

[0035] Embodiments of the present disclosure are described with reference to the drawings. Like numerals may designate identical or corresponding elements in each of the several views.

[0036] Throughout this description, the term “upstream” will refer to portions of the device or component thereof that are closer to portions of the device configured to receive fluids therein (such as inlets and/or microwells), and the term “downstream” will refer to portions of the device or component that are farther from portions of the device that are configured to receive the fluids therein.

[0037] In the drawings and the description that follows, terms such as front, rear, upper, lower, top, bottom, and similar directional terms are used simply for convenience of description and are not intended to limit the disclosure unless expressly stated otherwise. Well-known functions and/or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

[0038] Described herein are systems and methods for producing an inertially focused sample fluid stream having a single particle equilibrium position. For example, methods described herein involve introducing a sheath fluid to a microfluidic chip; introducing a sample fluid to the microfluidic chip; and flowing the sheath fluid and the sample fluid through at least a portion of the microfluidic chip such that particles in the sample fluid are inertially focused based on the sample fluid coming into fluid contact with the sheath fluid.

[0039] By virtue of the implementation of the systems and methods described herein, dairy production can be improved. More specifically, semen from bulls (e.g.. the top 20-50% of the most genetically desirable bulls) can be selected by flowing the semen through the microfluidic chips descnbed herein via a sample fluid stream. As the semen is flowed through the microfluidic chip, it can be focused. This focusing allows for improved interrogation at predetermined points within the microfluidic chip. Once inseminated, the resulting cows may be used to replace the existing herd, thereby continually improving the herd’s overall milk production.

[0040] Referring now to FIG. 1A, illustrated is an embodiment of a microfluidic chip 100 provided in accordance with the present disclosure. The microfluidic chip 100 comprises an upstream portion 100a and a downstream portion 100b. The microfluidic chip 100 is substantially planar and comprises an exterior which is defined by a top surface 102, a perimeter 104, and a bottom surface 106. Although generally illustrated as comprising a rectangular profile, the microfluidic chip 100 may be formed in any suitable profile capable of receiving, processing, and discharging fluids as described herein. Examples of other suitable profiles include square profiles and/or the like.

[0041] In some embodiments, the microfluidic chip 100 is comprised of one or more materials. For example, the microfluidic chip 100 may be comprised of one or more of polydimethylsiloxane (PDMS), thermoplastics, glass, silicon, metals, and composites. As described below, the microfluidic chip 100 includes one or more structures therein. The microfluidic chip 100 may be manufactured using one or more manufacturing techniques. These techniques can include photolithography, soft lithography, hot embossing, micro machining, injection molding, and/or 3D printing.

[0042] The upstream portion 100a of the micro fluidic chip 100 comprises a sample inlet 108 configured to receive a sample fluid therein. The sample inlet 108 (sometimes referred to as a microwell) comprises a first opening 108a which is configured to receive a first fluid therein. The sample inlet 108 may be configured to receive the first fluid at a pressure from among a first range of pressures. The first opening 108a defines a substantially circular opening. In embodiments, the opening may be defined as any suitable shape. The first inlet 108 is fluidly coupled to a first microchannel 112.

[0043] The first microchannel 112 comprises an upstream portion 116a and a downstream portion 116b. The upstream portion 116a and the downstream portion 116b of the first microchannel 112 are sized and dimensioned to flow fluid therebetween along a first plane. The first plane is substantially coplanar with a plan defined by the microfluidic chip 100. As best shown in FIG. 1A, the upstream portion 116a and the downstream portion 116b join to form an elbow. In embodiments, the upstream portion 116a and downstream portion 116b may join to form any suitable shape or may be substantially straight.

[0044] The upstream portion 100a of the microfluidic chip 100 also comprises a sheath inlet 110 configured to receive a sheath fluid therein. The sheath inlet 110 (sometimes referred to as a microwell) comprises a first opening 110a which is configured to receive a second fluid therein. The sheath inlet 110 may be configured to receive the second fluid at a pressure from among a second range of pressures which may overlap and/or be distinct from the first range of pressures. The second opening 110a defines a substantially circular opening. In embodiments, the opening may be defined as any suitable shape. The second inlet 110 is fluidly coupled to a second microchannel 114.

[0045] The second microchannel 114 comprises an upstream portion 118a and a downstream portion 118b. The upstream portion 118a and the downstream portion 118b are sized and dimensioned to flow fluid therebetween along a second plane. As best shown in FIG. 1A, the upstream portion 118a and the downstream portion 118b join to form an elbow. In embodiments, the upstream portion 118a and downstream portion 118b may join to form any suitable shape or may be substantially straight.

[0046] The microfluidic chip 100 comprises an intersecting region 120, where the first microchannel 112 and the second microchannel 114 intersect. More specifically, at the intersecting region 120, the downstream portion 116b of the first microchannel 112 fluidly connects with the downstream portion 118b of the second microchannel 114 at a junction 122 to enable fluid flow from the first microchannel 112 and second microchannel 114 to a third microchannel 124. While described separately for ease of description, it will be understood that the second microchannel 114 and the third microchannel 124 may be joined to form one continuous microchannel. [0047] The third microchannel 124 is configured to receive fluid from the downstream portion 116b of the first microchannel and the downstream portion of 118b of the second microchannel 114 starting at the junction 122. As illustrated, the third microchannel 124 may be sized and dimensioned to match the size and dimension of the second microchannel 114 where the second microchannel 114 meets the third microchannel 124. As illustrated, the second microchannel 114 and the third microchannel 124 meet at the junction 122. It will be understood that, in embodiments, the second microchannel 114 and the third microchannel 124 may meet in a variety of positions relative to the junction 122.

[0048] The third microchannel 124 extends downstream from the j unction 122. As the third microchannel 124 extends downstream, the third microchannel 124 can taper from a first width (e.g., a width (e.g., between 10-700 pm) to a second width (e.g., between 1-100 pm). As illustrated, as the third microchannel 124 begins to taper while extending dow nstream, the third microchannel 124 forms a spiral 126. The taper extends from a first portion of the spiral 126 (e.g., a beginning of the spiral 126) to a second portion of the spiral 126 (e.g., to a point where the radius initially extends from an origin of the spiral and the radius extending from the origin to a point where the taper ends form an angle 0). As illustrated, the angle 0 is 90 degrees with a constant taper (e.g., a taper having a constant or uniform decrease in size). In embodiments, the angle 0 may be any other suitable angle.

[0049] As illustrated, the spiral 126 extends such that 0 = 630 degrees, thereby enabling fluid flow' to progresses linearly across the microfluidic chip 110 along an axis (referred to as the longitudinal axis of the microfluidic chip 100 and represented by axis identifier A-A in FIG. 1 A) defined by the progression of the microfluidic chip 100 betw een the upstream portion 110a of the microfluidic chip 100 and the downstream portion 100b of the microfluidic chip 100. It will be understood that 0 may extend any suitable number of degrees (e.g., between 1 degree and 1440 degrees) and that in some embodiments, the fluid flow through the microfluidic chip 100 may not progress linearly (e.g., fluid may flow toward the sides (located at the top and bottom of FIG. 1A) of the microfluidic chip 100. As illustrated, the spiral 126 is an Archimedean spiral. The width of the spiral 126 along points of the spiral 126 may be between 50 pm and 250 pm and the height of the spiral 126 may be between 40 pm and 50 pm.

[0050] The third microchannel 124 further comprises an expanding region 128. The expanding region 128 extends between a first expansion point 130 and a second expansion point 132. The width of the third microchannel 124 at the first expansion point 130 comprises a first width (e.g., between 1 pm and 125 pm); and the width of the third microchannel 124 at the second expansion point 132 comprises a second width (e.g., between 10 pm and 700 pm). The third microchannel 124 extends from the second expansion point 132 across the dow nstream portion 100b of the microfluidic chip 100. As illustrated, the third microchannel 124 forms an outlet 134 at the perimeter of the microfluidic chip 100 to eject fluid as it flows through the third microchannel 124. It will be understood that the third microchannel 124 may form an outlet at any point along the perimeter of the microfluidic chip 100.

[0051] In some embodiments, the microfluidic chip 100 includes a channel 136. In some embodiments, the channel is hollow. In other embodiments, the channel comprises a material that permits the passage of light to be transmitted to the fluids passing through the third microchannel 124.

[0052] Referring now to FIG. IB, and with continued reference to the microfluidic chip 100 of FIGs. 1 A and IB, illustrated is an perspective view of a portion of the microfluidic chip 100. As illustrated, the upstream portion 116a of the first microchannel 112 is positioned above the first upstream portion 118a of the second microchannel 114. The first upstream portion 116a connects to the first downstream portion 116b, with both the upstream portion 116a and downstream portion 116b of the first microchannel 112 comprising a rectangular profile. In some embodiments, the first microchannel 112, the second microchannel 1 14, and/or the third microchannel 124 may comprise any suitable profile, such as circular profiles, elliptical profiles, cylindrical profiles, and/or the like.

[0053] Continuing from the point at which the upstream portion 11 a and the downstream portion 116b of the first microchannel 112 connect, the dow nstream portion 116b of the first microchannel 112 comprises a taper along lateral axis (represented by axis identifier B-B in FIG. IB) between a first width (e.g., between 10 pm and 700 pm) and a second width (e.g., between 1 pm and 125 pm). The taper extends along the dow nstream portion 1 16b of the first microchannel 112 until the first microchannel 112 meets the second microchannel 114 at the junction 122. Again, with reference to the point at which the upstream portion 116a and the downstream portion 116 of the first microchannel 112 connect, the downstream portion 116b of the first microchannel 112 comprises a taper along a vertical axis (represented by axis identifier C-C in FIG. IB) between a first width (e.g., betw een 10 pm and 700 pm) and a second width (e.g.. between 1 pm and 100 pm). The taper extends along the downstream portion 116b of the first microchannel 112 until the first microchannel 112 meets the second microchannel 114 at the junction 122.

[0054] As shown in FIG. IB, the downstream portion 116b of the first microchannel 112 comprises a descending portion 116c. The descending portion 116c of the first microchannel 112 continues from a first height downward toward a second height relative to (e.g., internal to) the microfluidic chip 100 to enable a fluid connection between the first microchannel 112 and the second microchannel 114 at the junction 122.

[0055] The downstream portion 118b of the second microchannel 114 comprises an ascending portion 118c. Converse to the descending portion 116 of the first microchannel 112, the ascending portion 118c of the second microchannel 114 continues from a first height upward toward a second height relative to the microfluidic chip 100. The ascending portion 118c then levels and the downstream portion 118b of the second microchannel 114 continues until meeting with the dow nstream portion 116b of the first microchannel 112. The ascending portion 118c also comprises a taper defined by a progressive narrowing of a top surface and a bottom surface of the ascending portion 118c. In this way, the level portion of the downstream portion 118b of the second microchannel 114 narrows in its vertical profile such that the vertical profile of the second microchannel 114 matches a vertical profile of the third microchannel 124.

[0056] The first microchannel 112 and the second microchannel 114 join at the junction 122. more specifically, at thejunction, the first microchannel 112 has a lateral width that is less than the lateral width of the second microchannel 114 at thejunction 122, and an opening along the downstream portion 116b of the first microchannel 112 mates with an opening along the downstream portion of the second microchannel 114 (not explicitly shown) to enable fluid communication therethrough. The opening of the downstream portion 116b of the first microchannel may be sized and dimensioned to enable fluid to flow therethrough. More specifically, the opening of the downstream portion 116b of the first microchannel may be sized and dimensioned such that fluid flows outward from the opening at an angle between - 10 and -45 degrees relative to the axis A- A, while fluid continues to flow through the downstream portion 118b of the second microchannel 1 14 in parallel with the axis A-A. [0057] Referring now to FIG. 1C, illustrated is a top view of a portion of the microfluidic chip 100 of FIG. 1A. As illustrated, the lateral width of the downstream portion 118b of the second microchannel is 650 pm. Further, the later width of the downstream portion 116b of the first microchannel 112 is also 650 pm. The downstream portion 116b of the first microchannel 112 tapers to a lateral width of 100 pm.

[0058] Referring now to FIG. ID, illustrated is a side view of a portion of the microfluidic chip 100 of FIG. 1 A. As illustrated, the junction extends from a point at which the downward taper of the downstream portion 116b of the first microchannel 112 levels for a distance of 242 pm. Prior to leveling, a bottom surface of the downstream portion 116b of the first microchannel 112 forms a 13 degree angle with a top surface of the downstream portion 118b of the second microchannel 114. The downstream-most portion of the then again tapers downward at 45 degrees until connecting with the downstream portion 118b of the second microchannel 114. The height of the downstream portion 116b of the first microchannel 112 along the junction 112 is 50 pm.

[0059] With continued reference to FIG. ID, as discussed above, the downstream portion 118b of the second microchannel 114 comprises an ascending portion 118c in which the second fluid (e.g., sheath fluid) flows upward before finally leveling off within the downstream portion 118b of the second microchannel 114. Similarly, the descending portion 1 16 of the first microchannel 112 descends such that the first fluid (e.g., sample fluid) flow s downward before finally leveling off within the downstream portion 116b of the first microchannel 112. A distance between the point at which the ascending portion 118c of the second microchannel 114 levels extends a distance of 350 pm along the longitudinal axis A-A until meeting the point at which the descending portion 116c of the first microchannel 112 levels.

[0060] Referring now to FIGS. 1E-1G, illustrated is the flow of fluid passing through portions of the microfluidic chip 100 of FIG. 1A. As illustrated, a first fluid (e.g., a sample fluid) is introduced to the first microchannel 1 12. The first fluid then flows downstream from an upstream portion 116a of the first microchannel through to a downstream portion 116b of the first microchannel 112. The first fluid then comes into fluid contact with the second fluid (e.g., a sheath fluid) where the first microchannel 112 fluidly couples to the second microchannel 114. [0061] Similarly, the second fluid is introduced to the second microchannel 114. The second fluid then flows downstream from an upstream portion 118a of the second microchannel 114 through to a downstream portion 118b of the second microchannel 1 14. The second fluid then comes into contact with the first fluid at the junction 122.

[0062] As the fluids join in the junction, they continue flowing through the third microchannel 124. By virtue of the inertial forces exerted by the second fluid on the first fluid, the first fluid (e.g., a stream formed by the first fluid) is focused relative to the second fluid (e.g., a stream formed by the second fluid) in the third microchannel 124. More specifically, as the first fluid and the second fluid flow through a focused region 138 of the spiral 126 (see FIGS. 1G and 1H). a stream associated with the first fluid is focused within the spiral 126 based on the stream associated with the first fluid moving in a first direction (e.g., clockwise or counterclockwise within the spiral 126) and the stream associate with the second fluid flowing moving in a second direction counter to the first direction (e.g., the opposite of the clockwise or counterclockwise direction associated with the first direction) within the spiral 126. In some embodiments, the focused region 138 may be the same as, or similar to, the point at which the spiral 126 of the third microchannel 124 straightens. As illustrated by FIGs. 1G and 1H, in the focused region 138 is focused at a point within the third microchannel 124. In various embodiments, while flowing through the focused region 138, the sample flow rate may be 0.001 mL/min to 0.04 mL/min (e.g.. approximately 0.02 ml/min in an example embodiment), the sheath flow rate may be 0.5 mL/min to 2 mL/min (e.g., approximately 1. 136 ml/min in an example embodiment), the pressure of the sample fluid may be 50 psi to 100 psi (e.g., 99.55 psi in an example embodiment), the pressure of the sheath fluid may be 50 psi to 100 psi (e.g., 100 psi in an example embodiment), the maximum velocity of the sample fluid and/or the sheath fluid may be approximately 7 m/s to 7.5 m/s (e.g., 7.20 m/s in an example embodiment), a Y-width (illustrated as measured by FIG. 1H) may be approximately +8 pm to +12 pm (e.g., +10 pm in an example embodiment), aZ-offset may be approximately +18 pm to +22 pm (e.g., +19.3 pm in an example embodiment), and an average particle velocity of the particles flowing in the sample fluid stream may be approximately 5 m/s to 7 m/s (e.g., 5.9 m/s in an example embodiment).

[0063] In some embodiments, an interrogation laser and an ablation laser (not explicitly illustrated) may be focused at one or more points along the microfluidic chip 100. For example, the interrogation laser (e.g., a laser that emits energy which is collected by a photodetector for analysis) may be positioned above the microfluidic chip 100 and focused along a point along the microfluidic chip 100. The ablation laser may be focused at a point along the microfluidic chip 100 that is downstream from the point at which the interrogation laser is focused and activated based on signals generated by the interrogation laser. The interrogation laser and the ablation laser may be positioned such that the energy emitted by both lasers is transmitted along a plane that is substantially transverse to the plane defined by the microfluidic chip 100.

[0064] Referring now to FIGS. 2A-2C, illustrated is an embodiment of a microfluidic chip 200 provided in accordance with the present disclosure. The microfluidic chip 200 comprises an upstream portion 200a and a downstream portion 200b. The microfluidic chip 200 is substantially planar and comprises an exterior which is defined by a top surface 202, a perimeter 204, and a bottom surface 206. Although generally illustrated as comprising a rectangular profile, the microfluidic chip 200 may be formed in any suitable profile capable of receiving, processing, and discharging fluids as described herein. Examples of other suitable profiles include square profiles and/or the like. It will be understood that certain aspects of the microfluidic chip 200 may be the same as, or similar to, aspects of the microfluidic chip 100 as illustrated in FIGS. 1A-1D, and that like numerals may correspond to the same, or similar, structural features.

[0065] In some embodiments, the microfluidic chip 200 is comprised of one or more materials. For example, the microfluidic chip 200 may be comprised of one or more of polydimethylsiloxane (PDMS), thermoplastics, glass, silicon, metals, and composites. As described below, the microfluidic chip 200 includes one or more structures therein. The microfluidic chip 200 may be manufactured using one or more manufacturing techniques. These techniques can include photolithography, soft lithography, hot embossing, micro machining, injection molding, and/or 3D printing.

[0066] The upstream portion 200a of the microfluidic chip 200 comprises a sample inlet 208 configured to receive a sample fluid therein. The sample inlet 208 (sometimes referred to as a microwell) comprises a first opening 208a which is configured to receive a first fluid therein. The sample inlet 208 may be configured to receive the first fluid at a pressure from among a first range of pressures. The first opening 208a defines a substantially circular opening. In embodiments, the opening may be defined as any suitable shape. The first inlet 208 is fluidly coupled to a first microchannel 212. [0067] The first microchannel 212 comprises an upstream portion 216a and a downstream portion 216b. The upstream portion 216a and the downstream portion 216b of the first microchannel 212 are sized and dimensioned to flow fluid therebetween along a first plane. The first plane is substantially coplanar with a plane defined by the microfluidic chip 200. While illustrated as being substantially linear, in embodiments the upstream portion 216a and downstream portion 216b may join to form any suitable shape or may be substantially straight. As best illustrated in FIG. 2B, the downstream portion 216b of the first microchannel 212 comprises a taper that causes a vertical height of the first microchannel 212 to narrow- before the first microchannel 212 fluidly connects to a sheath inlet 210.

[0068] The upstream portion 200a of the microfluidic chip 200 also comprises a sheath inlet 210 configured to receive a sheath fluid therein. The sheath inlet 210 (sometimes referred to as a microwell) comprises a first opening 210a which is configured to receive a second fluid therein. The sheath inlet 210 may be configured to receive the second fluid at a pressure from among a second range of pressures which may overlap and/or be distinct from the first range of pressures. In one embodiment, the first and second ranges of pressures are instead measured as first and second ranges of fluid flow rates as controlled by a flow controller. The second opening 210a defines a substantially circular opening. In embodiments, the opening may be defined as any suitable shape. The second inlet 210 is fluidly coupled to the first microchannel 212. More specifically, the second inlet includes a second opening 210b which mates to fluidly connect with the first microchannel 212. As shown in FIG. 2B, the second opening 210a is between a top portion and a bottom portion of the sheath inlet 210. In embodiments, the second opening may be positioned at any vertical location along the sheath inlet 210.

[0069] The sheath inlet 210 extends downward relative to the microfluidic chip 200 and mates with a second microchannel 224 to fluidly connect with the second microchannel 224. The second microchannel 224 of the microfluidic chip 200 configured to receive fluid from the downstream portion 216b of the first microchannel and a lower portion of the sheath inlet 210. As illustrated, the second microchannel 224 may be sized and dimensioned to match the size and dimension of the lower portion of the sheath inlet 210.

[0070] The second microchannel 224 extends downstream from the lower portion of the sheath inlet 210. As the second microchannel 224 extends downstream, the second microchannel 224 can taper from a first width (e.g., a width (e.g., between 10-700 pm) to a second width (e.g., between 1-100 gm). As illustrated, as the second microchannel 224 begins to taper while extending downstream, the second microchannel 224 forms a spiral 226. The taper extends from a first portion of the spiral 226 (e.g., a beginning of the spiral 226) to a second portion of the spiral 226 (e.g., to a point where the radius initially extends from an origin of the spiral and the radius extending from the origin to a point where the taper ends form an angle 0). As illustrated, the angle 0 is 90 degrees with a constant taper (e.g., a taper having a constant or uniform decrease in size). In embodiments, the angle 0 may be any other suitable angle.

[0071] As illustrated, the spiral 226 extends such that 0 = 630 degrees, thereby enabling fluid flow to progresses linearly across the microfluidic chip 200 along an axis (referred to as the longitudinal axis of the microfluidic chip 200 and represented by axis identifier A-A in FIG. 1 A) defined by the progression of the microfluidic chip 200 between the upstream portion 200a of the microfluidic chip 200 and the downstream portion 200b of the microfluidic chip 200. It will be understood that 0 may extend any suitable number of degrees (e.g.. between 1 degree and 1440 degrees) and that in some embodiments, the fluid flow through the microfluidic chip 200 may not progress linearly (e.g., fluid may flow toward the sides (located at the top and bottom of FIG. 2A) of the microfluidic chip 200. As illustrated, the spiral 226 is an Archimedean spiral. The width of the spiral 226 along points of the spiral 226 may be between 50-250 pm and the height of the spiral 226 may be between 40 and 50 pm.

[0072] The second microchannel 224 further comprises an expanding region 228. The expanding region 228 extends between a first expansion point 230 and a second expansion point 232. The width of the second microchannel 224 at the first expansion point 230 comprises a first width (e.g., between 1-125 pm); and the width of the second microchannel 224 at the second expansion point 232 comprises a second width (e.g., between 10-700 pm). As best illustrated in FIG. 2E, between the first expansion point 230 and the second expansion point 232 the second microchannel 224 expands vertically relative to the microfluidic chip 200. More specifically, between the first expansion point 230 and the second expansion point 232 the second microchannel 224 expands downward. The second microchannel 224 extends from the second expansion point 232 across the downstream portion 200b of the microfluidic chip 200. As illustrated, the second microchannel 224 forms an outlet 234 at the perimeter of the microfluidic chip 200 to eject fluid as it flows through the second microchannel 224. It will be understood that the third microchannel 224 may form an outlet at any point along the perimeter of the microfluidic chip 200. The expanding region 228 is generally positioned downstream or after an interrogation region of the microfluidic chip 200. The purpose of the expanding region 228 is to provide a pressure drop to reduce the overall fluidic pressure in the microfluidic chip 200. This positioning of the expanding region and role in providing a pressure drop to reduce overall fluidic pressure is also applicable to other embodiments disclosed herein.

[0073] In some embodiments, the microfluidic chip 200 includes a channel 236. In some embodiments, the channel is hollow. In other embodiments, the channel comprises a material that permits the passage of light to be transmitted to the fluids passing through the second microchannel 224. As best illustrated in FIG. 2D, the microfluidic chip 200 may have material disposed between the channel 236 and the second microchannel 224. In some embodiments, an interrogation laser and an ablation laser (not explicitly illustrated) may be focused at one or more points along the microfluidic chip 200. For example, the interrogation laser (e.g., a laser that emits energy which is collected by a photodetector for analysis) may be positioned above the microfluidic chip 200 and focused along a point along the microfluidic chip 200. The ablation laser may be focused at a point along the microfluidic chip 200 that is downstream from the point at which the interrogation laser is focused and activated based on signals generated by the interrogation laser. The interrogation laser and the ablation laser may be positioned such that the energy emitted by both lasers is transmitted along a plane that is substantially transverse to the plane defined by the microfluidic chip 200.

[0074] Referring now to FIG. 2F, illustrated is a perspective view of a portion of the microfluidic chip 200 of FIG. 2A. More specifically, the perspective view illustrates a cutaway along a horizontal plane of the microfluidic chip 200, with a cut line through a downstream portion 200b of the microfluidic chip 200. As illustrated, the lower portion of the sheath inlet 210 is mated to enable fluid communication between the sheath inlet 210 and an upstream portion of the second microchannel 224. Continuing downstream from the point at which the sheath inlet 210 mates with the second microchannel 224. the second microchannel 224 forms a spiral 226. The spiral 226 may be the same as, or similar to, the spiral 126 of the microfluidic chip 100, as illustrated by FIGS. 1A-1C.

[0075] Referring now to FIGS. 2G and 2H, illustrated is top view of the microfluidic chip 200 of FIG. 2A. As illustrated, the top surface 202 includes a first opening 208a and a second opening 210a. The first opening 208a is configured to receive a first fluid therein (e.g., a sample fluid) and the second opening 210a is configured to receive a second fluid therein (e.g., a sheath fluid). As shown in FIG. 2H. the first microchannel 212 extends from the first opening 208a to the second opening 210a. In this way, a first fluid stream (e.g., a sample fluid stream) is enabled to flow downstream through the microfluidic chip 200 via the first microchannel 212.

[0076] Referring now to FIGS. 2I-2L, illustrated is the flow of fluid passing through portions of the microfluidic chip 200 of FIG. 2A. As illustrated, the first fluid and the second fluid flow through the second microchannel 224 and enters the spiral 226 formed by the second microchannel 224. As the first fluid and the second fluid flow through the spiral 226, a stream formed by the first fluid flows at an initial velocity of approx. 5 m/s, and a stream formed by the second fluid flows at an initial velocity of approx. 1-3 m/s. As both fluids flow through the spiral 226 traveling at approximately 5.5-7 5 m/s while passing through a focused region 238. As illustrated the, the focused region 238 includes a portion of the second microchannel 224 located after termination of the spiral 226. In some embodiments, the focused region 238 may be the same as. or similar to, a detection region. As illustrated in FIG. 21, in the focused region 238 is focused at a point within the second microchannel 124. While flowing through the focused region 238, the Y-width may be 7.4 pm, the Z-offset may be +19.9 pm, the lateral migration may be 24.5 pm, a maximum velocity may be 7.6m/s. a cell velocity⁷ may be 6.5m/s, a flow rate may be 1.247 mL/min., a maximum shear rate may be 8.4xlO^A5, an average sheer rate may be 2.8xlO^A5, and a pressure may be 100 psi.

[0077] Referring now to FIG. 2M, illustrated is a diagram of particle shear rates changing over time as fluid passes through portions of the microfluidic chip 200 of FIG. 2A. As illustrated, at time T=0.000 the shear rate of the particle fluid may be between 0.1xl0^A5 - 6.1xl0^A5 1/s. The shear rate may increase and/or decrease as illustrated to a maximum of 8.5xl0^A5 1/s and a minimum of 0 1/s. As shown, over a period of approximately 0.0045 seconds, the shear rate stabilizes to approximately 1.25 xl0^A5 - 1.75xlO^A5 IF/s.

[0078] Referring now to FIG. 3, illustrated is a block diagram of a microfluidics system 300 that includes a computing device 310 and a sample processing system 350. In some embodiments, the microfluidics system 300 may include the computing device 310 (or multiple computing devices, co-located or remote to each other) and the sample processing system 350. In various embodiments, computing device 310 (or components thereof) may be integrated with the sample processing system 350 (or components thereof). The sample processing system 350 may include a sample platform 354. which may receive a microfluidics chip 358 that receives a sample through a sample channel. The delivery and movement of samples may be controlled by actuators 362 that include fluidics components 366 that control fluid flow or reposition optical components. Optical components 370 may include optical fibers 372, beam splitters 374, or other components (e.g., optical filters, mirrors, and lenses) for receiving, separating, combining, delivering, transmitting, focusing, defocusing, collimating, or guiding light emissions. As used herein, “guiding"’ may include focusing, defocusing, and/or collimating operations with respect to various beams of light. Emissions sources 378 may include various sources of light at different wavelengths and power levels, such as illuminating lights 382 (e.g., an excitation laser) and deactivating and/or activating lights 386 (e.g, a “kill” laser). Sample processing system 350 includes sensors 390, such as a set of light detectors 394 situated at various positions. Sensors 390 may detect light scatter (e.g, light that hits a sample and is scattered in various directions) and fluorescence light (e.g, light emitted, upon excitation by one of the emissions sources 378, by fluorophores in cells or other particles in samples).

[0079] The computing device 310 (or multiple computing devices) may be used to control, and receive signals acquired via, components of sample processing system 350 (e.g., light detected using light detectors 394). The computing device 310 may include one or more processors and one or more volatile and non-volatile memories for storing computing code and data that are captured, acquired, recorded, and/or generated. The computing device 310 may include a control unit 314 that is configured to exchange control signals with sample platform 354, actuators 362, optical components 370, emission sources 378, and/or sensors 390, allowing the computing device 310 to be used to control, for example, delivery' of samples, illumination with light, detection and performance of biasing operations. An analysis module 318 may be used to perform computations on and analyses of data captured using sample processing system 350, and may include, for example, a histogram unit 322 that may generate and process histograms. A biasing module 326 may identify and perform operations based on light detected using sensors 390. such as by controlling actuators 362 (to, e.g, perform gating operations that affect sample flow or reorient light sources to affect aim of the light emitted by the light sources) and/or emission sources 378 (to, e.g., emit light that activates or deactivates particles).

[0080] A transceiver 330 allows the computing device 310 to exchange readings, control commands, and/or other data with sample processing system 350 (or components thereof). One or more user interfaces 334 allow the computing device 310 to receive user inputs (e.g., via a keyboard, touchscreen, microphone, camera, etc.) and provide outputs (e.g.. via display screen, audio speakers, etc.). The computing device 310 may additionally include one or more databases 338 for storing, for example, signals acquired via one or more sensors 390, histograms generated, etc. In some implementations, database 338 (or portions thereof) may alternatively or additionally be part of another computing device that is co-located or remote and in communication with computing device 310 and/or sample processing system 350 (or components thereof).

[0081] Referring now to FIG. 4, an example process 400 for producing an inertially focused sample fluid stream having a single particle equilibrium position. While aspects of the example process 400 will be described with respect to certain structures of the microfluidic chip 100 of FIG. 1 , it will be understood that the process described herein is not limited thereto, and that the process 400 may be implemented using other suitable microfluidic chips.

[0082] At step 402, a sheath fluid is introduced to a microfluidic chip (e.g., a microfluidic chip 100). The sheath fluid may be introduced to the microfluidic chip 100 via a sheath inlet 110 that is associated with a second microchannel 114. In some embodiments, the introduction of the fluid forms a sheath fluid stream. The sheath fluid stream may flow through a portion of the microfluidic chip 100. For example, the sheath fluid stream may flow from the sheath inlet 110 through the second microchannel 114 and eventually through the third microfluidic channel 124. In some embodiments, the sheath fluid stream may flow through portions of the microfluidic chip fOO that are sized and dimensioned to focus the sheath fluid stream as it passes therethrough.

[0083] In some embodiments, the sheath fluid is introduced to the microfluidic chip at a point in time that is earlier than a point in time associated with the introduction of the sample fluid (described below). In this way, a sheath fluid stream may be formed (e.g., established) prior to the formation of a sample fluid stream within the microfluidic chip 100.

[0084] In some embodiments, the sheath fluid is introduced and/or flows through at least a portion of the microfluidic chip 100 that is lower than (e.g.. positioned below) a portion of the microfluidic chip 100 which the sample fluid flows through. [0085] At step 404, a sample fluid is introduced to the microfluidic chip 100. For example, a sample fluid is introduced to a microfluidic chip (e.g., a microfluidic chip 100). The sample fluid may be introduced to the microfluidic chip 100 via a sample inlet 108 that is associated with a first microchannel 112. In some embodiments, the introduction of the sample fluid forms a sample fluid stream. The sample fluid stream may flow⁷ through a portion of the microfluidic chip 100. For example, the sample fluid stream may flow from the sample inlet 108 through the first microchannel 112 and eventually through the third microfluidic channel 124. In some embodiments, the sample fluid stream may flow- through portions of the microfluidic chip 100 that are sized and dimensioned to focus the sample fluid stream as it passes therethrough.

[0086] In some embodiments, the sample fluid is introduced to the microfluidic chip at a point in time that is later than a point in time associated with the introduction of the sheath fluid. In this way, a sample fluid stream may be formed (e.g., established) after the formation of a sheath fluid stream within the microfluidic chip 100. This may reduce waste as the sheath and sample fluids flow through the microfluidic chip 100 to establish the single particle equilibrium position. This also ensures a constant point or area along the microfluidic chip 100 where particles in a sample stream can be reliably detected. In cases where the sample stream is focused using other inertial-based methods, multiple focus points may form along an axis (e.g., a vertical axis) defined by the microfluidic chip, thereby making it difficult for a detection laser beam to be generated and imaged without confusing the particles in, for example, an upper and a lower sample stream. In these cases, the detection laser beam may be focused on the particles flowing through the upper sample stream, the low er sample stream, or both sample streams (e.g.. by focusing on a point between the sample streams), often with low er resolution than could be achieved when focusing on a single stream.

[0087] Further, by implementing the systems and methods described herein, the sample streams described herein can be diluted before interrogation. This, in turn, results in an appropriate amount of particles being present in the stream upon interrogation and improves the concentration of fluid from the sample stream that is available for post-interrogation steps (e.g., cryopreservation and/or the like).

[0088] In some embodiments, the sample fluid is introduced and/or flows through at least a portion of the microfluidic chip 100 that is higher than (e.g., positioned above) a portion of the microfluidic chip 100 which the sheath fluid flows through. [0089] At step 406, the sheath fluid and the sample fluid flow through the microfluidic chip 100. For example, the sheath fluid and the sample fluid may flow through at least a portion of the microfluidic chip 100 such that particles in the sample fluid are inertially focused. The inertial focusing may occur as a result of the sample fluid stream coming into fluid contact with the sheath fluid stream. In some embodiments, the sheath fluid and the sample fluid may flow through at least a portion of the microfluidic chip 100 such that particles in the sample come into fluid contact with one another at a junction and enter a third microchannel 124. The sheath fluid stream and the sample fluid stream may then continue to flow through the third microchannel 124. In some embodiments, the sheath fluid stream and the sample fluid stream may flow through at least a portion of the third microchannel 124 that is positioned downstream from the first microchannel 112 and the second microchannel 114. In some embodiments, the sheath fluid stream and the sample fluid stream may flow through at least a portion of the third microchannel 124 which is structured (e.g., adapted) to inertially focus particles in the sample fluid stream. For example, the sheath fluid stream and the sample fluid stream may flow through at least a portion of the third microchannel 124 which is structured (e.g., adapted) to inertially focus particles in the sample fluid stream at a single particle equilibrium position.

[0090] The foregoing method descriptions and the process flow diagrams are provided merely as illustrative examples and are not intended to require or imply that the steps of the various embodiments must be performed in the order presented. The steps in the foregoing embodiments may be performed in any order. Words such as '‘then,” “next,” etc., are not intended to limit the order of the steps; these words are simply used to guide the reader through the description of the methods. Although process flow diagrams may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, and the like. When a process corresponds to a function, the process termination may correspond to a return of the function to a calling function or a main function.

[0091] Some non-limiting embodiments of the present disclosure may be described herein in connection with a threshold. As described herein, satisfying a threshold may refer to a value being greater than the threshold, more than the threshold, higher than the threshold, greater than or equal to the threshold, less than the threshold, fewer than the threshold, lower than the threshold, less than or equal to the threshold, equal to the threshold, and/or the like. [0092] No aspect, component, element, structure, act, step, function, instruction, and/or the like used herein should be construed as critical or essential unless explicitly described as such. In addition, as used herein, the articles "a" and "an" are intended to include one or more items and may be used interchangeably with "one or more" and "at least one." Furthermore, as used herein, the term "set" is intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, etc.) and may be used interchangeably with "one or more" or "at least one." Where only one item is intended, the term "one" or similar language is used. Also, as used herein, the terms "has," "have," "having," or the like are intended to be open ended terms. Further, the phrase "based on" is intended to mean "based at least partially on" unless explicitly stated otherwise.

[0093] The various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0094] Embodiments implemented in computer software may be implemented in software, firmware, middleware, microcode, hardware description languages, or any combination thereof. A code segment or machine-executable instructions may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including memory sharing, message passing, token passing, network transmission, etc.

[0095] The actual software code or specialized control hardware used to implement these systems and methods is not limiting. Thus, the operation and behavior of the systems and methods were described without reference to the specific software code being understood that software and control hardware can be designed to implement the systems and methods based on the description herein.

[0096] When implemented in software, the functions may be stored as one or more instructions or code on a non-transitory computer-readable or processor-readable storage medium. The steps of a method or algorithm disclosed herein may be embodied in a processorexecutable software module, which may reside on a computer-readable or processor-readable storage medium. A non-transitory computer-readable or processor-readable media includes both computer storage media and tangible storage media that facilitate transfer of a computer program from one place to another. A non-transitory processor-readable storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such non-transitory' processor-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other tangible storage medium that may be used to store desired program code in the form of instructions or data structures and that may be accessed by a computer or processor. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and/or instructions on a non-transitory' processor-readable medium and/or computer-readable medium, which may be incorporated into a computer program product.

[0097] The preceding description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the following claims and the principles and novel features disclosed herein.

[0098] While various aspects and embodiments have been disclosed, other aspects and embodiments are contemplated. The various aspects and embodiments disclosed are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims

Claims

CLAIMS What is claimed is:

1. A method for producing an inertially focused sample fluid stream having a single particle equilibrium position, the method comprising: introducing a sheath fluid to a microfluidic chip; introducing a sample fluid to the microfluidic chip; and flowing the sheath fluid and the sample fluid through at least a portion of the microfluidic chip such that particles in the sample fluid are inertially focused based on the sample fluid coming into fluid contact with the sheath fluid, the sample fluid imparting a first inertial force and the sheath fluid imparting a second inertial force that is counter to the first inertial force.

2. The method of claim 1 , wherein introduction of the sample fluid forms a sample fluid stream, and introduction of the sheath fluid forms a sheath fluid stream, and wherein flowing the sheath fluid and the sample fluid through the at least a portion of the microfluidic chip comprises inertially focusing particles in the sample fluid stream based on the sheath fluid stream coming into fluid contact with the sample fluid stream.

3. The method of claim 1, wherein introducing the sample fluid into the microfluidic chip comprises introducing the sample fluid into the microfluidic chip via a first inlet corresponding to a first microchannel, and wherein introducing the sheath fluid into the microfluidic chip comprises introducing the sheath fluid into the microfluidic chip via a second inlet corresponding to a second microchannel.

4. The method of claim 3, further comprising: flowing the sample fluid stream through the first microchannel, where the first microchannel is positioned above the second microchannel, and structured to focus the sample fluid stream; flowing the sheath fluid stream through the second microchannel, where the second microchannel is positioned below the first microchannel, and sized and dimensioned to focus the sheath fluid stream; and flowing the sample fluid stream such that the sample fluid stream comes into fluid contact with the sheath fluid stream along a portion of a third microchannel at a junction, the junction defined by a fluid connection between the first microchannel and the second microchannel.

5. The method of claim 4, further comprising flowing the sample fluid stream and the sheath fluid stream through the third microchannel, wherein the third microchannel is positioned downstream from the first microchannel and the second microchannel, and wherein the third microchannel is structured to inertially focus particles in the sample fluid stream at a single particle equilibrium position.

6 The method of claim 1 , wherein flowing the sheath fluid and the sample fluid through the at least a portion of the microfluidic chip comprises: flowing the sheath fluid and the sample fluid through at least a portion of the microfluidic chip such that particles in the sample fluid are inertially focused as a result of the sample fluid coming into fluid contact with the sheath fluid.

7. A device for producing an inertially focused sample fluid stream having a single particle equilibrium position, the device comprising a microfluidic chip and being configured, in operation, to: receive a sheath fluid into a microfluidic chip; receive a sample fluid into the microfluidic chip; and flow the sheath fluid and the sample fluid through at least a portion of the microfluidic chip such that particles in the sample fluid are inertially focused based on the sample fluid coming into fluid contact with the sheath fluid.

8. The device of claim 7, wherein, when flowing the sheath fluid and the sample fluid through at least a portion of the microfluidic chip, the device is configured, in operation, to: flow the sheath fluid and the sample fluid through at least a portion of the microfluidic chip such that particles in the sample fluid are inertially focused in response to the sample fluid coming into fluid contact with the sheath fluid.

9. A method for producing an inertially focused sample fluid stream having a single particle equilibrium position, the method comprising: introducing a sheath fluid stream into a microfluidic channel; introducing a sample fluid stream into an upper portion of the microfluidic channel; and flowing the sheath fluid stream and the sample fluid stream through a downstream portion of the microfluidic channel, a structure of the dow nstream portion of the microfluidic channel being adapted to inertially focus the sample fluid stream and particles disposed in the sample fluid stream; wherein the introduction of the sample fluid stream into the upper portion of the microfluidic channel and the inertial focusing of the sample fluid stream by the structure of the downstream portion of the microfluidic channel produce an inertially focused sample fluid stream having a single particle equilibrium position.

10. A device for producing an inertially focused sample fluid stream having a single particle equilibrium position, the device having a microfluidic channel with an upper portion and a downstream portion, the device being configured, in operation, to: receive a sheath fluid stream into the microfluidic channel; receive a sample fluid stream into the upper portion of the microfluidic channel; and flow the sheath fluid stream and the sample fluid stream through the downstream portion of the microfluidic channel, the downstream portion of the microfluidic channel having a structure adapted to inertially focus the sample fluid stream and particles disposed in the sample fluid stream; wherein the inertial focusing of the sample fluid stream by the structure of the downstream portion of the microfluidic channel produces an inertially focused sample fluid stream having a single particle equilibrium position.

11. A microfluidic chip for producing an inertially focused sample fluid stream having a single particle equilibrium position, the microfluidic chip comprising: a first microchannel for regulating fluid flow between an upstream portion of the first microchannel and a downstream portion of the first microchannel, the first microchannel in fluid communication with a first inlet positioned along the upstream portion of the first microchannel; a second microchannel for regulating fluid flow between an upstream portion of the second microchannel and a dow nstream portion of the second microchannel, the second microchannel in fluid communication with a second inlet positioned along the upstream portion of the second microchannel, wherein an opening in the downstream portion of the first microchannel is mated with an opening in the downstream portion of the second microchannel to form a junction, and wherein, a lateral distance of the first microchannel that is associated with the junction is greater than a lateral distance of the second microchannel that is associated with the junction.

12 The microfluidic chip of claim 11, wherein the junction comprises a taper along a downstream portion of the junction.

13. The microfluidic chip of claim 11, wherein the downstream portion of the first microchannel is aligned with the downstream portion of the second microchannel along a common axis.

14 The microfluidic chip of claim 11, wherein, at the junction, the first microchannel and the second microchannel extend along the common axis for a distance, the distance being a distance between 200 to 300 pm.

15. The microfluidic chip of claim 11, wherein the downstream portion of the first microchannel is aligned with the downstream portion of the second microchannel along parallel axes.

16. The microfluidic chip of claim 1 1, further comprising a third microchannel in fluid communication with the first microchannel and the second microchannel at the junction.

17. The microfluidic chip of claim 16, wherein the third microchannel comprises an upstream portion and a downstream portion, and wherein the upstream portion of the third microchannel comprises a curved structure.

18. The microfluidic chip of claim 17, wherein the curved structure comprises a spiral structure.

19. The microfluidic chip of claim 18, wherein the spiral structure forms an Archimedes spiral.

20. The microfluidic chip of claim 18, wherein the spiral comprises a number of rotations, the number of rotations being between 1 rotation and 3 rotations.