EP3600667A1 - Systèmes et procédés de séparation microfluidique de canal parallèle - Google Patents

Systèmes et procédés de séparation microfluidique de canal parallèle

Info

Publication number
EP3600667A1
EP3600667A1 EP18724667.3A EP18724667A EP3600667A1 EP 3600667 A1 EP3600667 A1 EP 3600667A1 EP 18724667 A EP18724667 A EP 18724667A EP 3600667 A1 EP3600667 A1 EP 3600667A1
Authority
EP
European Patent Office
Prior art keywords
substrate
channels
microfluidic
fluid
face
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP18724667.3A
Other languages
German (de)
English (en)
Inventor
Jason Fiering
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Charles Stark Draper Laboratory Inc
Original Assignee
Charles Stark Draper Laboratory Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Charles Stark Draper Laboratory Inc filed Critical Charles Stark Draper Laboratory Inc
Publication of EP3600667A1 publication Critical patent/EP3600667A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
    • B01L3/50273—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by the means or forces applied to move the fluids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
    • B01L3/502761—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads, for physically stretching molecules
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/08—Geometry, shape and general structure
    • B01L2300/0809—Geometry, shape and general structure rectangular shaped
    • B01L2300/0816—Cards, e.g. flat sample carriers usually with flow in two horizontal directions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/08—Geometry, shape and general structure
    • B01L2300/0861—Configuration of multiple channels and/or chambers in a single devices
    • B01L2300/0864—Configuration of multiple channels and/or chambers in a single devices comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/08—Geometry, shape and general structure
    • B01L2300/0861—Configuration of multiple channels and/or chambers in a single devices
    • B01L2300/0867—Multiple inlets and one sample wells, e.g. mixing, dilution
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/08—Geometry, shape and general structure
    • B01L2300/0861—Configuration of multiple channels and/or chambers in a single devices
    • B01L2300/0874—Three dimensional network
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/08—Geometry, shape and general structure
    • B01L2300/0887—Laminated structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2400/00—Moving or stopping fluids
    • B01L2400/04—Moving fluids with specific forces or mechanical means
    • B01L2400/0403—Moving fluids with specific forces or mechanical means specific forces
    • B01L2400/0433—Moving fluids with specific forces or mechanical means specific forces vibrational forces
    • B01L2400/0436—Moving fluids with specific forces or mechanical means specific forces vibrational forces acoustic forces, e.g. surface acoustic waves [SAW]

Definitions

  • Chimeric Antigen Receptor T-cell therapies can use genetically engineered I-cells re-infused into the patient to recognize and kill cancer cells.
  • the first step can be to isolate the I-cells from a sample of the patient's blood.
  • the blood sample can typically be a 300-400 ml product enriched in white blood cells (leukapheresis), which can still include only about 1 % of the target T-cells.
  • the current isolation practice can involve laborious centrifugal separation under highly controlled conditions, which can damage the blood cells.
  • the present solution can reduce costs and increase access to life-saving therapy by purifying lymphocytes, including T-cells, from patient blood samples.
  • the present solution can acoustically separate lymphocytes at rates of 2 ml/min or higher.
  • the present solution provides a polystyrene acoustophoretic device that can accept standard leukapheresis product with only 1 : 1 dilution and is tunable.
  • the system In a high-recovery mode, the system can recover about 72% of lymphocytes with 90.4% purity.
  • the system In a high-purity mode, the system can recover about 43%o of lymphocytes with a 96.8%> purity.
  • the performance of the present device can exceed that achieved by existing centrifugal methods.
  • the present solution can also achieve between about 80% and about 90% red blood cell (RBC) separation at rates between about 0.5 and about 2 mL/min.
  • RBC red blood cell
  • the multi-channel system can include multiple channels separated by air gaps to substantially prevent acoustic coupling of neighboring channels.
  • the system can also include distribution and collection manifolds that distribute blood from a main inlet to each of the channels and collect the outflow to two outlets.
  • the two collection manifolds to the two outlet can be fabricated on opposing faces of a substrate and connected by holes penetrating the substrate.
  • a separation device can include a first substrate, a second substrate, and a third substrate.
  • the first substrate can include a first plurality of microfluidic channels that are defined in a first face of the first substrate.
  • Each of the first plurality of microfluidic channels can include an upstream portion and a downstream portion.
  • the second plurality of microfluidic channels can be defined in a second face of the first substrate.
  • Each of the second plurality of microfluidic channels can include an upstream portion and a downstream portion.
  • the first substrate can include a plurality of via channels coupling the downstream portion of the first plurality of microfluidic channels to the upstream portion of the second plurality of microfluidic fluid channels.
  • the second substrate can be coupled with the first face of the first substrate.
  • the second substrate can define a wall of the first plurality of microfluidic fluid channels.
  • the third substrate can be coupled with the second face of the first substrate.
  • the third substrate can define a wall of the second plurality of microfluidic fluid channels.
  • the first, second, or third substrate can be configured to couple with a base substrate comprising one or more acoustic transducers.
  • the first substrate can include an isolation slot that is positioned between each of the first plurality of microfluidic fluid channels.
  • Each of the one or more acoustic transducers can protrude perpendicular to a face of the base substrate and into the isolation slot positioned between each of the first plurality of microfluidic fluid channels.
  • the isolation slots can be positioned between each of the first plurality of microfluidic fluid channels run substantially parallel to and the entire length of the first plurality of microfluidic channels.
  • the device can also include the base substrate that can include the one or more acoustic transducers. Each of the one or more acoustic transducers can be coupled with the second face (or other free face) of the first substrate.
  • the downstream portion of the each of the first plurality of microfluidic fluid channels can include a first outlet that is positioned substantially along a longitudinal axis.
  • the downstream portion of the each of the first plurality of microfluidic fluid channels can include a second outlet positioned adjacent to a lateral wall of the first outlet.
  • the first substrate can define a manifold that is configured to distribute a fluid to the first plurality of microfluidic fluid channels.
  • the manifold can include a network of biomimetic channels.
  • a distribution portion of the manifold can be defined in the first face of the first substrate and a collection portion of the manifold can be defined in the first face and the second face of the first substrate.
  • each of the plurality of microfluidic separation channels also include a first wall that has a first thickness and a second wall opposite the first wall that has a second thickness.
  • the first thickness and the second thickness are equal to c s (f)/4f, or an odd multiple thereof, where c s (f) is a frequency dependent speed of a shear wave through the plastic.
  • the second thickness is different than the first thickness.
  • the first thickness is about c w /4f + d
  • the second thickness is about c w /4f- d
  • a lateral width of each of the of microfluidic separation channels is about c/2f, where c w is an odd multiple of an acoustic velocity of an acoustic wave in the plastic substrate, c/is an acoustic velocity of the acoustic wave in a fluid flowing through each of the plurality of microfluidic separation channels, /is an operating frequency of the acoustic wave, and d is a width increment defined by c/16f ⁇ d ⁇ c/4f.
  • a method can include providing a fluid cleansing device.
  • the device can include a first substrate, a second substrate, and a third substrate.
  • the first substrate can include a first plurality of microfluidic channels that are defined in a first face of the first substrate.
  • Each of the first plurality of microfluidic channels can include an upstream portion and a downstream portion.
  • the second plurality of microfluidic channels can be defined in a second face of the first substrate.
  • Each of the second plurality of microfluidic channels can include an upstream portion and a downstream portion.
  • the first substrate can include a plurality of via channels coupling the downstream portion of the first plurality of microfluidic channels to the upstream portion of the second plurality of microfluidic fluid channels.
  • the second substrate can be coupled with the first face of the first substrate.
  • the second substrate can define a wall of the first plurality of microfluidic fluid channels.
  • the third substrate can be coupled with the second face of the first substrate.
  • the third substrate can define a wall of the second plurality of microfluidic fluid channels.
  • the first, second, or third substrate can be configured to couple with a base substrate comprising one or more acoustic transducers.
  • the method can include flowing a fluid that includes particles through the first plurality of microfluidic channels.
  • the method can include directing, with an acoustic wave generated by the one or more acoustic transducers, the particles to a first aggregation axis of each of the first plurality of
  • microfluidic channels are microfluidic channels.
  • the method can include flowing the fluid through a manifold defined in the first substrate.
  • the manifold can include a network of biomimetic channels.
  • the method can include flowing the fluid through a distribution portion of the manifold that is defined in the first face of the first substrate.
  • the method can include collecting at least a portion of the fluid at a collection portion of the manifold defined in the first face and the second face of the first substrate.
  • the first substrate can include an isolation slot positioned between each of the first plurality of microfluidic fluid channels.
  • Each of the one or more acoustic transducers can protrude perpendicular to a face of the base substrate and into the isolation slot positioned between each of the first plurality of microfluidic fluid channels.
  • One or more acoustic transducers can extend laterally along the base substrate and parallel to the first substrate.
  • FIG. 1 illustrates an example system for separating contents of a fluid.
  • FIG. 2 illustrates an example implementation of the system for separating contents of a fluid.
  • FIG. 3 illustrates an example microfluidic flow chamber that can be used in the system illustrated in FIG. 1.
  • FIG. 4 illustrates a wire frame detail of the collection manifold from the collection manifold illustrated in FIG. 3.
  • FIG. 5 illustrates a section view of the wire frame model illustrated in FIG. 4.
  • FIGS. 6-8 illustrate the modeled wall shear rates experienced within the microfluidic flow chamber illustrated in FIG. 3.
  • FIG. 9 illustrates the wall shear rates experienced in the transition between via channels and the collection channel.
  • FIG. 10 illustrates the fluid velocity experienced in the transition between the via channels and the collection channel.
  • FIGS. 11 and 12 illustrate plots of streamlines through the transition from the via channels to the collection channels.
  • FIG. 13 illustrates a top view schematic of an example microfluidic flow chamber can be used in the system illustrated in FIG. 1.
  • FIG. 14 illustrates an isometric view of an example base substrate to which the microfluidic flow chamber illustrated in FIG. 13 is to be coupled.
  • FIG. 15 illustrate a top view schematic of another example microfluidic flow chamber as can be used in the system illustrated in FIG. 1.
  • FIG. 16 illustrates an isometric view of an example base substrate to which the microfluidic flow chamber illustrated in FIG. 15 is to be coupled.
  • FIG. 17 illustrate a cross-sectional view of an example microfluidic flow chamber can be used in the system illustrated in FIG. 1.
  • FIG. 18 illustrates a cross-sectional view of an example microfluidic flow chamber with symmetrical walls as can be used in the system illustrated in FIG. 1.
  • FIG. 19 illustrates a cross-sectional view of an example microfluidic flow chamber with asymmetrical walls as can be used in the system illustrated in FIG. 1.
  • FIG. 20 illustrates a top view and cross-sectional view of an example microfluidic flow chamber with asymmetrical walls as can be used in the system illustrated in FIG. 1.
  • FIGS. 21 and 22 illustrates a flow chart of an example method of cleansing a fluid using the system illustrated in FIG. 1.
  • FIG. 1 illustrates an example system 100 for separating the contents of a fluid.
  • blood or another fluid to be processed
  • the blood is removed from a patient 101 via an intravenous line 102.
  • the blood is then pumped to a mixing chamber 104 by a pump 103.
  • capture particles are mixed with the blood.
  • the components of the capture particles are stored in a reservoir 115.
  • the capture particles are pumped by a pump 106 into the mixing chamber.
  • the blood and capture particles enter a manifold system 107.
  • the manifold system 107 distributes the blood and capture particles to a plurality of separation channels contained within the microfluidic flow chamber 108.
  • the microfluidic flow chamber 108 includes one or more piezoelectric acoustic transducers 109.
  • the acoustic waves generated by the acoustic transducers 109 are used to funnel the contents of the blood and capture particles to specific outlets of the separation channels.
  • the patient 101 can be replaced with fluid reservoir or tank.
  • the patient's blood can be pre-drawn from the patient 101 and then processed by the system 100 at a later time.
  • the system 100 can be used to separate the components from a fluid other than blood and the fluid can be stored in a reservoir and be processed with the system 100.
  • the cleansed blood flows to a first outlet 110.
  • the blood After exiting the first outlet 110, the blood returns to the patient 101, via a second intravenous line 111.
  • the capture particles and other waste material removed from the blood exit the microfluidic flow chamber 108 via a second outlet 112.
  • the waste material and capture particles enter a waste collection unit 113.
  • the capture particles are separated from the waste material. Once separated, the waste material is discarded and the capture particles are returned to the reservoir 115 by tubing 114. Once returned to the reservoir 115, the capture particles are reused in the system to remove additional waste material from whole blood as it continues to flow through the system 100.
  • the system 100 includes a pump 103 for moving blood from the patient 101 to the mixing chamber 104.
  • the pump operates continuously, while in other implementations the pump works intermittently, and only activates when the level of whole blood in the mixing chamber 104 or manifold falls below a set threshold.
  • the flow rate of the pump is configurable, such that the rate the blood exits the patient can be configured to be faster or slower than if no pump was used. In yet other implementations, no external pump is required.
  • the blood is transported to the mixing chamber 104 by the pressure generated by the patient's own heart.
  • flow or pressure is monitored in the network, and these measurements in turn control the pump.
  • Example pumps can include, but are not limited, to peristaltic pumps, impeller pumps or any other pump suitable for flowing blood.
  • capture particles are also pumped into the mixing chamber 104.
  • the capture particles are polystyrene beads or liposomes encapsulating an acoustically active fluid.
  • the capture particles are described in greater detail below.
  • a pump 106 pumps the capture particles from a reservoir 115 to the mixing chamber 104.
  • affinity particles embedded within the surface of the capture particles bind to undesired particles, cells, or toxins to be removed from the blood.
  • the capture particles are injected into the mixing chamber 104.
  • the capture particles are injected into the manifold system 107 or directly into the separation channels of the microfluidic flow chamber 108.
  • the system 100 does not use capture particles.
  • the components (e.g., red blood cells) of the fluid to be cleansed may be intrinsically acoustically active.
  • cells or other objects may have an acoustic contrast factor sufficiently different than that of the blood or other fluid and are therefore "acoustically active.” These cells or other objects can be directed with the acoustic transducer 109.
  • the blood containing undesirable particles and the capture particles enter the mixing chamber 104.
  • the contents of the mixing chamber are continuously agitated to improve distribution of the capture particles throughout the blood and undesirable particles such that the capture particles bind to the undesirable particles.
  • anticoagulants or blood thinners are introduced into the mixing chamber 104 to assist the blood as it flows through the system 100.
  • the mixing chamber 104 contains a heating element for warming the contents of the mixing chamber 104.
  • the contents of the mixing chamber 104 then flow into the manifold system 107, as illustrated by system 100.
  • the manifold system 107 is described further in relation to FIGS. 3-12, among others.
  • the manifold system 107 flows the blood, undesirable particles, and capture particles into the inlets of the plurality of separation channels of the microfluidic flow chamber 108.
  • multiple microfluidic flow chambers described herein are stacked to process relatively large volumes of blood or other fluids.
  • the manifold system 107 distributes the blood to each of the separation channels of the stacked microfluidic flow chambers.
  • the manifold system 107 is configured to distribute shear sensitive fluids, such as blood, to each of the separation channels without damaging the shear sensitive fluids. In some implementations, the manifold system 107 is also configured to receive the shear sensitive fluid from the microfluidic flow chamber 108 after the fluid has flowed through the microfluidic flow chamber 108.
  • the manifold can include biomimetic features.
  • the manifold can include gradual curving channels rather than right angles.
  • the biomimetic features can include channels within the manifold that mimic vascular channels. For example, the channels split at bifurcations. After a bifurcation the size of the channel is reduced according to Murray's Law.
  • the manifold includes trunk and branch channels, where supply channels flowing to each of the microfluidic flow chambers branch from a main supply trunk. Additional information regarding the biomimetic manifold system 107 can be found in U.S.
  • the system 100 can also include a collection manifold that condenses the plurality of separation channels of the stacked microfluidic flow chambers into the first outlet 111 and the second outlet 112, which can also be referred to as collection channels.
  • the system 100 can include multiple collection and input manifolds that can each collect or supply fluid to a portion of the separation channels.
  • the microfluidic flow chamber 108 contains a plurality of separation channels.
  • the microfluidic flow chamber 108 and separation channels are described further in relation to FIGS. 3-20, among others.
  • the capture particles and undesirable particles are driven with standing acoustic waves to outlets.
  • the acoustic wave is activated intermittently. In some implementations, the separation occurs during a single stage, while in other implementations, the separation occurs over a plurality of stages. In some implementations, the microfluidic flow chamber is disposable.
  • the microfluidic flow chamber 108 sits atop an acoustic transducer 109.
  • the system 100 contains a single acoustic transducer 109, while in other implementations the system 100 contains a plurality of acoustic transducers 109.
  • the acoustic transducer 109 is glued to the microfluidic flow chamber 108.
  • the microfluidic flow chamber 108 is clamped to the acoustic transducer 109 so the microfluidic flow chamber may easily be removed from the system.
  • the adhesive material connecting the acoustic transducer 109 to the microfluidic flow chamber 108 is removable, for example by heating the adhesive.
  • the acoustic transducer 109 imposes a standing acoustic wave on the separation channels of the microfluidic flow chamber 108 transverse to the flow of the fluid within the microfluidic flow chamber 108.
  • the standing acoustic waves are used to drive fluid constituents towards or away from the walls of the separation channels or other aggregation axes.
  • the dimensions of the separation channels are selected based on the wavelength of the imposed standing wave such that pressure nodes are generated in each of the separation channels.
  • the capture particles are driven to different positions within the separation channels based on the sign of their acoustic contrast factor at a rate which is proportional to the magnitude of their contrast factor.
  • Capture particles or other elements with a positive contrast factor e.g. the formed elements of blood
  • elements with a negative contrast factor are driven toward the pressure antinodes.
  • formed elements of blood can be separated from capture particles (and thus the undesirable particles bound to the capture particles).
  • capture particles can be selected to have negative contrast factors, which is opposite to the positive contrast factors of the formed elements of blood.
  • the formed elements are driven towards the resulting pressure node while the capture particles are driven towards the antinodes.
  • one type of blood cell can be separated from another because of the differing size, density, or compressibility of the cell types.
  • lymphocytes may be separated from other white blood cells, red blood cells, and platelets.
  • analytes, diseased cells, or pathogenic cells, including bacteria can be separated from normal blood cells.
  • the cleansed blood exits the microfluidic flow chamber 108 at a first outlet 110. From there the blood is returned to the patient 101 via an intravenous supply line 111.
  • the blood in the supply line 111 is reheated to body temperature before returning to the patient 101.
  • an infusion pump is used to return the blood to the patient 101, while in the system 100 the pressure generated in the system by pumps 103 and 106 is adequate to force the blood to return to the patient 101.
  • waste material e.g. the capture particle and undesirable particles
  • the waste collection unit 113 contains a capture particle recycler.
  • the capture particle recycler unbinds the undesirable particles from the capture particles.
  • the capture particles are then returned to the reservoir 115 via tubing 114.
  • the undesirable particles are then disposed of.
  • the undesirable particles are saved for further testing.
  • the microfluidic flow chamber 108 can be used for other methods than blood cleansing such as, but not limited to, apheresis and analytical sample preparation.
  • the microfluidic flow chamber 108 can be used to flow extract a desired fraction of cells or particles from a sample or to remove particles or cells to leave purified liquid fraction.
  • system 100 can be used to cleanse stored blood or other stored fluids.
  • the system 100 can be used to cleanse collected blood for later infusion to help ensure the safety of the blood or it can be used to prepare blood for analysis.
  • FIG. 2 illustrates one example implementation of the system for separating contents of a fluid.
  • the system includes the microfluidic flow chamber 108.
  • the microfluidic flow chamber 108 can be positioned against the acoustic transducer 109.
  • the temperature of the acoustic transducer 109 is controlled via a heat sink 120 and a peltier device 122.
  • the heat sink 120 and the peltier device 122 can prevent the acoustic transducer 109 from overheating the blood flowing through the microfluidic flow chamber 108 and maintain the temperature of the blood in or near physiological temperature ranges.
  • the system can also include a heat exchanger 124.
  • the heat exchanger 124 aid in dissipation of heat generated by the transducer.
  • the acoustic transducer 109, heat sink 120, and peltier device 122 can be components of a base substrate.
  • FIG. 3 illustrates an example microfluidic flow chamber 108 that can be used in the example implementation of the system illustrated in FIGS. 1 and 2.
  • the microfluidic flow chamber 108 includes a first substrate 201(1), a second substrate 201(2), and a third substrate 201(3), which can be generally referred to as substrates 201.
  • the substrate 201(2) includes a plurality of separation channels 202.
  • the substrate 201(2) also includes the distribution manifold 702 and the collection manifold 704, which can be implementations of the manifold system 107 illustrated in FIG. 1.
  • the distribution manifold 702 can include a feed channel 205 that can serve as a trunk to the distribution manifold 702.
  • the feed channel 205 can branch into a plurality of inlets 203 that form the start of the separation channels 202.
  • the separation channels 202 can branch to form a plurality of outlets 204.
  • the separation channels 202 can branch to form a central and two lateral outlets.
  • the outlets 204 can be a component of the collection manifold 704.
  • the distribution manifold 702 can be defined in a first face of the substrate 201(1).
  • the collection manifold 704 can be defined in the first face and a second face of the substrate 201(1). Each portion of the collection manifold 704 that is defined in a different face of the substrate 201(1) can form a collection manifold for one or more of the channels out lets 204.
  • each channel 202 can include one or more outlets 204 that collect the focused particles, which can exit to a collection manifold on first face of the substrate 201(1) and each channel 202 can include one or more outlets 204 that collect the fluid substantially free of the focused particles, which can exit to a collection manifold on the second face of the substrate 201(1).
  • the distribution manifold 702 can include portions defined in the first face and the second face of the substrate 201(2). For example, the portion of the distribution manifold 702 defined on one face can feed the separation channels 202 with the fluid from which the particles are to be removed. The portion of the distribution manifold 702 defined on another face of the substrate 201(2) can feed a buffer fluid into separation channels 202.
  • the separation channels 202 can include three inlets.
  • the central inlet can supply a buffer fluid to the separation channel 202.
  • the lateral inlets can supply the blood (or other fluid from which the particles are to be remove) toward the lateral walls of the separation channels 202.
  • the acoustic wave can drive the blood cells (or other acoustically active particles) into the buffer flowing through the central portion of the separation channel 202.
  • the microfluidic flow chamber 108 can include three substrates 201.
  • the microfluidic flow chamber 108 can include more than three substrates 201 or can include fewer than three substrates 201.
  • the microfluidic flow chamber 108 can include a stacked configuration that includes a plurality of substrates 201 that include channels 202.
  • the channels 202 of the microfluidic flow chamber 108 can be machined into the faces of the substrate 201(2).
  • the channels 202 can be created in the face of the substrates 201 using, for example, direct lithography, photopatternable resists, injection molding, direct micromachining, deep reactive ion etching (RIE), hot embossing, or any combinations thereof.
  • RIE deep reactive ion etching
  • the top substrate 201(1) can form a wall (e.g., a ceiling) of the channels 202 machined into the top face of the substrate 201(2) and the bottom substrate 201(3) can form a wall (e.g., a floor) of the channels 202 machined into the bottom of the substrate 201(2).
  • the substrates 201 can be coupled together with, for example, thermocompression bonding, mechanical coupling (e.g., clamps), adhesives, or epoxies.
  • the channels 202 can also be machined into the top substrate 201(1) and the bottom substrate 201(3).
  • the bottom substrate 201(3) can divided into multiple parts or can be cut away in the region of the separation channels 202 in order to avoid interfering with the acoustic properties of the separation channels or to avoid interfering with the coupling of the transducer to the substrates.
  • the transducer is coupled to a face of the substrate 201(1) and in others it is coupled to a face of the substrate 201(2).
  • the channels 202 machined into the top face of the substrate 201(1) can be fluidically coupled with the channels 202 machined into the bottom face of the substrate 201(1) through via channels.
  • the via channels can also be referred to as translation channels, connecting channels, microfluidic channels, or channels.
  • the distribution manifold 702 is machined into the top face of the substrate 201(2).
  • the distribution manifold 702 can include the feed channel 205 that branches into the inlets 203 and the separation channels 202.
  • the separation channels 202 can then branch into the central and lateral outlets 204.
  • the central outlet 204 can be machined into the top face of the substrate 201(2) and can feed into the collection channel 206(b) of the collection manifold 704.
  • the lateral outlets 204 can be coupled with the collection channel 206(a) of the collection manifold 704.
  • the lateral outlets 204 can be pass through the via channels to channels machined in the bottom face of the substrate 201(2), which can then feed the collection channels 206(a).
  • FIG. 4 illustrates a wire frame model of a detail of the collection manifold 704 from the collection manifold 704 illustrated in FIG. 3.
  • FIG. 5 illustrates a different view of the wire frame model illustrated in FIG. 4.
  • the separation channels 202 branch into the central and lateral outlets 204.
  • the neighboring central outlets 204 can merge and flow into the first collection channel 206(b) that is machined into the top face of the substrate 201(2).
  • more than two central outlets 204 can merge and flow into a first collection channel 206(b).
  • the collection manifold 704 can include a plurality of collection layers.
  • 20 central outlets 204 can merge into 10 different collection channels of a first collection layer, which can merge into 5 different collection channels of a second collection layer.
  • the collection channels can continue to merge until a single collection channel remains as an output.
  • a plurality of collection channels 206(b) can branch serially off of an outlet trunk as illustrated in FIG. 3.
  • the lateral outlets 204 can pass to a collection channel 206(a) formed in the bottom face of the substrate 201(2) by via channels 802.
  • the via channels 802 can fluidically couple channels machined into a first face of a substrate 201 to channels machined into a second face of the substrate 201.
  • the via channels 802 can coupled the lateral outlets 204 formed in the top face of the substrate 201(2) with the collection channel 206(a) formed in the bottom face of the substrate 201(2).
  • the via channels 802 can enable fluid routing in the microfluidic flow chamber 108.
  • the via channels 802 can enable fluid routing in a substrate 201 such that collection channel 206(b) and 206(a) can cross each other without intersecting.
  • the middle outlet 204 can continue to flow on a first face of the substrate 201(2) and into a collection channel 206(b) that is machined into the first face of the substrate 201(2).
  • the lateral outlets 204 can each flow into a via channel 802 and into a collection channel 206(a) that is machined into a second face of the substrate 201(2).
  • the via channels 802 can be manufactured by drilling through the substrate 201 at a predetermined angle 803.
  • the via channels 802 can be laser or mechanically drilled through the substrates 201.
  • the predetermined angle 803 can be between about 10° and about 80°, between about 15° and about 75°, between about 20° and about 70°, between about 25° and about 65°, between about 30° and about 60°, between about 35° and about 55°, or between about 40° and about 50°. In some cases, the predetermined angle 803 is about 45°.
  • the predetermined angle 803 can be less than 45°.
  • the predetermined angle 803 can be selected based on the fluid flowing through the channels.
  • FIGS. 6-8 illustrate the modeled wall shear rates experienced within the microfluidic flow chamber 108.
  • FIG. 6 illustrates the trifurcation from the channel 202 to the central and lateral outlets 204.
  • FIGS. 7 and 8 illustrate the modeled wall shear rates experienced near the via channels 802.
  • the via channels 802 experience relatively greater wall shear rates than the collection channel 206(a). In all cases however, the shear rates are acceptable because they are below the threshold that would be expected to damage blood cells.
  • the effective diameters of the central and lateral outlets and the diameters of the via channels 802 can be adjusted to improve uniformity of shear throughout the manifolds. To enable bubbles to pass through the microfluidic chamber 108, the diameters of the via channels 802 can be larger than the width of the of lateral outlets 204 and smaller than the width of the collection channels 206 with which they intersect.
  • FIGS. 9 and 10 illustrate the wall shear rates and fluid velocity, respectively, experienced in the transition between the via channels 802 and the collection channel 206(a).
  • FIGS. 9 and 10 illustrate the shear and velocity is low in the "backstep" portion of the transition.
  • the transition can be configured to reduce trauma to the blood flowing though the transition; however, the transition is configured such that the shear and velocity are not too low in the backstep (and other portions of the microfluidic flow chamber) as to generate areas of stagnation where clots can form or areas of recirculating flow.
  • the via channels 802 and the channels can be manufactured such that a "backstep" is not formed.
  • FIGS. 11 and 12 illustrate plots of streamlines through the transition from the via channels 802 to the collection channels 206(a). As illustrated, the transition is configured to not include recirculating or stagnate flow that can cause clotting or other issues with flow through the microfluidic flow chamber 108.
  • FIG. 13 illustrate a top view schematic of an example microfluidic flow chamber 108 as can be used in the system 100 illustrated in FIG. 1 and 2.
  • the microfluidic flow chamber 108 includes a substrate 201.
  • the substrate 201 defines a plurality of separation channels 202.
  • Each of the separation channels 202 includes an inlet 203 and multiple outlets 204.
  • Each inlet 203 is coupled to a feed channel 205, and each of the outlets 204 are coupled to a collection channel 206.
  • the microfluidic flow chamber 108 includes a first collection channel 206(a) and a second collection channel 206(b).
  • the substrate 201 also defines a plurality of isolation slots 207.
  • the acoustic transducers 208 protrude from a base substrate below the substrate 201 and project through isolation slots 207.
  • the substrate 201 can be configured to couple with the base substrate.
  • the substrate 201(3) can include a plurality of alignment markers that are configured to receive posts or protrusions from the base substrate.
  • the substrate 201 defines the separation channels 202 and the isolation slots 207.
  • the substrate 201 includes rigid materials such as silicon, glass, metals, or other materials that establish a high acoustic contrast between the fluid flowing though the separation channels 202 and the substrate 201.
  • the substrate 201 includes relatively more elastic materials, which establish a lower acoustic contrast between the fluid flowing the separation channels 202 and the substrate 201.
  • These materials can include thermoplastics, such as, polystyrene, acrylic (polymethylmethacrylate ), polysulfone, polycarbonate, polyethylene, polypropylene, cyclic olefin copolymer, silicone, liquid crystal polymer, and polyvinylidene fluoride.
  • the substrate 201 of the microfluidic flow chamber 108 includes multiple separation channels 202.
  • the separation channels 202 are formed into an array of separation channels 202.
  • the array of separation channels 202 can include between about 2 and about 100, between about 2 and about 50, between about 10 and about 40, or between about 20 and about 30 separation channels.
  • the inlet 203 of each of the separation channels 202 is coupled to the feed channel 205 that provides fluid to each of the separation channels 202.
  • the feed channel 205 and the separation channels 202 can be configured in a trunk and branch configuration. For example, as illustrated in FIG. 13, the feed channel 205 can narrow as separation channels 202 branch off the feed channel 205.
  • the trunk and branch configuration can also include smooth and gradual transitions between the feed channel 205 and each of the separation channels 202.
  • the transitions between the feed channel 205 and the separation channels 202 are configured to reduce or prevent damage to blood flowing through the microfluidic flow chamber 108 and to prevent clotting.
  • the feed channel 205 receives fluid from the manifold system described herein.
  • the separation channels 202 are configured to branch into multiple outlets 204 toward their downstream end. As illustrated, the separation channels 202 include a central outlet and two lateral outlets (generally referred to as outlets 204).
  • the two lateral outlets of each separation channel 202 are coupled to the collection channel 206(a), and the central outlet of each separation channel 202 is couple to the collection channel 206(b).
  • the transitions between the separation channels 202 and the collection channels 206(a) and 206(b) are smooth and gradual.
  • the capture particles are aligned toward an aggregation axis that is along a central axis of each of the separation channels.
  • the fluid flowing into the central outlet 204 is enriched with the capture particles, and the fluid flowing into the lateral outlets 204 is depleted of the capture particles.
  • the capture particles are aligned toward the walls of each of the separation channels 202 by the acoustic transducers 208.
  • the fluid flowing into the lateral outlets 204 is enriched with the capture particles and the fluid flowing into the central outlet 204 is depleted of the capture particles.
  • the undesirable cells are aligned toward an aggregation axis that is along a central axis of each of the separation channels.
  • the fluid flowing into the central outlet 204 is enriched with undesirable cell types, and the fluid flowing into the lateral outlets 204 is enriched with the desired cell type.
  • the undesirable cells are aligned toward the walls of each of the separation channels 202 by the acoustic transducers 208.
  • the fluid flowing into the lateral outlets 204 is enriched with the undesirable cells and the fluid flowing into the central outlet 204 is enriched with the desired cell type.
  • the collection channel 206(b) is in a different plane than the separation channels 202 and the collection channel 206(a).
  • the collection channel 206(b) is coupled to each of the central outlets 204 by a fluidic via between the plane of the separation channels 202 and the collection channel 206(b).
  • the collection channel 206(b) is in the same plane as the central outlets 204 and the collection channel 206(a) is in a different plane than the lateral outlets 204 and separation channels 202.
  • the microfluidic flow chamber 108 illustrated in FIG. 13 also includes a plurality of isolation slots 207.
  • the isolation slots 207 are channels that run parallel to the separation channels 202.
  • the isolation slots 207 have a height equal to the thickness of the substrate 201 and form air gaps through the substrate 201 between adjacent separation channels 202.
  • the isolation slots 207 can be milled or cut through the substrate 201.
  • the air gaps between the adjacent separation channels 202, as provided by the isolation slots 207 isolate the acoustic effects of waves from the acoustic transducers 208 to specific separation channels 202.
  • the isolation slots 207 run substantially the entire length of the separation channels 202, and in other implementations, the isolation slots 207 run along a length of the separation channels 202 only near the acoustic transducers 208.
  • Each of the substrates 201 can include isolation slots 207 or a subset of the substrates 201 can include the isolation slots 207.
  • the substrate 201(1) and the substrate 201(2) can include the isolation slots 207.
  • the isolation slots 207 are between about 100 ⁇ and about 5 mm, between about 200 ⁇ and about 3 mm, between about 300 ⁇ and about 2 mm, or between about 500 ⁇ mm and about 1 mm wide.
  • the separation channels 202 are between about 1 cm and about 10 cm, about 2 cm and about 8 cm, or about 3 cm and about 5 cm long.
  • the acoustic transducers 208 can couple with a portion of the substrate 201(2) exposed by a gap in the substrate 201(3) or the acoustic transducers 208 can be coupled to the substrate 201(3).
  • the acoustic transducers 208 are, for example, piezoelectric transducers as described above in relation to FIG. 1.
  • Each of the acoustic transducers 208 are configured to imposes a standing acoustic wave on one of the separation channels 202 of the microfluidic flow chamber 108. The standing acoustic wave is applied transverse to the flow of the fluid through the separation channels 202.
  • the standing acoustic waves generate pressure nodes and pressure antinodes within the separation channels 202 that drive the capture particles towards or away from the walls of the separation channels 202 or toward other aggregation axes.
  • the acoustic wave may be applied continuously or intermittently.
  • FIG. 14 illustrates an isometric view of an example base substrate 210 to which the microfluidic flow chamber 108, illustrated in FIG. 13, can be coupled.
  • the base substrate 210 includes the acoustic transducers 208, which are powered via electrical traces 212.
  • the base substrate 210 includes a plurality of orientation markers 214.
  • the base substrate 210 also include clamps 216 to clamp a microfluidic flow chamber to the base substrate 210.
  • the microfluidic flow chamber 108 can be coupled with the acoustic transducers 208 and the clamps clamp the acoustic transducers 208 to the base substrate 210.
  • the acoustic transducers 208 are mounted to the base substrate 210.
  • the acoustic transducers 208 project perpendicular to the base substrate 210. As illustrated in FIG. 13, when the microfluidic flow chamber 108 is coupled to the base substrate 210 each of the acoustic transducers 208 project into one of the isolation slots 207.
  • the acoustic transducers 208 are coupled to one the walls of the of the isolation slots 207, which is a shared wall with one of the adjacent separation channels 202.
  • the acoustic transducers 208 can be coupled to the inner walls of the isolation slots 208 by glycerol, glue, film, gel, or other material configured to efficiently transfer waves from the acoustic transducers 208 to the inner wall of the isolation slots 207.
  • the base substrate 210 includes a plurality of electrical traces 212.
  • the electrical traces 212 provide power to and ground each of the acoustic transducers 208.
  • the electrical traces 212 terminate in a multi-pin electrical connector that enable each of the acoustic transducers 208 to be controlled independently of one another.
  • the base substrate 210 also includes a plurality of orientation markers 214.
  • the orientation markers 214 are raised pins positioned towards each of the corners of the base substrate 210.
  • the bottom of the substrate 201 illustrated in FIG. 13 includes recesses that mate with each of the orientation markers 214.
  • the orientation markers 214 can ensure the substrate 201 is properly aligned with the base substrate 201 - therefore ensuring the acoustic transducers 208 are properly aligned with the separation channels 202.
  • the base substrate 210 also includes clamps 216. As illustrated, the clamps 216 are illustrated in their closed (or clamped) position. Once the substrate 201 is placed on the base substrate 210 and properly orientated using the orientation markers 214, the clamps 216 are closed to reversibly couple the substrate 201 to the base substrate 210. In some
  • the base substrate 210 includes a clamp 216 on each of its four sides rather than just two sides as illustrated in FIG. 14.
  • FIG. 15 illustrates a top view of an example microfluidic flow chamber 108.
  • the microfluidic flow chamber 108 includes a substrate 201.
  • the substrate 201 defines a plurality of separation channels 202.
  • Each of the separation channels 202 includes an inlet 203 and multiple outlets 204.
  • Each inlet 203 is coupled to a feed channel 205, and each of the outlets 204 are coupled to a collection channel 206.
  • the microfluidic flow chamber 108 includes a first collection channel 206(a) and a second collection channel 206(b).
  • the substrate 201 also defines a plurality of isolation slots 207.
  • the microfluidic flow chamber 108 can couple with or include acoustic transducers 221.
  • the acoustic transducers 221 lie flat on a base substrate (not shown) below the substrate 201.
  • the acoustic transducer 221 are coupled to a bottom wall of each of the separation channels 202.
  • FIG. 16 illustrates an isometric view of an example base substrate 222 to which the microfluidic flow chamber 108, illustrated in FIG. 15, is coupled.
  • the base substrate 222 includes the acoustic transducers 221, which are powered via the electrical traces 212.
  • the base substrate 222 includes a plurality of orientation markers 214.
  • the base substrate 222 also include claims 216 to clamp a microfluidic flow chamber to the base substrate 210.
  • the clamps 216, orientation markers 214, and electrical traces 212 can be similar to those described above.
  • the acoustic transducers 221 lie flat on the base substrate 222 and are configured to project an acoustic wave upward into the separation channels 202 of the microfluidic flow chamber 108.
  • the microfluidic flow chamber 108 includes recesses to receive the acoustic transducers 221, enabling the acoustic transducers 221 to provide an orientation function similar to the orientation markers 214.
  • a single, larger acoustic transducer 221 is coupled to the base substrate 222 rather than a plurality of smaller acoustic transducers 221.
  • FIG. 17 illustrates a cross-sectional view of an example microfluidic flow chamber 300.
  • the microfluidic flow chamber 300 includes three separation channels 302 that are defined within a plastic substrate 304. Each adjacent separation channel 302 is separated by an isolation slot 306.
  • the substrate 304 that defines the separation channels 302 and the isolation slots 306 sits atop a base substrate 308.
  • An acoustic transducer 208 is coupled to an inner wall of each of the isolation slots 306.
  • a heat sink 312 is coupled to each of the acoustic transducers 208.
  • the substrate that defines the separation channels 302 can have a thickness between about 0.3 mm and about 3 mm, between about 0.5 mm and about 2 mm, or between about 0.5 mm and about 1.5 mm.
  • the width of the separation channel can be between about 0.2 mm and about 1.5 mm, between about 0.25 mm and about 1 mm, or between about 0.25 mm and about 0.75 mm.
  • the depth (or height) of the separation channels 302 can be between about 0.05 mm and about 1 mm, between about 0.2 mm and about 0.8 mm, or between about 0.2 mm and about 0.5 mm.
  • the wall thickness of the separation channels 302 can be between about 0.25 mm and about 2 mm, between about 0.5 mm and about 1.5 mm, or between about 1 mm and about 1.5 mm.
  • the floor thickness of the separation channels 302 can be between about 0.2 mm and about 2 mm, between about 0.75 mm and about 1.75 mm, or between about 1 mm and about 1.25 mm.
  • the roof thickness of the separation channels 302 can be between about 0.2 mm and about 2 mm, between about 0.75 mm and about 1.75 mm, or between about 1 mm and about 1.25 mm.
  • the length of the separation channels 302 can be between about 10 mm and about 200 mm, between about 20 mm and about 150 mm, or between about 30 mm and about 100 mm.
  • the flow rate through each of the separation channels can be between about 0.01 ml/min and about 1 ml/min, between about 0.1 ml/min and about 0.5 ml/min, or between about 0.1 ml/min and about 0.25 ml/min.
  • the isolation slots 306 can have a width between about 0.05 mm and about 1.5 mm, between about 0.25 mm and about 1.5 mm, or between about 0.5 mm and about 1.25 mm.
  • the base substrate 308 of the microfluidic flow chamber 300 is an acoustically inactive substrate.
  • the base substrate 308 does not substantially transmit waves generated by the acoustic transducers 208.
  • the acoustic transducers 208 and the heat sinks 312 are coupled to the base substrate 308.
  • the base substrate 308 can also include electrical traces for powering the acoustic transducers 208.
  • the base substrate 308, with its associated acoustic transducers 208 and heat sinks 312 is reusable and the microfluidic flow chamber 300 is disposable.
  • a material of high thermal conductivity can be positioned between the acoustic transducers 208 and the base substrate 308. This material may be "heat sink compound", a thermally conducting grease, glycerol, graphite, or compressible sheets known as "gap pads" in the electronics industry.
  • each acoustic transducers 208 applies a standing wave 314 to the separation channel 302 to the right of the acoustic transducer 208.
  • the standing wave 314 travels from the acoustic transducer 208, through the portion of the substrate 304 defining the left wall of the separation channel 302, into the separation channel 302, and then into the portion of the substrate 304 defining the right wall of the separation channel 302.
  • the isolation slots 306 substantially fail to transmit the standing wave 314, which prevents the standing wave 314 from
  • the microfluidic flow chamber 300 can be coupled to the base substrate 308 by glue or by mechanically coupling the microfluidic flow chamber 300 to the base substrate 308.
  • the microfluidic flow chamber 300 can be clamped to the base substrate 308.
  • the base substrate 308 and the microfluidic flow chamber 300 include registration features that help properly position the substrate 304 on the base substrate 308.
  • the microfluidic flow chamber 300 can be coupled to acoustic transducers 208 (or transducer) in a manner to substantially preserve uniform acoustic energy in each of the separation channels.
  • the microfluidic flow chamber 300 can be coupled with the transducers 208 using an ultraviolet (UV) activated epoxy.
  • UV epoxy can enable accurate setup and positioning of the microfluidic flow chamber 300 in relation to the acoustic transducer before the UV epoxy is cured with UV light.
  • the heat sinks 312 of the microfluidic flow chamber 300 are configured to dissipate heat generated by the acoustic transducers 208.
  • the heat sinks 312 are configured to dissipate enough heat to prevent the acoustic transducers 208 from warming fluids flowing through the separation channels 302.
  • the heat sinks 312 are, or include, thermoelectric coolers.
  • the base substrate 308 includes fluidic lines that flow into the heat sinks 312 to provide fluidic cooling to the heat sinks 312.
  • FIGS. 18 and 19 illustrate cross-sectional views of example microfluidic flow chambers.
  • FIG. 18 illustrates a cross-sectional view of an example microfluidic flow chamber 400 with symmetrical walls
  • FIG. 19 illustrates a cross-sectional view of an example microfluidic flow chamber 450 with asymmetrical walls.
  • asymmetrical walls refer to opposite walls of the separation channels having different thicknesses.
  • FIG. 18 illustrates a single separation channel 401, which may be one of an array of separation channels, as described above in relation to FIG. 13.
  • the separation channel 401 is defined by a cover sheet 402 sitting atop a channel layer 403.
  • the cover sheet 402 is coupled to the channel layer 403, which is coupled to a base substrate 404.
  • an acoustic transducer 208 is coupled to an inner wall of a isolation slot and applies a standing wave 405 to the separation channel 401.
  • the channel layer 403 and cover sheet 402 of the separation channel 401 are manufactured from, and without limitation, polystyrene, glass and polyimide, polyacrylic, polysulfone, silicon, polystyrene, acrylic (polymethylmethacrylate ), or other materials.
  • the channel layer 403 is manufactured by milling, embossing, and/or etching. After creating the two layers, the two layers are joined together by
  • the acoustic transducer 208 imparts the standing wave 405 at a specific wavelength ( ⁇ ) across the separation channel 401.
  • the dimensions of the channel layer 403, cover sheet 402, and separation channel 401 are dependent on the selected wavelength ( ⁇ ), as described below.
  • the substrate sheet is relatively elastic (e.g., when a polystyrene or acrylic material is used), which provides a relatively lower acoustic contrast between the fluid flowing through the separation channel 401 and the walls of the channel layer 403.
  • the relatively elastic materials can form a poor resonator.
  • the channel width can be defined using design rules and dimension ratios (with respect to the wall thickness, wave speed in the fluid and plastic, and/or the operating frequency) specific to plastics.
  • the channel width can be defined by a ratio of width of channel to width of wall, expressed as: w s n c s
  • Cf denotes acoustic velocity in the fluid flowing through the channel
  • c s denotes acoustic velocity in the wall material
  • the wall width is w s
  • w/ denotes the channel width
  • the thickness of the side wall is equal to c wa i ⁇ f, where c wa ii is the speed of sound in the wall material.
  • the c wa ii for the material is equal to the bulk longitudinal velocity of sound through the material c p .
  • odd multiples of the calculated wall thickness may be used.
  • the width of the separation channel 401 is equal to about half the wavelength of the standing wave 405 in the fluid ( ⁇ ⁇ /2).
  • the bulk longitudinal velocity of sound through the material c ⁇ is greater than the speed of sound through the fluid Cfl uid , which is greater than speed of the reflected wave c s .
  • the acoustic impedance mismatch between the shear wave and the longitudinal wave is small, which enables the standing wave 405 to be transferred from the channel layer 403 to the separation channel 401 with minimal loss of energy.
  • the substrate is formed from silicon and the separation channel is filled with water.
  • the speed of sound in water is about 1460 m/s and the acoustic transducer 208 is operated at about 1.7 MHz
  • the width of the separation channel would be about 0.4 mm and the wall thickness (based on a speed of sound in silicon of about 5968 m/s) would be 0.88 mm.
  • the separation channel When using a weak resonator material, such as polystyrene, the separation channel would be about 0.4 mm, but the wall thickness would be about 1.05 mm (based on a speed of sound in polystyrene of about 1120 m/s) and the transducer 208 is operated at about 1.0 MHz.
  • a weak resonator material such as polystyrene
  • FIG. 19 illustrates a single separation channel 451, which may be one of an array of separation channels, as described above in relation to FIG. 13.
  • the separation channel 451 is defined by a cover sheet 452 sitting atop a channel layer 453.
  • the cover sheet 452 is coupled to the channel layer 453, which is coupled to a base substrate 404.
  • an acoustic transducer 208 is coupled to an inner wall of an isolation slot and applies a standing wave 405 to the separation channel 451.
  • the separation channel 451 is formed off-center with respect to the channel layer 453, which forms asymmetrically thick walls on either side of the separation channel 451.
  • the thicker wall is adjacent to the acoustic transducer 208.
  • the thinner wall can be adjacent to the acoustic transducer 208.
  • a microfluidic flow chamber with asymmetrical walls is formed in a substrate that has a relatively low acoustic impedance compared to the fluid flowing through the separation channels because it is important that the wave transfer between the wall material and fluid with relatively little energy loss.
  • the substrate is relatively more elastic (e.g., includes polystyrene or acrylic) than compared to silicon, glass, or a metal.
  • forming the microfluidic flow chamber 450 with asymmetrical walls enables the capture particles to be focused along an arbitrary axis of the separation channel 451. This is in contrast to implementations with symmetrical walls where the capture particles can be aligned with an axis in the center of the separation channel 401 or along the walls of the separation channel 401.
  • the channel 451 dimensions and channel layer 453 width are calculated as described above with respect to the device with symmetrical walls, but one of the sidewalls is thicker than the other by a length equal to 1 ⁇ 4 of the width of channel 451.
  • the thicknesses of each of the walls is determined through numerical simulation.
  • the thicker wall has a thickness of about c w /4/ + d
  • the thinner wall has a thickness of about Cw/4 - d.
  • the lateral width of the separation channel is about Cf/2/
  • Cf is the acoustic velocity of an acoustic wave in the wall material (or an odd multiple thereof)
  • Cf is the acoustic velocity of the acoustic wave in the fluid,/is the desired operating frequency of the acoustic wave, and dis a width increment defined by Cf/16/ ⁇ d ⁇ Cf/4/
  • / is multiplied by a factor of between about 1.5 and about 2.5, between about 1.5 and about 2, or about 1.7.
  • FIG. 20 illustrates a top view of an example separation channel 500 and a cross- sectional view of the separation channel 500 made along cut line A-A.
  • the separation channel 500 includes asymmetrical walls, where wall 501 is thicker than wall 502.
  • the separation channel 500 includes an inlet 508, a first outlet 503 and a second outlet 504.
  • a plurality of capture particles 505 flow down the separation channel 500 in a direction 509 from the inlet 508 to the first and second outlets 503 and 504.
  • a standing wave 506 is applied to the separation channel 500 forming an aggregation axis 507.
  • the above described devices that include arrays of separation channels can include arrays of separation channels with asymmetrical walls.
  • the capture particles 505 align at the aggregation axis 507.
  • the aggregation axis 507 can be formed at a pressure node or pressure antinode of the standing wave 506.
  • devices with symmetrical walls include three outlets to collect the separated contents of a fluid.
  • a device with symmetrical walls may align the capture particle toward the center of the separation channel.
  • a capture particle dense fluid would then flow into a central outlet of the device, and a capture particle depleted fluid would slow into the two lateral outlets.
  • a device with asymmetrical walls can be less complex because the separation channels can include only two outlets.
  • the aggregation axis 507 is created between the central axis of the separation channel's lumen and the face of the wall 501 of the separation channel 500. As illustrated in FIG. 20, the aggregation axis 507 is generated toward the wall 501; however, the thicknesses of the walls 501 and 502 can be adjusted to place the aggregation axis 507 at any location in the separation channel 500.
  • the capture particle dense fluid can be collected with a first outlet 503 and the capture particle depleted fluid is collected with the second outlet 504.
  • the first outlet 503 and the second outlet 504 are substantially the same size. In other implementations, the first outlet 503 and the second outlet 504 are sized differently.
  • the aggregation axis 507 can be placed closer to the wall 501, enabling the first outlet 503 to be smaller than the second outlet 504.
  • FIG. 21 illustrates a flow chart of an example method 600 of cleansing a fluid.
  • the method 600 includes providing a fluid cleansing device (step 602).
  • a fluid containing capture particles is flowed through the fluid cleansing device (step 604).
  • the capture particles are directed toward a first aggregation axis in each of the separation channels of the fluid cleansing device (step 606).
  • the method 600 includes providing a fluid cleansing device (step 602).
  • the fluid cleansing device can include any of the microfluidic flow chambers described herein.
  • the fluid cleansing device includes substrate 201 that defines an array of separation channels 202.
  • Each of separation channels 202 includes an inlet 203 at an upstream portion and two or more outlets 204 at a downstream portion of the separation channel 202.
  • Each of the adjacent separation channels 202 are separated from one another by an isolation slot 207.
  • An acoustic transducer 208 is positioned within each of the isolation slots 207 and directs a standing acoustic wave toward a different one of the separation channels 202.
  • the method 600 also includes flowing a fluid through the fluid cleansing device (step 604).
  • capture particles are mixed into the fluid before the fluid flows through the fluid cleansing device.
  • the capture particles are configured to be acoustically mobile in the presence of a standing wave (e.g., the standing wave drives the capture particles to pressure node or pressure antinode).
  • the acoustic mobility of the capture particles is tuned by configuring the capture particles to have a specific size, density, or compressibility.
  • the capture particles are configured to be substantially more or substantially less acoustically mobile than other particles in the fluid.
  • the capture particles include affinity particles anchored to the outer surface of the capture particles.
  • the affinity particles are configured to bind to toxins, proinflammatory cytokines, bacteria, viruses, or specific cell types.
  • cells such as red blood cells, are acoustically mobile and may be driven to an aggregation axis without the use of capture particles.
  • the method 600 also includes directing the capture particles toward a first aggregation axis in each of the separation channels of the fluid cleansing device (step 606).
  • each of the acoustic transducers 208 generate a standing acoustic wave within a respective separation channel.
  • the standing waves forms pressure nodes and/or pressure antinodes within the separation channel, which form aggregation axis along the length of the separation channel.
  • the capture particles are directed toward the aggregation axis 507 by the standing wave 506.
  • the aggregation axis 507 is aligned with the first outlet 503.
  • the capture particles 505 align with the aggregation axis 507 and flow out the first outlet 503. Simultaneously, capture particles depleted fluid flows out the second outlet 504.
  • the capture particles include affinity particles that bind to a toxin
  • the capture particles can be mixed with a patient's blood.
  • the capture particles will bind to the toxin in the patient's blood.
  • the capture particles As the capture particles flow down the separation channel, the capture particles, with their bound toxins, exit the fluid cleansing device at outlet 503. Blood substantially free of toxin exits the fluid cleansing device at outlet 504 and can be returned to the patient.
  • the capture particles exiting the outlet 503 can be further processed to separate the capture particles (and toxins) from the blood flowing out the first outlet 503.
  • FIG. 22 illustrates a flow chart of an example method 650 for cleansing a fluid.
  • the method 600 includes providing a fluid cleansing device (step 652). A fluid is flowed through the fluid cleansing device (step 654). Particles within the blood are directed toward a first aggregation axis in each of the separation channels of the fluid cleansing device (step 656).
  • the method 600 includes providing a fluid cleansing device (step 652).
  • the fluid cleansing device can include any of the microfluidic flow chambers described herein.
  • the fluid cleansing device includes substrate 201 that defines an array of separation channels 202.
  • Each of separation channels 202 includes an inlet 203 at an upstream portion and two or more outlets 204 at a downstream portion of the separation channel 202.
  • Each of the adjacent separation channels 202 are separated from one another by an isolation slot 207.
  • An acoustic transducer 208 is positioned within each of the isolation slots 207 and directs a standing acoustic wave toward a different one of the separation channels 202.
  • the method 650 also includes flowing a fluid through the fluid cleansing device (step 654).
  • the fluid can be blood.
  • Some particles within the fluid such as red blood cells, cells, or other elements within the fluid, can be acoustically mobile in the presence of a standing wave (e.g., the standing wave drives the particles to pressure node or pressure antinode).
  • the method 650 also includes directing the particles of the fluid toward a first aggregation axis in each of the separation channels of the fluid cleansing device (step 656). Also with reference to FIGS. 13-20 and 3-templ 1, each of the acoustic transducers 208 generate a standing acoustic wave within a respective separation channel. The standing waves forms pressure nodes and/or pressure antinodes within the separation channel, which form aggregation axis along the length of the separation channel. As illustrated in FIG. 20, the particles in the fluid (e.g., red blood cells) are directed toward the aggregation axis 507 by the standing wave 506. The aggregation axis 507 is aligned with the first outlet 503. As the fluid travels down the separation channel, the particles align with the aggregation axis 507 and flow out the first outlet 503. Simultaneously, particles depleted fluid (e.g., fluid without red blood cells) flows out the second outlet 504.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Analytical Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Hematology (AREA)
  • Clinical Laboratory Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Automatic Analysis And Handling Materials Therefor (AREA)

Abstract

L'invention concerne un système et un procédé de séparation microfluidique. Plus particulièrement, l'invention concerne un système et un procédé pour la purification d'un fluide par élimination de particules indésirables. Le dispositif comprend des canaux de séparation microfluidiques qui comprennent de multiples sorties. Le dispositif comprend également des fentes d'isolation positionnées entre chacun des canaux de séparation microfluidique. La base du dispositif comprend de multiples transducteurs acoustiques qui, dans certains modes de réalisation, sont configurés pour faire saillie dans les fentes d'isolation. Les transducteurs acoustiques sont configurés pour générer des axes d'agrégation à l'intérieur des canaux de séparation, qui sont utilisés pour séparer des particules indésirables.
EP18724667.3A 2017-04-25 2018-04-25 Systèmes et procédés de séparation microfluidique de canal parallèle Pending EP3600667A1 (fr)

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PCT/US2018/029328 WO2018200652A1 (fr) 2017-04-25 2018-04-25 Systèmes et procédés de séparation microfluidique de canal parallèle

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US11618022B2 (en) * 2019-04-04 2023-04-04 The Charles Stark Draper Laboratory, Inc. Microfluidic acoustic separation devices
EP4164795A4 (fr) * 2020-06-12 2024-01-24 BioFluidica, Inc. Dispositif microfluidique thermoplastique à double profondeur et systèmes et procédés associés
WO2024064921A1 (fr) * 2022-09-22 2024-03-28 Astrin Biosciences, Inc. Équilibrage de pression à travers des dispositifs microfluidiques

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WO1998046986A1 (fr) * 1997-04-15 1998-10-22 Sarnoff Corporation Procede de translocation de microparticules dans un dispositif microfabrique
US20040109793A1 (en) * 2002-02-07 2004-06-10 Mcneely Michael R Three-dimensional microfluidics incorporating passive fluid control structures
US6814859B2 (en) * 2002-02-13 2004-11-09 Nanostream, Inc. Frit material and bonding method for microfluidic separation devices
JP2008539090A (ja) * 2005-04-26 2008-11-13 アビザ テクノロジー リミティド マイクロ流体構造およびその製造方法
US10099002B2 (en) * 2014-07-31 2018-10-16 The Charles Stark Draper Laboratory, Inc. Systems and methods for parallel channel microfluidic separation

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