Magnetic particle isolation devices and methods of use

Abstract

To provide favorable magnetic particle isolation devices and methods of use.SOLUTION: The present invention provides devices and methods of isolating particles. A fluidics particle isolation device is disclosed having a fluidic channel extending therethrough, where a segment of the fluidic channel is exposed to an asymmetric magnetic field such that, when a solution containing the particles in a paramagnetic medium are passed through the magnetic field, the particles are isolated within the solution.SELECTED DRAWING: Figure 23

Description

[Technical Field]

[0001] (cross reference) This application claims the benefit of U.S. Provisional Application No. 62 / 648,300, filed March 26, 2018, and U.S. Provisional Application No. 62 / 728,684, filed September 7, 2018, which are incorporated herein by reference in their entireties.

[0002] The present invention relates generally to the magnetic levitation of particles, such as cells or biomolecules, in a medium in order to isolate such particles. [Background technology]

[0003] Isolation of particles contained within a medium is a critical step in many chemical and biological processes. In some processes, there may be a need to simply isolate particles to facilitate their use or manipulation, while in other processes there may be a need to separate particles from other particles also present in the medium. Devices may rely on the magnetic properties of the particles and their surrounding medium to separate particles of interest from a heterogeneous population of particles.

[0004] For example, a levitation system can have a microcapillary channel positioned between two sets of magnets. A heterogeneous population of cells in a magnetically responsive medium can be sent through the microcapillary channel and exposed to a magnetic field generated by two adjacent magnets. In response to exposure to the magnetic field, cells of the same type within the heterogeneous population of cells can levitate to a specific height within the microcapillary channel, thereby separating the cells from each other. The levitation height of a given cell can be determined based on the balance of magnetic forces and compensated gravity on the individual cells.

[0005] The two magnets can be positioned symmetrically with respect to the capillary channel so that the magnetic field strength distribution is symmetric with respect to each axis of the capillary channel. In some cases, the symmetric configuration of the magnets can limit the device's ability to separate particles. In some cases, using a vertically symmetric configuration of the magnets can allow all particles in the magnetically responsive medium, which is denser than the medium itself, to levitate to a position below the axis of symmetry (i.e., the vertical midpoint between the two magnets). This can have two consequences: (1) the extent of levitation height can be constrained to half the available space between the magnets; and (2) the fluid path can be trapped within a smaller space (i.e., the lower half of the channel), which can cause processing difficulties and increase flow resistance. Moving the magnets further apart and using a larger capillary can result in a shallower magnetic field gradient, which, all other factors being equal, can result in a weaker separation force on the particles.

[0006] Therefore, there is a need for a cell isolation device that improves selectivity by increasing the spread of levitation locations for a given surface strength of the magnet, and improves the manufacturability and operability of fluidic devices coupled to the levitation region. Summary of the Invention [Means for solving the problem]

[0007] The embodiments of the invention provided in this Summary are illustrative only and are intended to provide an overview of selected embodiments disclosed herein. Being illustrative and selective, this Summary does not limit the scope of any claims, does not provide the entire scope of embodiments of the invention disclosed or contemplated herein, and should not be construed as limiting or restricting the scope of the present disclosure or any claimed embodiments of the invention.

[0008] Provided herein is a particle isolation device that includes a fluid channel and two magnetic components positioned on opposite sides of the fluid channel along a substantially vertical axis, the two magnetic components configured to generate an asymmetric magnetic field within the fluid channel.

[0009] Also provided herein is a particle isolation device having a fluidic channel structure, at least two magnetic components, and one or more pumps configured to drive a fluid from an input port through the fluidic channel structure and out of an output port. According to this embodiment, the fluidic channel structure includes at least one input port and at least one output port interconnected by a fluidic channel, and the fluidic channel includes a substantially linear portion including a leading end in fluid communication with the input port and a trailing end in fluid communication with the output port. This embodiment further includes two magnetic components positioned substantially perpendicular to and on opposite sides of the substantially linear portion of the fluidic channel, the two magnetic components configured to generate an asymmetric magnetic field within the substantially linear portion of the fluidic channel.

[0010] Also provided herein is a particle isolation device comprising a fluidic channel structure having at least one input port and at least two output ports interconnected by a series of fluidic channels, the series of fluidic channels including first, second, and third generally linear portions. According to this embodiment, the fluidic channel structure includes a first processing path and a second processing path. The first processing path extends from the input port to the first generally linear portion, from the first generally linear portion to the second generally linear portion, and from the second generally linear portion to the output port. The second processing path extends from the input port to the first generally linear portion, from the first generally linear portion to the third generally linear portion, and from the third generally linear portion to the output port. The device further includes first, second, and third pairs of magnetic components positioned generally perpendicular to opposite sides of the first, second, and third generally linear portions of the fluid channel, respectively, at least one of the pair of magnetic components configured to generate an asymmetric magnetic field within its adjacent generally linear portion of the fluid channel. The device further includes one or more pumps configured to drive fluid from the at least one input port through the fluid channel and out of the at least one output port.

[0011] In one aspect, the magnetic component of the particle isolation device generates a magnetic field within the fluid channel that is asymmetric, preferably asymmetric along a substantially vertical axis.

[0012] In another aspect, a particle isolation device includes two magnetic components configured with respect to a fluid channel such that a first of the two magnetic components generates a magnetic field in the fluid channel that is stronger than a magnetic field in the fluid channel generated by a second of the two magnetic components.

[0013] In another aspect, the particle isolation device includes two magnetic components that are permanent magnets or electromagnets. The magnetic components may comprise permanent bar magnets including neodymium-iron, samarium-cobalt, aluminum-iron-cobalt alloys, or ferrite.

[0014] In another aspect, the particle isolation device includes two magnetic components including an upper magnet and a lower magnet, wherein the upper magnet is larger than the lower magnet, or the lower magnet is larger than the upper magnet.

[0015] In another aspect, the particle isolation device includes a splitter that partitions the fluid channel into at least two channels. In some embodiments, the splitter is positioned within the fluid channel at an end of a substantially linear portion of the fluid channel and divides the fluid channel into two or more channels. In some embodiments, the splitter is positioned within the fluid channel such that the fluid channel splits at a location between two magnetic components. In some embodiments, the splitter partitions the fluid channel into a plurality of vertically spaced compartments.

[0016] In a further aspect, the particle isolation device comprises an integrated fluidic chip or cartridge.

[0017] In another aspect, the particle isolation device includes one or more valves for controlling fluid flow within the fluid channel and / or fluid flow into or out of the at least one output port.

[0018] In another aspect, the particle isolation device includes a device for visualizing and / or recording images of the particles as they pass through the asymmetric magnetic field.

[0019] Further provided herein is a particle isolation device comprising one or more processing compartments, each processing compartment comprising a substantially linear fluid channel portion flanked on either side by a pair of magnetic components, whereby the processing compartments are in fluid communication with each other in parallel or in series.

[0020] In one aspect of the invention, a particle isolation device includes a fluidic channel structure having a plurality of substantially linear portions, wherein a first pair of magnetic components is configured to generate a symmetric magnetic field within the fluidic channel of the first substantially linear portion, a second pair of magnetic components is configured to generate an asymmetric magnetic field within the fluidic channel of the second substantially linear portion, and a third pair of magnetic components is configured to generate an asymmetric magnetic field within the fluidic channel of the third substantially linear portion. According to one embodiment, the first substantially linear portion is in serial fluid communication with the second and third substantially linear portions, and the second and third substantially linear portions are configured in parallel and are not in direct fluid communication.

[0021] In one aspect, a first pair of magnetic components includes a first upper bar magnet positioned above the first linear portion and a first lower bar magnet positioned below the first generally linear portion, the first upper magnet and the first lower magnet being positioned in a magnetically repelling orientation; a second pair of magnetic components includes a second upper bar magnet positioned above the second generally linear portion and a second lower bar magnet positioned below the second generally linear portion, the second upper magnet and the second lower magnet being positioned in a magnetically repelling orientation; and a third pair of magnetic components includes a third upper bar magnet positioned above the third generally linear portion and a third lower bar magnet positioned below the third generally linear portion, the third upper magnet and the third lower magnet being positioned in a magnetically repelling orientation. In a further aspect, the second upper bar magnet emits a stronger magnetic field than the second lower bar magnet, and the third lower bar magnet emits a stronger magnetic field than the third upper bar magnet. In a further aspect, the second upper bar magnet comprises two or more magnets that emit a stronger magnetic field than the second lower bar magnet, and the third lower bar magnet comprises two or more magnets that emit a stronger magnetic field than the third upper bar magnet.

[0022] In another aspect, a particle isolation device comprises one or more sets of parallel fluid channels sharing one or more central or scattered magnets, the magnets positioned to shape a magnetic field within each separate fluid channel, with opposing magnets for each separate fluid channel positioned with like poles facing (i.e., SS or NN).

[0023] In another aspect, a particle isolation device comprises a set of one or more wells for performing static separation in an assay format, wherein adjacent wells may share one or more magnets, e.g., stacked magnets, to generate a magnetic field, e.g., a shaped magnetic field, that isolates particles within the medium, e.g., within the center of the medium.

[0024] In another aspect, the particle isolation device further includes a first splitter starting along an end of the fluid channel in the first generally linear portion, a second splitter starting along an end of the fluid channel in the second generally linear portion, and a third splitter starting along an end of the fluid channel in the third generally linear portion. In a further aspect, the first splitter splits the fluid channel along the first generally linear portion into at least two fluid channels, whereby one of the at least two fluid channels is in fluid communication with the fluid channel in the second generally linear portion and one of the at least two fluid channels is in fluid communication with the fluid channel in the third generally linear portion. In another aspect, the second splitter splits the fluid channel along the second generally linear portion into at least two fluid channels, whereby the at least two fluid channels are in fluid communication with corresponding outlet ports. In a further aspect, a third splitter divides the fluid channel along the third generally linear portion into at least two fluid channels, whereby the at least two fluid channels are in fluid communication with corresponding outlet ports.

[0025] In one embodiment of the present invention, a method for isolating particles is provided, the method including: (a) forming a processing solution including particles and a paramagnetic medium; (b) passing the processing solution through a particle isolation device, the device including a fluid channel structure including a fluid channel and at least two magnetic components positioned on opposite sides of the fluid channel, the two magnetic components generating an asymmetric magnetic field within the fluid channel, thereby isolating particles as they pass through the asymmetric magnetic field, thereby generating isolated particles; and (c) observing, analyzing, recording, and / or collecting the isolated particles.

[0026] In one aspect, the method of the present invention is practiced using a fluid channel structure including at least one input port and at least one output port interconnected by a fluid channel, the fluid channel including a generally linear portion having a leading end in fluid communication with the input port and a trailing end in fluid communication with the output port, at least two magnetic components positioned generally perpendicular to opposite sides of the generally linear portion of the fluid channel, the at least two magnetic components configured to generate an asymmetric magnetic field within the generally linear portion of the fluid channel, and optionally, one or more pumps configured to drive fluid from the at least one input port, through the fluid channel, and out through the at least one output port, the method further including pumping a processing solution through the fluid channel, and observing, analyzing, and / or recording the isolated particles including observing, analyzing, and / or recording the isolated particles along the generally linear portion of the fluid channel and / or collecting the isolated particles from the at least one output port.

[0027] In a further aspect, the paramagnetic medium comprises a paramagnetic material and a solvent. In another aspect, the paramagnetic medium comprises a paramagnetic material, salts, and other additives that function to maintain cellular integrity. In another aspect, the paramagnetic medium is biocompatible.

[0028] In a further aspect, the paramagnetic material may include gadolinium, titanium, vanadium, chromium, manganese, iron, nickel, gallium, dysprosium, ions thereof, or combinations thereof. In a further aspect, the paramagnetic material includes titanium(III) ions, gadolinium(III) ions, vanadium(I) ions, nickel(II) ions, chromium(III) ions, dysprosium(III) ions, vanadium(III) ions, cobalt(II) ions, or gallium(III) ions. In a further aspect, the paramagnetic material includes a chelate compound. In a further aspect, the paramagnetic material includes a gadolinium chelate, a dysprosium chelate, or a manganese chelate.

[0029] In another aspect, the paramagnetic material is present in the paramagnetic medium at a concentration of at least 10 mM, 20 mM, 30 mM, 40 mM, 50 mM, 60 mM, 70 mM, 80 mM, 90 mM, 100 mM, 120 mM, 150 mM, 200 mM, 250 mM, 300 mM, 500 mM, or 1M. In further aspects, the paramagnetic material is present in the paramagnetic medium at a concentration of about 10 mM to about 50 mM, about 25 mM to about 75 mM, about 50 mM to about 100 mM, about 100 mM to about 150 mM, about 150 mM to about 200 mM, about 200 mM to about 250 mM, about 250 mM to about 300 mM, about 300 mM to about 500 mM, or about 500 mM to about 1 M.

[0030] In another aspect, the paramagnetic material comprises gadolinium and is present in the paramagnetic medium at a concentration of at least about 10 mM, 20 mM, 30 mM, 40 mM, 50 mM, 60 mM, 70 mM, 80 mM, 90 mM, or 100 mM. In a further aspect, the paramagnetic material comprises gadolinium and is present in the paramagnetic medium at a concentration of about 10 mM to about 50 mM, about 25 mM to about 75 mM, or about 50 mM to about 100 mM.

[0031] In another aspect, the at least two magnetic components include an upper magnet and a lower magnet, wherein the density of the particles is greater than the density of the paramagnetic material and the magnetic field generated by the lower magnet is greater than the magnetic field generated by the upper magnet, hi another aspect, the density of the particles is less than the density of the paramagnetic material and the magnetic field generated by the lower magnet is less than the magnetic field generated by the upper magnet.

[0032] In another aspect, as the processing solution passes through the asymmetric magnetic field, the particles of interest will reach substantially similar equilibrium altitudes. In a further aspect, the at least two magnetic components comprise an upper magnet and a lower magnet, wherein substantially all of the particles contained within the treatment solution reach an equilibrium altitude, and the difference between the highest equilibrium altitude of the particles and the lowest equilibrium altitude of the particles (i.e., the equilibrium altitude distribution) is equal to less than 35% of the vertical gap between the upper and lower magnets, or less than 30% of the vertical gap between the upper and lower magnets, or less than 25% of the vertical gap between the upper and lower magnets, or less than 20% of the vertical gap between the upper and lower magnets, or less than 15% of the vertical gap between the upper and lower magnets, or less than 10% of the vertical gap between the upper and lower magnets, or less than 8% of the vertical gap between the upper and lower magnets, or less than 6% of the vertical gap between the upper and lower magnets, or less than 5% of the vertical gap between the upper and lower magnets. In one aspect, the equilibrium height distribution of substantially all of the particles of interest is less than about 5,000 microns, less than 4,000 microns, less than 3,000 microns, less than 2,000 microns, less than 1,000 microns, less than 500 microns, less than 300 microns, or less than 200 microns, or the equilibrium height distribution of substantially all of the particles of interest is between about 1 micron and about 5,000 microns, or between about 1 micron and about 3,000 microns, or between about 1 micron and about 1,000 microns, or between about 1 micron and about 500 microns, or between about 1 micron and about 200 microns.

[0033] According to the methods of the present invention, once substantially all of the particles reach an equilibrium altitude, the particles are passed through a splitter that geometrically divides the treatment solution into multiple effluent fractions, and one or more effluent fractions containing substantially all of the particles are collected, thereby isolating the particles. In certain aspects of the present invention, substantially all of the particles comprise at least about 70%, 75%, 80%, 85%, 90%, or 95% of the particles.

[0034] In another aspect, the method further comprises separating the isolated particle from the paramagnetic medium. In another aspect, the particle comprises a biomolecule, a cell, a group of cells, a protein, a lipid, a carbohydrate, a microorganism, or a bacterium.

[0035] According to an embodiment, a method for isolating particles is provided, comprising: (a) forming a processing solution containing particles and a paramagnetic medium; (b) passing the processing solution through a particle isolation device, the device comprising a fluid channel structure including a series of fluid channels and at least two processing compartments, each of the at least two processing compartments including at least two magnetic components positioned on opposite sides of a portion of the fluid channel, the two magnetic components generating asymmetric magnetic fields within their corresponding portions of the fluid channel, whereby a portion of the processing solution passes through the at least two processing compartments in parallel, and / or a portion or all of the processing solution passes through the at least two processing compartments in series, thereby isolating particles as they pass through the asymmetric magnetic fields of the processing compartments; and (c) observing, analyzing, recording, and / or collecting the isolated particles.

[0036] In one aspect, the method of the present invention includes a fluid channel structure including at least one input port and at least two output ports interconnected by a series of fluid channels, the series of fluid channels including a first generally linear portion, a second generally linear portion, and a third generally linear portion, the fluid channel structure including: (i) a first processing path extending from the at least one input port to the first generally linear portion, and from the first generally linear portion to the second generally linear portion, and from the second generally linear portion to an output port of the at least two output ports; and (ii) a second processing path extending from the at least one input port to the first generally linear portion, and from the first generally linear portion to the third generally linear portion, and from the third generally linear portion to an output port of the at least two output ports, the second generally linear portion being inversely related to the first generally linear portion, the second generally linear portion, and the third generally linear portion, respectively. a first pair of magnetic components, a second pair of magnetic components, and a third pair of magnetic components positioned generally perpendicular to opposite sides, wherein at least one of the first pair of magnetic components, the second pair of magnetic components, or the third pair of magnetic components is configured to generate an asymmetric magnetic field within its adjacent generally linear portion; and one or more pumps are configured to drive fluid from at least one input port through a series of fluid channels and out through at least two output ports, the method including passing a portion of the processing solution through a first processing path and passing a portion of the processing solution through a second processing path, whereby a first isolation of the particles exists as the particles pass through the asymmetric magnetic field within the first generally linear portion, and a second isolation of the particles exists as they pass through the asymmetric magnetic field of either the second or third generally linear portion. The present specification also provides, for example, the following items: (Item 1) A particle isolation device comprising a fluid channel and two magnetic components positioned on opposite sides of the fluid channel along a substantially vertical axis, the two magnetic components being configured to generate an asymmetric magnetic field within the fluid channel. (Item 2) Item 10. The particle isolation device of item 1, wherein the magnetic field is asymmetric along a substantially vertical axis. (Item 3) 2. The particle isolation device of claim 1, wherein the two magnetic components are configured with respect to the fluid channel such that a first of the two magnetic components generates a magnetic field in the fluid channel that is stronger than a magnetic field in the fluid channel generated by a second of the two magnetic components. (Item 4) Item 10. The particle isolation device of item 1, wherein the fluid channel includes a substantially linear portion and the two magnetic components are positioned along the substantially linear portion. (Item 5) 1. A particle isolation device comprising: a) a fluid channel structure comprising at least one input port and at least one output port interconnected by a fluid channel, the fluid channel including a substantially linear portion, the substantially linear portion having a leading end in fluid communication with the at least one input port and a trailing end in fluid communication with the at least one output port; b) two magnetic components positioned generally perpendicular to opposite sides of the generally linear portion of the fluid channel, the two magnetic components configured to generate an asymmetric magnetic field within the generally linear portion of the fluid channel; and c) optionally, one or more pumps configured to drive fluid from said at least one input port through said fluid channel and out said at least one output port; A particle isolation device comprising: (Item 6) 6. The particle isolation device of claim 5, wherein the two magnetic components are configured with respect to the fluid channel such that a first of the two magnetic components generates a magnetic field in the fluid channel that is stronger than a magnetic field in the fluid channel generated by a second of the two magnetic components. (Item 7) Item 6. The particle isolation device of item 5, wherein the two magnetic components comprise permanent magnets or electromagnets. (Item 8) Item 6. The particle isolation device of item 5, wherein the two magnetic components comprise permanent bar magnets comprising neodymium-iron, samarium-cobalt, or ferrite. (Item 9) 6. The particle isolation device of claim 5, wherein the two magnetic components comprise an upper magnet and a lower magnet, and the upper magnet is larger than the lower magnet, or the lower magnet is larger than the upper magnet. (Item 10) Item 6. The particle isolation device of item 5, wherein an end of the substantially linear portion of the fluid channel comprises a splitter that divides the fluid channel into at least two channels. (Item 11) Item 11. The particle isolation device of item 10, wherein the splitter is positioned within the fluid channel such that the fluid channel splits at a position between the two magnetic components. (Item 12) Item 11. The particle isolation device of item 10, wherein the splitter partitions the fluid channel into a plurality of vertically spaced compartments. (Item 13) 6. The particle isolation device of item 5, wherein the at least one input port, the at least one output port, and the fluidic channel are contained within an integrated fluidic chip or cartridge. (Item 14) Item 6. The particle isolation device of item 5, wherein the asymmetric magnetic field is asymmetric along a substantially vertical axis. (Item 15) 6. The particle isolation device of claim 5, wherein the device further comprises one or more valves for controlling fluid flow within the fluid channel and / or from the at least one output port. (Item 16) 6. The particle isolation device of claim 5, further comprising a device for visualizing and / or recording images of the particles as they pass through the asymmetric magnetic field. (Item 17) Item 17. The particle isolation device of item 16, wherein the device further comprises a visualization window configured to allow visualization of a portion of the fluid channel in which the asymmetric magnetic field is generated. (Item 18) 1. A particle isolation device comprising: a) a fluid channel structure comprising at least one input port and at least two output ports interconnected by a series of fluid channels, the series of fluid channels comprising a first fluid channel comprising a first generally linear portion, a second fluid channel comprising a second generally linear portion, and a third fluid channel comprising a third generally linear portion, the fluid channel structure comprising: a first processing path extending from the at least one input port to the first generally linear portion, extending from the first generally linear portion to the second generally linear portion, and extending from the second generally linear portion to a first output port of the at least two output ports; and a second processing path extending from the at least one input port to the first generally linear portion, extending from the first generally linear portion to the third generally linear portion, and extending from the third generally linear portion to a second output port of the at least two output ports; b) a first pair of magnetic components, a second pair of magnetic components, and a third pair of magnetic components positioned substantially perpendicular to opposite sides of the first substantially linear portion, the second substantially linear portion, and the third substantially linear portion, respectively, wherein at least one of the first pair of magnetic components, the second pair of magnetic components, or the third pair of magnetic components is configured to generate an asymmetric magnetic field within its adjacent substantially linear portion; c) optionally, one or more pumps configured to drive fluid from said at least one input port through said series of fluid channels and out said at least two output ports; A particle isolation device comprising: (Item 19) 20. The particle isolation device of claim 18, further comprising one or more additional processing compartments, each of the one or more additional processing compartments comprising a generally linear fluid channel portion flanked by a pair of magnetic components, whereby the one or more additional processing compartments are in fluid communication with at least one of the first generally linear portion, the second generally linear portion, or the third generally linear portion, and the one or more additional processing compartments are positioned in parallel or in series with at least one of the first generally linear portion, the second generally linear portion, or the third generally linear portion. (Item 20) Item 19. The particle isolation device of item 18, wherein the first pair of magnetic components is configured to generate a symmetric magnetic field along a generally vertical axis in the first generally linear portion, the second pair of magnetic components is configured to generate an asymmetric magnetic field along a generally vertical axis in the second generally linear portion, and the third pair of magnetic components is configured to generate an asymmetric magnetic field along a generally vertical axis in the third generally linear portion. (Item 21) 21. The particle isolation device of claim 20, wherein the first pair of magnetic components comprises a first upper bar magnet positioned above the first generally linear portion and a first lower bar magnet positioned below the first generally linear portion, the first upper magnet and first lower magnet being positioned in a magnetically repulsive orientation; the second pair of magnetic components comprises a second upper bar magnet positioned above the second generally linear portion and a second lower bar magnet positioned below the second generally linear portion, the second upper magnet and second lower magnet being positioned in a magnetically repulsive orientation; and the third pair of magnetic components comprises a third upper bar magnet positioned above the third generally linear portion and a third lower bar magnet positioned below the third generally linear portion, the third upper magnet and third lower magnet being positioned in a magnetically repulsive orientation. (Item 22) 22. The particle isolation device of claim 21, wherein the second upper bar magnet emits a stronger magnetic field than the second lower bar magnet, and the third lower bar magnet emits a stronger magnetic field than the third upper bar magnet. (Item 23) 22. The particle isolation device of claim 21, wherein the second upper bar magnet comprises two or more magnets that emit a stronger magnetic field than the second lower bar magnet, and the third lower bar magnet comprises two or more magnets that emit a stronger magnetic field than the third upper bar magnet. (Item 24) 21. The particle isolation device of claim 20, further comprising: a first splitter starting along an end of the first fluid channel in the first generally linear portion; a second splitter starting along an end of the second fluid channel in the second generally linear portion; and a third splitter starting along an end of the third fluid channel in the third generally linear portion. (Item 25) 25. The particle isolation device of claim 24, wherein the first splitter splits the first fluid channel along the first generally linear portion into at least two fluid channels, whereby a first channel of the at least two fluid channels is in fluid communication with the second fluid channel in the second generally linear portion and a second channel of the at least two fluid channels is in fluid communication with the third fluid channel in the third generally linear portion. (Item 26) 25. The particle isolation device of claim 24, wherein the second splitter divides the second fluid channel along the second generally linear portion into at least two fluid channels, whereby the at least two fluid channels are in fluid communication with corresponding outlet ports. (Item 27) 25. The particle isolation device of claim 24, wherein the third splitter divides the third fluid channel along the third generally linear portion into at least two fluid channels, whereby the at least two fluid channels are in fluid communication with corresponding outlet ports. (Item 28) 1. A method for isolating particles, comprising: a) forming a treatment solution containing particles and a paramagnetic medium; b) passing the processing solution through a particle isolation device, the device comprising a fluid channel structure comprising a fluid channel and at least two magnetic components positioned on opposite sides of the fluid channel, the two magnetic components generating an asymmetric magnetic field within the fluid channel, thereby isolating the particles as they pass through the asymmetric magnetic field, thereby generating isolated particles; c) observing, analyzing, recording, and / or collecting said isolated particles; A method comprising: (Item 29) a) a fluid channel structure comprising at least one input port and at least one output port interconnected by the fluid channel, the fluid channel including a generally linear portion having a leading end in fluid communication with the input port and a trailing end in fluid communication with the output port, the at least two magnetic components positioned generally perpendicular to opposite sides of the generally linear portion of the fluid channel, the at least two magnetic components configured to generate an asymmetric magnetic field within the generally linear portion of the fluid channel; b) optionally, one or more pumps are configured to drive fluid from said at least one input port through said fluid channel and out said at least one output port; c) the method further comprises pumping the processing solution through the fluid channel, and wherein observing, analyzing, and / or recording the isolated particles comprises observing, analyzing, and / or recording the isolated particles along a substantially linear portion of the fluid channel and / or collecting the isolated particles from the at least one output port. (Item 30) 29. The method of claim 28, wherein the paramagnetic medium comprises a paramagnetic material and a solvent. (Item 31) 29. The method of claim 28, wherein the paramagnetic medium comprises a paramagnetic material, salts, and other additives that function to maintain cellular integrity. (Item 32) 29. The method of claim 28, wherein the paramagnetic medium is biocompatible. (Item 33) 31. The method of claim 30, wherein the paramagnetic material comprises gadolinium, titanium, vanadium, chromium, manganese, iron, nickel, gallium, dysprosium, ions thereof, or combinations thereof. (Item 34) 31. The method of claim 30, wherein the paramagnetic material comprises titanium(III) ions, gadolinium(III) ions, vanadium(I) ions, nickel(II) ions, chromium(III) ions, vanadium(III) ions, dysprosium(III) ions, cobalt(II) ions, or gallium(III) ions. (Item 35) 31. The method of claim 30, wherein the paramagnetic material comprises a chelate compound. (Item 36) 31. The method of claim 30, wherein the paramagnetic material comprises a gadolinium chelate, a dysprosium chelate, or a manganese chelate. (Item 37) 31. The method of claim 30, wherein the paramagnetic material is present in the paramagnetic medium at a concentration of at least 10 mM, 20 mM, 30 mM, 40 mM, 50 mM, 60 mM, 70 mM, 80 mM, 90 mM, 100 mM, 120 mM, 150 mM, 200 mM, 250 mM, 300 mM, 500 mM, or 1 M. (Item 38) Item 31. The method according to Item 30, wherein the paramagnetic material is present in the paramagnetic medium at a concentration of about 10 mM to about 50 mM, about 25 mM to about 75 mM, about 50 mM to about 100 mM, about 100 mM to about 150 mM, about 150 mM to about 200 mM, about 200 mM to about 250 mM, about 250 mM to about 300 mM, about 300 mM to about 500 mM, or about 500 mM to about 1 M. (Item 39) 31. The method of claim 30, wherein the paramagnetic material comprises gadolinium and is present in the paramagnetic medium at a concentration of at least 10 mM, 20 mM, 30 mM, 40 mM, 50 mM, 60 mM, 70 mM, 80 mM, 90 mM, or 100 mM. (Item 40) Item 31. The method of item 30, wherein the paramagnetic material comprises gadolinium and is present in the paramagnetic medium at a concentration of about 10 mM to about 50 mM, about 25 mM to about 75 mM, or about 50 mM to about 100 mM. (Item 41) Item 31. The method of item 30, wherein the at least two magnetic components comprise an upper magnet and a lower magnet, the density of the particles is greater than the density of the paramagnetic medium, and the magnetic field generated by the lower magnet is greater than the magnetic field generated by the upper magnet. (Item 42) Item 31. The method of item 30, wherein the at least two magnetic components comprise an upper magnet and a lower magnet, the density of the particles is less than the density of the paramagnetic medium, and the magnetic field generated by the lower magnet is less than the magnetic field generated by the upper magnet. (Item 43) 29. The method of claim 28, wherein the particles reach substantially similar equilibrium altitudes as the processing solution passes through the asymmetric magnetic field. (Item 44) Item 44. The method of item 43, wherein the at least two magnetic components comprise an upper magnet and a lower magnet, wherein substantially all of the particles contained within the processing solution reach an equilibrium altitude, and wherein the difference between the highest equilibrium altitude of the particles and the lowest equilibrium altitude of the particles is equal to less than 35% of the vertical gap between the upper magnet and the lower magnet, or less than 30% of the vertical gap between the upper magnet and the lower magnet, or less than 25% of the vertical gap between the upper magnet and the lower magnet, or less than 20% of the vertical gap between the upper magnet and the lower magnet, or less than 15% of the vertical gap between the upper magnet and the lower magnet, or less than 10% of the vertical gap between the upper magnet and the lower magnet, or less than 8% of the vertical gap between the upper magnet and the lower magnet, or less than 6% of the vertical gap between the upper magnet and the lower magnet, or less than 5% of the vertical gap between the upper magnet and the lower magnet. (Item 45) 45. The method of claim 44, wherein substantially all of the particles have an equilibrium height distribution that is less than about 5,000 microns, less than 4,000 microns, less than 3,000 microns, less than 2,000 microns, less than 1,000 microns, less than 500 microns, less than 300 microns, or less than 200 microns. (Item 46) Item 45. The method of item 44, wherein the equilibrium height distribution of substantially all of the particles is from about 1 micron to about 5,000 microns, or from about 1 micron to about 3,000 microns, or from about 1 micron to about 1,000 microns, or from about 1 micron to about 500 microns, or from about 1 micron to about 200 microns. (Item 47) 47. The method of claim 45 or 46, wherein substantially all of the particles comprise at least 70%, 75%, 80%, 85%, 90%, or 95% of the particles. (Item 48) 29. The method of claim 28, wherein once substantially all of the particles reach an equilibrium altitude, the particles are passed through a splitter that geometrically divides the processing solution into a plurality of effluent fractions, and one or more of the plurality of effluent fractions that contain substantially all of the particles are collected, thereby isolating the particles. (Item 49) 49. The method of claim 44, 45, or 48, wherein substantially all of the particles comprise at least 70%, 75%, 80%, 85%, 90%, or 95% of the particles. (Item 50) 50. The method of claim 28, 44, 45, or 48, further comprising separating the isolated particles from the paramagnetic medium. (Item 51) 29. The method of claim 28, wherein the particle comprises a biomolecule, a cell, a group of cells, a protein, a lipid, a carbohydrate, a microorganism, or a bacterium. (Item 52) 1. A method for isolating particles, comprising: a) forming a treatment solution containing the particles and a paramagnetic medium; b) passing the processing solution through a particle isolation device, the device comprising a fluid channel structure comprising a series of fluid channels and at least two processing compartments, each of the at least two processing compartments comprising at least two magnetic components positioned on opposite sides of a portion of the fluid channel, the two magnetic components generating asymmetric magnetic fields within their corresponding portions of the fluid channel, whereby a portion of the processing solution passes through the at least two processing compartments in parallel and / or a portion of the processing solution or all of the processing solution passes through the at least two processing compartments in series, thereby isolating the particles as they pass through the asymmetric magnetic fields of the processing compartments; c) observing, analyzing, recording, and / or collecting said isolated particles; A method comprising: (Item 53) (i) the fluid channel structure comprises at least one input port and at least two output ports interconnected by the series of fluid channels, the series of fluid channels comprising a first generally linear portion, a second generally linear portion, and a third generally linear portion, and the fluid channel structure comprises: A.(i) a first processing path extending from the at least one input port to the first substantially linear portion, extending from the first substantially linear portion to the second substantially linear portion, and extending from the second substantially linear portion to an output port of the at least two output ports; B.(ii) a second processing path extending from the at least one input port to the first substantially linear portion, extending from the first substantially linear portion to the third substantially linear portion, and extending from the third substantially linear portion to an output port of the at least two output ports; Including, (ii) a first pair of magnetic components, a second pair of magnetic components, and a third pair of magnetic components positioned generally perpendicular to opposite sides of the first generally linear portion, the second generally linear portion, and the third generally linear portion, respectively, wherein at least one of the first pair of magnetic components, the second pair of magnetic components, and the third pair of magnetic components is configured to generate an asymmetric magnetic field within its adjacent generally linear portion; (iii) optionally, one or more pumps are configured to drive fluid from the at least one input port through the series of fluid channels and out the at least two output ports; (iv) The method of claim 52, wherein the method comprises passing a portion of the processing solution through the first processing path and passing a portion of the processing solution through the second processing path, whereby there is a first isolation of particles as the particles pass through the asymmetric magnetic field in the first approximately linear portion and there is a second isolation of particles as they pass through the asymmetric magnetic field of either the second approximately linear portion or the third approximately linear portion. (Item 54) A particle isolation device comprising a channel, one end of which branches into at least two channels, the two channels being approximately parallel to each other within the particle isolation device, and a magnet positioned between the two approximately parallel channels, the magnet configured to separate particles within the channels by magnetic force. (Item 55) A particle isolation device comprising an array of wells and an array of magnets, wherein a first magnet in the array of magnets is positioned between a first well and a second well in the array of wells, and the first magnet is configured to separate particles in the first well and the second well. (Item 56) 56. The particle isolation device of claim 55, wherein the particle isolation device is configured to circulate a fluid sample within the first well. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 is an illustration of the magnetic field present in a prior art device.

[0038] [Figure 2] FIG. 2 is an illustration of the magnetic field present in a device according to the present invention.

[0039] [Figure 3] 3A and 3B are illustrations of a shifted neutral resulting from an asymmetric magnetic field in accordance with the present invention.

[0040] [Figure 4] 4A and 4B are illustrations of the effect of a shifted neutral on particle isolation in accordance with the present invention.

[0041] [Figure 5] FIG. 5 is a plan view of an alternative embodiment of a particle isolation device in accordance with the present invention.

[0042] [Figure 6] FIG. 6 is a plan view of an alternative embodiment of a particle isolation device in accordance with the present invention.

[0043] [Figure 7]FIG. 7 is a cross-sectional view of the capillary 32 at the end 60 of the processing compartment 50 taken along line 7-7 of FIG.

[0044] [Figure 8] FIG. 8 is an alternative embodiment of a cross-sectional view of the capillary 32 at the end 60 of the processing compartment 50 taken along line 7-7 of FIG.

[0045] [Figure 9] FIG. 9 is a plan view of an alternative embodiment of a particle isolation device in accordance with the present invention.

[0046] [Figure 10] FIG. 10 is a perspective view of an alternative embodiment of a particle isolation device in accordance with the present invention.

[0047] [Figure 11] FIG. 11 is a diagram of the particle isolation device shown in FIG. 10 with some internal details visible.

[0048] [Figure 12] FIG. 12 is an enlarged perspective view of a portion of the particle isolation device shown in FIG.

[0049] [Figure 13] FIG. 13 is a perspective view of an alternative embodiment of a particle isolation device in accordance with the present invention.

[0050] [Figure 14] FIG. 14 is an enlarged perspective view of the distal end of processing channel 78 shown in FIG.

[0051] [Figure 15] FIG. 15 is a perspective view of an alternative embodiment of a particle isolation device in accordance with the present invention.

[0052] [Figure 16] FIG. 16 is a cross-sectional view of the device shown in FIG. 15 taken along line BB, with magnet 116 shown.

[0053] [Figure 17] 17A and 17B are perspective views of alternative magnet configurations of a particle isolation device in accordance with the present invention.

[0054] [Figure 18] FIG. 18 is a perspective view of an alternative magnet configuration of a particle isolation device in accordance with the present invention.

[0055] [Figure 19] FIG. 19 is a perspective view of an alternative embodiment of a particle isolation device in accordance with the present invention.

[0056] [Figure 20] FIG. 20 is a perspective view of an alternative embodiment of a particle isolation device in accordance with the present invention.

[0057] [Figure 21] FIG. 21 is a perspective view of an alternative embodiment of a particle isolation device in accordance with the present invention.

[0058] [Figure 22] 22A and 22B are cross-sectional views of a prior art fluid channel (FIG. 22A) and a prior art fluid channel (FIG. 22B) according to an embodiment of the present invention.

[0059] [Figure 23] FIG. 23 is a photograph illustrating the isolation of particles according to the present invention.

[0060] [Figure 24] FIG. 24 is a graph showing the particle distribution of the isolated particles shown in FIG.

[0061] [Figure 25] FIG. 25 is a conceptual diagram of a branched parallel channel device with a shared central magnet.

[0062] [Figure 26]FIG. 26 is a conceptual diagram of a well assay particle separation device in which magnets are shared between adjacent wells.

[0063] [Figure 27] FIG. 27 illustrates the difference in particle density (gm / cm3) versus position along the z-axis (cm). DETAILED DESCRIPTION OF THE INVENTION

[0064] I. Definition / Term The following definitions are provided to aid in understanding the present invention. Unless otherwise defined, all technical terms, notation, and other scientific or engineering terms or glossaries used herein are intended to have meanings commonly understood by those of ordinary skill in the art. In some cases, terms with commonly understood meanings are defined herein for clarity and / or ease of reference, and the inclusion of such definitions herein should not be assumed to represent a substantial difference from what is generally understood within the art, but is intended to supplement such general understanding. To the extent that a definition herein contradicts what is generally understood within the art, both the definition provided herein and what is generally understood within the art shall be considered to fall within the scope of the present invention as alternative embodiments, unless expressly stated otherwise.

[0065] As used herein, unless otherwise indicated, open-ended terms such as "contain," "containing," "include," "including," and the like, mean "comprising."

[0066] Some embodiments herein contemplate numerical ranges. When numerical ranges are provided, the ranges include the range endpoints unless otherwise indicated. Unless otherwise indicated, numerical ranges include all values ​​and subranges therein, as if explicitly written out.

[0067] As used herein, the article "a" means "one or more" unless expressly stated otherwise.

[0068] Some values ​​herein are modified by the term "about." In some instances, the term "about" in connection with a reference numerical value can include a range of values ​​from that value plus or minus 10%. For example, the quantity "about 10" can include amounts from 9 to 11. In other embodiments, the term "about" in connection with a reference numerical value can include a range of values ​​from that value plus or minus 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1%. When a series of values ​​is preceded by the term "about," it is intended that the term modify each value in the series.

[0069] As used herein, the term "asymmetric" with respect to a magnetic field means that the magnetic field within the region of the associated fluid channel is not symmetric about one or more planes passing through the center of the fluid channel, and according to a preferred embodiment, is not symmetric about a horizontal plane.

[0070] As used herein, the terms "capillary," "microcapillary," or "capillary tube" refer to a tube having a channel as defined herein below.

[0071] As used herein, the terms "channel," "flow channel," "fluid channel," and "fluidic channel" are used interchangeably and refer to a pathway on a fluidic device through which a fluid may flow. A channel includes a pathway with a maximum internal dimension (e.g., height or thickness) of about 30 mm, about 25 mm, about 20 mm, about 15 mm, about 10 mm, about 5 mm, about 5 mm, about 3 mm, about 2 mm, about 1 mm, or about 0.5 mm. The internal height of a channel may not be uniform across its cross-section, and geometrically, the cross-section may be any shape, including circular, square, oval, rectangular, or hexagonal. The term "channel" includes, but is not limited to, microchannels and nanochannels, and with respect to any reference to a channel herein, such a channel may comprise a microchannel or a nanochannel.

[0072] As used herein, the term "concentration" refers to the amount of a first component contained within a second component, and may be based on the number of particles per unit volume, the amount of moles per unit volume, the weight per unit volume, or the volume of the first component per volume of the composite component.

[0073] As used herein, the terms "fluidly coupled" or "fluid communication" mean that fluid can flow between two components that are so coupled or in communication.

[0074] As used herein, the terms "isolate" or "isolating" with reference to a component means separating such component from other components and includes a combination of increasing the concentration of the component in a solution, or separating the component from other components in a solution, or increasing the concentration of the component in a solution while separating such component from other components in a solution. A particle in a solution is considered "isolated" if it is separated from other particles in the solution and / or located within a defined portion of the solution. A particle or component in a solution is also considered "isolated" if, after processing the solution, the concentration of such particle or component is increased by a ratio of at least about 100:1, 90:1, 80:1, 70:1, 60:1, 50:1, 40:1, 30:1, 20:1, 10:1, 5:1, or 2:1. A particle of interest in a solution containing other particles is considered "isolated" if, after processing such solution, the ratio of the concentration of such particle of interest to the concentration of such other particles is increased, or the ratio of the concentration of such particle of interest to the concentration of such other particles is increased by at least about 50%, 100%, 200%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, or 1000%, or the concentration of such other components is reduced to less than about 50%, 20%, 15%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, or 0.5% relative to their initial concentration or as a percentage of similarly sized particles that remain present.

[0075] As used herein, the term "fluidic" refers to a system, device, or element for handling, processing, releasing, and / or analyzing a fluid sample that includes at least one "channel" as defined herein above. The term "fluidic" includes, but is not limited to, microfluidic and nanofluidic.

[0076] As used herein, the term "fluidic function" refers to any operation, function, or process performed on or exhibited by a fluid or sample within a fluidic system, including, but not limited to, filtration, pumping, fluid flow regulation, fluid flow control, and the like.

[0077] As used herein, the term "particle" refers to any substance, including but not limited to, an atom, chemical element, molecule, compound, biomolecule, cell, protein, lipid, carbohydrate, microorganism, bacteria, or any physical substance, whose largest dimension in any direction is less than about 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm, less than 0.25 mm, less than 100 microns, less than 75 microns, less than 50 microns, less than 40 microns, less than 30 microns, less than 20 microns, or less than 10 microns.

[0078] As used herein, the term "port" refers to a structure for providing fluid communication between two elements, for example, using a fluid channel.

[0079] Although the methods and steps described herein show certain events occurring in a certain order, those skilled in the art will recognize that the ordering of certain steps may be modified and that such modifications are in accordance with variations of the present invention. In addition, certain steps may be performed sequentially as well as in parallel in parallel processes when possible. II. Asymmetric magnetic field

[0080] The present disclosure provides a device for isolating particles by using magnetic levitation. Magnetic levitation refers to the use of a magnetic field to counteract the force of gravity on particles, thereby raising or lowering the particles to an equilibrium altitude within a medium. The equilibrium altitude for any given particle can be determined by a number of factors, including the relative magnetic susceptibility of the particle and the medium, the relative densities of the particle and the medium, the size of the particle, and the strength of the magnetic field. Once the particles reach their equilibrium altitude, various fractions can then be collected to isolate the particles, or alternatively, various treatments can then be targeted to one or more fractions, thereby isolating the particles within the fractions. According to a preferred embodiment, such fractions comprise approximately vertical separations along the height of a fluid channel containing the particles and the medium.

[0081] In certain embodiments, the device includes a fluid channel and a magnetic field source configured to exert an asymmetric magnetic force along at least a portion of the fluid channel. The asymmetry in the magnetic force exists along at least one axis of the fluid channel. Preferably, the magnetic force is asymmetric along at least the vertical axis of the fluid channel. Alternatively, the magnetic force is asymmetric only along the vertical axis of the fluid channel. In other embodiments of the invention, the magnetic force is asymmetric along the vertical axis of the fluid channel and at least one additional axis of the fluid channel, or the magnetic force is asymmetric along all three axes of the fluid channel.

[0082] According to prior art devices, identical magnets are placed symmetrically above and below a fluid channel with their magnetic poles in a repulsive orientation, thereby resulting in symmetric magnetic forces along the vertical axis of the fluid channel. The magnetic field lines 2 of two opposing identical magnets according to such prior art devices are illustrated in Figure 1. When identical magnets are utilized as shown in Figure 1, a neutral line 4 (or zero field plane) will occur at a vertical position midway between the two magnets, where the forces exerted by the two opposing magnets cancel each other out.

[0083] According to one embodiment of the present invention, a magnet configuration is used in which the force exerted on a particle on one side of a fluid channel is greater than the force exerted on the same particle on the other side of the fluid channel, thereby resulting in an asymmetric magnetic force perpendicular to the fluid channel. This force imbalance can be achieved by using one stronger magnet or by using multiple magnets on one side of the fluid channel. The stronger magnet can be achieved by using a single magnet with a similar geometry but stronger internal magnetization, or by using magnets with larger axial dimensions and identical magnetization. Figure 2 illustrates the magnetic field lines 2 of two opposing magnets in accordance with the present invention, where the lower magnet 8 is stronger than the upper magnet 10. As illustrated in Figure 2, the neutral line 6 is vertically biased, or biased toward the weaker magnet. Figures 3A and 3B illustrate how this neutral line bias would affect the magnetic field lines 2 that arise within the fluid channel 12 interposed between the upper magnet 10 and the lower magnet 8. Figure 3A illustrates a prior art configuration, and Figure 3B illustrates a configuration according to the present invention. As illustrated in Figure 3B, the use of a larger magnet below the fluid channel shifts or biases the neutral line 6 upward toward the weaker upper magnet 10 compared to the configuration shown in Figure 3, where the magnets impart a symmetric magnetic field, resulting in a symmetric neutral line 4 occurring at the vertical midpoint between the two magnets with the same magnetic strength.

[0084] For a given grade of magnet, fully magnetized during manufacturing, the surface field strength at the pole surface increases with the magnet's dimension in the direction parallel to the magnetization. Thus, by keeping two of the magnet dimensions fixed but increasing the separation or length of the magnetic field axis (i.e., the vertical axis), the strength of the magnet can be increased. In a symmetric configuration, this can simply increase the field or gradient at any point. For example, in an asymmetric configuration where only the bottom magnet is increased, the zero field plane or neutral line between opposing magnets can be pushed (upward) toward the weaker magnet.

[0085] 4A and 4B illustrate an example of how vertical displacement of the neutral lines 4, 6 affects the operation of a levitation device according to the present invention to isolate a first particle 14 and a second particle 16. In particular, according to the present invention, particles of interest are combined with a magnetically responsive medium and passed through a fluid channel flanked by magnets positioned above and below the fluid channel. All particles within the magnetically responsive medium, which is denser than the medium itself, will levitate at a position below the neutral line. As illustrated in FIG. 4B, the use of an asymmetric magnetic field according to the present invention and the resulting displacement of the upward neutral line 6 avoids constraining the spread of levitation height to just half the available vertical space between the magnets (as in the prior art device shown in FIG. 4A), allowing for a wider field for particle separation and a wider field for optical visualization of the separation. Furthermore, the present invention allows for larger fluid flows because a larger volume of the fluid channel can be utilized.

[0086] Conversely, the primary particles of interest may be less dense than the magnetically responsive medium, and a symmetric magnetic field may limit particle isolation to the upper half of the fluid channel. Thus, in such applications, a magnetic configuration can be used that applies a larger magnetic field to the upper side of the fluid channel, thereby shifting the neutral line downward. III. Levitation Device

[0087] Levitation devices according to the present invention can include an input portion, a processing portion, and an output portion. The levitation device may include a component configuration in which the input, processing, and output portions each include individual interconnected components. Alternatively, the levitation device may include an integrated configuration in which portions of the input, processing, and output portions are integrated into a single component, such as a fluidic chip. Component configurations of levitation devices according to the present invention are illustrated in Figures 5-6, and integrated configurations are illustrated in Figures 9-16. A. Component Configuration

[0088] 5 and 6, various embodiments of the levitation device 20 of the present invention are shown in which the input, processing, and output portions of the device comprise separate, individual components that are interconnected. FIG. 5 illustrates an embodiment in which the asymmetric magnetic field is achieved by including one larger magnet 36 on one side of the fluid channel 34. FIG. 6 illustrates an embodiment in which the asymmetric magnetic field is achieved by including two magnets 40 on one side of the fluid channel 34, the two magnets 40 being positioned in an attractive rather than repulsive arrangement. Combining two magnets in the manner shown in FIG. 6 provides a slightly lower field strength than a monolithic single part 38 as shown in FIG. 5, but still results in an effective asymmetric magnetic field.

[0089] 5, levitation device 20 includes a support structure and a support structure mounting means. According to the illustrated embodiment, the support structure comprises support structure 22, with support structure mounting means comprising a plurality of mounting holes 24 and mounting posts 26. The input portion of the device comprises input manifold 28. The output portion of the device comprises output manifold 42. Input manifold 28 and output manifold 42 are mounted to support structure 22 using input manifold mounting means 30 and output manifold mounting means 44, respectively, which in the illustrated embodiment comprise mounting holes and screws. Capillaries 32 are mounted on the input and output manifolds via retaining slots contained therein.

[0090] The processing portion of the device includes a capillary 32, an upper magnet 36, and a lower magnet 38. The capillary 32 includes a fluid channel 34 extending therethrough along its length. The upper magnet 36 and the lower magnet 38 are mounted on the support structure 22 such that they are positioned adjacent to the fluid channel 34, with the upper magnet 36 positioned above the capillary 32 and the lower magnet 38 positioned below the capillary 32. The upper magnet 36, the lower magnet 38, and the capillary 32 are generally horizontally parallel and aligned along a generally vertical axis. According to one embodiment, the capillary 32 may be vertically centered between the upper magnet 36 and the lower magnet 38, as illustrated in FIG. 5. Alternatively, the capillary 32 may be vertically offset between the upper magnet 36 and the lower magnet 38 so that it is vertically closer to one of the two magnets, as illustrated in FIG. 6.

[0091] The upper magnet 36 and the lower magnet 38 are configured to generate an asymmetric magnetic field within the fluid channel 34. The asymmetric magnetic field is achieved by selecting a magnet configuration in which the magnetic field generated within the fluid channel from one of the magnets is greater than the magnetic field generated by the other magnet. As described in more detail herein below, this can be achieved by using a variety of different magnetic configurations based on the size of the magnets, the number of magnets, the type of magnet (e.g., magnetic material), or the spacing of the magnets relative to the fluid channel. As shown in FIG. 5, the upper magnet 36 is larger than the lower magnet 38 and therefore generates a larger magnetic field within the fluid channel 34. As shown in FIG. 6, the lower magnet 38 comprises two smaller magnets that are the same size as the upper magnet 36, and therefore the combined two lower magnets generate a larger magnetic field within the fluid channel 34. Additionally, the strength of the magnetic field generated within the fluid channel 34 by the lower magnet 38 in FIG. 6 is enhanced by vertically positioning the lower magnet 38 closer to the fluid channel 34 than the upper magnet 36.

[0092] According to one embodiment, the capillary 32 comprises an input opening 46, an output opening 48, and a fluid channel processing compartment 50. The processing compartment 50 comprises a generally linear fluid channel in fluid communication with the input opening 46 and the output opening 48. In some cases, the processing compartment 50 is further defined as that portion of the fluid channel aligned between the upper magnet 36 and the lower magnet 38 or 40. The capillary 32 may include a splitter that divides the fluid channel into multiple channels. The splitter is preferably positioned within the processing compartment 50 but near a terminal end 60 of the processing compartment so that any particle isolation achieved by passing the fluid between the magnets is maintained as the fluid exits the device. The splitter may comprise one or more generally horizontal partitions extending from the terminal end 60 of the processing compartment 50 to the output opening 48. The horizontal partition 56 of the splitter 54 is illustrated in FIG. 7, which is a cross-sectional view of the capillary 32 at the terminal end 60 of the processing compartment 50 taken along line 7-7 in FIG. 5. According to an embodiment incorporating the splitter shown in Figure 7, four vertical fractions will be collected at the output opening 48. In addition, the splitter may include one or more vertical partitions, thereby creating a horizontal and vertical grid of outflow fluid channels (see Figure 8) that lead to the output opening 48. B. Integral composition

[0093] Alternatively, the levitation device may comprise an integrated configuration in which portions of the input, processing, and output portions are integrated into a single component, such as a fluidic chip. As shown in Figures 9, 10, and 13, the input manifold, fluidic channels, and output manifold may comprise a single integrated fluidic component 64. In accordance with this embodiment, the levitation device comprises an integrated fluidic component, an upper magnet, and a lower magnet. The integrated fluidic component 64 may comprise a fluidic cartridge (Figures 10 and 15) or a chip (Figure 13), which may be a single-use disposable unit.

[0094] 9, 10, and 13, in a preferred embodiment, levitation device 20 comprises an integrated fluidic component 64, a support structure 22, an upper magnet 36, and a lower magnet 38. As shown in FIG. 9, integrated fluidic component 64, upper magnet 36, and lower magnet 38 may be mounted on support structure 22. Integrated fluidic component 64 comprises an input section 66, an output section 68, and a central processing section 70 positioned between input section 66 and output section 68. A fluidic channel structure 72 extends through input section 66, output section 68, and central processing section 70.

[0095] The input section 66 includes one or more inlet ports 74 in fluid communication with the fluid channel structure 72. The input section 66 may also include one or more input valves 76 (shown in FIG. 13). The input valves 76 may be included to allow control of communication of the inlet ports with the fluid channel structure 72. In some embodiments, the input valves 76 are positioned within the channel and adjacent to the inlet ports 74. The input section 66 may also include one or more pumps 96, as illustrated in FIG. 13.

[0096] The fluid channel extends from the inlet port 74 through the input section 66 into a processing channel 78 that extends through the central processing section 70. The central processing section 70, together with the upper magnet 36 and the lower magnet 38, form the processing portion of the device, which is the functional portion of the device where particles of interest are exposed to a magnetic field and thereby isolated. As explained more fully below, the upper magnet 36 and the lower magnet 38 are positioned adjacent to the processing channel 78 that extends through the processing section 70 such that the upper magnet 36 and the lower magnet 38 generate an asymmetric magnetic force across the processing channel 78. For improved operability and manufacturability, the central processing section 64 can be offset in the z-axis from the plane of the input section 60 or the output section 62 to maintain fluid connections throughout the device.

[0097] Processing channel 78 is preferably an elongated fluid channel having a sufficient length along the x-axis (shown in FIG. 13) to allow sufficient time to process the fluid containing the particles of interest based on the residence time required for the particles to more closely approach altitude equilibrium (along the y-axis) within processing channel 78 and based on the desired throughput from the system. According to certain embodiments, the processing channel is a fluid channel having an altitude of about 200 microns to about 30 mm, about 200 microns to about 20 mm, about 200 microns to about 15 mm, about 200 microns to about 10 mm, about 200 microns to about 5 mm, about 200 microns to about 2 mm, about 200 microns to about 1 mm, about 0.5 mm to about 1 mm, about 0.5 mm to about 2 mm, about 0.5 mm to about 3 mm, about 1 mm to about 2 mm, about 1 mm to about 3 mm, or about 1.5 mm to about 2 mm. According to certain embodiments, processing channel 78 has a length of about 20 mm to about 200 mm, about 20 mm to about 150 mm, about 20 mm to about 100 mm, about 20 mm to about 50 mm, about 40 mm to about 100 mm, about 40 mm to about 90 mm, or about 40 mm to about 80 mm. Processing channel 78 may have any cross-sectional geometry, including square, rectangular, circular, or oval cross-sectional geometries. The geometric characteristics of processing channel 78 described herein are equally applicable to capillary 32 and fluidic channel 34, described above with reference to the component configurations of the present invention.

[0098] According to a preferred embodiment, the processing channel 78 terminates with one or more channel dividers 80, which act as splitters. The device may include vertically spaced, generally horizontal partitions within the terminal portion of the processing channel 78, and may include multiple channel dividers 80 defining multiple vertically spaced compartments 82 along the terminal portion of the processing channel 78. Alternatively, the channel divider may also include one or more horizontally spaced, generally vertical partitions 84 defining multiple horizontally spaced compartments, so as to create an exit grid as illustrated in FIG. 8. The splitters enable the collection of various fractions of the fluid being processed by the device, thereby allowing isolated particles to be collected in a given fraction based on the equilibrium position of the isolated particles within the fluid.

[0099] The magnetic field generated by the upper magnet 36 and the lower magnet 38 along the x-axis of the processing channel 78 is strongest at the center point along the x-axis. As the processing fluid moves along the processing channel 78 toward the end portion of the processing channel 78, the magnetic field may begin to attenuate, and the orientation may also vary. As the fluid path passes through this more spatially variable magnetic field, there may be a tendency for isolated particles to begin migrating from their equilibrium altitude. This tendency may be exacerbated once the particles move beyond the magnets. Thus, according to a preferred embodiment, the channel divider 80 extends from the end of the processing channel 78 back into the processing channel 78 and back into at least a portion of the processing channel between the end portion of the upper magnet 36 and the end portion of the lower magnet 38, as illustrated in FIG. 14, which is an enlarged perspective view of the end of the processing channel 78 shown in FIG. 13. This configuration can enable permanent separation of isolated particles before spatial variations in the magnetic field result in degradation of isolation. The level of magnetic field attenuation can be a function of the distance between the upper and lower magnets. Thus, according to preferred embodiments, channel divider 80 overlaps with end portions of upper magnet 36 and lower magnet 38 along the x-axis of the device by a distance that is at least about 10% to about 300%, or about 20% to about 280%, or about 30% to about 260%, or about 40% to about 240%, or about 50% to about 220%, or about 60% to about 200%, or about 70% to about 180%, or about 80% to about 160% of the size of the gap between the upper and lower magnets.

[0100] The channel divider defines a plurality of outlet fluid channels 88 (see FIGS. 9, 11, 12, and 14). According to certain embodiments, the levitation device of the present invention includes a splitter that defines 2, 3, 4, 5, 6, 7, 8, 9, or 10 outlet fluid channels. According to certain embodiments, the levitation device of the present invention includes a splitter that defines at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 outlet fluid channels. According to certain embodiments, the levitation device of the present invention includes a splitter that defines 2 to 4, 5 to 7, or 8 to 10 outlet fluid channels. The splitters and various resulting outlet fluid channels described herein may be incorporated into the capillaries 32 and fluid channels 34 described above with reference to the component configurations of the present invention.

[0101] A plurality of outlet fluid channels extend from the processing channel 78 to a corresponding plurality of outlet ports 90. The plurality of outlet fluid channels may include fluid flow controllers, such as output valves 94, that control the flow rate from the processing channel 78 through the individual outlet channels to the individual outlet ports.

[0102] An alternative embodiment of a fluidic cartridge 98 according to the present invention is shown in FIGS. 15 and 16 . FIG. 16 is a cross-sectional view of the device shown in FIG. 15 taken along line BB. According to this embodiment, an inlet port 100 is included that is in fluid communication with an internal fluidic structure 102 that includes a fluidic channel processing compartment 104. The fluidic cartridge 98 also includes two recessed portions 106 adjacent to the fluidic channel processing compartment 104 (shown in FIG. 15 ) and adapted to receive magnets 116 (shown in FIG. 16 ). The fluidic structure 102 includes a splitter 108 that divides the fluidic channel processing compartment 104 into two outlet channels 110 that each lead to an outlet port 112. The fluidic cartridge 98 also includes a visualization window 114 positioned adjacent to the fluidic channel processing compartment 104. The visualization window 114 may comprise a substantially transparent window adapted to allow an optical device, such as the device shown in Figure 21, to facilitate observation and / or video recording of particles as they are exposed to the magnetic field within the fluid channel processing compartment 104. The visualization window 114 may also comprise a sufficiently transparent section of the channel so that visualization of the contents is achievable. C. Magnet configuration

[0103] According to preferred embodiments, magnets are positioned above and below the capillary 32 (FIGS. 5 and 6) or central processing section 70 (FIGS. 9 and 13) and are positioned in a magnetically repulsive orientation relative to one another to generate a magnetic field perpendicular to and across the fluid channel 34, the magnetic field within the fluid channel 34 being asymmetric along at least the vertical direction. According to certain embodiments, the magnets are centered with the fluid processing channel along its length (i.e., along the x-axis shown in FIG. 13).

[0104] According to a preferred embodiment, at least one of the upper magnet 36 or the lower magnet 38 is configured to generate a larger magnetic field on the fluid channel 34 than the other magnet, thereby resulting in an asymmetric magnetic force within the fluid channel 34, as illustrated, for example, in FIG. 3B. This larger force can be achieved by either (1) using a larger magnet on one side of the fluid channel 34 (as illustrated by the larger upper magnet 36 in FIG. 5), (2) including multiple magnets on one side of the fluid channel 34 (in an attractive rather than repulsive arrangement relative to each other) (as illustrated by the lower magnet 40 in FIG. 6), (3) positioning one of the two magnets closer to the fluid channel 34 than the other magnet (as illustrated in FIG. 6), or (4) some combination thereof.

[0105] According to certain embodiments, one or both of the upper magnet 36, the lower magnet 38, or the lower magnet 40 are movably mounted within the system to allow controlled adjustment of the magnet's vertical position relative to the fluid channel 34 and to allow adjustment of the magnetic field asymmetry. According to certain embodiments, the levitation device includes an upper magnet or a lower magnet with multiple magnets movably mounted so that the number of magnets engaged (i.e., actively generating a magnetic field across the processing section of the fluid channel) can be controlled, thereby controlling the magnitude and gradient profile of the magnetic field. Control over the magnetic field as a function of time can enable more complex protocols that can be changed at any time during an experiment or assay. Among other advantages over static systems, this can enable more flexible sample sectioning, higher resolution in particle separation, more flexible methods for purging, priming, and treating the fluid path, and feedback to optimize or change separation parameters as the experiment or assay is run.

[0106] According to certain embodiments, the upper magnet 36 and the lower magnet 38 comprise elongated rectangular magnets (preferably bar magnets) having dimensions ranging from about 2 mm to about 25 mm in height (y-axis (vertical axis) from FIG. 13), about 30 mm to about 80 mm in width (x-axis from FIG. 13), and about 0.5 mm to about 7 mm in depth (z-axis from FIG. 13). Preferably, the upper magnet 36 and the lower magnet 38 have dimensions ranging from about 4 mm to about 20 mm in height (y-axis from FIG. 13), about 40 mm to about 60 mm in width (x-axis from FIG. 13), and about 1 mm to about 3 mm in depth (z-axis from FIG. 13). The preferred magnet sizes described herein can be achieved by a single magnet or by combining multiple magnets. According to certain embodiments, the upper magnet 36 and the lower magnet 38 have dimensions ranging from about 4 mm to about 20 mm in height (y-axis from FIG. 13), about 40 mm to about 60 mm in width (x-axis from FIG. 13), and about 1 mm to about 3 mm in depth (z-axis from FIG. 13). The depth and width of the upper magnet 36 and the lower magnet 38 are substantially the same. According to certain embodiments, the elevation of the upper magnet 36 is at least about 25%, 50%, 75%, 100%, 125%, 150%, 175%, 200%, 225%, 250%, 275%, 300%, 325%, 350%, 375%, 400%, 425%, 450%, 475%, or 500% greater than the elevation of the lower magnet 38. According to some embodiments, the height of the upper magnet 36 is about 25% to about 100%, about 100% to about 200%, about 200% to about 300%, about 300% to about 400%, about 400% to about 500%, or about 500% to about 600% greater than the height of the lower magnet 38. According to some embodiments, the height of the lower magnet 38 is at least about 25%, 50%, 75%, 100%, 125%, 150%, 175%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 600%, 650%, 700%, 800%, 850%, 900%, 950%, 1000%, 1100%, 1250%, 1300%, 1400%, 1500%, 1600%, 1750%, 1800%, 1900%, 2000%, 2500%, 3000%, 4000%, 5000%, 6500%, 7000%, 8500%, 9000%, 1000%, 1150%, 1250%, 1300%, 1400%, 1500%, 1650%, 1750%, 1850%, 1900%, 2000%, 2500%, 3000%, 4000%, 5000%, 6500%, 1900%, 20 ... 00%, 225%, 250%, 275%, 300%, 325%, 350%, 375%, 400%, 425%, 450%, 475%, or 500% greater. According to certain embodiments, the height of the lower magnet 38 is between about 25% and about 100%, between about 100% and about 200%, between about 200% and about 300%, between about 300% and about 400%, between about 400% and about 500%, or between about 500% and about 600% greater than the height of the upper magnet 36.

[0107] In some embodiments, the distance along the vertical axis between the upper and lower magnets and the fluid channel 34, capillary 32, or central processing section 70 is at least about 1 micron, 10 microns, 50 microns, or 100 microns, and / or not more than about 500 microns, 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm. In some embodiments, the distance along the vertical axis between either of the magnets and the fluid processing channel is between about 1 micron and about 5 mm, preferably between about 10 microns and about 2 mm.

[0108] In some embodiments, the vertical distance between the upper magnet and the fluid treatment channel is at least about 25%, 50%, 75%, 100%, 125%, 150%, 175%, 200%, 225%, 250%, 275%, 300%, 325%, 350%, 375%, 400%, 425%, 450%, 475%, or 500% greater than the vertical distance between the lower magnet and the fluid treatment channel. In some embodiments, the vertical distance between the upper magnet and the fluid treatment channel is at least about 25% to about 100%, about 100% to about 200%, about 200% to about 300%, about 300% to about 400%, about 400% to about 500%, or about 500% to about 600% greater than the vertical distance between the lower magnet and the fluid treatment channel.

[0109] In some embodiments, the vertical distance between the lower magnet and the fluid treatment channel is at least about 25%, 50%, 75%, 100%, 125%, 150%, 175%, 200%, 225%, 250%, 275%, 300%, 325%, 350%, 375%, 400%, 425%, 450%, 475%, or 500% greater than the vertical distance between the upper magnet and the fluid treatment channel. In some embodiments, the vertical distance between the lower magnet and the fluid treatment channel is at least about 25% to about 100%, about 100% to about 200%, about 200% to about 300%, about 300% to about 400%, about 400% to about 500%, or about 500% to about 600% greater than the vertical distance between the upper magnet and the fluid treatment channel.

[0110] In some embodiments, the upper magnet 36 and the lower magnet 38 are permanent magnets or electromagnets. In some embodiments, the maximum energy product of the upper magnet 36 and the lower magnet 38 ranges from about 1 megagauss-oersted to about 1,000 megagauss-oersted, and more preferably from about 1 megagauss-oersted to about 5 megagauss-oersted. In some embodiments, the surface magnetic field strength of the upper and lower magnets ranges from about 0.1 tesla to about 100 tesla, and more preferably from about 1 tesla to about 10 tesla. In some embodiments, the remanence of the upper and lower magnets ranges from about 0.5 tesla to about 5 tesla, and more preferably from about 1 tesla to about 3 tesla.

[0111] According to preferred embodiments, the upper magnet 36 and the lower magnet 38 are made from materials including neodymium alloys with iron and boron, neodymium, neodymium alloys with iron, samarium-cobalt, other alloys of rare earth elements with iron, alloys of rare earth alloys with nickel, ferrite, alloys of aluminum with iron, or combinations thereof. According to certain embodiments, the upper magnet 36 and the lower magnet 38 are made from the same material or from different materials.

[0112] According to a preferred embodiment, an asymmetric magnetic field is achieved by using a stronger magnetic material on one side of the fluid channel and a weaker magnetic material on the other side of the fluid channel. According to such an embodiment, the upper magnet 36 and the lower magnet 38 may be substantially the same size, yet still produce an asymmetric magnetic force across the fluid channel 34. According to such an embodiment, the upper magnet 36 may comprise neodymium and the lower magnet 38 may comprise samarium-cobalt, with both magnets being substantially the same size. Alternatively, the upper magnet 36 may comprise samarium-cobalt and the lower magnet 38 may comprise neodymium, with both magnets being substantially the same size.

[0113] According to certain embodiments, alternative magnet configurations may be used. Referring to FIG. 17A , a device according to the present invention may include multiple upper magnets and multiple lower magnets positioned around a fluid channel. The upper magnets may include a front upper magnet 118, a center upper magnet 120, and a rear upper magnet 122. The lower magnets may include a front lower magnet 126, a center lower magnet 128, and a rear lower magnet 130. As illustrated in FIG. 17A , references to the magnets as front, rear, and center refer to the position of the magnets along the z-axis relative to the fluid channel 124, and references to the magnets as upper and lower refer to the position of the magnets along the y-axis relative to the fluid channel 124. Arrows 132 indicate the orientation of the magnetic field with respect to magnets 118, 120, 122, 126, 128, and 130; as illustrated, the upper and lower magnets are positioned in a magnetically repulsive orientation.

[0114] According to another embodiment, further alternative magnet configurations may be used. Referring to FIG. 17B, a device according to the present invention may include multiple upper magnets and multiple lower magnets positioned around the fluid channel. The upper magnets may include a front upper magnet 140, a center upper magnet 120, and a rear upper magnet 146. The lower magnets may include a front lower magnet 142, a center lower magnet 128, and a rear lower magnet 144. As illustrated in FIG. 17B, references to the magnets as front, rear, and center refer to the position of the magnets along the z-axis relative to the fluid channel 124, and references to the magnets as upper and lower refer to the position of the magnets along the y-axis relative to the fluid channel 124. Arrows 132 indicate the orientation of the magnetic field relative to magnets 140, 120, 146, 142, 128, and 144, with the three upper magnets in an anti-parallel configuration, the three lower magnets in an anti-parallel configuration, and the central upper and lower magnets positioned in a magnetically repulsive orientation, as shown.

[0115] 18 , another magnet configuration is illustrated. According to this embodiment, the device may include a front upper magnet 334, a rear upper magnet 336, a front lower magnet 338, and a rear lower magnet 340, which are positioned around a fluid channel 342. Arrows 344 indicate the orientation of the magnetic field relative to the magnets, with the front upper magnet 334 and rear lower magnet 340 being positioned in a magnetically repulsive orientation, and the rear upper magnet 336 and front lower magnet 338 being positioned in a magnetically repulsive orientation, as shown. The front and rear magnets modify the magnetic field profile within the channel, improving performance.

[0116] According to the embodiments illustrated in Figures 17A, 17B, and 18, the magnetic fields exerted on the fluid channels 124 and 142 can be asymmetric, preferably asymmetric in the xy plane. The asymmetry can be achieved according to the methods described hereinabove, including by adjusting the position of one or more magnets relative to the fluid channel and / or by using stronger magnets (larger magnets or different magnetic materials) either (1) above the lower magnets, (2) below the upper magnets, (3) before the rear magnets, and / or (4) after the front magnets. According to embodiments having the magnetic configuration illustrated in Figure 17A or 17B, the central lower magnet is stronger than the central upper magnet and / or stronger than either or both of the front lower magnet and rear lower magnet. According to embodiments having the magnetic configuration illustrated in Figure 17A or 17B, the central upper magnet is stronger than the central lower magnet and / or stronger than either or both of the front upper magnet and rear upper magnet. D. Series and parallel configurations

[0117] According to certain embodiments, the isolation or levitation devices of the present invention may comprise multiple processing compartments interconnected in series and / or parallel. Such devices with multiple interconnected processing compartments can improve the device's ability to separate particles with higher specificity and to divide the volume of fluid itself over a wider range of ratios. Either parallel or serial configurations may be used to increase the throughput of the device, in the sense that an increased number of samples can be processed within a given time period.

[0118] 19 and 20 , a particle isolation device 148 is shown. The device 148 includes a fluidic channel structure extending therethrough. The fluidic channel structure includes at least one input port 150 and at least two output ports 152 interconnected by a fluidic channel structure comprising a series of fluidic channels 154, a pump 156, and a valve 158. The series of fluidic channels includes a first generally linear portion 160, a second generally linear portion 162, and a third generally linear portion 164. A first processing path, indicated by an upper path dotted line 166 ( FIG. 19 ), extends from the inlet (input) port 150 to the first generally linear portion 160, from the first generally linear portion 160 to the second generally linear portion 162, and from the second generally linear portion 162 to the outlet (output) port 152. A second processing path, indicated by lower path dotted line 168 (FIG. 19), extends from inlet port 150 to first generally linear portion 160, from first generally linear portion 160 to third generally linear portion 164, and from third generally linear portion 164 to outlet (output) port 152. It should be readily understood that generally linear portions 160, 162, and 164 may be designed to be linear primarily for ease of manufacture and operability. In general, they may be curved, provided the magnetic field along their length is suitable for levitation to occur.

[0119] The device 148 further comprises a first pair of magnetic components 170, a second pair of magnetic components 172, and a third pair of magnetic components 174 positioned generally perpendicularly opposite the first generally linear portion 160, the second generally linear portion 162, and the third generally linear portion 164 of the fluid channel structure, respectively. According to an embodiment, an isolation or levitation device is provided having multiple processing compartments interconnected in series and / or parallel, each processing compartment including a pair of magnetic components, at least one of the pair of magnetic components configured to exert asymmetric magnetic forces within its adjacent generally linear portion of the fluid channel. According to this embodiment, the asymmetry of the magnetic forces can be achieved in any manner described hereinabove.

[0120] 19 and 20 , a first pair of magnetic components 170 comprises identical magnets equally spaced from first generally linear portion 160 of the fluid channel, a second pair of magnetic components 172 comprises an upper magnet that is larger than a lower magnet, both magnets equally spaced from second generally linear portion 162 of the fluid channel, and a third pair of magnetic components 174 comprises an upper magnet that is smaller than a lower magnet, both magnets equally spaced from third generally linear portion 164 of the fluid channel. According to this embodiment, the magnetic neutral line in first generally linear portion 160 of the fluid channel is located along the vertical center of the fluid channel, the magnetic neutral line in second generally linear portion 162 of the fluid channel is located below the vertical center of the fluid channel, and the magnetic neutral line in third generally linear portion 164 of the fluid channel is located above the vertical center of the fluid channel.

[0121] Device 148 includes a first splitter 176 positioned at an end 182 of first generally linear portion 160, a second splitter 178 positioned at an end 184 of second generally linear portion 162, and a third splitter 180 positioned at an end 186 of third generally linear portion 164. According to certain embodiments, the first splitter, second splitter, and third splitter split the channel into two or more channels. According to certain embodiments, the first splitter splits the channel into two channels, whereby one of such split channels leads to second generally linear portion 162 and a second of such split channels leads to third generally linear portion 164. Alternatively, such embodiments may include a three-way splitter as the first splitter, and the third channel leads to untreated wastewater.

[0122] According to one embodiment, the first pair of magnetic components 170 is configured to exert a magnetic force along a fluid channel extending within the first generally linear portion 160, where such magnetic force is vertically symmetric about a vertical centerline of such fluid channel. According to this embodiment, the second pair of magnetic components 172 is configured to exert a magnetic force along a fluid channel extending within the second generally linear portion 162, where such magnetic force is vertically asymmetric about a vertical centerline of such fluid channel and biased downward. Also according to this embodiment, the third pair of magnetic components 174 is configured to exert a magnetic force along a fluid channel extending within the third generally linear portion 164, where such magnetic force is vertically asymmetric about a vertical centerline of such fluid channel and biased upward. According to this embodiment, the asymmetry of the magnetic force can be achieved in any manner described hereinabove. According to the embodiment illustrated in Figures 19 and 20, asymmetry is achieved in the fluid channel extending within the second generally linear portion 162 by having the upper magnet 36 larger than the lower magnet 38, and asymmetry is achieved in the fluid channel extending within the third generally linear portion 164 by having the upper magnet 36 smaller than the lower magnet 38.

[0123] In some embodiments, a particle isolation device may comprise one or more sets of a series of parallel channels, giving the device a branched structure, as shown in FIG. 25. In some embodiments of a branched particle isolation device, the parallel fluid channels may share a common central magnet. Optionally, this embodiment may contain a series of shared central magnets between the parallel channels. The magnets may be positioned to generate magnetic fields that modify the nature of the particle separation achieved, as desired. A particle isolation device may comprise at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more magnets. In some embodiments, a particle isolation device may comprise one or more wells for hydrostatic separation of particle mixtures. In some embodiments, adjacent wells or channels will share one or more common magnets. Optionally, multiple magnets may be stacked to create a shaped magnetic field that creates a focusing centerline within the well, as shown in FIG. 26. The magnetic field defining this centerline can serve as a focusing mechanism, allowing particles to be separated into groups, for example, tight groups along the centerline of the well, which may facilitate detection. Magnets surrounding a well or channel may be arranged horizontally to widen particle equilibrium positions. This may proportionally reduce the dynamic range and increase the time required to achieve equilibrium. Stacking multiple magnets adjacent to each well may modify the shape of the magnetic field gradient in a way that steepens the field gradient and improves separation efficiency. Stacked magnet configurations may compress the magnetic field lines and improve performance. In some cases, the sample can be cycled through each well. In some cases, using this in a step-and-hold format may enable batch analysis, which may be useful for diluted samples. Figure 27 shows the density (gm / cm 3 ) versus position along the z-axis (cm).

[0124] The device 148 may also include one or more pumps 156 configured to drive fluid from the input port 150, through the fluidic channels, and out the output port 152. The device 148 may also include one or more valves 158 to allow control of the amount of fluid flowing along the various paths contained within the fluidic channel structure. E. Pump

[0125] According to the present invention, the device may include one or more pumps for driving fluid through the system. The term "pump" is used to refer to any device that applies a pressure differential between different locations within a channel structure. Pumps may be located either on the inlet side of the system (pushing fluid toward the outlet), or on the outlet (pulling fluid from the inlet), or a combination of both. The pressure differential may be positive or negative. The pressure differential may be commonly applied across multiple outlets or inlets, or may be arranged so that each outlet or inlet has a directly applied pressure differential. The pump may be variable to allow control of the applied pressure differential. Pump types include, but are not limited to, positive displacement pumps such as syringe pumps, peristaltic pumps, diaphragm pumps, regulated static pressure sources, gravity-controlled pressure sources such as elevated or depressed volume liquids, and manual pressure sources such as plastic or foil blisters.

[0126] In some embodiments, pumps may be included on the inlet lines generally to drive fluid through the channel structure, and on some (but not all) outlet lines to selectively drive more fluid through certain outlet lines. For example, pumps may be included on one or more outlet lines associated with one or more equilibrium levitation heights of one or more particles of interest. In addition, all outlet lines may include variable pumps that can be activated or deactivated based on one or more expected equilibrium levitation heights of one or more particles of interest. Similarly, external pumps may be controlled to provide variable pressure differentials. F. Additional Device Components

[0127] Levitation or particle isolation devices according to the present invention may also include additional components, as illustrated in FIG. 21 . According to this embodiment, particle isolation device 188 includes an input manifold 194, an output manifold 196, a processing channel 192, and a pair of magnets 190. Magnet 190 is positioned above and below processing channel 192 and is configured to exert a magnetic field across processing channel 192. Magnet 190 and processing channel 192 may be configured according to any of the magnet / channel configurations and embodiments described hereinabove. Device 188 further includes a visualization component 198 and an illumination component 200. Visualization component 198 may include any device that enables or enhances the ability to view and / or record particles in real time as they pass through processing channel 192, thereby enabling observation and / or measurement of particle isolation, including the degree of particle isolation and / or particle isolation rate. Visualization may also include analysis of the size, shape, or other characteristics of the particles and / or other components of the sample. According to certain embodiments, the material used to surround and thereby define the processing channel 192 is transparent or transmissive along at least a section of the processing channel 192 to facilitate observation of particles passing therethrough.

[0128] In one embodiment, the device includes two transparent or transmissive sections, each on opposite sides of the channel 192. According to this embodiment, a visualization component 198 is positioned on one side and focuses one of the transparent or transmissive sections, and an illumination component 200 is positioned on the opposite side and focuses the second of the transparent or transmissive sections. The illumination component 200 is configured to provide sufficient light to facilitate visualization of particles in the processing channel 192 by the visualization component 198.

[0129] In certain embodiments, particle isolation devices of the present invention also include a tapered inlet port. As illustrated in FIG. 22A , a prior art fluidic device includes a fluid input port 202 leading to a fluid channel 204. The dotted line 206 in FIG. 22A illustrates the fluid flow vectors within a prior art non-tapered inlet port. In such devices, vortices are generated at the entrance to the fluid channel 204. These vortices can reduce the efficiency or rate of sample processing by providing a location where cells or other particles can become trapped in a circulating path rather than flowing through the device. The vortex flow can also induce shear stress on particles, such as cells. According to an embodiment of the present invention as illustrated in FIG. 22B , the fluid input port 202 includes a tapered transition 210 into the fluid channel 204. The tapered transition substantially eliminates vortices and results in a smoother, laminar fluid flow into the fluid channel 204, as represented by the dotted vector line 208.

[0130] Further additional components may include a microplate holder, which may include a component with a receptacle for holding one or more outlet collection tubes, a receptacle for holding one or more input tubes, a receptacle for one or more temperature-controlled tubes, e.g., a cryoplate storing one or more outlet tubes at a temperature approaching 4 degrees Celsius, or positioning means for coupling an inlet or outlet to a well in a microplate. The device may also be integrated with a microprocessor or computer programmed to record, analyze, and / or control fluid and / or particle flow and separation through the device. IV. Methods for Isolating Particles

[0131] According to the method of the present invention, particles may be isolated using the device described hereinabove. Numerous applications require particle isolation, including applications requiring the separation of similar particles from other particles, particle identification, and particle treatment or other manipulation. Such applications include, but are not limited to, separating live and dead cells, isolating and / or treating circulating tumor cells, emulsion PCR enrichment, isolating circulating fetal cells, producing plasma such as platelet-rich plasma, isolating sperm for specific characteristics such as sex selection, bacterial load testing, antibiotic resistance testing, identifying sepsis or blood contamination, immune cell isolation, compound screening, exosome isolation, or extracellular vesicle isolation. The particle isolation method of the present invention may be utilized in any of these applications.

[0132] According to the method of the present invention, a substance containing particles of interest is combined with a paramagnetic medium to produce a treatment solution. The paramagnetic medium includes a paramagnetic material and a solvent. According to a preferred embodiment, the paramagnetic medium is biocompatible, i.e., capable of being mixed with living cells and not affecting cell viability or cell behavior, e.g., gene expression. The paramagnetic material may be selected from the group including gadolinium, titanium, vanadium, dysprosium, chromium, manganese, iron, nickel, and gallium, including ions thereof and combinations thereof. According to certain embodiments, the paramagnetic material is selected from the group including titanium(III) ions, gadolinium(III) ions, vanadium(I) ions, nickel(II) ions, chromium(III) ions, vanadium(III) ions, dysprosium(III) ions, cobalt(II) ions, and gallium(III) ions. According to a preferred embodiment, the paramagnetic material includes a chelate compound. According to preferred embodiments, the paramagnetic material comprises a gadolinium chelate, a dysprosium chelate, or a manganese chelate. According to certain embodiments, the paramagnetic medium comprises a paramagnetic material, salts, and other additives that function to maintain cellular integrity.

[0133] According to certain embodiments, the paramagnetic material may be present in the paramagnetic medium at a concentration of at least about 10 mM, 20 mM, 30 mM, 40 mM, 50 mM, 60 mM, 70 mM, 80 mM, 90 mM, 100 mM, 120 mM, 150 mM, 200 mM, 250 mM, 300 mM, 500 mM, or 1 M. According to certain embodiments, the paramagnetic material may be present in the paramagnetic medium at a concentration of about 10 mM to about 50 mM, about 25 mM to about 75 mM, about 50 mM to about 100 mM, about 100 mM to about 150 mM, about 150 mM to about 200 mM, about 200 mM to about 250 mM, about 250 mM to about 300 mM, about 300 mM to about 500 mM, or about 500 mM to about 1 M.

[0134] In some embodiments, the paramagnetic material comprises gadolinium and is present in the paramagnetic medium at a concentration of at least about 10 mM, 20 mM, 30 mM, 40 mM, 50 mM, 60 mM, 70 mM, 80 mM, 90 mM, or 100 mM. In some embodiments, the paramagnetic material comprises gadolinium and is present in the paramagnetic medium at a concentration of about 10 mM to about 50 mM, about 25 mM to about 75 mM, or about 50 mM to about 100 mM.

[0135] A processing solution is injected into an inlet port of the particle isolation device and flows through a fluid channel structure into the processing channel. The processing channel comprises a generally linear fluid channel flanked on either side by an upper magnetic component and a lower magnetic component. As the processing fluid passes through the fluid channel in the processing channel, the processing fluid is exposed to an asymmetric magnetic field generated by the upper and lower magnetic components. The exact configuration of magnetic components used in the method is predetermined based on the density of the particles of interest relative to the density of the paramagnetic medium. If the particles of interest are denser than the paramagnetic medium, a magnetic component configuration is selected in which the magnetic force exerted by the lower magnetic component is greater than the magnetic force exerted by the upper magnetic component. Conversely, if the paramagnetic medium is denser than the particles of interest, a magnetic component configuration is selected in which the magnetic force exerted by the upper magnetic component is greater than the magnetic force exerted by the lower magnetic component.

[0136] As the processing fluid passes through the asymmetric magnetic field in the processing channel, the particles of interest will reach substantially similar equilibrium altitudes. According to embodiments of the method of the present invention, substantially all of the particles of interest contained within the processing fluid will reach an equilibrium altitude, defined as the vertical component of the particle position at which the particle remains stationary under zero fluid flow rate conditions. The equilibrium altitudes range from less than 35% of the vertical gap between the upper and lower magnets (see, e.g., vertical gap 52 shown in FIG. 6 ), less than 30% of the vertical gap between the upper and lower magnets, less than 25% of the vertical gap between the upper and lower magnets, less than 20% of the vertical gap between the upper and lower magnets, less than 15% of the vertical gap between the upper and lower magnets, less than 10% of the vertical gap between the upper and lower magnets, less than 8% of the vertical gap between the upper and lower magnets, less than 6% of the vertical gap between the upper and lower magnets, or less than 5% of the vertical gap between the upper and lower magnets. According to embodiments of the methods of the present invention, at least about 70%, 75%, 80%, 85%, 90%, or 95% of the particles of interest contained within the treatment fluid will reach an equilibrium altitude ranging from less than 35% of the vertical gap between the upper and lower magnets, less than 30% of the vertical gap between the upper and lower magnets, less than 25% of the vertical gap between the upper and lower magnets, less than 20% of the vertical gap between the upper and lower magnets, less than 15% of the vertical gap between the upper and lower magnets, less than 10% of the vertical gap between the upper and lower magnets, less than 8% of the vertical gap between the upper and lower magnets, less than 6% of the vertical gap between the upper and lower magnets, or less than 5% of the vertical gap between the upper and lower magnets.

[0137] The equilibrium altitude of levitated particles between the magnets can be considered in terms of the percentage of altitude from the top surface of the bottom magnet to the bottom surface of the top magnet. The equilibrium altitude can be expressed as a percentage of this altitude or "relative altitude," where 0% relative altitude is at the bottom magnet, 100% relative altitude is at the top magnet, and 50% is at an altitude vertically centered between the magnets. According to certain embodiments of the invention, the equilibrium relative altitude distribution of substantially all particles of interest contained within the processing fluid will vary by no more than about 35%, or about 30%, or about 25%, or about 20%, or about 15%, or about 10%, or about 5%. According to certain embodiments of the present invention, the equilibrium relative height distribution of at least about 70%, 75%, 80%, 85%, 90%, or 95% of the particles of interest contained within the treatment fluid will vary by no more than about 35%, or about 30%, or about 25%, or about 20%, or about 15%, or about 10%, or about 5%.

[0138] Once the particles of interest reach their equilibrium altitude, they pass through a splitter that geometrically divides the processing solution into multiple fractions. Because the particles of interest are geometrically isolated within the processing solution, substantially all of the particles of interest are retained within the outflow of a certain geometric fraction. One or more geometric outflow fractions containing the particles of interest are then collected and recombined if the particles of interest are present in more than one fraction, thereby isolating the particles of interest. In some embodiments, it may be necessary to separate cells from the paramagnetic medium. This may be accomplished through dilution if separation of cells from the paramagnetic medium is desired.

[0139] Alternatively, the division of the processing solution into each output fraction can be achieved by increasing or decreasing the fluid flow toward the individual outlets, so that the ratio of the division can be modified. According to certain embodiments, the ratio may be modified by up to 50%. For example, if the splitter comprises two channels with equal cross-sections, the geometric ratio of the division is 1:1. By drawing a larger (or smaller) amount of fluid into one fraction through application of a larger (or smaller) pumping rate than that applied to the other fraction, the ratio of the division can be altered to, for example, about 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1. In preferred embodiments, the division with respect to such a geometric ratio will be in the range of about 2:1 to about 1:2. V. The Disclosed Embodiments are Non-Limiting

[0140] While various embodiments of the present invention have been shown and described herein, it is emphasized that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may be made in the various embodiments thereof without departing from the invention herein. Specifically, when any range is set forth herein, unless expressly stated otherwise, that range includes all values ​​therein and all subranges therein.

[0141] Also, more generally, in accordance with the disclosure, discussion, examples, and embodiments herein, conventional fluidics, molecular biology, cell biology, microbiology, and recombinant DNA techniques within the art may be employed. Such techniques are fully explained in the literature. (See, e.g., Sambrook and Russell, "Molecular Cloning: A Laboratory Manual," Third Edition 2001 (volumes 1-3), Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY; Animal Cell Culture, RI Freshney, ed., 1986.) These published resources are incorporated herein by reference for their particular teachings of standard laboratory methods found therein. Such incorporation shall be for, at a minimum, the specific teachings and / or other purposes that may be described when citing the reference herein. If specific teachings and / or other purposes are not so described, the published resource is specifically incorporated for the teachings indicated by one or more of the title, abstract, and / or summary of the reference. In cases where such specifically identified teachings and / or other purposes may not be so relevant, the public resources are incorporated to more fully describe the state of the art to which the present invention pertains and / or to provide such teachings as may be applicable and generally known to those skilled in the art. However, it is specifically stated that citation of public resources herein shall not be construed as an admission that such is prior art to the present invention. Also, in the event that one or more of the incorporated public resources differs from or conflicts with the present application, including, but not limited to, defined terms, term usage, described techniques, or equivalents, the present application shall control as the preferred embodiment, and any conflict may be deemed to be the alternative embodiment. Subject matter in the examples is incorporated into this section to the extent not preexisting. [Example]

[0142] A device according to the present invention was used to separate polymer beads, simulating particles of interest such as cells and other particles described hereinabove. The device used in this experiment included an oval channel that was 80 mm long and 1.78 mm high. Neodymium magnets were positioned above and below the channel, with the bottom magnet resting on the channel and a vertical separation between the channel and the upper magnet of approximately 400 microns. The upper magnet was 5 mm high. The lower magnet was 10 mm high and included a stack of two magnets, each 5 mm high. The bead and gadobutrol mixture was pushed into the capillary using a single syringe positioned on the inlet side of the capillary.

[0143] Approximately equal amounts of three groups of polymer beads with three different densities were mixed together. The beads included beads with densities of 1.091 g / cc, 1.014 g / cc, and 1.05 g / cc and corresponding diameters of 35 microns, 35 microns, and 10 microns, respectively. The mixed beads were combined with a 100 mM solution of gadobutrol in 1x phosphate-buffered saline (PBS). The bead / gadobutrol fluid mixture was injected into the device's channels. As the mixture flowed through the channels, it was exposed to a magnetic field exerted by a magnet, and the three types of beads responded differently by levitating to different altitudes.

[0144] The results are shown in Figures 23 and 24. Figure 23 is an image of the beads as they were passed through the magnetic field, and the separation of the three types of beads is clearly visible. Figure 24 is a graph showing the height distribution of the various beads, again illustrating the clear separation of the beads.

[0145] While preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It will be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention.

Claims

[Claim 1] The invention described in this specification.

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