System and method for extraction of paramagnetic or diamagnetic particles of different types from a fluid

Abstract

The invention relates to an extraction system (110) for extraction of paramagnetic or diamagnetic particles (112) of different types from a fluid (114), the system (110) comprising: - at least one magnetic field generator (116) configured for generating a magnetic field having a magnetic field gradient along a z-axis; - at least one flow channel (120) configured for guiding the fluid (114) comprising the particles (112) into the magnetic field essentially along the z-axis, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on the at least one particle; wherein the extraction system (110) comprises at least one extraction unit (122) configured for extracting the particles (112) of different types from the fluid (114), wherein the at least one extraction unit (122) comprises at least one extractor coil (124) configured for generating at least one further magnetic field having a further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis. The invention further relates to a method for extraction of paramagnetic or diamagnetic particles (112) of different types from a fluid (114).

Description

Technical Field

[0001] The invention relates to an extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid and a method for extraction of paramagnetic or diamagnetic particles of different types from a fluid.

[0002] The systems and methods according to the present invention specifically may be employed for example in the technical field of separation, extraction and purification technologies, particularly focusing on improving downstream processing in the biopharmaceutical industry, medical and biological analyses, 3D cell culture and solvent purification. Additionally, the invention may be applicable to the separation, extraction and analysis of substances in fluids, such as blood, for medical and biological purposes, as well as in the controlled synthesis of crystals and molecules.Background art

[0003] GB2482658A discloses a non-linear magnetophoresis system for separating particles within a sample comprising a magnetophoresis chip having an inlet for introducing a sample flow and a flow path comprising a first fluid path and a second fluid path in fluent communication with each other, wherein a magnetic array is in proximity of the first fluid path in such a way that the sample flowing along the flow path is subjected to a magnetic field with particles that are attracted to the field being retained in the first fluid path whereas the remaining samples are being transported to the second fluid path. Preferably, the magnetic array is embedded in the first fluid path. The system may further comprise an external rotating magnetic field supplied by an electromagnet, means for controlling the flow rate through the chip, detection means, analysis means and collection means for the separated particles. Ideally the chip comprises two inlets, with one for a carrier fluid flow and one for sample flow, and at least two outlets, with one for each separated particle. By tuning an external magnet field frequency and the flow rate, the migration velocities of different particle types may be forced to differ by several orders of magnitude over an extended range of frequencies to allow for separation of particles.

[0004] WO 2012 / 115 100 A1 discloses a method and an apparatus which enable the separation of each of at least two kinds of particles from a mixture comprising the at least two kinds of particles continuously and with high accuracy using a gradient magnetic field, or enable the isolation of a particular kind of particles from the mixture using a gradient magnetic field. In the present invention, the mixture to be treated comprises at least two kinds of particles, wherein one kind of particles are made from a paramagnetic or diamagnetic material. A magnetic field of which the magnetic field gradient has a vertical component and a horizontal component is applied to a carrier liquid stored in a separation vessel. Upon the addition of the mixture to the carrier liquid, the one kind of particles are guided so as to be located at a predetermined height from the bottom surface of the separation vessel in the carrier solution while migrating in the horizontal direction. Alternatively, the one kind of particles float magnetically on the liquid surface of the carrier solution and migrate in the horizontal direction. Another kind of particles among the at least two kinds of particles are located at a position that is different from that of the one kind of particles in the vertical direction between the bottom surface of the separation vessel and the liquid surface of the carrier solution.

[0005] KR 100 791 036 B1 discloses a method for separation of pure carbon nanotubes from carbon nanotubes containing metal impurities using continuous magnetophoresis comprising: a first step of injecting carbon nanotube fluid samples before purification into an injection part; a second step of injecting a control fluid into a control fluid injection part to flow the injected carbon nanotube fluid samples through central parts of microfluidic channels in a state that the injected carbon nanotube fluid samples are aligned; a third step of applying a flux density gradient perpendicularly to the microfluidic channels having the control fluid comprising the carbon nanotube fluid samples passed therethrough to separate pure carbon nanotubes from carbon nanotubes containing metal impurities; and a fourth step of capturing the pure carbon nanotubes that have been separated from the carbon nanotubes containing metal impurities through the microfluidic channels of the third step at discharge parts in which branch roads are formed at ends of the microfluidic channels.

[0006] US 10 253 309 B2 discloses an apparatus for separating fine particles using magnetophoresis, and a method for separating fine particles using same, and particularly, an apparatus for separating fine particles using magnetophoresis, which includes a fine, patterned magnetic structure capable of quickly and efficiently separating even particles that are weakly magnetized and coupled to fine particles, and a method for separating fine particles using same.

[0007] WO2009006409 A2 discloses the ability to levitate, to separate, and to detect changes in density using diamagnetic particles suspended in solutions containing paramagnetic cations using an inhomogeneous magnetic field. The major advantages of this separation device are that: i) it is a simple apparatus that does not require electric power (a set of permanent magnets and gravity are sufficient for the diamagnetic separation and collection system to work); ii) it is compatible with simple optical detection (provided that transparent materials are used to fabricate the containers / channels where separation occurs; iii) it is simple to collect the separated particles for further processing; iv) it does not require magnetic labeling of the particles / materials; and v) it is small, portable. The method and kits provided provide for separation and collection of materials of different densities, diagnostics for detection of analytes of interest, monitoring of solid-supported chemical reactions and determination of densities of solid and liquid mixtures.

[0008] WO 2017 / 059 353 A1 discloses systems and methods for levitating populations of moieties, cells, or other such units using one or more magnets in a microfluidic environment. These systems and methods may be used to, for example, separate or sort heterogeneous populations of the units from one another, to assembly a multi-unit assembly during the levitating of the units, and to evaluate samples at the point of care in real-time. These systems and methods may also utilize a frame that enables an imaging device, such as a smartphone, to capture the units in real time as they are manipulated in the system.

[0009] Shencheng Ge et al. describe in Magnetic Levitation in Chemistry, Materials Science, and Biochemistry, Angew. Chem. Int. Ed. 2020, 59, 17810-17855 that all matter has density. Today, measurements of density are used to separate and characterize a range of materials (including cells and organisms), and their chemical and / or physical changes in time and space. They describe a density-based technique - magnetic levitation (called "MagLev" for simplicity) - developed and used to solve problems in the fields of chemistry, materials science, and biochemistry. MagLev has two principal characteristics - simplicity, and applicability to a wide range of materials - that make it useful for a number of applications (for example, characterization of materials, quality control of manufactured plastic parts, self-assembly of objects in 3D, separation of different types of biological cells, and bioanalyses).

[0010] Its simplicity and breadth of applications also enable its use in low resource settings (for example - in economically developing regions - in evaluating water / food quality, and in diagnosing disease).Problem to be solved

[0011] It is therefore desirable to provide an extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid and a method for extraction of paramagnetic or diamagnetic particles of different types from a fluid, which at least partially address the above-mentioned technical challenges and at least substantially avoid the disadvantages of known methods and devices.

[0012] It may be desirable to provide an extraction system and a method that are efficient, cost-effective and automatable. Further, it may be desirable to enhance the yield, reduce the costs and time as well as intensify and reduce the footprint of the processes associated with downstream processing.Summary

[0013] This problem is addressed by an extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid and a method for extraction of paramagnetic or diamagnetic particles of different types from a fluid with the features of the independent claims. Advantageous embodiments which might be realized in an isolated fashion or in any arbitrary combinations are listed in the dependent claims as well as throughout the specification.

[0014] In a first aspect, an extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid is disclosed. For this aspect, reference may be made to any definition, embodiment and / or further aspect as disclosed elsewhere herein.

[0015] The term "extraction system" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary system configured for extracting particles from a fluid. In order to be able to extract the particles, the system may further be configured for separating the particles within the fluid. Said separation may be particle type specific, particularly in a manner that a specific type of particles may be accumulated at a specific position within the fluid. Particles of a differing type may be forced at positions differing from the specific position. The accumulated particles of the specific type may be extracted. Consequently, the extraction may be type specific. Particularly a specific type of particles may be extracted from the fluid while a different type of particle remains in the fluid or are extracted from the fluid at a differing specific position.

[0016] The term "extraction" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the process of separating at least one specific particle from a fluid. Extraction may comprise utilizing physical forces, such as a further magnetophoretic force, to achieve the isolation of the specific particles from the rest of the fluid. The goal of the extraction process is to selectively remove the specific particles from the fluid while leaving the rest of the fluid and any unwanted further particles behind.

[0017] The term "type of particle" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a particular particle showing specific physical characteristic making it possible to distinguish particular particles of a specific type from further particles of a differing type. A specific physical characteristic may be a physical characteristic that influences a direction and / or a strength a magnetophoretic force acts on the particular particle. Such a physical characteristic may be at least one of: a magnetic property, preferably the magnetic susceptibility of the particular particle, a volume of the particle, a shape of the particle, one or more dimensions of the particle, the surface characteristics of the particles, the chemical or mechanical interaction of the surface of the particle with the fluid, the surface energy of the particle, the tendency to agglomerate with other particles and others. The magnetic property may depend on the fluid that carries the particular particle. A further specific physical characteristics may be a physical characteristics that influences a direction and / or a strength a drag force acts on the particular particle. Said physical characteristics may be at least one of: a volume of the particle, a roughness of the particle, the surface characteristics of the particle, the chemical or mechanical interaction of the surface of the particle with the fluid, the surface energy of the particle, the tendency to agglomerate with other particles.

[0018] The person skilled in the art may notice that further forces may act on a specific particle, such as gravity, also referred to as the force of gravity, which may act on the particular particle, and the buoyant force, which may act on the particular particle when being in the fluid. Although said forces initially play a minor role, they may still be utilized to separate particles from one another. Consequently, further specific physical characteristics may be related to the force of gravity and / or the buoyancy force.

[0019] The extraction system comprises: at least one magnetic field generator configured for generating a magnetic field having a magnetic field gradient along the z-axis; at least one flow channel configured for guiding the fluid comprising the particles into the magnetic field essentially along the z-axis, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on at least one particle; wherein the extraction system comprises at least one extraction unit configured for extracting the particles of different types from the fluid comprises at least one extractor coil configured for generating at least one further magnetic field having a further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis.

[0020] The term "magnetic field generator" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to device or assembly configured to generate a magnetic field in a specified region of space. The magnetic field generator may be configured for generating a non-uniform magnetic field, wherein the strength and / or direction of the non-uniform magnetic field varies across the specified region of space. In that manner the magnetic field generator may be configured for generating a magnetic field gradient.

[0021] Of particular interest for the present invention may be a magnetic field gradient that is generated along the z-axis. Typically, the magnetic field generator may be configured for generating a magnetic field gradient along a z-axis.

[0022] At least one magnetic field generator may be rotationally symmetrical with respect to the z-axis. At least one magnetic field generated by the magnetic field generator may be rotationally symmetrical with respect to the z-axis.

[0023] The magnetic field generated by the magnetic field generator may be at least partially electrically induced, particularly in a manner that the magnetic field gradient along the z-axis can be adjusted electrically. The term "electrically induced" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a process that is initiated or caused by the application of an electric current and / or an electric voltage. In the context of magnetic fields, for example, an electrically induced magnetic field may be a magnetic field that is generated by passing an electric current through the magnetic field generator.

[0024] The term "adjusting" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the process of setting at least one parameter to generate a particular state or a particular outcome. In case of the present disclosure, the magnetic field gradient and / or the flow rate may be adjusted. Consequently, the magnetic field gradient and / or the flow rate may be set, particularly to a predetermined or known control parameter. The predetermined or known control parameter may be derived in a factory calibration procedure, a calibration procedure and / or in an experiment / sample-related procedure.

[0025] The magnetic field generator comprises at least one of: a superconducting coil; a normal conducting coil; a permanent magnet. The term "normal conducting coil" may refer to a coil made from materials that exhibit standard electrical conductivity, as opposed to superconducting materials.

[0026] The term "flow channel" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a pathway or conduit through which a fluid may be directed to flow, thereby guiding the movement of the fluid in a controlled manner.

[0027] The flow channel may be configured to guide the fluid into and / or through the magnetic field. Consequently, the flow channel may be configured to pass into or through the magnetic field. The at least one magnetic field generator, or elements of the magnetic field generator, may be arranged, at least in part, around the flow channel, preferably symmetrically around the flow channel.

[0028] The flow channel may be configured to guide the fluid into the magnetic field such that a main flow direction of the guided fluid is essentially parallel and / or essentially coaxial to the magnetic field gradient along a z-axis. The flow channel may comprise a central axis that is essentially parallel and / or essentially coaxial to the magnetic field gradient along a z-axis.

[0029] The term "essentially" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a maximum deviation from a specific value, preferably of 20°, 15°, 10°, 5°, 3°, 2° or 1°. "Essentially along the z-axis" may refer to being parallel and / or coaxial to the z-axis with a maximum deviation thereof of 20°, 15°, 10°, 5°, 3°, 2° or 1°.

[0030] For example , the at least one magnetic field generator may comprise at least one opening, wherein the at least one flow channel may be configured for guiding the fluid comprising the particles into the magnetic field through the opening of the at least one magnetic field generator.

[0031] In a separation phase, o a flow rate of the fluid being guided into the magnetic field may be adjusted; and / or o the magnetic field gradient along the z-axis of the at least one magnetic field generator may be adjusted; preferably by using a control unit, in a manner that at least the magnetophoretic force acting on particles and at least the drag force exerted by the flowing fluid acting on particles balance each other in a manner that particles of a specific type are held at a specific position along the z-axis.

[0032] As already indicated, the extraction system comprises the at least one extraction unit configured for extracting the particles of different types from the fluid, wherein the at least one extraction unit comprises the at least one extractor coil configured for generating the at least one further magnetic field having the further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis.

[0033] Thereby, a further magnetophoretic force induced by the further magnetic field gradient generated by the at least one extractor coil may act on the particles of the specific type held at the specific position along the z-axis in a manner that the at least one particle drifts out of the fluid, in an extraction phase. Particles of any further specific type that is different from the specific type may not be held at the specific position and may, therefore, not be extracted from the fluid. During the extraction phase, the flow rate of the fluid being guided into the magnetic field may remain constant; and the magnetic field gradient along the z-axis of the at least one magnetic field generator may remain constant.

[0034] The term "extraction unit" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a device comprising at least one extractor coil configured for generating the further magnetic field gradient in a tunable manner. The at least one extractor coil may be configured to generate no further magnetic field gradient when the particles of the specific type are not held at the specific position along the z-axis. The at least one extractor coil may be configured to generate the further magnetic field gradient when the particles of the specific type are held at the specific position along the z-axis. Consequently, the at least one extractor coil may be configured to ramp up the further magnetic field gradient when the particles of the specific type are held at the specific position along the z-axis.

[0035] As already indicated, the further magnetic field gradient has a component that is orthogonal to the z-axis. The magnetic field gradient has a direction. Said direction may have a plurality of components, wherein each component is a projection of the direction of the magnetic field gradient on differing axes of a coordinate system. The term "component that is orthogonal to the z-axis" may refer to a specific projection on an axis that is orthogonal to the z-axis.

[0036] For the further magnetic field gradient to have a component that is orthogonal to the z-axis, at least one of: The direction of the further magnetic field gradient may be orthogonal to the z-axis. In this case, the component of the further magnetic field gradient that is orthogonal to the z-axis may be the only component of the further magnetic field gradient. The further magnetic field gradient may have the component that is orthogonal to the z-axis and the further magnetic field gradient may have a component that is parallel to the z-axis. Typically, the component that is orthogonal to the z-axis may be larger than the component that is parallel to the z-axis gradient, such as 2, 5, 10 or 20 times larger.

[0037] In other words, the further magnetic field gradient may be essentially orthogonal to the z-axis. The further magnetic field gradient may be orthogonal to the z-axis a maximum deviation of 20°, 15°, 10°, 5°, 3°, 2° or 1°.

[0038] The disclosure, thereby, may address the need for more efficient, cost-effective and automated systems and methods for isolating and purifying desired products, such as particles, from complex mixtures. In the biopharmaceutical sector, the disclosure may seek to enhance the yield and reduce the costs associated with downstream processing, which is currently dominated by expensive and high-maintenance methods like chromatography.

[0039] The at least one extraction unit may further comprise at least one extraction channel. The at least one extraction channel may be configured for extracting particles from the flow channel. The at least one particle drifting out of the fluid may consequently drift through the at least one extraction channel out of the fluid. The at least one extraction channel may guide the at least one particle in a reservoir.

[0040] The at least one extraction unit may be or may comprise a plurality of extraction units, wherein each extraction unit of the plurality of extraction units is located at a different z-position on the z-axis. By using a plurality of extraction units at different z-position on the z-axis, a plurality of differing types of particles may be extracted from the fluid, specifically simultaneously.

[0041] Typically, the flow rate of the fluid being guided into and / or through the magnetic field may be independent of the z-position. Consequently, the flow rate may be constant at different z-positions. On the other hand, the flow rate may depend on the z-position, particularly in case a cross section of the at least one flow channel changes along the z-axes. The magnetic field gradient, specifically the strength of the magnetic field gradient may be different at different z-positions. As a result, for different types of particles, at least the drag force and at least the magnetophoretic force may balance at different specific z-positions depending on the types of the particles. Consequently, the plurality of different types of particles may be extracted from the fluid by the plurality of extraction units as the different types of particles are extracted at the different specific z-positions.

[0042] Alternatively or in addition, the at least one magnetic field generator may comprise two or more magnetic field generators, wherein each magnetic field generator of the two or more magnetic field generators generates a magnetic field having a different magnetic field strength, wherein the two or more magnetic field generators are spatially separated and each magnetic field generator of the two or more magnetic field generators is arranged at a different z-position on the z-axis. The at least one extraction unit may be arranged between two neighboring magnetic field generators of the two or more magnetic field generators in respect to the z-axis.

[0043] The at least one magnetic field generator may have a triangular outer shape. The triangular outer shape may allow generating a non-uniform magnetic field with varying strengths. Thereby, the magnetic field gradient may be generated in an easy and efficient manner.

[0044] The z-axis may be parallel to a direction of gravity, also referred to as force of gravity, with a maximum deviation thereof of 20°, 10°, 5°, 3° or 1°. When the z-axis is parallel to the direction of the force of gravity, the force of gravity and the buoyancy forces may act on the particles in the fluid along the z-axis. Consequently, when adjusting the flow rate of the fluid being guided into the magnetic field and / or adjusting the magnetic field gradient in a manner that particles of a specific type are held at a specific position along the z-axis, also the force of gravity and / or the buoyancy force may be balanced.

[0045] Typically, a drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field, or a magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles may be larger than the force of gravity, preferably at least 2 times larger, preferably 10 times larger. Therefore, the influence of the force of gravity may be small when compared to the drag force or the magnetophoretic force.

[0046] For the magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles to be larger than the force of gravity, the at least one magnetic field generator may be further configured for generating the magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles that is larger than the force of gravity.

[0047] The system may further comprise: at least one flow generating unit configured for generating a flow of the fluid through the flow channel in order to guide the fluid comprising the particles into the magnetic field.

[0048] The term "flow generating unit" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a device or an assembly configured to initiate and / or maintain the movement or flow of a fluid through a system or conduit. The flow generating unit may be or may comprise at least one kind of pump, such as a centrifugal, rotary, peristaltic or gravity pump, etc..

[0049] For the drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field to be larger than the force of gravity, the at least one flow inducing unit may be further configured for generating the drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field that is larger than the force of gravity.

[0050] The system may further comprise: at least one control unit configured for at least one of: o triggering the adjustment of a flow rate of the fluid being guided into the magnetic field, preferably by transmitting at least one control signal to the at least one flow generating unit; o triggering the adjustment of the magnetic field gradient along the z-axis of the at least one magnetic field generator, preferably by transmitting at least one further control signal to the at least one magnetic field generator; in a manner that at least the magnetophoretic force acting on particles and at least the drag force exerted by the flowing fluid acting on particles balance each other in a manner that particles of a specific type are held at a specific position along the z-axis.

[0051] The term "control unit" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a component configured to manage the operation of other devices or systems by processing input signals and generating appropriate output commands. The control unit may function as an open loop system. The control unit may be configured to use at least one predefined or known control parameter in order to adjust the flow rate and / or the magnetic field gradient. The control unit may be configured to select a specific at least one predefined control parameter depending on the fluid and / or the specific type of particle to be extracted and adjust the flow rate and / or the magnetic field gradient, accordingly. The predefined control parameter may be derived in a factory calibration procedure or calibrated based on the specific experiment or requirement.

[0052] As already indicated, the flow rate and / or the magnetic field gradient may be adjusted in a manner that particles of a specific type are held at a specific position along the z-axis. Therefore, the forces that are acting on the particles of a specific type may have to be balanced in a manner that the forces acting on the particles of a specific type negate each other, resulting in no net force acting on the particles of a specific type.

[0053] Typically, the following forces may act on the particles in the fluid: The magnetophoretic force F m = 2 πR 3 μ 0 μ r K ∇ H 2 , where F m represents the magnetophoretic force, H represents the magnetic field, R represents the radius of the particle, µ r represents the relative permeability of the fluid, µ r,p represents the relative permeability of the particle, and K is defined as K = μ r , p − μ r μ r , p + 2 μ r The direction of the magnetophoretic force depends on the magnetic properties of the particles. The drag force F d = 1 2 ρ v 2 CA , where F d represents the drag force, ρ represents the density of the fluid, v represents the flow velocity relative to the particle, C represents the drag coefficient and A represents the cross-sectional area of the particle. The force of gravity F g = Mg , where F g represents the gravity force, M represents the mass of the particle and g represents the acceleration due to gravity. The buoyancy force F b = V Δ pg , where F b represents the buoyancy force, V represents the volume of the particle, Δρ represents the mass density difference between the particle and the background fluid g represents the gravitational acceleration.

[0054] As already indicated, the flow rate and / or the magnetic field gradient may be adjusted. By doing so, the magnetophoretic force induced by the magnetic field gradient and the drag force may be adjusted in a manner that they negate each other. Consequently, a direction of the magnetophoretic force and a direction of the drag force may be opposite to each other. Further, an absolute value of the strength of the magnetophoretic force and an absolute value of the strength of the drag force may be equal to each other, particularly in case a strength of the force of gravity and / or a strength of the buoyancy force each are small compared to the strength of the magnetophoretic force and / or the strength of the drag force.

[0055] As already indicated, the z-axis may be parallel to the direction of the force of gravity. In this case, the z-axis may be further parallel to the buoyancy force. The force of gravity and the buoyancy force may then also be parallel to the magnetophoretic force and the drag force. When the flow rate and / or the magnetic field gradient are adjusted, the force of gravity and the buoyancy force may, in addition to the magnetophoretic force and the drag force, be balanced in a manner that all forces negate each other and the particles of the specific type are held at a specific position along the z-axis.

[0056] In summary, the flow rate and / or the magnetic field gradient may be adjusted in a manner that the magnetophoretic force and the drag force; the magnetophoretic force, the drag force and the force of gravity; the magnetophoretic force, the drag force and the buoyancy force; or the magnetophoretic force, the drag force, the force of gravity and the buoyancy force balance each other in a manner that the respective forces negate each other, resulting in no net force acting on the particle. Further forces acting on the particles may additionally be considered and negated. Since the forces may depend on physical characteristics of the particles, the forces, typically, balance for a specific type of particle. As a result, particles of a specific type are held at a specific position along the z-axis.

[0057] The fluid may be a liquid, preferably an aqueous solution comprising or containing one or more of: Manganese(II) chloride, MnCl2, Mangan(III)bromid, MnBr3, Copper(II) sulfate, CuSO4, Gadolinium(III) chloride, GdCl3, Dysprosium(III) chloride, DyCl3, Holmium(III) chloride, HoCl3, diethylenetriamine pentacetic acid, Gd-DTPA, a Gadolinium, GD, chelated compound, individually or in combination.

[0058] In a further aspect, a method for extraction of paramagnetic or diamagnetic particles of different types from a fluid is disclosed. For this aspect, reference may be made to any definition, Embodiment and / or further aspect as disclosed elsewhere herein.

[0059] The steps of the method may be performed in the given order. A different order, however, may also be feasible. Further, two or more of the method steps may be performed simultaneously. Thereby, the method steps may at least partly overlap in time. Further, the method steps may be performed once or repeatedly. Thus, one or more or even all of the method steps may be performed once or repeatedly. The method may comprise additional method steps, which are not listed herein.

[0060] The method comprising: flowing the fluid comprising the particles into a magnetic field having a magnetic field gradient along a z-axis by utilizing at least one flow channel, wherein the magnetic field gradient is generated by at least one magnetic field generator; in a separation phase, adjusting a flow rate of the fluid so that at least a magnetophoretic force acting on the particles and at least a drag force exerted by the flowing fluid acting on the particles balance each other in a manner that particles of a specific type are held at a specific z-position of the z-axis; in an extraction phase, applying an electric current to at least one extractor coil and, thereby, generating at least one further magnetic field having a further magnetic field gradient, preferably when the particles of the specific type are held at the specific z-position of the z-axis, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis, wherein the at least one extractor coil is comprised by at least one extraction unit.

[0061] The method step flowing the fluid into a magnetic field may be performed before the method step adjusting a flow rate of the fluid.

[0062] Consequently, the fluid may be flowing into the magnetic field at an arbitrary flow rate and then the flow rate may be adjusted.

[0063] The method steps flowing the fluid into a magnetic field and adjusting a flow rate of the fluid may be performed simultaneously. Alternatively, the method step adjusting a flow rate of the fluid may be performed before the method step flowing the fluid into a magnetic field.

[0064] Consequently, the fluid may be flowing into the magnetic field already with the adjusted flow rate.

[0065] During the separation phase the flow rate of the fluid may be adjusted. The adjusted flow rate may remain constant during the extraction phase.

[0066] The term "separation phase" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a specific stage in a process in which the particles in the fluid are spatially separated in a type specific manner based on the physical characteristics of the particles.

[0067] The term "extraction phase" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a stage in a process in which the particles are removed or isolated from the fluid.

[0068] The method may be performed by using an extraction system as elsewhere disclosed herein.

[0069] The method may further comprise: adjusting, in the separation phase, the magnetic field gradient along the z-axis of the at least one magnetic field generator for further balancing at least the magnetophoretic force acting on the particles and at least the drag force exerted by the flowing fluid acting on the particles in a manner that the particles of the specific type are held at the specific z-position on the z-axis.

[0070] For adjusting the magnetic field gradient along the z-axis of the at least one magnetic field generator, an electric current through at least one coil comprised by the at least one magnetic field generator may be adjusted.

[0071] The electric current through the at least one coil of the at least one magnetic field generator may be reduced during the extraction phase. The time required for the separation of the particles decreases when the flow rate increases. Since an increased flow rate is associated with stronger forces that can overcome the natural attractions holding the particles together, like Van der Waals forces or surface energy. However, when the flow rate increases, it also induces an increased drag force on the particles. Depending on the geometry and displacement of the parts of the system and the generated gradients, this increased drag force could push the particles closer together, reducing the margin of operability of the extraction system. In fact, as a result, the extraction channels used to extract the particles would need to be closer to each other, which may make the separation process less precise and harder to manage. By reducing the flow rate in a later stage, the particles could spread out more. This gives them more space between each other, making it easier to extract them effectively.

[0072] Particles of different types may be extracted in a step wise manner by adapting the drag force and / or the magnetophoretic force acting on the particles such that particles of different types are moved step wise to a z-position on the z-axis of the extraction unit, preferably at least one extraction channel of the extraction unit. The stepwise approach may help to ensure that each type of particle is isolated more effectively, reducing cross-contamination and improving the purity of the extracted particles.

[0073] As used in the following, the terms "have", "comprise" or "include" or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions "A has B", "A comprises B" and "A includes B" may both refer to a situation in which, besides B, no other element is present in A (i.e. a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements.

[0074] Further, it shall be noted that the terms "at least one", "one or more" or similar expressions indicating that a feature or element may be present once or more than once typically will be used only once when introducing the respective feature or element. In the following, in most cases, when referring to the respective feature or element, the expressions "at least one" or "one or more" will not be repeated, non-withstanding the fact that the respective feature or element may be present once or more than once.

[0075] Further, as used in the following, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features, without restricting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The invention may, as the skilled person will recognize, be performed by using alternative features. Similarly, features introduced by "in an embodiment of the invention" or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments of the invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention.

[0076] Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged: Embodiment 1: An extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid, the system comprising: at least one magnetic field generator configured for generating a magnetic field having a magnetic field gradient along a z-axis; at least one flow channel configured for guiding the fluid comprising the particles into the magnetic field essentially along the z-axis, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on the at least one particle; wherein the extraction system comprises at least one extraction unit configured for extracting the particles of different types from the fluid, wherein the at least one extraction unit comprises at least one extractor coil configured for generating at least one further magnetic field having a further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis. Embodiment 2: The extraction system according to the preceding Embodiment, wherein the at least one magnetic field generator comprises at least one opening, preferably wherein the opening is a central opening, wherein the at least one flow channel is configured for guiding the fluid comprising the particles into the magnetic field through the opening of the at least one magnetic field generator. Embodiment 3: The extraction system according to any one of the preceding Embodiments, wherein the at least one extraction unit further comprises at least one extraction channel, wherein the at least one extraction channel is configured for extracting particles from the flow channel. Embodiment 4: The extraction system according to the preceding Embodiments, wherein a further magnetophoretic force induced by the further magnetic field gradient generated by the at least one extractor coil acts on the at least one particle in a manner that the at least one particle drifts into the at least one extraction channel. Embodiment 5: The extraction system according to any one of the preceding Embodiments, wherein the at least one extraction unit is or comprises a plurality of extraction units, wherein each extraction unit of the plurality of extraction units is located at a different z-position on the z-axis. Embodiment 6: The extraction system according to any one of the preceding Embodiments, wherein the magnetic field generated by the magnetic field generator is at least partially electrically induced, particularly in a manner that the magnetic field gradient along the z-axis can be adjusted electrically. Embodiment 7: The extraction system according to any one of the preceding Embodiments, wherein the magnetic field generator comprises at least one of: a superconducting coil; a normal conducting coil; a permanent magnet. Embodiment 8: The extraction system according to any one of the preceding Embodiments, wherein the at least one magnetic field generator is rotationally symmetrical with respect to the z-axis. Embodiment 9: The extraction system according to any one of the preceding Embodiments, wherein the at least one magnetic field generator comprises two or more magnetic field generators, wherein each magnetic field generator of the two or more magnetic field generators generates a magnetic field having a different magnetic field strength, wherein the two or more magnetic field generators are spatially separated, wherein each magnetic field generator of the two or more magnetic field generators is arranged at a different z-position on the z-axis. Embodiment 10: The extraction system according to the preceding Embodiment, wherein the at least one extraction unit is arranged between two neighboring magnetic field generators of the two or more magnetic field generators in respect to the z-axis. Embodiment 11: The extraction system according to any one of the preceding Embodiments 1-8, wherein the at least one magnetic field generator has a triangular outer shape. Embodiment 12: The extraction system according to any one of the preceding Embodiments, wherein the z-axis is parallel to a direction of gravity with a maximum deviation thereof of 20°, 10°, 5°, 3° or 1°. Embodiment 13: The extraction system according to any one of the preceding Embodiments, wherein one of: a drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field, a magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles is larger than the force of gravity, preferably at least 2 times larger, preferably 10 times larger. Embodiment 14: The extraction system according to the preceding Embodiment, wherein, for the magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles to be larger than the force of gravity, the at least one magnetic field generator is further configured for generating the magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles that is larger than the force of gravity. Embodiment 15: The extraction system according to any one of the preceding Embodiments, the system further comprising: at least one flow generating unit configured for generating a flow of the fluid through the flow channel in order to guide the fluid comprising the particles into the magnetic field. Embodiment 16: The extraction system according to the preceding Embodiment, wherein, for the drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field to be larger than the force of gravity, the at least one flow inducing unit is further configured for generating the drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field that is larger than the force of gravity. Embodiment 17: The extraction system according to any one of the preceding Embodiments, the system further comprising: at least one control unit configured for at least one of: o triggering the adjustment of a flow rate of the fluid being guided into the magnetic field, preferably by transmitting at least one control signal to the at least one flow generating unit; o triggering the adjustment of the magnetic field gradient along the z-axis of the at least one magnetic field generator, preferably by transmitting at least one further control signal to the at least one magnetic field generator; in a manner that at least the magnetophoretic force acting on particles and at least the drag force exerted by the flowing fluid acting on particles balance each other in a manner that particles of a specific type are held at a specific position along the z-axis. Embodiment 18: The extraction system according to any one of the preceding Embodiments, wherein the fluid is a liquid, preferably an aqueous solution comprising or containing one or more of: Manganese(II) chloride, MnCl2, Mangan(III)bromid, MnBr3, Copper(II) sulfate, CuSO4, Gadolinium(III) chloride, GdCl3, Dysprosium(III) chloride, DyCl3, Holmium(III) chloride, HoCl3, diethylenetriamine pentacetic acid, Gd-DTPA, a Gadolinium, GD, chelated compound, individually or in combination. Embodiment 19: Method for extraction of paramagnetic or diamagnetic particles of different types from a fluid, the method comprising: flowing the fluid comprising the particles into a magnetic field having a magnetic field gradient along a z-axis by utilizing at least one flow channel, wherein the magnetic field gradient is generated by at least one magnetic field generator; in a separation phase, adjusting a flow rate of the fluid so that at least a magnetophoretic force acting on the particles and at least a drag force exerted by the flowing fluid acting on the particles balance each other in a manner that particles of a specific type are held at a specific z-position of the z-axis; in an extraction phase, applying an electric current to at least one extractor coil and, thereby, generating at least one further magnetic field having a further magnetic field gradient, preferably when the particles of the specific type are held at the specific z-position of the z-axis, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis, wherein the at least one extractor coil is comprised by at least one extraction unit. Embodiment 20: Method according to the preceding Embodiment, wherein the method is performed by using an extraction system according to any one of the preceding Embodiments referring to an extraction system. Embodiment 21: Method according to any one of the preceding method Embodiments, the method further comprising: adjusting, in the separation phase, the magnetic field gradient along the z-axis of the at least one magnetic field generator for further balancing at least the magnetophoretic force acting on the particles and at least the drag force exerted by the flowing fluid acting on the particles in a manner that the particles of the specific type are held at the specific z-position on the z-axis. Embodiment 22: Method according to the preceding Embodiment, wherein, for adjusting the magnetic field gradient along the z-axis of the at least one magnetic field generator, an electric current through at least one coil comprised by the at least one magnetic field generator is adjusted. Embodiment 23: Method according to the preceding method Embodiment, wherein the electric current through the at least one coil of the at least one magnetic field generator is reduced during the extraction phase. Embodiment 24: Method according to the preceding Embodiment, wherein particles of different types are extracted in a step wise manner by adapting the drag force and / or the magnetophoretic force acting on the particles such that particles of different types are moved step wise to a z-position on the z-axis of the extraction unit, preferably at least one extraction channel of the extraction unit. Short description of the Figures

[0077] Further optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features may be realized in an isolated fashion as well as in any arbitrary feasible combination, as the skilled person will realize. The scope of the invention is not restricted by the preferred embodiments. The embodiments are schematically depicted in the Figures. Therein, identical reference numbers in these Figures refer to identical or functionally comparable elements.

[0078] In the Figures: Figure 1shows an exemplary extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid; Figure 2shows a typically magnetic field generated by an exemplary magnetic field generator; Figure 3shows a typically flow rate field generated by a flow of the fluid in an exemplary flow channel; Figure 4shows a further typically magnetic field generated by a further exemplary magnetic field generator; and Figure 5shows an exemplary method for extraction of paramagnetic or diamagnetic particles of different types from a fluid. Detailed description of the embodiments

[0079] Figure 1 shows an exemplary extraction system 110 for extraction of paramagnetic or diamagnetic particles 112 of different types from a fluid 114. The fluid 114 and the particles 112 in the fluid 114 may be in a may be first reservoir 126.

[0080] The system 110 comprises: at least one magnetic field generator 116 configured for generating a magnetic field having a magnetic field gradient along a z-axis 118; at least one flow channel 120 configured for guiding the fluid 114 comprising the particles 112 into the magnetic field essentially along the z-axis 118, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on the at least one particle 112; wherein the extraction system 110 comprises at least one extraction unit 122 configured for extracting the particles 112 of different types from the fluid 114, wherein the at least one extraction unit 122 comprises at least one extractor coil 124 configured for generating at least one further magnetic field having a further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis 118.

[0081] The magnetic field generated by the magnetic field generator 116 may be at least partially electrically induced, particularly in a manner that the magnetic field gradient along the z-axis 118 can be adjusted electrically. The magnetic field generator 116 may comprise at least one of: a superconducting coil; a normal conducting coil; a permanent magnet.

[0082] The flow channel 120 may be comprised by a flow channel system 128. The flow channel system 128 may fluidically connect the first reservoir 126 and a second reservoir 130. The system 110 may further comprise: at least one flow generating unit 132 configured for generating a flow of the fluid 114 through the flow channel 120 in order to guide the fluid 114 comprising the particles 112 into the magnetic field.

[0083] The at least one flow generating unit 132 may be further configured for generating the flow in a manner that the fluid 114 and the particles 112 in the fluid 114 may flow from the first reservoir 126 into the second reservoir 126, particularly through the magnetic field.

[0084] The at least one magnetic field generator 116 may comprises at least one opening 134, preferably wherein the opening 134 is a central opening, wherein the at least one flow channel 120 is configured for guiding the fluid 114 comprising the particles 112 into the magnetic field through the opening 134 of the at least one magnetic field generator116. The at least one magnetic field generator 116 may be rotationally symmetrical with respect to the z-axis 118. The at least one magnetic field generator 116 may have a triangular outer shape.

[0085] The at least one extraction unit 122 further may comprise at least one extraction channel 136, wherein the at least one extraction channel 136 is configured for extracting particles 112 from the flow channel 120. Particularly therefore, a further magnetophoretic force induced by the further magnetic field gradient generated by the at least one extractor coil 124 acts on the at least one particle 112 in a manner that the at least one particle 112 drifts into the at least one extraction channel 136. The at least one particle 112 may drift through the at least one extraction channel 136 into at least one third reservoir 138.

[0086] The at least one extraction unit 122 is or comprises a plurality of extraction units 122, wherein each extraction unit 122 of the plurality of extraction units 122 is located at a different z-position on the z-axis 118. The plurality of extraction units 122 has a plurality of extraction channels 136, which may fed the extracted particles 112 into the same at least one third reservoirs 138 and / or differing at least one third reservoirs 138.

[0087] The system 110 further may comprise: at least one control unit 140 configured for at least one of: o triggering the adjustment of a flow rate of the fluid 114 being guided into the magnetic field, preferably by transmitting at least one control signal to the at least one flow generating unit 132; o triggering the adjustment of the magnetic field gradient along the z-axis 118 of the at least one magnetic field generator 116, preferably by transmitting at least one further control signal to the at least one magnetic field generator 116; in a manner that at least the magnetophoretic force acting on particles 112 and at least the drag force exerted by the flowing fluid 114 acting on particles 112 balance each other in a manner that particles 112 of a specific type are held at a specific position along the z-axis 118.

[0088] The z-axis 118 is parallel to a direction of gravity with a maximum deviation thereof of 20°, 10°, 5°, 3° or 1°. A drag force acting on the particles 112 that is exerted by the flowing fluid 114 being guided into the magnetic field or a magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles 112 may be larger than the force of gravity, preferably at least 2 times larger, preferably 10 times larger.

[0089] Figure 2 shows a typically magnetic field generated by an exemplary magnetic field generator 116. On the horizontal axis 142, a position on an axis orthogonal to the z-axis is indicated in Millimeter. On the vertical axis 144, a position on the z-axis is indicated in Millimeter. The curved lines indicate the magnetic flux of the magnetic field generated by the magnetic field generator 116.

[0090] Figure 3 shows a typically flow rate field generated by a flow of the fluid 114 in an exemplary flow channel 120. On the horizontal axis 146, a position on an axis orthogonal to the z-axis is indicated in Millimeter. On the vertical axis 148, a position on the z-axis is indicated in Millimeter. The arrows indicate the velocity of the flow of the fluid 114.

[0091] Figure 4 shows a further typically magnetic field generated by a further exemplary magnetic field generator 116. On the horizontal axis 150, a position on an axis orthogonal to the z-axis is indicated in Millimeter. On the vertical axis 152, a position on the z-axis is indicated in Millimeter. The curved lines indicate the magnetic flux of the magnetic field generated by the magnetic field generator 116.

[0092] As may be derived from Figure 4, the at least one magnetic field generator 116 may comprises two or more magnetic field generators 116, wherein each magnetic field generator 116 of the two or more magnetic field generators 116 generates a magnetic field having a different magnetic field strength, wherein the two or more magnetic field generators 116 are spatially separated, wherein each magnetic field generator 116 of the two or more magnetic field generators 116 is arranged at a different z-position on the z-axis. The at least one extraction unit 122 may be arranged between two neighboring magnetic field generators 116 of the two or more magnetic field generators 116 in respect to the z-axis.

[0093] Figure 5 shows an exemplary method 154 for extraction of paramagnetic or diamagnetic particles 112 of different types from a fluid 114. The method 154 comprises: (denoted by reference number 156) flowing the fluid 114 comprising the particles 112 into a magnetic field having a magnetic field gradient along a z-axis by utilizing at least one flow channel 120, wherein the magnetic field gradient is generated by at least one magnetic field generator 116; (denoted by reference number 158) in a separation phase, adjusting a flow rate of the fluid 114 so that at least a magnetophoretic force acting on the particles 112 and at least a drag force exerted by the flowing fluid 114 acting on the particles 112 balance each other in a manner that particles 112 of a specific type are held at a specific z-position of the z-axis; (denoted by reference number 160) in an extraction phase, applying an electric current to at least one extractor coil 124 and, thereby, generating at least one further magnetic field having a further magnetic field gradient, preferably when the particles 112 of the specific type are held at the specific z-position of the z-axis, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis, wherein the at least one extractor coil 124 is comprised by at least one extraction unit 122.

[0094] The method further may comprise: (denoted by reference number 162) adjusting, in the separation phase, the magnetic field gradient along the z-axis of the at least one magnetic field generator 116 for further balancing at least the magnetophoretic force acting on the particles 112 and at least the drag force exerted by the flowing fluid 114 acting on the particles 112 in a manner that the particles 112 of the specific type are held at the specific z-position on the z-axis.

[0095] For adjusting the magnetic field gradient along the z-axis of the at least one magnetic field generator 116 (denoted by reference number 162), an electric current through at least one coil comprised by the at least one magnetic field generator 116 is adjusted.

[0096] The electric current through the at least one coil of the at least one magnetic field generator 116 is reduced during the extraction phase.

[0097] Particles 112 of different types may be extracted in a step wise manner by adapting the drag force and / or the magnetophoretic force acting on the particles 112 such that particles 112 of different types are moved step wise to a z-position on the z-axis of the extraction unit 122, preferably to at least one extraction channel of the extraction unit 122.List of reference numbers

[0098] 110extraction system 112paramagnetic or diamagnetic particle 114fluid 116magnetic field generator 118z-axis 120flow channel 122extraction unit 124extractor coil 126first reservoir 128flow channel system 130second reservoir 132flow generating unit 134opening 136extraction channel 138third reservoir 140control unit 142horizontal axis 144vertical axis 146horizontal axis 148vertical axis 150horizontal axis 152vertical axis 154method for extraction of paramagnetic or diamagnetic particles of different types from a fluid 156flowing the fluid comprising the particles into a magnetic field 158adjusting a flow rate of the fluid 160applying an electric current to at least one extractor coil 162adjusting the magnetic field gradient along the z-axis

Examples

Embodiment Construction

[0079]Figure 1 shows an exemplary extraction system 110 for extraction of paramagnetic or diamagnetic particles 112 of different types from a fluid 114. The fluid 114 and the particles 112 in the fluid 114 may be in a may be first reservoir 126.

[0080]The system 110 comprises:

at least one magnetic field generator 116 configured for generating a magnetic field having a magnetic field gradient along a z-axis 118; at least one flow channel 120 configured for guiding the fluid 114 comprising the particles 112 into the magnetic field essentially along the z-axis 118, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on the at least one particle 112;

wherein the extraction system 110 comprises at least one extraction unit 122 configured for extracting the particles 112 of different types from the fluid 114, wherein the at least one extraction unit 122 comprises at least one extractor coil 124 configured for generating at least one further ma...

Technical Field

[0001] The invention relates to an extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid and a method for extraction of paramagnetic or diamagnetic particles of different types from a fluid.

[0002] The systems and methods according to the present invention specifically may be employed for example in the technical field of separation, extraction and purification technologies, particularly focusing on improving downstream processing in the biopharmaceutical industry, medical and biological analyses, 3D cell culture and solvent purification. Additionally, the invention may be applicable to the separation, extraction and analysis of substances in fluids, such as blood, for medical and biological purposes, as well as in the controlled synthesis of crystals and molecules.Background art

[0003] GB2482658A discloses a non-linear magnetophoresis system for separating particles within a sample comprising a magnetophoresis chip having an inlet for introducing a sample flow and a flow path comprising a first fluid path and a second fluid path in fluent communication with each other, wherein a magnetic array is in proximity of the first fluid path in such a way that the sample flowing along the flow path is subjected to a magnetic field with particles that are attracted to the field being retained in the first fluid path whereas the remaining samples are being transported to the second fluid path. Preferably, the magnetic array is embedded in the first fluid path. The system may further comprise an external rotating magnetic field supplied by an electromagnet, means for controlling the flow rate through the chip, detection means, analysis means and collection means for the separated particles. Ideally the chip comprises two inlets, with one for a carrier fluid flow and one for sample flow, and at least two outlets, with one for each separated particle. By tuning an external magnet field frequency and the flow rate, the migration velocities of different particle types may be forced to differ by several orders of magnitude over an extended range of frequencies to allow for separation of particles.

[0004] WO 2012 / 115 100 A1 discloses a method and an apparatus which enable the separation of each of at least two kinds of particles from a mixture comprising the at least two kinds of particles continuously and with high accuracy using a gradient magnetic field, or enable the isolation of a particular kind of particles from the mixture using a gradient magnetic field. In the present invention, the mixture to be treated comprises at least two kinds of particles, wherein one kind of particles are made from a paramagnetic or diamagnetic material. A magnetic field of which the magnetic field gradient has a vertical component and a horizontal component is applied to a carrier liquid stored in a separation vessel. Upon the addition of the mixture to the carrier liquid, the one kind of particles are guided so as to be located at a predetermined height from the bottom surface of the separation vessel in the carrier solution while migrating in the horizontal direction. Alternatively, the one kind of particles float magnetically on the liquid surface of the carrier solution and migrate in the horizontal direction. Another kind of particles among the at least two kinds of particles are located at a position that is different from that of the one kind of particles in the vertical direction between the bottom surface of the separation vessel and the liquid surface of the carrier solution.

[0005] KR 100 791 036 B1 discloses a method for separation of pure carbon nanotubes from carbon nanotubes containing metal impurities using continuous magnetophoresis comprising: a first step of injecting carbon nanotube fluid samples before purification into an injection part; a second step of injecting a control fluid into a control fluid injection part to flow the injected carbon nanotube fluid samples through central parts of microfluidic channels in a state that the injected carbon nanotube fluid samples are aligned; a third step of applying a flux density gradient perpendicularly to the microfluidic channels having the control fluid comprising the carbon nanotube fluid samples passed therethrough to separate pure carbon nanotubes from carbon nanotubes containing metal impurities; and a fourth step of capturing the pure carbon nanotubes that have been separated from the carbon nanotubes containing metal impurities through the microfluidic channels of the third step at discharge parts in which branch roads are formed at ends of the microfluidic channels.

[0006] US 10 253 309 B2 discloses an apparatus for separating fine particles using magnetophoresis, and a method for separating fine particles using same, and particularly, an apparatus for separating fine particles using magnetophoresis, which includes a fine, patterned magnetic structure capable of quickly and efficiently separating even particles that are weakly magnetized and coupled to fine particles, and a method for separating fine particles using same.

[0007] WO2009006409 A2 discloses the ability to levitate, to separate, and to detect changes in density using diamagnetic particles suspended in solutions containing paramagnetic cations using an inhomogeneous magnetic field. The major advantages of this separation device are that: i) it is a simple apparatus that does not require electric power (a set of permanent magnets and gravity are sufficient for the diamagnetic separation and collection system to work); ii) it is compatible with simple optical detection (provided that transparent materials are used to fabricate the containers / channels where separation occurs; iii) it is simple to collect the separated particles for further processing; iv) it does not require magnetic labeling of the particles / materials; and v) it is small, portable. The method and kits provided provide for separation and collection of materials of different densities, diagnostics for detection of analytes of interest, monitoring of solid-supported chemical reactions and determination of densities of solid and liquid mixtures.

[0008] WO 2017 / 059 353 A1 discloses systems and methods for levitating populations of moieties, cells, or other such units using one or more magnets in a microfluidic environment. These systems and methods may be used to, for example, separate or sort heterogeneous populations of the units from one another, to assembly a multi-unit assembly during the levitating of the units, and to evaluate samples at the point of care in real-time. These systems and methods may also utilize a frame that enables an imaging device, such as a smartphone, to capture the units in real time as they are manipulated in the system.

[0009] Shencheng Ge et al. describe in Magnetic Levitation in Chemistry, Materials Science, and Biochemistry, Angew. Chem. Int. Ed. 2020, 59, 17810-17855 that all matter has density. Today, measurements of density are used to separate and characterize a range of materials (including cells and organisms), and their chemical and / or physical changes in time and space. They describe a density-based technique - magnetic levitation (called "MagLev" for simplicity) - developed and used to solve problems in the fields of chemistry, materials science, and biochemistry. MagLev has two principal characteristics - simplicity, and applicability to a wide range of materials - that make it useful for a number of applications (for example, characterization of materials, quality control of manufactured plastic parts, self-assembly of objects in 3D, separation of different types of biological cells, and bioanalyses).

[0010] Its simplicity and breadth of applications also enable its use in low resource settings (for example - in economically developing regions - in evaluating water / food quality, and in diagnosing disease).Problem to be solved

[0011] It is therefore desirable to provide an extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid and a method for extraction of paramagnetic or diamagnetic particles of different types from a fluid, which at least partially address the above-mentioned technical challenges and at least substantially avoid the disadvantages of known methods and devices.

[0012] It may be desirable to provide an extraction system and a method that are efficient, cost-effective and automatable. Further, it may be desirable to enhance the yield, reduce the costs and time as well as intensify and reduce the footprint of the processes associated with downstream processing.Summary

[0013] This problem is addressed by an extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid and a method for extraction of paramagnetic or diamagnetic particles of different types from a fluid with the features of the independent claims. Advantageous embodiments which might be realized in an isolated fashion or in any arbitrary combinations are listed in the dependent claims as well as throughout the specification.

[0014] In a first aspect, an extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid is disclosed. For this aspect, reference may be made to any definition, embodiment and / or further aspect as disclosed elsewhere herein.

[0015] The term "extraction system" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary system configured for extracting particles from a fluid. In order to be able to extract the particles, the system may further be configured for separating the particles within the fluid. Said separation may be particle type specific, particularly in a manner that a specific type of particles may be accumulated at a specific position within the fluid. Particles of a differing type may be forced at positions differing from the specific position. The accumulated particles of the specific type may be extracted. Consequently, the extraction may be type specific. Particularly a specific type of particles may be extracted from the fluid while a different type of particle remains in the fluid or are extracted from the fluid at a differing specific position.

[0016] The term "extraction" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the process of separating at least one specific particle from a fluid. Extraction may comprise utilizing physical forces, such as a further magnetophoretic force, to achieve the isolation of the specific particles from the rest of the fluid. The goal of the extraction process is to selectively remove the specific particles from the fluid while leaving the rest of the fluid and any unwanted further particles behind.

[0017] The term "type of particle" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a particular particle showing specific physical characteristic making it possible to distinguish particular particles of a specific type from further particles of a differing type. A specific physical characteristic may be a physical characteristic that influences a direction and / or a strength a magnetophoretic force acts on the particular particle. Such a physical characteristic may be at least one of: a magnetic property, preferably the magnetic susceptibility of the particular particle, a volume of the particle, a shape of the particle, one or more dimensions of the particle, the surface characteristics of the particles, the chemical or mechanical interaction of the surface of the particle with the fluid, the surface energy of the particle, the tendency to agglomerate with other particles and others. The magnetic property may depend on the fluid that carries the particular particle. A further specific physical characteristics may be a physical characteristics that influences a direction and / or a strength a drag force acts on the particular particle. Said physical characteristics may be at least one of: a volume of the particle, a roughness of the particle, the surface characteristics of the particle, the chemical or mechanical interaction of the surface of the particle with the fluid, the surface energy of the particle, the tendency to agglomerate with other particles.

[0018] The person skilled in the art may notice that further forces may act on a specific particle, such as gravity, also referred to as the force of gravity, which may act on the particular particle, and the buoyant force, which may act on the particular particle when being in the fluid. Although said forces initially play a minor role, they may still be utilized to separate particles from one another. Consequently, further specific physical characteristics may be related to the force of gravity and / or the buoyancy force.

[0019] The extraction system comprises: at least one magnetic field generator configured for generating a magnetic field having a magnetic field gradient along the z-axis; at least one flow channel configured for guiding the fluid comprising the particles into the magnetic field essentially along the z-axis, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on at least one particle; wherein the extraction system comprises at least one extraction unit configured for extracting the particles of different types from the fluid comprises at least one extractor coil configured for generating at least one further magnetic field having a further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis.

[0020] The term "magnetic field generator" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to device or assembly configured to generate a magnetic field in a specified region of space. The magnetic field generator may be configured for generating a non-uniform magnetic field, wherein the strength and / or direction of the non-uniform magnetic field varies across the specified region of space. In that manner the magnetic field generator may be configured for generating a magnetic field gradient.

[0021] Of particular interest for the present invention may be a magnetic field gradient that is generated along the z-axis. Typically, the magnetic field generator may be configured for generating a magnetic field gradient along a z-axis.

[0022] At least one magnetic field generator may be rotationally symmetrical with respect to the z-axis. At least one magnetic field generated by the magnetic field generator may be rotationally symmetrical with respect to the z-axis.

[0023] The magnetic field generated by the magnetic field generator may be at least partially electrically induced, particularly in a manner that the magnetic field gradient along the z-axis can be adjusted electrically. The term "electrically induced" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a process that is initiated or caused by the application of an electric current and / or an electric voltage. In the context of magnetic fields, for example, an electrically induced magnetic field may be a magnetic field that is generated by passing an electric current through the magnetic field generator.

[0024] The term "adjusting" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the process of setting at least one parameter to generate a particular state or a particular outcome. In case of the present disclosure, the magnetic field gradient and / or the flow rate may be adjusted. Consequently, the magnetic field gradient and / or the flow rate may be set, particularly to a predetermined or known control parameter. The predetermined or known control parameter may be derived in a factory calibration procedure, a calibration procedure and / or in an experiment / sample-related procedure.

[0025] The magnetic field generator comprises at least one of: a superconducting coil; a normal conducting coil; a permanent magnet. The term "normal conducting coil" may refer to a coil made from materials that exhibit standard electrical conductivity, as opposed to superconducting materials.

[0026] The term "flow channel" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a pathway or conduit through which a fluid may be directed to flow, thereby guiding the movement of the fluid in a controlled manner.

[0027] The flow channel may be configured to guide the fluid into and / or through the magnetic field. Consequently, the flow channel may be configured to pass into or through the magnetic field. The at least one magnetic field generator, or elements of the magnetic field generator, may be arranged, at least in part, around the flow channel, preferably symmetrically around the flow channel.

[0028] The flow channel may be configured to guide the fluid into the magnetic field such that a main flow direction of the guided fluid is essentially parallel and / or essentially coaxial to the magnetic field gradient along a z-axis. The flow channel may comprise a central axis that is essentially parallel and / or essentially coaxial to the magnetic field gradient along a z-axis.

[0029] The term "essentially" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a maximum deviation from a specific value, preferably of 20°, 15°, 10°, 5°, 3°, 2° or 1°. "Essentially along the z-axis" may refer to being parallel and / or coaxial to the z-axis with a maximum deviation thereof of 20°, 15°, 10°, 5°, 3°, 2° or 1°.

[0030] For example , the at least one magnetic field generator may comprise at least one opening, wherein the at least one flow channel may be configured for guiding the fluid comprising the particles into the magnetic field through the opening of the at least one magnetic field generator.

[0031] In a separation phase, o a flow rate of the fluid being guided into the magnetic field may be adjusted; and / or o the magnetic field gradient along the z-axis of the at least one magnetic field generator may be adjusted; preferably by using a control unit, in a manner that at least the magnetophoretic force acting on particles and at least the drag force exerted by the flowing fluid acting on particles balance each other in a manner that particles of a specific type are held at a specific position along the z-axis.

[0032] As already indicated, the extraction system comprises the at least one extraction unit configured for extracting the particles of different types from the fluid, wherein the at least one extraction unit comprises the at least one extractor coil configured for generating the at least one further magnetic field having the further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis.

[0033] Thereby, a further magnetophoretic force induced by the further magnetic field gradient generated by the at least one extractor coil may act on the particles of the specific type held at the specific position along the z-axis in a manner that the at least one particle drifts out of the fluid, in an extraction phase. Particles of any further specific type that is different from the specific type may not be held at the specific position and may, therefore, not be extracted from the fluid. During the extraction phase, the flow rate of the fluid being guided into the magnetic field may remain constant; and the magnetic field gradient along the z-axis of the at least one magnetic field generator may remain constant.

[0034] The term "extraction unit" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a device comprising at least one extractor coil configured for generating the further magnetic field gradient in a tunable manner. The at least one extractor coil may be configured to generate no further magnetic field gradient when the particles of the specific type are not held at the specific position along the z-axis. The at least one extractor coil may be configured to generate the further magnetic field gradient when the particles of the specific type are held at the specific position along the z-axis. Consequently, the at least one extractor coil may be configured to ramp up the further magnetic field gradient when the particles of the specific type are held at the specific position along the z-axis.

[0035] As already indicated, the further magnetic field gradient has a component that is orthogonal to the z-axis. The magnetic field gradient has a direction. Said direction may have a plurality of components, wherein each component is a projection of the direction of the magnetic field gradient on differing axes of a coordinate system. The term "component that is orthogonal to the z-axis" may refer to a specific projection on an axis that is orthogonal to the z-axis.

[0036] For the further magnetic field gradient to have a component that is orthogonal to the z-axis, at least one of: The direction of the further magnetic field gradient may be orthogonal to the z-axis. In this case, the component of the further magnetic field gradient that is orthogonal to the z-axis may be the only component of the further magnetic field gradient. The further magnetic field gradient may have the component that is orthogonal to the z-axis and the further magnetic field gradient may have a component that is parallel to the z-axis. Typically, the component that is orthogonal to the z-axis may be larger than the component that is parallel to the z-axis gradient, such as 2, 5, 10 or 20 times larger.

[0037] In other words, the further magnetic field gradient may be essentially orthogonal to the z-axis. The further magnetic field gradient may be orthogonal to the z-axis a maximum deviation of 20°, 15°, 10°, 5°, 3°, 2° or 1°.

[0038] The disclosure, thereby, may address the need for more efficient, cost-effective and automated systems and methods for isolating and purifying desired products, such as particles, from complex mixtures. In the biopharmaceutical sector, the disclosure may seek to enhance the yield and reduce the costs associated with downstream processing, which is currently dominated by expensive and high-maintenance methods like chromatography.

[0039] The at least one extraction unit may further comprise at least one extraction channel. The at least one extraction channel may be configured for extracting particles from the flow channel. The at least one particle drifting out of the fluid may consequently drift through the at least one extraction channel out of the fluid. The at least one extraction channel may guide the at least one particle in a reservoir.

[0040] The at least one extraction unit may be or may comprise a plurality of extraction units, wherein each extraction unit of the plurality of extraction units is located at a different z-position on the z-axis. By using a plurality of extraction units at different z-position on the z-axis, a plurality of differing types of particles may be extracted from the fluid, specifically simultaneously.

[0041] Typically, the flow rate of the fluid being guided into and / or through the magnetic field may be independent of the z-position. Consequently, the flow rate may be constant at different z-positions. On the other hand, the flow rate may depend on the z-position, particularly in case a cross section of the at least one flow channel changes along the z-axes. The magnetic field gradient, specifically the strength of the magnetic field gradient may be different at different z-positions. As a result, for different types of particles, at least the drag force and at least the magnetophoretic force may balance at different specific z-positions depending on the types of the particles. Consequently, the plurality of different types of particles may be extracted from the fluid by the plurality of extraction units as the different types of particles are extracted at the different specific z-positions.

[0042] Alternatively or in addition, the at least one magnetic field generator may comprise two or more magnetic field generators, wherein each magnetic field generator of the two or more magnetic field generators generates a magnetic field having a different magnetic field strength, wherein the two or more magnetic field generators are spatially separated and each magnetic field generator of the two or more magnetic field generators is arranged at a different z-position on the z-axis. The at least one extraction unit may be arranged between two neighboring magnetic field generators of the two or more magnetic field generators in respect to the z-axis.

[0043] The at least one magnetic field generator may have a triangular outer shape. The triangular outer shape may allow generating a non-uniform magnetic field with varying strengths. Thereby, the magnetic field gradient may be generated in an easy and efficient manner.

[0044] The z-axis may be parallel to a direction of gravity, also referred to as force of gravity, with a maximum deviation thereof of 20°, 10°, 5°, 3° or 1°. When the z-axis is parallel to the direction of the force of gravity, the force of gravity and the buoyancy forces may act on the particles in the fluid along the z-axis. Consequently, when adjusting the flow rate of the fluid being guided into the magnetic field and / or adjusting the magnetic field gradient in a manner that particles of a specific type are held at a specific position along the z-axis, also the force of gravity and / or the buoyancy force may be balanced.

[0045] Typically, a drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field, or a magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles may be larger than the force of gravity, preferably at least 2 times larger, preferably 10 times larger. Therefore, the influence of the force of gravity may be small when compared to the drag force or the magnetophoretic force.

[0046] For the magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles to be larger than the force of gravity, the at least one magnetic field generator may be further configured for generating the magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles that is larger than the force of gravity.

[0047] The system may further comprise: at least one flow generating unit configured for generating a flow of the fluid through the flow channel in order to guide the fluid comprising the particles into the magnetic field.

[0048] The term "flow generating unit" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a device or an assembly configured to initiate and / or maintain the movement or flow of a fluid through a system or conduit. The flow generating unit may be or may comprise at least one kind of pump, such as a centrifugal, rotary, peristaltic or gravity pump, etc..

[0049] For the drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field to be larger than the force of gravity, the at least one flow inducing unit may be further configured for generating the drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field that is larger than the force of gravity.

[0050] The system may further comprise: at least one control unit configured for at least one of: o triggering the adjustment of a flow rate of the fluid being guided into the magnetic field, preferably by transmitting at least one control signal to the at least one flow generating unit; o triggering the adjustment of the magnetic field gradient along the z-axis of the at least one magnetic field generator, preferably by transmitting at least one further control signal to the at least one magnetic field generator; in a manner that at least the magnetophoretic force acting on particles and at least the drag force exerted by the flowing fluid acting on particles balance each other in a manner that particles of a specific type are held at a specific position along the z-axis.

[0051] The term "control unit" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a component configured to manage the operation of other devices or systems by processing input signals and generating appropriate output commands. The control unit may function as an open loop system. The control unit may be configured to use at least one predefined or known control parameter in order to adjust the flow rate and / or the magnetic field gradient. The control unit may be configured to select a specific at least one predefined control parameter depending on the fluid and / or the specific type of particle to be extracted and adjust the flow rate and / or the magnetic field gradient, accordingly. The predefined control parameter may be derived in a factory calibration procedure or calibrated based on the specific experiment or requirement.

[0052] As already indicated, the flow rate and / or the magnetic field gradient may be adjusted in a manner that particles of a specific type are held at a specific position along the z-axis. Therefore, the forces that are acting on the particles of a specific type may have to be balanced in a manner that the forces acting on the particles of a specific type negate each other, resulting in no net force acting on the particles of a specific type.

[0053] Typically, the following forces may act on the particles in the fluid: The magnetophoretic force F m = 2 πR 3 μ 0 μ r K ∇ H 2 , where F m represents the magnetophoretic force, H represents the magnetic field, R represents the radius of the particle, µ r represents the relative permeability of the fluid, µ r,p represents the relative permeability of the particle, and K is defined as K = μ r , p − μ r μ r , p + 2 μ r The direction of the magnetophoretic force depends on the magnetic properties of the particles. The drag force F d = 1 2 ρ v 2 CA , where F d represents the drag force, ρ represents the density of the fluid, v represents the flow velocity relative to the particle, C represents the drag coefficient and A represents the cross-sectional area of the particle. The force of gravity F g = Mg , where F g represents the gravity force, M represents the mass of the particle and g represents the acceleration due to gravity. The buoyancy force F b = V Δ pg , where F b represents the buoyancy force, V represents the volume of the particle, Δρ represents the mass density difference between the particle and the background fluid g represents the gravitational acceleration.

[0054] As already indicated, the flow rate and / or the magnetic field gradient may be adjusted. By doing so, the magnetophoretic force induced by the magnetic field gradient and the drag force may be adjusted in a manner that they negate each other. Consequently, a direction of the magnetophoretic force and a direction of the drag force may be opposite to each other. Further, an absolute value of the strength of the magnetophoretic force and an absolute value of the strength of the drag force may be equal to each other, particularly in case a strength of the force of gravity and / or a strength of the buoyancy force each are small compared to the strength of the magnetophoretic force and / or the strength of the drag force.

[0055] As already indicated, the z-axis may be parallel to the direction of the force of gravity. In this case, the z-axis may be further parallel to the buoyancy force. The force of gravity and the buoyancy force may then also be parallel to the magnetophoretic force and the drag force. When the flow rate and / or the magnetic field gradient are adjusted, the force of gravity and the buoyancy force may, in addition to the magnetophoretic force and the drag force, be balanced in a manner that all forces negate each other and the particles of the specific type are held at a specific position along the z-axis.

[0056] In summary, the flow rate and / or the magnetic field gradient may be adjusted in a manner that the magnetophoretic force and the drag force; the magnetophoretic force, the drag force and the force of gravity; the magnetophoretic force, the drag force and the buoyancy force; or the magnetophoretic force, the drag force, the force of gravity and the buoyancy force balance each other in a manner that the respective forces negate each other, resulting in no net force acting on the particle. Further forces acting on the particles may additionally be considered and negated. Since the forces may depend on physical characteristics of the particles, the forces, typically, balance for a specific type of particle. As a result, particles of a specific type are held at a specific position along the z-axis.

[0057] The fluid may be a liquid, preferably an aqueous solution comprising or containing one or more of: Manganese(II) chloride, MnCl2, Mangan(III)bromid, MnBr3, Copper(II) sulfate, CuSO4, Gadolinium(III) chloride, GdCl3, Dysprosium(III) chloride, DyCl3, Holmium(III) chloride, HoCl3, diethylenetriamine pentacetic acid, Gd-DTPA, a Gadolinium, GD, chelated compound, individually or in combination.

[0058] In a further aspect, a method for extraction of paramagnetic or diamagnetic particles of different types from a fluid is disclosed. For this aspect, reference may be made to any definition, Embodiment and / or further aspect as disclosed elsewhere herein.

[0059] The steps of the method may be performed in the given order. A different order, however, may also be feasible. Further, two or more of the method steps may be performed simultaneously. Thereby, the method steps may at least partly overlap in time. Further, the method steps may be performed once or repeatedly. Thus, one or more or even all of the method steps may be performed once or repeatedly. The method may comprise additional method steps, which are not listed herein.

[0060] The method comprising: flowing the fluid comprising the particles into a magnetic field having a magnetic field gradient along a z-axis by utilizing at least one flow channel, wherein the magnetic field gradient is generated by at least one magnetic field generator; in a separation phase, adjusting a flow rate of the fluid so that at least a magnetophoretic force acting on the particles and at least a drag force exerted by the flowing fluid acting on the particles balance each other in a manner that particles of a specific type are held at a specific z-position of the z-axis; in an extraction phase, applying an electric current to at least one extractor coil and, thereby, generating at least one further magnetic field having a further magnetic field gradient, preferably when the particles of the specific type are held at the specific z-position of the z-axis, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis, wherein the at least one extractor coil is comprised by at least one extraction unit.

[0061] The method step flowing the fluid into a magnetic field may be performed before the method step adjusting a flow rate of the fluid.

[0062] Consequently, the fluid may be flowing into the magnetic field at an arbitrary flow rate and then the flow rate may be adjusted.

[0063] The method steps flowing the fluid into a magnetic field and adjusting a flow rate of the fluid may be performed simultaneously. Alternatively, the method step adjusting a flow rate of the fluid may be performed before the method step flowing the fluid into a magnetic field.

[0064] Consequently, the fluid may be flowing into the magnetic field already with the adjusted flow rate.

[0065] During the separation phase the flow rate of the fluid may be adjusted. The adjusted flow rate may remain constant during the extraction phase.

[0066] The term "separation phase" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a specific stage in a process in which the particles in the fluid are spatially separated in a type specific manner based on the physical characteristics of the particles.

[0067] The term "extraction phase" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a stage in a process in which the particles are removed or isolated from the fluid.

[0068] The method may be performed by using an extraction system as elsewhere disclosed herein.

[0069] The method may further comprise: adjusting, in the separation phase, the magnetic field gradient along the z-axis of the at least one magnetic field generator for further balancing at least the magnetophoretic force acting on the particles and at least the drag force exerted by the flowing fluid acting on the particles in a manner that the particles of the specific type are held at the specific z-position on the z-axis.

[0070] For adjusting the magnetic field gradient along the z-axis of the at least one magnetic field generator, an electric current through at least one coil comprised by the at least one magnetic field generator may be adjusted.

[0071] The electric current through the at least one coil of the at least one magnetic field generator may be reduced during the extraction phase. The time required for the separation of the particles decreases when the flow rate increases. Since an increased flow rate is associated with stronger forces that can overcome the natural attractions holding the particles together, like Van der Waals forces or surface energy. However, when the flow rate increases, it also induces an increased drag force on the particles. Depending on the geometry and displacement of the parts of the system and the generated gradients, this increased drag force could push the particles closer together, reducing the margin of operability of the extraction system. In fact, as a result, the extraction channels used to extract the particles would need to be closer to each other, which may make the separation process less precise and harder to manage. By reducing the flow rate in a later stage, the particles could spread out more. This gives them more space between each other, making it easier to extract them effectively.

[0072] Particles of different types may be extracted in a step wise manner by adapting the drag force and / or the magnetophoretic force acting on the particles such that particles of different types are moved step wise to a z-position on the z-axis of the extraction unit, preferably at least one extraction channel of the extraction unit. The stepwise approach may help to ensure that each type of particle is isolated more effectively, reducing cross-contamination and improving the purity of the extracted particles.

[0073] As used in the following, the terms "have", "comprise" or "include" or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions "A has B", "A comprises B" and "A includes B" may both refer to a situation in which, besides B, no other element is present in A (i.e. a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements.

[0074] Further, it shall be noted that the terms "at least one", "one or more" or similar expressions indicating that a feature or element may be present once or more than once typically will be used only once when introducing the respective feature or element. In the following, in most cases, when referring to the respective feature or element, the expressions "at least one" or "one or more" will not be repeated, non-withstanding the fact that the respective feature or element may be present once or more than once.

[0075] Further, as used in the following, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features, without restricting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The invention may, as the skilled person will recognize, be performed by using alternative features. Similarly, features introduced by "in an embodiment of the invention" or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments of the invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention.

[0076] Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged: Embodiment 1: An extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid, the system comprising: at least one magnetic field generator configured for generating a magnetic field having a magnetic field gradient along a z-axis; at least one flow channel configured for guiding the fluid comprising the particles into the magnetic field essentially along the z-axis, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on the at least one particle; wherein the extraction system comprises at least one extraction unit configured for extracting the particles of different types from the fluid, wherein the at least one extraction unit comprises at least one extractor coil configured for generating at least one further magnetic field having a further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis. Embodiment 2: The extraction system according to the preceding Embodiment, wherein the at least one magnetic field generator comprises at least one opening, preferably wherein the opening is a central opening, wherein the at least one flow channel is configured for guiding the fluid comprising the particles into the magnetic field through the opening of the at least one magnetic field generator. Embodiment 3: The extraction system according to any one of the preceding Embodiments, wherein the at least one extraction unit further comprises at least one extraction channel, wherein the at least one extraction channel is configured for extracting particles from the flow channel. Embodiment 4: The extraction system according to the preceding Embodiments, wherein a further magnetophoretic force induced by the further magnetic field gradient generated by the at least one extractor coil acts on the at least one particle in a manner that the at least one particle drifts into the at least one extraction channel. Embodiment 5: The extraction system according to any one of the preceding Embodiments, wherein the at least one extraction unit is or comprises a plurality of extraction units, wherein each extraction unit of the plurality of extraction units is located at a different z-position on the z-axis. Embodiment 6: The extraction system according to any one of the preceding Embodiments, wherein the magnetic field generated by the magnetic field generator is at least partially electrically induced, particularly in a manner that the magnetic field gradient along the z-axis can be adjusted electrically. Embodiment 7: The extraction system according to any one of the preceding Embodiments, wherein the magnetic field generator comprises at least one of: a superconducting coil; a normal conducting coil; a permanent magnet. Embodiment 8: The extraction system according to any one of the preceding Embodiments, wherein the at least one magnetic field generator is rotationally symmetrical with respect to the z-axis. Embodiment 9: The extraction system according to any one of the preceding Embodiments, wherein the at least one magnetic field generator comprises two or more magnetic field generators, wherein each magnetic field generator of the two or more magnetic field generators generates a magnetic field having a different magnetic field strength, wherein the two or more magnetic field generators are spatially separated, wherein each magnetic field generator of the two or more magnetic field generators is arranged at a different z-position on the z-axis. Embodiment 10: The extraction system according to the preceding Embodiment, wherein the at least one extraction unit is arranged between two neighboring magnetic field generators of the two or more magnetic field generators in respect to the z-axis. Embodiment 11: The extraction system according to any one of the preceding Embodiments 1-8, wherein the at least one magnetic field generator has a triangular outer shape. Embodiment 12: The extraction system according to any one of the preceding Embodiments, wherein the z-axis is parallel to a direction of gravity with a maximum deviation thereof of 20°, 10°, 5°, 3° or 1°. Embodiment 13: The extraction system according to any one of the preceding Embodiments, wherein one of: a drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field, a magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles is larger than the force of gravity, preferably at least 2 times larger, preferably 10 times larger. Embodiment 14: The extraction system according to the preceding Embodiment, wherein, for the magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles to be larger than the force of gravity, the at least one magnetic field generator is further configured for generating the magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles that is larger than the force of gravity. Embodiment 15: The extraction system according to any one of the preceding Embodiments, the system further comprising: at least one flow generating unit configured for generating a flow of the fluid through the flow channel in order to guide the fluid comprising the particles into the magnetic field. Embodiment 16: The extraction system according to the preceding Embodiment, wherein, for the drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field to be larger than the force of gravity, the at least one flow inducing unit is further configured for generating the drag force acting on the particles that is exerted by the flowing fluid being guided into the magnetic field that is larger than the force of gravity. Embodiment 17: The extraction system according to any one of the preceding Embodiments, the system further comprising: at least one control unit configured for at least one of: o triggering the adjustment of a flow rate of the fluid being guided into the magnetic field, preferably by transmitting at least one control signal to the at least one flow generating unit; o triggering the adjustment of the magnetic field gradient along the z-axis of the at least one magnetic field generator, preferably by transmitting at least one further control signal to the at least one magnetic field generator; in a manner that at least the magnetophoretic force acting on particles and at least the drag force exerted by the flowing fluid acting on particles balance each other in a manner that particles of a specific type are held at a specific position along the z-axis. Embodiment 18: The extraction system according to any one of the preceding Embodiments, wherein the fluid is a liquid, preferably an aqueous solution comprising or containing one or more of: Manganese(II) chloride, MnCl2, Mangan(III)bromid, MnBr3, Copper(II) sulfate, CuSO4, Gadolinium(III) chloride, GdCl3, Dysprosium(III) chloride, DyCl3, Holmium(III) chloride, HoCl3, diethylenetriamine pentacetic acid, Gd-DTPA, a Gadolinium, GD, chelated compound, individually or in combination. Embodiment 19: Method for extraction of paramagnetic or diamagnetic particles of different types from a fluid, the method comprising: flowing the fluid comprising the particles into a magnetic field having a magnetic field gradient along a z-axis by utilizing at least one flow channel, wherein the magnetic field gradient is generated by at least one magnetic field generator; in a separation phase, adjusting a flow rate of the fluid so that at least a magnetophoretic force acting on the particles and at least a drag force exerted by the flowing fluid acting on the particles balance each other in a manner that particles of a specific type are held at a specific z-position of the z-axis; in an extraction phase, applying an electric current to at least one extractor coil and, thereby, generating at least one further magnetic field having a further magnetic field gradient, preferably when the particles of the specific type are held at the specific z-position of the z-axis, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis, wherein the at least one extractor coil is comprised by at least one extraction unit. Embodiment 20: Method according to the preceding Embodiment, wherein the method is performed by using an extraction system according to any one of the preceding Embodiments referring to an extraction system. Embodiment 21: Method according to any one of the preceding method Embodiments, the method further comprising: adjusting, in the separation phase, the magnetic field gradient along the z-axis of the at least one magnetic field generator for further balancing at least the magnetophoretic force acting on the particles and at least the drag force exerted by the flowing fluid acting on the particles in a manner that the particles of the specific type are held at the specific z-position on the z-axis. Embodiment 22: Method according to the preceding Embodiment, wherein, for adjusting the magnetic field gradient along the z-axis of the at least one magnetic field generator, an electric current through at least one coil comprised by the at least one magnetic field generator is adjusted. Embodiment 23: Method according to the preceding method Embodiment, wherein the electric current through the at least one coil of the at least one magnetic field generator is reduced during the extraction phase. Embodiment 24: Method according to the preceding Embodiment, wherein particles of different types are extracted in a step wise manner by adapting the drag force and / or the magnetophoretic force acting on the particles such that particles of different types are moved step wise to a z-position on the z-axis of the extraction unit, preferably at least one extraction channel of the extraction unit. Short description of the Figures

[0077] Further optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features may be realized in an isolated fashion as well as in any arbitrary feasible combination, as the skilled person will realize. The scope of the invention is not restricted by the preferred embodiments. The embodiments are schematically depicted in the Figures. Therein, identical reference numbers in these Figures refer to identical or functionally comparable elements.

[0078] In the Figures: Figure 1shows an exemplary extraction system for extraction of paramagnetic or diamagnetic particles of different types from a fluid; Figure 2shows a typically magnetic field generated by an exemplary magnetic field generator; Figure 3shows a typically flow rate field generated by a flow of the fluid in an exemplary flow channel; Figure 4shows a further typically magnetic field generated by a further exemplary magnetic field generator; and Figure 5shows an exemplary method for extraction of paramagnetic or diamagnetic particles of different types from a fluid. Detailed description of the embodiments

[0079] Figure 1 shows an exemplary extraction system 110 for extraction of paramagnetic or diamagnetic particles 112 of different types from a fluid 114. The fluid 114 and the particles 112 in the fluid 114 may be in a may be first reservoir 126.

[0080] The system 110 comprises: at least one magnetic field generator 116 configured for generating a magnetic field having a magnetic field gradient along a z-axis 118; at least one flow channel 120 configured for guiding the fluid 114 comprising the particles 112 into the magnetic field essentially along the z-axis 118, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on the at least one particle 112; wherein the extraction system 110 comprises at least one extraction unit 122 configured for extracting the particles 112 of different types from the fluid 114, wherein the at least one extraction unit 122 comprises at least one extractor coil 124 configured for generating at least one further magnetic field having a further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis 118.

[0081] The magnetic field generated by the magnetic field generator 116 may be at least partially electrically induced, particularly in a manner that the magnetic field gradient along the z-axis 118 can be adjusted electrically. The magnetic field generator 116 may comprise at least one of: a superconducting coil; a normal conducting coil; a permanent magnet.

[0082] The flow channel 120 may be comprised by a flow channel system 128. The flow channel system 128 may fluidically connect the first reservoir 126 and a second reservoir 130. The system 110 may further comprise: at least one flow generating unit 132 configured for generating a flow of the fluid 114 through the flow channel 120 in order to guide the fluid 114 comprising the particles 112 into the magnetic field.

[0083] The at least one flow generating unit 132 may be further configured for generating the flow in a manner that the fluid 114 and the particles 112 in the fluid 114 may flow from the first reservoir 126 into the second reservoir 126, particularly through the magnetic field.

[0084] The at least one magnetic field generator 116 may comprises at least one opening 134, preferably wherein the opening 134 is a central opening, wherein the at least one flow channel 120 is configured for guiding the fluid 114 comprising the particles 112 into the magnetic field through the opening 134 of the at least one magnetic field generator116. The at least one magnetic field generator 116 may be rotationally symmetrical with respect to the z-axis 118. The at least one magnetic field generator 116 may have a triangular outer shape.

[0085] The at least one extraction unit 122 further may comprise at least one extraction channel 136, wherein the at least one extraction channel 136 is configured for extracting particles 112 from the flow channel 120. Particularly therefore, a further magnetophoretic force induced by the further magnetic field gradient generated by the at least one extractor coil 124 acts on the at least one particle 112 in a manner that the at least one particle 112 drifts into the at least one extraction channel 136. The at least one particle 112 may drift through the at least one extraction channel 136 into at least one third reservoir 138.

[0086] The at least one extraction unit 122 is or comprises a plurality of extraction units 122, wherein each extraction unit 122 of the plurality of extraction units 122 is located at a different z-position on the z-axis 118. The plurality of extraction units 122 has a plurality of extraction channels 136, which may fed the extracted particles 112 into the same at least one third reservoirs 138 and / or differing at least one third reservoirs 138.

[0087] The system 110 further may comprise: at least one control unit 140 configured for at least one of: o triggering the adjustment of a flow rate of the fluid 114 being guided into the magnetic field, preferably by transmitting at least one control signal to the at least one flow generating unit 132; o triggering the adjustment of the magnetic field gradient along the z-axis 118 of the at least one magnetic field generator 116, preferably by transmitting at least one further control signal to the at least one magnetic field generator 116; in a manner that at least the magnetophoretic force acting on particles 112 and at least the drag force exerted by the flowing fluid 114 acting on particles 112 balance each other in a manner that particles 112 of a specific type are held at a specific position along the z-axis 118.

[0088] The z-axis 118 is parallel to a direction of gravity with a maximum deviation thereof of 20°, 10°, 5°, 3° or 1°. A drag force acting on the particles 112 that is exerted by the flowing fluid 114 being guided into the magnetic field or a magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles 112 may be larger than the force of gravity, preferably at least 2 times larger, preferably 10 times larger.

[0089] Figure 2 shows a typically magnetic field generated by an exemplary magnetic field generator 116. On the horizontal axis 142, a position on an axis orthogonal to the z-axis is indicated in Millimeter. On the vertical axis 144, a position on the z-axis is indicated in Millimeter. The curved lines indicate the magnetic flux of the magnetic field generated by the magnetic field generator 116.

[0090] Figure 3 shows a typically flow rate field generated by a flow of the fluid 114 in an exemplary flow channel 120. On the horizontal axis 146, a position on an axis orthogonal to the z-axis is indicated in Millimeter. On the vertical axis 148, a position on the z-axis is indicated in Millimeter. The arrows indicate the velocity of the flow of the fluid 114.

[0091] Figure 4 shows a further typically magnetic field generated by a further exemplary magnetic field generator 116. On the horizontal axis 150, a position on an axis orthogonal to the z-axis is indicated in Millimeter. On the vertical axis 152, a position on the z-axis is indicated in Millimeter. The curved lines indicate the magnetic flux of the magnetic field generated by the magnetic field generator 116.

[0092] As may be derived from Figure 4, the at least one magnetic field generator 116 may comprises two or more magnetic field generators 116, wherein each magnetic field generator 116 of the two or more magnetic field generators 116 generates a magnetic field having a different magnetic field strength, wherein the two or more magnetic field generators 116 are spatially separated, wherein each magnetic field generator 116 of the two or more magnetic field generators 116 is arranged at a different z-position on the z-axis. The at least one extraction unit 122 may be arranged between two neighboring magnetic field generators 116 of the two or more magnetic field generators 116 in respect to the z-axis.

[0093] Figure 5 shows an exemplary method 154 for extraction of paramagnetic or diamagnetic particles 112 of different types from a fluid 114. The method 154 comprises: (denoted by reference number 156) flowing the fluid 114 comprising the particles 112 into a magnetic field having a magnetic field gradient along a z-axis by utilizing at least one flow channel 120, wherein the magnetic field gradient is generated by at least one magnetic field generator 116; (denoted by reference number 158) in a separation phase, adjusting a flow rate of the fluid 114 so that at least a magnetophoretic force acting on the particles 112 and at least a drag force exerted by the flowing fluid 114 acting on the particles 112 balance each other in a manner that particles 112 of a specific type are held at a specific z-position of the z-axis; (denoted by reference number 160) in an extraction phase, applying an electric current to at least one extractor coil 124 and, thereby, generating at least one further magnetic field having a further magnetic field gradient, preferably when the particles 112 of the specific type are held at the specific z-position of the z-axis, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis, wherein the at least one extractor coil 124 is comprised by at least one extraction unit 122.

[0094] The method further may comprise: (denoted by reference number 162) adjusting, in the separation phase, the magnetic field gradient along the z-axis of the at least one magnetic field generator 116 for further balancing at least the magnetophoretic force acting on the particles 112 and at least the drag force exerted by the flowing fluid 114 acting on the particles 112 in a manner that the particles 112 of the specific type are held at the specific z-position on the z-axis.

[0095] For adjusting the magnetic field gradient along the z-axis of the at least one magnetic field generator 116 (denoted by reference number 162), an electric current through at least one coil comprised by the at least one magnetic field generator 116 is adjusted.

[0096] The electric current through the at least one coil of the at least one magnetic field generator 116 is reduced during the extraction phase.

[0097] Particles 112 of different types may be extracted in a step wise manner by adapting the drag force and / or the magnetophoretic force acting on the particles 112 such that particles 112 of different types are moved step wise to a z-position on the z-axis of the extraction unit 122, preferably to at least one extraction channel of the extraction unit 122.List of reference numbers

[0098] 110extraction system 112paramagnetic or diamagnetic particle 114fluid 116magnetic field generator 118z-axis 120flow channel 122extraction unit 124extractor coil 126first reservoir 128flow channel system 130second reservoir 132flow generating unit 134opening 136extraction channel 138third reservoir 140control unit 142horizontal axis 144vertical axis 146horizontal axis 148vertical axis 150horizontal axis 152vertical axis 154method for extraction of paramagnetic or diamagnetic particles of different types from a fluid 156flowing the fluid comprising the particles into a magnetic field 158adjusting a flow rate of the fluid 160applying an electric current to at least one extractor coil 162adjusting the magnetic field gradient along the z-axis

Examples

Embodiment Construction

[0079]Figure 1 shows an exemplary extraction system 110 for extraction of paramagnetic or diamagnetic particles 112 of different types from a fluid 114. The fluid 114 and the particles 112 in the fluid 114 may be in a may be first reservoir 126.

[0080]The system 110 comprises:

at least one magnetic field generator 116 configured for generating a magnetic field having a magnetic field gradient along a z-axis 118; at least one flow channel 120 configured for guiding the fluid 114 comprising the particles 112 into the magnetic field essentially along the z-axis 118, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on the at least one particle 112;

wherein the extraction system 110 comprises at least one extraction unit 122 configured for extracting the particles 112 of different types from the fluid 114, wherein the at least one extraction unit 122 comprises at least one extractor coil 124 configured for generating at least one further ma...

Claims

1. An extraction system (110) for extraction of paramagnetic or diamagnetic particles (112) of different types from a fluid (114), the system (110) comprising: - at least one magnetic field generator (116) configured for generating a magnetic field having a magnetic field gradient along a z-axis; - at least one flow channel (120) configured for guiding the fluid (114) comprising the particles (112) into the magnetic field essentially along the z-axis, preferably in a manner that a magnetophoretic force induced by the magnetic field gradient acts on the at least one particle; characterized in that the extraction system (110) comprises at least one extraction unit (122) configured for extracting the particles (112) of different types from the fluid (114), wherein the at least one extraction unit (122) comprises at least one extractor coil (124) configured for generating at least one further magnetic field having a further magnetic field gradient, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis.

2. The extraction system (110) according to the preceding claim, wherein the at least one extraction unit (122) is or comprises a plurality of extraction units (122), wherein each extraction unit (122) of the plurality of extraction units (122) is located at a different z-position on the z-axis.

3. The extraction system (110) according to any one of the preceding claims, wherein the magnetic field generated by the magnetic field generator (116) is at least partially electrically induced, particularly in a manner that the magnetic field gradient along the z-axis can be adjusted electrically.

4. The extraction system (110) according to any one of the preceding claims, wherein the magnetic field generator (116) comprises at least one of: a superconducting coil; a normal conducting coil; a permanent magnet.

5. The extraction system (110) according to any one of the preceding claims, wherein the at least one magnetic field generator (116) is rotationally symmetrical with respect to the z-axis.

6. The extraction system (110) according to any one of the preceding claims, wherein the at least one magnetic field generator (116) comprises two or more magnetic field generators (116), wherein each magnetic field generator (116) of the two or more magnetic field generators (116) generates a magnetic field having a different magnetic field strength, wherein the two or more magnetic field generators (116) are spatially separated, wherein each magnetic field generator (116) of the two or more magnetic field generators (116) is arranged at a different z-position on the z-axis.

7. The extraction system (110) according to the preceding claim, wherein the at least one extraction unit (122) is arranged between two neighboring magnetic field generators (116) of the two or more magnetic field generators (116) in respect to the z-axis.

8. The extraction system (110) according to any one of the preceding claims 1-6, wherein the at least one magnetic field generator (116) has a triangular outer shape.

9. The extraction system (110) according to any one of the preceding claims, wherein the z-axis is parallel to a direction of gravity with a maximum deviation thereof of 20°, 10°, 5°, 3° or 1°.

10. The extraction system (110) according to any one of the preceding claims, wherein one of: - a drag force acting on the particles (112) that is exerted by the flowing fluid (114) being guided into the magnetic field, - a magnetophoretic force resulting from the magnetic field gradient that is acting on the magnetic properties of the particles (112) is larger than the force of gravity, preferably at least 2 times larger, preferably 10 times larger.

11. The extraction system (110) according to any one of the preceding claims, wherein the fluid (114) is a liquid, preferably an aqueous solution comprising or containing one or more of: - Manganese(II) chloride, MnCl2, - Mangan(III)bromid, MnBr3, - Copper(II) sulfate, CuSO4, - Gadolinium(III) chloride, GdCl3, - Dysprosium(III) chloride, DyCl3, - Holmium(III) chloride, HoCl3, - diethylenetriamine pentacetic acid, Gd-DTPA, - a Gadolinium, GD, chelated compound, individually or in combination.

12. Method for extraction of paramagnetic or diamagnetic particles (112) of different types from a fluid (114), the method comprising: - flowing the fluid (114) comprising the particles (112) into a magnetic field having a magnetic field gradient along a z-axis by utilizing at least one flow channel (120), wherein the magnetic field gradient is generated by at least one magnetic field generator (116); - in a separation phase, adjusting a flow rate of the fluid (114) so that at least a magnetophoretic force acting on the particles (112) and at least a drag force exerted by the flowing fluid (114) acting on the particles (112) balance each other in a manner that particles (112) of a specific type are held at a specific z-position of the z-axis; - in an extraction phase, applying an electric current to at least one separator coil and, thereby, generating at least one further magnetic field having a further magnetic field gradient, preferably when the particles (112) of the specific type are held at the specific z-position of the z-axis, wherein the further magnetic field gradient has a component that is orthogonal to the z-axis, wherein the at least one extractor coil (124) is comprised by at least one extraction unit (122).

13. Method according to the preceding method claim, the method further comprising: - adjusting, in the separation phase, the magnetic field gradient along the z-axis of the at least one magnetic field generator (116) for further balancing at least the magnetophoretic force acting on the particles (112) and at least the drag force exerted by the flowing fluid (114) acting on the particles (112) in a manner that the particles (112) of the specific type are held at the specific z-position on the z-axis.

14. Method according to any one of the preceding method claims, wherein particles (112) of different types are extracted in a step wise manner by adapting at least one of: the drag force; the magnetophoretic force acting on the particles (112) such that particles (112) of different types are moved step wise to a z-position on the z-axis of the extraction unit (122), preferably at least one extraction channel of the extraction unit (122).

Images