A method and a system for sorting particles

Abstract

The present disclosure generally relates to particle manipulation and separation technologies, and more particularly relates to a method and a system for sorting particles Further, the method may include receiving, by a particle sorting system (100), a quantity of fluid includes particles with motility. Further, the method may include generating, by a rotating magnetic field using coils. Furthermore, the method may include disposing a cuvette. The cuvette may include suspension of the particles in deionized water vertically within the region of the decreasing rotating magnetic field strength, with a highest field strength at the bottom of the cuvette. Further, the method may include applying the rotating magnetic field at a fixed frequency to actuate the particles. Further, method may include maintaining the actuation until the particles reach respective equilibrium positions. Further, the method may include sorting the suspension into samples by extracting portions at heights within the cuvette.

Description

A METHOD AND A SYSTEM FOR SORTING PARTICLES CROSS-REFERENCE

[0001] This Application is based upon and derives the benefit of Indian Provisional Application Number 202541000587 filed on 03 January 2025, the contents of which are incorporated herein by reference.FIELD OF INVENTION

[0002] The present disclosure generally relates to manipulation, separation or sorting systems of particles with motility, and more particularly relates to a method and a system for sorting particles.BACKGROUND

[0003] Generally, particles with motility refer to externally driven or self-propelled particles, such as nano-swimmers and micro-swimmers, which include nanoscale to sub-millimeter scale objects actuated by external sources using external fields. Such particles with motility are utilized in various healthcare and biomedical applications, including targeted therapeutic delivery and microsurgery, where a population of micro-swimmers is required to exhibit substantially similar performance for a given set of drive parameters. However, performance of a nanoswimmer depends on a combined effect of intrinsic properties of the nano-swimmer. For example, in the case of a magnetic nano-swimmer, the intrinsic properties include, but are not limited to, a magnetic moment, a magnetization angle, and a geometry. Variations in any of the intrinsic properties can introduce variations in performance of the nano-swimmer, thereby resulting in undesirable inconsistencies for various applications that demand uniformity in actuation behaviour.

[0004] Propulsion of nano-swimmers occurs in a regime corresponding to low Reynolds number hydrodynamics. At such microscale conditions, a reciprocal motion is insufficient to generate net displacement in a Newtonian and incompressible medium. The reciprocal motion refers to a sequence of movements that is identical when executed in reverse order. For example, macroscopic scales and moderate to high Reynolds numbers, a scallop can achieve locomotion byslowly opening its shell and then rapidly closing it, with inertia carrying it forward during the fast-closing stroke. However, in the low Reynolds number regime, inertia is negligible and the flow is effectively time reversible. Consequently, a reciprocal stroke in which the opening and closing motions are identical but reversed in time produces no net displacement, because any displacement generated during the first part of the cycle is cancelled during the second part of the cycle. Therefore, nanoswimmers require non-reciprocal motion, such as a rotation of a helical structure, to break time-reversal symmetry and achieve propulsion under low Reynolds number conditions.

[0005] Consequently, there is a need in the art for a method and a system for sorting particles with motility to enable a controlled separation of the particles with motility based on performance variations arising from intrinsic property differences, to at least address the issues in the aforementioned prior arts.SUMMARY

[0006] This section is provided to introduce certain objects and aspects of the present disclosure in a simplified form that are further described below in the detailed description. This summary is not intended to identify the key features or the scope of the claimed subject matter.

[0007] In an aspect, the present disclosure relates to a method for sorting particles with motility. Further, the method may include receiving, by a particle sorting system, a quantity of fluid comprising one or more particles with motility. Furthermore, the method may include generating, by the particle sorting system, a rotating magnetic field using a plurality of coils. The plurality of coils may be positioned causing a strength of a rotating magnetic field decreasing along a direction opposing gravity. In addition, the method may include disposing, a cuvette. The cuvette may include a suspension of the particles in deionized water vertically within the region of the decreasing rotating magnetic field strength, with a highest field strength at a bottom of the cuvette and a lowest field strength at a top of the cuvette. Further, the method may include applying, by the particle sorting system, the rotating magnetic field at a fixed frequency to actuate the particles, causing propulsion against gravity. In addition, the method may includemaintaining, by the particle sorting system, the actuation until the particles reaches respective equilibrium positions along a height of the cuvette. At each equilibrium position a propulsive force from rotation balances gravitational force, resulting in zero translational velocity. Further, the method may include sorting, by the particle sorting system, the suspension into a plurality of samples by extracting portions at a plurality of heights within the cuvette using an injecting device.

[0008] In another aspect, the present disclosure relates to a particle sorting system for sorting particles. Further, the particle sorting system may be configured to include a field generator. Furthermore, the field generator may be configured to generate a drive field with a spatial gradient along an axis within a sorting volume. Further, the particle sorting system may be configured to include an opposing-field generator. The opposing-field generator may be configured to generate an opposing field to exert a force component along the axis counter to propulsion induced by the drive field. In addition, the particle sorting system may be configured to include a containment vessel may be positioned within the sorting volume. Further, the containment vessel may be configured to hold a suspension of the particles in a fluid medium. Further, the particle sorting system may be configured to include a controller. Further, the controller may be configured to actuate the drive field at a fixed drive parameter and maintain the opposing field at a set magnitude causing individual particles reach respective equilibrium positions along the axis where propulsion induced by the drive field balances force from the opposing field. Further, the particle sorting system may be configured to include an extraction unit. In addition, the extraction unit may be configured to withdraw fractions of the suspension from different positions along the axis corresponding to distinct equilibrium bands.

[0009] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosurewill be described and explained with additional specificity and detail with the appended figures.BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0010] The accompanying drawings, which are incorporated herein, and constitute a part of this invention, illustrate exemplary embodiments of the disclosed methods and systems in which like reference numerals refer to the same parts throughout the different drawings. Components in the drawings are not necessarily to scale; emphasis instead being placed upon clearly illustrating the principles of the present invention. Some drawings may indicate the components using block diagrams and may not represent the internal circuitry of each component. It will be appreciated by those skilled in the art that invention of such drawings includes the invention of electrical components, electronic components or circuitry commonly used to implement such components.

[0011] FIG. 1 illustrates an exemplary block diagram representation of a particle sorting system for sorting particles, according to an embodiment of the present disclosure;

[0012] FIG. 2 illustrates an exemplary structural representation of helical ferromagnetic particles, according to an embodiment of the present disclosure;

[0013] FIG. 3A illustrates an exemplary representation of actuation of the one or more nano swimmers based on the generation of a magnetic field with spatial gradient in the fluid, according to an embodiment of the present disclosure;

[0014] FIG. 3B and FIG. 3C illustrates a graphical representation of a frequency vs Speed of the one or more nano swimmers 202 based on the magnetic field with spatial gradient and step out frequency, according to an embodiment of the present disclosure;

[0015] FIG. 4A and FIG. 4B illustrate an exemplary representation of generation of magnetic flux based on generation of the rotating magnetic field with spatial gradient using the plurality of coils, according to an embodiment of the present disclosure;

[0016] FIG. 5 illustrates an exemplary representation of equilibrium positioning of one or more nano swimmers within a containment vessel, according to an embodiment of the present disclosure;

[0017] FIG. 6 illustrates an exemplary representation of a cuvette system for sorting particles with motility based on performance of the particles with motility, in accordance with an embodiment of the present disclosure;

[0018] FIG. 7 illustrate a graphical representation of determining slope and step-out frequency to determine pitch and cutoff frequency, in accordance with an embodiment of the present disclosure; and

[0019] FIG. 8 illustrates a flow chart depicting a method for sorting particles with motility, in accordance with an embodiment of the present disclosure.

[0020] The foregoing shall be more apparent from the following more detailed description of the disclosure.DETAILED DESCRIPTION

[0021] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address all of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein.

[0022] The ensuing description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth.

[0023] Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.

[0024] Also, it is noted that individual embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed but could have additional steps not included in a figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination can correspond to a return of the function to the calling function or the main function.

[0025] The word “exemplary” and / or “demonstrative” is used herein to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as “exemplary” and / or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes”,” “has,” “contains,” and other similar words are used in either the detailed description or the claims, such terms are intended to be inclusive — in a manner similar to the term “comprising” as an open transition word — without precluding any additional or other elements.

[0026] Reference throughout this specification to “one embodiment” or “an embodiment” or “an instance” or “one instance” means that a particular feature,structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0028] An objective of the present invention is to provide a method and system for sorting particles with motility based on differences in their propulsion and performance characteristics. Another objective of the present invention is to enable non-invasive, field-driven separation of motile particles without physically disturbing equilibrium conditions. Another objective of the present invention is to achieve efficient sorting of nanoscale and microscale swimmers operating in low Reynolds number regimes where viscous forces dominate inertial effects. Another objective of the present invention is to establish a predictable relationship between equilibrium position and particle performance, enabling systematic collection of particles with desired motility characteristics. Another objective of the present invention is to improve uniformity in sorted particle populations for applications requiring consistent collective behaviour, including therapeutic delivery and microsurgical applications.

[0029] Referring now to the drawings, and more particularly to FIGs. 1 through FIG. 8, where similar reference characters denote corresponding featuresconsistently throughout the figures, there are shown preferred embodiments, and these embodiments are described in the context of the following exemplary system and / or method.

[0030] FIG. 1 illustrates an exemplary block diagram representation of a particle sorting system 100 for sorting particles, according to an embodiment of the present disclosure. The particle sorting system 100 includes a field generator 102, an opposing-field generator 104, a containment vessel 106, a controller 108, an extraction unit 110, and a sensing module 112.

[0031] The particle sorting system 100 may include the field generator 102. The field generator 102 may refer to a module which may be configured to generate a drive field that induces propulsion in particles with motility. Further, the field generator 102 may include at least one coil pair, at least two orthogonal coil pairs, a triaxial coil arrangement, or an electromagnetic field-producing assembly capable of generating a rotating drive field with a spatial gradient in magnitude. Examples of the field generator 102 may include but not limited to a Helmholtz coil system, a Maxwell coil system, or a phase-shifted electromagnetic coil pair. Further, the field generator 102 may generate the drive field having the spatial gradient required to produce controlled propulsion forces in the particles with motility, in which condition the particles with motility reach equilibrium positions that vary according to performance variations arising from intrinsic property differences.

[0032] Further, the particle sorting system 100 may include the opposing-field generator 104. The opposing-field generator 104 may refer to a module configured to generate an opposing field that applies a force component counter to propulsion induced by the drive field generated by the field generator 102. Furthermore, the opposing-field generator 104 may include a gravitational force condition, an electric field, a magnetic field, a hydrodynamic field, an optical field, or a chemical field capable of providing an opposing force. In addition, the opposing-field generator 104 may establish the opposing field required to counteract the propulsion induced by the drive field, in which condition the particles with motility settle at equilibrium positions along a sorting axis when the drive field and the opposing field balance.

[0033] Furthermore, the particle sorting system 100 may include the containment vessel 106. Further, the containment vessel 106 may refer to a structure which may be configured to retain a suspension of the particles with motility in the fluid medium within a sorting volume. Examples of the containment vessel 106 may include but not limited to a cuvette, a vertically oriented vessel, or a transparent fluidic container. In addition, the containment vessel 106 may be positioned within the spatial gradient of the drive field generated by the field generator 102 and the opposing field generated by the opposing -field generator 104, in which condition the particles with motility experience combined field effects causing separation into equilibrium bands according to performance differences.

[0034] In addition, the particle sorting system 100 may include the controller 108. Further, the controller 108 may refer to a control module which may be configured to regulate operation of the field generator 102, the opposing -field generator 104, the extraction unit 110, and the sensing module 112. Examples of the controller 108 may include but not limited to a microcontroller, an Arduino controller, a programmable logic controller, an embedded processor, or a computing device executing stored instructions. Further, the controller 108 may maintain the fixed drive parameter applied through the field generator 102. Further, the controller 108 may maintain the magnitude of the opposing field generated by the opposing -field generator 104, and coordinates extraction and sensing functions to achieve sorting according to equilibrium positions of the particles with motility.

[0035] Further, the particle sorting system 100 may include the extraction unit 110. Further, the extraction unit 110 may refer to a module which may be configured to withdraw fractions of the suspension from different heights within the containment vessel 106. Examples of the extraction unit 110 may include but not limited to a sampling needle, a syringe-based extraction device, or a liquidhandling mechanism may be configured for vertical positioning. In addition, the extraction unit 110 may collect samples from distinct equilibrium regions along the sorting axis, in which condition the extracted fractions correspond to groups of the particles with motility exhibiting different performance values. Further, the term distinct equilibrium regions may refer to spatially separated regions within thecontainment vessel 106 at which individual particles with motility may reach steady-state equilibrium positions. Further, the steady-state equilibrium positions may occur when a propulsion force induced by the drive field generated by the field generator 102 balances an opposing force generated by the opposing -field generator 104, resulting in substantially zero translational velocity of the particles with motility along a sorting axis. Further, the distinct equilibrium regions may correspond to different positions along the sorting axis and may be separated based on differences in equilibrium height or location within the containment vessel 106. Furthermore, the term performance values may refer to quantitative or qualitative measures associated with propulsion behaviour of the particles with motility under application of the drive field and the opposing field. The performance values may be determined based on equilibrium point data corresponding to the steady-state equilibrium positions of the particles with motility within the containment vessel 106. The performance values may represent variations arising from intrinsic property differences of the particles with motility and may be used to differentiate and sort the particles with motility into the distinct equilibrium regions.

[0036] Further, the particle sorting system 100 may include the sensing module 112. Further, the sensing module 112 may refer to an imaging and detection module. The imaging and detection module may be configured to track trajectories and equilibrium positions of the particles with motility within the containment vessel 106. Examples of the sensing module 112 may include but not limited to an optical camera, an imaging sensor, or a microscope-based detection unit. Further, the sensing module 112 may detect steady-state equilibrium positions and may provide positional data to the controller 108, in which condition the controller 108 may regulate sorting and extraction according to the equilibrium positions of the particles with motility.

[0037] In an exemplary embodiment, the particle sorting system 100 for sorting particles may include the field generator 102. The field generator 102 may be configured to generate the drive field with the spatial gradient along an axis within a sorting volume. The term sorting volume may refer to a spatial region inwhich the drive field generated by the field generator 102 and the opposing field generated by the opposing -field generator 104 overlap and interact to influence motion of the particles with motility. The sorting volume may include a region within which the containment vessel 106 may be positioned such that the suspension of the particles with motility may be exposed to a spatial gradient of the drive field along an axis and to the opposing field exerting a force component along the axis. Further, the opposing-field generator 104 may be configured to generate an opposing field to exert a force component along the axis counter to propulsion induced by the drive field. Further, the term force component may refer to a portion of a force vector acting along a defined axis within the sorting volume. Further, the force component may represent a directional contribution of the opposing field generated by the opposing-field generator 104 that acts counter to propulsion induced by the drive field generated by the field generator 102. Furthermore, the containment vessel 106 may be positioned within the sorting volume. Further, the containment vessel 106 may be configured to hold a suspension of the particles in the fluid medium. Further, the particle sorting system 100 may be configured to the controller 108. The controller may be configured to actuate the drive field at fixed drive parameter. The term fixed drive parameter may refer to a drive-related operating parameter of the drive field generated by the field generator 102 that may be maintained at a substantially constant value during a sorting operation. The fixed drive parameter may include at least one of a drive frequency, a drive amplitude, a phase relationship, or a temporal waveform characteristic associated with the drive field. Further, the controller 108 may maintain the opposing field at a set magnitude causing individual particles reach respective equilibrium positions along the axis at which propulsion induced by the drive field balances force from the opposing field. Further, the particle sorting system 100 may be configured to an extraction unit 110. The extraction unit 110 may be configured to withdraw fractions of the suspension from different positions along the axis corresponding to distinct equilibrium band. Further, the term distinct equilibrium bands may refer to spatially separated regions within the containment vessel 106 that extend across a finite range along an axis within the sorting volume. Further, the distinct equilibrium bands may correspondto collections of equilibrium positions at which particles with motility experience a balance between propulsion induced by the drive field generated by the field generator 102 and a force component generated by the opposing-field generator 104. In addition, the distinct equilibrium bands may be separated based on differences in position along the axis and may represent groupings of the particles with motility having different performance values,

[0038] In one embodiment, the field generator 102 may include at least two orthogonal coil pairs arranged relative to the containment vessel 106. The at least two orthogonal coil pairs may be driven with a pre-defined degree phase offset to generate a rotating magnetic field. Further, the rotating magnetic field may exhibit a magnitude that decreases monotonically with height relative to gravity within the containment vessel 106. Furthermore, the monotonically decreasing magnitude of the rotating magnetic field may establish a spatial gradient of the drive field along an axis within the sorting volume, in which condition particles with motility may experience different propulsion forces at different heights, thereby enabling formation of distinct equilibrium bands. In addition, the term pre-defined degree phase offset may refer to a fixed angular phase difference that may be maintained between drive signals applied to the at least two orthogonal coil pairs of the field generator 102.

[0039] In one embodiment, the opposing-field generator 104 may include a gravitational force acting on the particles with motility along the axis within the sorting volume. In the embodiment, the controller 108 may position the containment vessel 106 relative to the field generator 102 such that the rotating drive field generated by the field generator 102 decreases in magnitude in a direction opposite to gravity. The positioning of the containment vessel 106 may cause the particles with motility to experience a balance between propulsion induced by the rotating drive field and the gravitational load, thereby enabling the particles with motility to reach equilibrium positions along the axis. Further, the term gravitational force may act on the particles with motility due to gravitational acceleration. Further, the gravitational force may act uniformly along the axis within the sorting volume and may provide the force component generated by theopposing-field generator 104 that counteracts propulsion induced by the drive field generated by the field generator 102.

[0040] In one embodiment, the containment vessel 106 may be a vertically oriented cuvette. In the embodiment, the controller 108 may position the containment vessel 106 relative to the field generator 102 such that a maximum drive field magnitude occurs at a bottom region of the containment vessel 106 and a minimum drive field magnitude occurs at a top region of the containment vessel 106. Further, the positioning of the containment vessel 106 may cause the particles with motility to experience a spatial gradient of the drive field along the axis, thereby enabling separation of the particles with motility based on equilibrium positions. Further, the term bottom region may refer to a lower portion of the containment vessel 106 along the axis within the sorting volume. The bottom region may correspond to a region of the containment vessel 106 that may be positioned closer to the field generator 102 and exposed to a higher magnitude of the drive field generated by the field generator 102. Furthermore, the term minimum drive field magnitude may refer to a lowest value of the drive field magnitude experienced by the particles with motility within the containment vessel 106 along the axis. The minimum drive field magnitude may occur at a region of the containment vessel 106 that may be positioned farther from the field generator 102 along the axis. In addition, the top region may refer to an upper portion of the containment vessel 106 along the axis within the sorting volume. The top region may correspond to a region of the containment vessel 106 that may be positioned farther from the field generator 102 and exposed to the minimum drive field magnitude.

[0041] In one embodiment, the containment vessel 106 may be a cuvette positioned above the coils of the field generator 102 at a pre-defined distance. Further, the pre-defined distance may be selected such that a field strength of the drive field generated by the field generator 102 at the bottom region( near drive field generator) of the containment vessel 106 corresponds to minimum step-out field of the batch of particles with motility, being sorted, at the applied fixed drive parameter. In addition, the positioning of the containment vessel 106 may cause theparticles with motility to experience reduced propulsion capability at the top region, thereby contributing to formation of equilibrium positions along the axis. Further, the term maximum step-out field may refer to a maximum magnitude of the drive field at which the particles with motility are capable of maintaining synchronous rotational motion with the applied drive field at the applied fixed drive parameter, but may not (do not) propel. The maximum step-out field may correspond to a threshold field magnitude beyond which the particles with motility are unable to sustain propulsion to counter an opposing force.

[0042] In an embodiment, the particle sorting system 100 may be disposed within a magnetized environment (the term ‘magnetized environment interchangeably referred as environment), and one or more field driving sources may be associated with the particle sorting system 100. Further, a user may be associated with the particle sorting system 100 via a communication device coupled via a network to the particle sorting system 100. The particle sorting system 100 may include the magnetic manipulation mechanism, which may include an image capturing device, such as a camera, used to capture results of operation of the particle sorting system 100, including imaging of an object after manipulation, and a light source. Further, the light source projects light onto the object, and the illumination forms part of an optical setup used to capture or observe the object. Further the driving field with a spatial gradient may exert an upward force on particles within the particle sorting system 100. Further, the driving field with the spatial gradient may be generated using the one or more field driving sources for positioning or manipulation. Further, an opposing field may act downward on the particles, opposing the driving field with the spatial gradient. The driving field with the spatial gradient may compensate for or balance effects of the opposing field acting on the object. The one or more field driving sources may generate the driving field with the spatial gradient around the object. By adjusting current supplied to the one or more field driving sources, a driving force acting on the object may be controlled, enabling precise manipulation of a position of the object. A lens may receive light from the light source, which passes through the object and may be thenfocused by the lens as part of an imaging system used to study behaviour of the object optically.

[0043] In an embodiment, the particle sorting system 100 may be configured to receive a sample quantity of fluid from the user. The sample quantity of fluid may include deionized water containing one or more particles with motility. Further, the one or more particles with motility may include one or more nano swimmers and one or more micro swimmers. The particles with motility may include externally driven particles and self-propelled particles. Further, the particle sorting system 100 may be configured to generate the driving field with the spatial gradient in the sample quantity of fluid using the one or more field driving sources associated with the particle sorting system 100. Further, the driving field with the spatial gradient may include an electric field with a spatial gradient, a magnetic field with a spatial gradient, a hydrodynamic field with a spatial gradient, a chemical field with a spatial gradient, and an optical field with a spatial gradient. Further, the one or more field driving sources may include one or more coils for generating a magnetic field with a spatial gradient and one or more electrodes for generating an electric field with a spatial gradient. Furthermore, the particle sorting system 100 may be configured to apply the opposing field acting on the one or more particles with motility in the sample quantity of fluid. Further, the opposing field may include the electric field with or without a gradient, a magnetic field with a gradient, a hydrodynamic field with or without a gradient, a chemical field with a gradient, and an optical field with a gradient. Furthermore, the particle sorting system 100 may be configured to determine equilibrium point data of the one or more particles with motility based on the driving field with the spatial gradient and the opposing field. The equilibrium point data corresponds to the point at which effects of the driving field with the spatial gradient and the opposing field balance each other. Furthermore, the particle sorting system 100 may be configured to determine performance values of the one or more particles with motility based on the equilibrium point data. The performance values correspond to differences among equilibrium point data of the one or more particles with motility.Subsequently, the particle sorting system 100 may be configured to sort the one or more particles with the motility based on the performance values.

[0044] FIG. 2 illustrates an exemplary structural representation of helical ferromagnetic particles 200, according to an embodiment of the present disclosure.

[0045] Further, part (A) of FIG.2 illustrates a microscopic image of the one or more particles with motility, (the term one or more particles with motility interchangeably referred as one or more nano swimmers 202). Further, the one or more nano swimmers 202 exhibit a helical structure formed by silicon dioxide structures 204 with iron layers 206 deposited on the silicon dioxide structures 204. Furthermore, a propulsion direction may represent a direction of movement of the one or more nano swimmers 202 when the one or more nano swimmers 202 may be actuated by the rotating magnetic field generated by the field generator 102 of the particle sorting system 100. Further, the helical structure of the one or more nano swimmers 202 may enable the one or more nano swimmers 202 to convert rotational motion into translational motion along the propulsion direction 200.

[0046] Furthermore, part (B) of FIG. 2 illustrates a schematic representation of the one or more nano swimmers 202 showing structural composition of the one or more nano swimmers 202. Further, the schematic representation shows the silicon dioxide structures 204 forming a helical body with the iron layers 206 deposited on the silicon dioxide structures 204. Further, the iron layers 206 may provide ferromagnetic properties to the one or more nano swimmers 202, enabling the one or more nano swimmers 202 to respond to the rotating magnetic field. Furthermore, the helical configuration of the silicon dioxide structures 204 combined with the ferromagnetic iron layers 206 may enable the one or more nano swimmers 202 to generate propulsion when subjected to the rotating magnetic field.

[0047] In an embodiment, the one or more nano swimmers 202 may be fabricated on a silicon wafer using a vapour deposition technique called Glancing Angle Deposition. Further, the one or more nano swimmers 202 may include the helical-shaped silicon dioxide structures 204 with the iron layers 206, in which the iron layers 206 render the one or more nano swimmers 202 ferromagnetic.Furthermore, when the rotating magnetic field may be applied by the field generator 102, the one or more nano swimmers 202 rotate about a longitudinal axis of the one or more nano swimmers 202, in which condition the helical structure may convert the rotational motion into translational motion along the propulsion direction 200, enabling the one or more nano swimmers 202 to propel through the fluid medium in a controlled manner.

[0048] FIG. 3A illustrates an exemplary representation of actuation of the one or more nano swimmers 202 based on the generation of the magnetic field with spatial gradient in the fluid, according to an embodiment of the present disclosure.

[0049] In an embodiment, the one or more nano swimmers 202 may be actuated using the driving field with spatial gradient such as the magnetic field with spatial gradient (as shown in FIG. 3 A) generated by a two axis Helmholtz coil. Further, the magnetic moment of the one or more nano swimmers 202 may follow the rotating magnetic field with spatial gradient to generate rotational movement of the one or more nano swimmers, which may lead to propulsion of the one or more nano swimmers, Further, the rotating magnetic field with spatial gradient may be generated using one or more field driving sources such as a pair of (two or more coils. Further, the two or more coil pairs may be placed such that their center lies on the vertices of an imaginary square. Further, the diagonally opposite coils may be connected in series such that current in one coil is clockwise while the current in another coil is anticlockwise. The field comes out of one coil and enters another making the field horizontal in the center of the square. Further, the pairs of coils are 90° out of phase which creates a rotating magnetic field with spatial gradient in the plane of the one or more coils. The FIG. 3A configuration may create rotating magnetic field with spatial gradient, at the center of the square, with gradient in strength of field as we go away from the two or more coils.

[0050] Similarly, the drive field with spatial gradient may also be of any form that results in a taxis behaviour like electric, magnetic, acoustic, chemical, etc. For example, the driving field with spatial gradient may be a gradient electric field, and the opposing field could be a gradient magnetic field. So, at equilibrium the equations may be defined as shown in equation 1 and 2 below:v = 0, ) — 0 and F — qE — m B... Equation 1mAB = qE z')... Equation 2Here, m is the magnetic moment of nano swimmer, B is the gradient magnetic field, q is the charge on the swimmer,and E is the electric field.

[0051] FIG. 3B and FIG. 3C illustrates a graphical representation of a frequency of rotating magnetic field vs Speed of the one or more nano swimmers202 based on the rotating magnetic field with spatial gradient and step out frequency determination based on the frequency vs speed representation of the one or morenano swimmers 202, in accordance with an embodiment of the present disclosure.

[0052] In an embodiment, the velocity of the one or more nano swimmers202 may depend on the frequency of the rotation of the one or more nano swimmers202. In an embodiment, the frequency of the rotation of the one or more nano swimmers 202 may depend on the frequency of the rotating magnetic field withspatial gradient. Let us consider an example where the one or more nano swimmers202 may perform a tumbling motion, i.e. rotation about its short axis, below a frequency ( / 21). In an embodiment, the tumbling motion may be a reciprocal motionand, therefore, does not result in any net displacement. This is represented as shownin equation 3 below:v— 0; flB<............ Equation 3where v represents the net displacement of the one or more nano swimmers 202,and represents the frequency of rotation of the one or more nano swimmers202.

[0053] Further in an embodiment, beyond 21, the one or more nano swimmers 202 may perform a precession motion, and velocity of the one or morenano swimmers 202 may increase with the increasing frequency of rotation. Further,the precession angle of the one or more nano swimmers 202 may decrease as thefrequency of rotation increases, which may be represented as shown in equation 4below:v= p * cos(sin-1(ap)) * flB; < flB< fl2. Equation 4Here, ap= Sl l S1B, where aprepresents the precision angle, and p represents geometric pitch of the one or more nano swimmers 202.

[0054] In addition, beyond step-out frequency (f22) (as shown in FIG. 3C),the one or more nano swimmers 109 may randomly switch between the tumblingmotion and propulsion. In an embodiment, the tumbling motion and propulsion aretwo stable states that the one or more nano swimmers 202 may jump between dueto thermal noise. The f j^and2depend on the magnetic moment, magnetizationangle, geometry, fluid viscosity, and the field strength of the generated rotating magnetic field with spatial gradient, as shown in equations 5 and 6 below:m B sin(0m} n=________________. Equation 5Fssin2(0m) cos2(0m) fl2= mB2+. Equation 6-J Is Yiwhere,, ysare friction coefficients around long and short axis respectively; 0mis the angle of magnetization from short axis of the one or more nano swimmers and B is the field strength of the generated rotating magnetic field.

[0055] Furthermore, the one or more nano swimmers 202 may follow therotating magnetic field to a step-out frequency (I22). At the step-out frequency (I22),the one or more nano swimmers 202 may not process and reaches maximumvelocity for the field strength of the rotating magnetic field, which may lead to propulsion of the one or more nano swimmers 202. Further in an embodiment,beyond the step-out frequency (122), the drag may be significant for the one or morenano swimmers 202 to follow the magnetic field with spatial gradient, and hencethe velocity of the one or more nano swimmers 202 may decrease with furtherincrease in the frequency of rotation of the one or more nano swimmers 202, whichmay represented as shown in equation 7 below:v = p * ^ / 2B— — I2| J; > tl2.... Equation 7

[0056] The fabrication method of the one or more nano swimmers 202 may give rise to variability in the properties of the one or more nano swimmers 202, like magnetic moment, magnetization angle, and geometry. The performance / dynamics of the one or more nano swimmers 202 may depend on the combination of these properties. Further, collective behaviour applications of the one or more nano swimmers 202 may require uniformity in performance.

[0057] In an embodiment, the one or more nano swimmers 202 may see different field strengths of the rotating magnetic field with spatial gradient at different heights. Therefore, the one or more nano swimmers 202 with different properties will reach step-out at different heights, because the step-out frequency (fl2) depends on the applied magnetic field strength, which may decrease as a function of height. Further, the one or more nano swimmers 202, beyond step-out frequency ( / 22), may not follow the magnetic field with spatial gradient and rotates slower. Further, the slower rotation means reduced thrust to propel against gravity. As illustrated in FIG. 3B, the velocity of the one or more nano swimmers 202 as a function of frequency of rotation (T2B), where the step-out frequency (f]2) of the one or more nano swimmers 202 may decrease as a function of strength of rotating magnetic field with spatial gradient.

[0058] FIG. 4A and FIG. 4B illustrate an exemplary representation of generation of magnetic flux 400 based on generation of the rotating magnetic field with spatial gradient using the plurality of coils, according to an embodiment of the present disclosure. Further, FIG. 4A and FIG. 4B may represent a COMSOL simulation of the rotating magnetic field with the spatial gradient generated by the field generator 102 of the particle sorting system 100. Furthermore, the rotating magnetic field with the spatial gradient may be generated using the plurality of coils of the field generator 102. Further, the plurality of coils may include pairs of coils positioned at vertices of a square. Furthermore, the plurality of coils may be placed such that a center of each coil of the plurality of coils lies on the vertices of animaginary square. Further, diagonally opposite coils of the plurality of coils are connected in series such that current in one coil is clockwise while current in another coil is anticlockwise. Furthermore, the rotating magnetic field comes out of one coil and enters another coil making the rotating magnetic field horizontal in a center of the square. Further, the pairs of coils are 90 degrees out of phase which creates the rotating magnetic field with the spatial gradient in a plane of the plurality' of coils. Furthermore, the configuration of the plurality of coils creates the rotating magnetic field with the spatial gradient in magnitude of rotating magnetic field at the center of the square with gradient in strength of the rotating magnetic field as distance increases away from the plurality of coils.

[0059] Further, in an embodiment, a strength of the rotating magnetic field with the spatial gradient may decrease upon moving away from the plurality of coils in a direction perpendicular to the plane of the plurality of coils. Furthermore, the decreasing strength of the rotating magnetic field establishes the spatial gradient along an axis within a sorting volume of the particle sorting system 100. Further, the spatial gradient causes the rotating magnetic field strength to decrease along a direction opposing gravity, in which condition a highest field strength occurs at a bottom of the containment vessel 106 and a lowest field strength occurs at a top of the containment vessel 106.

[0060] FIG. 5 illustrates an exemplary representation of equilibrium positioning of one or more nano swimmers 202 within the containment vessel 106, according to an embodiment of the present disclosure.

[0061] In an embodiment, the one or more nano swimmers 202 reach a height within the containment vessel 106 at which thaist due to rotation of the one or more nano swimmers 202 balances gravity acting on the one or more nano swimmers 202. Further, the one or more nano swimmers 202 may reach an equilibrium point at the height. Furthermore, at the equilibrium point (as shown in part (A) of FIG. 5), the one or more nano swimmers 202 may rotate about a long axis of the one or more nano swimmers 202, but the thrust may be insufficient to overpower gravity. Further, the one or more nano swimmers 202 remain at the height corresponding to the equilibrium point. Furthermore, a force due to gravityand torque due to an external rotating magnetic field with spatial gradient can be related to translational velocity and rotational velocity of the one or more nano swimmers 202 using a 6x6 friction tensor matrix as shown in equation 8 below.------- F'cv + rrc... Equation 8

[0062] At an equilibrium point 502 (as shown in part (A) of FIG.5), the translational velocity is zero and the two counteracting forces, that are force due to the rotating magnetic field with spatial gradient and the opposing field, balance each other. For example, in case of the one or more m gnetic nano swimmers 202, weight of the one or more nano swimmers 202 equals the force due to rotating magnetic field with spatial gradient. The strength of the rotating magnetic field with spatial gradient may decrease as a function of height, and the opposing field may be a force due to gravity, which may be defined as shown in equation 8 and 9 below:v = 0 and F = Mg... Equation 8Mg — rcm(z)... Equation 9Here, Fcis the coupling friction coeff icient, is the actual rotation of the one or more nano swimmers, andM is the mass of the one or more nano swimmers

[0063] In an embodiment, the opposing field can be of any form like electric field with or without gradient, magnetic field with gradient, hydrodynamic field with or without gradient, electromagnetic field with or without gradient, etc. For example, in case of the one or more magnetic nano swimmers 202, the opposing field could be a force due hydrodynamic flow. In that case at equilibrium the equations may be defined as shown in equation 10 and 11:v = 0 and F = —1pCDvreiA.... Equation 10—pCDvrei2A — rcm(z)... Equation 11Here, vreiis the relative velocity of swimmer wrt to fluid, f low, Fcis the coupling friction coefficient, at is the actual rotation of swimmer,is the cross section area,p is density of the fluid, and CDis the drag coefficient.

[0064] Further, the drag force for a sphere-shaped particle (at low Reynolds number regime) may be defined as shown in equation 12:F = 6nrivrei... Equation 12

[0065] Furthermore, another, example of an opposing field may be a magnetic field with gradient. In that case, at equilibrium equation may be defined as shown in equation 13 and 14:v — 0 and F — m B... Equation 13mAB = Tcui(z)... Equation 14Here, rcis the coupling friction coefficient, ) is the actual rotation of swimmer, m is the magnetic moment of the one or more nano swimmers,and B is the gradient magnetic field.

[0066] Further, the part (B) of FIG.5 and part (C) of FIG. 5 illustrate an exemplary representation of tumbling motion and propulsion 504 of the one or more nano swimmers 202.

[0067] In an embodiment, beyond a step-out frequency, the one or more nano swimmers 202 may tumble and propel randomly, also referred to as tumbling motion and propulsion 504, as shown in part (B) of FIG. 5. Further, the step-out frequency corresponds to a cutoff frequency at which the one or more nano swimmers 202 are unable to maintain synchronous rotation with the rotating magnetic field generated by the field generator 102. Furthermore, since the tumbling motion 504 may be reciprocal, the one or more nano swimmers 202 may fall due to gravity. Further, as the one or more nano swimmers 202 fall some (distance or) height, the one or more nano swimmers 202 may experience a larger rotating magnetic field. Furthermore, the step-out frequency of the one or more nano swimmers 202 may increase, causing the one or more nano swimmers 202 topropel against gravity with increased thrust. Further, the one or more nano swimmers 202 may remain at a region within a height range due to falling and propelling randomly, as shown in part (C) of FIG. 5.

[0068] FIG. 6 illustrates an exemplary representation of a cuvette system 602 for sorting particles with motility based on performance of the particles with motility, in accordance with an embodiment of the present disclosure.

[0069] Further, FIG. 6 shows an environment 600 containing the cuvette system 602. Furthermore, the cuvette system 602 may correspond to the containment vessel 106 of the particle sorting system 100. Further, the cuvette system 602 may be 1 mm thick, 1.25 cms wide, and 4.5 cms long. Furthermore, the cuvette system 602 may include a sample quantity of the fluid which may further include one or more nano swimmers 202 in the fluid. Further, the cuvette system 602 may be placed vertically in a region above the field generator 102. Furthermore, due to a rotating magnetic field with spatial gradient generated by the field generator 102, with rotation in a plane perpendicular to gravity, the one or more nano swimmers 202 inside the cuvette system 602 may propel against gravity.

[0070] Further, the cuvette system 602 may be placed such that a magnitude of the rotating magnetic field with the spatial gradient decreases from a bottom to a top of the cuvette system 602, in which a maximum field strength occurs at the bottom of the cuvette system 602. Furthermore, placement of the cuvette system 602 or field strengths may be such that all the one or more nano swimmers 202 may be beyond a cutoff point of the one or more nano swimmers 202 for every height in the cuvette system 602. Further, the cutoff point corresponds to a step-out frequency at which the one or more nano swimmers 202 lose synchronous rotation with the rotating magnetic field.

[0071] In an embodiment, for a fixed magnetic field strength, the step-out frequency of the one or more nano swimmers 202 depends on magnetic moment, angle of magnetization, and friction coefficient of the one or more nano swimmers 202. Furthermore, the one or more nano swimmers 202 may be separated based on at least one of magnetic moment, angle of magnetization, friction coefficient, or a combination of the magnetic moment, the angle of magnetization, and the frictioncoefficient. Furthermore, after the one or more nano swimmers 202 reach the equilibrium point, the sample quantity of the fluid may include the one or more nano swimmers 202 can be separated into multiple samples based on height.

[0072] FIG. 6 illustrates an exemplary representation of a cuvette system 602 for sorting particles with motility based on performance of the particles with motility, in accordance with an embodiment of the present disclosure.

[0073] Further, the FIG. 6 may represent separation into four samples designated as SI, S2, S3, and S4 as a function of height. Furthermore, an extraction device may be used to collect the samples sequentially from top to bottom. Further, the extraction device corresponds to the extraction unit 110 of the particle sorting system 100. Furthermore, as height decreases within the cuvette system 602, the step-out frequency of the one or more nano swimmers 202 decreases as a function of height.

[0074] Further, the cuvette system 602 may be placed such that magnitude of the rotating magnetic field corresponds to minimum step-out field of the batch of particles with motility, being sorted, for a set drive frequency at the top bottom of the cuvette system 602, and magnitude of field may highest at the bottom of the cuvette system 602.

[0075] FIG. 7 illustrate a graphical representation of determining slope and step-out frequency 700 to determine pitch and cutoff frequency, in accordance with an embodiment of the present disclosure.

[0076] Further, part (A) of FIG. 7 may disclose cutoff frequency determination for the one or more nano swimmers 202. Furthermore, part (A) of FIG. 7 may represent a velocity versus actuation frequency plot in which the cutoff frequency corresponds to a maximum velocity after fitting. Further, the cutoff frequency represents a point at which velocity may be maximum before decreasing. Furthermore, the cutoff frequency may be a parameter to quantify performance of the one or more nano swimmers 202.

[0077] Further, part (B) of FIG. 7 may disclose pitch determination for the one or more nano swimmers 202. Furthermore, part (B) of FIG. 7 may represent the velocity versus actuation frequency plot in which a slope of a linear region givesthe pitch of the one or more nano swimmers 202. Further, the slope of a linear part of the plot may be the pitch of the one or more nano swimmers 202. Furthermore, the pitch is a parameter to quantify performance of the one or more nano swimmers 202.

[0078] In an embodiment, collected samples (as illustrated in FIG. 6) may be characterized by determining slope and step-out frequency from the velocity versus actuation frequency plot. Further, the velocity of the one or more nano swimmers 202 as a function of actuation frequency, also referred to as frequency of rotation, may be calculated by tracking and detecting the one or more nano swimmers 202 using basic thresholding-based image processing. Furthermore, the pitch and the cutoff frequency are two parameters to quantify performance of the one or more nano swimmers 202.

[0079] Further, as shown in part (A) of FIG. 7 and part (B) of FIG. 7, the plots show values of cutoff frequency and pitch of the one or more nano swimmers 202 for each sample SI, S2, S3, and S4 collected at different heights from the cuvette system 602, as shown in FIG. 6, after sorting. Furthermore, the plots demonstrate that there is a difference in average cutoff frequencies of samples collected at different heights from the cuvette system 602.

[0080] Further, the step-out frequency of the one or more nano swimmers 202 for each sorted group may be calculated to obtain statistics. Furthermore, a mean step-out frequency shows a trend as a function of height at which a sample quantity was collected. Further, the mean step-out frequency may higher for a sample from a top of the cuvette system 602 and decreases for samples collected at lower heights. Furthermore, the trend implies that the one or more nano swimmers 202 with a larger step-out frequency for a given field strength reach equilibrium at a higher height in the cuvette system 602. Further, the one or more nano swimmers 202 are sorted based on performance values corresponding to the step-out frequency as a function of height.

[0081] Further, error bars in the plots represent standard error of mean. Furthermore, deviation can be due to inherent variation as samples are collected for a height range of 1 cm. Further, deviation can be verified by collecting samplesfrom smaller regions or depths of 0.5 cms, which should cause decrease in standard deviation. Furthermore, the deviation depends on resolution of depth at which samples are collected. Further, another cause of deviation could be actual sample collection using the extraction device disturbing equilibrium by creating flows in the cuvette system 602 or due to thermal fluctuations.

[0082] Further, part (C) of FIG. 7 an embodiment in which the medium used for sorting may include the liquid medium, the porous medium, or a combination thereof. In an exemplary embodiment, the medium may include one or more layers of a porous medium disposed within a liquid medium, for example a porous layer immersed in water. Examples of the porous medium may include anodized aluminium oxide, silica gel, hydrogel, or similar porous materials. Further, the inclusion of the porous medium or the one or more porous layers may reduce or prevent convective flows generated within the cuvette system 602, which may otherwise adversely affect the sorting process.

[0083] In an exemplary embodiment, the porous medium may be arranged to divide the cuvette system 602 into a plurality of sections, where each section corresponds to a batch of nano swimmers that reach equilibrium within the respective section. Further, a pore diameter of the porous medium may be selected based on a size of particles being sorted, such that particles having sizes smaller than the pore diameter may pass through the porous medium. Accordingly, the porous medium may additionally function as a size filter, thereby further refining the sorting process. Further, to increase sorting resolution, a gradient of the magnetic field may be increased by positioning the cuvette system 602 closer to one or more coils, thereby operating within a higher-gradient region as indicated in part (C) of FIG.7. In an exemplary embodiment, a region between dotted lines may correspond to a higher magnetic field gradient region, while a solid line may represent a top of the coil. Additionally, alternative coil configurations may be employed to further increase the magnetic field gradient and thereby enhance separation resolution of the nano swimmers.

[0084] FIG. 8 illustrates a flow chart depicting a method 800 for sorting particles with motility, in accordance with an embodiment of the present disclosure.

[0085] At step 802, the method 800 may include receiving, by the particle sorting system 100, the quantity of fluid may include one or more particles with motility.

[0086] At step 804, the method 800 may include receiving, by the particle sorting system 100, the quantity of fluid comprising one or more particles with motility.

[0087] At step 806, the method 800 may include disposing the cuvette. The cuvette may include the suspension of the particles in deionized water vertically within the region of the decreasing rotating magnetic field strength, with the highest field strength at a bottom of the cuvette and the lowest field strength at the top of the cuvette.

[0088] At step 808, the method 800 may include applying, by the particle sorting system 100, the rotating magnetic field at a fixed frequency to actuate the particles, causing propulsion against gravity.

[0089] At step 810, the method 800 may include maintaining, by the particle sorting system 100, the actuation until the particles reaches respective equilibrium positions along the height of the cuvette. At each equilibrium position the propulsive force from rotation balances gravitational force, resulting in zero translational velocity. In an embodiment, the drive field and the opposing field are not limited to a rotating magnetic field and gravity, respectively, and may alternatively or additionally comprise electric, hydrodynamic, optical, acoustic, other field-based forces, and the like.

[0090] At step 812, the method 800 may include sorting, by the particle sorting system 100, the suspension into a plurality of samples by extracting portions at the plurality of heights within the cuvette using an injecting device. Further, the term "injecting device" may refer to a fluid extraction and injection mechanism configured to withdraw fractions of the suspension from different positions along an axis within the containment vessel 106. Further, the injecting device corresponds to the extraction unit 110 of the particle sorting system 100. Furthermore, examples of the injecting device may include but are not limited to a sampling needle, a syringe-based extraction device, a pipette, a liquid-handling mechanism configuredfor vertical positioning, or an automated fluid sampling system. Further, the injecting device may be configured to collect samples from distinct equilibrium regions along a sorting axis within the containment vessel 106, in which condition extracted fractions correspond to groups of the one or more particles with motility exhibiting different performance values. Furthermore, the injecting device may be actuated by the controller 108 to withdraw portions at a plurality of heights within the containment vessel 106 to sort the suspension into a plurality of samples.

[0091] Further, the method 800 may include establishing, by the particle sorting system 100, the spatial gradient in the drive field for inducing propulsion in the particles. Further, the method 800 may include applying, by the particle sorting system 100, the opposing field exerting force counter to the propulsion direction. Furthermore, the method 800 may include suspending, by the particle sorting system 100, the particles in the medium within the gradient region causing drive field strength varying inversely with position along a propulsion axis. Further, the method 800 may include actuating, by the particle sorting system 100, the drive field at the fixed parameter until particles reach equilibrium positions where propulsive thrust balances opposing force. Further, the method 800 may include collecting, by the particle sorting system 100, separated fractions from distinct positions along the propulsion axis.

[0092] Further, the method 800 may include the drive field corresponding to a chemical gradient for chemotactic particles, with hydrodynamic flow as the opposing field. Further, the method 800 may include the drive field corresponding to the rotating electric field gradient for electrotactic particles, with at least one of gravitational- based force and charge-based force as the opposing field.

[0093] Further, the method 800 may include generating the rotating magnetic field. Further, the method 800 may include, positioning, by the particle sorting system 100, the plurality of coils at vertices of the square with centres separated by a pre-defined distance. Further, the method may include connecting, by the particle sorting system 100, diagonally opposite coils in series causing to flow current clockwise in one coil and anticlockwise in the opposing coil of each pair of plurality of coils. Further, the method 800 may include driving, by theparticle sorting system 100, each pair of plurality of coils with the pre-defined degree phase difference to generate rotation in a plane perpendicular to gravity.

[0094] Furthermore, the method 800 may include tracking, by the particle sorting system 100, positions of each of the plurality of particles in each of the sorted sample using the image processing technique. Further, the image processing technique may refer to the method 800 or set of computational operations applied to a digital image in order to enhance, analyse, transform, or extract meaningful information from the image. Further, the method 800 may include measuring, by the particle sorting system 100, translational velocity as the function of actuation frequency, based on the tracked positions. Further, the method 800 may include determining, by the particle sorting system 100, step-out frequency as the cutoff where velocity peaks after linear increase, based on the measured translational velocity. Further, the method 800 may include computing, by the particle sorting system 100, mean step-out frequency for each of the sorted sample. The sorted samples from higher heights exhibit higher mean step-out frequencies.

[0095] Furthermore, the method 800 may include determining, by the particle sorting system 100, equilibrium point data of the one or more particles having motility based on the driving field having the spatial gradient and the opposing field. Further, the method 800 may include determining, by the particle sorting system 100, performance values of the one or more particles having motility based on the equilibrium point data. Further, the method 800 may include sorting, by the particle sorting system 100, the one or more particles having motility based on the performance values.

[0096] Furthermore, the method 800 may include the particles with motility. The motility may include at least one of externally driven particles, self-propelled particles, nano-swimmers, and micro-swimmers.

[0097] Furthermore, the method 800 may include the particles with motility exhibit taxis behaviour comprising at least one of magneto-taxis, electro-taxis, chemotaxis, rheo-taxis, and photo-taxis. The sorting is based on the spatial gradient in the driving field corresponding to the taxis behaviour and the opposing field.

[0098] Furthermore, the method 800 may include the drive field. The drive field include at least one of rotating magnetic field, rotating electric field, optical intensity gradient, chemical concentration gradient, and hydrodynamic shear gradient. The opposing field includes at least one of gravitational field, electric or magnetic static field gradient, chemical counter-gradient, and controlled flow field.

[0099] Furthermore, the method 800 may include the opposing field. The opposite field may include at least one of an electric field with gradient, an electric field without a gradient, a magnetic field with a gradient, a hydrodynamic field with a gradient, a hydrodynamic field without a gradient, a chemical field with a gradient, and an optical field with a gradient.

[0100] Furthermore, the method 800 may include the equilibrium point data corresponds to positions at which effects of the driving field having the spatial gradient and the opposing field balance for each of the one or more particles having motility.

[0101] Furthermore, the method 800 may include the performance values are determined based on differences in the equilibrium point data among the one or more particles having motility.

[0102] Further, the technical advantages of the particle sorting system 100 may enable sorting of the one or more particles with motility based on performance values rather than individual properties. Furthermore, the performance values may represent a combined effect of multiple intrinsic properties of the one or more particles with motility. Further, for magnetic nano swimmers 202, the performance values may depend on a combination of magnetic moment, angle of magnetization, and geometric properties. Furthermore, the particle sorting system 100 may sorts the one or more particles with motility based on the performance values that directly correspond to operational behaviour under actuation conditions.

[0103] Further, the particle sorting system 100 may operate by reaching a steady-state equilibrium condition Further, unlike sorting techniques that rely on thermal equilibrium, the particle sorting system 100 may drive the system out of equilibrium and reaches the steady-state equilibrium in which counteracting forces balance each other. Furthermore, the steady-state approach may ensure that the oneor more particles with motility eventually reach respective equilibrium positions regardless of initial distribution or time taken.

[0104] Further, the particle sorting system 100 may universally be applicable to particles exhibiting any form of taxis behaviour. Furthermore, the taxis behaviour includes at least one of magneto-taxis, electro-taxis, chemotaxis, rheotaxis, photo-taxis, and acoustic-taxis. Further, the particle sorting system 100 may achieve sorting by establishing a spatial gradient in the drive field corresponding to the taxis behaviour and applying the opposing field. Furthermore, the universal applicability may enable the particle sorting system 100 to sort externally driven particles, self-propelled particles, nano-swimmers, and micro-swimmers using appropriate field combinations.

[0105] Further, the particle sorting system 100 may provide flexibility in selection of the drive field and the opposing field. Furthermore, the drive field includes at least one of the rotating magnetic fields, the rotating electric field, the optical intensity gradient, the chemical concentration gradient, the hydrodynamic field gradient, and the acoustic field gradient. Further, the opposing field includes at least one of the gravitational fields, the electric field with or without a gradient, the magnetic field with a gradient, a hydrodynamic field with or without the gradient, a chemical field with the gradient, and an optical field with a gradient. Furthermore, the flexibility enables adaptation of the particle sorting system 100 to different particle types and operational requirements.

[0106] Further, the particle sorting system 100 may discloses scalability for production applications. Furthermore, the particle sorting system 100 may sort chemically manufactured particles that may be produced in large quantities but exhibit significant variation in properties. Further, the particle sorting system 100 may enable separation of chemically made nano swimmers based on performance values that depend on geometric and other property variations. Furthermore, the scalability enables practical application in manufacturing processes requiring uniform performance characteristics.

[0107] Furthermore, the one or more particles with motility self-organize into distinct equilibrium bands based on the performance values under influence ofthe drive field with the spatial gradient and the opposing field. Furthermore, the particle sorting system 100 may not require real-time tracking and individual control of each particle during the sorting process.

[0108] Further, the particle sorting system 100 may enable sorting at nanoscale and microscale. Furthermore, the particle sorting system 100 may operate effectively for nano-swimmers and micro-swimmers in the low Reynolds number regime. Further, the low Reynolds number regime may be characterized by negligible inertial effects and dominance of viscous forces. Furthermore, the particle sorting system 100 may utilize non-reciprocal motion of helical structures to achieve propulsion and sorting in the low Reynolds number regime.

[0109] Further, the particle sorting system 100 may provide improved uniformity for collective behaviour applications. Furthermore, collective behaviour applications may require one or more motile particles to perform similarly for a given set of drive parameters. Further, the particle sorting system 100 may enable selection of sorted samples having narrow performance distributions. Furthermore, the improved uniformity may enhance effectiveness of collective behaviour applications, including targeted therapeutic delivery and microsurgery applications.

[0110] Further, the particle sorting system 100 may enable non-invasive optical characterization of sorted samples. Furthermore, the sensing module 112 may track trajectories and equilibrium positions of the one or more motile particles within the containment vessel 106. Further, the sensing module 112 may utilize image processing techniques to determine velocity as a function of actuation frequency. Furthermore, the non-invasive characterization may enable verification of sorting effectiveness without disturbing equilibrium conditions.

[0111] Further, the particle sorting system 100 may demonstrate trend correlation between equilibrium height and performance values. Furthermore, a mean step-out frequency may be higher for samples collected from top regions of the containment vessel 106 and may decrease for samples collected at lower heights. Further, the trend correlation may validate the sorting mechanism and may enable prediction of performance characteristics based on equilibrium position.Furthermore, the predictable relationship between position and performance may enable systematic collection of samples having desired characteristics.

[0112] The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, etc., of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope and spirit of the disclosed embodiments. Also, the words “comprising”, “having”, “containing”, and “including”, and other similar forms are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.

[0113] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

Claims

CLAIMS1. A method (800) for sorting particles with motility, comprising:receiving, by a particle sorting system (100), a quantity of fluid comprising one or more particles with motility;generating, by the particle sorting system (100), a rotating magnetic field using a plurality of coils, wherein the plurality of coils is positioned causing a strength of a rotating magnetic field decreasing along a direction opposing gravity;disposing, a cuvette comprising a suspension of the particles in deionized water vertically within the region of the decreasing rotating magnetic field strength, with a highest field strength at a bottom of the cuvette and a lowest field strength at a top of the cuvette;applying, by the particle sorting system (100), the rotating magnetic field at a fixed frequency to actuate the particles, causing propulsion against gravity;maintaining, by the particle sorting system (100), the actuation until the particles reaches respective equilibrium positions along a height of the cuvette, wherein at each equilibrium position a propulsive force from rotation balances gravitational force, resulting in zero translational velocity; andsorting, by the particle sorting system (100), the suspension into a plurality of samples by extracting portions at a plurality of heights within the cuvette using an injecting device.

2. The method (800) as claimed in claim 1, further comprising:establishing, by the particle sorting system (100), a spatial gradient in a drive field for inducing propulsion in the particles;applying, by the particle sorting system (100), an opposing field exerting force counter to the propulsion direction;suspending, by the particle sorting system (100), the particles in a medium within the gradient region causing drive field strength varying inversely with position along a propulsion axis;actuating, by the particle sorting system (100), the drive field at a fixed parameter until particles reach equilibrium positions where propulsive thrust balances opposing force; andcollecting, by the particle sorting system (100), separated fractions from distinct positions along the propulsion axis.

3. The method (800) as claimed in claim 2, further comprising at least one of:the drive field corresponding to a chemical gradient for chemotactic particles, with hydrodynamic flow as the opposing field; andthe drive field corresponding to a rotating electric field gradient for electrotactic particles, with at least one of gravitational- based force and charge-based force as the opposing field.

4. The method (800) as claimed in claim 1, wherein generating the rotating magnetic field comprises:positioning, by the particle sorting system (100), a plurality of coils at vertices of a square with centres separated by a pre-defined distance;connecting, by the particle sorting system (100), diagonally opposite coils in series causing to flow current clockwise in one coil and anticlockwise in the opposing coil of each pair of plurality of coils; anddriving, by the particle sorting system (100), each pair of plurality of coils with a pre-defined degree phase difference to generate rotation in a plane perpendicular to gravity.

5. The method (800) as claimed in claim 1, further comprising:tracking, by the particle sorting system (100), positions of each of the plurality of particles in each of the sorted sample using an image processing technique;measuring, by the particle sorting system (100), translational velocity as a function of actuation frequency, based on the tracked positions;determining, by the particle sorting system (100), step-out frequency as a cutoff where velocity peaks after linear increase, based on the measured translational velocity; andcomputing, by the particle sorting system (100), mean step-out frequency for each of the sorted sample, wherein the sorted samples from higher heights exhibit higher mean step-out frequencies.

6. The method (800) as claimed in claim 1, further comprising:determining, by the particle sorting system (100), equilibrium point data of the one or more particles having motility based on the driving field having the spatial gradient and the opposing field;determining, by the particle sorting system (100), performance values of the one or more particles having motility based on the equilibrium point data; andsorting, by the particle sorting system (100), the one or more particles having motility based on the performance values.

7. The method (800) as claimed in claim 1, wherein the particles with motility comprise at least one of externally driven particles, self-propelled particles, nano-swimmers, and micro-swimmers.

8. The method (800) as claimed in claim 1, wherein the particles with motility exhibit taxis behaviour comprising at least one of magneto-taxis, electro-taxis, chemo-taxis, rheo-taxis, and photo-taxis, and wherein the sorting is based on the spatial gradient in the driving field corresponding to the taxi’s behaviour and the opposing field.

9. The method (800) as claimed in claim 2, wherein the drive field comprises at least one of rotating magnetic field, rotating electric field, optical intensity gradient, chemical concentration gradient, and hydrodynamic shear gradient, and wherein the opposing field comprises at least one of gravitational field, electric or magnetic static field gradient, chemical counter-gradient, and controlled flow field.

10. The method (800) as claimed in claim 2, wherein the opposing field comprises at least one of an electric field with gradient, an electric field without a gradient, a magnetic field with a gradient, a hydrodynamic field with a gradient, a hydrodynamic field without a gradient, a chemical field with a gradient, and an optical field with a gradient.

11. The method (800) as claimed in claim 6, wherein the equilibrium point data corresponds to positions at which effects of the driving field having the spatial gradient and the opposing field balance for each of the one or more particles having motility.

12. The method (800) as claimed in claim 6, wherein the performance values are determined based on differences in the equilibrium point data among the one or more particles having motility.

13. A particle sorting system (100) for sorting particles, comprising:a field generator (102) configured to generate a drive field with a spatial gradient along an axis within a sorting volume;an opposing-field generator (104) configured to generate an opposing field to exert a force component along the axis counter to propulsion induced by the drive field;a containment vessel (106) positioned within the sorting volume, configured to hold a suspension of the particles in a medium;a controller (108) configured to actuate the drive field at a fixed drive parameter and maintain the opposing field at a set magnitude causing individual particles reach respective equilibrium positions along the axis where propulsion induced by the drive field balances force from the opposing field; andan extraction unit (110) configured to withdraw fractions of the suspension from different positions along the axis corresponding to distinct equilibrium bands.

14. The particle sorting system (100) as claimed in claim 13, wherein the field generator (102) comprises at least two orthogonal coil pairs driven with a pre-defined degree phase offset to generate a rotating magnetic field, with magnitude decreasing monotonically with height relative to gravity within the containment vessel (106).

15. The particle sorting system (100) as claimed in claim 13, wherein the opposing-field generator (104) comprises a gravitational force acting on the particles along the axis, and the controller positions the containment vessel (106) causing the rotating drive field decreases in magnitude in the direction opposite to gravity.

16. The particle sorting system (100) as claimed in claim 13, wherein the containment vessel (106) is a vertically oriented cuvette and the controller positions the cuvette causing the maximum drive field magnitude occurs at a bottom region and a minimum drive field magnitude occurs at a top region.

17. The particle sorting system (100) as claimed in claim 16, wherein the cuvette is positioned above the coils at a pre-defined distance causing the field strength at the bottom corresponds to a minimum step-out field of the batch of particles being sorted at the applied fixed frequency.

18. The particle sorting system (100) as claimed in claim 13, further comprising a sensing module (112) configured to track particle trajectories and compute steady-state equilibrium positions along the axis, and a separator configured to actuate the extraction unit to collect fractions based on sensed equilibrium bands.

19. The particle sorting system (100) as claimed in claim 13, wherein the medium comprises at least one of a porous medium, a combination of porous medium, a liquid medium, and a layers of porous media, wherein the porous medium comprises at least one of an anodized aluminium oxide, a silica gel, and a hydrogel, wherein the porous medium and the layered porous media is configured to inhibit convective flows within the cuvette, and divides the cuvette into a plurality of sections corresponding to equilibrium positions of batches of swimmers, wherein the porous medium comprises a pore diameter selected based on a sizeof particles to be sorted to permeate particles smaller than the pore diameter, for providing secondary size-based filtration.

20. The particle sorting system (100) as claimed in claim 13, wherein the magnetic field gradient is increased to increase a sorting resolution by positioning the cuvette within a high-gradient region between the coils, and an alternative coils generate increased magnetic field gradients for increasing a separation resolution.

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