A fleet and layer of magnetic particles

Abstract

Provided is a magnetic system comprising a fleet of magnetic particles and a magnetic layer. The magnetic particles are configured such that their position, conformation, orientation and configuration is manipulated by external magnetic fields and that they maintain their configuration in the absence of a magnetic field.

Description

A FLEET AND LAYER OF MAGNETIC PARTICLESFIELD OF THE INVENTION

[0001] The presently disclosed subject matter relates to a system comprising a fleet and layer of magnetic particles. The fleet of magnetic particles is configured to move through a medium, or a network of channels and carry out an action at a target location. The fleet is also configured to change configuration during the course of travelling through various media and channels. The invention is also directed to magnetic layers that change state under the influence of an external magnetic field. The invention relates to the systems, methods of production and methods of operation thereof.BACKGROUND

[0002] The use of magnetic particles in various applications has seen significant growth. However, controlling magnetic particles is sometimes a challenging task due to the difficulties associated with manipulating their motion using external fields. Take, for example, ferromagnetic liquids. While their shape can be influenced by external fields, maintaining a stable configuration is not easy due to their fluid nature and surface tension. When considering groups of magnetic particles, manipulating individual particles within the group is challenging due to strong interactions between individual magnets. Furthermore, magnetic shielding within groups of magnetic particles prevents ‘access’ of external magnetic field to influence motion within a magnetic fleet.

[0003] On the other hand, weakly interacting magnetic particles present a different problem. Utilizing fleets of weakly interacting magnetic particles often requires a fluid holding medium which interacts with those magnetic particles often making their behavior, under the influence of an external field, unpredictable. Furthermore, in the absence of external magnetic fields, systems of weakly interacting magnetic particles are unable to predictably orient themselves, often resulting in Brownian- like motion and stochastic behavior.

[0004] One goal of the present invention is to provide a system wherein a fleet of magnetic particles can be manipulated at the level of the individual magnetic particle. Furthermore, by selecting the shape of the magnetic core and shell one can control not only the interaction between individual magnetic particles but the behavior and configuration of the magnetic fleet. Another goal of the present invention is to control the number of inter-particle configurations to ensure that the configuration of magnetic particles in the fleet is predictable and that the orientation is maintained even when an external magnetic field is removed.

[0005] One goal of the present invention is to provide a magnetic layer whereby an external magnetic field is used to manipulate the conformation, orientation, configuration, location and orientation of the magnetic particles comprised therein. A further goal includes ensuring that the magnetic particles (at least in part) maintain their configuration even after an external magnetic field is removed, unlike the case of ferromagnetic fluids.SUMMARY

[0006] In some embodiments the invention provides a magnetic field comprising: a plurality of magnetic particles wherein each magnetic particle comprises at least one core and a shell; wherein each magnetic particle is in contact with at least one other magnetic particle in the plurality of magnetic particles; wherein the position of at least one magnetic particle within the plurality of magnetic particles is configured to change in response to an external magnetic field; and wherein the plurality of magnetic particles at least partially retain their configuration after the external magnetic field has been removed.

[0007] In some embodiments the plurality of magnetic particles comprises between 2 and 1 ,000,000,000 magnetic particles. In some embodiments the magnetic particles in the magnetic fleet further comprise a cavity disposed inside the magnetic particle wherein the magnetic core is comprised therein. In some embodiments the center of the core or the cavity, or a combination thereof, is not positioned at the center of the magnetic particle. In some embodiments the core is configured to change position inside the magnetic particle. In some embodiments the shape of the at least one core, the shell has a shape, the cavity, or any combination thereof, is selected from a list comprising: random shape, spheroid, cylinder, tetrahedron, cube, octahedron, dodecahedron, icosahedron, cone, pyramid and rod or any combinations thereof. In some embodiments the at least one core comprises between 1 to 99% of the volume of the magnetic particle. In some embodiments the at least one core comprises a magnetic material. In some embodiments the magnetic material comprises: permanent magnet, ferromagnet, iron, aluminum, cobalt, nickel, gadolinium, dysprosium, neodymium, samarium, terbium, molybdenum, copper, europium, holmium, ceramic magnet and alnico magnet or any combinations thereof. In some embodiments the ceramic magnet comprises: strontium ferrite, barium ferrite, titanium ferrite, yttrium ferrite, yttrium iron garnet andlithium ferrite or any combination thereof. In some embodiments the shell comprises a polymer. In some embodiments the polymer is selected from: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), nylon, polycarbonate (PC), acrylonitrile-butadiene- styrene (ABS), polyurethane (PU), polyvinylidene fluoride (PVDF), perfluoroethylene (PFE), polymethyl methacrylate (PMMA), polyimide (PI), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyetheretherketone (PEEK) and silicone or any combinations thereof. In some embodiments the shell comprises a metal. In some embodiments the metal is selected from: copper, titanium, tungsten, 416 stainless steel, nitinol, and an alloy or any combination thereof. In some embodiments the size of at least one dimension of the magnetic particles ranges from between 0.01 to 5 mm. In some embodiments the magnetic particles further comprise at least one coating disposed on the at least one core, the shell or a combination thereof. In some embodiments the plurality of magnetic particles are configured together in any of the following formations selected from: a chain, a ring, an arrow, single layer, multi-layers and a cluster or any combination thereof. In some embodiments at least one magnetic particle in the plurality of magnetic particles comprises at least one active substance. In some embodiments the magnetic fleet further comprises an encapsulating membrane which encapsulates the plurality of magnetic particles. In some embodiments the membrane is flexible, dissolvable, porous or a combination thereof. In some embodiments the at least one active substance is additionally disposed between the magnetic particles and the membrane. In some embodiments the active substance is in solid or liquid form or a combination thereof. In some embodiments the active substance comprises at least one therapeutic compound. In some embodiments the at least one therapeutic compound is selected from: analgesic, antibiotic, antiviral, antifungals, antidepressant, anti-inflammatory, antioxidant, anticoagulant, antihistamines, antihypertensives, anticonvulsants, antibodies, antidiabetics, antipsychotics, antacids, cancer drugs, corticosteroids, diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs), intravenous fluids, saline solution, dextrose solution, Ringer’s lactate solution, plasma- lyte, buffer, electrolytes, proton pump inhibitors, relaxants, sedatives, statins, steroids and vitamin supplements or any combination thereof.

[0008] In some embodiments the invention provides a magnetic fleet system comprising: the magnetic fleet as described herein; and at least one external magnetic field.

[0009] In some embodiments the invention provides a magnetic layer, comprising:a plurality of magnetic particles wherein each magnetic particle comprises at least one core and a shell; an upper plane and a lower plane configured to hold the plurality of magnetic particles therebetween, wherein the position of at least one magnetic particle within the plurality of magnetic particles is configured to change in response to an external magnetic field; and wherein the plurality of magnetic particles at least partially retain their configuration after the external magnetic field has been removed.

[0010] In some embodiments the magnetic layer further comprises a fluid medium disposed between the upper plane and the lower plane. In some embodiments the fluid medium comprises any of the following selected from: water, glycerol, glycol, gel, oil and lubricant or any combination thereof. In some embodiments the magnetic layer further comprises a plurality of spacers disposed in between the upper plane and the lower plane. In some embodiments the upper plane, the lower plane, or a combination thereof comprise a polymer. In some embodiments the polymer is selected from: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), nylon, polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polyurethane (PU), polyvinylidene fluoride (PVDF), perfluoroethylene (PFE), polymethyl methacrylate (PMMA), polyimide (PI), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyetheretherketone (PEEK) and silicone or any combinations thereof. In some embodiments the gap between the upper plane and the lower plane ranges between 0.5 and 50mm.

[0011] In some embodiments this invention provides a magnetic layer system comprising: the magnetic layer as disclosed herein; and at least one external magnetic field.

[0012] In some embodiments this invention provides a method of operating a magnetic fleet system comprising: a. providing the magnetic fleet system as disclosed herein; b. injecting the magnetic fleet at an entry point of an environment; c. operating the at least one external magnetic field to manipulate the location, orientation and configuration of the magnetic fleet to a target location within the environment; d. carrying out an action at the target location; e. optionally carrying out steps ‘c’ and ‘d’ at least one more time; andf. retrieving the magnetic fleet by operating the at least one external magnetic field via an exit point.

[0013] In some embodiments the environment is selected from: a living organism and a body of liquid. In some embodiments the entry point and the exit point are the same. In some embodiments the target location is selected from: brain, lungs, blood vessels, stomach, intestines, reproductive organs, urinary system and esophagus. In some embodiments the action comprises: delivering an active substance, releasing an active substance, making an incision, widening a channel, unblocking a channel, blocking a channel, massaging, scrubbing, polishing and cleaning.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0015] Figure 1 shows a 2D schematic illustrations of magnetic particles where the cores vary in shape and size.

[0016] Figure 2 shows a 2D schematic illustrations of magnetic particles with cores of different shapes and wherein the cores are coated with an additional layer. Figures 2A and 2B show configurations where the core is placed in the center of the magnetic particle whereas Figures 2C and 2D show asymmetric configurations. Figures 2E to 2H show various embodiments of magnetic particles comprising a cavity and wherein the magnetic core moves within the cavity. In some aspects, the magnetic core, the cavity, or a combination thereof, are off-center from the center of the magnetic particle.

[0017] Figure 3 shows a schematic illustration of a magnetic particle further comprising an active substance. Figure 3A shows a magnetic particle with the active substance attached adjacently to it. Figure 3B shows the active substance encompassing the magnetic particle. Figure 3C shows the active substance encompassing the magnetic particle and a further additional layer or encapsulation membrane. Figure 3D is the same as Figure 3C but additionally comprises an active substance within the encapsulating membrane. Figure 3E shows two magnetic particles (i.e., this can be extended to any number of magnetic particles to form a fleet) each being encompassed by an active substance and encased within an encapsulating membrane. Figure 3F shows the same as Figure 3E but additionally comprises an active substance within the encapsulating membrane.

[0018] Figure 4 is a 2D schematic illustration of magnetic particles held between an upper and lower plane. Figure 4A shows a spheroidal core and spheroidal shell; Figure 4B shows a cylindrical core and cuboidal shell; Figure 4C shows a cuboidal core and pentagonal shell; Figure 4D shows a triangular core and hexagonal shell.

[0019] Figure 5 is a 3D schematic illustration of various embodiments of magnetic particles comprising a cavity within the shell. Figure 5A shows a cylindrical cavity core and spherical shell; Figure 5B shows a larger cylindrical cavity core (than Figure 5A) and a spherical shell; Figure 5C shows a cuboidal cavity core and spherical shell; Figure 5D shows a spherical cavity core and spherical shell. The cavity core in Figure 5 represents either the cavity which comprises the core or the magnetic core itself.

[0020] Figure 6 shows a schematic illustration of a fleet of magnetic particles passing through a narrow channel by means of an external magnet.

[0021] Figure 7 shows a schematic illustration of a fleet of encapsulated magnetic particles, passing through a narrow channel.

[0022] Figure 8 shows a schematic illustration of various configurations of 10 magnetic particles forming a magnetic fleet. Figure 8A shows an arrowhead shape comprising sphereshaped particles. Figure 8B shows a chain shape comprising sphere-shaped particles. Figure 8C shows a rectangular shape comprising sphere-shaped particles. Figure 8D shows a ring shape comprising sphere-shaped particles. Figure 8E shows magnetic particles with different shapes coalescing together in a clump.

[0023] Figure 9 shows the packing of a fleet of hexagonal magnetic particles (with rectangular magnets as the core). Although magnetic particles are 3-dimensional, the schematic illustration shows them in 2-dimensions for the purposes of examples alone.

[0024] Figure 10 shows magnetic particles comprising more than one magnetic core. Figure 10A shows a basic schema. Figure 10B shows an elongated magnetic particle comprising two cores i.e., a ‘real life’ example of Figure 10A. Figure 10C shows a magnetic fleet comprising dual-core magnetic particles, in a ring formation.

[0025] Figure 11 shows a magnetic layer confined between an upper and a lower plane. An external magnet is used to manipulate the conformation, orientation and configuration of the magnetic particles within the magnetic layer.

[0026] Figure 12 shows various embodiments of magnetic layers.

[0027] For simplicity and clarity of illustration, elements shown in the figures are not necessarily drawn to scale, and the dimensions of some elements may be exaggerated relativeto other elements. In addition, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.DETAILED DESCRIPTION

[0028] The magnetic fleet generally comprises a plurality of magnetic particles. In various embodiments the magnetic particles comprise a core and a shell. In some embodiments the core comprises magnetic material. As described herein, the present invention is directed towards a magnetic fleet comprising a plurality of magnetic particles. The present invention is also directed towards a magnetic layer comprising a plurality of magnetic particles confined between an upper and a lower plane, that can move under the influence of an external magnetic field.

[0029] Some of the following considerations are disclosed:- The structure, shape and composition of components of the magnetic particles;- The position / configuration of the magnetic component within the magnetic particle;- The medium within which magnetic particles are disposed;- The friction between magnetic particles;- The friction between the magnetic particles and the medium within which the magnetic particles are disposed;- The nature and application of the external magnetic field and its coupling to the magnetic particles.

[0030] The role of these factors will become apparent when various embodiments and examples are expanded upon. Generally, the packing of a plurality of platonic solids has specific configurations, comprising local minima, when the system is at rest i.e., stable minima. A general example is now provided for the purpose of illustration: A sphere can interact with another sphere equally at every point on its surface and a collection of spheres will pack together in any angular orientation e.g., marbles at rest in a bowl. However, a collection of cubes (each with 6 sides) will tend to assemble, when at rest in a bowl, with each side facing another side of a neighboring cube. In an ideal packing, a collection of cubes can form a tight 3D structure with no (or minimal) gaps therebetween. This is in contrast with a collection of marbles which, even with tight packing, will form gaps between nearest-neighbor marbles. Thus, the selection of the platonic shape of a particle can provide an additional degreeof freedom in controlling the orientation of particles and their orientation and configuration with nearest neighbors.

[0031] Furthermore, as will become apparent, the selection of the shape and position of a magnetic components within a shell formed of a platonic solid can further provide additional control for the position and orientation of individual magnetic particles within a fleet or layer of magnetic particles.

[0032] Two primary goals of the present invention is to:1) Provide a system wherein individual magnetic particles, and a fleet / layer of magnetic particles (i.e., a “plurality of particles”) respond predictably to an external magnetic field; and2) Provide a system where the orientation and configuration of magnetic particles within a fleet / layer of magnetic particles retain their orientation once the external magnetic field has been withdrawn or removed.Magnetic Particles Comprised within Magnetic Fleets and Magnetic Layers100033] Figure 4 shows four separate two-dimensional schematic depictions of magnetic particles 100. It should be noted that Figure 4 is a simplified 2D representation, or crosssection, of a 3D structure. The specific 2D shapes and conformations depicted herein are for the purposes of example alone. For example, Figure 4 show embodiments of a magnetic particle 100 comprising a core magnet 104 and a shell 103. In one embodiment the term “magnetic particle” refers to any particle that is magnetic. In one embodiment a magnetic particle comprises a core magnet and a shell. As used herein “core magnet” or “core” refers to any core that comprises magnetic material or material that can be magnetized. Furthermore, the core is magnetic. In some embodiments the terms “magnetic particle” and simply “particle” are used interchangeably. The core magnet 104 and the shell 103 are not limited to a particular 3D shape. In one embodiment the core magnet 104 has a shape selected from a list comprising: random shape, spheroid, cylinder, tetrahedron, cube, octahedron, dodecahedron, icosahedron, cone, pyramid and rod or any combinations thereof. In one embodiment the core magnet 104 has the shape of a platonic object. In one embodiment the shell 103 has a shape selected from a list comprising: random shape, spheroid, cylinder, tetrahedron, cube, octahedron, dodecahedron, icosahedron, cone, pyramid and rod or any combinations thereof. In one embodiment the shell 104 has the shape of a platonic object. In some embodiments, the shape of the core magnet 104 and the shell 103 are the same. In some embodiments, the shape of the core magnet 104 and the shell 103 are not the same. It is notedthat the shapes do not need to be idealized representations of those shapes. In real world applications, some shapes may deviate from the idealized shapes that they were fabricated to be. As such, when referring to the shapes of certain objects, it is understood that any shape can also refer to its approximate shape or to shapes that are substantially similar. For example, the fabricated shape of a sphere may deviate from its idealized spherical shape by ±1%, ±5%, ±10%, ±20% or 50%. The term “random shape” refers to any unconventional shape that is not easily described by a standard geometry. Furthermore, and in some embodiments, the core or shell, or both, comprises an asymmetric shape. In other embodiments, the core or shell, or both comprise a symmetric shape.

[0034] In some embodiments, any combination of shapes for the core 104 and shell 103 can be used. Figure 4A shows a round core (e.g., spherical) and a round shell (e.g., spherical). Figure 4B shows a cylindrical core and a square shell (e.g., a cuboidal shell). Figure 4C shows a square core (e.g., cuboidal) and a pentagonal shell. Figure 4D shows a triangular core (e.g., pyramidal, conical) and a hexagonal shell. In one embodiment, the magnetic particle comprises more than one magnetic core. Correspondingly, and in one embodiment, the shell comprises more than one core cavity.

[0035] The volume of the core and the shell within a magnetic particle 100 can vary. In one embodiment the core comprises between 1 to 99% of the volume of the magnetic particle 100. In one embodiment the core comprises between 1 to 50% of the volume of the magnetic particle. In one embodiment the core comprises between 20 to 40% of the volume of the magnetic particle. In one embodiment the core comprises between 40 to 60% of the volume of the magnetic particle. In one embodiment the core comprises between 60 to 80% of the volume of the magnetic particle. In one embodiment the core comprises between 80 to 99% of the volume of the magnetic particle 100. Figures ID to IF illustrate how the magnetic core 104 can occupy different amounts of the magnetic particle 100. Where the total volume of the magnetic particle 100 remains the same, the magnetic core 104 gradually gets larger from Figure ID (smallest) to Figure IF (largest). The reason for selecting a magnetic core / shell arrangement in this manner, is the extent of the strength of the magnetic field at the surface of the magnetic particle 100. Where the magnetic core is buried deeper within the shell (e.g., Figure ID) the strength of the magnetic field at the surface is lower. Similarly Figures 1A to 1C show a cuboidal magnetic core 104 of different sizes. Figure 1A shows a cuboidal magnetic core 104 which is small and therefore the magnetic field at the surface is lower than Figures IB and 1C. In contrast, the cuboidal magnetic core 104 of Figure 1C is largest and extends almost to the edge of the shell 103. As such, the field strength at the surface at eitherpole (N, S) is stronger than in Figures 1A or IB. In some embodiments the magnetic core at least partially protrudes through the shell at least at one point 109. In one embodiment the north pole, the south pole, or a combination thereof, protrude from the shell. As will become clear throughout, the magnetic core 104 can be placed off-center from the center of the magnetic particle 100. In is noted that the magnetic particles in Figure 1 can include additional layers that are not show in the figures. For example, an adhesive layer between the core 104 and the shell 103 can secure the shell in place. Furthermore, as will be described, the shell can further comprise a coating (not shown).

[0036] One aspect of the present invention is to ensure that magnetic fleets can move in response to an external magnetic field. As such, the distance of the magnetic core 104 to the surface of the shell 103 is a crucial factor in manipulating how magnetic particles 100 behave and move. Thus, in some embodiments, the magnetic core 104 is comprised within a cavity inside the shell 106. The cavity is referred to interchangeable as the “cavity” and the “core cavity”, whether it comprises the magnetic core within it or not. In some embodiments the cavity 106 is larger in volume than the volume of the magnetic core 104. This facilitates the movement of the magnetic core 104 within the cavity (and hence within the magnetic particle). Figure 2E shows a shell 103, core 104 and cavity 106, wherein the magnetic core 104 is not at the center of the shell 103. Thus, the magnetic core 104 is free to move within the cavity 106 and, depending upon the location of the external magnetic field, will move accordingly. Figure 2E shows a spherical cavity 106 placed at the center of the shell 103 (and also the magnetic particle 100). The north side of an external magnet (not shown) causes the magnetic core to move to the bottom left side of the cavity 106. In some embodiments the cavity 106 is off center from the shell. In some embodiments, the shape of the shell 103, magnetic core 104 and cavity 106 are each selected from: random shape, spheroid, cylinder, tetrahedron, cube, octahedron, dodecahedron, icosahedron, cone, pyramid and rod or any combinations thereof. Any platonic shape can be used for any of the shell 103, magnetic core 104 and cavity 106, in some embodiments. Figure 2F shows the magnetic core 104 move towards the bottom of the cavity 106. In contrast with the spherical configuration of Figure 2E, the cuboidal core of Figure 2F is restricted in that the position of the magnetic core cannot flip due to limitations on the space of the cavity 106. In some embodiments, the cavity is large enough for the magnetic core to flip in a manner that both poles can be present on the surface of the cavity at either end.

[0037] The ability to ‘lock’ the position of the magnetic core 103 within the magnetic particle 100, provides a manner of limiting the number of discrete positions that the magneticcore can take. For example, if the magnetic core 104 can only point along one axis, then its ability to interact with other magnetic particles is limited to those axes alone. However, if the magnetic core 104 is spherical as shown in Figures 2E and 2G, then the direction of the magnetic field can be in any direction, as manipulated by the external magnet, since the magnetic core 104 can rotate and position itself at any point of the inside of the cavity 106. Whereas for Figure 2E, the strength of the magnetic field at the surface of the magnetic particle 100 can be the same at each end (depending on the conformation of the magnetic core), the magnetic field strength at the surface of the magnetic particle 100 for Figure 2G will not always be the same, given that the magnetic core 104, and cavity 106, are off-center from the shell 103.

[0038] In some embodiments the magnetic particle 100 comprises a core magnet. In some embodiments the magnetic particle 100 does not comprise a shell. In some embodiments the magnetic particle comprises a core magnet and an encapsulation. For example, a core magnet can be encapsulated by a film, thin film, ink, paint or any other substance or coating that ensures that the magnetic particle 100 can rotate. In another embodiment the magnetic particle 100 comprises a coated core magnet. In another embodiment the magnetic particle consists of a coated core magnet. In some embodiments the coating, or encapsulation, is rough, increasing the friction of the magnetic particle.

[0039] In some embodiments the magnetic particle is at least partially coated with an additional material. In some embodiments the magnetic particle is at least partially coated with a coating.

[0040] The magnetic particle 100 can be comprised of various materials, examples of which are now disclosed. In some embodiments the core magnet 104 comprises a magnetic material. As described herein “magnetic material” refers to any material that is magnetic. In some embodiments the magnetic material comprises: a permanent magnet or a ferromagnet or a combination thereof. In one embodiment the magnetic material comprises: a hard magnet or a soft magnet, or a combination thereof. Non-limiting examples of magnetic materials are those which comprise any of the following selected from: iron, aluminum, cobalt, nickel, gadolinium, dysprosium, neodymium, samarium, terbium, molybdenum, copper, europium, holmium, ceramic magnet and alnico magnet or any combinations thereof. Non-limiting examples of permanent magnets include: neodymium-iron-boron (NdFeB), samarium-cobalt (SmCo), alnico, ceramic (ferrite) and bonded magnets. In some embodiments the magnetic material comprises an alloy. In one embodiment the core comprises a ceramic magnet. Nonlimiting examples of ceramic magnets include: strontium ferrite, barium ferrite, titaniumferrite, yttrium ferrite, yttrium iron garnet and lithium ferrite or any combination thereof. In one embodiment the core comprises iron.

[0041] In a magnetic particle 100, the core magnet 104 is surrounded by the shell 103. The shell can be made of any material, some examples of which are now disclosed. In one embodiment the shell comprises a polymer. In one embodiment the shell comprises plastic. In one embodiment the shell comprises a dielectric material. In another embodiment the shell consists of a polymer. In another embodiment the shell comprises more than one polymer. Non-limiting examples of polymers include: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), nylon, polycarbonate (PC), aery lonitrile-butadiene- styrene (ABS), polyurethane (PU), polyvinylidene fluoride (PVDF), perfluoroethylene (PFE), polymethyl methacrylate (PMMA), polyimide (PI), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyetheretherketone (PEEK) and silicone or any combinations thereof. In some embodiments the shell comprises: an epoxy, an encapsulation gel, paint, ink or acrylics. In some embodiments the magnetic particle further comprises a photoactive material.

[0042] The shell can also comprise a metal, such as a non-magnetic metal, a weakly magnetic metal or an alloy. Non-limiting examples of metals comprised within the shell include: copper, titanium, tungsten, 416 stainless steel, nitinol, and an alloy or any combination thereof.

[0043] In some embodiments the shell further comprises at least one additional coating that at least partially covers the shell. In one embodiment the magnetic particle further comprises at least one additional coating. For example, the additional coating may comprise an agent which decreases degradation in various ways. This may protect the surface and subsequently the magnetic particles disposed within. This additional agent may imbue the surface to be: heat resistant, weathering resistant, water resistant, light-bleaching resistant (i.e., lightfast), corrosion resistant, rust resistant, etc.

[0044] In some embodiments the shell comprises a material which is a lubricant. In some embodiments the shell further comprises a material which comprises a lubricant. In some embodiments the lubricant is disposed on the surface of the shell. In various embodiments of the invention, the magnetic particles are configured to move through liquid media. As such, the surface of the magnetic particle (i.e., the shell 103) comprises a configuration that is compatible with high mobility through those media e.g., low friction surface. In some embodiments the surface of the shell 103 is smooth. With regards to ease of moving throughthe media “smooth” is considered any type of surface that enables low friction movement. This may be enabled by the material of the shell, its roughness / smoothness, its shape, aerodynamics / hydrodynamics, etc. In some embodiments the surface of the shell is configured to increase friction. For example, making the surface rough.

[0045] The size of the magnetic particle may vary according to various considerations which will become apparent. For example, the size of the magnetic particle will change according to its shape, the size and strength of the magnet disposed within, the thickness and materia] composition of the shell, magnetic shielding, material composition of the matrix (upper and lower planes), etc. For example, in an embodiment where the magnetic particle needs to rotate more freely the following may be used: a shell shape with fewer facets / sides, a low-friction material (for the shell and / or matrix), a stronger external magnet and a magnet that is better coupled to magnetic material, or any combination thereof. There are also differences with particles that are of different sizes. As will become apparent, the range of sizes of magnetic particles is from the micron to millimeter range. Thus, certain parameters like surface friction, which do not scale linearly with the radius of a particle, are adjusted for with each application. Furthermore, a single magnetic particle will have various points of contact between it and the other magnetic particles, as described herein. As a general rule, greater contact between the magnetic particle, the fluid medium and contact with other magnetic particles, corresponds to greater friction.

[0046] When referring to magnetic particles, as disclosed herein the “size” refers to at least one dimension of any of the components of the magnetic particles’ shape. This includes the size of the core or the shell, or both. For example, if the size of a spherical magnetic particle is disclosed as being 1mm this refers to the diameter of the core being 1mm or the shell being 1 mm, or both being 1mm. Thus, for a cylindrical core, the size refers to any of the dimensions e.g., the diameter of the cross-section or the cylinder length, or both.

[0047] In one embodiment the size of a magnetic particle ranges from between 0.01 to 5 mm. In one embodiment the size of a magnetic particle ranges from between 0.01 to 0.5 mm. In one embodiment the size of a magnetic particle ranges from between 0.5 to 1 mm. In one embodiment the size of a magnetic particle ranges from between 1 to 2 mm. In one embodiment the size of a magnetic particle ranges from between 2 to 5 mm.

[0048] In embodiments described herein, a plurality of magnetic particles are configured to move through a medium. In some embodiments the medium is selected from: solid, liquid or gas. As such, the magnetic particles in the plurality of magnetic particles can be of a variety of sizes i.e., they are not necessarily all the same size. In one embodiment the magneticparticles in a magnetic fleet are all the same. In another embodiment at least one magnetic particles in a magnetic fleet is not the same as the others.

[0049] In various embodiments the magnetic particle is configured to carry an active substance. Figure 3 shows embodiments of magnetic particle / s which carry at least one active substance 300. In some embodiments the magnetic particle comprises an active substance 301. For the clarity of Figure 3, the magnetic particle is represented by the magnetic core 104 (although other components of the magnetic particle, as described herein, can be incorporated therein). The “active substance” generally refers to any material that carries out a particular action. This can include a substance used for the purposes of a particular chemical reaction, catalysis, or delivery of a substance. For example: the magnetic particle (or fleet) delivering a therapeutic substance to a particular location in an organism, or a magnetic particle (or fleet) delivering an emulsifier to an oil spill. Figure 3A shows a schematic of a magnetic particle (represented by simply a core magnet 104) attached to an active substance 301. The shell is not shown, for simplicity. Whereas Figure 3A shows the active substance 301 disposed on one side of the magnetic core 104, Figure 3B shows the active substance 301 encapsulating the magnetic particle. In some embodiments the active substance is disposed on or in at least one magnetic particle within a plurality of magnetic particles i.e., within the fleet. In some embodiments at least one magnetic particle in the plurality of magnetic particles comprises at least one active substance. In some embodiments the active substance is in solid, liquid or gas form, or a combination thereof.

[0050] In some embodiments the active substance comprises at least one therapeutic compound. In some embodiments the therapeutic compound is selected from: analgesic, antibiotic, antiviral, antifungals, antidepressant, anti-inflammatory, antioxidant, anticoagulant, antihistamines, antihypertensives, anticonvulsants, antibodies, antidiabetics, antipsychotics, antacids, cancer drugs, corticosteroids, diuretics, nonsteroidal antiinflammatory drugs (NSAIDs), intravenous fluids, saline solution, dextrose solution, Ringer’s lactate solution, plasma-lyte, buffer, electrolytes, proton pump inhibitors, relaxants, sedatives, statins, steroids and vitamin supplements or any combination thereof.

[0051] In some embodiments the active substance is selected from: acid, alkali, emulsifier, solvent, surfactant, oxidizing agent, reducing agent, preservative, chelating agents, anticoagulant, enhancers, colorants, sweeteners, thickening agent, stabilizers, water, saline, bleaching agent and disinfectant or any combination thereof.

[0052] In some embodiments the magnetic particle comprising an active substance 300 further comprises a membrane 302. The membrane encapsulates the magnetic particlecomprising an active substance 300. As such, any number of magnetic particles comprising an active substance 300 can be comprised within the membrane 302. Figure 3D shows a magnetic particle comprising an active substance 300 with a membrane 302 and wherein the active substance is also comprised within the volume between the magnetic particle comprising an active substance 300 and the membrane 302 itself. Figures 3E and 3F show more than one magnetic particle comprising an active substance 300 as a fleet 310 comprised within a membrane 302. Figure 3E does not comprise additional active substance in between the magnetic particles whereas Figure 3F shows additional active substance comprised within the space between magnetic particles as encapsulated by a membrane. Any number of magnetic particle comprising an active substance 300 can be placed within such a membrane. Furthermore, any number of magnetic particles can be comprised within the membrane i.e., even magnetic particles that don’t comprise an active substance. It is noted that, by use of an external magnetic field the position of magnetic particles can change and remain comprised within the membrane. In some embodiments the membrane is flexible, dissolvable, porous or a combination of both.100053] Figure 5 shows some examples of 3D schematic illustrations of various embodiments of the magnetic particle 100 shell. For clarity, Figure 5 does not show the magnetic cores themselves, but rather the cavity within which the core is disposed. As such, when referring to a core comprising magnetic material, the term “magnetic core” or simply “core” is used. Typically, the shape of the core cavity is the same as the core magnet that is disposed therein. As used herein the “core cavity” is the cavity comprised within the shell within which the core magnet is disposed. However, in some embodiments, the core cavity is different in shape from the core magnet. In some embodiments the core cavity shape is selected from: random shape, spheroid, cylinder, tetrahedron, cube, octahedron, dodecahedron, icosahedron, cone, pyramid and rod or any combinations thereof. In various embodiments the magnetic particles 100 are an assembly of two halves of a shell: an upper shell 103a and a lower shell 103b. When the two shell halves 103a, 103b are brought together they leave a core cavity; the core, comprising magnetic material, being disposed therein (not shown in Figure 5). The core cavity is comprised of an upper core cavity 106a and a lower core cavity 106b. In some embodiments the core magnet (not shown) is immobilized within the core cavity 106a, 106b. In some embodiments the core cavity 106a, 106b is off-center. Forming the magnetic particles by assembling the upper shell 103a and lower shell 103b is not a limiting means by which the magnetic core comes to be disposed within the shell structure, as will become apparent. For example, in some embodiments the shell is formed inone step, forming one encapsulation material, not by the assembly of two shell halves. Figure 5A shows a cylindrical core and spherical shell. Figure 5B shows a larger cylindrical core than the one shown in Figure 5A and a spherical shell. Figure 5C shows a cuboidal core and spherical shell. Figure 5D shows a spherical core and spherical shell.

[0054] In one embodiment, to ensure that a magnetic core 104 is secured within the core cavity 106a, 106b, an additional adhesive is used to at least partially fill the core cavity.

[0055] The degree to which the magnetic core needs to move within the core cavity will vary between applications. Thus, the volume which the magnetic core occupies within the core cavity may vary. In some embodiments the magnetic core comprises between 1-100% of the volume of the core cavity. In some embodiments the magnetic core comprises 100% of the volume of the core cavity. In some embodiments the magnetic core comprises 95-100% of the volume of the core cavity. In some embodiments the magnetic core comprises 80-100% of the volume of the core cavity. In some embodiments the magnetic core comprises 50-100% of the volume of the core cavity. In some embodiments the magnetic core comprises 50-90% of the volume of the core cavity. In some embodiments the magnetic core comprises 10-50% of the volume of the core cavity. In some embodiments the magnetic core comprises 1-10% of the volume of the core cavity. Where more than one core is present in the magnetic particle, these percentages equally apply. For example: In some embodiments the at least one core comprises between 1-100% of the volume of the core cavity. In some embodiments the magnetic core comprises the entirety of the core cavity. Furthermore, to secure the magnet in place within the core cavity, either an additional adhesive is used, or the shell material is molded onto the core magnet to provide a tight seal around the core magnet.Magnetic Fleets of the Invention

[0056] In some embodiments the invention provides a magnetic fleet comprising a plurality of magnetic particles. These fleets are generally deployed to pass through media such as fluids. The versatility of magnetic fleets allows them to perform many tasks by means of an external magnetic field, as will become apparent herein.

[0057] In some embodiments the magnetic fleet comprises: a plurality of magnetic particles wherein each magnetic particle comprises at least one core and a shell; wherein each magnetic particle is in contact with at least one other magnetic particle in the plurality of magnetic particles;wherein the position of at least one magnetic particle within the plurality of magnetic particles is configured to change in response to an external magnetic field; and wherein the plurality of magnetic particles at least partially retain their configuration after the external magnetic field has been removed.

[0058] In some embodiments the magnetic fleet comprises between 2 and 1,000,000,000 magnetic particles. In some embodiments the magnetic fleet comprises between 2 and 1 ,000,000 magnetic particles. In some embodiments the magnetic fleet comprises between 2 and 1000 magnetic particles. In some embodiments the magnetic fleet comprises between 2 and 500 magnetic particles. In some embodiments the magnetic fleet comprises between 2 and 50 magnetic particles. In some embodiments the magnetic fleet comprises between 2 and 20 magnetic particles. In some embodiments the magnetic fleet comprises between 2 and 10 magnetic particles. In some embodiments the magnetic fleet comprises between 2 and 5 magnetic particles.

[0059] As described herein, to enable the appropriate response of magnetic particles and their motion, individually and as part of a fleet, the center of the core is not positioned at the center of the magnetic particles, in some embodiments. This is generally referred to as “off- center” or “asymmetric”. In some embodiments the magnetic core is positioned at the center of the magnetic particle. In some embodiments the magnetic particles further comprise a cavity disposed inside the magnetic particle wherein the magnetic core is comprised therein. As such, and in some embodiments, there is a gap between the core and the shell such that the core is not in full contact with the shell. In some embodiments the center of the core or the cavity, or a combination thereof, is not positioned at the center of the magnetic particle. Different magnetic particles within the fleet can have different configurations. For example, 50% of the magnetic particles in the fleet have off-center cores, and 50% of the magnetic particles in the fleet have centered cores. When the core cavity is larger than the magnetic core, it provides a degree of mobility for the core within the cavity. In some embodiments the core is configured to change position inside the magnetic particle. Whereas a spherical core can rotate 360 degrees within a spherical cavity (see Figure 2E), a rectangular-prism-shaped core has limited degrees of freedom within a rectangular cavity (Figure 2F).

[0060] An example of a therapeutic use of a magnetic fleet is provided. A fleet of magnetic particles comprising an active substance 300 can be comprised within a membrane (e.g., which is porous for delayed or slow release, or dissolvable), delivering a therapeutic substance to a particular location within an organism. As the fleet makes its way through the organism(e.g., through blood vessels, lumen, in between folds of the brain, the bronchi, etc.), after a particular amount of time the membrane will dissolve, releasing the active substance at a target location. In some embodiments the membrane is porous, and once the fleet of magnetic particles comprising an active substance 300 arrive at the target location, it is maintained in that position, slowly releasing the active substance over time. The rate of release of the active substance is optimized for a particular environment and situation. For example, an active substance may require a slow release, and thus the pore size comprised within the porous membrane will be selected accordingly. Furthermore, depending on the concentration differences between various substances, the rate of active substance transfer can be optimized. Once the active substance is delivered, the magnetic fleet, with or without the membrane, can be retrieved using the external magnet and returned to the entry point through which it was initially inserted. Or otherwise, it can exit through a different point.

[0061] As a result of different combinations of core, shell and cavity shapes, and their relative sizes, the magnet core may have a particular predisposition towards particular conformations within the cavity. Such states may be said to be “degenerate” where only a small number of conformations are ‘allowed’ by the geometry of the system. This is akin to a steric hindrance. For example, a magnetic core and cavity, with an identical pyramidal shape (with the apex pointing in the same direction), will always be configured in about the same direction if the pyramidal magnetic core fills enough space within the cavity. However, once such a magnetic core shrinks in size, the magnetic core’s rest state has the lowest rest energy when the core’s apex is aligned with the apex of the pyramid, whereas it will have other less- stable states when pointing in the direction of the other corners of the pyramidal cavity. Thus, there will be one favorable, low energy, state (i.e., apex aligned with apex) and four other states where the core’s apex aligns with the other vertices in the pyramid. As demonstrated, different combinations of core, shell and cavity shapes, and their relative sizes will generate different numbers of degenerate states. Thus, the configuration of these aspects is selected such that the core can change position within the magnetic particle i.e., within the cavity of the magnetic particle. This configuration can arise from the core being ‘loose’ inside the cavity, in some embodiments. The shape of the core and the cavity can dictate the degrees of freedom of the core to change position within the cavity. The term “change position” can signify a change in location within the coordinate space of the cavity, or a rotation of the core within the cavity, or both.

[0062] A magnetic fleet 600 comprising a plurality of magnetic particles 602 is shown passing through a narrow channel 601 by means of an external magnet 902 in Figure 6. Theexternal magnetic field is sometimes referred to, and understood as, any type of magnet (e.g., permanent or electromagnet), or a plurality of magnets, or a plurality of magnetic field sources. The depiction of the external magnet 902 of Figure 6 is not limited to a permanent magnet, but is shown in this manner for clarity. The magnetic particles 602 in Figure 6 are represented as circles, without reference to other components which can be incorporated therein (e.g., core, shell, cavity, additional layers, adhesive layer, etc.). Before a magnetic field is applied (not shown), the magnetic fleet 600 is in a rest-state conformation. In this case the magnetic fleet 600 forms a triangle, or arrowhead. The “rest-state” of a magnetic fleet refers to the magnetic particle 602 configuration within the fleet 600 without an external field applied. This partly depends on the space that the magnetic fleet 600 occupies. As the (arrowhead- shaped) magnetic fleet 600 approaches a narrow channel 601 the position of the magnetic particles 602 rearrange themselves in a chain in order to pass through the narrow channel 601. The magnetic coupling between the magnetic particles themselves is weak enough (due to the composition, shape and conformation of the shell, core, cavity, etc.) such that individual magnetic particles 602 change position relative to one another, but also remain in contact, at least partially. If the magnetic coupling is too strong, then the magnetic particles would not change position in the magnetic fleet 600 and would not pass through the narrow channel 601. If the magnetic coupling between magnetic particles 602 was too weak then the magnetic particles would disperse and not form part of a fleet or become disjointed. Recovery of such particles, after a task has been carried out, would be very challenging, if the magnetic field strength was too weak; potentially causing the loss of magnetic particles. For example: if such a magnetic fleet was deployed in the human brain, and the magnetic coupling was too weak, some magnetic particles would potentially not be retrieved if there is enough magnetic shielding, or the depth of travel was such that the external magnetic field is ineffective. The present invention finds the balance between strong and weak coupling, to enable the magnetic fleet to maintain inter-particle contact, but also to allow for the fleet configuration to change in response to external stimuli i.e., a magnetic field. Once the external magnet (not shown) channels the magnetic fleet 600 through the narrow channel 601, it exits the narrow channel and regains its prior configuration i.e., the rest-state. In some embodiments, the magnetic fleet maintains is chain shape when it exits the narrow channel. Examples of narrow channels of a biological nature include, but are not limited to: blood vessels, lumen, passage in between folds of the brain, the bronchi, etc. As stated elsewhere, each magnetic particle can carry a payload of an active substance to be delivered to a particular location via an external magnetic field. For example, an active-substance-carrying magnetic fleet 600 can pass through folds inthe brain to reach a specified location to release the active substance. Once the active substance has been released, the magnetic fleet 600 can be recovered by directing it to an exit point via an external magnetic field source 902. In some embodiments the external magnet 902 is located outside an organism comprising the magnetic fleet 600. In some embodiments the external magnet 902 is located at least partially inside the organism comprising the magnetic fleet 600. In other embodiments some magnets are placed external to the organism whereas other magnets are at least partially placed internally.

[0063] Figure 7 shows a similar configuration to Figure 6 but wherein the magnetic fleet 600 additionally comprises a membrane 302, providing a membrane-encapsulated magnetic fleet 700. Since the membrane 302 is flexible, it can change shape according to its environment e.g., when it passes through, or past, objects. In some embodiments the membrane is rigid; taking on the form of a platonic solid. The membrane-encapsulated magnetic fleet 700 is directed through the narrow channel 601 by means of an external magnetic 902. In such a scenario, the membrane-encapsulated magnetic fleet 700 may deliver a payload once the membrane dissolves, releasing an active substance in a target area. The magnetic fleet 600 is then retrieved by an external magnetic field.

[0064] As shown, and in some embodiments, when the membrane-encapsulated magnetic fleet 700 passes through a narrow channel 601, the magnetic fleet forms a chain of magnetic particles and the membrane 302 becomes elongated. Once the membrane-encapsulated magnetic fleet 700 exits the narrow channel 601, it returns to its rest state. Otherwise, the magnetic fleet maintains its chain formation. It is noted that the encapsulation membrane can be elastic, which will affect the configuration of the magnetic fleet.

[0065] The magnetic fleet can take on many formations. For the purposes of clarity, the terms “formation”, “conformation” and “position” are used interchangeably when referring to the general structure and / or position of magnetic particles within a fleet of particles. For example, a magnetic fleet that takes on the formation of a pyramid is described as taking on a pyramidal formation (or ‘conformation’, etc.). Figure 8 shows a number of formations that a magnetic fleet can take on either in its rest-state (i.e., with no external magnetic field) or in an active-state (i.e., when an external magnetic field acts on the magnetic fleet). In some embodiments the plurality of magnetic particles in the magnetic fleet are configured together in any of the following formations selected from: a chain, a ring, an arrow, single layer, multilayers and a cluster or any combination thereof. A cluster being an ordered or disordered collection of magnetic particles. Figure 8E shows one embodiment where a plurality of magnetic particles is comprised of different shapes. For example, if two separate pluralities ofmagnetic particles (comprised of different shapes) are brought together, they may form the magnetic field shown in Figure 8E. A magnetic fleet comprising magnetic particles of different shapes may be done at the outside, or as a result of joining two magnetic fleets together. For example, if one fleet has become unmovable in a particular location (e.g., a fold in the brain), another magnetic fleet can be delivered into the organism to retrieve the first magnetic fleet by its increased magnetic interaction.

[0066] Figure 9 shows the packing of a fleet of hexagonal magnetic particles 100 (with rectangular magnets as the core 104). Although magnetic particles are 3-dimensional, the schematic illustration shows them in 2-dimensions for the purposes of examples alone. As can be seen, due to the shape of the shell 103, magnetic particles 100 stack in a tight and orderly manner, forming a tiling. In some embodiments the rest-state of a magnetic fleet is ordered, such as that shown in Figure 9. Otherwise, and in some embodiments, the rest-state of a magnetic disordered.

[0067] Magnetic particles can comprise more than one magnetic core. In some embodiments, the magnetic particle comprises two magnetic cores. In some embodiments the two (or more) magnetic cores are identical. In some embodiments the two (or more) magnetic cores are different. By ‘the same’ and ‘different’ it is intended that the material composition and / or shape are considered. Figure 10A illustrates a basic scheme for a magnetic particle 100 with two magnetic cores 104a, 104b. The two magnetic cores 104a, 104b are connected by an attaching element 107. The attaching element 107 can be in a similar form to the ‘shell’ as described herein. Figure 10B shows two spheroidal magnetic cores 104 that are located at either end of an attaching element 107 in the form of an elongated ellipsoidal shell 106. The poles of the two magnetic cores 104a, 104b are positioned in the same direction. However, in some embodiments the poles of one of the two magnetic cores 104a, 104b is reversed such that the two south poles (or the two north poles) face each other. For the purposes of clarity, core cavities are not shown in Figure 10. A magnetic fleet 600 comprising a plurality of such elongated magnetic particles 100 is shown in Figure 10C. In this case the magnetic fleet 600 is shown in the formation of a ring.Magnetic Fleet Systems of the Invention

[0068] Manipulating the magnetic fleet by means of a plurality of magnetic field is crucial in directing the motion, position, conformation, configuration, relative-position, speed, rotation and shape of the magnetic fleet, including one that is encapsulated in a membrane.

[0069] In some embodiments the invention is directed towards a magnetic fleet system comprising: the magnetic fleet as disclosed herein; and at least one external magnetic field.

[0070] In general, the at least one external magnetic field, refers to either a permanent magnet or an electromagnet or a combination thereof. The terms “external magnetic field” and “external magnet” are understood interchangeably, in various embodiments. As such, to direct a magnetic fleet a plurality of external magnetic fields can be used to direct the magnetic field on a path.

[0071] In one embodiment a plurality of external magnetic fields are configured to manipulate the motion of magnetic particles to a location with a resolution of about 0.1mm. In one embodiment a plurality of external magnetic fields are configured to manipulate the motion of magnetic particles to a location resolution of about 1 mm. In some embodiments the external magnetic field is placed outside the environment of the magnetic fleet. In other embodiments the external magnetic field is placed at least partially within the environment of the magnetic fleet. For example: in directing a magnetic fleet through the brain (e.g., frontal lobes, parietal lobes, occipital lobes, temporal lobes, cerebellum, etc.) the external magnetic field may be placed inside a patient’s mouth or nasal cavity to increase the magnetic coupling between the magnetic fleet and the external magnetic field.Methods of Operating a Magnetic Fleet

[0072] Magnetic fleets can be manipulated for a variety of applications, some of which will be outlined herein. Magnetic fleets can be used for therapeutic and medical applications. For example, magnetic fleets can carry a payload to a target location within an organism. In some embodiments the organism is selected from: human or non-human. This payload can be a therapeutic agent or active substance. Magnetic fleets can be used in dermatology. For example, for massaging, rubbing, or scrubbing various parts of the body. In this case a magnetic fleet can be deployed in the mouth and, with the use of an external magnetic field, can be used to contour around plaque for cleaning purposes. Topical and uniform application of a liquid, ointment, cream on a surface, can be carried out by means of a magnetic fleet.

[0073] In some embodiments magnetic fleets can be maneuvered through any of the following selected from: brain, lungs, blood vessels, stomach, intestines, reproductive organs, urinary system and esophagus. For example, penetration of the occipital cyst in the brain, via folds in the brain, can be carried out with a magnetic fleet.

[0074] Additionally, a magnetic fleet can be used to widen a channel as they pass through it. For example, spreading apart the folds of tissue (e.g., the brain) to allow other items (e,g., parts of the magnetic fleet, or bodily fluids) to pass through; or to widen valves in blood vessels. Magnetic fleets can also be used to break through blockages in vessels in the body. For example, through lumen, blood vessels, etc. Other examples include using magnetic fleets to release blockages in the urinary system, blood system, cardiovascular system, reproductive system, etc. Magnetic fleets can be used to deliver a nanobot or a camera to a target location for diagnostics. Another example: regarding cystic fibrosis, mucus producing cells malfunction, producing abnormally thick or sticky mucus which can negatively affect organs; magnetic fleets can be used to deliver drugs to treat these symptoms or be used to agitate the mucus by vibrating the magnetic fleet. In some embodiments, fast agitation of the magnetic fleet generates heat. Such heat can be used to reduce the viscosity of a liquid within which it is agitated.

[0075] In some embodiments the magnetic fleet is configured to move material in the body. In some embodiments the magnetic fleet is configured to relocate material in the body. In some embodiments the magnetic fleet is configured to encapsulate material in the body. For example, moving hemorrhagic material related to strokes. In another example, occlusive and spillage material can be encapsulated and moved. In some embodiments magnetic fleets comprise absorptive material. For example: a sponge, or sponge-like material. In this manner a magnetic fleet can collect material at particular locations in the body. Such material can be solid, liquid, or gas or a combination thereof.

[0076] The magnetic particles within the fleet can be provided with a rough surface. Such a surface can be used to make high resolution incisions inside a body as an assistance tool to surgeons. Thus, magnetic fleets can be used in micro-surgery and as an aid to keyhole surgery.

[0077] The present invention provides methods of operating a magnetic fleet system. The magnetic fleet system comprises a magnetic fleet and at least one external magnetic field. In some embodiments the magnetic fleet system comprises at least one magnetic fleet and at least one external magnetic field. Thus, multiple fleets can be used together, as will be described herein.

[0078] In some embodiments the method of operating a magnetic field comprises: a. providing a magnetic fleet system; b. injecting the magnetic fleet at an entry point of an environment;c. operating the at least one external magnetic field to manipulate the location, orientation and configuration of the magnetic fleet to a target location within the environment; d. carrying out an action at the target location; e. optionally carrying out steps ‘c’ and ‘d’ at least one more time; and f. retrieving the magnetic fleet by operating the at least one external magnetic field via an exit point

[0079] The magnetic field is configured to manipulate the location, orientation and configuration of individual magnetic particles and the magnetic fleet as a whole. The external magnetic field, depending on its relative position, will affect each individual magnetic particle, and the fleet as a whole, differently. The “location” refers to the position of magnetic particles and / or the fleet within an environment. The “orientation” refers to relative positions, in particular the angle at which a magnetic particle is tilted. The “configuration” refers to the arrangement of magnetic particles within a magnetic fleet.

[0080] In some embodiments the environment is a medium that comprises a liquid. In some embodiments the environment is selected from: a living organism and a body of liquid. In some embodiments the entry point is the same as the exit point. In other embodiments the entry and exit points are different. In some embodiments the action is selected from delivering an active substance, releasing an active substance, making an incision, widening a channel, unblocking a channel, blocking a channel, massaging, scrubbing, polishing and cleaning. In some embodiments the target location is selected from: brain, lungs, blood vessels, stomach, intestines, reproductive organs, urinary system and esophagus.Magnetic Layers of the Invention

[0081] Magnetic fleets can be placed in between two confining planes, forming layers (or ‘sheets’) of magnetic particles. Thus, flatting a magnetic fleet provides a magnetic layer, or multi-layer. Magnetic fleets in the form of a layer (or multilayers) of magnetic particles are referred to herein as “magnetic layers”. Such layers can be organized with high uniformity or otherwise with little uniformity. Magnetic layers can be used to change the way a particular surface looks, e.g., its color. When magnetic particles are colored on their surface, and an external magnetic field alters their position (e.g., by rotation), the surface of the layer will change in appearance. This can be used for camouflage applications. For example, magnetic particles that have two (or more) colors painted on their surfaces, and are confined within an upper / lower plane. A magnetic field can be used to change the color that the layer looks e.g.,from green to yellow. For example: the north pole is painted green, and the south pole is painted yellow. Other embodiments include modifying the surface of the magnetic particles in the layer to have different responses to light, such as reflectivity / absorption or dispersion.

[0082] In some embodiments the invention provides a magnetic layer comprising: the magnetic fleet as described herein; an upper plane and a lower plane configured to hold the plurality of magnetic particles therebetween.

[0083] In some embodiments the magnetic layer comprises: a plurality of magnetic particles wherein each magnetic particle comprises at least one core and a shell; an upper plane and a lower plane configured to hold the plurality of magnetic particles therebetween, wherein the position of at least one magnetic particle within the plurality of magnetic particles is configured to change in response to an external magnetic field; and wherein the plurality of magnetic particles at least partially retain their configuration after the external magnetic field has been removed.

[0084] The number of magnetic particles used in such a layer is any amount that can fill the space in between the upper and lower plane with a desired density. For example, where the upper and lower plane each comprise a Ixlm sheet and where the desirable outcome of the density of magnetic particles (with a diameter of 1mm) fills 90% of the space, in a single layer, between the upper and lower plane, the number of magnetic particles is approximately 900,000 magnetic particles, depending on how the magnetic particles pack.

[0085] Figure 11A shows the cross-section of a magnetic layer 110 which comprises a magnetic fleet 600 suspended in between an upper plane 901 and a lower plane 900. The magnetic particles 100 are shown in a starting position with all of their magnetic poles aligning identically in the vertical axis. Figure 11B shows an additional external magnet 902 which is passed along the lower plane 900. The two left magnetic particles 100 are shown to have flipped polarity when in close proximity to the external magnet 902. As the external magnet 902 moves laterally across the underside of the lower plane 900, the individual magnetic particles 100 in the magnetic layer 110 flip polarity. Figure 11C shows the final configuration of the magnetic particles 100 in the magnetic layer 110 wherein the poles of the magnetic particles 100 in the magnetic layer 110 have all flipped from their original configuration, shown in Figure 11A. In various embodiments, once the external magnet 902 is removed the magnetic particles 100 maintain their configuration.

[0086] In one embodiment the poles of magnetic particles are visibly distinguishable. For example, the north pole is colored white, and the south pole is colored black. Thus, the magnetic particles can be coated with additional materials such as paints, inks, lubricants, electroactive materials, according to the requirements of the user, to change the appearance or surface properties of the magnetic layer.

[0087] Figure 12 shows magnetic layers with different sizes of magnetic particles suspended between an upper and lower plane. Figure 12A shows magnetic particles 100 (core, cavity, shell not shown for simplicity) suspended in between an upper plane 901 and a lower plane 900. In some embodiments the magnetic particles 100 in the magnetic layer 110 form a continuous contact throughout the magnetic layer. In other embodiments, not all the magnetic particles 100 are in contact throughout the magnetic layer 110. Figure 12B shows smaller magnetic particles 100 than in Figure 12A and thus multiple magnetic particles (and layers) can align across the gap between the upper plane 901 and the lower plane 900. In Figure 12B some of the magnetic particles, or groups / clusters of magnetic particles are disconnected from other groups / clusters. Figures 12C and 12D show approximate 3D representations of Figures 12A and 12B, respectively.

[0088] In some embodiments the upper plane, the lower plane, or a combination thereof comprises a polymer. In some embodiments the polymer is selected from: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), nylon, polycarbonate (PC), acrylonitrile-butadiene- styrene (ABS), polyurethane (PU), polyvinylidene fluoride (PVDF), perfluoroethylene (PFE), polymethyl methacrylate (PMMA), polyimide (PI), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyetheretherketone (PEEK) and silicone or any combinations thereof.

[0089] In some embodiments the magnetic layer further comprises a fluid medium disposed between said upper plane and said lower plane. In some embodiments the fluid medium is transparent. In some embodiments the fluid medium is selected from: water, glycerol, glycol, gel, oil and lubricant or any combination thereof. The viscosity of the medium is selected according to the application required. In general, the viscosity is selected such that the magnetic particles remain in place in a rest-state, or after a magnetic field has been removed.

[0090] In some embodiments the magnetic layer further comprises a plurality of spacers disposed between the upper plane and the lower plane. These spacers can take on any form or shape, to separate the planes at approximately a constant separation. In some embodimentsthe gap between the upper and lower plane ranges between 0.5 and 50mm. In some embodiments the gap between the upper and lower plane ranges between 0.5 and 10mm. In some embodiments the gap between the upper and lower plane ranges between 0.5 and 5mm.Magnetic Layer System of the Invention

[0091] The magnetic layer of the invention can be coupled with at least one external magnetic field source and / or a plurality of external magnetic fields. As such, the configuration of the magnetic particles within the magnetic layer can change. Once the magnetic field is removed, the magnetic particles remain in place i.e., they maintain their configuration over at least a short period of time. In some embodiments, the configuration of the magnetic particles in the magnetic layer are maintained indefinitely i.e., until a further external force is acted upon the magnetic layer system.

[0092] In some embodiments the magnetic layer system comprises: the magnetic layer disclosed in various embodiments herein; and at least one external magnetic field.100093 ] Since the magnetic layer is comprised within an upper and lower plane, a plurality of external magnetic fields can be readily coupled to one side of the magnetic layer system. In one embodiment the at least one external magnetic field is a plurality of electromagnets operating as pixels, to affect changes in the configuration of magnetic particles within the magnetic layer. This, in turn, facilitates the ‘drawing’ of patterns within the magnetic layer.

[0094] Embodiments of a method of operating the magnetic layer system comprise, providing a magnetic layer and operating the at least one external magnetic field to manipulate the location, orientation and configuration of the magnetic particles in the magnetic layer.Method of Fabricating Magnetic Particles, Fleets and Layers100095 ] The magnetic particles comprise a core and a shell or a core with an encapsulation material disposed thereon. The holding structure for the magnetic layer comprises an upper plane and a lower plane. The holding structure may additionally comprise spacers.

[0096] The following non-limiting list of processes are incorporated into the method of fabricating the shell: imprinting, rolling, dripping, cutting, molding, and etching said shell to comprise said core cavity or any combinations thereof. In some embodiments the mold comprises a shape corresponding to any of the shapes disclosed herein. Shell structures can be made in their entirety in a single step with one structure, or as an assembly of more thanone structure e.g., two half shells or multiple shell sections being assembled together. For example, two half-shell structures incorporating a core cavity can be assembled together forming the full-shell structure. The multiple shell structures can be assembled by: adhesive material, glue, pinned, welded, pressed, heat-pressed and, held together by further encapsulation material.

[0097] In some embodiments the core cavity can be further fabricated by any of the following processes selected from: drilling, 3D printing, molding, melting, solidifying, imprinting and etching or any combinations thereof. Tn some embodiments the molds are configured to provide sections of the shell structure such that components of the shell can be assembled together.

[0098] Magnetic materials, such as magnetic or ferromagnetic, used in magnetic cores can be manufactured by standard means. Methods to manufacture small magnetic cores can comprise any of the following processes selected from: grinding, milling, mixing and melting, pressing, sintering, and machining or any combinations thereof. For example, typical neodymium magnets comprise neodymium, iron and boron in a pure form. These components are then mixed and melted in a furnace. The mixture is heated above the melting point and the raw materials form a metal alloy. Once the alloy has been created it is cooled and crushed into a fine powder in a milling machine. The magnetic powder is then pressed into a mold using a hydraulic press, in some embodiments. In some embodiments the mold comprises a shape corresponding to any of the shapes disclosed herein. The mold is designed to form the magnet into any of the shapes and sizes disclosed herein. The pressed magnet is then sintered, causing the magnetic fragments to fuse to form a solid magnet. Finally, the magnet is machined to the desired dimensions and shape.

[0099] In some embodiments, magnetic cores are inserted into manufactured cavities within the shells. The core and shell can be held together by adhesives, pins or other forms of restraining means.[000100] In some embodiments the shell is formed around the core. In other embodiments the core is inserted into a cavity-comprising shell.[000101] In one embodiment, the term “a” or “one” or “an” refers to at least one. In one embodiment the phrase “two or more” may be of any denomination, which will suit a particular purpose. In one embodiment, “about” or "approximately" may comprise a deviance from the indicated term of + 1 %, or in some embodiments, - 1 %, or in some embodiments, + 2.5 %, or in some embodiments, ± 5 %, or in some embodiments, ± 7.5 %, or in someembodiments, ± 10 %, or in some embodiments, ± 15 %, or in some embodiments, ± 20 %, or in some embodiments, ± 25 %.[000102] Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations, and modifications can be made without departing from the scope of the presently disclosed subject matter, mutatis mutandis.

Claims

CLAIMS1. A magnetic fleet comprising: a plurality of magnetic particles wherein each magnetic particle comprises at least one core and a shell; wherein each magnetic particle is in contact with at least one other magnetic particle in said plurality of magnetic particles; wherein the position of at least one magnetic particle within said plurality of magnetic particles is configured to change in response to an external magnetic field; and wherein said plurality of magnetic particles at least partially retain their configuration after said external magnetic field has been removed.

2. The magnetic fleet of claim 1 wherein said plurality of magnetic particles comprises between 2 and 1,000,000,000 magnetic particles.

3. The magnetic fleet of claim 3 further comprising a cavity disposed inside said magnetic particle wherein said magnetic core is comprised therein.

4. The magnetic fleet of claim 1 wherein the center of said core or said cavity, or a combination thereof, is not positioned at the center of said magnetic particle.

5. The magnetic fleet of claim 3 wherein said core is configured to change position inside said magnetic particle.

6. The magnetic fleet of claim 3, wherein the shape of said at least one core, said shell has a shape, said cavity, or any combination thereof, is selected from a list comprising: random shape, spheroid, cylinder, tetrahedron, cube, octahedron, dodecahedron, icosahedron, cone, pyramid and rod or any combinations thereof.

7. The magnetic fleet of claim 1, wherein said at least one core comprises between 1 to 99% of the volume of said magnetic particle.

8. The magnetic fleet of claim 1, wherein said at least one core comprises a magnetic material.

9. The magnetic fleet of claim 8, wherein said magnetic material comprises: permanent magnet, ferromagnet, iron, aluminum, cobalt, nickel, gadolinium, dysprosium, neodymium, samarium, terbium, molybdenum, copper, europium, holmium, ceramic magnet and alnico magnet or any combinations thereof.

10. The magnetic fleet of claim 9, wherein said ceramic magnet comprises: strontium ferrite, barium ferrite, titanium ferrite, yttrium ferrite, yttrium iron garnet and lithium ferrite or any combination thereof.

11. The magnetic fleet of claim 1 , wherein said shell comprises a polymer.

12. The magnetic fleet of claim 11 wherein said polymer is selected from: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), nylon, polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polyurethane (PU), polyvinylidene fluoride (PVDF), perfluoroethylene (PFE), polymethyl methacrylate (PMMA), polyimide (PI), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyetheretherketone (PEEK) and silicone or any combinations thereof.

13. The magnetic fleet of claim 1, wherein said shell comprises a metal.

14. The magnetic fleet of claim 13, wherein said metal is selected from: copper, titanium, tungsten, 416 stainless steel, nitinol, and an alloy or any combination thereof.

15. The magnetic fleet of claim 1, wherein the size of at least one dimension of said magnetic particles ranges from between 0.01 to 5 mm.

16. The magnetic fleet of claim 1, wherein said magnetic particles further comprise at least one coating disposed on said at least one core, said shell or a combination thereof.

17. The magnetic fleet of claim 1, wherein said plurality of magnetic particles are configured together in any of the following formations selected from: a chain, a ring, an arrow, single layer, multi-layers and a cluster or any combination thereof.

18. The magnetic fleet of claim 1 wherein at least one magnetic particle in said plurality of magnetic particles comprises at least one active substance.

19. The magnetic fleet of claim 1 further comprising an encapsulating membrane which encapsulates said plurality of magnetic particles.

20. The magnetic fleet of claim 19 wherein said membrane is flexible, dissolvable, porous or a combination thereof.

21. The magnetic fleet of claim 18 wherein said at least one active substance is additionally disposed between said magnetic particles and said membrane.

22. The magnetic fleet of claim 18 wherein said active substance is in solid or liquid form or a combination thereof.

23. The magnetic fleet of claim 18 wherein said active substance comprises at least one therapeutic compound.

24. The magnetic fleet of claim 23 wherein said at least one therapeutic compound is selected from: analgesic, antibiotic, antiviral, antifungals, antidepressant, antiinflammatory, antioxidant, anticoagulant, antihistamines, antihypertensives, anticonvulsants, antibodies, antidiabetics, antipsychotics, antacids, cancer drugs, corticosteroids, diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs), intravenous fluids, saline solution, dextrose solution, Ringer’s lactate solution, plasma-lyte, buffer, electrolytes, proton pump inhibitors, relaxants, sedatives, statins, steroids and vitamin supplements or any combination thereof.

25. A magnetic fleet system comprising:The magnetic fleet of claim 1 ; and At least one external magnetic field.

26. A magnetic layer, comprising: a plurality of magnetic particles wherein each magnetic particle comprises at least one core and a shell; an upper plane and a lower plane configured to hold said plurality of magnetic particles therebetween, wherein the position of at least one magnetic particle within said plurality of magnetic particles is configured to change in response to an external magnetic field; andwherein said plurality of magnetic particles at least partially retain their configuration after said external magnetic field has been removed.

27. The magnetic layer of claim 26 further comprising a fluid medium disposed between said upper plane and said lower plane.

28. The magnetic layer of claim 27 wherein said fluid medium comprises any of the following selected from: water, glycerol, glycol, gel, oil and lubricant or any combination thereof.

29. The magnetic layer of claim 26 further comprising a plurality of spacers disposed in between said upper plane and said lower plane.

30. The magnetic layer of claim 26 wherein said upper plane, said lower plane, or a combination thereof comprise a polymer.

31. The magnetic layer of claim 30 wherein said polymer is selected from: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), nylon, polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polyurethane (PU), polyvinylidene fluoride (PVDF), perfluoroethylene (PFE), polymethyl methacrylate (PMMA), poly imide (PI), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyetheretherketone (PEEK) and silicone or any combinations thereof.

32. The magnetic layer of claim 26 wherein the gap between said upper plane and said lower plane ranges between 0.5 and 50mm.

33. A magnetic layer system comprising: the magnetic layer of claim 25; and at least one external magnetic field.

34. A method of operating a magnetic fleet system comprising: a. providing the magnetic fleet system of claim 33; b. injecting said magnetic fleet at an entry point of an environment; c. operating said at least one external magnetic field to manipulate the location, orientation and configuration of said magnetic fleet to a target location within said environment;d. carrying out an action at said target location; e. optionally carrying out steps ‘c’ and 'd' at least one more time; and f. retrieving said magnetic fleet by operating said at least one external magnetic field via an exit point.

35. The method of claim 34 wherein the environment is selected from: a living organism and a body of liquid.

36. The method of claim 34 wherein said entry point and said exit point are the same.

37. The method of claim 34 wherein said target location is selected from: brain, lungs, blood vessels, stomach, intestines, reproductive organs, urinary system and esophagus.

38. The method of claim 34 wherein said action comprises: delivering an active substance, releasing an active substance, making an incision, widening a channel, unblocking a channel, blocking a channel, massaging, scrubbing, polishing and cleaning.

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