U.S. patent application number 14/930126 was filed with the patent office on 2017-03-09 for method and apparatus for non-contact axial particle rotation and decoupled particle propulsion.
The applicant listed for this patent is WEINBERG MEDICAL PHYSICS LLC. Invention is credited to Lamar Odell MAIR, Aleksandar Nelson NACEV, Irving N. WEINBERG.
Application Number | 20170069416 14/930126 |
Document ID | / |
Family ID | 55853416 |
Filed Date | 2017-03-09 |
United States Patent
Application |
20170069416 |
Kind Code |
A9 |
MAIR; Lamar Odell ; et
al. |
March 9, 2017 |
METHOD AND APPARATUS FOR NON-CONTACT AXIAL PARTICLE ROTATION AND
DECOUPLED PARTICLE PROPULSION
Abstract
An apparatus and method for magnetic particle manipulation
enables the particle to be rotated and translated independently
using magnetic fields and field gradients, which produce the
desired decoupled translational and rotational motion. The
apparatus and the method for manipulation may be implemented in
parallel, involving many particles. The rotational magnetic field
used to induce rotational motion may be varied to induce particle
motion, which is either in phase or out of phase with the
rotational magnetic field. The magnetic fields and gradients
described herein may be generated with permanent magnets,
electromagnets, or some combination of permanent magnets and
electromagnets.
Inventors: |
MAIR; Lamar Odell;
(Washington, DC) ; NACEV; Aleksandar Nelson;
(Bethesda, MD) ; WEINBERG; Irving N.; (Bethesda,
MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WEINBERG MEDICAL PHYSICS LLC |
Bethesda |
MD |
US |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20160125994 A1 |
May 5, 2016 |
|
|
Family ID: |
55853416 |
Appl. No.: |
14/930126 |
Filed: |
November 2, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62073360 |
Oct 31, 2014 |
|
|
|
62182901 |
Jun 22, 2015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 1/406 20130101;
H01F 7/20 20130101; H02N 15/00 20130101; B82B 3/0066 20130101; H01F
1/00 20130101; H01F 7/0278 20130101; H01F 13/00 20130101 |
International
Class: |
H01F 13/00 20060101
H01F013/00; H01F 7/20 20060101 H01F007/20; H01F 7/02 20060101
H01F007/02 |
Claims
1. An apparatus for rotating and translating at least one particle,
the apparatus comprising: means for generating magnetic force and
torque; and at least one particle, wherein at least some portion of
the at least one particle contains a magnetizable material, wherein
the generated magnetic force is applied to at least some portion of
the at least one particle to cause translational motion of the
particle, wherein the generated magnetic torque is applied to at
least some other portion of the same at least one particle to cause
rotation of the particle, and wherein the ratio of the
translational and rotational velocities of the particle is
variable.
2. The apparatus of claim 1, wherein the particle is introduced in
a body, and a ratio of the translational and rotational velocities
of the particle is varied while the particle is in the body.
3. The apparatus of claim 1, wherein the means for generating
magnetic force includes means for generating a rotational field
ranging from 1 Hz to 1000 Hz.
4. The apparatus of claim 1, wherein the at least one particle is
composed of polymeric, metallic, insulating, semiconducting,
ceramic, or combinations of at least two of these materials.
5. The apparatus of claim 1, wherein the at least one particle
houses electronics, molecules/drugs, proteins, cells, or energy
scavenging components.
6. The apparatus of claim 1, wherein at least one of the rotation
of the at least one particle and the decoupled translational motion
of the at least one particle are implemented in conjunction with
the production and application of magnetic fields to apply
repulsive and/or propulsive forces so as to manipulate the at least
one particle.
7. The apparatus of claim 1, wherein manipulation of the at least
one particle is performed by setting up appropriate magnetic
gradient fields with or without pre-polarizing pulses.
8. The apparatus of claim 1, wherein the at least one particle is
one of a plurality of particles, wherein each particle of the
plurality of particles includes some portion or component that
contains a magnetizable material, wherein magnetic torque causing
rotation of each of the plurality of particle is decoupled from the
magnetic force causing translational motion.
9. The apparatus of claim 1, further comprising a solution that
contains a plurality of particles including the at least one
particle, wherein each particle of the plurality of particles
includes some portion or component that contains a magnetizable
material, wherein magnetic torque causing rotation of each of the
plurality of particle is decoupled from the magnetic force causing
translational motion.
10. The apparatus of claim 1, where an amplitude and frequency of a
magnetic field causing rotation of the at least one particle is
independent of an amplitude and frequency of a magnetic gradient
that is causing translation of the at least one particle.
11. A method for rotating and translating at least one particle,
the method comprising: generating and applying a magnetic force and
torque upon at least one particle, wherein the at least one
particle includes at least two segments, each of which contains a
magnetizable material; applying the magnetic force to at least one
segment in order to cause translational motion of the particle;
applying the magnetic torque to at least one other segment in order
to cause rotational motion of the particle, wherein a ratio of the
resultant translational and rotational velocities of the particle
is variable.
12. The method of claim 11, wherein the particle is introduced in a
body, and a ratio of the translational and rotational velocities of
the particle is varied while the particle is in the body.
13. The method of claim 11, wherein the generation of the magnetic
force generates a rotational field ranging from 1 Hz to 1000
Hz.
14. The method of claim 11, wherein the at least one particle is
composed of polymeric, metallic, insulating, semiconducting,
ceramic, or combinations of at least two of these materials.
15. The method of claim 11, wherein the at least one particle
houses electronics, molecules/drugs, proteins, cells, or energy
scavenging components.
16. The method of claim 11, wherein at least one of the rotation of
the at least one particle and the decoupled translational motion of
the at least one particle are implemented in conjunction with the
production and application of magnetic fields to apply repulsive
and/or propulsive forces so as to manipulate the at least one
particle.
17. The method of claim 11, wherein manipulation of the at least
one particle is performed by setting up appropriate magnetic
gradient fields with or without pre-polarizing pulses.
18. The method of claim 11, wherein the at least one particle is
one of a plurality of particles, wherein each particle of the
plurality of particles includes some portion or component that
contains a magnetizable material, wherein magnetic torque causing
rotation of each of the plurality of particle is decoupled from the
magnetic force causing translational motion.
19. The method of claim 11, wherein a solution that contains a
plurality of particles including the at least one particle, wherein
each particle of the plurality of particles includes some portion
or component that contains a magnetizable material, wherein
magnetic torque causing rotation of each of the plurality of
particle is decoupled from the magnetic force causing translational
motion.
20. The method of claim 11, wherein an amplitude and frequency of a
magnetic field causing rotation of the at least one particle is
independent of an amplitude and frequency of a magnetic gradient
that is causing translation of the at least one particle.
Description
CROSS REFERENCE
[0001] This application claims priority under 35 U.S.C. 119(e) to
U.S. Provisional Patent Application No. 62/073,360 (incorporated by
reference in its entirety) filed on Oct. 31, 2014, entitled "METHOD
AND APPARATUS FOR NON-CONTACT AXIAL PARTICLE ROTATION AND DECOUPLED
PARTICLE PROPULSION."
FIELD OF THE INVENTION
[0002] Disclosed embodiments are directed to a method and apparatus
of manipulating magnetic particles.
SUMMARY
[0003] Disclosed embodiments provide an apparatus and method for
magnetic particle manipulation that enables the particle to be
rotated and translated independently using generated magnetic
fields and field gradients, which produce the desired decoupled
translational and rotational motion.
[0004] Disclosed embodiments enable such manipulation of a particle
with more than one magnetization direction.
[0005] Disclosed embodiments provide an apparatus and method for
manipulation that may be implemented in parallel, involving many
particles.
[0006] Disclosed embodiments provide an apparatus and method for
manipulating at least one particle which combines a magnetic
gradient for translation of the particle with a magnetic field for
rotating at least one particle, the method being used to induce
simultaneous particle translation and rotation.
[0007] Disclosed embodiments provide and utilize a rotational
magnetic field to induce rotational motion, wherein the rotational
magnetic field may be varied to induce particle motion, which is
either in phase or out of phase with the rotational magnetic
field.
[0008] Disclosed embodiments provide and utilize magnetic fields
and gradients that may be generated with permanent magnets,
electromagnets, or some combination of permanent magnets and
electromagnets.
BRIEF DESCRIPTION OF THE FIGURES
[0009] The detailed description particularly refers to the
accompanying figures in which:
[0010] FIGS. 1-4 illustrate an embodiment wherein rotational
manipulation is achieved by application of a rotating field with
zero or negligible field gradient
(H.sub.rotating-zero-gradient).
[0011] FIGS. 5-6 illustrate an embodiment that may use a
superparamagnetic particle that may be partially coated with a
ferromagnetic component, the ferromagnetic component being
magnetized in a direction perpendicular to the long axis of the
particle.
[0012] FIGS. 7-8 illustrate how, once a magnetic field is removed,
magnetization of the superparamagnetic bulk of the particle
illustrated in FIGS. 5-6, undergoes Neelian relaxation (arising due
to changes of intrinsic magnetization within the nanoparticles) in
accordance with at least one disclosed embodiment.
[0013] FIGS. 9-14 illustrate a configuration provided in accordance
with the disclosed embodiments to provide a combination of rotation
and propulsion forces on a particle(s) in accordance with at least
one disclosed embodiment.
[0014] FIG. 15 illustrates a cylinder with a magnetic segment with
a length more than twice the cylinder diameter having a
magnetization axis along the length of the cylinder in accordance
with at least one disclosed embodiment.
[0015] FIG. 16 illustrates one example of operation of an apparatus
provided in accordance with the disclosed embodiments.
DETAILED DESCRIPTION
[0016] The frequent references to magnetic fields requires a brief
index of terms.
[0017] A magnetic field with negligible gradient may be referenced
as H.sub.zero-gradient. If this magnetic field is rotating, it may
be referenced as H.sub.rotating-zero-gradient. One example of a
rotating field with zero gradient is the field generated by an
alternating current carrying coil that is rotated on any axis that
is parallel to the face of the coil. By rotating an alternating
current carrying wire on an axis parallel to the face of the wire,
a zero-gradient magnetic field is generated at the center of the
coil.
[0018] A magnetic field gradient may be referenced as
H.sub.with-gradient. If this magnetic field gradient is rotating,
then it may be referenced as H.sub.rotating-with-gradient. A
rotating magnetic field with a gradient may be generated by
rotating an elongated bar magnet around its minor axis (that is,
rotating the bar magnet about its lengthwise midpoint).
[0019] A magnetic particle has an associated magnetic field,
similar to the magnetic field of a common bar magnet. The
particle's magnetic field may be referenced as H.sub.particle.
[0020] A magnetic particle also has a magnetization. The particle's
magnetization is the magnetic ordering of magnetic domains that
compose the particle. The particle's magnetization may be
referenced as M.sub.particle.
[0021] A magnetic particle may have two distinct magnetic segments,
with each section having its own magnetization direction. In the
case of multiple magnetizable segments on the same particle,
segment magnetizations may be referred to as M.sub.1,particle and
M.sub.2,particle. In the case of a cylindrical particle,
M.sub.1,particle will refer to magnetization along the long axis of
the cylinder and M.sub.2,particle will refer to magnetization
perpendicular to the long axis of the cylinder.
[0022] Disclosed embodiments are directed to a method and apparatus
of actuating magnetic particles in which the translational and
rotational motions may be decoupled, wherein rotational
manipulation is achieved by application of a rotating magnetic
field with zero or negligible field gradient
(H.sub.rotating-zero-gradient) and translational motion may be
achieved by application of a rotating magnetic field gradient
(H.sub.rotating-with-gradient) that is aligned parallel or
antiparallel to the overall magnetic field of a ferromagnetic
particle (H.sub.particle). A ferromagnetic particle, similar to a
common bar magnet, has an associated overall magnetic field
(H.sub.particle). The particle's overall magnetic field
(H.sub.particle) is generated by the magnetic domains contained
within the particle. Parallel alignment of any magnetic field
gradient (H.sub.gradient) and the overall particle magnetization
(M.sub.particle) will induce the particle to move in the direction
of decreasing gradient, i.e. away from the source of the magnetic
gradient (H.sub.gradient). Antiparallel alignment of the magnetic
field gradient (H.sub.gradient) and the overall particle
magnetization (M.sub.particle) will induce the particle to move in
the direction of increasing gradient, i.e. towards the source of
the magnetic gradient.
[0023] In accordance with disclosed embodiments, a ferromagnetic
particle with dimensions between 100 micrometers and 10 nanometers
may be made to rotate around one of its axes as a result of a
rotating, uniform, applied magnetic field with zero or negligible
magnetic gradient (H.sub.rotating-zero-gradient).
[0024] In accordance with disclosed embodiments, rotation of the
particle and rotation of the magnetic field
(H.sub.rotating-zero-gradient) may be in phase or out of phase with
one another.
[0025] In accordance with disclosed embodiments, the composition of
the particle may embody many different materials or objects loaded
into or onto the particle. These materials or objects may include
drugs, proteins, other particles, molecules, or cells. The particle
may also include electronic components, including capacitors,
resistors, diodes, transistors, or energy-scavenging devices such
as glucose fuel cells. Alternatively, disclosed embodiments may use
a superparamagnetic particle that may be partially coated with a
ferromagnetic component. In the case of a superparamagnetic
cylinder coated with a ferromagnetic component, the ferromagnetic
component may have magnetic moments perpendicular to the long axis
of the particle.
[0026] Disclosed embodiments may be implemented in whole or in part
to enable rotation of particles for the generation of bubbles
and/or vacuum (e.g., cavitation) in close proximity to the
particle, utilized in imaging the particle by increasing its
effective conspicuity during observation by magnetic resonance,
ultrasound, or other known imaging techniques, or used to derive
perpendicular magnetizations on a single particle by tuning a
length of magnetic sections on a cylindrical particle. The particle
may have multiple ferromagnetic or superparamagnetic segments on
the same particle. These segments may be magnetically distinct
regions, meaning they are separated by a diamagnetic material and
that their magnetic domains (M.sub.1,particle and M.sub.2,particle)
are independent of one another. Orthogonal magnetization on a
single particle refers to a particle having magnetic segments whose
magnetic domains (which generate M.sub.1,particle and
M.sub.2,particle generate magnetic fields that exist at an angle of
ninety degrees with respect to one another.
[0027] Non-contact manipulation of particles can be conventionally
achieved by applying magnetic fields to magnetizable particles, as
taught by D. L. Fan et al. in the publication titled "Controllable
High-Speed Rotation of Nanowires" in the journal Physical Review
Letters, Vol. 94, article 247208, June 2005 (incorporated herein by
reference in its entirety). Early work on the topic of rotating
millimeter scale magnetic materials and devices has focused on
chiral materials, as envisioned by K. Ishiyama et al. in their
publication "Swimming micro-machine driven by magnetic torque",
published in Sensors and Actuators A, Volume 91, pages 141-144,
2001 (incorporated herein by reference in its entirety).
[0028] Various papers have demonstrated micro- and nanoscale drills
by rotating helical structures, as taught by Ambharish Ghosh and
Peer Fischer in the publication "Controlled Propulsion of
Artificial Magnetic Nanostructured Propellers", published in the
journal Nano Letters, Vol. 9(6), pages 2243-2245, 2009
(incorporated herein by reference in its entirety), and Kathrin E.
Peyer et al. in the publication "Magnetic Helical Micromachines" in
the journal Chemistry A European Journal, Vol. 19, pages 28-38,
2013 (incorporated herein by reference in its entirety).
[0029] In prior art, rotation of the helical particles was
accomplished by applying a rotating, uniform magnetic field
(H.sub.rotating-zero-gradient) to the particles. In the cases of
the aforementioned microhelical devices (Ghosh and Fischer 2009,
Peyer et al. 2013), orientation of the magnetic field
(H.sub.rotating-zero-gradient) is in a direction orthogonal to the
particle's intended direction of translation. Additionally, in the
cases of microhelical devices, rotation of the device induces
translation of the device.
[0030] Further, it has been taught by Brandon H. McNaughton et al.
in the publication "Sudden Breakdown in Linear Response of a
Rotationally Driven Magnetic Microparticle and Application to
Physical and Chemical Microsensing" in the Journal of Physical
Chemistry B, Volume 110 (38), 2006, pages 18958-18964 (incorporated
herein by reference in its entirety), that a magnetic particle in a
rotating magnetic field (H.sub.rotating-zero-gradient) will remain
in phase with the magnetic field up to the point at which the
magnetic field is not strong enough to drive the rotation of the
particle in phase. A rotating magnetic field
(H.sub.rotating-zero-gradient) driving rotating motion in a
particle must overcome the force of viscous drag on the particle
for the particle to remain in phase with the rotating magnetic
field. Because the drag force increases with the rotational
velocity of the particle, there exists some frequency at which a
given rotating magnetic field becomes insufficient to continue
driving rotational motion of the particle in phase with the
rotating magnetic field.
[0031] When the drag force on the particle becomes larger than the
driving force generated by the rotating magnetic field, the
particle rotation slips out of phase with the driving magnetic
field rotation. This limit is called the "critical slipping point".
The point at which critical slipping occurs is due to several
factors, primarily the drag imposed on the particle by the
surrounding fluid(s) or material(s), the strength of the rotating
magnetic field, and the overall magnetic properties of the
particle.
[0032] With this understanding of the prior art in mind, disclosed
embodiments rotate particles in phase with a rotating magnetic
field, or out of phase with a rotating magnetic field. Controlled
rotation of the particle out of phase with the rotating magnetic
field is possible by applying a rotating magnetic field.
[0033] Previous applications of magnetically actuated particles as
taught by Ghosh et al. and Peyer et al. employed helical coils that
relied for propulsion on the coupling of translational and
rotational motion. To the contrary, the presently disclosed
embodiments provide a method and apparatus of actuating magnetic
particles in which the translational and rotational motions may be
decoupled.
[0034] In this disclosure, it should be understood that geometry
described herein and vocabulary used herein are particular to this
disclosure. For example, the phrase "major axis" and "minor axis"
refer to the axial and radial axes of a cylinder, respectively. The
major axis connects the two centers of the bases of the cylinder.
The radial axis sits at the midpoint between the two bases of the
cylinder, and is parallel to the bases of the cylinder. The
cylinder may have any aspect ratio, however for simplicity, the
term "major axis" always refers to the axis that connects the
centers of the faces of the cylinder. Note that for cylinders that
are not right circular cylinders, this major axis may not be
perpendicular to the cylinder bases.
[0035] FIGS. 1-4 illustrate an embodiment wherein rotational
manipulation is achieved by application of a rotating field with
zero or negligible field gradient. The rotating field may be
supplied by permanent magnets of electromagnetics. Rotational
frequencies of 100 Hz to 1000 Hz, or other values, may be applied.
In this embodiment, translational motion may be achieved by
application of a rotating magnetic field
(H.sub.rotating-zero-gradient) that is aligned parallel to the
magnetic field of a ferromagnetic particle (H.sub.particle). In
this orientation the rotation of the particle is induced by the
rotating magnetic field. Particle rotation only is achieved when
the particle's magnetic field (H.sub.particle) is in phase with the
rotating magnetic field (H.sub.rotating-zero-gradient). Particle
rotation and translation are achieved when the particle's magnetic
field (H.sub.particle) is out of phase with the rotating magnetic
field (H.sub.rotating-zero-gradient) by 180 degrees.
[0036] When the rotating magnetic field
(H.sub.rotating-zero-gradient) is adjusted such that it is out of
phase with the particle magnetic field (H.sub.particle) by 180
degrees, the rotating magnetic field's magnetic north is aligned
with the particle's magnetic north. The alignment of the rotating
magnetic field's "magnetic north" and the particle's "magnetic
north" generates a repulsive force that moves the particle away
from the source of the rotating magnetic field. The rotating
magnetic field's magnetic south direction operates likewise on the
particle's magnetic south field. In this configuration, the
particle is directed away from the source of the rotating magnetic
field, in the direction of decreasing gradient. In this embodiment,
the cylinder is diametrically magnetized. Diametric magnetization
occurs when the magnetic moment of the cylinder is aligned in a
plane parallel to the faces of the cylinder. As a result, the
particle is magnetized in the direction of the minor axis of the
cylinder.
[0037] As shown in FIGS. 1-4, the particle is cylindrical in shape
and the particle is diametrically magnetized. However, it should be
understood that the same principle could apply to many particle
shapes and to particles that are otherwise magnetized.
[0038] Moreover, it should be understood that, although a single
particle is illustrated in FIGS. 1-4, the disclosed embodiments
apply to the manipulation of a plurality of such particles
(regardless of shape), for example, an assembly of many such
particles.
[0039] In accordance with disclosed embodiments, a particle in the
nanoscale regime (e.g., 30 nm or less) or larger may be made to
rotate around one of its axes as a result of a uniform, rotating
magnetic field with zero or negligible magnetic gradient
(H.sub.rotating-zero-gradient).
[0040] While [0023] describes an embodiment of the invention in
which the driving rotating magnetic field
(H.sub.rotating-zero-gradient) is out of phase with the particle's
magnetic field (H.sub.particle) by 180 degrees, other embodiments
may include the particle's magnetic field (H.sub.particle) being
out of phase by some other number of degrees.
[0041] As illustrated in FIGS. 1-4, disclosed embodiments utilize
at least one particle 130 that embodies at least one magnetic or
magnetizable component 140. Particle 130 may be composed of
polymers, metals, insulators, semiconductors, ceramics,
nanomaterials, or any combinations of these materials.
Additionally, particle 130 may be solid, hollow, porous, biphasic,
multiphasic, coaxial, or any mixture of these structures. The
particle 130 may contain at least one magnetizable section 140
which, for the purposes of illustration, demonstrates magnetization
160 in the direction indicated by the open arrow 160 in FIGS. 1-4.
The letters "N" and "S" are used to represent "north" and "south"
magnetic poles, respectively, for the applied magnetic fields 150,
155 and the magnetic component of the particle 140.
[0042] Thus, FIGS. 1-4 represent a particle 130 in various magnetic
fields supplied by magnets 150, 155). Panels 10 (FIG. 1), 20 (FIG.
2), 30 (FIGS. 3), and 40 (FIG. 4) represent various points in time.
In the present disclosure, it should be understood that the
magnetization orientation of the particle 160 may be set through
the application of an initial magnetic field, shown in FIG. 1 panel
10, supplied by one or more magnets 150. Prior to being placed in
the particle manipulation apparatus, the magnetic or magnetizable
segment 140 of the particle may be magnetized, as shown in FIG. 1
panel 10. In the case of the cylindrical particle 130 shown in
FIGS. 1-4, the particle magnetization 160 may be in a direction
parallel to the face of the cylinder (diametric magnetization).
[0043] In a stationary magnetic field, such a particle 130 may
align with the magnetic field. In a sufficiently strong and
sufficiently slow rotating magnetic field
(H.sub.rotating-zero-gradient), the particle may rotate in phase
with the applied magnetic field at 20 (illustrated in FIG. 2). The
driving rotating magnetic field and the particle will remain in
phase for a given magnetic field, at a given viscosity (surrounding
the particle), and a given maximum driving rotating magnetic field
(H.sub.rotating-zero-gradient) frequency. In this configuration at
time 20, the particle 130 will remain oriented anti-parallel to,
and in phase with, the rotating applied magnetic
(H.sub.rotating-zero-gradient) field 155. As the rotating applied
magnetic field 155 (H.sub.rotating-zero-gradient) is driven by a
power source, the rotational frequency of the rotating applied
magnetic field (H.sub.rotating-zero-gradient) may range from less
than 100 Hz to more than 1000 Hz.
[0044] The rotational frequency of the particle is driven by the
rotating magnetic field (H.sub.rotating-zero-gradient), and is
subject to the physical constraints placed on it by the viscosity
of the surrounding material, the strength of the magnetic field,
and the magnetic properties of the particle. Particle rotation
occurring at 20 may be achieved by a rotating magnetic field
(H.sub.rotating-zero-gradient) that has a negligible field
gradient. During in-phase rotation at time 20, the magnetic segment
140 of the particle may be aligned anti-parallel 160 to the
rotating applied magnetic field 155. As a result, the particle only
rotates. As a result, in accordance with disclosed embodiments,
translational motion is decoupled from rotational motion. For the
purpose of describing the disclosed embodiments, the term
"decoupled rotation and translation" of a particle means that
rotation and translation can be independently controlled externally
to the particle, without substantially changing the shape of the
particle.
[0045] In accordance with disclosed embodiments, translational
motion may be achieved by changing two parameters of the applied
rotating magnetic field. In such an implementation, at 30
(illustrated in FIG. 3), the rotational frequency of the rotating
magnetic field 155 may be adjusted so that the particle 130 trails
the rotating magnetic field 165 by approximately 180 degrees. This
can be accomplished by various means, including: increasing the
rotating field frequency, decreasing the magnetic field strength,
or increasing the viscosity of the material surrounding the
particle to increase the drag on the particle as it rotates.
Because the rotating magnetic field and the particle's magnetic
field are out of phase by approximately 180 degrees, the driving
rotating magnetic field and the particle's magnetic field
(H.sub.particle) may be aligned parallel to one another.
[0046] Subsequently, at time 40 (FIG. 4), a magnetic gradient 190
may be added to the rotating magnetic field 155. As a result, there
may be a repulsive force produced that moves the particle in a
direction perpendicular to the vector of the particle's
magnetization 165. The repulsive force may be in the direction of
decreasing magnetic gradient, as illustrated in FIGS. 1-4. As a
result, in accordance with the disclosed embodiments, the rotating
magnetic field may drive the particle rotation, and the field
gradient may induce translational motion. As a result, in
accordance with the disclosed embodiments, rotational motion can be
accomplished with or without inducing translational motion.
[0047] In accordance with the disclosed embodiments, magnetic
fields may be applied by an apparatus of electromagnets and/or
permanent magnets described in part or in whole by prior inventions
of Dr. Irving Weinberg, including those disclosed in U.S. Pat. Nos.
8,466,680 and 8,154,286 (incorporated by reference herein in their
entireties), and related patent applications (by cross-reference,
priority or incorporation) filed by the same.
[0048] For example, as taught in those disclosures, applied
magnetic fields may have very short transition times so as not to
cause unpleasant sensations in a body. More specifically, in a
prior U.S. patent application Ser. No. 14/873,738 by Aleksandar N.
Nacev and Irving N. Weinberg, entitled "Pulsed Gradient Field
Method to Counteract a Static Magnetic Field for Magnetic Particle
Focusing", filed on Oct. 2, 2015 (incorporated by reference in its
entirety), a strategy for propelling particles was disclosed in
which magnetizable particles were first polarized and/or aligned in
one direction, and then within a short time (e.g., less than the
time it would take for polarization to decay) a magnetic field in
another direction was applied to the initially polarized particles.
As disclosed by Nacev and Weinberg, this strategy could be applied
multiple times.
[0049] Disclosed embodiments may also be implemented in conjunction
with techniques disclosed in US Pat. Pub. 20140309479, entitled
"SYSTEM, METHOD AND EQUIPMENT FOR IMPLEMENTING TEMPORARY
DIAMAGNETIC PROPULSIVE FOCUSING EFFECT WITH TRANSIENT APPLIED
MAGNETIC FIELD PULSES" and filed on Feb. 18, 2014 (incorporated
herein by reference in its entirety). Therefore, it should be
understood that the disclosed embodiments may be implemented in
conjunction with the production and application of magnetic fields
to apply repulsive (e.g., diamagnetic) and/or propulsive (e.g.,
attractive) forces so as to manipulate one or more magnetizable
particles, for example by setting up appropriate magnetic gradient
fields with or without pre-polarizing pulses.
[0050] Additionally, the composition of the particle may embody
many different materials or objects loaded into or onto the
particle. These materials or objects may include drugs, proteins,
other particles, molecules, or cells. The particle may also include
electronic components, including capacitors, resistors, diodes,
transistors, or energy-scavenging devices such as glucose fuel
cells.
[0051] Alternatively, disclosed embodiments may use a
superparamagnetic particle that may be partially coated with a
ferromagnetic component. The ferromagnetic component may have
segments magnetized perpendicular to the long axis of the particle
(M.sub.2,particle). Such a configuration is illustrated in panel
201 illustrated in FIG. 5. In such an embodiment, a ferromagnetic
layer 340 may be, volumetrically, only 0.1% of the total volume of
the entire particle 300. In one implementation, the bulk of the
particle 300 may be composed of a superparamagnetic material having
magnetic moments 335 that are randomly oriented outside of a
magnetic field. Note that the superparamagnetic portion of the
particle 300 will have a segment, very near the ferromagnetic layer
340 that are aligned in parallel with the magnetization of the
ferromagnetic layer 340. The magnetic moments of the
superparamagnetic material are generally disordered outside of a
magnetic field. While the thin ferromagnetic layer 340 does provide
some local magnetic field, it is weak and only impacts a small
fraction of the magnetic moments of the bulk superparamagnetic
material of the particle. Thus, as shown in FIG. 6 the operation of
magnetizing the thin ferromagnetic layer magnetic moments 340 may
be performed by placing the particle 300 in a magnetic field
supplied by magnets 299. As a result, the superparamagnetic bulk
magnetic moments 335 of the particle 300 also align with the field.
However once the magnet is removed, the magnetization of the
superparamagnetic bulk also undergoes Neelian relaxation, as
illustrated in FIGS. 7-8.
[0052] In at least one embodiment, the particle may take the shape
of a cylinder that is longer than it is wide (e.g., aspect ratio
greater than 1). In this configuration, there may be interactions
among the magnetic moments of the bulk of the particle 300 that may
reinforce magnetic alignment of the particle 300 with an applied
magnetic field. This force may be in direct opposition to the
alignment behavior of the thin ferromagnetic layer 340.
[0053] In accordance with at least one disclosed embodiment, the
thin ferromagnetic layer magnetic moments 340 may be magnetized
diametrically 345 (M.sub.2,particle).sub.; thus, application of at
least some designed magnetic fields may induce the long axis of the
particle to align perpendicular to the magnetic field.
[0054] Moreover, in at least one embodiment of the invention, the
long axis of the particle may align antiparallel to the magnetic
field for one range of field strengths, and may align perpendicular
to the field in another range of field strengths. This may be due
to an energy balance of aligning the thin ferromagnetic segment
magnetic moments 340 or the bulk superparamagnetic segment magnetic
moments 335 of the particle 300 with the magnetic field. Alignment
with the superparamagnetic bulk of the particle 300 may prevail
when the impetus for dipole-dipole alignment in the
superparamagnetic bulk magnetic moments 335 of the particle
overcomes the energy barrier of aligning the thin ferromagnetic
layer 340 of the particle perpendicular to the magnetic field.
[0055] There are two modes of particle alignment. One mode may be
referred to as "bulk dominant" alignment mode. Another mode may be
referred to as "thin layer dominant" alignment. Bulk dominant
alignment and thin layer dominant alignment may result from the
application of magnetic fields by magnets 399. Magnets 399 may be
electromagnets, permanent magnets, or some combination of both.
During bulk dominant alignment, the long axis of the particle may
align with the applied magnetic field (illustrated in panel 301 of
FIG. 7). During thin layer dominant alignment, the long axis of the
particle may align perpendicular to the applied magnetic field
(illustrated at panel 302 of FIG. 8).
[0056] FIG. 4 illustrates a configuration provided in accordance
with the disclosed embodiments to provide a combination of rotation
and propulsion forces to a particle or many particles. As shown in
panel 410 of FIG. 9, all applied magnetic fields may be removed. As
a result, because the bulk of the particle 300 is
superparamagnetic, the magnetic moments 335 of the particle bulk
may undergo Neel relaxation 335. However, it should be understood
that the magnetic moments of the particle ferromagnetic layer
undergo negligible Neelian relaxation because they are
ferromagnetic.
[0057] Subsequently, at time or phase 420, a rotational magnetic
field 500 may be applied. This rotational magnetic field 500 may
make use of the thin layer dominant alignment mode. Thus, at 420
(FIG. 10), a magnetic field is applied that is orthogonal to the
long axis of the particle, and parallel to the magnetic moments of
the thin ferromagnetic segment 340. Thus, the magnetization of the
superparamagnetic segment 335 of the particle 300 may reorder to be
arranged perpendicular to the long axis of the particle.
[0058] However, significantly, the particle itself does not
reorient to align with the magnetic field as in 301 of FIG. 7; this
is because the rotational magnetic field 500 is significantly
weaker than the aligning magnetic field shown in 301 of FIG. 7.
Magnetic fields are additive, thus a rotating magnetic field
combined with an aligning magnetic field produces a precessing
magnetic field, where precession has some angle away from the axis
of the rotating magnetic field.
[0059] The aligning magnetic field shown in 301 of FIG. 7 may be
removed or attenuated and only the rotational magnetic field 500 is
present in FIG. 8. Thus, the energetic minimum of the system is
achieved by allowing the thin ferromagnetic segment 340 of the
particle 300 to be aligned with the rotating magnetic field 500
(H.sub.rotating-zero-gradient). As shown at 420 (FIG. 10) and 430
(FIG. 11), the particle 300 may be rotated around its long axis
because the rotational field 500 is rotated around the long axis of
the particle (dotted lines at 420, 430). After application of the
rotational field, the rotational field magnets may be removed and
the superparamagnetic magnetic moments 335 of the particle bulk may
be allowed to undergo Neelian relaxation.
[0060] Translational propulsion may be achieved, as shown in panel
440 (FIG. 12), by interleaving the rotating magnetic field 500
(H.sub.rotating-zero-gradient) applied in panels 420 (FIG. 10) and
430 (FIG. 10), with the propulsion magnetic field
(H.sub.zero-gradient) application shown in panels 450 (FIG. 13) and
460 (FIG. 14). By applying a strong magnetic field gradient
(H.sub.zero-gradient) using magnets 510, the superparamagnetic bulk
of the particle will have magnetic moments 335 that temporarily
align antiparallel to the strong alignment magnetic field produced
by a pair of magnets 510. It should be understood that the
alignment field produced by the magnets 510 in FIG. 13 could be
implemented through the application of electromagnets or permanent
magnets.
[0061] Overall physical alignment of the particle 300 in space may
be achieved by a strong aligning magnetic field. During the
application of the strong aligning magnetic field the
superparamagnetic moments 335 of the particle volume may
energetically favor aligning with the field along the long axis of
the particle 300. Due to the particle 300 being primarily composed
of superparamagnetic material, the energetic minimum may be
obtained by the particle 300 aligning with the strong aligning
magnetic field produced by magnets 510. To the contrary, the
ferromagnetic component 340 may have magnetic moments 345
orthogonal to the strong aligning magnetic field. This is due to
the overwhelming aligning force caused by the superparamagnetic
moments 335 of the particle bulk energetically favoring alignment
at 450 with the magnetic field.
[0062] Propulsion may be achieved by removal of the aligning
magnetic field magnets 510 (H.sub.zero-gradient) and applying a
fast pulse of magnetic field gradient (H.sub.with-gradient) in the
direction antiparallel 520 to the aligning magnetic field. The
result may be a propulsion force 530, similar to that previously
disclosed by Aleksandar Nacev and Irving Weinberg.
[0063] In such an embodiment, with reference to FIGS. 9-14,
operations performed in panels 410-460 may represent sequential
points in time. These operations may interleave the strong aligning
magnetic field and the rotational magnetic field to achieve
alignment and rotational manipulation of the particle at 430. Thus,
in at least this embodiment, rotation and translation may be
accomplished by interweaving magnetic pulses for sequentially
aligning the particle, translating the particle via a parallel or
antiparallel aligned magnetic field gradient (H.sub.with-gradient),
and rotating the particle with a rotating magnetic field having
zero or negligible gradient (H.sub.rotating-zero-gradient).
[0064] Applications of the disclosed embodiments are varied.
Tissues and fluids in the body are non-Newtonian materials with
viscoelastic properties that hinder motion of particles under
magnetic guidance. It is known that very small bubbles can alter
the motion of particles in viscous fluids, as taught by A. Maali
and B. Bhushan in the article entitled "Nanobubbles and their role
in slip and drag", published in the Journal of Physics: Condensed
Matter 25 (2013) pp. 184003 (incorporated by reference in its
entirety).
[0065] The presently disclosed embodiments may be implemented in
whole or in part to enable rotation of particles for the generation
of bubbles and/or vacuum (e.g., cavitation) in close proximity to
the particle. Cavitation may, thus, be used to lubricate the
particle, serving as a low resistance boundary between the particle
surface and surrounding media. In an additional embodiment,
cavitation may aid in imaging the particle by increasing its
effective conspicuity during observation by magnetic resonance,
ultrasound, or other known imaging techniques discussed in
references cited and incorporated herein.
[0066] In an additional embodiment, rotation may be utilized in
imaging the particle by increasing its effective conspicuity during
observation by magnetic resonance, ultrasound, or other known
imaging techniques discussed in references cited and incorporated
herein. For example, rotation of the particle may affect its
absorption or reflectance of energy impinging on the particle from
a source.
[0067] Additionally, disclosed embodiments may be utilized to
increase the coupling efficiency of sections of a particle to
applied magnetic fields by manufacturing one or more magnetic
sections of a particle with specified lengths or ratios of lengths.
As an example, as illustrated in FIG. 15, a cylinder with a
magnetic segment with a length more than twice the cylinder
diameter will have an easy axis of magnetization along the length
of the cylinder. The relationship of rod length to the ease of
magnetization in a particular direction is taught by Love et al. in
their publication "Three-Dimensional Self-Assembly of Metallic Rods
with Submicron Diameters Using Magnetic Interactions" published in
the Journal of the American Chemical Society 125, 12696-12697, 2003
(incorporated herein by reference in its entirety).
[0068] One method of accomplishing magnetic segments on cylinders
magnetized perpendicular to the long axis (M.sub.2,particle) of the
cylinder may be by making the magnetic segment shorter than the
diameter of the cylinder itself. Thus, cylinders with perpendicular
magnetizations M.sub.1,particle and M.sub.2,particle may be
manufactured by creating at least two magnetic segments on a single
cylinder, as illustrated in phase 700 of FIG. 15. Thus, one or many
magnetic segments with lengths of at least twice the cylinder
diameter 710 (M.sub.1,particle), and one or many segments with
lengths less than the cylinder diameter 720 (M.sub.2,particle) may
be provided, each magnetic segment being separated by non-magnetic
material 730. As illustrated in FIG. 15, arrows indicate the
direction of magnetization of each segment 710, 720.
[0069] FIG. 16 illustrates one example of operation of an apparatus
provided in accordance with the disclosed embodiments. As shown in
FIG. 16, a plurality (e.g., four) of electromagnets 903 are
provided with one permanent magnet 906 to manipulate the particle
905 in the prescribed manner. Note that the electromagnets in FIG.
16 may supply the magnetic field with zero or negligible gradient.
Also, note that the particle shown in FIG. 16 may have two
magnetizations embodied on the single particle. Each magnetization
direction is shown with an arrow on the body of the particle 905.
In operation, the apparatus incorporates and utilizes a computer
901 to generate a signal for driving the four electromagnets 903.
The computer 901 may be replaced by another signal generating
device capable of supplying current to electromagnets 903. For
example, a pulsed voltage supply may be used. The signal generated
by the computer 901 may be amplified by an amplifier 902, before
being sent to the electromagnets 903.
[0070] FIG. 16 further illustrates that the electromagnets may be
driven by a two-channel signal; however, the demonstration of two
channels is only intended to be exemplary. It should be understood
that the disclosed embodiments may include two electromagnets,
eight electromagnets, or more. Likewise, the electromagnets may be
driven by one channel of signal from computer 901 or other signal
generator, eight channels of signal from the computer 901 or other
signal generator, or more channels. Additionally, electromagnets
may be used to excite particles using RF pulses for heating the
particles to locally induce hyperthermia.
[0071] FIG. 16 demonstrates rotation around the long axis of the
rod 904 produced by the rotating field supplied by the
electromagnets 903. A permanent magnet 906 may be used to provide a
magnetic gradient. It should be understood that this magnetic
gradient may be generated using an electromagnet, and may vary in
amplitude and frequency over the course of time.
[0072] It should be understood that the operations explained herein
may be implemented in conjunction with, or under the control of,
one or more general purpose computers running software algorithms
to provide the presently disclosed functionality and turning those
computers into specific purpose computers.
[0073] Moreover, those skilled in the art will recognize, upon
consideration of the above teachings, that the above exemplary
embodiments may be based upon use of one or more programmed
processors programmed with a suitable computer program. However,
the disclosed embodiments could be implemented using hardware
component equivalents such as special purpose hardware and/or
dedicated processors. Similarly, general purpose computers,
microprocessor based computers, micro-controllers, optical
computers, analog computers, dedicated processors, application
specific circuits and/or dedicated hard wired logic may be used to
construct alternative equivalent embodiments.
[0074] Moreover, it should be understood that control and
cooperation of components (e.g., magnets) of an instrument for
applying magnetic fields described herein to manipulate one or more
particles may be provided using software instructions that may be
stored in a tangible, non-transitory storage device such as a
non-transitory computer readable storage device storing
instructions which, when executed on one or more programmed
processors, carry out the above-described method operations and
resulting functionality. In this case, the term non-transitory is
intended to preclude transmitted signals and propagating waves, but
not storage devices that are erasable or dependent upon power
sources to retain information.
[0075] Accordingly, such an instrument may include one or more
controllable electromagnetic field sources and a controller that
enables control of resulting magnetic fields as described herein.
In one such implementation, one or more gradient coils may be
utilized under the control of a controller to enables control of
the gradient to produce one or magnetic fields using at least one
coil driver, wherein one or more coils are provided for
transmitting RF energy into a tissue sample of a body part as part
of diagnostic, prognostic, and/or treatment
[0076] Those skilled in the art will appreciate, upon consideration
of the above teachings, that the program operations and processes
and associated data used to implement certain of the embodiments
described above can be implemented using disc storage as well as
other forms of storage devices including, but not limited to
non-transitory storage media (where non-transitory is intended only
to preclude propagating signals and not signals which are
transitory in that they are erased by removal of power or explicit
acts of erasure) such as for example Read Only Memory (ROM)
devices, Random Access Memory (RAM) devices, network memory
devices, optical storage elements, magnetic storage elements,
magneto-optical storage elements, flash memory, core memory and/or
other equivalent volatile and non-volatile storage technologies
without departing from certain embodiments of the present
invention. Such alternative storage devices should be considered
equivalents.
[0077] In accordance with at least one embodiment, apparatuses and
methods are provided for rotating and translating a particle, in
which at least some portion or component of the particle contains a
magnetizable material, and in which the rotation of the particle is
decoupled from the translational motion of the particle. For the
purposes of this disclosure, the term "decoupled" is intended to
mean the ability to vary the ratio between the translational
velocity and the rotational velocity of the particle. This
decoupling is different from the prior art, for example in which
magnetic particles have been manufactured or configured in screw or
arc shape so as to drill into or through a medium. In that example,
the ratio of translational velocity to the rotational velocity is
not variable, since it is set by the geometric configuration of the
screw or arc. An example of the prior art was presented by UK
Cheang, F Meshkali, D Kim, M J Kim, and H C Fu, at the 2014 article
of the journal Physical Review E (volume 90, 033007), entitled
"Minimal geometric requirements for micrpropulsion via magnetic
rotation".
[0078] In accordance with at least one embodiment, the particle may
have segments with features having dimensions on the order of 1
nanometer or more in any dimension.
[0079] In accordance with at least one embodiment, the rotational
field applied to the particle may range from 1 Hz to 1000 Hz.
[0080] In accordance with at least one embodiment, electromagnets
used to manipulated particles may be operated so as to generate
alternating magnetic fields. The electromagnets may be operated at
radio frequencies, and the operation may be used to excite rapid
changes in the magnetic domains of the particles. The rapid changes
in the particle's magnetic domains may be used to convert the
rapidly switching magnetic energy into thermal energy, emitted from
the particle.
[0081] In accordance with at least one embodiment, the particle may
be composed of polymeric, metallic, insulating, semiconducting,
ceramic, or any combinations of these materials. In accordance with
at least one embodiment, the particle may house electronics,
molecules/drugs, proteins, cells, or energy scavenging
components.
[0082] In accordance with at least one embodiment, the particles
may carry segments capable of emitting light (for example by
carrying phosphorescent material), or are capable of being heated
using RF fields for supplying thermal energy for hyperthermia
treatments. Magnetic particle induced hyperthermia is the process
by which alternating magnetic fields are used to excite magnetic
particles placed in a human or animal body. Alternating field
excitation may be performed at radio frequencies. Particle
excitation induces particle heating. This heating may be used to
damage or kill cells in the vicinity of the particles. By
localizing the magnetic particles using magnetic fields and field
gradients, the released thermal energy can be targeted to the
region around the particles, as taught by Andre C. Silva et al., in
the publication "Application of hyperthermia induced by
superparamagnetic iron oxide particles in glioma treatment,"
published in the International Journal of Nanomedicine, Volume 6,
pages 591-603, 2011.
[0083] In accordance with at least one embodiment, rotation of the
particle reduces effective resistance to motion. A reduction in the
effective resistance to motion may be achieved by locally reducing
the effective viscosity of the surrounding biological materials,
tissues, or fluids. For example, tissue is a shear thinning
material. This means that the effective viscosity of tissue
decreases as the shear applied to the tissue increases. Rotation of
the particle generates a shear force around the particle, and this
shear force may decrease the effective viscosity of the tissue
surrounding the particle. Additionally, the applied shear force may
result in barriers to motion, such as dense agglomerations of
proteins or plaques, to be moved due to the induced shear force.
Alternatively, the shear force may be used to induce translation of
the particle in a direction perpendicular to the direction of
translation.
[0084] In accordance with at least one embodiment, rotation of the
particle increases conspicuity under imaging. In accordance with at
least one embodiment, a solution contains multiple particles and/or
multiple different types of particles, i.e., collections of
particles housing electronics, and/or collections of particles
containing molecules/drugs, and/or collection of particles
operating as energy scavenging components. In accordance with at
least one embodiment, rotation of the particle increases
translational velocity in a medium. The medium may be Newtonian or
non-Newtonian. In accordance with at least one embodiment, if the
particle is carrying a payload (e.g., a drug), then rotation of the
particle modifies the rate of release of the payload. In accordance
with at least one embodiment, rotation of the particle modifies the
rate or mode of degradation of the particle, for example by
stressing the junctions between portions of the particle.
[0085] Illustrated embodiments include an apparatus for rotating
and translating at least one particle, the apparatus comprising:
means for generating magnetic force and torque; and at least one
particle, wherein at least some portion of the at least one
particle contains a magnetizable material, wherein the generated
magnetic force is applied to at least some portion of the at least
one particle to cause translational motion of the particle, wherein
the generated magnetic torque is applied to at least some other
portion of the same at least one particle to cause rotation of the
particle, and wherein the ratio of the translational and rotational
velocities of the particle is varied.
[0086] Illustrated embodiments include such an embodiment, wherein
the particle is introduced in a body, and a ratio of the
translational and rotational velocities of the particle is varied
while the particle is in the body.
[0087] Illustrated embodiments include such an embodiment, wherein
the means for generating magnetic force includes means for
generating a rotational field ranging from 1 Hz to 1000 Hz.
[0088] Illustrated embodiments include such an embodiment, wherein
the at least one particle is composed of polymeric, metallic,
insulating, semiconducting, ceramic, or combinations of at least
two of these materials.
[0089] Illustrated embodiments include such an embodiment, wherein
the at least one particle houses electronics, molecules/ drugs,
proteins, cells, or energy scavenging components.
[0090] Illustrated embodiments include such an embodiment, wherein
the at least one particle carries segments capable of emitting
light.
[0091] Illustrated embodiments include such an embodiment, wherein
the at least one particle is capable of being heated using
radiofrequency radiation.
[0092] Illustrated embodiments include such an embodiment, wherein
the at least one particle is capable of being heated using
alternating magnetic fields.
[0093] Illustrated embodiments include such an embodiment, wherein
the at least one particle is capable of carrying a payload.
[0094] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle reduces effective resistance
to motion.
[0095] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle increases conspicuity under
imaging.
[0096] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle increases translational
velocity in a medium.
[0097] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle modifies release of a payload
contained in the at least one particle.
[0098] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle modifies degradation of the
at least one particle.
[0099] Illustrated embodiments include such an embodiment, wherein
at least one of the rotation of the at least one particle and the
decoupled translational motion of the at least one particle are
implemented in conjunction with the production and application of
magnetic fields to apply repulsive and/or propulsive forces so as
to manipulate the at least one particle. Illustrated embodiments
include such an embodiment, wherein manipulation of the at least
one particle is performed by setting up appropriate magnetic
gradient fields with or without pre-polarizing pulses.
[0100] Illustrated embodiments include such an embodiment, further
comprising a solution that contains a plurality of particles
including the at least one particle, wherein each particle of the
plurality of particles includes some portion or component that
contains a magnetizable material, wherein magnetic torque causing
rotation of each of the plurality of particle is decoupled from the
magnetic force causing translational motion.
[0101] Illustrated embodiments include such an embodiment, where an
amplitude and frequency of a magnetic field causing rotation of the
at least one particle is independent of an amplitude and frequency
of a magnetic gradient that is causing translation of the at least
one particle. Illustrated embodiments include such an embodiment,
wherein the amplitude of the magnetic gradient used to induce the
at least one particle translation is constant in time. Similarly,
illustrated embodiments include such an embodiment, wherein the
amplitude of the magnetic gradient changes in time.
[0102] Illustrated embodiments include a method for rotating and
translating at least one particle, the method comprising:
generating and applying a magnetic force and torque upon at least
one particle, wherein the at least one particle includes at least
two segments, each of which contains a magnetizable material;
applying the magnetic force to at least one segment in order to
cause translational motion of the particle; and applying the
magnetic torque to at least one other segment in order to cause
rotational motion of the particle, wherein a ratio of the resultant
translational and rotational velocities of the particle is
varied.
[0103] Illustrated embodiments include such an embodiment, wherein
the particle is introduced in a body, and a ratio of the
translational and rotational velocities of the particle is varied
while the particle is in the body.
[0104] Illustrated embodiments include such an embodiment, wherein
the generation of the magnetic force generates a rotational field
ranging from 1 Hz to 1000 Hz.
[0105] Illustrated embodiments include such an embodiment, wherein
the at least one particle is composed of polymeric, metallic,
insulating, semiconducting, ceramic, or combinations of at least
two of these materials.
[0106] Illustrated embodiments include such an embodiment, wherein
the at least one particle houses electronics, molecules/ drugs,
proteins, cells, or energy scavenging components.
[0107] Illustrated embodiments include such an embodiment, wherein
the at least one particle carries segments capable of emitting
light.
[0108] Illustrated embodiments include such an embodiment, wherein
the at least one particle is capable of being heated using
radiofrequency radiation.
[0109] Illustrated embodiments include such an embodiment, wherein
the at least one particle is capable of being heated using
alternating magnetic fields.
[0110] Illustrated embodiments include such an embodiment, wherein
the at least one particle is capable of carrying a payload.
[0111] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle reduces effective resistance
to motion.
[0112] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle increases conspicuity under
imaging.
[0113] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle increases translational
velocity in a medium.
[0114] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle modifies release of a payload
contained in the at least one particle.
[0115] Illustrated embodiments include such an embodiment, wherein
rotation of the at least one particle modifies degradation of the
at least one particle.
[0116] Illustrated embodiments include such an embodiment, wherein
at least one of the rotation of the at least one particle and the
decoupled translational motion of the at least one particle are
implemented in conjunction with the production and application of
magnetic fields to apply repulsive and/or propulsive forces so as
to manipulate the at least one particle.
[0117] Illustrated embodiments include such an embodiment, wherein
manipulation of the at least one particle is performed by setting
up appropriate magnetic gradient fields with or without
pre-polarizing pulses.
[0118] Illustrated embodiments include such an embodiment, wherein
the at least one particle is one of a plurality of particles,
wherein each particle of the plurality of particles includes some
portion or component that contains a magnetizable material, wherein
magnetic torque causing rotation of each of the plurality of
particle is decoupled from the magnetic force causing translational
motion.
[0119] Illustrated embodiments include such an embodiment, wherein
a solution that contains a plurality of particles including the at
least one particle, wherein each particle of the plurality of
particles includes some portion or component that contains a
magnetizable material, wherein magnetic torque causing rotation of
each of the plurality of particle is decoupled from the magnetic
force causing translational motion.
[0120] Illustrated embodiments include such an embodiment, wherein
an amplitude and frequency of a magnetic field causing rotation of
the at least one particle is independent of an amplitude and
frequency of a magnetic gradient that is causing translation of the
at least one particle. Illustrated embodiments include such an
embodiment, wherein the amplitude of the magnetic gradient used to
induce the at least one particle translation is constant in time.
Similarly, illustrated embodiments includes such an embodiment,
wherein the amplitude of the magnetic gradient changes in time.
[0121] While certain illustrative embodiments have been described,
it is evident that many alternatives, modifications, permutations
and variations will become apparent to those skilled in the art in
light of the foregoing description. While illustrated embodiments
have been outlined above, it is evident that many alternatives,
modifications and variations will be apparent to those skilled in
the art. Accordingly, the various embodiments of the invention, as
set forth above, are intended to be illustrative, not limiting.
Various changes may be made without departing from the spirit and
scope of the invention.
[0122] As a result, it will be apparent for those skilled in the
art that the illustrative embodiments described are only examples
and that various modifications can be made within the scope of the
invention as defined in the appended claims.
* * * * *