Decoupled Magnetic Particle Rotation and Translation Control

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Solution Overview

Problem

Existing methods for manipulating magnetic particles fail to decouple translational and rotational motions, leading to limitations in independent control of particle movement and efficiency, particularly due to the coupling of motions in previous applications.

Innovation Solution

The method and apparatus utilize rotating magnetic fields with zero or negligible gradients for rotational motion and rotating magnetic field gradients for translational motion, allowing for independent control of particle rotation and translation, using a combination of permanent magnets and electromagnets to generate the necessary fields and gradients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single magnetic field is used to manipulate particles, then the manipulation is simple, but translational and rotational motions are coupled and cannot be controlled independently

Engineering Contradiction:
Improveindependent control of particle motionVSAvoidmagnetic field generation system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The magnetic field generation system is segmented into two independent subsystems: one for producing translational motion (using magnetic field gradients) and another for producing rotational motion (using rotating magnetic fields). This segmentation allows independent control of particle translation and rotation, resolving the coupling problem while maintaining operational simplicity through modular control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The magnetic field generation apparatus is designed with multi-functionality, where the same system can independently produce both translational magnetic field gradients and rotational magnetic fields. This universal design enables a single apparatus to perform multiple manipulation functions without requiring separate systems, balancing device complexity with operational flexibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Speed

If magnetic fields are used to induce particle rotation, then rotational motion is achieved, but translational control is lost due to field coupling

Engineering Contradiction:
Improveparticle rotation speedVSAvoidtranslational control
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The control system is segmented into independent rotational control and translational control channels. The rotational channel uses rotating magnetic fields to control particle spin speed, while the translational channel uses magnetic field gradients to control particle position. This segmentation eliminates the coupling effect, allowing full translational control to be maintained even during high-speed rotation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the magnetic field parameters independently for rotation and translation. The rotational magnetic field frequency and amplitude can be varied to control rotation speed, while the gradient field strength is independently adjusted to maintain translational control, enabling dynamic adaptation without coupling interference.

Inventive Principle:
Principle #15Dynamics

3Speed

If magnetic field gradients are used for particle translation, then translational motion is achieved, but rotational control is lost

Engineering Contradiction:
Improveparticle translation speedVSAvoidrotational control
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The magnetic field generation system is divided into independent translational and rotational subsystems. The translational subsystem generates magnetic field gradients for particle translation, while the rotational subsystem generates rotating magnetic fields for particle rotation. This segmentation allows both translation and rotation to be controlled independently, resolving the mutual exclusion problem.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system merges the translational and rotational magnetic field generation capabilities into a unified apparatus that operates independently in both modes. By combining the functionality while maintaining independent control channels, the system achieves both high-speed translation and precise rotational control without sacrificing either capability.

Inventive Principle:
Principle #5Merging (Combining)

4Productivity

If conventional magnetic manipulation methods are used, then particle movement is achieved, but viscous drag significantly limits manipulation efficiency

Engineering Contradiction:
Improvemanipulation efficiencyVSAvoidenergy loss to viscous drag
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The system applies oscillating and rotating magnetic fields that induce vibrational and rotational motion in magnetic particles. This mechanical vibration approach enables particles to overcome viscous drag more effectively, enhancing manipulation efficiency in viscous environments by reducing the energy loss to drag forces through dynamic motion patterns.

Inventive Principle:
Principle #18Mechanical vibration

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables precise and independent manipulation of magnetic particles, allowing for simultaneous or decoupled rotation and translation, enhancing control over particle motion and reducing the impact of viscous drag, thereby overcoming the limitations of previous technologies.

Implementation Method 1

rotational manipulation is achieved by application of a rotating field with zero or negligible field gradient

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

application of a rotating field with zero or negligible field gradient (H rotating-zero-gradient) and translational motion is achieved by application of a rotating magnetic field gradient (H rotating-with-gradient) that is aligned parallel or antiparallel to the overall magnetic field of a ferromagnetic particle (H particle)

Methodology Applied
Scientific EffectMagnetic torque: Torque

Implementation Method 3

translational motion is achieved by application of a rotating magnetic field gradient (H rotating-with-gradient) that is aligned parallel or antiparallel to the overall magnetic field of a ferromagnetic particle (H particle)

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Implementation Method 4

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

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 5

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)

Methodology Applied
Scientific EffectNeelian relaxation: Magnetic Hysteresis

Data Source

PatentEP3212284B1Method and apparatus for non-contact axial particle rotation and decoupled particle propulsion
Publication Date: 2021.07.07 WEINBERG MEDICAL PHYSICS INC
  • EP3212284B1 patent drawingFigure 1
  • EP3212284B1 patent drawingFigure 2
  • EP3212284B1 patent drawingFigure 3

AI summary

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.