Related Experiment Video

Updated: Jul 27, 2025

Aqueous Droplets Used as Enzymatic Microreactors and Their Electromagnetic Actuation
08:27

Aqueous Droplets Used as Enzymatic Microreactors and Their Electromagnetic Actuation

Published on: August 28, 2017

5.4K

Threshold magnetic field as a universal criterion for the selective transport of magnetized particles in

Shinji Bono1,2,3,4, Satoshi Konishi5,6,7,8

  • 1Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, 525-8577, Japan. bono@fc.ritsumei.ac.jp.

Scientific Reports
|June 9, 2023
PubMed

Insights

Magnetized particles (MPs) can be transported against gravity using a magnetic field. This study demonstrates selective separation of MPs in microdroplets based on their magnetic properties, offering a universal criterion for manipulating magnetized targets.

Area of Science:

  • Physics
  • Biotechnology
  • Materials Science

Background:

  • Transporting magnetized particles (MPs) against gravity requires overcoming gravitational forces.
  • Quantitative assessment of forces is crucial for understanding MP behavior in microfluidic systems.

Purpose of the Study:

  • To investigate the selective transportation of MPs in microdroplets.
  • To determine the threshold magnetic field required for anti-gravity transport.
  • To establish a universal criterion for selective manipulation of magnetized targets.

Main Methods:

  • Applying an external magnetic field to MPs within microdroplets.
  • Modulating the intensity of the applied magnetic field.
  • Quantitatively analyzing the transport dynamics and forces acting on MPs.

Main Results:

  • MPs were transported against gravity when the applied magnetic field exceeded a specific threshold value.
  • Selective separation of MPs into different microdroplets was achieved based on their magnetic properties.
  • The threshold magnetic field was found to depend solely on the magnetic susceptibility and density of the MPs.

Conclusions:

  • A universal criterion based on magnetic susceptibility and density enables selective transport of MPs in microdroplets.
  • This method provides a foundation for manipulating magnetized targets, including cells, in microfluidic environments.

More Related Videos

Computer Numerical Control Micromilling of a Microfluidic Acrylic Device with a Staggered Restriction for Magnetic Nanoparticle-Based Immunoassays09:58

Computer Numerical Control Micromilling of a Microfluidic Acrylic Device with a Staggered Restriction for Magnetic Nanoparticle-Based Immunoassays

Published on: June 23, 2022

2.2K
Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains07:42

Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains

Published on: July 20, 2022

2.8K

Related Concept Videos

Paramagnetism01:30

Paramagnetism

Paramagnets are materials with unpaired electrons that possess a finite magnetic moment. In the absence of a magnetic field, these moments are randomly oriented, and thus the net moment is zero. Under an external field, a torque acting on the moments tends to align them along the field's direction. However, the random thermal motion of electrons produces a torque opposite to the external field and tries to disorient the moments. These two competing effects align only a few moments along the...
2.6K
Diamagnetism01:26

Diamagnetism

Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
2.5K
Magnetic Susceptibility and Permeability01:31

Magnetic Susceptibility and Permeability

In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
1.2K
Ferromagnetism01:31

Ferromagnetism

Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.4K
Potential Due to a Magnetized Object01:24

Potential Due to a Magnetized Object

Magnetic dipoles in magnetic materials are aligned when placed under an external magnetic field. For paramagnets and ferromagnets, dipole alignment occurs in the direction of the magnetic field. However, the dipoles align opposite to the field in the case of diamagnets. This state of magnetic polarization due to the external field is called magnetization. Magnetization is defined as the dipole moment per unit volume. It plays a similar role to polarization in electrostatics.
The vector...
323
Magnetic Field due to Moving Charges01:23

Magnetic Field due to Moving Charges

A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
8.9K