Related Experiment Video
Updated: Jan 23, 2026

Paramagnetic Relaxation Enhancement for Detecting and Characterizing Self-Associations of Intrinsically Disordered Proteins
Published on: September 23, 2021
Measurement of the magnetic susceptibility of subtle paramagnetic solutions using the diamagnetic repulsion of
Bong Hwan Jang1, Seyong Kwon1, Joo H Kang1
1Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea. jookang@unist.ac.kr.
Abstract:
Herein, we described a microfluidic device that enabled the measurement of magnetic susceptibility of a subtle paramagnetic solution that could not be determined by conventional magnetic susceptibility measurement methods such as a superconducting quantum interference device (SQUID). We measured the diamagnetic repelling velocity of polystyrene microparticles suspended in a weak paramagnetic solution including 50-150 mM of gadolinium-diethylenetriamine penta-acetic acid (GD-DTPA) and superparamagnetic iron oxide nanoparticles (SPION) (10 nm in diameter) dispersed in distilled water at various concentrations. The measured diamagnetic repelling velocities correlated with our prediction and also with the magnetic susceptibility of the SPION solution measured by a SQUID magnetometer. Via this approach, we could determine the magnetic susceptibility of the subtle paramagnetic solution of GD-DTPA that could not be measured via the conventional method. This study provides us with the new capability of analyzing weakly paramagnetic solutions such as paramagnetic components or metal contaminants present in environmental liquid samples at low concentrations.
More Related Videos
13:28Simple and Effective Administration and Visualization of Microparticles in the Circulatory System of Small Fishes Using Kidney Injection
Published on: June 17, 2018
13:57Preparation and Friction Force Microscopy Measurements of Immiscible, Opposing Polymer Brushes
Published on: December 24, 2014
Related Concept Videos
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
Magnetic Susceptibility and Permeability
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...
Diamagnetism
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....
Diamagnetic Shielding of Nuclei: Local Diamagnetic Current
Paramagnetism
Polymers