Related Experiment Video
Updated: Oct 7, 2025
10:45
Stable Aqueous Suspensions of Manganese Ferrite Clusters with Tunable Nanoscale Dimension and Composition
Published on: February 5, 2022
4.4K
Reduced Magnetic Coupling in Ultrasmall Iron Oxide T1 MRI Contrast Agents
Fabian H L Starsich, Christian Eberhardt1, Kerda Keevend2
1Institute of Diagnostic and Interventional Radiology, University Hospital Zürich, Rämistrasse 100, CH-8091 Zürich, Switzerland.
ACS Applied Bio Materials
|January 8, 2022
Summary
Ultrasmall iron oxide nanocrystals offer a promising, cytocompatible alternative to gadolinium-based T1 magnetic resonance imaging (MRI) contrast agents. These novel agents show comparable relaxivity and no cytotoxicity, addressing safety concerns associated with gadolinium.
Area of Science:
- Nanotechnology
- Biomedical Imaging
- Materials Science
Background:
- Contrast-enhanced magnetic resonance imaging (MRI) is crucial for diagnosing soft tissue pathologies.
- T1-weighted MRI offers advantages in image analysis and acquisition speed over T2-weighted imaging.
- Existing gadolinium (Gd3+)-based T1 contrast agents pose risks, including nephrogenic systemic fibrosis.
Purpose of the Study:
- To investigate ultrasmall iron oxide nanocrystals (IONCs) as T1 MRI contrast agents.
- To evaluate the structure-function relationships and cytocompatibility of flame-synthesized IONCs.
- To explore SiO2-templated IONCs for tunable contrast enhancement.
Main Methods:
- Scalable flame aerosol technology for IONC synthesis.
- In vitro cytocompatibility testing against PC3, HepG2, THP-1, and red blood cells.
- Assessment of T1 relaxivity and contrast enhancement properties.
Main Results:
- Optimized IONCs demonstrated comparable T1 relaxivity to commercial Gd-based agents.
- No apparent cytotoxicity was observed at clinically relevant concentrations.
- SiO2 spacing allowed fine-tuning of contrast enhancement by controlling IONC magnetic size and coupling.
Conclusions:
- Ultrasmall IONCs are a promising, cytocompatible alternative to Gd-based T1 MRI contrast agents.
- Flame aerosol synthesis provides a scalable route for producing these advanced nanomaterials.
- IONC-based agents offer tunable contrast enhancement with improved safety profiles.
More Related Videos
Related Concept Videos
01:24Magnetic Resonance Imaging
7.9K
Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device in clinical use by the early 1980s. The early MRI...
7.9K
01:31Ferromagnetism
2.5K
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...
2.5K
03:02Colors and Magnetism
12.5K
Color in Coordination Complexes
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...
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...
12.5K
01:08NMR Spectroscopy: Spin–Spin Coupling
1.7K
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved...
1.7K
01:31Magnetic Susceptibility and Permeability
1.5K
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...
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...
1.5K
01:30Paramagnetism
2.6K
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