Related Experiment Video
Updated: Jun 7, 2026
10:23
Synthesis of Cationized Magnetoferritin for Ultra-fast Magnetization of Cells
Published on: December 13, 2016
Size-dependent properties of magnetoferritin
M J Martínez-Pérez1, R de Miguel, C Carbonera
1Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Zaragoza, Spain.
Nanotechnology
|October 27, 2010
Summary
This study synthesized maghemite nanoparticles within apoferritin, revealing disordered magnetic structures and significantly enhanced magnetic anisotropy in these novel magnetoferritin cores.
Area of Science:
- Nanotechnology
- Biomaterials Science
- Magnetism
Background:
- Apoferritin serves as a biological template for synthesizing inorganic nanoparticles.
- Understanding the structure-property relationships of nanoparticles within biological scaffolds is crucial.
Purpose of the Study:
- To synthesize and characterize maghemite nanoparticles within apoferritin.
- To investigate the structural, molecular, and magnetic properties of these magnetoferritin cores.
- To determine the size-dependent magnetic anisotropy.
Main Methods:
- Synthesis of maghemite nanoparticles (1.6-6 nm) inside apoferritin.
- Structural characterization using Transmission Electron Microscopy (TEM) and X-ray diffraction.
- Molecular structure investigation via Atomic Force Microscopy (AFM).
- Magnetic property analysis using AC susceptibility, DC magnetization, and Mössbauer spectroscopy.
Main Results:
- Synthesized maghemite nanoparticles exhibit low crystalline order and reduced magnetic moments.
- Apoferritin shell shows a slight decrease in diameter, indicating conformational changes.
- Magnetoferritin cores display a highly disordered magnetic structure.
- Magnetic anisotropy constant (K) is significantly enhanced and size-dependent, increasing with decreasing nanoparticle size.
Conclusions:
- The synthesis of maghemite nanoparticles within apoferritin results in unique magnetoferritin cores with disordered magnetic structures.
- Enhanced magnetic anisotropy is attributed to low-symmetry sites at particle surfaces and domain interfaces.
- These findings highlight the potential of bio-templated synthesis for creating novel magnetic nanomaterials.
Related Concept Videos
01:31Ferromagnetism
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...
03:02Colors and Magnetism
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 eye.
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 eye.
01:31Magnetic 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...
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...
01:30Paramagnetism
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...
01:18Other Unique Bacteria
Magnetic bacteria exhibit a directed movement called magnetotaxis, driven by structures called magnetosomes. These magnetosomes consist of chains of magnetic particles made of either magnetite (Fe₃O₄) or greigite (Fe₃S₄) and are organized in a linear conformation by a protein scaffold within invaginations of the cell membrane. The bacteria align along the north–south magnetic field lines, much like a compass needle. They are typically microaerophilic or anaerobic and are commonly found near the...
01:23Magnetic Moment of an Electron
Electrons revolving around a nucleus are analogous to a circular current carrying loop. This current produces a magnetic dipole moment proportional to the electron's orbital angular momentum. Since the orbital angular momentum is quantized in terms of the reduced Planck's constant, the dipole moment is quantized in the Bohr Magneton. The value of the Bohr magneton is 9.27 x 10-24 Am2. Electrons also have an intrinsic spin angular momentum, and the associated spin magnetic moment is...