Related Experiment Video
Updated: Jul 26, 2025
07:24
Paramagnetic Relaxation Enhancement for Detecting and Characterizing Self-Associations of Intrinsically Disordered Proteins
Published on: September 23, 2021
1.8K
Comment on "Structure-Correlated Magnetic Resonance Transverse Relaxivity Enhancement in Superparamagnetic Ensembles
Langmuir : the ACS Journal of Surfaces and Colloids
|June 15, 2023
Summary
This comment questions the proposed relaxation model for superparamagnetic nanoparticle clusters. The authors express reservations about its adequacy in explaining proton nuclear magnetic resonance transverse relaxation.
Area of Science:
- Condensed matter physics
- Materials science
- Biophysics
Context:
- Superparamagnetic nanoparticle clusters are crucial in various applications, including magnetic resonance imaging (MRI) contrast agents.
- Proton nuclear magnetic resonance (NMR) transverse relaxation is a key parameter influenced by these nanoparticles.
- Konwar et al. recently proposed a new model relating nanoparticle cluster structure to NMR relaxation.
Purpose:
- To critically evaluate the proposed relaxation model by Konwar et al.
- To express reservations regarding the adequacy and applicability of the new model.
- To stimulate further discussion and refinement of models describing nanoparticle-water interactions.
Summary:
- This comment addresses the recent work by Konwar et al. on superparamagnetic nanoparticle clusters and their effect on proton NMR transverse relaxation.
- The authors raise concerns about the validity and limitations of the newly proposed relaxation model.
- Specific reservations are detailed concerning the model's assumptions and predictive power.
Impact:
- Highlights potential shortcomings in current theoretical frameworks for superparamagnetic nanoparticle systems.
- Encourages rigorous validation of new models before widespread adoption in scientific literature.
- Contributes to the ongoing scientific discourse on nanoparticle-based contrast agents and their characterization.
Related Concept Videos
01:08NMR Spectroscopy: Spin–Spin Coupling
1.5K
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...
1.5K
01:23Atomic Nuclei: Nuclear Relaxation Processes
685
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
685
01:05Atomic Nuclei: Magnetic Resonance
694
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
694
01:182D NMR: Overview of Heteronuclear Correlation Techniques
234
Heteronuclear correlation spectroscopy is an analytical technique that investigates the coupling between different types of nuclei, often a proton and an X-nucleus, such as carbon-13 or nitrogen-15. This method is commonly used in nuclear magnetic resonance (NMR) spectroscopy to gain insights into complex chemical compounds' structural and compositional aspects. A typical heteronuclear correlation spectrum displays X-nucleus chemical shifts on one axis and a proton spectrum on the other...
234
01:162D NMR: Overview of Homonuclear Correlation Techniques
245
Homonuclear correlation spectroscopy (COSY) is a powerful technique used in Nuclear Magnetic Resonance (NMR) spectroscopy to study the correlations between nuclei of the same type within a molecule. It provides information about scalar couplings between adjacent nuclei, which helps determine connectivity and structural information. There are several COSY variants, each with its unique strengths and experimental parameters.
COSY90 is the standard two-dimensional (2D) COSY experiment that...
COSY90 is the standard two-dimensional (2D) COSY experiment that...
245
01:31Magnetic Susceptibility and Permeability
1.2K
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...
1.2K