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Magnetic relaxation switching (MRSw) assays that employ target-induced aggregation (or disaggregation) of magnetic nanoparticles (MNPs) can be used to detect a wide range of biomolecules. The precise working mechanisms, however, remain poorly understood, often leading to confounding interpretation. We herein present a systematic and comprehensive characterization of MRSw sensing. By using different types of MNPs with varying physical properties, we analyzed the nature and transverse relaxation modes for MRSw detection. The study found that clustered MNPs are universally in a diffusion-limited fractal state (dimension of ~2.4). Importantly, a new model for transverse relaxation was constructed that accurately recapitulates observed MRSw phenomena and predicts the MRSw detection sensitivities and dynamic ranges.
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http://dx.doi.org/10.1021/nn301615b | DOI Listing |
Inorg Chem
September 2025
Department of Chemistry, Panskura Banamali College, Panskura RS, Purba Medinipur, WB 721152, India.
We report the synthesis and characterization of a new Schiff base ligand (HL), derived from 2-picolylamine and 2-hydroxy-3-methoxy-5-methylbenzaldehyde. Its reaction with Ni(NO)·6HO and Ln(NO)·HO (Ln = Gd, Tb, Dy) in the presence of triethylamine affords a carbonato-bridged family of heterobimetallic NiLn complexes: [NiLn(L)(L')(μ-CO)(NO)]·MeOH·HO (). During the complexation reaction, ligand HL undergoes an oxidation, followed by C-C coupling to generate a secondary ligand (HL').
View Article and Find Full Text PDFTop Magn Reson Imaging
October 2025
BIOSPACE LAB, Nesles-la-Vallée, France.
Aims: Cardiac tumors are aggressive and asymptomatic in early stages, causing late diagnosis and locoregional metastasis. Currently, the standard of care uses gadolinium-based contrast agents for MRI, and the associated hypersensitivity reactions are a significant concern, such as gadolinium deposition disease. In addition, the proximity of cardiac lesions closer to vital structures complicates surgical interventions.
View Article and Find Full Text PDFMagn Reson Chem
September 2025
Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan.
We reveal contrasting behaviors in molecular motion between the two materials, including the identification of resonance-enhanced dynamic features in elastomers. We present a depth-resolved analysis of molecular dynamics in semicrystalline polytetrafluoroethylene (PTFE) and fully amorphous fluorinated elastomer (SIFEL) films using static-gradient solid-state F NMR imaging. By measuring spin-lattice relaxation rates ( ) at multiple frequencies and evaluating the corresponding spectral density functions, we reveal distinct dynamic behaviors between the two materials.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
Masaryk University, Faculty of Science, Department of Chemistry, Kotlářská 2, Brno, 611 37, Czech Republic.
Structural and magnetic properties of ultra-small tetrahedron-shaped iron oxide nanoparticles were investigated using density functional theory. Tetrahedral and truncated tetrahedral models were considered in both non-functionalized form and with surfaces passivated by pseudo-hydrogen atoms. The focus on these two morphologies reflects their experimental relevance at this size scale and the feasibility of performing fully relaxed, atomistically resolved first-principles simulations.
View Article and Find Full Text PDFMagn Reson Med
September 2025
Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Purpose: Gadoxetic acid-enhanced hepatobiliary phase T-weighted (Tw) MRI is effective for the detection of focal liver lesions but lacks sufficient T contrast to distinguish benign from malignant lesions. Although the addition of T, diffusion, and dynamic contrast-enhanced Tw imaging improves lesion characterization, these methods often do not provide adequate spatial resolution to identify subcentimeter lesions. This work proposes a high-resolution, volumetric, free-breathing liver MRI method that produces colocalized fat-suppressed, variable Tw images from a single acquisition, thereby improving both lesion detection and characterization.
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