Front Neurosci
March 2025
[This corrects the article DOI: 10.3389/fnins.2025.
View Article and Find Full Text PDFEven though it is not well characterized how much humans can sense the geomagnetic field (GMF), numerous magnetosensitive animals can detect GMF broadly as a sensory cue, when a spatial decision-making is needed for orientation or migration. In an article of recent series of studies, we showed that the empirical probabilities of stone selections in Go game were significantly different from the theoretical probability. In this study, we assessed the implication of the GMF in modulating subconscious non-spatial decision-making in human subjects and the underlying mechanism with exploiting the zero-sum binary stone selection of Go game as a proof-of-principle.
View Article and Find Full Text PDFMany studies have been conducted on the use of ultra-small iron oxide nanoparticles (USIONs) (d < 3 nm) as potential positive magnetic resonance imaging (MRI)-contrast agents (CAs); however, there is dearth of research on clustered USIONs. In this study, nearly monodispersed clustered USIONs were synthesized using a simple two-step one-pot polyol method. First, USIONs (d = 2.
View Article and Find Full Text PDFOwing to their theranostic properties, cerium oxide (CeO) nanoparticles have attracted considerable attention for their key applications in nanomedicine. In this study, ultrasmall CeO nanoparticles (particle diameter = 1-3 nm) as X-ray contrast agents with an antioxidant effect were investigated for the first time. The nanoparticles were coated with hydrophilic and biocompatible poly(acrylic acid) (PAA) and poly(acrylic acid--maleic acid) (PAAMA) to ensure satisfactory colloidal stability in aqueous media and low cellular toxicity.
View Article and Find Full Text PDFMagnetite nanoparticles (FeO NPs) have been intensively investigated because of their potential biomedical applications due to their high saturation magnetization. In this study, core-shell FeO@C NPs (core = FeO NPs and shell = amorphous carbons, d = 35.1 nm) were synthesized in an aqueous solution.
View Article and Find Full Text PDFHydrophilic and biocompatible PAA-coated ultrasmall GdO nanoparticles (d = 1.7 nm) were synthesized and conjugated with tumor-targeting ligands, i.e.
View Article and Find Full Text PDFWater proton spin relaxivities, colloidal stability, and biocompatibility of nanoparticle magnetic resonance imaging (MRI) contrast agents depend on surface-coating ligands. In this study, hydrophilic and biocompatible polyethylenimines (PEIs) of different sizes (M = 1200 and 60,000 amu) were used as surface-coating ligands for ultrasmall holmium oxide (HoO) nanoparticles. The synthesized PEI1200- and PEI60000-coated ultrasmall HoO nanoparticles, with an average particle diameter of 2.
View Article and Find Full Text PDFOwing to a higher demand for glucosamine (GlcN) in metabolic processes in tumor cells than in normal cells (i.e., GlcN effects), tumor imaging in magnetic resonance imaging (MRI) can be highly improved using GlcN-conjugated MRI contrast agents.
View Article and Find Full Text PDFPolyacrylic acid (PAA)-coated lanthanide oxide (LnO) nanoparticles (NPs) (Ln = Tb and Ho) with high colloidal stability and good biocompatibility were synthesized, characterized, and investigated as a new class of negative (T) magnetic resonance imaging (MRI) contrast agents at high MR fields. Their r values were appreciable at a 3.0 T MR field and higher at a 9.
View Article and Find Full Text PDFIn this study, hydrophilic and biocompatible chitosan oligosaccharide lactate (COL)-coated ultra-small gadolinium oxide nanoparticles (NPs) were synthesized through a one-pot polyol method and characterized by various experimental techniques. The cellular cytotoxicity assay indicated that the COL-coated gadolinium oxide NPs were non-toxic up to 500 M Gd. In addition, their water proton spin relaxivities (i.
View Article and Find Full Text PDFThe water proton spin relaxivity, colloidal stability, and biocompatibility of nanoparticle-based magnetic resonance imaging (MRI) contrast agents depend on the surface-coating ligands. Here, poly(acrylic acid-co-maleic acid) (PAAMA) (M = ~3000 amu) is explored as a surface-coating ligand of ultrasmall gadolinium oxide (GdO) nanoparticles. Owing to the numerous carboxylic groups in PAAMA, which allow its strong conjugation with the nanoparticle surfaces and the attraction of abundant water molecules to the nanoparticles, the synthesized PAAMA-coated ultrasmall GdO nanoparticles (d = 1.
View Article and Find Full Text PDFPharmaceuticals (Basel)
October 2020
Nanoparticles are considered potential candidates for a new class of magnetic resonance imaging (MRI) contrast agents. Negative MRI contrast agents require high magnetic moments. However, if nanoparticles can exclusively induce transverse water proton spin relaxation with negligible induction of longitudinal water proton spin relaxation, they may provide negative contrast MR images despite having low magnetic moments, thus acting as an efficient T MRI contrast agent.
View Article and Find Full Text PDFThe study of ultra-small paramagnetic gadolinium oxide (GdO) nanoparticles (NPs) as in vivo positive (T) magnetic resonance imaging (MRI) contrast agents is one of the most attractive fields in nanomedicine. The performance of the GdO NP imaging agents depends on the surface-coating materials. In this study, poly(methyl vinyl ether-alt-maleic acid) (PMVEMA) was used as a surface-coating polymer.
View Article and Find Full Text PDFJ Nanosci Nanotechnol
August 2020
Ultrasmall Bi₂O₃ nanoparticles ( = 1.5 nm) coated with biocompatible and hydrophilic D-glucuronic acid were prepared for the first time through a simple one-step polyol process and their potential as CT contrast agents were investigated by measuring their X-ray attenuation properties. Their observed X-ray attenuation power was stronger than that of a commercial iodine CT contrast agent at the same atomic concentration, as consistent with the magnitudes of atomic X-ray attenuation coefficients (i.
View Article and Find Full Text PDFGadolinium neutron capture therapy (GdNCT) is considered as a new promising cancer therapeutic technique. Nevertheless, limited GdNCT applications have been reported so far. In this study, surface-modified ultrasmall gadolinium oxide nanoparticles (UGNPs) with cancer-targeting ability ( = 1.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2020
Certain long-distance migratory animals, such as salmon and sea turtles, are thought to imprint on the magnetic field of their natal area and to use this information to help them return as adults. Despite a growing body of indirect support for such imprinting, direct experimental evidence thereof remains elusive. Here, using the fruit fly as a magnetoreceptive model organism, we demonstrate that exposure to a specific geographic magnetic field during a critical period of early development affected responses to a matching magnetic field gradient later in life.
View Article and Find Full Text PDFThe Earth's geomagnetic field (GMF) is known to influence magnetoreceptive creatures, from bacteria to mammals as a sensory cue or a physiological modulator, despite it is largely thought that humans cannot sense the GMF. Here, we show that humans sense the GMF to orient their direction toward food in a self-rotatory chair experiment. Starved men, but not women, significantly oriented toward the ambient/modulated magnetic north or east, directions which had been previously food-associated, without any other helpful cues, including sight and sound.
View Article and Find Full Text PDFJ Nanosci Nanotechnol
September 2018
D-glucuronic acid-coated ultrasmall chromium oxide (Cr2O3) nanoparticles were synthesized by a one-pot polyol method and their relaxometric and optical properties were investigated. The as-synthesized D-glucuronic acid-coated nanoparticles were amorphous owing to ultrasmall particle diameters (davg = 2.0 nm), whereas orthorhombic Cr2O3 nanoparticles with two size groups (davg = 3.
View Article and Find Full Text PDFJ Nanosci Nanotechnol
April 2017
Mixed Zn(II)/Gd(III) oxide nanoparticles (~8 mole%Zn) with d(avg) of 2.1 nm were synthesized. The D-glucuronic acid coated Zn(II)/Gd(III) oxide nanoparticles showed a longitudinal water proton relaxivity (r₁) of 12.
View Article and Find Full Text PDFMonodisperse and ultrasmall gadolinium oxide (GdO) nanoparticle colloids ( = 1.5 nm) (nanoparticle colloid = nanoparticle coated with hydrophilic ligand) were synthesized and their performance as a multifunctional tumor theragnostic agent was investigated. The aqueous ultrasmall nanoparticle colloidal suspension was stable and non-toxic owing to hydrophilic polyacrylic acid (PAA) coating that was partly conjugated with rhodamine B (Rho) for an additional functionalization (mole ratio of PAA : Rho = 5 : 1).
View Article and Find Full Text PDFFor use as positive ( ) magnetic resonance imaging contrast agents (MRI-CAs), gadolinium oxide (GdO) nanoparticle colloids ( nanoparticles coated with hydrophilic ligands) should be stable, non-toxic, and ultrasmall in particle diameter for renal excretion. In addition, they should have a high longitudinal water proton relaxivity ( ) and / ratio that is close to one ( = transverse water proton relaxivity) for high-performance. In this study, we report ultrasmall GdO nanoparticle colloids [coating material = polyacrylic acid, = ∼5100 Da] satisfying these conditions.
View Article and Find Full Text PDFFront Hum Neurosci
September 2017
Throughout the long history of various therapeutic trials of transcranial magnetic stimulation (TMS), some TMS protocols have been reported to be clearly effective in the treatment of neurodegenerative diseases. Despite promising results from repetitive TMS (rTMS) using low frequency electromagnetic fields (EMFs) for neurodegenerative diseases, the low reproducibility has hampered the clinical applications of rTMS. Here, based on the notion of radical pair mechanism explaining magnetoreception in living organisms, we propose a new perspective that rTMS with controlled geomagnetic field (rTMS-GMF) can be an efficient and reproducible therapeutic approach for neurodegenerative diseases.
View Article and Find Full Text PDFWater-soluble and biocompatible D-glucuronic acid coated NaWO and BaCO nanoparticles were synthesized for the first time to be used as x-ray computed tomography (CT) contrast agents. Their average particle diameters were 3.2 ± 0.
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