Clustered ultra-small iron oxide nanoparticles as potential T/Tdual-modal magnetic resonance imaging contrast agents and application to tumor model.

Many 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.

Ultrasmall cerium oxide nanoparticles as highly sensitive X-ray contrast agents and their antioxidant effect.

Owing 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.

Core-Shell FeO@C Nanoparticles as Highly Effective T Magnetic Resonance Imaging Contrast Agents: In Vitro and In Vivo Studies.

Magnetite 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.

Mono and Multiple Tumor-Targeting Ligand-Coated Ultrasmall Gadolinium Oxide Nanoparticles: Enhanced Tumor Imaging and Blood Circulation.

Hydrophilic and biocompatible PAA-coated ultrasmall GdO nanoparticles (d = 1.7 nm) were synthesized and conjugated with tumor-targeting ligands, i.e.

Polyethylenimine-Coated Ultrasmall Holmium Oxide Nanoparticles: Synthesis, Characterization, Cytotoxicities, and Water Proton Spin Relaxivities.

Water 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.

Enhanced Tumor Imaging Using Glucosamine-Conjugated Polyacrylic Acid-Coated Ultrasmall Gadolinium Oxide Nanoparticles in Magnetic Resonance Imaging.

Owing 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.

Synthesis, Characterizations, and 9.4 Tesla T MR Images of Polyacrylic Acid-Coated Terbium(III) and Holmium(III) Oxide Nanoparticles.

Polyacrylic 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.

Chitosan Oligosaccharide Lactate-Coated Ultrasmall Gadolinium Oxide Nanoparticles: Synthesis, Cytotoxicity, and Relaxometric Properties.

In 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.

Hydrophilic Biocompatible Poly(Acrylic Acid-co-Maleic Acid) Polymer as a Surface-Coating Ligand of Ultrasmall GdO Nanoparticles to Obtain a High r Value and T MR Images.

The 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.

New Class of Efficient T Magnetic Resonance Imaging Contrast Agent: Carbon-Coated Paramagnetic Dysprosium Oxide Nanoparticles.

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.

In Vivo Positive Magnetic Resonance Imaging Applications of Poly(methyl vinyl ether-alt-maleic acid)-coated Ultra-small Paramagnetic Gadolinium Oxide Nanoparticles.

The 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.

D-Glucuronic Acid-Coated Ultrasmall Bi₂O₃ Nanoparticles for CT Imaging.

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.

neutron capture therapy of cancer using ultrasmall gadolinium oxide nanoparticles with cancer-targeting ability.

Gadolinium 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.

Behavioral evidence for geomagnetic imprinting and transgenerational inheritance in fruit flies.

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.

Correction: Blue light-dependent human magnetoreception in geomagnetic food orientation.

[This corrects the article DOI: 10.1371/journal.pone.

Blue light-dependent human magnetoreception in geomagnetic food orientation.

The 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.

Relaxometric, Optical and Cell Viability Properties of D-Glucuronic Acid Coated Cr₂O₃ Nanoparticles.

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.

Longitudinal Water Proton Relaxivity and In Vivo T₁ MR Images of Mixed Zn(II)/Gd(III) Oxide Nanoparticles.

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.

Magnetic resonance imaging, gadolinium neutron capture therapy, and tumor cell detection using ultrasmall GdO nanoparticles coated with polyacrylic acid-rhodamine B as a multifunctional tumor theragnostic agent.

Monodisperse 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).

Stable and non-toxic ultrasmall gadolinium oxide nanoparticle colloids (coating material = polyacrylic acid) as high-performance magnetic resonance imaging contrast agents.

For 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.

Potential Impact of Geomagnetic Field in Transcranial Magnetic Stimulation for the Treatment of Neurodegenerative Diseases.

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.

Synthesis of nanoparticle CT contrast agents: and studies.

Water-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.

Positive geotactic behaviors induced by geomagnetic field in Drosophila.

Background: Appropriate vertical movement is critical for the survival of flying animals. Although negative geotaxis (moving away from Earth) driven by gravity has been extensively studied, much less is understood concerning a static regulatory mechanism for inducing positive geotaxis (moving toward Earth).

Results: Using Drosophila melanogaster as a model organism, we showed that geomagnetic field (GMF) induces positive geotaxis and antagonizes negative gravitaxis.

Dual-mode T1 and T2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application.

A new type of dual-mode T1 and T2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd(3+) ((8)S7/2) plays an important role in T1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy(3+) ((6)H15/2) has the potential to be used in T2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy2O3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd(3+) and Dy(3+) and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T1 and T2 MRI contrast agent was investigated in vitro and in vivo.