Biocompatible Iron Oxide Nanoparticles Display Antiviral Activity Against Two Different Respiratory Viruses in Mice.

Background: Severe Acute Respiratory syndrome coronavirus 2 (SARS-CoV-2) and Influenza A viruses (IAVs) are among the most important causes of viral respiratory tract infections, causing similar symptoms. IAV and SARS-CoV-2 infections can provoke mild symptoms like fever, cough, sore throat, loss of taste or smell, or they may cause more severe consequences leading to pneumonia, acute respiratory distress syndrome or even death. While treatments for IAV and SARS-CoV-2 infection are available, IAV antivirals often target viral proteins facilitating the emergence of drug-resistant viral variants.

Correction: Beyond Newton's law of cooling in evaluating magnetic hyperthermia performance: a device-independent procedure.

[This corrects the article DOI: 10.1039/D4NA00383G.].

Hybrid hydrogels support neural cell culture development under magnetic actuation at high frequency.

The combination of hydrogels and magnetic nanoparticles, scarcely explored to date, offers a wide range of possibilities for innovative therapies. Herein, we have designed hybrid 3D matrices integrating natural polymers, such as collagen, chitosan (CHI) and hyaluronic acid (HA), to provide soft and flexible 3D networks mimicking the extracellular matrix of natural tissues, and iron oxide nanoparticles (IONPs) that deliver localized heat when exposed to an alternating magnetic field (AMF). First, colloidally stable nanoparticles with a hydrodynamic radius of ∼20 nm were synthesized and coated with either CHI (NPCHI) or HA (NPHA).

Inductive Heating Enhances Ripening in the Aqueous Synthesis of Magnetic Nanoparticles.

The search for competitive processes and products using environmentally friendly chemistry is, nowadays, one of the greatest challenges in materials science. In this work, we explore the influence of magnetic inductive heating on the synthesis of magnetic iron oxide nanoparticles in water, either by the coprecipitation of iron(II) and iron(III) salts or by the oxidative precipitation of an iron(II) salt. In the first case, the way the heat is transmitted to the system influences mainly the nanoparticle growth that is thermally activated reaching nanoparticles up to 16 nm.

Iron oxide and iron oxyhydroxide nanoparticles impair SARS-CoV-2 infection of cultured cells.

Background: Coronaviruses usually cause mild respiratory disease in humans but as seen recently, some human coronaviruses can cause more severe diseases, such as the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the global spread of which has resulted in the ongoing coronavirus pandemic.

Results: In this study we analyzed the potential of using iron oxide nanoparticles (IONPs) coated with biocompatible molecules like dimercaptosuccinic acid (DMSA), 3-aminopropyl triethoxysilane (APS) or carboxydextran (FeraSpin™ R), as well as iron oxyhydroxide nanoparticles (IOHNPs) coated with sucrose (Venofer), or iron salts (ferric ammonium citrate -FAC), to treat and/or prevent SARS-CoV-2 infection. At non-cytotoxic doses, IONPs and IOHNPs impaired virus replication and transcription, and the production of infectious viruses in vitro, either when the cells were treated prior to or after infection, although with different efficiencies.

Unravelling an amine-regulated crystallization crossover to prove single/multicore effects on the biomedical and environmental catalytic activity of magnetic iron oxide colloids.

Elucidation of reaction mechanisms in forming nanostructures is relevant to obtain robust and affordable protocols that can lead to materials with enhanced properties and good reproducibility. Here, the formation of magnetic iron oxide monocrystalline nanoflowers in polyol solvents using N-methyldiethanolamine (NMDEA) as co-solvent has been shown to occur through a non-classical crystallization pathway. This pathway involves intermediate mesocrystals that, in addition, can be transformed into large single colloidal nanocrystals.

Reproducibility and Scalability of Magnetic Nanoheater Synthesis.

The application of magnetic nanoparticles requires large amounts of materials of reproducible quality. This work explores the scaled-up synthesis of multi-core iron oxide nanoparticles through the use of thermal decomposition in organic media and kilograms of reagents. To this end, we check the effect of extending the high temperature step from minutes to hours.

Selective Magnetic Nanoheating: Combining Iron Oxide Nanoparticles for Multi-Hot-Spot Induction and Sequential Regulation.

The contactless heating capacity of magnetic nanoparticles (MNPs) has been exploited in fields such as hyperthermia cancer therapy, catalysis, and enzymatic thermal regulation. Herein, we propose an advanced technology to generate multiple local temperatures in a single-pot reactor by exploiting the unique nanoheating features of iron oxide MNPs exposed to alternating magnetic fields (AMFs). The heating power of the MNPs depends on their magnetic features but also on the intensity and frequency conditions of the AMF.

Engineering Iron Oxide Nanocatalysts by a Microwave-Assisted Polyol Method for the Magnetically Induced Degradation of Organic Pollutants.

Advanced oxidation processes constitute a promising alternative for the treatment of wastewater containing organic pollutants. Still, the lack of cost-effective processes has hampered the widespread use of these methodologies. Iron oxide magnetic nanoparticles stand as a great alternative since they can be engineered by different reproducible and scalable methods.

Whither Magnetic Hyperthermia? A Tentative Roadmap.

The scientific community has made great efforts in advancing magnetic hyperthermia for the last two decades after going through a sizeable research lapse from its establishment. All the progress made in various topics ranging from nanoparticle synthesis to biocompatibilization and in vivo testing have been seeking to push the forefront towards some new clinical trials. As many, they did not go at the expected pace.

Cu-Doped Extremely Small Iron Oxide Nanoparticles with Large Longitudinal Relaxivity: One-Pot Synthesis and in Vivo Targeted Molecular Imaging.

Synthesizing iron oxide nanoparticles for positive contrast in magnetic resonance imaging is the most promising approach to bring this nanomaterial back to the clinical field. The success of this approach depends on several aspects: the longitudinal relaxivity values, the complexity of the synthetic protocol, and the reproducibility of the synthesis. Here, we show our latest results on this goal.

Design strategies for shape-controlled magnetic iron oxide nanoparticles.

Ferrimagnetic iron oxide nanoparticles (magnetite or maghemite) have been the subject of an intense research, not only for fundamental research but also for their potentiality in a widespread number of practical applications. Most of these studies were focused on nanoparticles with spherical morphology but recently there is an emerging interest on anisometric nanoparticles. This review is focused on the synthesis routes for the production of uniform anisometric magnetite/maghemite nanoparticles with different morphologies like cubes, rods, disks, flowers and many others, such as hollow spheres, worms, stars or tetrapods.

Improving the reliability of the iron concentration quantification for iron oxide nanoparticle suspensions: a two-institutions study.

Most iron oxide nanoparticles applications, and in special biomedical applications, require the accurate determination of iron content as the determination of particle properties from measurements in dispersions is strongly dependent on it. Inductively coupled plasma (ICP) and spectrophotometry are two typical worldwide used analytical methods for iron concentration determination. In both techniques, precise determination of iron is not straightforward and nanoparticle digestion and dilution procedures are needed prior to analysis.

Effect of the Sodium Polyacrylate on the Magnetite Nanoparticles Produced by Green Chemistry Routes: Applicability in Forward Osmosis.

Aqueous dispersions of magnetic nanocomposites have been proposed as draw electrolytes in forward osmosis. One possible approach for the production of nanocomposites based on magnetite nanoparticles and sodium polyacrylate is the synthesis of the magnetic iron oxide by coprecipitation or oxidative precipitation in the presence of an excess of the polymer. In this work, we explored the effect of the polymer proportion on the nanomaterials produced by these procedures.

Formation Mechanism of Maghemite Nanoflowers Synthesized by a Polyol-Mediated Process.

Magnetic nanoparticles are being developed as structural and functional materials for use in diverse areas, including biomedical applications. Here, we report the synthesis of maghemite (γ-FeO) nanoparticles with distinct morphologies: single-core and multicore, including hollow spheres and nanoflowers, prepared by the polyol process. We have used sodium acetate to control the nucleation and assembly process to obtain the different particle morphologies.

SAXS analysis of single- and multi-core iron oxide magnetic nanoparticles.

This article reports on the characterization of four superparamagnetic iron oxide nanoparticles stabilized with dimercaptosuccinic acid, which are suitable candidates for reference materials for magnetic properties. Particles p and p are single-core particles, while p and p are multi-core particles. Small-angle X-ray scattering analysis reveals a lognormal type of size distribution for the iron oxide cores of the particles.

Degradation of magnetic nanoparticles mimicking lysosomal conditions followed by AC susceptibility.

Background: A deeper knowledge on the effects of the degradation of magnetic nanoparticles on their magnetic properties is required to develop tools for the identification and quantification of magnetic nanoparticles in biological media by magnetic means.

Methods: Citric acid and phosphonoacetic acid-coated magnetic nanoparticles have been degraded in a medium that mimics lysosomal conditions. Magnetic measurements and transmission electron microscopy have been used to follow up the degradation process.

Bismuth labeling for the CT assessment of local administration of magnetic nanoparticles.

Many therapeutic applications of magnetic nanoparticles involve the local administration of nanometric iron oxide based materials as seeds for magnetothermia or drug carriers. A simple and widespread way of controlling the process using x-ray computed tomography (CT) scanners is desirable. The combination of iron and bismuth in one entity will increase the atenuation of x-rays, offering such a possibility.

Synthesis methods to prepare single- and multi-core iron oxide nanoparticles for biomedical applications.

We review current synthetic routes to magnetic iron oxide nanoparticles for biomedical applications. We classify the different approaches used depending on their ability to generate magnetic particles that are either single-core (containing only one magnetic core, i.e.

Effects of phase transfer ligands on monodisperse iron oxide magnetic nanoparticles.

Oleic acid coated iron oxide nanoparticles synthesized by thermal decomposition in organic medium are highly monodisperse but at the same time are unsuitable for biological applications. Ligand-exchange reactions are useful to make their surface hydrophilic. However, these could alter some structural and magnetic properties of the modified particles.

Structural determination of Bi-doped magnetite multifunctional nanoparticles for contrast imaging.

To determine with precision how Bi atoms are distributed in Bi-doped iron oxide nanoparticles their structural characterization has been carried out by X-ray absorption spectroscopy (XAS) recorded at the K edge of Fe and at the L3 edge of Bi. The inorganic nanoparticles are nominally hybrid structures integrating an iron oxide core and a bismuth oxide shell. Fe K-edge XAS indicates the formation of a structurally ordered, non-stoichiometric magnetite (Fe3-δO4) phase for all the nanoparticles.

The Viedma deracemization of racemic conglomerate mixtures as a paradigm of spontaneous mirror symmetry breaking in aggregation and polymerization.

Simulations of a chemical kinetics model, based on the free-energy relationships of classical primary nucleation theory, show that the deracemization phenomenon in systems of achiral or fast racemizing compounds yielding enantiopure crystals as the more stable solid phase is a true spontaneous mirror symmetry breaking process (SMSB). That is, the achievement of a stationary chiral state is more stable than the racemic one. The model translates the free-energy relationships determined by the existence of a critical size cluster to a chemical kinetics model, in which the consideration of forward and backward reaction rate constants avoids the misuse of network parameters that violate thermodynamic constraints (microreversibility principle), which would lead to apparent in silico SMSB.