On the Use of Laser Fragmentation for the Synthesis of Ligand-Free Ultra-Small Iron Nanoparticles in Various Liquid Environments

Traditionally, the synthesis of nanomaterials in the ultra-small size regime (1–3 nm diameter) has been linked with the employment of excessive amounts of hazardous chemicals, inevitably leading to significant environmentally detrimental effects. In the current work, we demonstrate the potential of laser fragmentation in liquids (LFL) to produce highly pure and stable iron ultra-small nanoparticles. This is carried out by reducing the size of carbonyl iron microparticles dispersed in various polar solvents (water, ethanol, ethylene glycol, polyethylene glycol 400) and liquid nitrogen. The explored method enables the fabrication of ligand-free iron oxide ultra-small nanoparticles with diameter in the 1–3 nm range, a tight size distribution, and excellent hydrodynamic stability (zeta potential > 50 mV). The generated particles can be found in different forms, including separated ultra-small NPs, ultra-small NPs forming agglomerates, and ultra-small NPs together with zero-valent iron, iron carbide, or iron oxide NPs embedded in matrices, depending on the employed solvent and their dipolar moment. The LFL technique, aside from avoiding chemical waste generation, does not require any additional chemical agent, other than the precursor microparticles immersed in the corresponding solvent. In contrast to their widely exploited chemically synthesized counterparts, the lack of additives and chemical residuals may be of fundamental interest in sectors requiring colloidal stability and the largest possible number of chemically active sites, making the presented pathway a promising alternative for the clean design of new-generation nanomaterials.

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MOF-Mediated Synthesis of Supported Fe-doped Pd Nanoparticles under Mild Conditions for Magnetically Recoverable Catalysis

10.26434/chemrxiv.12151809.v1 ◽

2020 ◽

Author(s):

Guillermo Minguez Espallargas ◽

Mohanad D. Darawsheh ◽

Dr. Mónica Giménez Marqués ◽

Marcelo E. Domine ◽

Pascual Oña-Burgos ◽

...

Keyword(s):

Iron Oxide ◽

Active Sites ◽

Pd Nanoparticles ◽

Reusable Catalyst ◽

Synthetic Approach ◽

Promising Alternative ◽

Mild Conditions ◽

Catalytic Materials ◽

In Situ Generation

MOF-driven synthesis is considered as a promising alternative for the development of new catalytic materials with well-designed active sites. This synthetic approach is used here to gradually transform a new bimetallic MOF, composed of Pd and Fe as metal components, via the in situ generation of aniline under mild conditions. This methodology results in a compositionally homogeneous nanocomposite formed by Fedoped Pd nanoparticles and these, in turn, supported on an iron oxide-doped carbon. The nanocomposite has been fully characterized by several techniques such as IR, Raman, TEM, XPS, XAS, among others. The performance of this nanocomposite as an heterogeneous catalyst for hydrogenation of nitroarenes and nitrobenzene coupling with benzaldehyde has been evaluated, proving it to be an efficient and reusable catalyst.

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MOF-Mediated Synthesis of Supported Fe-doped Pd Nanoparticles under Mild Conditions for Magnetically Recoverable Catalysis

10.26434/chemrxiv.12151809 ◽

2020 ◽

Author(s):

Guillermo Minguez Espallargas ◽

Mohanad D. Darawsheh ◽

Dr. Mónica Giménez Marqués ◽

Marcelo E. Domine ◽

Pascual Oña-Burgos ◽

...

Keyword(s):

Iron Oxide ◽

Active Sites ◽

Pd Nanoparticles ◽

Reusable Catalyst ◽

Synthetic Approach ◽

Promising Alternative ◽

Mild Conditions ◽

Catalytic Materials ◽

In Situ Generation

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Macrophage-Laden Gold Nanoflowers Embedded with Ultrasmall Iron Oxide Nanoparticles for Enhanced Dual-Mode CT/MR Imaging of Tumors

Pharmaceutics ◽

10.3390/pharmaceutics13070995 ◽

2021 ◽

Vol 13 (7) ◽

pp. 995

Author(s):

Yucheng Peng ◽

Xiaomeng Wang ◽

Yue Wang ◽

Yue Gao ◽

Rui Guo ◽

...

Keyword(s):

Iron Oxide ◽

Mr Imaging ◽

Iron Oxide Nanoparticles ◽

Colloidal Stability ◽

Pamam Dendrimer ◽

Great Promise ◽

Oxide Nanoparticles ◽

Dual Mode ◽

Gold Nanoflowers ◽

Average Size

The design of multimodal imaging nanoplatforms with improved tumor accumulation represents a major trend in the current development of precision nanomedicine. To this end, we report herein the preparation of macrophage (MA)-laden gold nanoflowers (NFs) embedded with ultrasmall iron oxide nanoparticles (USIO NPs) for enhanced dual-mode computed tomography (CT) and magnetic resonance (MR) imaging of tumors. In this work, generation 5 poly(amidoamine) (G5 PAMAM) dendrimer-stabilized gold (Au) NPs were conjugated with sodium citrate-stabilized USIO NPs to form hybrid seed particles for the subsequent growth of Au nanoflowers (NFs). Afterwards, the remaining terminal amines of dendrimers were acetylated to form the dendrimer-stabilized Fe3O4/Au NFs (for short, Fe3O4/Au DSNFs). The acquired Fe3O4/Au DSNFs possess an average size around 90 nm, display a high r1 relaxivity (1.22 mM−1 s−1), and exhibit good colloidal stability and cytocompatibility. The created hybrid DSNFs can be loaded within MAs without producing any toxicity to the cells. Through the mediation of MAs with a tumor homing and immune evasion property, the Fe3O4/Au DSNFs can be delivered to tumors more efficiently than those without MAs after intravenous injection, thus significantly improving the MR/CT imaging performance of tumors. The developed MA-mediated delivery system may hold great promise for enhanced tumor delivery of other contrast agents or nanomedicines for precision cancer nanomedicine applications.

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Influence of Phase Composition and Pretreatment on the Conversion of Iron Oxides into Iron Carbides in Syngas Atmospheres

Catalysts ◽

10.3390/catal11070773 ◽

2021 ◽

Vol 11 (7) ◽

pp. 773

Author(s):

Aleks Arinchtein ◽

Meng-Yang Ye ◽

Michael Geske ◽

Marvin Frisch ◽

Ralph Kraehnert

Keyword(s):

Phase Composition ◽

Iron Oxide ◽

Self Assembly ◽

Iron Carbide ◽

Active Phase ◽

Physicochemical Analysis ◽

Carbide Formation ◽

Iron Carbides ◽

Carbide Phases ◽

Higher Hydrocarbons

CO2 Fischer–Tropsch synthesis (CO2–FTS) is a promising technology enabling conversion of CO2 into valuable chemical feedstocks via hydrogenation. Iron–based CO2–FTS catalysts are known for their high activities and selectivities towards the formation of higher hydrocarbons. Importantly, iron carbides are the presumed active phase strongly associated with the formation of higher hydrocarbons. Yet, many factors such as reaction temperature, atmosphere, and pressure can lead to complex transformations between different oxide and/or carbide phases, which, in turn, alter selectivity. Thus, understanding the mechanism and kinetics of carbide formation remains challenging. We propose model–type iron oxide films of controlled nanostructure and phase composition as model materials to study carbide formation in syngas atmospheres. In the present work, different iron oxide precursor films with controlled phase composition (hematite, ferrihydrite, maghemite, maghemite/magnetite) and ordered mesoporosity are synthesized using the evaporation–induced self–assembly (EISA) approach. The model materials are then exposed to a controlled atmosphere of CO/H2 at 300 °C. Physicochemical analysis of the treated materials indicates that all oxides convert into carbides with a core–shell structure. The structure appears to consist of crystalline carbide cores surrounded by a partially oxidized carbide shell of low crystallinity. Larger crystallites in the original iron oxide result in larger carbide cores. The presented simple route for the synthesis and analysis of soft–templated iron carbide films will enable the elucidation of the dynamics of the oxide to carbide transformation in future work.

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Influence of Serum Supplemented Cell Culture Medium on Colloidal Stability of Polymer Coated Iron Oxide and Polystyrene Nanoparticles With Impact on Cell Interactions In Vitro

IEEE Transactions on Magnetics ◽

10.1109/tmag.2012.2222634 ◽

2013 ◽

Vol 49 (1) ◽

pp. 402-407 ◽

Cited By ~ 7

Author(s):

Vera Hirsch ◽

Jatuporn Salaklang ◽

Barbara Rothen-Rutishauser ◽

Alke Petri-Fink

Keyword(s):

Cell Culture ◽

Iron Oxide ◽

Culture Medium ◽

Colloidal Stability ◽

Cell Interactions ◽

Cell Culture Medium ◽

Polystyrene Nanoparticles

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The Effect of pH and Viscosity on Magnetophoretic Separation of Iron Oxide Nanoparticles

Magnetochemistry ◽

10.3390/magnetochemistry7060080 ◽

2021 ◽

Vol 7 (6) ◽

pp. 80

Author(s):

Leonie Wittmann ◽

Chiara Turrina ◽

Sebastian P. Schwaminger

Keyword(s):

Iron Oxide ◽

Iron Oxide Nanoparticles ◽

Colloidal Stability ◽

Downstream Processing ◽

Physicochemical Characteristics ◽

Particle Migration ◽

Aggregation Behavior ◽

Oxide Nanoparticles ◽

Separation Processes ◽

Effect Of Ph

Magnetic nanoparticles (MNPs) are used for magnetophoresis-based separation processes in various biomedical and engineering applications. Essential requirements are the colloidal stability of the MNPs and the ability to be separated even in low magnetic field gradients. Bare iron oxide nanoparticles (BIONs) with a diameter of 9.2 nm are synthesized via coprecipitation, exhibiting a high saturation magnetization of 70.84 Am2 kg−1 and no remanence. In our study, zeta potential, dynamic light scattering (DLS), and sedimentation analysis show that the aggregation behavior of BIONs is influenced by pH and viscosity. Small aggregate clusters are formed with either low or high pH values or increased viscosity. Regarding magnetophoresis-based separation, a higher viscosity leads to lower magnetophoretic velocities, similar to how small aggregates do. Additionally, cooperative magnetophoresis, the joint motion of strongly interacting particles, affects the separation of the BIONs, too. Our study emphasizes the effect of pH and viscosity on the physicochemical characteristics of MNPs, resulting in different aggregation behavior. Particularly, for high viscous working media in downstream processing and medicine, respectively, the viscosity should be taken into account, as it will affect particle migration.

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LAPONITE®-stabilized iron oxide nanoparticles for in vivo MR imaging of tumors

Biomaterials Science ◽

10.1039/c5bm00508f ◽

2016 ◽

Vol 4 (3) ◽

pp. 474-482 ◽

Cited By ~ 24

Author(s):

Ling Ding ◽

Yong Hu ◽

Yu Luo ◽

Jianzhi Zhu ◽

Yilun Wu ◽

...

Keyword(s):

Iron Oxide ◽

Mr Imaging ◽

Iron Oxide Nanoparticles ◽

Colloidal Stability ◽

Coprecipitation Method ◽

Oxide Nanoparticles

LAPONITE®-stabilized iron oxide nanoparticles with great colloidal stability and high T2 relaxivity are synthesized by a facile controlled coprecipitation method, and can significantly enhance the contrast of tumors in vivo, indicating their tremendous potential in MR imaging applications.

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