One-Pot Reaction and Subsequent Annealing to Synthesis Hollow Spherical Magnetite and Maghemite Nanocages

Red blood cell-derived materials for cancer therapy: Construction, distribution, and applications

Cancer has become an increasingly important public health issue owing to its high morbidity and mortality rates. Although traditional treatment methods are relatively effective, they have limitations such as highly toxic side effects, easy drug resistance, and high individual variability. Meanwhile, emerging therapies remain limited, and their actual anti-tumor effects need to be improved. Nanotechnology has received considerable attention for its development and application. In particular, artificial nanocarriers have emerged as a crucial approach for tumor therapy. However, certain deficiencies persist, including immunogenicity, permeability, targeting, and biocompatibility. The application of erythrocyte-derived materials will help overcome the above problems and enhance therapeutic effects. Erythrocyte-derived materials can be acquired via the application of physical and chemical techniques from natural erythrocyte membranes, or through the integration of these membranes with synthetic inner core materials using cell membrane biomimetic technology. Their natural properties such as biocompatibility and long circulation time make them an ideal choice for drug delivery or nanoparticle biocoating. Thus, red blood cell-derived materials are widely used in the field of biomedicine. However, further studies are required to evaluate their efficacy, in vivo metabolism, preparation, design, and clinical translation. Based on the latest research reports, this review summarizes the biology, synthesis, characteristics, and distribution of red blood cell-derived materials. Furthermore, we provide a reference for further research and clinical transformation by comprehensively discussing the applications and technical challenges faced by red blood cell-derived materials in the treatment of malignant tumors.

Hollow Iron Oxide Nanospheres Obtained through a Combination of Atomic Layer Deposition and Electrospraying Technologies

In the present study, we report on the successful synthesis of hollow iron oxide nanospheres. The hollow Fe₃O₄ nanospheres were synthesized following a four-step procedure: electrospraying spherical PVP particles, coating these particles with alumina (Al₂O₃) and hematite (Fe₂O₃) through atomic layer deposition and, finally, a thermal reduction process to degrade the polymer (PVP) and convert hematite (Fe₂O₃) into magnetite (Fe₃O₄). A structural analysis using X-ray diffraction (XRD) confirmed the effectiveness of the thermal reduction process. A morphological analysis confirmed that the four-step procedure allowed for the obtainment of hollow iron oxide nanospheres, even though the reduction process caused a contraction in the diameter of the particles of almost 300 nm, but did not affect the thickness of the walls of the hollow spheres that remained at approximately 15 nm. Magnetic properties of the hollow iron oxide nanospheres enable their use in applications where the agglomeration of magnetic nanostructures in liquid media is commonly not allowed, such as in drug encapsulation and delivery.

An Investigation of the Mechanism Magnetite Precipitation Using Ammonium Carbonate

The purpose of this study is to determine the phase composition of iron oxide compounds formed during precipitation by ammonium carbonate hydrolysis products, to establish the magnetite formation regions and the kinetic characteristics of the reaction formation Fe3O4. Characterization by X-ray diffraction (XRD) indicated that magnetite is formed in a solution of ferrous sulphate during the hydrolysis of ammonium carbonate. It has a homogeneous phase composition and a cubic crystal structure. Phase diagrams of the formation of the crystalline phase of magnetite, goethite and ferric hydroxide have been determined. It has been established that magnetite with a spinel structure is formed under controlled slow precipitation from ferrous sulphate with an ammonium carbonate solution. The calculation of the kinetic characteristics of the reactions of solid phase precipitation (a rate constant at different initial concentrations of ferrous sulphate, the order of the reaction) has shown that the process proceeds in two stages with the formation of an intermediate compound and its further oxidation. Moreover, the rate constant of oxidation is 0.654 L/min mol, and the rate constant of the first reaction is much higher – 1.645 L/min mol.

Corn-like, recoverable γ-Fe2O3@SiO2@TiO2 photocatalyst induced by magnetic dipole interactions

Corn-like, γ-Fe2O3@SiO2@TiO2 core/shell heterostructures were synthesized by a modified solvothermal reduction combined with a sol-gel method. SiO2 shells were first deposited on monodisperse Fe3O4 microspheres by a sol-gel method. Fe3O4@SiO2@TiO2 corn-like heterostructures were then obtained by sequential TiO2 coating, during which the magnetic dipolar interactions induced the anisotropic self-assembly process. After annealing at 350 °C, the crystalized TiO2 enhanced photocatalytic activity, while Fe3O4 was converted to γ-Fe2O3. The corn-like γ-Fe2O3@SiO2@TiO2 photocatalyst can be recycled and reused by magnet extraction. Despite the photocatalytic activity decreased with each cycle, it can be completely recovered by moderate heating at 200 °C.

Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications

Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties. Growing interest in designed and surface-engineered iron oxide NPs with multifunctionalities was explored in in vitro/in vivo biomedical applications, focusing on their combined roles in bioseparation, as a biosensor, targeted-drug delivery, MR contrast agents, and magnetic fluid hyperthermia. This review outlines the limitations of extant surface engineering strategies and several developing strategies that may overcome these limitations. This study also details the promising future directions of this active research field.

Shape-controlled iron oxide nanocrystals: synthesis, magnetic properties and energy conversion applications

Iron oxide nanocrystals (IONCs) with various geometric morphologies show excellent physical and chemical properties and have received extensive attention in recent years.

Recent progress on magnetic iron oxide nanoparticles: synthesis, surface functional strategies and biomedical applications

This review focuses on the recent development and various strategies in the preparation, microstructure, and magnetic properties of bare and surface functionalized iron oxide nanoparticles (IONPs); their corresponding biological application was also discussed. In order to implement the practical in vivo or in vitro applications, the IONPs must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of IONPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The new functionalized strategies, problems and major challenges, along with the current directions for the synthesis, surface functionalization and bioapplication of IONPs, are considered. Finally, some future trends and the prospects in these research areas are also discussed.

Recent progress in magnetic iron oxide-semiconductor composite nanomaterials as promising photocatalysts

Photocatalytic degradation of toxic organic pollutants is a challenging tasks in ecological and environmental protection. Recent research shows that the magnetic iron oxide-semiconductor composite photocatalytic system can effectively break through the bottleneck of single-component semiconductor oxides with low activity under visible light and the challenging recycling of the photocatalyst from the final products. With high reactivity in visible light, magnetic iron oxide-semiconductors can be exploited as an important magnetic recovery photocatalyst (MRP) with a bright future. On this regard, various composite structures, the charge-transfer mechanism and outstanding properties of magnetic iron oxide-semiconductor composite nanomaterials are sketched. The latest synthesis methods and recent progress in the photocatalytic applications of magnetic iron oxide-semiconductor composite nanomaterials are reviewed. The problems and challenges still need to be resolved and development strategies are discussed.

An easy and novel approach to prepare Fe3O4–reduced graphene oxide composite and its application for high-performance lithium-ion batteries

A ferroferric oxide–reduced graphene oxide (Fe₃O₄–rGO) composite is prepared by a facile one-step solvothermal method in which the reduction process of graphene oxide (GO) into rGO was accompanied by the generation of Fe₃O₄ particles.

Reassembling nanometric magnetic subunits into secondary nanostructures with controlled interparticle spacing

Nanoparticle clusters have become attractive secondary nanostructures due to their collective physical properties, which can be modulated as a function of their internal structure.

Significantly enhanced dye removal performance of hollow tin oxide nanoparticles via carbon coating in dark environment and study of its mechanism

Understanding the correlation between physicochemical properties and morphology of nanostructures is a prerequisite for widespread applications of nanomaterials in environmental application areas. Herein, we illustrated that the uniform-sized SnO2@C hollow nanoparticles were large-scale synthesized by a facile hydrothermal method. The size of the core-shell hollow nanoparticles was about 56 nm, and the shell was composed of a solid carbon layer with a thickness of 2 ~ 3 nm. The resulting products were characterized in terms of morphology, composition, and surface property by various analytical techniques. Moreover, the SnO2@C hollow nanoparticles are shown to be effective adsorbents for removing four different dyes from aqueous solutions, which is superior to the pure hollow SnO2 nanoparticles and commercial SnO2. The enhanced mechanism has also been discussed, which can be attributed to the high specific surface areas after carbon coating.

Superparamagnetic iron oxide nanoparticles (SPION) for the treatment of antibiotic-resistant biofilms

Bacterial infections caused by antibiotic-resistant strains are of deep concern due to an increasing prevalence, and are a major cause of morbidity in the United States of America. In particular, medical device failures, and thus human lives, are greatly impacted by infections, where the treatments required are further complicated by the tendency of pathogenic bacteria, such as Staphylococcus aureus, to produce antibiotic resistant biofilms. In this study, a panel of relevant antibiotics used clinically including penicillin, oxacillin, gentamicin, streptomycin, and vancomycin are tested, and although antibiotics are effective against free-floating planktonic S. aureus, either no change in biofilm function is observed, or, more frequently, biofilm function is enhanced. As an alternative, superparamagnetic iron oxide nanoparticles (SPION) are synthesized through a two-step process with dimercaptosuccinic acid as a chelator, followed by the conjugation of metals including iron, zinc, and silver; thus, the antibacterial properties of the metals are coupled to the superparamagnetic properties of SPION. SPION might be the ideal antibacterial treatment, with a superior ability to decrease multiple bacterial functions, target infections in a magnetic field, and had activity better than antibiotics or metal salts alone, as is required for the treatment of medical device infections for which no treatment exists today.

Facile method to synthesize magnetic iron oxides/TiO2 hybrid nanoparticles and their photodegradation application of methylene blue

Many methods have been reported to improving the photocatalytic efficiency of organic pollutant and their reliable applications. In this work, we propose a facile pathway to prepare three different types of magnetic iron oxides/TiO2 hybrid nanoparticles (NPs) by seed-mediated method. The hybrid NPs are composed of spindle, hollow, and ultrafine iron oxide NPs as seeds and 3-aminopropyltriethyloxysilane as linker between the magnetic cores and TiO2 layers, respectively. The composite structure and the presence of the iron oxide and titania phase have been confirmed by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectra. The hybrid NPs show good magnetic response, which can get together under an external applied magnetic field and hence they should become promising magnetic recovery catalysts (MRCs). Photocatalytic ability examination of the magnetic hybrid NPs was carried out in methylene blue (MB) solutions illuminated under Hg light in a photochemical reactor. About 50% to 60% of MB was decomposed in 90 min in the presence of magnetic hybrid NPs. The synthesized magnetic hybrid NPs display high photocatalytic efficiency and will find recoverable potential applications in cleaning polluted water with the help of magnetic separation.

Preparation and characterization of spindle-like Fe3O4 mesoporous nanoparticles

Magnetic spindle-like Fe3O4 mesoporous nanoparticles with a length of 200 nm and diameter of 60 nm were successfully synthesized by reducing the spindle-like α-Fe2O3 NPs which were prepared by forced hydrolysis method. The obtained samples were characterized by transmission electron microscopy, powder X-ray diffraction, attenuated total reflection fourier transform infrared spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and nitrogen adsorption-desorption analysis techniques. The results show that α-Fe2O3 phase transformed into Fe3O4 phase after annealing in hydrogen atmosphere at 350°C. The as-prepared spindle-like Fe3O4 mesoporous NPs possess high Brunauer-Emmett-Teller (BET) surface area up to ca. 7.9 m2 g-1. In addition, the Fe3O4 NPs present higher saturation magnetization (85.2 emu g-1) and excellent magnetic response behaviors, which have great potential applications in magnetic separation technology.

One-step synthesis of metallic and metal oxide nanoparticles using amino-PEG oligomers as multi-purpose ligands: size and shape control, and quasi-universal solvent dispersibility

A one-step and room temperature synthesis toward metallic and metal oxide nanoparticles soluble both in water and organic solvent is reported. This was achieved using amino-PEG oligomers that make it possible to control the size and shape of the nanoparticles.

Synthesis and Magnetic Properties of Maghemite (gamma-Fe(2)O(3)) Short-Nanotubes

We report a rational synthesis of maghemite (gamma-Fe(2)O(3)) short-nanotubes (SNTs) by a convenient hydrothermal method and subsequent annealing process. The structure, shape, and magnetic properties of the SNTs were investigated. Room-temperature and low-temperature magnetic measurements show that the as-fabricated gamma-Fe(2)O(3) SNTs are ferromagnetic, and its coercivity is nonzero when the temperature above blocking temperature (T(B)). The hysteresis loop was operated to show that the magnetic properties of gamma-Fe(2)O(3) SNTs are strongly influenced by the morphology of the crystal. The unique magnetic behaviors were interpreted by the competition of the demagnetization energy of quasi-one-dimensional nanostructures and the magnetocrystalline anisotropy energy of particles in SNTs.

Facile Fabrication of Ultrafine Hollow Silica and Magnetic Hollow Silica Nanoparticles by a Dual-Templating Approach

The development of synthetic process for hollow silica materials is an issue of considerable topical interest. While a number of chemical routes are available and are extensively used, the diameter of hollow silica often large than 50 nm. Here, we report on a facial route to synthesis ultrafine hollow silica nanoparticles (the diameter of ca. 24 nm) with high surface area by using cetyltrimethylammmonium bromide (CTAB) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as co-templates and subsequent annealing treatment. When the hollow magnetite nanoparticles were introduced into the reaction, the ultrafine magnetic hollow silica nanoparticles with the diameter of ca. 32 nm were obtained correspondingly. Transmission electron microscopy studies confirm that the nanoparticles are composed of amorphous silica and that the majority of them are hollow.