Synthesis and cytotoxicity assessment of superparamagnetic iron-gold core-shell nanoparticles coated with polyglycerol

Characterization of electroless Ni-coated Fe–Co composite using powder metallurgy

This study covers composite production and characterization of powders obtained by applying the electroless Ni coating technique to Fe–Co powders by microwave sintering technique. The physical, mechanical, and electrical properties of electroless Ni-coated Fe and Co composites samples produced in different compositions by sintering magnetic materials in a microwave oven at 1,100°C were characterized. With the electroless coating technique, a uniform nickel deposit on the Fe–Co particles was coated before sintering with the precipitation procedure. A composite consisting of metallic phase, Fe–Co, and triple additions in a Ni matrix was prepared in an argon atmosphere and sintered by microwave technique. X-ray diffraction, scanning electron microscope, and impedance phase analyzer were used to obtain structural data in the temperature range of 25–40°C and to determine magnetic and electrical properties such as dielectric and conductivity. The ferromagnetic resonance was varied between 10 Hz and 1 GHz, and measurements were made to characterize the properties of the samples. Numerical findings obtained for 25% Ni composition at 1,100°C (Fe–37.5% Co) suggest that the best conductivity and hardness are obtained by adding 25Ni at 1,100°C sintering temperature.

A Perspective on Modelling Metallic Magnetic Nanoparticles in Biomedicine: From Monometals to Nanoalloys and Ligand-Protected Particles

The focus of this review is on the physical and magnetic properties that are related to the efficiency of monometallic magnetic nanoparticles used in biomedical applications, such as magnetic resonance imaging (MRI) or magnetic nanoparticle hyperthermia, and how to model these by theoretical methods, where the discussion is based on the example of cobalt nanoparticles. Different simulation systems (cluster, extended slab, and nanoparticle models) are critically appraised for their efficacy in the determination of reactivity, magnetic behaviour, and ligand-induced modifications of relevant properties. Simulations of the effects of nanoscale alloying with other metallic phases are also briefly reviewed.

Magnetic nanoparticles applied in targeted therapy and magnetic resonance imaging: crucial preparation parameters, indispensable pre-treatments, updated research advancements and future perspectives

Magnetic nanoparticles (MNPs) have attracted much attention in cancer treatment as carriers for drug delivery and imaging contrast agents due to their distinctive performances based on their magnetic properties and nanoscale structure. In this review, we aim to comprehensively dissect how the applications of MNPs in targeted therapy and magnetic resonance imaging are achieved and their specificities by focusing on the following aspects: (1) several important preparation parameters (pH, temperature, ratio of the reactive substances, etc.) that have crucial effects on the properties of MNPs, (2) indispensable treatments to improve the biocompatibility, stability, and targeting ability of MNPs and prolong their circulation time for biomedical applications, (3) the mechanism for MNPs to deliver and release medicine to the desired sites and be applied in magnetic hyperthermia as well as related updated research advancements, (4) comparatively promising research directions of MNPs in magnetic resonance imaging, and (5) perspectives in the further optimization of their preparations, pre-treatments and applications in cancer diagnosis and therapy.

New advances on Au-magnetic organic hybrid core-shells in MRI, CT imaging, and drug delivery

Magnetic nanoparticles have been widely studied for various scientific and technological applications such as magnetic storage media, contrast agents for magnetic resonance imaging (MRI), biolabelling, separation of biomolecules, and magnetic-targeted drug delivery. A new strategy on Au-magnetic nano-hybrid core-shells was applied in MRI, CT imaging, and drug delivery, which has been received much attention nowadays. Herein, the designing of different magnetic core-shells with Au in MRI and cancer treatment is studied.

Core–shell nanoparticles used in drug delivery-microfluidics: a review

Developments in the fields of lab-on-a-chip and microfluidic technology have benefited nanomaterial production processes due to fluid miniaturization. The ability to acquire, manage, create, and modify structures on a nanoscale is of great interest in scientific and technological fields. Recently, more attention has been paid to the production of core–shell nanomaterials because of their use in various fields, such as drug delivery. Heterostructured nanomaterials have more reliable performance than the individual core or shell materials. Nanoparticle synthesis is a complex process; therefore, various techniques exist for the production of different types of nanoparticles. Among these techniques, microfluidic methods are unique and reliable routes, which can be used to produce nanoparticles for drug delivery applications.

Developments in the fields of lab-on-a-chip and microfluidic technology have benefited nanomaterial production processes due to fluid miniaturization.

Radioiodination of cyclin dependent kinase inhibitor Olomoucine loaded Fe@Au nanoparticle and evaluation of the therapeutic efficacy on cancerous cells

Magnetic nanoparticles have promising biomedical applications such as drug delivery, novel therapeutics and diagnostic imaging. Magnetic drug delivery combination works on the delivery of magnetic nanoparticles loaded with drug to the target tissue by means of an external magnetic field. Gold coated iron oxide (Fe@Au) nanoparticles can provide useful surface chemistry and biological reactivity. Covalent conjugation to the Fe@Au nanoparticles through cleavable linkages can be used to deliver drugs to tumor cells, then the drug can be released by an external. In this paper, purine based cyclin dependent kinases (CDKs) inhibitor Olomoucine (Olo) [2-(Hydroxyethylamino)-6-benzylamino-9-methylpurine] was loaded on gold coated iron oxide (Fe@Au) nanoparticles and radiolabeled with 131I to combine magnetic targeted drug delivery and radiotherapy. Fe@Au nanoparticles were synthesized by microemulsion method. The characterization of nanoparticles was examined by TEM, VSM and XRD. Amine activation was utilized by cysteamine hydrochloride and then CDI was used for conjugation of Olomoucine. Antiproliferative effect and cytotoxicity of Olomoucine loaded Fe@Au nanoparticles (Fe@Au-Olo) were investigated on MCF7 and A549 cell lines. Proliferation rate was decreased while uptake of Fe@Au-Olo on both cell lines was high in comparison with Olomoucine. Also, enhanced incorporation ratio was observed under external magnetic field.

Multifunctional metal-polymer nanoagglomerates from single-pass aerosol self-assembly

In this study, gold (Au)-iron (Fe) nanoagglomerates were capped by a polymer mixture (PM) consisting of poly(lactide-co-glycolic acid), protamine sulfate, and poly-l-lysine via floating self-assembly in a single-pass aerosol configuration as multibiofunctional nanoplatforms. The Au-Fe nanoagglomerates were directly injected into PM droplets (PM dissolved in dichloromethane) in a collison atomizer and subsequently heat-treated to liberate the solvent from the droplets, resulting in the formation of PM-capped Au-Fe nanoagglomerates. Measured in vitro, the cytotoxicities of the nanoagglomerates (>98.5% cell viability) showed no significant differences compared with PM particles alone (>98.8%), thus implying that the nanoagglomerates are suitable for further testing of biofunctionalities. Measurements of gene delivery performance revealed that the incorporation of the Au-Fe nanoagglomerates enhanced the gene delivery performance (3.2 × 10⁶ RLU mg⁻¹) of the PM particles alone (2.1 × 10⁶ RLU mg⁻¹), which may have been caused by the PM structural change from a spherical to a hairy structure (i.e., the change followed the agglomerated backbone). Combining the X-ray-absorbing ability of Au and the magnetic property of Fe led to magnetic resonance (MR)-computed tomography (CT) contrast ability in a phantom; and the signal intensities [which reached 64 s⁻¹T₂-relaxation in MR and 194 Hounsfield units (HUs) in CT at 6.0 mg mL⁻¹] depended on particle concentration (0.5–6.0 mg mL⁻¹).

Growth arrest and rapid capture of select pathogens following magnetic nanoparticle treatment

Thorough understanding of magnetic nanoparticle (MNP) properties is essential for developing new theranostics. In this study, we provide evidence that non-modified magnetic iron oxide nanoparticles and their functionalized derivatives may be used to restrict growth and capture different pathogens. Coprecipitation of Fe(2+) and Fe(3+) ions in an alkaline solution was used to synthesize MNPs that subsequently were functionalized by gold and aminosilane coating. Transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to assess their physicochemical properties. A significant decrease of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans outgrown from medium after addition of MNPs or their derivatives was observed during 24h culture. Measurement of optical density revealed that using MNPs, these pathogens can be quickly captured and removed (with efficiency reaching almost 100%) from purposely infected saline buffer and body fluids such as human blood plasma, serum, abdominal fluids and cerebrospinal fluids. These effects depend on nanoparticle concentration, surface chemistry, the type of pathogen, as well as the surrounding environment.

Polyamidoamine and polyglycerol; their linear, dendritic and linear–dendritic architectures as anticancer drug delivery systems

This review covers the latest advances in the conjugation of chemotherapeutics such as doxorubicin, paclitaxel, methotrexate, fluorouracil and cisplatin to dendritic polymers, including polyamidoamine dendrimers, hyperbranched polyglycerols and their linear analogues, with a focus on their cytotoxicity, biodistribution and biodegradability.

Core/shell nanoparticles in biomedical applications

Nanoparticles have several exciting applications in different areas and biomedial field is not an exception of that because of their exciting performance in bioimaging, targeted drug and gene delivery, sensors, and so on. It has been found that among several classes of nanoparticles core/shell is most promising for different biomedical applications because of several advantages over simple nanoparticles. This review highlights the development of core/shell nanoparticles-based biomedical research during approximately past two decades. Applications of different types of core/shell nanoparticles are classified in terms of five major aspects such as bioimaging, biosensor, targeted drug delivery, DNA/RNA interaction, and targeted gene delivery.

Cytotoxicity of Magnetic Nanoparticles on Normal and Malignant Human Skin Cells

Magnetic nanoparticles have received considerable attention in nanomedicine due to their potential application as therapeutic or diagnostic tools based on their particular properties. However, prior to clinical application investigating the effect of these nanoparticles on cells is essential. The aim of the following study is therefore to evaluate the cytotoxicity of magnetic ( Fe 3 O 4) and gold-coated magnetic nanoparticles ( Fe 3 O 4@ Au ) on various cell lines in order to clarify the risk of these materials for human use. Toxicity of these nanoparticles on human dermal fibroblasts (SKIN), human squamous cell carcinoma cells (A431 cells) and human epidermal keratinocytes ( HaCaT cells) were determined using the MTT assay. Results showed that, within the used concentration range, Fe 3 O 4 nanoparticles had no significant effect on all investigated cell lines, while Fe 3 O 4@ Au nanoparticles seem to have a moderate toxicity on all cell lines with some selectivity for the malignant cells, although it is yet moderate. The different characteristic of the cell lines' survival with respect to incubation time and nanoparticle concentration could be partly due to different cell death modes. Therefore, the prepared Fe 3 O 4 nanoparticles are harmless and could be applied safely for skin cancer treatment or diagnosis.

Formulation design facilitates magnetic nanoparticle delivery to diseased cells and tissues

Magnetic nanoparticles (MNPs) accumulate at disease sites with the aid of magnetic fields; biodegradable MNPs can be designed to facilitate drug delivery, influence disease diagnostics, facilitate tissue regeneration and permit protein purification. Because of their limited toxicity, MNPs are widely used in theranostics, simultaneously facilitating diagnostics and therapeutics. To realize therapeutic end points, iron oxide nanoparticle cores (5-30 nm) are encapsulated in a biocompatible polymer shell with drug cargos. Although limited, the toxic potential of MNPs parallels magnetite composition, along with shape, size and surface chemistry. Clearance is hastened by the reticuloendothelial system. To surmount translational barriers, the crystal structure, particle surface and magnetic properties of MNPs need to be optimized. With this in mind, we provide a comprehensive evaluation of advancements in MNP synthesis, functionalization and design, with an eye towards bench-to-bedside translation.

Engineered magnetic nanoparticles for biomedical applications

In the past decades, magnetic nanoparticles (MNPs) have been used in wide range of diverse applications, ranging from separation to sensing. Here, synthesis and applications of functionalized MNPs in the biomedical field are discussed, in particular in drug delivery, imaging, and cancer therapy, highlighting also recent progresses in the development of multifunctional and stimuli-responsive MNPs. The role of their size, composition, and surface functionalization is analyzed, together with their biocompatibility issues.

Effect of particle size of hydroxyapatite nanoparticles on its biocompatibility

Nano-particulate biomaterials have been used in clinical diagnosis and treatment, as drug carrier or in cosmetics because of their excellent performance properties. The toxicity and biocompatibility of nanoparticles (NPs), however, are always a focused concern for a doctor or a scientist. At present, there is almost no systemic evaluation standard or testing methods of safety for nanoparticles. In this study, two kinds of hydroxylapatite, (HAP) NPs with different particle sizes were selected. A number of biocompatibility tests in vivo or in vitro were conducted. They were cytotoxicity (MTT assay), genotoxicity (Ames, Mouse Lymphoma Mutagenesis Assay), and systemic toxicity (Acute and Subacute). The results indicated that, under the concentration of 100 mg/L, both HAP NPs could cause significant inhibition of cell growth. The size of NPs might have close tie with cell response. The mutagenic test in vitro was negative in this study. Histopathological findings showed that both kinds of HAP NPs could induce pseudotubercles in lung. Moreover, smaller size of nanoparticles resulted in a vacuolar degeneration of nephric tubule epithelium at 7 days post-intraveneous injection. The results implied that the size of NPs might play an important role in the biocompatibility of the materials. The kidney might be the main organ of discharge of nanoparticles from body.

Research Development on the Preparation of Gold-Coated Magnetic Nanoparticles

The study of core@shell magnetic nanoparticles (MNPs) has a wide range of applications because of the unique combination of the nanoscale magnetic core and the functional shell. In this paper, a brief review is presented on the different methods for the preparation of gold-coated composite magnetic nanoparticles, along with our preliminary work on the synthesis of gold-coated alloy nanoparticles.

The synthesis and characterization of poly(γ-glutamic acid)-coated magnetite nanoparticles and their effects on antibacterial activity and cytotoxicity

Magnetite nanoparticles (MNPs) modified with sodium and calcium salts of poly(γ-glutamic acid) (NaPGA and CaPGA) were synthesized by the coprecipitation method, followed by characterization and evaluation of their antibacterial and cytotoxic effects. Superparamagnetic MNPs are particularly attractive for magnetic driving as well as bacterial biofilm and cell targeting in in vivo applications. Characterization of synthesized MNPs by the Fourier transform infrared spectra and magnetization curves confirmed the PGA coating on MNPs. The mean diameter of NaPGA- and CaPGA-coated MNPs as determined by transmission electron microscopy was 11.8 and 14 nm, respectively, while the x-ray diffraction pattern revealed the as-synthesized MNPs to be pure magnetite. Based on agar dilution assay, both NaPGA- and CaPGA-coated MNPs showed a lower minimum inhibitory concentration in Salmonella enteritidis SE 01 than the commercial antibiotics linezolid and cefaclor, but the former was effective against Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 10832, whereas the latter was effective against Escherichia coli O157:H7 TWC 01. An in vitro cytotoxicity study in human skin fibroblast cells as measured by MTT assay implied the as-synthesized MNPs to be nontoxic. This outcome demonstrated that both γ-PGA-modified MNPs are cytocompatible and possess antibacterial activity in vitro, and thereby should be useful in in vivo studies for biomedical applications.

Magnetically recoverable magnetite/gold catalyst stabilized by poly(N-vinyl-2-pyrrolidone) for aerobic oxidation of alcohols

Fe₃O₄:PVP/Au nanocomposite synthesized via a two-step procedure was tested as a quasi-homogenous alcohol oxidation catalyst. It was found that the nanocomposite was able to carry out aerobic oxidation of alcohols in water at room temperature. Studies show rapid magnetic recoverability and reusability characteristics.

Probing atomic structure in magnetic core/shell nanoparticles using synchrotron radiation

Core/shell Fe/Cu and Fe/Au nanoparticles were prepared directly by deposition from the gas phase. A detailed study of the atomic structure in both the cores and shells of the nanoparticles was undertaken by means of extended absorption fine structure (EXAFS) measurements. For Fe/Cu nanoparticles, a Cu shell ∼ 20 monolayers thick appears similar in structure to bulk Cu and is sufficient to cause the structure in the Fe core to switch from body centred cubic (bcc; as in bulk Fe) to face centred cubic. This is not the case for thinner Cu shells, 1-2 monolayers in thickness, in which there is a considerable contraction in nearest-neighbour interatomic distance as the shell structure changes to bcc. In Fe/Au nanoparticles, the crystal structure in the Fe core remains bcc for all Au thicknesses although there is some stretching of the lattice. In thin Au shells ∼ 2 monolayers thick, there is strong contraction in interatomic distances. There does not appear to be significant alloying at the Fe/Au interface.

Influence of Gold Nanoshell on Hyperthermia of Super Paramagnetic Iron Oxide Nanoparticles (SPIONs)

Gold nanoshell around super paramagnetic iron oxide nanoparticles (SPIONs) was synthesized and small angle X-ray scattering (SAXS) analysis suggests a gold coating of approximately 0.4 to 0.5 nm thickness. On application of low frequency oscillating magnetic fields (44 - 430 Hz), a four- to five-fold increase in the amount of heat released with gold-coated SPIONs (6.3 nm size) in comparison with SPIONs (5.4 nm size) was observed. Details of the influence of frequencies of oscillating magnetic field, concentration and solvent on heat generation are presented. We also show that, in the absence of oscillating magnetic field, both SPIONs and SPIONs@Au are not particularly cytotoxic to mammalian cells (MCF-7 breast carcinoma cells and H9c2 cardiomyoblasts) in culture, as indicated by the reduction of 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium by viable cells in a phenazine methosulfate-assisted reaction.