Magnetic Nanoparticle Systems for Nanomedicine—A Materials Science Perspective

Iron oxide nanoparticles are the basic components of the most promising magneto-responsive systems for nanomedicine, ranging from drug delivery and imaging to hyperthermia cancer treatment, as well as to rapid point-of-care diagnostic systems with magnetic nanoparticles. Advanced synthesis procedures of single- and multi-core iron-oxide nanoparticles with high magnetic moment and well-defined size and shape, being designed to simultaneously fulfill multiple biomedical functionalities, have been thoroughly evaluated. The review summarizes recent results in manufacturing novel magnetic nanoparticle systems, as well as the use of proper characterization methods that are relevant to the magneto-responsive nature, size range, surface chemistry, structuring behavior, and exploitation conditions of magnetic nanosystems. These refer to particle size, size distribution and aggregation characteristics, zeta potential/surface charge, surface coating, functionalization and catalytic activity, morphology (shape, surface area, surface topology, crystallinity), solubility and stability (e.g., solubility in biological fluids, stability on storage), as well as to DC and AC magnetic properties, particle agglomerates formation, and flow behavior under applied magnetic field (magnetorheology)

SANS contrast variation study of magnetoferritin structure at various iron loading

Magnetoferritin, a synthetic derivate of iron storage protein – ferritin, has been synthesized with different iron oxide loading values. Small-angle neutron scattering experiments were applied to study the structure of magnetoferritin solutions using contrast variation method by varying the light to heavy water ratio of the solvent. Higher iron loading leads to increase of the neutron scattering length density of magnetoferritin and also to the increase of the polydispersity of complexes. The formation of the magnetic core and the variation of the protein shell structure upon iron loading are concluded

The effect of solution pH on the structural stability of magnetoferritin

The structural stability of magnetoferritin, a synthetic analogue of ferritin, at various pH levels is assessed here. The structural and electrical properties of the complexes were determined by small-angle X-ray scattering (SAXS), dynamic light scattering (DLS) and zeta potential measurements. At pH 3 − 6 a reduction of electrostatic repulsion on the suspended colloids resulted in aggregation and sedimentation of magnetoferritin. At neutral to slightly alkaline conditions (pH 7–9) the magnetoferritin structure was stable for lower iron loadings. Higher solution pH 10–12 induced destabilization of the protein structure and dissociation of subunits. Increasing the loading factor in the MFer complex leads to decrease of the stability versus pH changes

Magnetic Nanoparticle Systems for Nanomedicine—A Materials Science Perspective

Iron oxide nanoparticles are the basic components of the most promising magneto- responsive systems for nanomedicine, ranging from drug delivery and imaging to hyperthermia cancer treatment, as well as to rapid point-of-care diagnostic systems with magnetic nanoparticles. Advanced synthesis procedures of single- and multi-core iron-oxide nanoparticles with high magnetic moment and well-defined size and shape, being designed to simultaneously fulfill multiple biomedical functionalities, have been thoroughly evaluated. The review summarizes recent results in manufacturing novel magnetic nanoparticle systems, as well as the use of proper characterization methods that are relevant to the magneto-responsive nature, size range, surface chemistry, structuring behavior, and exploitation conditions of magnetic nanosystems. These refer to particle size, size distribution and aggregation characteristics, zeta potential/surface charge, surface coating, functionalization and catalytic activity, morphology (shape, surface area, surface topology, crystallinity), solubility and stability (e.g., solubility in biological fluids, stability on storage), as well as to DC and AC magnetic properties, particle agglomerates formation, and flow behavior under applied magnetic field (magnetorheology)

Interaction of mono-carboxylic acids in benzene studied by small-angle neutron scattering

The intermolecular interaction of non-saturated (oleic acid) and saturated (stearic and myristic acids) mono-carboxylic acids in a non-polar organic solvent (deuterated benzene) is derived from the concentration dependence of the small-angle neutron scattering. The excluded volume repulsion dominates over the attraction (supposed due to van der Waals forces) for oleic and myristic acids. In turn, for stearic acid the attractive component is higher than the repulsive one; this results in a shift of the transition into the liquid crystalline state (because of molecule anisotropy) towards smaller concentrations and could explain early data on worse stabilization properties of stearic acid in ferrofluids compared to oleic and myristic acids

On a specific state of C60_{60} fullerene in N-methyl-2-pyrrolidone solution: Mass spectrometric study

A solution of fullerene C$_{60}$ in N-methylpyrrolidone (NMP) presents a suitable system for obtaining fullerene's clusters with the tunable size. However, the mechanism of fullerenes interaction with polar NMP molecules is still elusive. Herein, we present the measured laser desorption/ionization mass spectra (LDI MS) of the precipitates produced from C$_{60}$/NMP solutions of different age in comparison with the typical spectra of C$_{60}$ crystallized from toluene and benzene. The distinctive characteristics of the C$_{60}$/NMP mass spectra were identified and carefully examined. The number of characteristic peaks and their relative intensities in the spectra strongly depend on the age of initial C$_{60}$/NMP solutions. This effect was attributed to the specific C$_{60}$-NMP interactions in the solution, namely to the formation of charge-transfer complexes of C$_{60}$ with NMP molecules followed by fullerene cluster formation. The results of additional measurements carried out by means of small-angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR), UV–Vis absorption spectroscopy together with the density functional theory (DFT) calculations are in accord with the proposed hypothesis