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Background: One of the future applications of magnetic nanoparticles is the development of new iron-oxide-based magnetic resonance imaging (MRI) negative contrast agents, which are intended to improve the results of diagnostics and complement existing Gd-based contrast media.Results: Iron oxide nanoparticles designed for use as MRI contrast media are precisely examined by a variety of methods: powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, Mössbauer spectroscopy and zero-field nuclear magnetic resonance (ZF-NMR) spectroscopy. TEM and XRD measurements reveal a spherical shape of the nanoparticles with an average diameter of 5–8 nm and a cubic spinel-type crystal structure of space group Fd−3m. Raman, Mössbauer and NMR spectroscopy clearly indicate the presence of the maghemite γ-Fe2O3 phase. Moreover, a difference in the magnetic behavior of uncoated and human serum albumin coated iron oxide nanoparticles was observed by Mössbauer spectroscopy.Conclusion: This difference in magnetic behavior is explained by the influence of biofunctionalization on the magnetic and electronic properties of the iron oxide nanoparticles. The ZF-NMR spectra analysis allowed us to determine the relative amount of iron located in the core and the surface layer of the nanoparticles. The obtained results are important for understanding the structural and magnetic properties of iron oxide nanoparticles used as T2 contrast agents for MRI.

The scientific and technical literature addressing the synthesis of anisotropic iron-oxide nanoparticles of various shapes (cubic, rod-like, clustered, etc.) sized from 10 to 100 nm and their application for diagnostic magnetic resonance imaging (MRI) of tissues and organs is analyzed. The analysis indicates that the nanoparticle shape, size, and surface chemistry affect considerably relaxation parameters T1 and T2. Thus, cubic iron-oxide nanoparticles had the greatest T2 values. Furthermore, rod-like and octapodal nanoparticles also exhibit rather high T2 values so that they can be used as contrast agents for diagnostic MRI.

We synthesized a fluorescence conjugate and modified magnetite-gold nanoparticles carrying prostate specific membrane antigen (PSMA) as the ligand. Analysis of their binding to human prostate cancer cell lines PC-3 (PSMA-) and LNCaP (PSMA+) showed selective interaction of the synthesized conjugate and modified nanoparticles with LNCaP cells. These findings suggest that these nanoparticles can be used in tissue-specific magnetic-resonance imaging.

In this work we present the results of the synthesis of magnetite–gold nanoparticles with a core–shell structure. The preparation is carried out in several stages: synthesis of the core, coating with a gold shell, purification of magnetite–gold particles from an uncoated magnetite, and functionalization of the surface with sulfur-containing ligands. The conditions needed for the functionalization of nanoparticles with lipoic acid and mercapto-methoxy polyethylene glycol are indicated in detail, making it possible to determine the optimal conditions needed to achieve an efficient purification and a maximum concentration of the particles in a solution required for biological tests. The possibility of remotely controlling the chymotrypsin properties using an alternating magnetic field has been demonstrated by the example of magnetite–gold nanoparticles. The magnetite–gold nanoparticles which we have obtained are promising for future biomedical applications.

Herein we report on the synthesis, optimization of the synthetic procedure, functionalization, and characterization of cubic and spherical superparamagnetic magnetite nanoparticles. Spherical nanoparticles (16 ± 2 nm) were synthesized using oleylamine and oleic acid, and cubic (20 ± 2, 5 ± 0.5 nm) nanoparticles were synthesized with oleic acid and small amounts of oleylamine. Covalent modification of the nanoparticles was carried out using heterobifunctional PEG with aminopropyltriethoxysilane and N-hydroxysuccinimide ester moieties. This modification makes both water emulsion stability and further modification of the nanoparticles with cytotoxic drugs possible.

We demonstrated the possibility of penetration of magnetite-gold nanoparticles conjugated with prostate-specific membrane antigen into mouse macrophages. It was found that after 3-h incubation with nanoparticles in a concentration of 15 mg/liter at 37oC, they were seen in only 13% macrophages. In about 90% cells, the nanoparticles were detected within the cytoplasm. Under these conditions, membrane damage was revealed in 25% cells. These results should be taken into account in further development and application of nanomaterials for diagnostic and therapeutic purposes in oncology.

Gold nanoparticles that have an average size of 2.2 nm and are modified bo bis[13-(pyridine-4-yl)tridecyl]disulfide have been synthesized, and their aggregation upon interaction with Cu(ClO4) · 6H2O and Co(ClO4) · 6H2O has been investigated. new method to obtain gold nanoparticle ensembles of different shapes and aggregations continues on the basis of the coordination interaction of ligands adsorbed on the surface of gold nanoparticles with a transition metal ions.

A facile and convenient method is offered for the synthesis of composite material consisting of 1,4-bis(terpyridine-4′-yl)benzene microcrystals and gold nanoparticles with an average size of ∼15 nm adsorbed on their surfaces. The nanohybrid material is obtained by the deposition of presynthesized nanoparticles on the surface of the organic compound.