Ecotoxicological assessment of magnetite and magnetite/Ag nanoparticles on terrestrial and aquatic biota from different trophic levels.

The aim of the study is an ecotoxicological assessment of magnetite iron oxide-based nanoparticles (NPs), which have risen in popularity in the last decade, on selected terrestrial and aquatic organisms from various levels of the food chain. In the presented study various organisms, from both the terrestrial and aquatic environment, were used as targets for the assessment of NPs ecotoxicity. Plants (radish, oat), marine bacteria (A. fischeri) and crustacean (H. incongruens) were used to represent producers, decomposers, and consumers, respectively. It was found that examined NPs were harmful (to a different degree) to biota from three different trophic levels. Physicochemical characterization (size/morphology, crystallinity, composition, and magnetic properties) of the tested nanoparticles was performed by: transmission electron microscopy, X-ray diffraction, energy dispersive spectroscopy, and Mossbauer spectroscopy, respectively. Phytotoxicity was evaluated according to the OECD 208 Guideline, while acute and chronic toxicity of NPs was conducted using bioassays employing bacteria and crustacea, respectively. The phytotoxicity of all investigated iron oxide-based NPs was dependent on concentration and type of NPs formulation and was measured via biomass, seed germination, root length, shoot height, and content of plant pigments. Increasing the concentration of NPs increased phytotoxicity and mortality of aquatic organisms. Ecotoxicity of iron oxide/silver was dependent on the size and content of silver. Iron oxide NPs coated with nanosilver in a percentage ratio of 69/31 were found to be the most toxic on tested terrestrial and aquatic biota.

Synthesis and characterization of modified magnetic nanoparticles as theranostic agents: in vitro safety assessment in healthy cells.

Over the past few decades nanotechnology has paved its way into cancer treatment procedures with the use of nanoparticles (NPs) for contrast media and therapeutic agents. Iron based NPs are the most investigated since they can be used for drug delivery, imaging and when magnetically activate employed as local heat sources in cancer hyperthermia. In this work, was performed synthesis, characterization and biological evaluation of different types of iron oxide nanoparticles (mNPs'), as promising material for tumor hyperthermia. The surface of mNPs' has modified with inorganic stabilizing agents to particularly improve characteristics such as their magnetic properties, colloidal stability and biocompatibility. The successful coating of mNPs' was confirmed by morphological and structural characterization by transmission electron microscopy (TEM) and Fourier-Transform Infra-Red spectroscopy (FT-IR), while their hydrodynamic diameter was studied by using Dynamic light scattering (DLS). X-ray Diffraction (XRD) proved that the crystallite phase of mNPs' is the same with the pattern of magnetite. Superparamagnetic behavior and mNPs' response under the application of alternating magnetic field (AMF) were also thoroughly investigated and showed good heating efficiency in magnetic hyperthermia experiments. The contrast ability in magnetic resonance imaging (MRI) is also discussed indicating that mNPs are negative MRI contrast types. Nonetheless the effects of mNPs on cell viability was performed by MTT on human keratinocytes, human embryonic kidney cells, endothelial cells and by hemolytic assay on erythrocytes. In healthy keratinocytes wound healing assay in different time intervals was performed, assessing both the cell migration and wound closure. Endothelial cells have also been studied in functional activity performing capillary morphogenesis. In vitro studies showed that mNPs are safely taken by the healthy cells and do not interfere with the biological processes such as cell migration and motility.