Systematic investigations of the mechanisms and effects of engineered nanomaterial interactions with living systems and/or the environment

Especially in recent years, the production of particles on the nanometer scale has increased. These particles are widely studied in academic and industrial fields and are called nanoparticles. The production of nanoparticles, their wide usege area from food products to cosmetics, and the rate of human exposure to nanoparticles have increased day by day and become widespread. Nonetheless, there has been a great increase in the production and application areas of various types of nanoparticles, and although the researches that studied their effects after exposure to these particles have increased in the same proportion, there has been no consensus among them due to the lack of a systematic study. From this point of view, in this study, it is aimed to systematically investigate in vitro and in vivo toxicities of oxide nanoparticles of various shapes, sizes and types that interact with cells. The commercially purchased bare titanium dioxide (TiO2, E171) nanoparticles, irregular shape and sized bare and amino propyl silane (APTES) modified iron oxide (Fe3O4) nanoparticles, and spheric and uniform bare and 3-amino propyl silane (APTES) modified iron oxide (Fe3O4) nanoparticles were used. Various characterization techniques have been carried out to determine the physical and chemical properties of these nanoparticles. Dynamic light scattering (DLS) to obtain general information about the dispersion and particle size in the solvent, transmission electron microscopy (TEM) for surface morphology and topography analysis, X-ray ray photoelectron spectroscopy (XPS) to analyze surface chemical structure and whether surface modifications are successful or not, X-ray diffraction (XRD) spectroscopy to investigate crystal structure and crystal properties, Branauer-Emmet-Teller (BET) for surface area and pore diameter analysis, vibration sample magnetometry (VSM) methods for the magnetic properties and characteristics of iron oxide nanoparticles were used. Cell viability assay (MTT) and oxidative stress experiments were carried out to determine the toxic properties of nanoparticles. For this purpose, the cytotoxicity of nanoparticles with spherical shape and homogeneous size distribution was evaluated with MTT results at 7.81-500 µg/ml concentrations by using human epithelium colorectal adenocarcinoma (CaCo-2) cell line in vitro. Then, oxidative stress properties at IC50 / 2 and IC50 / 4 concentrations were investigated. For the in vivo genotoxic effect and life treatment toxicity of spheric and uniform iron oxide nanoparticles experiments were carried out at 1, 5, 10, 50 and 100 mg nano-Fe3O4 concentrations per kg of sediment using freshwater midge Chironomus riparius larvae. At the end of the study, the surface modification of the nanoparticles was successfully performed. By determining the physical and chemical properties of nanoparticles, in vivo and in vitro experiments were performed to evaluate their toxic properties systematically.