Investigation of interaction between polystyrene nanoparticles with milk

Although plastics at the micrometer level are still the subject of many researches, studies on nanoplastics are limited. There are few studies reporting the effects of nanoplastics on humans and mammals. In this study, the corona structure of NPSs of different diameters formed around them after interaction with the food matrix, and their behavior in solution with and without the food matrix were investigated. TEM and ESEM imaging and hydrodynamic diameter and zeta potential measurements were performed for the characterization of the particles before and after interaction with the food matrix. Likewise, after digestion, corona formations of the particles alone and with the effect of the food matrix were examined and aggregation states in the solution were observed. When the before and after digestion were compared, it was determined that the particles behaved differently in different digestive environments. Apart from the pre- and post-digestion characterization of the particles, fluorescence measurements of the protein corona they formed and quantitative and qualitative analyzes were made by electrophoresis. NPS-30 was found to be the most protein-binding particle in these analyses. After protein corona analysis, the effects of particles on the activities of digestive enzymes were examined. In this context, amylase, pepsin and lipase were used. It was observed that the particles did not have significant effects on amylase and pepsin activities, but significantly reduced lipase activity in the intestinal environment. In the last stage of the thesis, the toxicity of the particles to intestinal epithelial cells was investigated. A significant decrease in viability and a significant increase in ROS production were observed in some particles. With the outputs from all analyzes, an important step has been taken in the literature about the interaction and consequences of polystyrene nanoparticles with food, which is still not fully elucidated. With the studies carried out within the scope of the thesis, important findings were obtained about the diameter-dependent corona structure of the particles, their behavior in solution and their interaction with the food matrix, the changes they undergo in the body after digestion and during digestion, and their effects on enzymes. With the outputs obtained from this, it is aimed to fill an important gap in the literature and to create a resource for new researches. In the next stages, important contributions can be made by working with different food matrices or nanoplastics with different properties.