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Biography

Paula Kielbik is currently a PhD student at Warsaw University of Life Sciences, Faculty of Veterinary Medicine. She completed both her Bachelor Degree and Master of Science Degree under supervision of Dr Michal Godlewski in Nanotechnology laboratory in collaboration with Polish Intitute of Physics. In her scientific work, she focused mainly on “Biodistribution of biodegradable nanoparticles in the living organism”. The main aspect of her work was transfer of nanoparticles through the organism barriers (i.e. intestinal barrier, blood-brain barrier, blood-testis barrier) by ZnO-derieved NPs in adult organism. Working as a member of a team in Nanotechnology laboratory, she was involved in the development and assessment of compherehesive methodology for the evaluation of gastrointestinal absorption, circulation and elimination from the organism of biodegradable nanoparticles.

Abstract

Zinc oxide nanaoparticles (ZnO NPs) became promising material for numerous applications, including biomedicine. Avaible reports assessing their biodistribution present contradictory conclusions. Furthermore transfer of NPs through the blood-brain barrier has not been reported extensively. In our study, we orally administrated fluorescent. ZnO NPs doped with Europim (ZnO:Eu) to mice (n=35). After 3 h, 24 h, 7 d, 14 d or 1 m mice were sacrificed and internal organs were collected for the assessment of biodistribution and localization of NPs in the organism. For the analyses, we proposed a novel comprehensive and innovative approach. Along with the measurement of Zn concentration in organs with spectroscopy method (AAS), we performed quantitative and qualitative cytometric evaluation of collected samples. The distribution patterns of ZnO:Eu NPs within tissues were statistically assessed with scanning cytometry, while the extent of biodegradation was semiquantitatively elucidated by confocal microscopy. Results revealed very rapid and efficient uptake and distribution of ZnO:Eu NPs to key organs and tissues, also crossing physiological barriers. Spleen, as well as fat tissue were responsible for accumulation of NPs, and liver with kidney were designated for their elimination. An interesting pattern of biodistribution of NPs in the brain was also observed. Following 3 h after IG administration, we observed crossing of the blood-brain barrier by ZnO:Eu NPs and their uniform distribution in the brain. Similar observations were reported earlier for non-biodegradable ZrO2:Pr NPs and Y2O3:Eu NPs. The peek of NPs transfer to the brain seems to take place 24 h post IG with majority of NPs allocated in the areas of dense neuronal networks, limbic system and cerebellum. During following days, we observed a drop of NPs-related fluorescence. However, the association with limbic system and dense neuronal networks remained. We speculate that elimination of the NPs from the brain might be consequential of biodegradation of NPs and their efficient elimination via neuronal transport.