Warsaw University of Life Sciences, Poland
Paula Kielbik is currently PhD student at the Warsaw University of Life Sciences at Faculty of Veterinary Medicine. She completed both her Bachelor and Master of Science degrees under supervision of dr Michal Godlewski in Nanotechnology Laboratory in collaboration wit 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 Paula 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.
Zinc oxide nanaoparticles (ZnO NPs) became promising material for numerous applications, includind 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 fluorescent1 ZnO NPs doped with Europim (ZnO:Eu) to mice (n=35). After 3h, 24h, 7d, 14d or 1m 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 elimination2. An interesting pattern of biodistribution of NPs in the brain was also observed. Following 3h 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 NPs3 and Y2O3:Eu NPs4. The peek of NPs transfer to the brain seems to take place 24h 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 consequential of biodegradation of NPs and their efficient elimination via neuronal transport5.