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Biology session

Investigation of particle size dependent changes in kinetics of metals in animal model
Szekeres Barbara Gabriella III. évfolyam
University of Veterinary Medicine Budapest, Department of Pharmacology and Toxicology
Supervisor: Dr. Csaba Kővágó


In order to protect the industrial workers' health, we should know and control properly the effects and risks of any type of malicious emissions. During a welding process a considerable amount of emitted particles are bigger than 100 nanometer in diameter, however we know about some technologies, which can emit ultrafine particles that range from 1 to 100 nm in scale. Previous researches pointed out the fact that some chemical substances act differently in biological systems depending on their particle size. With our research, we could make relevant statements about the kinetics of nanoparticles, used not only in welding process, but also in other areas, like the food industry.

We used BALB-C albino mice in our experiment. Smoke, generated by Tungsten Inert Gas (TIG) welding and Manual Metal Arc (MMA) welding processes, was being made to breathe in with mice for four hours. We have taken samples from lungs, spleens, livers and kidneys following 24 and 96 hours after the treatment. We did both microscopic and chemical examinations, searching for structural deviations and damages. As for histopathological examinations hematoxilin-eosin staining and Perls' Prussian blue reaction has been performed. We measured the organs' and the welding materials' metal concentrations.

Results showed that iron substance was increasing in spleen after 24 hour passed, but liver's iron level did not change compared to the control group. Since the iron substance concentration decreased to normal level in the spleen 96 hours after the treatment, we suppose that the absorbed metal was eliminated via the urine or via enteric way. Iron particles could have been transported from lungs to spleen in case of all used welding technologies, so both the bigger and nano- sized iron particle acted the same way in the biological system. We found that the manganese distribution showed size-dependency. The smoke emitted by the MMA technology contained bigger manganese particles, which aggregated in the lungs and the spleen, whereas the concentration of manganese of the liver was normal. The smoke of the TIG technology contained ultrafine sized metal particles, thus the inhaled manganese nanoparticles reached the liver after 96 hours and the concentration of which was rising.

In conclusion our research succeeded to show the size-dependent kinetics of a metal in a biological system. Our results are congruous with previous experiments, that declared the difference in biological effect and transport properties of a particle according to its size. These experiments showed that the properties of a nano size particle is mostly depending on the size and not on the particles’ chemical composition. The results proved that we need to do further research on the biological effects of nanoparticles, since these can differ quite significantly from the chemically same but larger sized particles.

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