Resumen

Toxicity of cerium oxide nanoparticles was tested in different biological models such as prokaryotic (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis spores), eukaryotic yeast, germination radicle and development of Lactuca sativa seed as well as damage to human leukocyte DNA.

The nanoparticles were sonicated at different pH values and time, and then mixed with three different surfactants (i.e. PVP Polyvinylpyrrolidone, Triton X114 and Tween 80) at 0.002% v/v. It was found that sonication enhanced colloidal dispersion and produced an average particle size of 400 nm. The material was toxic to E. coli at pH 7 when sonicated and M9 minimal media was used. The toxic effect on minimal media increased when non-ionic surfactants were added. The use of CeO2 plus surfactant improved the minimal inhibitory concentration (MIC) against E. coli using Tween 80. The most striking effect occurred with this surfactant resulting in a MIC value of 0.150 mg mL-1 compared to 3 mg mL-1 of cerium oxide alone. Regarding the germination model, it was found that the toxic concentration was 0.5 mg mL-1. At this concentration germination was observed, but not radicle growth. It was found that leukocyte DNA was affected in a concentration of 1 mg mL-1for the tested nanoparticles in all tested conditions.

These findings suggest the importance of the different factors interacting with the nanoparticles, such as surfactants, particle size, synthesis method, the physical chemistry of nanomaterials and the type of test organisms can affect in different ways the distinct prokaryotic and eukaryotic and lead to an unexpected toxic effect in materials considered as innocuous. In consequence, in the future this could affect the environment and microscopic and macroscopic organisms.

Palabras clave: Toxicidad, Nanotecnología, CeO2.

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Cuahtecontzi Delint, R. 2013. Estudio de Toxicidad de Nanopartículas de CeO2 en Diferentes Sistemas Biológicos. Tesis Licenciatura. Nanotecnología e Ingeniería Molecular. Departamento de Ciencias Químico Biológicas, Escuela de Ciencias, Universidad de las Américas Puebla. Mayo. Derechos Reservados © 2013.