Etudes des interactions physicochimiques et biologiques entre des nanoparticules manufacturées et des bactéries de l'environnement.

Ophélie Zeyons 1
1 LIONS - Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire
NIMBE UMR 3685 - Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M)
Abstract : Thanks to their particular properties due to their size, the nanomaterials (dimension < 100 nm) are widely used in many industrial applications (daily care products, nanostructured materials...). However, their growing use frightens because of their uncertain impact on humans and environment. This study is dedicated to a deep understanding of the physicochemical and biological interactions between two cellular models from the environment: Synechocystis (cyanobacteria essential for the biosphere) and Escherichia coli (bacteria of mammalian intestines) with cerium oxide nanoparticles (ex: diesel additive).
The complexity of the study of nanoparticles requires a different approach (multidisciplinary) from those of toxicity tests of classic compounds. Indeed, we showed that the physicochemical parameters (stability, aggregation, dissolution and surface chemistry) of nanoparticles in the contact medium, strongly influence the toxicity. Furthermore, the physicochemical interactions (flocculation, adsorption, redox mechanisms) are linked to the biological model and especially the presence of exopolysaccharides (for Synechocystis) as natural barrier between the cell wall and the nanoparticles. Moreover, the composition of the nanoparticles dispersion medium (particularly the pH) has a major influence on the toxicity (survival and membrane integrity), whereas for E. coli, the nanoparticles are the main culprits for the mortality (confirmed by metabonomic studies via NMR).
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Ophélie Zeyons. Etudes des interactions physicochimiques et biologiques entre des nanoparticules manufacturées et des bactéries de l'environnement.. Physique [physics]. Université Pierre et Marie Curie - Paris VI, 2008. Français. ⟨tel-00331931⟩

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