Laboratoire Matière et Systèmes Complexes

Long term fate of iron oxide nanoparticles in the organism

Jeanne Volatron, Laboratoire MSC

The use of iron oxide nanoparticles in the field of nanomedecine is rapidly expanding, allowing new treatments for various diseases. Thanks to their size, magnetic properties and functionalization, metal oxide nanoparticles are widely used for their significant potential in diagnostic as well as remotely-activated therapy. Although the potential toxicity of such nanomaterials is extensively studied, their long term fate, biotransformation and degradation in the organism are still poorly understood. Here we propose a multi-scale approach to study the life cycle of metal oxide nanoparticles in biological environments based on the evolution of their physical and morphological properties. We first characterize the biotransformation of iron oxide nanoparticles in vivo in mice. The main challenge is to differentiate iron stemming from the nanoparticles from the endogeneous iron in the body. This specific tracking problem is routinely encountered in geochemical studies and solved by labelling the target material with minor stable isotopes. Therefore, iron oxide nanoparticles enriched in the minor stable isotope 57Fe were synthetised and injected intravenously in mice. Preliminary results regarding the processing of iron oxide nanoparticles in vivo will be presented. It was demonstrated earlier that iron oxide nanoparticles undergo local intracellular degradation within lysosomes of macrophage in spleen and liver1. The coexistence of iron rich ferritin protein in the vicinity of degraded nanoparticles suggests the implication of these iron storage protein in the remediation of iron released by nanoparticles. We will present results on the role of ferritin in the degradation of iron oxide2 and cobalt iron oxide3 and the mechanism of biological recycling, remediation and detoxification of nanoparticles mediated by endogenous proteins.

Synthetic Embryology

Jean-Louis Plouhinec, Laboratoire MSC

Embryos display amazing morphogenetic abilities. These abilities are nevertheless difficult to study in situ in embryos, owing to their complex geometry and the multiple processes occurring simultaneously. We have developped in the lab a simple micropatterning system to control the geometry of mouse embryonic stem cells colonies. I will show how this can be used to control differentiation patterns in these colonies.