Recent progress in nanotechnology has led to the development of engineered nanoparticles (NPs), small size materials that exhibit specific physico-chemical properties. Due to their high reactivity, NPs have been incorporated in a number of common products and have been increasingly used in many different industrial fields over the last ten years. However, this recent enthusiasm has simultaneously raised serious concerns relative to the potential release of engineered NPs into natural environments, and to their potential negative effects on humans and ecosystems. It has been suggested that NPs can constitute a new class of micro-pollutants, and consequently their “life cycle” in natural environments including aquatic systems and soils needs to be understood to evaluate their potential impacts on living organisms.
Among the NPs, quantum dots (QDs) are widely used in electronic devices and biomedicine for in vivo imaging. Many studies have recently focused on direct exposure of model organisms (bacteria, algae) to QDs but only few of them were devoted to their transfer to aquatic systems, and no clear information is available regarding their fate in soils. In natural settings, QDs residence time may range from months to years, but critical information regarding the physico-chemical processes controlling QDs distribution, transformation and toxicity is still missing, highlighting the importance of molecular-scale characterization of QDs to accurately predict their fate in natural environments. The overarching goal of this project is to decipher how molecular-scale physico-chemical processes promoted by mineral surfaces and organic ligands, affect the transport, reactivity and dissolution of CdSe QDs soils. (Collaboration with A. Gélabert and M. Benedetti, Paris University)