Determining the nanoparticle-algae interaction in the bioaccumulation process

The use of engineered nanomaterials (NMs) raises concern regarding their fate in environmental compartments and their potential effects on aquatic organisms. One of the singularities of these substances is their duality of action, both physical and chemical. In the chain of events leading to the occurrence of a deleterious effect, the interaction between a NM and a biological organism is one essential event. Therefore, understanding the links between the properties of NMs and the physical interaction phenomenon (adhesion, internalization) with aquatic organisms, is essential in a context of a priori hazard assessment and for the categorization of these substances within a regulatory purpose. This work aims at determining the interaction of various NMs with freshwater microalgae, to gain a better understanding of its implication in bioaccumulation and biological effect. Green algae with different cell wall composition were separately exposed to different NMs suspensions. Flow cytometry and microscopic observation showed evidence of NMs-algae interaction. A dose-dependent response is observed for every type of NMs and a cell wall specificity is showed. So far, two parameters were identified as having a major role in the NMalgae interaction: i) the cell wall composition, as each algae had a different response to the set of tested NMs; and ii) the NMs physicchemical properties; because for a given algae cell wall type, a different degree of increased algal complexity was observed according to each NM