Multiscale Investigations of Nanomaterial-Surface Interactions to Predict Trophic Transfer and Transport
Tuesday, October 6, 2015
Nick Geitner, Ph.D.
CEINT Postdoctoral Associate
Abstract: The transport of engineered nanomaterials through complex environmental systems remains a critical question as nanotechnology continues to develop. Presented here is a synergistic mathematical, computational, and experimental approach to understanding trophic transfer and transport of nanoparticles in the environment. The mathematical model of trophic transfer was derived from a system of differential equations capturing the feeding rates of each organism as well as the rate of surface adhesion of the nanomaterial. This rate of adhesion is based on alpha, the probability of a particle adhering to a given surface upon a collision event. Values for alpha of gold nanoparticles of varying surface coatings upon algal cells were measured in the lab, and these values fed into the model. Model results can then be compared to experimentally observed trophic transfer into Daphnia magna. It was found that all relevant alpha values for surfaces in the system must be considered, and that even relatively small changes in the alpha value for algae is expected to lead to significant changes trophic transfer. The early stages of MD simulations of nanoparticles with environmental surfaces to understand alpha at the single-nanoparticle level will also be discussed. By coupling single-nanoparticle computational techniques, laboratory bench-scale experiments, and ecosystem level modeling, we hope to gain a far richer understanding of the drivers of nanoparticle transport in the environment.