The Dynamics and Toxicity of Quantum Dots in the Caenorhabditis Elegans Embryo

Abstract

<p> Quantum dots are semiconductor nanocrystals with unique optical properties that give them the potential to be excellent probes for bio-imaging applications. However, before quantum dots can be employed for such applications, their toxicity and cellular interactions need to be thoroughly assessed. The Caenorhabditis elegans (C. elegans) embryo was chosen as a test environment to study both the toxicity and dynamics of carboxyl terminated CdSe/ZnS quantum dots. Using confocal imaging, it was found that the C. elegans embryo is not morphologically affected by the introduction of quantum dots up to a concentration of about 1 OOnM. However, the embryo was observed to respond to the nanomaterial by packaging it into aggregates during development in a dose and time dependant manner. Image analysis and fluorescence correlation spectroscopy revealed that this packaging process happens from the nm scale to the J.Ull scale and that it reduces quantum dot mobility over development. This work shows that the dynamics of the quantum dots are highly influenced by the cellular environment in the embryo, as they appear to aggregate and possibly also interact with cellular structures and organelles in the embryo. </p>