The ever-growing applications in industrial and biomedical settings have created an increased demand for stable and biocompatible silver nanoparticles (AgNPs) with minimal adverse effects on the environment and human health. With 500 tons of AgNPs being produced every year and a million-dollar market in the line, it is critical to further our understanding of how physiochemical properties like shape, size, and surface chemistry drive their cellular uptake and toxicity. While numerous in vitro and in vivo mechanistic studies of AgNPs have been performed, many of these studies find high toxicity due to silver ion release. In this presentation, a systematic study of a series of engineered AgNPs that are shielded from Ag dissolution was performed. The toxicity of the AgNPs was assessed in vivo using embryonic zebrafish (Danio rerio), an established model for nanotoxicology studies due to their very similar molecular signaling processes, cell structure, anatomy, and physiology as other higher-order vertebrates, including humans. While toxicity studies elucidate the behavior of AgNPs, a better understanding of nanoparticle uptake and behavior inside the cell is crucial. Well-studied biomimetic lipid monolayers were employed to assess the interactions of NPs with a lipid monolayer using sum frequency generation (SFG) vibrational spectroscopy. We used SFG to directly probe the order of the acyl chains of the lipid monolayer, allowing for direct observation of how AgNP size and shape change the packing and ordering of the lipids in a model cell membrane, providing a fundamental understanding of how NPs interact with cells to drive uptake and toxicity. By combining in vivo toxicity studies with SFG spectroscopy and model membranes, we can further our understanding of how NP shape and size influence biological interactions without the confounding effect of ionic Ag. By understanding these interactions and their toxicity, we can get closer to finding silver nanoparticles for use in various medicinal applications without causing toxicity.

Stacey Harper

Appearances