Silver nanoparticles have been shown to have strong antimicrobial effects against many organisms, including those resistant to conventional antibiotics. However, the exact mechanism of action remains controversial. In particular, the factors controlling specificity of these interactions are not known. In this experiment, we will examine the interaction between anionic or cationically coated NP's with both eukaryotic and prokaryotic membrane mimics, in order to better understand the factors affecting the initial membrane interaction with both membrane types.