Interaction of non-aqueous dispersions of silver nanoparticles with cellular membrane models

In this work, silver nanoparticles (AgNPs) dispersed in non-aqueous media and stabilized with polyether block polymers amide (PEBA) were incorporated in Langmuir monolayers of dipalmitoylphosphatidylcho line (DPPC), which served as a cell membrane model. The AgNPs presented surface activity, disturbing the viscoelastic properties of the floating film. They expanded the monolayers decreasing their surface elasticity as observed with surface pressure-area isotherms. Polarization modulation reflection-absorption spectroscopy showed that the permanence of AgNPs at the air-water interface is favored by PEBA, affecting both the hydrophilic and the hydrophobic groups of the phospholipid. Brewster angle microscopy showed that the AgNPs lead to the formation of aggregates at the air-water interface, establishing domains that shear with each other due to the low lateral viscosity of irregular and nonmonomolecular domains. These data can be correlated to the possible toxicity and microbicide effect of AgNPs in lipidic surfaces such as in mammalian and microbial membranes. (C) 2017 Elsevier Inc.All rights reserved. (AU)