Effects of silver nanoparticles on the morphology and membrane permeability of giant unilamellar vesicles and their mechanistic insights.

Silver nanoparticles (AgNPs) are extensively used in healthcare, medicine, and environmental fields owing to their strong antiviral and antibacterial properties. Although these NPs interact with cellular biomembranes or vesicular lipid membranes, their mechanisms of interaction under physiological conditions using cell-mimetic giant unilamellar vesicles (GUVs) have been rarely investigated. In this study, we focused on the interaction of AgNPs with cell-sized GUVs and investigated deformation, membrane permeation, and change in membrane area under 0.3 - 5.0 μg/mL concentrations of AgNPs. The synthesized particles exhibited an average size of 58.1nm and a zeta potential of -6.9mV. The deformation of GUV and the fraction of deformation increase with the increase of AgNPs concentration. The encapsulating calcein of GUVs leaked out through the membranes while interacting the AgNPs, indicated the nano-sized pore formation in the membranes of vesicles. The leakage constant increased with the increase of NPs concentration, as well as the pore size. The membrane area of a GUV measured by micropipette technique exhibits a dynamic response: an initial rapid expansion, followed by a gradual contraction, and a subsequent slight increase over time. This provides insights into AgNPs-GUVs binding dynamics. These investigations help to understand the mechanism of interaction of AgNPs in the cell membranes which might be used in several biophysical and biomedical applications.