Deformation and motion of giant unilamellar vesicles loaded with gold nanoparticles driven by induced charge electro-osmotic flow

Abstract

A vesicle is a spherical structure composed of a phospholipid bilayer that is used as a container for chemicals, both it in vivo and it in vitro systems. In both cases, the vesicles can be passively moved using external molecular motors or flows. The active motion of the vesicles can potentially expand their applications in microfluid devices. In this study, we created giant unilamellar vesicles (GUVs) that loads dodecanethiol-functionalized gold nanoparticles (AuNPs) using natural swelling method. An external alternating current (AC) electric field was applied to the sample to drive the system. A flow was confirmed with dense optical flow method around GUVs, even in the absence of AuNPs. The quadratic dependence of the flow on applied elecric fields confirms that the flow is due to induced charge electro-osmotic (ICEO) mechanism. Furthermore, the GUVs containing AuNPs moved and deformed significantly under external AC electric fields compared with those without AuNPs. We also confirmed that the translational speed of GUVs was positively correlated with the volume ratio of AuNPs. These experimental results suggest that the motion and deformation of GUVs were cause by ICEO flow, which was unbalanced owing to the presence of localized AuNPs on the membrane.