Controlled and Tunable Loading and Release of Vesicles by Using Gigahertz Acoustics.

Controllable exchange of molecules between the interior and the external environment of vesicles is critical in drug delivery and micro/nano-reactors. While many approaches exist to trigger release from vesicles, controlled loading remains a challenge. Herein, we show that gigahertz acoustic streaming generated by a nanoelectromechanical resonator can control the loading and release of cargo into and from vesicles. Polymer-shelled vesicles showed loading and release of molecules both in solution and on a solid substrate. We observed deformation of individual giant unilamellar vesicles and propose that the shear stress generated by gigahertz acoustic streaming induces the formation of transient nanopores, with diameters on the order of 100 nm, in the vesicle membranes. This provides a non-invasive method to control material exchange across membranes of different types of vesicles, which could allow site-specific release of therapeutics and controlled loading into cells, as well as tunable microreactors.