Self-limited self-assembly of monodisperse colloidal vesicles

Understanding vesicle formation is essential for biological processes, yet direct visualization remains challenging due to the nanoscale dimensions and rapid dynamics of lipid bilayers. Here, we study vesicle formation pathways using colloidal membranes assembled from monodisperse filamentous phagemid and non-adsorbing polymer. One rod-length thick fluid membranes assemble from an isotropic solution and gradually increases in size. Once a membrane reaches a critical size it undergoes mechanical instability due to increased edge energy. Consequently, it rapidly transforms into edgeless closed vesicles that are monodisperse in size. Our experimental system allows for quantitative visualization of pathways of vesicle formation in real-time with near molecular detail. It provides insight into biological phenomena such as exocytosis as well as a powerful experimental platform for creating monodisperse permeable capsules.