Along with other aggregates, a hollow, spherical structure self-assembles from approximately 1,165 Mo wheels. This was termed a vesicle by analogy with lipid vesicles. Unlike lipid vesicles that are stabilised by hydrophobic interactions it is believed that the vesicle is stabilised by an interplay of van der Waals attraction, long-range electrostatic repulsion with further stabilization arising from hydrogen bonding involving water molecules encapsulated between the wheel-shaped clusters and in the vesicles' interior. The radius of the vesicle is 45 nm.