An aggregate of smaller particles packaged into a larger membrane-bound structure. The aggregates are formed by attachment of biotin to individual liposomes or other small particles, then cross-linked with streptavidin. The larger aggregates thus formed are partially broken into appropriate sizes by extrusion. In parallel, biotin-labeled films of phosphatidylserine or phosphatidylethanolamine in the presence of Ca²⁺ spontaneously roll up into jelly roll-like cochleate cylinders. The biotin labels of the cylinders are saturated with streptavidin and mixed with the aggregates, which adhere to the cylinders through their remaining open biotin residues. As the cylinders are uncoiled by addition of a Ca²⁺ chelator, they wrap around the adhering aggregates to form vesosomes.