A submicron structure comprising a silica body defining a plurality of pores that are suitable to receive molecules therein, and having a surface, and a phospholipid bilayer coating the surface, wherein said submicron structure has a maximum dimension of less than one micron, and wherein the phospholipid bilayer stably seals the plurality of pores and wherein the submicron structure is a member of a monodisperse population of submicron structures.
