Method for the preparation of nano- and mesosized particles consisting of a lipid layer comprising at least one amphiphile and a core of an inorganic compound and/or a metal, comprising: (i) dissolving in a common solvent at least one self-aggregating amphiphile with at least one inorganic, organometallic or metallorganic precursor of said inorganic compound or metal; and (ii) either injecting the resulting solution into an aqueous solution or drying the resulting solution and re-hydrating it, so as to form particles in which the precursor is encapsulated by the amphiphile(s) and is converted therein to said inorganic compound and/or metallic solid form.