Newly prepared water-soluble amphipatic hyperbranched organic polymers are used as nanocontainer and as carriers for large metal-organic molecules such as metallo-porphyrins. The hydrosoluble dendrigrafts are constituted by a polystyrene hydrophobic core surrounded by a polyvinyl ether hydrophilic shell. These nanometer-sized amphipatic macromolecules with an average diameter of about 100 nm and narrow polydispersity are fully soluble in aqueous media. Their capacity to encapsulate and transport metallo-porphyrins in aqueous media is investigated. Complexation studies show that up to several thousands of guest molecules can be embedded into each amphipatic dendrigraft macromolecule. (C) 2004 Elsevier Ltd. All rights reserved.