In recent years, considerable effort has been devoted to the design and controlled fabrication of structured materials with functional properties. The layer by layer buildup of polyelectrolyte multilayer films (PEM films) from oppositely charged polyelectrolytes offers new opportunities for the preparation of functionalized biomaterial coatings. This technique allows the preparation of supramolecular nano-architectures exhibiting specific properties in terms of control of cell activation and may also play a role in the development of local drug delivery systems. Peptides, proteins, chemically bound to polyelectrolytes, adsorbed or embedded in PEM films, have been shown to retain their biological activities.