This communication describes the co-assembly of polydopamine spheres, either bare or coated with Fe3O4 magnetic nanoparticles, with the short aromatic peptide diphenylalanine. The combination of polydopamine particles and diphenylalanine generated tubular structures decorated with adhesive spherical particles, while the co-assembly of the polydopamine spheres coated with magnetic Fe3O4 nanoparticles with diphenylalanine resulted in the formation of a magnetic hydrogel. These new architectures may be useful as new vehicles for several applications including tissue regeneration and drug delivery.