l-Dopa in small peptides: an amazing functionality to form supramolecular materials
L-Dopa (3,4-dihydroxyphenylalanine) is a chiral amino acid generated via biosynthesis from L-tyrosine in plants and some animals. The presence of multiple interacting sites makes L-Dopa a multifunctional building block for the preparation of supramolecular materials. The possibility to form hydrogen bonds and the presence of the aromatic ring allow L-Dopa molecules to interact through a series of non-covalent interactions. The additional presence of the catechol moiety really makes this compound unique: not only does it have implications in the self-assembly process of Dopa itself and with other substrates, but also it highly increases the number of applications of the final material, since it works as an antioxidant, radical trapper, metal chelator, reducing agent and adhesive. L-Dopa and catechol containing derivatives have been extensively introduced inside both synthetic and natural polymers to obtain amazing functional materials. In this review we report the preparation of small peptides containing L-Dopa, focusing on the supramolecular materials that can be obtained with them, ranging from fibrils to fibres, gels, films and coatings, all having the different applications mentioned above and many others.