Tetrapeptidic Molecular Hydrogels: Self-assembly and Co-aggregation with Amyloid Fragment Aβ1-40

A new family of isomeric tetrapeptides containing aromatic and polar amino acid residues that are able to form molecular hydrogels following a smooth change in pH is described. The hydrogels have been studied by spectroscopic and microscopic techniques showing that the peptide primary sequence has an enormous influence on the self-assembly process. In particular, the formation of extended hydrophobic regions and the appearance of -stacking interactions have been revealed as the driving forces for aggregation. Moreover, the interaction of these compounds with amyloid peptidic fragment A1-40 has been studied and some of them have been shown to act as templates for the aggregation of this peptide into non--sheet fibrillar structures. These compounds could potentially be used for the capture of toxic, soluble amyloid oligomers.