Tuning the Morphology of Nanostructured Peptide Films by Introduction of a Secondary Structure Conformational Constraint: A Case-Study of Hierarchical Self-Assembly

Peptide self-assembly is ubiquitous in nature. It governs the organization of proteins, controlling their folding kinetics and preserving their structure stability and bioactivity. In this connection, model oligopeptides may give important insights on the molecular mechanisms and elementary forces driving the formation of supramolecular structures. In this contribution we show that a single residue substitution, i.e. Aib (?-aminoisobutyric acid) in place of Ala at position 4 of an -(L-Ala)5- homo-oligomer, strongly alters the aggregation process. In particular, this process is initiated by the formation of small peptide clusters that promote aggregation at the nanometer scale and, through a hierarchical self-assembly, lead to mesoscopic structures of micrometric dimensions. Furthermore, we show that the use of the well-established Langmuir-Blodgett technique represent an effective strategy for coating extended areas of inorganic substrates by densely-packed peptide layers, thus paving the way for application of peptide films as templates for biomineralization, biocompatible coating of surfaces, and scaffolds for tissue engineering.