ABSTRACT
Peptides of natural and synthetic origin are compounds involved in a wide variety of biological roles. They act as hormones, enzyme substrates and inhibitors, antibiotics, biological regulators, and so on. Therefore, peptides play an essential role in biotechnological applications as therapeutic and diagnostic agents. Their advantages depend on the strategy applied to produce them and include biocompatibility, low cost, tunable bioactivity, chemical variety, and specific targeting. Moreover, they are easily synthesized, for example, by using solid-phase peptide methodologies where the amino acid sequence can be exactly selected at the molecular level by tuning the basic units. The regular a-helical peptides with helices are shown to aggregate around each other and their structure evolves in nanofibers. These a-helical peptides can also self-assemble into nanofibers if they have at least 30 amino acid residues, through helical coiled-coil structures. The non-covalent interactions should be taken into high consideration for these grounds, especially when designing peptide self-assembled nanostructures for drug delivery.
