Formation of Nanostructures by Peptides

Background: Amyloid fibrils, which are implicated in several diseases, are highly ordered structures formed by aggregation of proteins. Intriguingly, several short peptides, some of which are unrelated to the disease-causing proteins, also aggregate to form amyloid fibrils in vitro. The aggregation behavior of these short peptides can be modulated so that they form nanostructures that are not in any way related to amyloid fibrils. These observations have led to extensive research aimed at getting insights into how peptides aggregate to form amyloids as well as non-amyloidogenic structures. Methods: This review examines the aggregation behavior of peptides that form highly polymorphic structures including fibrils, nanotubes, nanospheres and hydrogels. The review also describes how short peptides composed of only two and three hydrophobic and aromatic amino acids can selfassemble to form nanotubes and nanospheres. Results: Peptides with widely varying amino acid composition and lengths aggregate to form indistinguishable fibrils and nanostructures. The potential application of these aggregated structures in the design of novel biomaterials is reviewed and highlighted. Conclusion: It is evident that highly polymorphic aggregated structures of peptides can be obtained by varying conditions such as solvent of dissolution, temperatures, pH and even surfaces of deposition.