Concentration-dependent fabrication of short-peptide-based different self-assembled nanostructures with various morphologies and intracellular delivery property

Abstract

The fabrication of supramolecular architectures with various morphologies via the self-assembly of appropriate molecular building blocks is a proficient and convenient fabrication approach. Moreover, controlling the key parameters responsible for the self-assembly process is vital for understanding the fundamental aspects of molecular self-assembly, which provide insights into the fabrication of new assemblies with functional nano-architectures. To this end, in the present study, we report the synthesis of a simple tripeptide Boc-Phe-Phe-Glu-(OH)₂ (PS1) and the mechanism for the concentration-dependent self-assembly of this tripeptide building block. This peptide self-assembled into discrete spherical assemblies at a low concentration. An increase in concentration of the monomeric building block during self-assembly generated nanotubes by connecting the nanospheres through neck formation. At higher concentration and with a prolonged incubation time, the self-assembly fabricated necklace-like supramolecular architectures comprise both linear and spherical units together. Furthermore, the spherical assemblies produced with a lower concentration of monomeric building blocks were encapsulate small molecules as well as able to release these inside the cells. Therefore, these spherical assemblies represent a potential candidate for the delivery of exogenous entities directly into cells and may behave like conventional sphere-based drug-delivery vehicles. To the best of our knowledge, this is the first report on the fabrication of a biomolecular necklace-like complex assembly with a bi-component type of morphology from a single short peptide-based molecular backbone.