Self-assembly of supramolecular nanostructures from phenylalanine derived bolaamphiphiles

Abstract

The growth and self-assembly of phenylalanine derived bolaamphiphiles was investigated. The self-assembly process was studied at hydrophobic–hydrophilic interfaces and under aqueous conditions at different pH. The formation of various structures in microscale and nanoscale was examined using atomic force microscopy, transmission electron microscopy, dynamic light scattering, ultraviolet-visible spectroscopy and infrared spectroscopy. It was observed that the types of structures formed were dependent on both the growth conditions and the chain lengths of the hydrocarbons linking the head groups. At lower pH, tubular formations were observed in high yield for all bolaamphiphiles synthesized compared to higher pH. As the size of the hydrophobic chain length connecting the amino acid head groups increased, the nanotubes were formed in higher yield and were observed to be more elongated and well-defined. In some cases, nanofibers, spheres and rod-like structures were also obtained at aqueous/organic interfaces and in different pH. The investigation of the self-assembly process of such peptide bolaamphiphiles can give further insight into the dynamics of formation of various supramolecular structures. The materials formed were found to be highly stable and can be potentially used as scaffolds for biomaterials and fabrication of nanodevices.