Dipeptide derived from benzylcystine forms unbranched nanotubes in aqueous solution

The essence of modern nanotechnology is manifested in the formation of well-ordered nanostructures by a process of self-association. Peptides are among the most useful building blocks for organic bionanostructures such as nanotubes, nanospheres, nanotapes, nanofibrils, and other different ordered structures at the nanoscale. Peptides are biocompatible, chemically diverse, and much more stable and can be readily synthesized on a large scale. Also, they have diverse application in biosensors, tissue engineering, drug delivery, etc. Here, we report a short cystine-based dipeptide, which spontaneously self-associates to form straight, unbranched nanotubes. Such self-assembled nanobiomaterials provide a novel possibility of designing new functional biomaterials with potential applications in nanobiotechnology. The formation of nanotubes in solution state has been demonstrated by atomic force microscopy and scanning electron microscopy. Infrared absorption and circular dichroism demonstrated the intermolecular β-sheet-like backbone hydrogen bonding in juxtaposing and stacking of aromatic side chains.