Divergent Supramolecular Gelation of Backbone Modified Short Hybrid delta-Peptides

Abstract

The ordered supramolecular assemblies of short peptides have been recently gaining momentum due to their widespread applications in biology and materials sciences. In contrast to the α-peptides, limited success has been achieved from the backbone modified peptides. The proteolytic stability and conformational flexibility of the backbone modified peptides composed of β-, γ-, and δ-amino acids can be explored to design ordered supramolecular gels and self-assembled materials. In this article, we are reporting the divergent supramolecular gels from a new class of short hybrid dipeptides composed of conformationally flexible new β(O)-δ5-amino acids. The hybrid dipeptide composed of β3- and β(O)-δ5-Phe showed the formation of transparent gels from the aromatic solvents, while the dipeptide composed of β(O)-δ5-Phe showed the thixotropic gel in phosphate buffered saline (PBS). In contrast, no organic or hydrogels were observed from the dipeptides composed of alternating α- and β(O)-δ5-Phe as well as γ4 and β(O)-δ5-Phe. The organogelation property displayed by the β3,β(O)-δ5-Phe dipeptide was further explored to recover the oil spills from the oil–water mixture. The thixotropic hydrogels displayed by the β(O)-δ5, β(O)-δ5-Phe dipeptide was further utilized as matrix along with cell culture medium to grow the cells in 2D-cell culture. Replacing the backbone −CH2– with “O” in the δ-Phe leads to the drastic change in the supramolecular behavior of δ-peptides. Overall, the short dipeptides from different backbone modified amino acids showed the divergent gelation properties and these properties can be further explored to design new functional biomaterials.