Biomacromolecules, Vol.20, No.3, 1254-1262, 2019
Divergent Supramolecular Gelation of Backbone Modified Short Hybrid delta-Peptides
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 alpha-peptides, limited success has been achieved from the backbone modified peptides. The proteolytic stability and conformational flexibility of the backbone modified peptides composed of beta-, gamma-, and delta-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 beta(O)-delta(5)-amino acids. The hybrid dipeptide composed of beta(3)- and beta(O)-delta(5)-Phe showed the formation of transparent gels from the aromatic solvents, while the dipeptide composed of beta(O)-delta(5)-Phe showed the thixotropic gel in phosphate buffered saline (PBS). In contrast, no organic or hydrogels were observed from the dipeptides composed of alternating alpha- and beta(O)-delta(5)-Phe as well as gamma(4) and beta(O)-delta(5)-Phe. The organogelation property displayed by the beta(3),beta(O)-delta(5)-Phe dipeptide was further explored to recover the oil spills from the oil water mixture. The thixotropic hydrogels displayed by the beta(O)-delta(5), beta(O)-delta(5)-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 delta-Phe leads to the drastic change in the supramolecular behavior of delta-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.