Title
Self-Assembly of Unprotected Dipeptides into Hydrogels: Water-Channels Make the Difference
Author
Ottavia Bellotto, Slavko Kralj, Michele Melchionna, Paolo Pengo, Matic Kisovec, Marjetka Podobnik, Rita De Zorzi, Silvia Marchesan
Year
2021
Journal
ChemBioChem
Abstract
Unprotected dipeptides are attractive building blocks for environmentally friendly hydrogel biomaterials by virtue of their low-cost and ease of preparation. This work investigates the self-assembling behaviour of the distinct stereoisomers of Ile-Phe and Phe-Ile in phosphate buffered saline (PBS) to form hydrogels, using transmission electron microscopy (TEM), attenuated total reflectance infrared spectroscopy (ATR-IR), circular dichroism (CD), and oscillatory rheometry. Each peptide purity and identity was also confirmed by 1H- and 13C-NMR spectroscopy and HPLC-MS. Finally, single-crystal XRD data allowed the key interactions responsible for the supramolecular packing into amphipathic layers or water-channels to be revealed. The presence of the latter in the crystal structure is a distinctive feature of the only gelator of this work that self-organizes into stable hydrogels, with fast kinetics and the highest elastic modulus amongst its structural isomers and stereoisomers.
Instrument
J-815
Keywords
dipeptides, environmental, FTIR, CD, structural isomers, stereoisomers