Short Peptides as Tunable, Switchable, and Strong Gelators

This Perspective outlines our current understanding of molecular gels composed of short and ultrashort peptides over the past 20 years. We discuss in detail the state of the art regarding self-assembly mechanisms, structure, thermal stability, and kinetics of fibril and/or network formation. Emphasis is put on the importance of the combined use of spectroscopy and rheology for characterizing and validating self-assembly models. While a range of peptide chemistries are reviewed, we focus our discussion on a unique new class of ultrashort peptide gelators, denoted GxG peptides (x: guest residue), which are capable of forming self-assembled fibril networks. The storage moduli of GxG gels are tunable up to 100 kPa depending on concentration, pH, and/or cosolvent. The sheet structures of the fibrils differ from canonical beta-sheets. When appropriate, each section highlights opportunities for additional research and technologies that would further our understanding.

Automated summary

This Perspective provides an overview of molecular gels composed of short and ultrashort peptides over the past two decades, focusing on self-assembly mechanisms, structure, thermal stability, and kinetics of fibril and/or network formation, with an emphasis on the importance of spectroscopy and rheology in characterizing self-assembly models. It discusses a unique class of ultrashort peptide gelators, GxG peptides, capable of forming self-assembled fibril networks with tunable storage moduli up to 100 kPa, and highlights opportunities for further research and technologies to advance understanding in this area.