Stimuli-responsive gelation of Fmoc-l-tyrosine derivatives to form supramolecular architectures via cold atmospheric plasma treatment

Abstract

The rapid self-assembly of peptides and amino acids into three-dimensional fibrous networks has been extensively investigated as a strategy for constructing supramolecular architectures. In this study, we demonstrate a unique strategy using cold atmospheric plasma (CAP) to assess the assembly behaviour of protected aromatic amino acid derivatives, such as Fmoc-L-tyrosine-OH and Fmoc-L-tyrosine(tBu)-OH. CAP generates reactive species that induce hydrolysis and oxidation of amino acids, leading to the formation of the self-assembled fibrous micro-structured gels of Fmoc-tyrosine-OH and Fmoc-tyrosine(tBu)-OH, underscoring the role of CAP-induced chemical transformations in modulating the hydrophobic–lipophilic balance of the assemblies. IR, CD and zeta potential analyses confirmed that the formation of these microstructures was primarily driven by aromatic interactions, π–π stacking, and other non-covalent interactions. Additionally, LC-MS analysis was employed to elucidate the molecular structural changes of the samples following CAP treatment, revealing the underlying mechanism of RONS-driven modifications. A remarkably low critical aggregation concentration (CAC) further demonstrates CAP's efficiency and reliability as a trigger for facilitating supramolecular assembly. The findings underscore CAP's versatility as a green, cost-effective, and tunable approach for the design of soft materials and the fabrication of peptide-based nanostructures, with significant potential in applications such as drug delivery, tissue engineering, and bioactive materials for diagnostics and therapeutic interventions.